Journal articles: 'Structural blockages'

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Bin Ali, M. T., K. V. Horoshenkov, and S. J. Tait. "Rapid detection of sewer defects and blockages using acoustic-based instrumentation." Water Science and Technology 64, no. 8 (October 1, 2011): 1700–1707. http://dx.doi.org/10.2166/wst.2011.183.

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Sewer flooding incidents in the UK are being increasingly associated with the presence of blockages. Blockages are difficult to deal with as although there are locations where they are more likely to occur, they do occur intermittently. In order to manage sewer blockage pro-actively sewer managers need to be able to identify the location of blockages promptly. Traditional closed-circuit television (CCTV) inspection technologies are slow and relatively expensive so are not well suited to the rapid inspection of a network. This is needed if managers are to be able to address sewer blockages pro-actively. This paper reports on the development of an acoustic-based sensor. The sensor was tested in a full scale sewer pipe in the laboratory and it was shown that it is able to find blockages and identify structural aspects of a sewer pipe such as a manhole and lateral connection. Analysis of the received signal will locate a blockage and also provide information on its character. The measurement is very rapid and objective and so inspections can be carried out at much faster rates than using existing CCTV technologies.

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Altarabsheh, Ahmad, Mario Ventresca, Amr Kandil, and Dulcy Abraham. "Markov chain modulated Poisson process to stimulate the number of blockages in sewer networks." Canadian Journal of Civil Engineering 46, no. 12 (December 2019): 1174–86. http://dx.doi.org/10.1139/cjce-2018-0104.

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Blockage failure is the most common type of operational failure in sewer networks that can cause loss of service and flooding, which can result in environmental pollution, health risks, property damage, and traffic disruption. There are currently very few blockage prediction models that are either deterministic in nature or depend only on static factors in predicting blockages. This study aims to overcome these drawbacks in the current blockage prediction models and proposes a methodology that aims to predict the expected number of blockages in sewer networks as a function of pipe conditions (dynamic variable) and pipe physical attributes (static variables) using a Markov chain modulated Poisson process modeling framework. The framework is applied to case study sewer network in the city of Sahab, Jordan, that contains information about the pipes’ physical attributes and their current condition. Bayesian analysis is then performed to evaluate the proposed framework.

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Rosin, T. R., Z. Kapelan, E. Keedwell, and M. Romano. "Near real-time detection of blockages in the proximity of combined sewer overflows using evolutionary ANNs and statistical process control." Journal of Hydroinformatics 24, no. 2 (March 1, 2022): 259–73. http://dx.doi.org/10.2166/hydro.2022.036.

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Abstract Blockages are a major issue for wastewater utilities around the world, causing loss of service, environmental pollution, and significant clean-up costs. Increasing telemetry in combined sewer overflows (CSOs) provides the opportunity for near real-time data-driven modelling of wastewater networks. This paper presents a novel methodology, designed to detect blockages and other unusual events in the proximity of CSO chambers in near real-time. The methodology utilises an evolutionary artificial neural network (EANN) model for short-term CSO level predictions and statistical process control (SPC) techniques to analyse unusual level behaviour. The methodology was evaluated on historic blockage events from several CSOs in the UK and was demonstrated to detect blockage events quickly and reliably, with a low number of false alarms.

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DREBLOW, KERSTIN, NIKOLINA KALCHISHKOVA, and KONRAD J. BÖHM. "KINESIN BYPASSING BLOCKAGES ON MICROTUBULE RAILS." Biophysical Reviews and Letters 04, no. 01n02 (April 2009): 139–51. http://dx.doi.org/10.1142/s1793048009000958.

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Kinesins are motor proteins which convert the chemical energy of ATP into mechanical energy to move along proteinaceous microtubule rails and to transport different cargoes to defined intracellular destinations. It is well documented that following the track of a single protofilament is the thermodynamically most effective mechanism of kinesin movement along microtubules. However, the question arises what happens when a kinesin molecule encounters a hindrance along the protofilament. The present study describes a simple, cell-free approach which enables to study the effects of structural blockages on kinesin-based transport. This experimental approach uses dimeric conventional kinesin moving nanometre-sized gold beads along immobilized microtubules whose surface has been irreversibly decorated by blocking proteins. We demonstrated that the continuous bead transport temporarily stopped at sites of blockages, but usually continued after a certain resting time. Our results suggest that single dimeric kinesin molecules are able to change to another protofilament if the next tubulin dimer where the second head should bind is blocked. A bypassing mechanism is discussed which is considered to be one fundamental prerequisite to realize a kinesin-mediated cargo-transport along microtubules over long distances, required for e.g., the fast axonal transport in motor neurons.

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Marlow, D. R., F. Boulaire, D. J. Beale, C. Grundy, and M. Moglia. "Sewer Performance Reporting: Factors That Influence Blockages." Journal of Infrastructure Systems 17, no. 1 (March 2011): 42–51. http://dx.doi.org/10.1061/(asce)is.1943-555x.0000041.

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Martins, Nuno M. C., Dídia I. C. Covas, Silvia Meniconi, Caterina Capponi, and Bruno Brunone. "Characterisation of low-Reynolds number flow through an orifice: CFD results vs. laboratory data." Journal of Hydroinformatics 23, no. 4 (May 3, 2021): 709–23. http://dx.doi.org/10.2166/hydro.2021.101.

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Abstract Pressurised pipe systems transport fluids daily over long distances and sediment deposits are responsible for narrowing the cross-sectional area of the pipe. This reduces the carrying capacity in gravity pipes and increases the energy consumption in rising mains. As partial blockages do not give rise to any external evidence, they are considered the most insidious fault occurring in pipe systems. Thus, the refinement of reliable techniques for detecting partial blockages at an early stage is of great interest to water utilities. This paper presents a computational fluid dynamics (CFD)-based analysis of the steady-state flow through a sharp-edged orifice which corresponds to the most straightforward partial blockage feature in a pipe. The main motivation is the fact that the interaction between pressure waves and a partial blockage – on which Transient Test-Based Techniques for fault detection are based – is strongly influenced by the pre-transient conditions at the partial blockage. The refined CFD model has been validated by considering experimental data selected from the literature. The comparison of obtained results demonstrates good performance of the numerical model. This authorised exploring in detail the features of the flow through the orifice as a necessary premise to its use within the successive transient analysis.

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Irshad, Ali, Libo Zhu, Bhatti Huma, Aziz Asad, and Quanjun Liu. "Electrical Sensing and Discrimination of Different States of Myoglobin Through Solid-State Nanopore." Nanoscience and Nanotechnology Letters 11, no. 9 (September 1, 2019): 1271–80. http://dx.doi.org/10.1166/nnl.2019.3002.

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Proteins are structurally dynamic macromolecules that exist in various conformations of similar energies. The function of protein usually depends upon its structural formation which is often induced by ligand binding. These conformational changes are of great interest in proteomics and biochemistry. In this work, we extended our knowledge to effectively detect structural perturbations of Mb (Myoglobin) in the presence of OA (Oleic acid) by using a ∼20 nm (diameter) silicon-nitride (Si3N4) nanopore. This interaction can be either specific or non-specific depending upon the concentration of OA in Mb solution. Results of nanopore relied on the succession of current blockages as characterized by their duration, amplitude and event's number. In order to detect the interaction, three kinds of experiments were performed under three different OA/Mb ratios and various event readouts were obtained. First of all, we took the volume ratio of OA/Mb as 4:1 and found that values of dwell time (td ) and current blockage (ΔIb ) were similar to Mb (only) translocation. Secondly, giving an increment in the volume ratio of OA/Mb to 10:1 resulted in a significant increase in dwell time (td ) and current blockage (ΔIb ) level. Furthermore, a dramatic decrease in amplitude of ionic current blockage (ΔIb ) and dwell time (td ) was observed at the ratio 20:1 of OA/Mb which indicated that OA/Mb interaction can cause structural instability of myoglobin. This may also disturb charge distributions on amino acid residues which results in variation of above-mentioned parameters. This approach of nanopore sensing can be extensively employed in screening FABPs (Fatty acid binding proteins) and protein conformational studies.

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Schmitz, Joseph, and Kelly Whitworth. "Collaborative Self-assessment in the Academy: Coping with Structural Blockages to Self-discovery." Communication Education 51, no. 2 (April 2002): 134–51. http://dx.doi.org/10.1080/03634520216507.

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9

Louis, Skayu. "Sensory access at sxxnitk: Blockages, fluidities and futures." Journal of Environmental Media 2, no. 1 (November 1, 2021): 9.1–9.16. http://dx.doi.org/10.1386/jem_00057_1.

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In the summer of 2020, tensions rose at sxxnitk, an ancestral fishing village site, for the Syilx Okanagan Peoples due to a landowner seeking to exclude access to a portion of qawsitk (Okanagan) river. Access to sxxnitk is integral for Syilx Nation building and realizing embodied relationships with the Salmon peoples, which have been hindered by a multiplicity of factors that almost removed salmon completely from the Territory. Sensory access throughout the village site is not only important to rebuild relations with the salmon, but also those with the place itself. sxxnitk remains a portal of relationality with waterscapes from the high mountains into the Pacific Ocean. Waterscapes connect peoples, polities and humans/more-than-humans throughout their spaces of motion. In an era of altered river pathways, intensified relationships grounded in particular waterscapes can help to build relations beyond the structural blockages that fragment the flow of the river and its ecologies. These relationships are important for collaborative healing throughout the watershed. Renewing relations with ecologies of flow and motion bring to question the fragmented jurisdictions that seek to carve up Indigenous territories.

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Podd, F. J., M. T. B. Ali, K. V. Horoshenkov, A. S. Wood, S. J. Tait, J. C. Boot, R. Long, and A. J. Saul. "Rapid sonic characterisation of sewer change and obstructions." Water Science and Technology 56, no. 11 (December 1, 2007): 131–39. http://dx.doi.org/10.2166/wst.2007.741.

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This paper reports on the development of a low-cost, rapidly deployable sensor for surveying live sewers for blockages and structural failures. The anticipated cost is an order of magnitude lower than current techniques. The technology is based on acoustic normal model decomposition, The instrument emits short coded acoustic signals which are reflected from any sewer wall defect. The acoustic signals can be short Gaussian pulses or longer sinusoidal sweeps and pseudo-random noise. The processing algorithms used on the reflected signal can predict the extent and geometry of the pipe deformation, and the locations and approximate size of common blockages. The effect of the water level on the frequency of the fundamental mode has also been investigated. It is shown that the technique can be adapted to work reliably in relatively large 600 mm diameter sewer pipes.

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Mohapatra, Pranab K., and M. Hanif Chaudhry. "Frequency responses of single and multiple partial pipeline blockages." Journal of Hydraulic Research 49, no. 2 (April 2011): 263–66. http://dx.doi.org/10.1080/00221686.2010.544887.

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12

Wang, Ping, Steven L. Jones, Saravanan Gurupackiam, and Li Wang. "Novel Cell Transmission Model–Based Simulations of Left-Turn Blockages inside Intersections." Transportation Research Record: Journal of the Transportation Research Board 2390, no. 1 (January 2013): 60–67. http://dx.doi.org/10.3141/2390-07.

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Yan, X. F., H. F. Duan, X. K. Wang, M. L. Wang, and P. J. Lee. "Investigation of Transient Wave Behavior in Water Pipelines with Blockages." Journal of Hydraulic Engineering 147, no. 2 (February 2021): 04020095. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0001841.

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Yazdi, J. "Improving Urban Drainage Systems Resiliency Against Unexpected Blockages: A Probabilistic Approach." Water Resources Management 32, no. 14 (August 11, 2018): 4561–73. http://dx.doi.org/10.1007/s11269-018-2069-3.

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15

Li, Shicheng, James Yang, and Qiulin Li. "Numerical Modelling of Air-Water Flows over a Stepped Spillway with Chamfers and Cavity Blockages." KSCE Journal of Civil Engineering 24, no. 1 (December 4, 2019): 99–109. http://dx.doi.org/10.1007/s12205-020-1115-x.

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16

Fologea, Daniel, Eric Krueger, Steve Rossland, Sheenah Bryant, Wylie Foss, and Tyler Clark. "Cationic Polymers Inhibit the Conductance of Lysenin Channels." Scientific World Journal 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/316758.

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The pore-forming toxin lysenin self-assembles large and stable conductance channels in natural and artificial lipid membranes. The lysenin channels exhibit unique regulation capabilities, which open unexplored possibilities to control the transport of ions and molecules through artificial and natural lipid membranes. Our investigations demonstrate that the positively charged polymers polyethyleneimine and chitosan inhibit the conducting properties of lysenin channels inserted into planar lipid membranes. The preservation of the inhibitory effect following addition of charged polymers on either side of the supporting membrane suggests the presence of multiple binding sites within the channel's structure and a multistep inhibition mechanism that involves binding and trapping. Complete blockage of the binding sites with divalent cations prevents further inhibition in conductance induced by the addition of cationic polymers and supports the hypothesis that the binding sites are identical for both multivalent metal cations and charged polymers. The investigation at the single-channel level has shown distinct complete blockages of each of the inserted channels. These findings reveal key structural characteristics which may provide insight into lysenin’s functionality while opening innovative approaches for the development of applications such as transient cell permeabilization and advanced drug delivery systems.

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Tariq, Mosammat Tahnin, Aidin Massahi, Rajib Saha, and Mohammed Hadi. "Combining Machine Learning and Fuzzy Rule-Based System in Automating Signal Timing Experts’ Decisions during Non-Recurrent Congestion." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 6 (May 18, 2020): 163–76. http://dx.doi.org/10.1177/0361198120918248.

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Events such as surges in demand or lane blockages can create queue spillbacks even during off-peak periods, resulting in delays and spillbacks to upstream intersections. To address this issue, some transportation agencies have started implementing processes to change signal timings in real time based on traffic signal engineers’ observations of incident and traffic conditions at the intersections upstream and downstream of the congested locations. Decisions to change the signal timing are governed by many factors, such as queue length, conditions of the main and side streets, potential of traffic spilling back to upstream intersections, the importance of upstream cross streets, and the potential of the queue backing up to a freeway ramp. This paper investigates and assesses automating the process of updating the signal timing plans during non-recurrent conditions by capturing the history of the responses of the traffic signal engineers to non-recurrent conditions and utilizing this experience to train a machine learning model. A combination of recursive partitioning and regression decision tree (RPART) and fuzzy rule-based system (FRBS) is utilized in this study to deal with the vagueness and uncertainty of human decisions. Comparing the decisions made based on the resulting fuzzy rules from applying the methodology with previously recorded expert decisions for a project case study indicates accurate recommendations for shifts in the green phases of traffic signals. The simulation results indicate that changing the green times based on the output of the fuzzy rules decreased delays caused by lane blockages or demand surge.

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Zhang, Chunjun, and Xila Liu. "A Large Increment Method for Material Nonlinearity Problems." Advances in Structural Engineering 1, no. 2 (April 1997): 99–110. http://dx.doi.org/10.1177/136943329700100202.

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In the case of small deformation, cumulative errors and time consumption are the crux blocking the application of flow theory for material nonlinearity problems. To overcome these blockages, a new algorithm is proposed in the present paper. Different from traditional methods, the theory of generalized inverse of matrix and a new optimization approach are introduced to give full play of the force method. As one of the main advantages, parallel computation process is used to replace the step by step solution process. Time consumption are therefore reduced and cumulative errors suppressed in essence.

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Che, T. C., H. F. Duan, P. J. Lee, B. Pan, and M. S. Ghidaoui. "Transient Frequency Responses for Pressurized Water Pipelines Containing Blockages with Linearly Varying Diameters." Journal of Hydraulic Engineering 144, no. 8 (August 2018): 04018054. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0001499.

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Okwori, E., M. Viklander, and A. Hedström. "Spatial heterogeneity assessment of factors affecting sewer pipe blockages and predictions." Water Research 194 (April 2021): 116934. http://dx.doi.org/10.1016/j.watres.2021.116934.

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Pecci, Filippo, Panos Parpas, and Ivan Stoianov. "Sequential Convex Optimization for Detecting and Locating Blockages in Water Distribution Networks." Journal of Water Resources Planning and Management 146, no. 8 (August 2020): 04020057. http://dx.doi.org/10.1061/(asce)wr.1943-5452.0001233.

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Gao, Bowen, Decun Dong, Yusen Wu, and Dongxiu Ou. "Macroscopic Real-Time Timetable Rescheduling Approach for High-Speed Railway under Complete Blockages Using a Three-Stage Algorithm." Transportation Research Record: Journal of the Transportation Research Board 2676, no. 3 (November 2, 2021): 535–50. http://dx.doi.org/10.1177/03611981211052960.

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The rescheduling of train timetables under a complete blockage is a challenging process, which is more difficult when timetables contain lots of trains. In this paper, a mixed integer linear programming (MILP) model is formulated to solve the problem, following the rescheduling strategy that blocked trains wait inside the stations during the disruption. When the exact end time of the disruption is known, trains at stations downstream of the blocked station can depart early. The model aims at minimizing the total delay time and the total number of delayed trains under the constraints of station capacities, activity time, overtaking rules, and rescheduling strategies. Because there are too many variables and constraints of the MILP model to be solved, a three-stage algorithm is designed to speed up the solution. Experiments are carried out on the Beijing–Guangzhou high-speed railway line from Chibibei to Guangzhounan. The original timetable contains 162 trains, including 29 cross-line trains and 133 local trains. The simulation results show that our model can handle the optimization task of the timetable rescheduling problem very well. Compared with the one-stage algorithm, the three-stage algorithm is proved to greatly improve the solving speed of the model. All instances can get a better optimized disposition timetable within 450 to 600 s, which is acceptable for practical use.

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Li, Hua, Yifeng Wang, Jingyu Zhang, Liangpeng Wan, Qiao Jiang, Hongyue Pan, Yuanyuan Hu, and Kun Wang. "Model Test Research on the Influence of Gate Blocking in Siltation Environment." Advances in Civil Engineering 2021 (March 10, 2021): 1–9. http://dx.doi.org/10.1155/2021/6674534.

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Aiming at the clogging problems encountered in the operation of deep-hole gates in high water level reservoirs and dams, this paper carried out a model test study on the influence of different materials and different siltation environments on the lifting of the gates and analyzed the rules of the effects of blockages in different siltation environments. An analysis model of the pull-out force of the gate (blocked object) considering the siltation environment was proposed in an innovative way and the similarity ratio relationship was verified. The results of the study show that (1) the size and time of the siltation and other factors have a significant influence on the pulling force of the blocked object. It increases with the increase of the siltation area. The longer the siltation goes on, the greater the pulling force will be. (2) As the similarity ratio n increases, the calculation result of the analysis model is closer to the target value n 2 and it indicates that the theoretical model is reliable. The research results of this paper can provide certain guidance for deep-hole siltation dispatch to ensure project safety.

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Che, T. C., H. F. Duan, B. Pan, P. J. Lee, and M. S. Ghidaoui. "Energy Analysis of the Resonant Frequency Shift Pattern Induced by Nonuniform Blockages in Pressurized Water Pipes." Journal of Hydraulic Engineering 145, no. 7 (July 2019): 04019027. http://dx.doi.org/10.1061/(asce)hy.1943-7900.0001607.

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Carriveau, E. C., R. E. Baddour, and G. A. Kopp. "The entrainment envelope of dye-core vortices at submerged hydraulic intakes." Canadian Journal of Civil Engineering 29, no. 3 (June 1, 2002): 400–408. http://dx.doi.org/10.1139/l02-015.

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Each winter in Canada, operational difficulties are encountered at various water works resulting from intake blockages caused by frazil ice entrainment. In a lake setting, frazil is a surface phenomenon, the strong downward current produced by a swirling flow, with an intake vortex present, provides a mechanism by which frazil is transported from the water surface to the submerged intake below. Laboratory experiments were conducted to study the entrainment envelope associated with swirling and non-swirling flows into submerged water intakes. Three-dimensional velocity measurements were made with an acoustic Doppler velocimeter. The results clearly show that the entrainment envelope for swirling flow is several times larger than that for non-swirling flow. This paper details, for a given set of conditions, the differences in the non-swirling and swirling flow entrainment envelopes and emphasizes the potential difficulties with frazil ice that vortices can cause at intakes.Key words: vortex, dye-core vortex, submerged hydraulic intake, entrainment envelope, three-dimensional velocity measurements, acoustic Doppler velocimeter.

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Fabian, Joshua J., and Gabriel E. Sánchez-Martínez. "Simulation-Based Comparison of Holding Strategies for a Multibranch Light Rail Service." Transportation Research Record: Journal of the Transportation Research Board 2648, no. 1 (January 2017): 23–32. http://dx.doi.org/10.3141/2648-03.

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Light rail transit services face many operational challenges, such as capacity constraints, mixed-traffic interference, and branch junctions. The service plans developed for these lines typically specify a precise schedule for each vehicle. Running time and demand variability, special events, and incidents make it challenging to adhere to schedules. Operators can enact real-time control actions to mitigate delays. This research compared the effectiveness of schedule- and headway-based holding strategies applied en route and at terminals (i.e., dispatching) on a simulation model of the Massachusetts Bay Transportation Authority Green Line, a four-branch light rail line. The effects of control point placement at terminals, along branches, along a central trunk, and in combinations of these three were studied, as were the effects of limiting holding at midroute stations. Holding strategies were compared on the basis of service and passenger-oriented performance. Headway-based holding was found to be a more effective method for ensuring that passengers experienced reasonable wait times within scheduled headways. Holding at terminals appeared to be the most beneficial to passengers; additional holding along the branches and limited holding along the trunk were shown to enhance these benefits. Holding only within the trunk of a multibranch service worsened service because of blockages from held trains.

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Cai, Yonghua, Di Wu, Jingming Sun, and Ben Chen. "The effect of cathode channel blockages on the enhanced mass transfer and performance of PEMFC." Energy 222 (May 2021): 119951. http://dx.doi.org/10.1016/j.energy.2021.119951.

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Pulido, Eliana Soriano, Carlos Valencia Arboleda, and Juan Pablo Rodríguez Sánchez. "Study of the spatiotemporal correlation between sediment-related blockage events in the sewer system in Bogotá (Colombia)." Water Science and Technology 79, no. 9 (May 1, 2019): 1727–38. http://dx.doi.org/10.2166/wst.2019.172.

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Abstract The planning and scheduling of maintenance operations of large conventional sewer systems generate a complex decision-making environment due to the difficulty in the collection and analysis of the spatiotemporal information about the operational and structural condition of their components (e.g. pipes, gully pots and manholes). As such, water utilities generally carry out these operations following a corrective approach. This paper studies the impact of the spatiotemporal correlation between these failure events using Log-Gaussian Cox Process (LGCP) models. In addition, the association of failure events to physical and environmental covariates was assessed. The proposed methods were applied to analyze sediment-related blockages in the sewer system of an operative zone in Bogotá (Colombia). The results of this research allowed the identification of significant covariates that were further used to model spatiotemporal clusters with high sediment-related failure risk in sewer systems. The LGCP model proved to be more accurate in comparison to those models that build upon a fundamental assumption that a failure is equally likely to occur at any time regardless of the state of the system and the system's history of failures (i.e. a homogeneous Poisson process model).

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Usman, Kristianto, Michael Peter Nicholas Burrow, Gurmel Singh Ghataora, and Manu Sasidharan. "Using Probabilistic Fault Tree Analysis and Monte Carlo Simulation to Examine the Likelihood of Risks Associated with Ballasted Railway Drainage Failure." Transportation Research Record: Journal of the Transportation Research Board 2675, no. 6 (April 19, 2021): 70–89. http://dx.doi.org/10.1177/0361198120982310.

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Inadequate track drainage can lead to a variety of issues, including flooding, accelerated track degradation, and progressive or sudden failure of railway track, slope, or embankment. These can result in unplanned track maintenance, additional passenger travel costs, and damage to third party property. However, railway drainage asset management is challenging because it involves the consideration of large interconnected assets, limited maintenance budgets, and unknown failure probabilities. To address this issue, this paper introduces a risk-informed approach for railway drainage asset management that uses fault tree analysis to identify the factors that contribute to railway drainage flood risk and quantifies the likelihood of the occurrence of these factors using Monte Carlo simulation. This rational approach enables drainage asset managers to evaluate easily the factors that affect the likelihood of railway track drainage failure, thereby facilitating the prioritization of appropriate mitigation measures and in so doing improve the allocation of scarce maintenance resources. The analysis identified 46 basic and 49 intermediate contributing factors associated with drainage failure of ballasted railway track (undesired event). The usefulness of the approach is demonstrated for three sites on the UK railway network, namely, Ardsley Tunnel, Clay Cross Tunnel, and Draycott. The analysis shows that the Clay Cross Tunnel had the highest probability of drainage failure and should be prioritized for maintenance over the other two sites. The maintenance required should focus on blockages because of vegetation overgrowth or debris accumulation.

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Duan, Huan-Feng, Bin Pan, Manli Wang, Lu Chen, Feifei Zheng, and Ying Zhang. "State-of-the-art review on the transient flow modeling and utilization for urban water supply system (UWSS) management." Journal of Water Supply: Research and Technology-Aqua 69, no. 8 (October 22, 2020): 858–93. http://dx.doi.org/10.2166/aqua.2020.048.

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Abstract In the context of smart city development and rapid urbanization worldwide, urban water supply system (UWSS) has been of vital importance to this process. This paper presents a comprehensive review on the transient flow research for UWSS management. This review consists of two aspects as follows. The first aspect is about the development and progress of current transient theory, including transient flow models, unsteady friction and turbulence models, and numerical simulation methods. The other aspect is about the utilization and application of transient-based methods for effective UWSS diagnosis and management, including leakage, discrete and extended partial blockages, unknown branch, and other defects in water pipelines. A total of 228 publications have been reviewed and analyzed in this paper. In addition to the state-of-the-art progress and achievement of the research on transients, the advances and recommendations of future work in this field are also discussed for the development and management of next-generation smart UWSS in the paper.

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Gevers, Camille, Helena F. M. W. van Rijswick, and Julia Swart. "Peasant Seeds in France: Fostering A More Resilient Agriculture." Sustainability 11, no. 11 (May 28, 2019): 3014. http://dx.doi.org/10.3390/su11113014.

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The profitability of the French agricultural sector has fallen over the last two decades, leading to the suggestion of a “rupture in technical progress”. Additionally, the intellectual property regime in force has contributed to the erosion of the cultivated biodiversity, limiting plant resiliency to climate change and other hazards. In the face of these challenges, agroecological farming practices are a viable alternative. This paper investigates the positive and negative aspects associated with the development of alternative seed procurement networks in France. The findings indicate that peasant seed networks can effectively contribute to overcoming many of the structural blockages with which French agriculture is confronted, but that yield concerns; higher information and supervisory costs, as well as the unfavourable legislative context, constitute key challenges to their development. However, these could be partially or totally eliminated if adequate policies are implemented. In this regard, the recommendations are to: (i) strengthen the dialogue with farmers in the shaping of policies related to the use of plant genetic resources; (ii) abrogate the “obligatory voluntary contribution” on farm-saved seeds; (iii) diversify the collection of Centres for Biological Resources, increase their number, and democratize their access; (iv) harmonize the French and European regime on intellectual property; and (v) encourage participatory research.

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Nawir, Daud, and Achmad Zultan Mansur. "Effects of HDPE Utilization and Addition of Wetfix-Be to Asphalt Pavement in Tropical Climates." Civil Engineering Journal 8, no. 8 (August 1, 2022): 1665–78. http://dx.doi.org/10.28991/cej-2022-08-08-010.

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Plastic Waste (PW) is one of the primary sources of pollution, leading to drainage system blockages, thereby causing floods and road pavement damage. One of the major ways to reduce pollution due to plastic waste and excessive exploitation of natural resources is through the development of HDPE. It is also important to reduce damage to road pavement structures by improving the quality of the asphalt used during construction. Therefore, this research aims to analyze the effects of using HDPE shale, an ecologically friendly material, and the addition of Wetfix-Be to asphalt pavements in tropical climates. The study results showed that 5.75% of the OAC asphalt using plastic waste raises the stability value and meets the specification requirements. Specimens of AC-WC concrete asphalt mixture were also tested by immersing them in fresh and seawater for 0.5, 24, 72, and 96 hours. In conclusion, using HDPE plastic waste and Wetfix-Be keeps the AC-WC concrete asphalt mixture stable. Doi: 10.28991/CEJ-2022-08-08-010 Full Text: PDF

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Konys, J., W. Krauss, and N. Holstein. "Aluminum-Based Barrier Development for Nuclear Fusion Applications." Corrosion 67, no. 2 (February 1, 2011): 026002–1. http://dx.doi.org/10.5006/1.3553931.

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Abstract In the helium-cooled lead-lithium (HCLL) design concept for blanket structures of a future fusion power plant, the eutectic Pb-15.7Li alloy is used as a liquid tritium breeder and is in direct contact with the structural material, e.g., ferritic-martensitic steels. Compatibility tests showed that a high corrosion attack appears and that the dissolved steel elements like Fe and Cr form precipitates, with a high risk of system blockages. Therefore, coatings as corrosion barriers are required for a reliable plant operation. Because of safety reasons, a distinct permeation reduction of the tritium, produced in the Pb-Li alloy by nuclear reactions, into the environment has to be limited, too. Previous developments already showed that Al-based coatings can perform very well as anti-corrosion and tritium permeation (T-permeation) reduction barriers in a PbLi environment. However, industrially relevant coating technologies for fusion application are still missing and/or cannot fulfil low activation criteria. Electrochemical deposition processes are highly flexible and used widely for the production of functional coatings, e.g., for corrosion protection. Nevertheless, because of its unique electrochemistry, Al cannot be deposited from water-based systems. Therefore, the development of two different Al coating processes from nonaqueous systems was initiated and proofed by the successful generation of protective and reproducible scales after heat treatment.

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Shevchenko, A. P., V. G. Kislyakov, B. W. Dvoskin, A. S. Vergun, I. A. Manachyn, V. P. Petrusha, and S. A. Shevchenko. "Stages of scientific and applied activities of the department of external processing of the iron of ISI NANU." Fundamental and applied problems of ferrous metallurgy, no. 33 (2019): 87–97. http://dx.doi.org/10.52150/2522-9117-2019-33-87-97.

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The history of the creation and development of the research unit of the Iron and Steel Institute, the department of after-furnace treatment of cast iron is presented. From 1939 to 1983, this structural unit of the ISI was headed by Doctor of Technical Sciences, Professor Natalya Aleksandrovna Voronova, then for 34 years, until 2017, the student and associate of N.A. Voronova – Doctor of Technical Sciences, Professor Shevchenko A.F., from 2017 to the present, the department is headed by Kislyakov V.G. During this period, a set of scientific research and development has provided an opportunity for the department staff to defend 3 doctoral and 16 master's theses. Two employees of the department were awarded the academic title of professor, and ten – senior research assistant. The evolution of the technological process and equipment for the processing of cast iron by granular magnesium in ladles of various capacities is shown. In particular, it was not possible to inject granular magnesium without additives with lances used to inject mixtures of magnesium with fillers into the melt due to blockage of the channel of the magnesium wire at the outlet of the lance. To solve this problem, a lance of a new design was developed, at the outlet of the channel of which an evaporation chamber was installed, the task of which was to remove the section of the lance channel from direct contact with cast iron. The design of tuyeres with evaporation chambers made it possible to virtually eliminate blockages of the tuyere channel. The studies of the interaction of magnesium with molten iron became the scientific basis for the creation of a modern highly automated process for the secondary refining of cast iron by mono-injection of magnesium without additives. This technology received the most successful application in the creation of modernized complexes at Chinese enterprises. Since 2001, 84 complexes of out-of-furnace desulphurization of pig iron and slag download using ISI technology with a total capacity of over 100 million tons/year of low-sulfur and pig iron-free slag have been built and commissioned at 39 plants in China.

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Kübler, Jakob, R. Baechtold, Gurdial Blugan, K. Lemster, and S. Fuso. "Failure Analysis on a De-NOx Catalyst of a Large Waste Burner." Key Engineering Materials 290 (July 2005): 78–85. http://dx.doi.org/10.4028/www.scientific.net/kem.290.78.

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Modern waste burners are equipped with catalysts to reduce NOX. During operation the catalysts and their performance are influenced by, for example rapid temperature changes, facility vibrations, cleaning procedures and unwashed exhaust gas (when the catalyst is installed before the washer). The catalyst discussed in this paper comprised over 2’500 extruded elements of 150 x 150 x 770 mm3. During commissioning the catalyst elements exhibited a tendency to spall off pieces, thus preventing acceptance of the plant. For the failure analysis, one element from the catalyst was removed and two spare elements were selected. The investigation comprised a visual check, fractography, measurement of the most important physical, mechanical and chemical properties, and a microstructural analysis. It could be shown that: − Processing defects, such as extrusion defects, were the source of cracks which led to pieces spalling off; − Hot steam, used for periodic cleaning, reduced the structural strength by half; − The elements were exposed to higher mechanical loads than expected during transport; − The cleaning process, in combination with particles transported by the exhaust gas, has an erosive effect on the catalyst material; − Blockages, caused by catalyst material among other things, could be found at different depths; − The chemical composition did not significantly differ between used and unused elements. In summary, the failure analysis led to an understanding of the failure mechanism and to a set of recommendations for improvements whose implementation ultimately led to the plant being cleared for operation.

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Kupriyanov, V. V., I. O. Temkin, and I. S. Bondarenko. "Study of the Time Characteristics for Emergency Situations in the Coal Mines." Occupational Safety in Industry, no. 1 (January 2022): 39–45. http://dx.doi.org/10.24000/0409-2961-2022-1-39-45.

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The problems directly related to ensuring safety of work in the coal mines are considered. Statistical, technical, and expert analyses was carried out using available research data on the causes and conditions of various underground accidents (methane and coal dust explosions, blockages and collapses, endogenous fires, etc.) at the coal mines in Russia and other coal-producing countries over the past 15 years. The results of studies of natural, technical, and organizational factors of accidents showed that there is a tendency to preserving their number. Possible reasons for a rather high accident rate in the mines, including fatal injuries to personnel, are as follows: insufficient time reserve to escape from the accidents, which, moreover, is not used to the full extent by the mine personnel and management dealing with safety issues during accidents; decisions on establishing the nature and causes of accidents are made on the basis of unreliable information; the development of accidents is influenced by the uncontrollable and beyond control factors. Temporary model of the accident development is proposed. In six different accidents, the structural pattern is established, which is expressed as a golden wurf. This fact shows that there is an optimal dependence between the available time margin and the time to recover from an accident of any complexity. Natural, technical, and organizational factors influencing the margin of time for recovery from the accidents are considered. The importance is shown concerning careful filtration of the digital and voice messages content for the mine personnel when analyzing accidents. The concept of filtration procedure is formulated.

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Dzyuba, L., Kh Lishchynska, and A. Somyk. "VALUATION OF DURABILITY OF ROD PILLARS OF THE SLOPY RESCUING DEVICE." Bulletin of Lviv State University of Life Safety 21 (July 30, 2020): 67–72. http://dx.doi.org/10.32447/20784643.21.2020.07.

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The need for special saving devices arises during emergency response. Such situations are connected with rescuing of people or animals from deep narrow holes or even from under blockages of constructions. By using the saving devices the cargo raising on a certain height is possible if other ways of delivery are absent. Main structural elements of saving devices are three rod pillars. Top ends of rods are connected in a mounting knot. Often the saving device is equipped with the winch. The winch could be fasten to one of the rod pillars or have individual placing. Rescuing devices differ in a type of a rod design (straight or a slopy plane), loading capacity, rods production material, type of rods connection, a possibility of using on slopes with pillars location in the different planes, modifications of winches, compactness during transportation. There is a big variety of rescuing devices, however in the market of Ukraine offer mostly straight rod rescuing devices. Therefore there is a need for creation of design and durability checking of the slopy rod rescuing device which could be applied to carrying out rescue operations from bridges, buildings and other constructions. In this work it is performed an estimation of durability of a design of the slopy rod rescuing device. It is considered three cases of the support pillars placement. The first case is when pillars of the slopy rescuing device are placed in one horizontal plane. The second case - the longest rod pillar is placed on a ledge. The third case - two shorter rod pillars are placed on a ledge. For each of these cases it is established a type of deformation of rods of the saving device. Construction rods are stretching or compression during work are and loaded with longitudinal forces. From the stretching durability condition the cross section of steel rods is picked up.

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Sudhakar, B. G. K. "Structural heart disease interventions." Clinical Research and Clinical Trials 3, no. 5 (June 25, 2021): 01–05. http://dx.doi.org/10.31579/2693-4779/042.

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Seed for invasive cardiology was sown in early part of nineties. Cardiac catheterization was actually pioneered by Werner Forssmann in 1929. However, credit for therapeutic interventional cardiology should go to US vascular radiologist, Charles Theodore Dotter for performing first peripheral arterial angioplasty [PTA] in 1964. Subsequently, a German cardiologist by name Andreas Gruentzig adapted the technique in 1974 to suit coronary artery disease and performed the first human coronary balloon angioplasty to treat blockage in coronary artery in 1977.

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Glittová, Klaudia, and Miroslav Šipikal. "University Science Parks as an Innovative Tool for University-Business Cooperation." European Conference on Innovation and Entrepreneurship 17, no. 1 (September 7, 2022): 648–56. http://dx.doi.org/10.34190/ecie.17.1.399.

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Collaboration between universities, business and government is important in creating innovation, but often they face barriers which block the successful cooperation among institutional spheres. To improve and strengthen collaboration and overcome existing barriers were created hybrid organizations (like university science parks, research centres or incubators) to address innovation blockages. With the growing popularity of this tool among regional policy makers, there is a need to specify their roles and functions in regional innovation systems. The main goal of our paper is to examine the contribution of university science parks and research centres in Slovakia, which were built thanks to financial support from European Structural and Investment Funds (ESIF). University science parks (USPs) and research centres (RCs) are tools for connecting the university, industry and government sector in a Triple helix framework. They create a suitable space for generating innovation with existing resources at universities, research institutes, research departments of companies and governments, and improve them through mutual interactions. We applied the method of quantitative research – an online questionnaire survey complemented with interviews, which we used to collect basic data on all science parks in Slovakia. The key question in the article is whether research infrastructures represent effective investment with long-term sustainability. We evaluated the current functioning of the parks in terms of fulfilling the functions that contribute to innovation creation, because quality and modern infrastructure is a prerequisite for the implementation of research, the results of which have a high development and innovation potential. We found that the research infrastructure doesn’t perform the required functions, which were declared during their creation. The main barriers to development include insufficient funding for research, technological infrastructure and long-term financing of professional staff. Unclear conditions for the continued operation of parks and uncertain position of government support shows that these investment projects financed by the European Funds are not independently viable after the end of the sustainability period.

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Bordoni, Massimiliano, M. Giuseppina Persichillo, Claudia Meisina, Stefano Crema, Marco Cavalli, Carlotta Bartelletti, Yuri Galanti, Michele Barsanti, Roberto Giannecchini, and Giacomo D'Amato Avanzi. "Estimation of the susceptibility of a road network to shallow landslides with the integration of the sediment connectivity." Natural Hazards and Earth System Sciences 18, no. 6 (June 22, 2018): 1735–58. http://dx.doi.org/10.5194/nhess-18-1735-2018.

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Abstract. Landslides cause severe damage to the road network of the hit zone, in terms of both direct (partial or complete destruction of a road or blockages) and indirect (traffic restriction or the cut-off of a certain area) costs. Thus, the identification of the parts of the road network that are more susceptible to landslides is fundamental to reduce the risk to the population potentially exposed and the financial expense caused by the damage. For these reasons, this paper aimed to develop and test a data-driven model for the identification of road sectors that are susceptible to being hit by shallow landslides triggered in slopes upstream from the infrastructure. This model was based on the Generalized Additive Method, where the function relating predictors and response variable is an empirically fitted smooth function that allows fitting the data in the more likely functional form, considering also non-linear relations. This work also analyzed the importance, on the estimation of the susceptibility, of considering or not the sediment connectivity, which influences the path and the travel distance of the materials mobilized by a slope failure until hitting a potential barrier such as a road. The study was carried out in a catchment of northeastern Oltrepò Pavese (northern Italy), where several shallow landslides affected roads in the last 8 years. The most significant explanatory variables were selected by a random partition of the available dataset in two parts (training and test subsets), 100 times according to a bootstrap procedure. These variables (selected 80 times by the bootstrap procedure) were used to build the final susceptibility model, the accuracy of which was estimated through a 100-fold repetition of the holdout method for regression, based on the training and test sets created through the 100 bootstrap model selection. The presented methodology allows the identification, in a robust and reliable way, of the most susceptible road sectors that could be hit by sediments delivered by landslides. The best predictive capability was obtained using a model in which the index of connectivity was also calculated according to a linear relationship, was considered. Most susceptible road traits resulted to be located below steep slopes with a limited height (lower than 50 m), where sediment connectivity is high. Different land use scenarios were considered in order to estimate possible changes in road susceptibility. Land use classes of the study area were characterized by similar connectivity features. As a consequence, variations on the susceptibility of the road network according to different scenarios of distribution of land cover were limited. The results of this research demonstrate the ability of the developed methodology in the assessment of susceptible roads. This could give the managers of infrastructure information about the criticality of the different road traits, thereby allowing attention and economic budgets to be shifted towards the most critical assets, where structural and non-structural mitigation measures could be implemented.

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Chakrabarti, Nilmadhab, Benoît Roux, and Régis Pomès. "Structural Determinants of Proton Blockage in Aquaporins." Journal of Molecular Biology 343, no. 2 (October 2004): 493–510. http://dx.doi.org/10.1016/j.jmb.2004.08.036.

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Aronov, Alex. "Ligand Structural Aspects of hERG Channel Blockade." Current Topics in Medicinal Chemistry 8, no. 13 (September 1, 2008): 1113–27. http://dx.doi.org/10.2174/156802608785700061.

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Latha Jeevigunta, Naveena Lavanya, E. Susithra, Gouthami Thumma, MV Basaveswara Rao, and Kiran Gangarapu. "A comprehensive review of peptide toxins vs synthetic modulators of BK channels in Epilepsy." Obstetrics Gynecology and Reproductive Sciences 5, no. 05 (August 9, 2021): 01–07. http://dx.doi.org/10.31579/2578-8965/082.

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BK channels, or voltage-gated Ca2+ channels, are essential regulators of neuronal excitability and muscular contractions, all of which are abnormal in epilepsy, a chronic neuronal disease. The form, frequency, and transmission of action potentials (APs), as well as neurotransmitter release from presynaptic terminals, are all influenced by BK channels found in the plasma membrane of neurons. Over the last two decades, several naturally occurring BK channel modulators have attracted a lot of attention. The structural and pharmacological properties of BK channel blockers are discussed in this article. The properties of various venom peptide toxins from scorpions and snakes are first identified, with a focus on their distinctive structural motifs, such as their disulfide bond formation pattern, the binding interface between the toxin and the BK channel, and the functional consequences of the toxins' blockage of BK channels. Then, several non-peptide BK channel blockers are discussed, along with their molecular formula and pharmacological impact on BK channels. The precise categorization and explanations of these BK channel blockers are hoped to provide mechanistic insights into BK channel blockade. The structures of peptide toxins and non-peptide compounds may serve as models for the development of new channel blockers, as well as aid in the optimization of lead compounds for use in neurological disorders.

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Lv, Jianbing, Weijun Wu, Xiaoyu Kang, Juan Huang, Gongfa Chen, Shuai Teng, and Hejie Gao. "Automatic Classification System of Drainage Hole Blockage Based on Convolution Neural Network Transfer Learning." Advances in Civil Engineering 2022 (July 15, 2022): 1–16. http://dx.doi.org/10.1155/2022/4928018.

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The blockage or failure of the drainage holes will endanger the stability of the slopes and traffic safety of a highway tunnel. This paper studies an algorithm for the automatic classification of drainage hole blockage degree based on convolutional neural network transfer learning to explore the intelligent detection method of drainage hole blockage. The model transfer method is adopted to input drainage hole image samples to retrain the pretrained network to classify new images. Experiments are performed on the collected samples of drainage hole images, and the accuracy of different network models is compared, ResNet-18 being the best. The ResNet-18 performance is compared using different transfer strategies and parameters. The results show that when the SGDM gradient optimisation algorithm is used and the learning rate is 0.0001, the identification effect of these samples is the best. The validation accuracy can reach 91.7%, test accuracy is 90.0%, and the effective classification of drainage hole blockage to different degrees is realised under the transfer learning strategy of ResNet-18 model 1–34 frozen layers. Furthermore, with an expansion of the samples in the future, the identification accuracy will be further improved. The automatic classification system of the blockage degree of drainage hole greatly reduces the cost of manual detection, plays a guiding role in the maintenance of drainage pipes, and effectively improves the safety of highway tunnels and slopes.

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DeSilva, Dhammika, David Marlow, David Beale, and Donovan Marney. "Sewer Blockage Management: Australian Perspective." Journal of Pipeline Systems Engineering and Practice 2, no. 4 (November 2011): 139–45. http://dx.doi.org/10.1061/(asce)ps.1949-1204.0000084.

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Chakrabarti, Nilmadhab, Emad Tajkhorshid, Benoı̂t Roux, and Régis Pomès. "Molecular Basis of Proton Blockage in Aquaporins." Structure 12, no. 1 (March 2004): 65–74. http://dx.doi.org/10.1016/j.str.2003.11.017.

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Bröring, Martin. "Coordination polymers built from metal tripyrrin units." Journal of Porphyrins and Phthalocyanines 12, no. 12 (December 2008): 1242–49. http://dx.doi.org/10.1142/s1088424608000625.

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This account summarizes recent advances in the coordination chemistry of tripyrrins and related ligands with a special emphasis on the structural chemistry of coordination polymers with such ligands. The tripyrrin ligand is unique in supporting the formation of 1D- and 3D-supramolecular structures from pentacoordinate transition metal ions due to an effective blockage of their sixth coordination site. Linear coordination polymers have been observed with a multitude of bidentate and tridentate bridging ligands like trifluoroacetate, azide, thio- and selenocyanate, and higher order pseudohalides. Homo- and heterodimetallic species have been obtained by the use of cyanometallates and could be characterized structurally in two cases. Besides the covalent coordination bonds, several secondary interactions like hydrogen bonding and π-stacking were found to support these coordination polymers and are demonstrated to allow the preparation of species with functionalized inner surfaces.

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Kubo, Y., M. Miyazaki, and K. Kato. "Effects of end plates and blockage of structural members on drag forces." Journal of Wind Engineering and Industrial Aerodynamics 32, no. 3 (October 1989): 329–42. http://dx.doi.org/10.1016/0167-6105(89)90006-8.

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Wang, Jingui, Feiyun Luo, Jin Guo, and Su Zhang. "Structural response for vented methane–air deflagrations: Effects of volumetric blockage ratio." Journal of Loss Prevention in the Process Industries 66 (July 2020): 104172. http://dx.doi.org/10.1016/j.jlp.2020.104172.

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Gusev, Evgenii, Alexey Sarapultsev, Liliya Solomatina, and Valeriy Chereshnev. "SARS-CoV-2-Specific Immune Response and the Pathogenesis of COVID-19." International Journal of Molecular Sciences 23, no. 3 (February 2, 2022): 1716. http://dx.doi.org/10.3390/ijms23031716.

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The review aims to consolidate research findings on the molecular mechanisms and virulence and pathogenicity characteristics of coronavirus disease (COVID-19) causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and their relevance to four typical stages in the development of acute viral infection. These four stages are invasion; primary blockade of antiviral innate immunity; engagement of the virus’s protection mechanisms against the factors of adaptive immunity; and acute, long-term complications of COVID-19. The invasion stage entails the recognition of the spike protein (S) of SARS-CoV-2 target cell receptors, namely, the main receptor (angiotensin-converting enzyme 2, ACE2), its coreceptors, and potential alternative receptors. The presence of a diverse repertoire of receptors allows SARS-CoV-2 to infect various types of cells, including those not expressing ACE2. During the second stage, the majority of the polyfunctional structural, non-structural, and extra proteins SARS-CoV-2 synthesizes in infected cells are involved in the primary blockage of antiviral innate immunity. A high degree of redundancy and systemic action characterizing these pathogenic factors allows SARS-CoV-2 to overcome antiviral mechanisms at the initial stages of invasion. The third stage includes passive and active protection of the virus from factors of adaptive immunity, overcoming of the barrier function at the focus of inflammation, and generalization of SARS-CoV-2 in the body. The fourth stage is associated with the deployment of variants of acute and long-term complications of COVID-19. SARS-CoV-2’s ability to induce autoimmune and autoinflammatory pathways of tissue invasion and development of both immunosuppressive and hyperergic mechanisms of systemic inflammation is critical at this stage of infection.

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Journal articles on the topic 'Structural blockages'

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