Pipe Location Research Articles

Suppression of the influence of surface waves on shear wave imaging for buried pipe location

Shear wave imaging has been proposed to detect shallow buried target objects in recent years. However, moderate results have been achieved with limited success since the resultant surface waves hinder the practical applicability of the method. In this paper the influence of surface waves is reduced prior to the image fusion for pipe localization. Field tests were carried out in the Hefei Institute of Public Safety, Tsinghua University. A sensor array was adopted to measure the ground surface vibration in response to the shear wave excitation. The method of connected subgraph traversal is applied to each image to show the suspected depth region of the target pipe. The fused image is subsequently obtained by extracting and fusing the suspected feature regions from the sequence imaging results and attenuating them with equal weighting. The image is finally analyzed to identify the burial depth. Furthermore, the effect of different sensor types and the interference effect of ambient noise on the imaging results are investigated experimentally. Test results show good agreement between the detected and actual depth of the buried pipeline.

A Simple Conservation Tool to Aid Restoration of Amphibians following High-Severity Wildfires: Use of PVC Pipes by Green Tree Frogs (Hyla cinerea) in Central Texas, USA

Amphibians are the most threatened vertebrate class based on the IUCN Red List. Their decline has been linked to anthropogenic activities, with wildfires being among the most conspicuous agents of habitat alterations affecting native amphibians. In 2011, the most destructive wildfire in Texas history occurred in the Lost Pines ecoregion of central Texas, USA, burning 39% of the 34,400 ha forest and drastically decreasing available habitats for many native wildlife species, including the green tree frog (Hyla cinerea). We investigated use of PVC pipes as artificial refuges for green tree frogs in different habitats within this post-fire pine forest. We monitored green tree frog use of small (diameter 38.1-mm, 1.5 inch) and large (diameter 50.8-mm, 2 inch) pipes located adjacent to, and 5 m from, ponds in burned and unburned areas over a 5-month period. We caught 227 frogs, 101 (24 adults and 77 juveniles) in burned and 126 (61 adults, 63 juveniles, and 2 unknown) in unburned areas. A relationship between pipe use by adults and/or juveniles and pipe location in burned versus unburned areas was found, but pipe use by adults and/or juveniles and pipe size were independent. Pipe use by adults and/or juveniles and pipe size were also independent. Juveniles were more frequently observed in pipes located adjacent to ponds. Our results confirmed that PVC pipes merit consideration as a simple, inexpensive, conservation tool to aid in restoration of green tree frog populations after high-severity wildfires. Such artificial refuges may be particularly important for survival of juveniles in severely altered post-fire habitats.

Multi-objective optimization and exergoeconomic evaluation of a hybrid geothermal-PVT system integrated with PCM

The main purpose of this research is to study the techno-economic analysis of a photovoltaic thermal collector (PVT) combined with phase change materials (PCM) and ground source heat pump (GSHP). In the first step of this study, a numerical transient simulation of a water-to-water GSHP was developed by using a vertical U-type ground source heat exchanger (GSHX) and variable speed drive (VSD) compressor in the multi-usage operation modes (heating and cooling). To achieve the most supreme system performance, the multi-objective optimization of the Levelized cost of energy (LCOE) and exergy efficiency was done by using the multi-objective non-dominated sorting genetic algorithm version || (NSGA-||). This algorithm considers substantial elements such as the number of boreholes, depth of drilling for the location of pipes in GSHX, setpoint temperature of fan coil, length of converters, the number of PVT panels, slope and direction of PVT panels, the number of batteries, volume of the storage tank of phase change materials and percentage of phase change materials in the tank. The simulation of the heat pump is accomplished through a numeral coding in the Engineering Equation Solver (EES) and also for the optimization part, a programming method used in the MATLAB program. Moreover, due to the evaluation of the transient response of the model, TRNSYS software was implemented. Based on the research achievements, the Single objective optimization of exergy efficiency for the combined PVT-PCM and GSHP systems can be conducted to the highest solar factor (SF) and the lowest amount of urban electricity consumption. Furthermore, the calculation of the annual required load of the building for different scenarios has shown that the use of collectors in this combined system has reduced the total load of the building by 6.5%. The maximum percentage of PVT energy efficiency belongs to the first scenario with a value of 53% and the lowest one with a difference of 43% is for the fourth scenario.

Discussion of “Effect of Pipe Size and Location on Water-Main Head Loss in Water Distribution Systems” by Saeed Hashemi, Yves Filion, Vanessa Speight, and Andrew Long

Discussion of “Effect of Pipe Size and Location on Water-Main Head Loss in Water Distribution Systems” by Saeed Hashemi, Yves Filion, Vanessa Speight, and Andrew Long

Discussion of “Effect of Pipe Size and Location on Water-Main Head Loss in Water Distribution Systems” by Saeed Hashemi, Yves Filion, Vanessa Speight, and Andrew Long

Discussion of “Effect of Pipe Size and Location on Water-Main Head Loss in Water Distribution Systems” by Saeed Hashemi, Yves Filion, Vanessa Speight, and Andrew Long

Magnetohydrodynamics thermogravitational convective in a novel I-shaped wavy-walled enclosure considering various inner hot pipe locations

Magnetohydrodynamics thermogravitational convective in a novel I-shaped wavy-walled enclosure considering various inner hot pipe locations

Underground Pipeline Identification into a Non-Destructive Case Study Based on Ground-Penetrating Radar Imaging

Ground-penetrating radar (GPR) has become one of the key technologies in subsurface sensing and, in general, in nondestructive testing (NDT), since it is able to detect both metallic and nonmetallic targets. GPR has proven its ability to work in electromagnetic frequency range for subsoil investigations, and it is a risk-reduction strategy for surveying underground various targets and their identification and detection. This paper presents the results of a case study which exceeds the laboratory level being realized in the field in a real case where the scanning conditions are much more difficult using GPR signals for detecting and assessing underground drainage metallic pipes which cross an area with large buildings parallel to the riverbed. The two urban drainage pipes are detected based on GPR imaging. This provides an approximation of their location and depth which are convenient to find from the reconstructed profiles of both simulated and practical GPR signals. The processing of data recorded with GPR tools requires appropriate software for this type of measurement to detect between different reflections at multiple interfaces located at different depths below the surface. In addition to the radargrams recorded and processed with the software corresponding to a GPR device, the paper contains significant results obtained using techniques and algorithms of the processing and post-processing of the signals (background removal and migration) that gave us the opportunity to estimate the location, depth, and profile of pipes, placed into a concrete duct bank, under a structure with different layers, including pavement, with good accuracy.

Research on Leak Location of Liquid-filled Pipe Based on Frequency Dispersion Characteristics

Due to the material problems and force majeure factors, the leakage will be occurred on the liquid-filled pipe resulting in waste of resources, environmental pollution and even endangering safety. Acoustic wave detection technology is widely used in buried pipeline leak detection, this technology mainly uses the wave (n=0, s=1) in the pipeline acoustic wave to locate the leak. When the leakage acoustic signal propagates along the liquid-filled pipe, the frequency dispersion characteristics can be obtained by wavelet decomposition. And there is a time delay (time difference) value between the leaky acoustic signals collected by the sensors at both ends of the leak. The outputs show that the results obtained by wavelet decomposition are in good agreement with the theoretical calculation results. Based on the obtained dispersion relation, the time delay values at different characteristic frequencies are analyzed by the cross-correlation method, and the leak location accuracy is discussed. This research content provides theoretical support and engineering application guidance for pipe leakage location technology.

Probabilistic Uncertainty Quantification of Borehole Thermal Resistance in Real-World Scenarios

The thermal resistance of a borehole heat exchanger (BHE) varies significantly depending on the position of the pipe legs. However, the pipe position cannot be fully controlled during its construction because of extreme slenderness of BHEs. As a result, the borehole thermal resistance (Rb) estimated from one BHE cannot represent the entire borefield. This study probabilistically quantified the uncertainty of Rb caused by the inherent uncertain characteristics through Monte Carlo simulations. The following four scenarios were considered: 1) pipe legs move along the central axis of the borehole, 2) insertion of a U-tube using spacers to maintain the shank spacing, 3) pipe legs freely located inside the borehole, and 4) considering uncertainty of the pipe location, borehole radius, and thermal conductivities of the grout and ground. The results demonstrated that the use of spacers significantly improves Rb and reduces its uncertainty range. The results of the last scenario revealed that the maximum Rb could be more than twice the minimum value. Moreover, the spatial variation of Rb according to the pipe position was systematically analyzed to clarify the dynamics of b change. The results suggest that Rb obtained through a thermal response test cannot adequately represent the entire borefield.

Friction welding of dissimilar joints copper-stainless steel pipe consist of 0.06 wall thickness to pipe diameter ratio

This paper examines dissimilar friction welding between electrolytic tough pitch copper (ETP-Cu) and stainless steel (SS) of grade 304 L for pipe joint configuration, having 0.06 wall thickness to pipe diameter ratio. The welding is performed using the continuous drive friction welding method. The welded joint is evaluated by visual inspection, leak-proof ability by helium leak detection testing, microstructure features by optical and scanning electron microscopy, energy dispersive x-ray spectroscope, x-ray diffraction patterns, tensile testing, and hardness measurements. The continuity of welding is evaluated by peripheral inspection and testing on four different locations of pipe welded joint. The results revealed that sound joints between dissimilar materials of Cu-SS are established with evidence of resistance to leak at room temperature and after cryogenic shock test. The Cu-SS pipe joint received excellent strength of 242.48 N/mm2, which is nearly 80% of ETP-Cu base material. The microstructure changes are distinctly observed at the Cu side, whereas no significant microstructure changes are observed at the SS side. The microstructure features are consisting of full dynamic recrystallization zone and partial dynamic recrystallization zone that are identified at the Cu side. However, no adverse effect of microstructure on tensile strength and hardness is observed. The weld continuity in the periphery of pipe configuration is observed at four different locations. A continuous reaction layer at four investigated locations is identified, with the presence of Cu and Fe elements at the joint interface.

Uncertainty and global sensitivity analysis on thermal performances of pipe-embedded building envelope in the heating season

Pipe-embedded building envelope, which is of particular interest to architects and engineers due to its excellent performances and invisibility characteristic, has been regarded as a potential technology for future buildings. Understanding the impacts of multiple uncertainties associated with design, construction, and operational control on its thermal performances is critical to the development of this burgeoning active insulation technology. Aiming at this goal, an in-depth uncertainty analysis (UA) and global sensitivity analysis (GSA) study was numerically conducted to investigate the influence mechanism of 12 different variables on 5 performance indicators in winter conditions. The UA results indicated that a dual-effect, i.e., better indoor thermal comfort and “zero” or even “negative” thermal load of the exterior walls, could be achieved only when relevant variables were properly selected. Due to the increase in the quantities and types of input variables, as well as the internal heat transfer process became more complicated, the importance rankings of variables obtained by two different GSA methods became different. Therefore, the treed Gaussian process method was proven to be more effective in identifying the uncertain variables. The GSA results stated that heat-source temperature, indoor set-point, charging duration, and thermal conductivity of pipe-embedded layer were the four most significant variables. For heat-source temperature and indoor set-point, there always existed an obvious mutual restriction relationship between them among all indicators except exterior surface heating loss. Meanwhile, the suggested value of the charging duration was no less than 6 h, and the optimal range of the thermal conductivity of pipe-embedded layer given by GSA was 0.5–2.75 W/m·℃. Under the blocking effect of the thermal barrier, the uncertainty of the climate zone on interior surface heating load was greatly reduced, and the climate zone was no longer a key variable affecting the cumulative subcooling duration. Besides, it was proved that the pipe spacing had a great influence on the heat accumulation inside the pipe-embedded layer, pipe location had a slight influence on interior surface heating load and exterior surface heating loss, and the pipe diameter did not influence thermal performances. From the perspective of energy density, the optimal range of the pipe spacing was 100–250 mm. Overall, this study highlighted the positive effect of the pipe-embedded system on the development of new-built and existing buildings towards zero-carbon targets, and also provided useful guidance for its further applications and investigations.

Continuous Leak Location in Gas-Filled Steel Pipe Based on Optimum Wavelet Analysis of Leak AE Signal

Abstract This study is investigates how to reconstruct the continuous leak acoustic emission (AE) signal to precisely locate the leak source on a gas-filled steel pipe based on cross-correlation location theory. Thus, in this article, the determination method for the optimum mother wavelet was proposed. The frequency distribution of the continuous leak AE event was firstly extracted through wavelet transform (WT) with optimum mother wavelet. In the considered frequency range, the WT coefficients were further used to reconstruct the raw continuous leak AE signal. The correlation-based location experiments were finally carried out to evaluate the performance of the proposed method. The results show that the location errors of the leak source were decreased by some 10 % compared with those achieved by only using the raw AE signals. Thus, improvement verifies the validity of choice of the optimum mother wavelet. Meanwhile, it is also founded that, whether the reconstructed signals or raw signals were used, the localization accuracy of the leak source using the speed of the T wave is greater than that using the speed of the L wave and theoretical acoustic speed under the same symmetry of the AE sensors with reference to the leak source. Therefore, defining the acoustic speed with the speed of the T wave was recommended to use on-site for detection of the continuous leak source on a gas-filled steel pipe.

Improvement Methods for Supply Performance in Emergency Interconnection Plans

When operating a water supply network (WSN), pipe failures and water service interruptions are inevitable. A large-scale water service interruption decreases the reliability of a WSN; therefore, an emergency interconnection plan (EIP) is adopted to prevent it. To establish an EIP involving emergency interconnection pipes, in most cases, only the operation plan is considered. However, it is required to evaluate possible interconnected supply areas (PISAs) from the EIP to achieve the purpose of the EIP. It is obvious that PISA is dependent on the structure of the WSN, elevation difference between the adjacent interconnected blocks, size and location of the emergency interconnection pipes, and inline pumping station. In this study, we categorized the reasons resulting in insufficient PISA from the EIP and suggested improvement methods such as increasing the pipe diameter, new pumping stations, adding emergency interconnection pipes, and adding pressure relief valves. To quantify the effect of the improvement methods on the performance of the EIP, we applied them to a real WSN and estimated the emergency supply rate for each improvement method by using Pressure Driven Analysis (PDA) was used as the hydraulic simulation tool. Consequently, each improvement method increased the PISA and the emergency supply rate on the network. Thus, the suggested method will be used in the design and operation of EIPs to improve their performance.

Attribute Recognition of Buried Pipes Based on Multi-Trace Phase Features Using K-means Clustering for GPR Data Interpretation

Accurate location and depth determination of underground pipes, especially the attribute recognition, are of great importance yet remake a challenging issue in municipal environments. Single-trace phase difference analysis remains a bottleneck due to its inherent and strong randomness in object identification. This paper developed a multi-trace phase difference analysis framework for ground-penetrating radar (GPR) data based on K-means cluster analysis technique and the theory of region of interest (ROI), which could serve as a new criterion for successful pipe attribute recognition. After improving signal-to-noise ratio of GPR data by using the preprocessing techniques, the connected components algorithms (CCA) based on image segmentation and morphological operation is performed to delineate the ROI. The K-means cluster analysis technique is further employed to efficiently extract the multi-trace phase statistical features for comprehensively evaluating the attributes of ROI. We verify this proposed framework by simulated GPR signals, laboratory data and field datasets. Results demonstrate that the proposed method can not only facilitate the attribute recognition of pipes, but also reduce the interpretation ambiguity of the pipe material even in the field site environment. Specifically, if the phase difference of pipe turns out to be even multiples of π, the target can be automatically identified as metallic-category pipes, whereas odd multiples of π, point to non-metallic-category pipes with a lower permittivity than that of the background. This criterion presents promising applicability in subsurface pipeline identification and attributes recognition, especially in constructing a more appropriate initial model of GPR full waveform inversion for survey in pipes.

Leakage of gasoil from side cut piping in crude distillation unit of a petroleum refinery

This paper reports failure of elbow from side cut piping after three years of refinery gasoil service and piping metallurgy was SS316L austenitic stainless steel. Systematic investigations including visual inspection coupled with laboratory studies were carried out to determine the cause of failure. The samples from failure location were examined for chemical analysis, hardness, fractography, elemental analysis and metallographic evaluation. Further, crude feedstock was evaluated as well. Various characterization studies concluded that presence of material defect encapsulated in elbow prior to start of initial distillation column (side cut piping) operation was the root cause of failure. Localized stresses induced from internal pressure act on remaining wall thickness have lead to brittle fracture and resulted in gasoil leakage. The existence of material defect in failed elbow prior to initial operation had revealed poor pre-commissioning inspection practice. The origination of detected material defect was discussed and similar leakages shall be avoided by defect free piping components provided with proper support system at critical piping locations. The results in this article intended for petroleum refinery piping/energy pipeline operators for use of qualified piping components at critical locations especially during plant/piping commissioning stage.

The potential kimberlite field of the Kafur-Masari-Malumfashi area, northwestern Nigeria – evidence from integrated regional geophysical signatures

This study investigates the distribution of potential kimberlitic pipes in the Kafur-Masari-Malumfashi region of northwestern Nigeria from satellite gravity and regional aeromagnetic data beyond the Kafur kimberlite pipe discovered previously. The interpretation indicates the presence of some roughly circular to oval shaped analytical signal anomalies which coincide with locations of concealed kimberlitic pipes. These results confirm the Kafur kimberlite and delineate six other suspected kimberlitic pipes. The integrated 2D model images and the signatures of the anomalies obtained allow us to interpret and confirm the field responses as possible multiple kimberlitic pipe intrusions within the basement. Thus suggesting that the region is a potential kimberlite field and represents targets for follow-up surveys.

Impact of Climate Change on Flood Hazard at Airports on Pacific Islands: A Case Study of Faleolo International Airport, Samoa

Climate change is believed to have increased the intensity and frequency of heavy rainfall, and also to have caused sea level rises over this century and beyond. There is widespread concern that small-island nations are particularly vulnerable to increasing risk of inland flood due to such climate change. Understanding the impact of climate change on flood hazard is of great importance for these countries for the development of better protection and adaptation strategies. This study conducted a case study focusing on the impact of climate change on flood hazard at Faleolo International Airport (FIA), Samoa. FIA is a typical small islands airport, located on the lowland along the coast fronted by a fringing reef. Annual maximum daily rainfalls for different return periods were first estimated for the present and future climate around FIA. The estimated rainfalls were input as the forcing of a two-dimensional flood inundation model to investigate the flooding behavior and effectiveness of probable drainage systems. Results showed that a part of the runway can be inundated under heavy rainfall. Construction of drainage pipes significantly contributes to reducing the flood hazard level. Sensitivity analysis showed that the astronomical tide level has relatively little influence on the performance of the drainage system, while the combination of sea level rise and the sea level anomaly induced by stormy waves on the fringing reef could have non-negligible impacts on the drainage system. Location of the drainage pipe is also important to effectively mitigate flooding. The time-concentration of torrential rainfall may also significantly impact the overall performance of the drainage system.

Experimental and Numerical Investigations of Multi-leaks Detection in a Nonhomogenous Pipeline System

This paper focuses on an experimental procedure to localize multiple leaks in a nonhomogenous hydraulic pipeline system made up of three portions of two different materials. Then, an experimental setup originally designed for water hammer study was modified and adapted for leak detection using transients. Two leaks were made in some particular locations in the main pipe and a transient event through a rapid closure of a downstream valve was created. To mimic common practical issues that may be encountered, three main leakage cases were considered; a single leak, two simultaneous leaks and two successive leaks (i.e., one leak that appears followed by an abrupt appearance of a second leak after a period of time). Leaks were experimentally localized by analyzing obtained pressure signals in the excitation point. Results were validated through comparison with numerical ones obtained using the method of characteristics. Additionally, a novel formula to localize the second leak in a successive leaks scenario was presented and its accuracy was confirmed for our test case. Experimental techniques presented in this paper and performed on a test bench at lab scale can be extended and tested on large scale hydraulic pipeline systems.

Seismic detection and characterization of a man-made karst analog — A feasibility study

At the site of a water drainage shaft on the campus of Qatar University that serves as a man-made karst analog, two seismic imaging techniques were adapted to use resonant scattered waves recorded during active-source seismic surveys and during passive ambient-noise surveys. Data acquisition included two seismic transmission surveys that encompassed the shaft and a passive ambient-noise survey that extended across the top of the shaft. Seismic imaging of band-pass-filtered resonance waves correctly estimated the location and dimension of the shaft. Furthermore, the method detected the presence and the location of a horizontal drainage pipe and gravel bed connecting neighboring water shafts. Ambient-noise data were analyzed by computing amplitude values of the seismic records in spectral passbands. The results indicated an amplification of seismic amplitudes above the shaft for low-frequency passbands and a sharp decrease in amplitude values for high-frequency passbands. The high- and low-amplitude values displayed as a function of the receiver position allowed for accurate detection and location of the shaft in space. Ground truthing of the imaging results confirmed the accuracy of the seismic techniques, whereas numerical modeling supported the interpretation of the ambient-noise data. The techniques used do not require knowledge of the seismic velocities in the subsurface, but they depend on a priori information about the approximate location of the target.

EVALUATION OF AN AERATION SYSTEM FOR FISH CULTURED IN CLOSED SYSTEMS

This study was Carried out at Central Laboratory for Aquaculture Research in (2017), to determine the best levels of oxygen supply on growth performance and oxidation status of Nile tilapia (Oreochromis nilollcus), Grey mullet (Mugil cephalus) and Common carp (Cyprinus carpio) fingerlings stocked at (85%, 10% and 5%), respectively, total of fingerlings with initial weight of weighting (10±0.30) g/fish were reared in tanks i.e., supplied with normal water, air pumping and filtration system applied throughout the experimental period, with 3 replicates to evaluate the effect of perforated pipe location i.e., 0 and 100 cm from the bottom of tanks, distance between holes such as : 10cm, air pressure levels i.e., 0.2 and 0.4 bar on water quality, growth rate of fish and net profit. The obtained results revealed that the perforated pipe located at 100 cm with distance between holes such as: 10 cm and air pressure (P) of 0.4 bar gave the highest average of water quality like pH (7.72±.30 and 8.18±2.48 mg/l), dissolved oxygen (7.42±.29 and 8.38±2.54 mg/l), water temp (27C ±.81), ammonia (0.29±.01 and 0.28±.08 mg/l), total hardness (171.4±6.85 and 170.9±51.97), total alkalinity (165.3 ± 6.61 and 180.7±54.95 mg/l), nitrate (0.01±.0004 and 0.01±.003), nitrite (0.11±.004 and 0.12±.03) for air pressure levels (0.2 and 0.4) bar respectively. Compared with control result which were 6.7±.30, 4.45±2.54, 0.32±01, 25.0±2.16, 340±2.71, 370±12.7, 0.12±008 and 0.40±0.001 for pH, dissolved oxygen, water temp, ammonia, total hardness, total alkalinity, nitrate and nitrite. The highest average of growth rate values; final body weight (74.9±22.77, 77.4±1.16 and71.9±3.59 g), final body length (19.2±5.83, 18.2±.27 and 16.4±0.32 cm), final body weight gain (5±0.20, 4.4±0.06and 4.6±0.09g), final condition factor (1.36±0.05, 1.38±0.23and 2.61±0.26g/cm3) and final feed conversion ratio (1.56±0.47, 1.62±0.02 and1.68 ± 0.03 g/fish), Final SGR were (1.93±0.58, 1.68±0.02 and 2.0 ±0.04%) and final survival rate (%) were (91.8±2.9 , 88.9±2.6 and 90.2±1.2) for Nile tilapia (Oreochromis nilollcus), Grey mullet (Mugil cephalus) and Common carp (Cyprinus carpio) and distances between holes of 10 cm and pressure levels of 0.4 bar Respectively. Finally, it could be concluded that, under the similar conditions: The Air pressure (P) level of 0.4 bar, perforated pipe location of 100 cm and distance between holes 10 cm were the best parameters where it gave Significantly high water quality, growth performance (P<0.0001) and survival of fish (P<0.0001) was observed in aerated tanks as compared with the non-aerated tanks.