Academic literature on the topic 'Large Size Tunnel'
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Journal articles on the topic "Large Size Tunnel"
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Gravish, Nick, Mateo Garcia, Nicole Mazouchova, Laura Levy, Paul B. Umbanhowar, Michael A. D. Goodisman, and Daniel I. Goldman. "Effects of worker size on the dynamics of fire ant tunnel construction." Journal of The Royal Society Interface 9, no. 77 (August 22, 2012): 3312–22. http://dx.doi.org/10.1098/rsif.2012.0423.
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Social insects work together to complete tasks. However, different individuals within a colony may vary in task proficiency. We investigated if fire ant ( Solenopsis invicta ) worker body size influenced the ability to construct tunnels—a key component of subterranean nests. We monitored excavation by worker groups in a substrate of small wetted glass particles in quasi-two-dimensional arenas. Morphological and network features of the tunnel system were measured. Total tunnel area did not differ significantly between groups of large and small workers, although the tunnel area of control sized workers was significantly larger than that of large workers. Moreover, large workers created wider but shorter tunnels, with slower growth rate of tunnel number. However, edge–vertex scaling and degree distribution of the tunnel network were similar across all treatments. In all cases, the amount of excavated material was correlated with the number of active workers. Our study reveals that morphological features of excavated tunnels show modest variation when constructed by workers of varying sizes, but topological features associated with the tunnel network are conserved. These results suggest that important behavioural aspects of tunnel construction—and thus nest building—are similar among morphologically distinct members of fire ant societies.
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Liu, Li Yu, Zhi Yi Chen, and Yong Yuan. "Seismic Design and Analysis of Large-Size Shield Tunnels. Part I: Parametric Study." Applied Mechanics and Materials 105-107 (September 2011): 1299–303. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1299.
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According to the extensive application of shield tunnel, large-diameter shield tunnel in particular, structure stiffness of shield tunnels varies in a large rang. In this paper, shield tunnels with different diameters and thicknesses are analyzed and calculated by time-history method. Stiffness ratio is identified to measure the relationship of structure’s stiffness and soil’s stiffness. The results indicate that dynamic moment and shear forces of shield tunnels have positive correlation with the stiffness ratio. Axial forces have positive correlation with thickness and diameter of lining structure.
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Liu, Li Yu, Zhi Yi Chen, and Yong Yuan. "Seismic Design and Analysis of Large-Size Shield Tunnels. Part II: Modified Stiffness Solution." Applied Mechanics and Materials 105-107 (September 2011): 1308–12. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.1308.
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According to the extensive application of shield tunnel, large-diameter shield tunnel in particular, a simplified seismic design method is in urgent need. The equivalent static method is more suitable for the rigid underground structure, rather than flexible structure such as large-diameter shield tunnel. In this paper, shield tunnels with different diameters and thicknesses are analyzed and calculated by time-history method and free field deformation method. The calculation and analysis above help to identify the stiffness ratio to measure the relationship of structure’s stiffness and soil’s stiffness and the derivation of a revised stiffness solution based on the free field deformation method. The results indicate that this method can calculate seismic stress of shield tunnels with different diameters and thicknesses accurately.
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Wu, Lin, Xiedong Zhang, Wei Wang, Xiancong Meng, and Hong Guo. "Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration." Applied Sciences 11, no. 16 (August 18, 2021): 7577. http://dx.doi.org/10.3390/app11167577.
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Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.
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Zhang, Zhien, Mingli Huang, Chunbo Yu, and Xiaojian Fu. "Study on the Face Stability of a Metro Tunnel in a Silty Clay Layer Constructed Using the Full-Face Method." Symmetry 13, no. 6 (June 15, 2021): 1069. http://dx.doi.org/10.3390/sym13061069.
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The horizontal displacement of the soil at the face of the subway tunnel is symmetrically distributed along the central axis of the tunnel, which is larger in the middle and smaller at both sides. The displacement is related to the size of the excavation face. If the excavation area is too great, the horizontal displacement of the tunnel face will be too large, easily leading to tunnel face collapse. For this reason, tunnel builders often use the core-keeping ring-cut method to build subway tunnels. A large section is divided into several small sections to reduce the soil displacement caused by soil excavation. With the continuous promotion and application of mechanized construction in the field of tunnels, mechanized full-section construction will gradually be performed in urban subway tunnels. Once the change in construction method from the core-keeping ring-cut method to the full-face method is made, the issue of how to maintain the stability of the tunnel working face (especially the soft soil stratum) becomes the focus of attention. Taking silty clay as the research object, this paper studies the displacement law of core soil with regard to the tunnel face under the condition of full-face excavation by using theoretical analysis, numerical simulations, and outdoor tests. According to the research results, the extrusion displacement of the tunnel face is the main cause of tunnel displacement. We optimize the construction parameters of glass fiber anchors to strengthen the tunnel face and provide theoretical guidance for the safe construction of subway tunnels.
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Jaecker, Vera, Mirco Herbort, Bertil Bouillon, Daniel Günther, and Sven Shafizadeh. "High incidence of tunnel collision in combined ACL reconstruction and LET." Orthopaedic Journal of Sports Medicine 8, no. 5_suppl4 (May 1, 2020): 2325967120S0031. http://dx.doi.org/10.1177/2325967120s00313.
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Aims and Objectives: Lateral extra-articular tenodesis (LET) procedures are being increasingly performed as concomitant procedures to both primary and revision intra-articular ACL reconstructions with the purpose of controlling excessive anterolateral rotatory instability and to reduce tension on the ACL graft. There is, however, a lack of evidence on benefits and pitfalls of different femoral LET attachment positions. The purpose of this study was to assess the risk of tunnel convergence in combined ACL and LET procedures comparing two different femoral attachment sites (Lemaire and MacIntosh). Materials and Methods: 10 fresh-frozen cadaver knees were examined. In each specimen an anatomic ACL femoral tunnel and two LET tunnels were drilled applying the Lemaire and MacIntosh position. Following knee dissection, minimal distances between ACL and LET tunnels were directly measured on the lateral femoral cortex. Furthermore, computed tomography (CT) scans were obtained to measure inter-tunnel convergence and lateral femoral condyle (LFC) width. Based on the average LFC width, knees were divided into large and small knees to determine a relationship between knee size and tunnel convergence. Results: Convergence of ACL and LET tunnels occurred in 7 of 10 cases (70%) using the Lemaire attachment position. All tunnel collisions occurred directly on the lateral femoral cortex, while inter-tunnel conflicts were not observed. Collisions emerged in both, small (n=4) and large (n=3) knees. Critical tunnel convergence did not occur using the MacIntosh position. The mean minimal distance between the LET and ACL tunnel using the Lemaire and MacIntosh position was 3.1±4.6 mm and 9.8±5.4 mm, respectively. Conclusion: A high risk of tunnel convergence was observed in combined ACL and LET reconstruction using the Lemaire technique, independent of the knee size. LET femoral tunnel positioning according to the MacIntosh reconstruction can significantly reduce the risk of tunnel collision. These findings help to intraoperatively raise the awareness for the risk of tunnel convergence in combined ACL and LET procedures. Adjustments on ACL reconstruction techniques and especially on the femoral fixation have to be considered when applying an additional Lemaire reconstruction.
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Jaecker, Vera, Philip Ibe, Christoph H. Endler, Thomas R. Pfeiffer, Mirco Herbort, and Sven Shafizadeh. "High Risk of Tunnel Convergence in Combined Anterior Cruciate Ligament Reconstruction and Lateral Extra-articular Tenodesis." American Journal of Sports Medicine 47, no. 9 (June 13, 2019): 2110–15. http://dx.doi.org/10.1177/0363546519854220.
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Background: Lateral extra-articular tenodesis (LET) is being increasingly added to primary and revision anterior cruciate ligament (ACL) reconstruction to address residual anterolateral rotatory instability. However, currently there is a lack of knowledge on how close the femoral tunnels are when combining these procedures. Purpose/Hypotheses: To assess the risk of tunnel convergence in combined ACL and LET procedures using 2 different surgical techniques (Lemaire and MacIntosh). It was hypothesized that the risk of tunnel convergence would be greater when using the more distally located Lemaire position. The authors further hypothesized that tunnel proximity would be influenced by knee size. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen cadaveric knees were used for this study. In each specimen, an anatomic ACL femoral tunnel and 2 LET tunnels were drilled using the Lemaire and MacIntosh positions, respectively. After knee dissection, minimal distances between each ACL and LET tunnel were directly measured on the lateral femoral cortex. Furthermore, computed tomography scans were obtained to measure intertunnel convergence and lateral femoral condyle (LFC) width. On the basis of the average LFC width, knees were divided into large and small knees to determine a relationship between knee size and tunnel convergence. Results: Convergence of ACL and LET tunnels occurred in 7 of 10 cases (70%) using the Lemaire attachment position. All tunnel collisions occurred directly on the lateral femoral cortex, while intertunnel (intramedullary) conflicts were not observed. Collisions emerged in both small (n = 4) and large (n = 3) knees. Critical tunnel convergence did not occur using the MacIntosh position. The mean minimal distance between the LET and ACL tunnel using the Lemaire and MacIntosh positions was 3.1 ± 4.6 mm and 9.8 ± 5.4 mm, respectively. Conclusion: Tunnel convergence was more frequently observed in combined ACL and LET reconstruction using the Lemaire technique, independent of the knee size. LET femoral tunnel positioning according to the MacIntosh reconstruction was not associated with tunnel collision. Clinical Relevance: These findings help to raise the awareness for the risk of tunnel convergence in combined ACL and LET procedures. Surgeons may contemplate adjustments on the ACL femoral tunnel drilling technique or fixation device when applying an additional Lemaire procedure. However, in the absence of clinical outcome studies comparing different LET techniques, it remains unclear which technique is superior in a clinical setting.
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Owandkar, Asha, Jayashree Jogi, Tejas Sangle, Vivekanand Bachche, and Dr A. W. Dhawale. "Flood Control Strategy Chandoli Reservoir Using Tunnel Construction Approach a Case Study of Warna River in Kolhapur." International Journal for Research in Applied Science and Engineering Technology 10, no. 5 (May 31, 2022): 337–40. http://dx.doi.org/10.22214/ijraset.2022.42116.
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Abstract: Floods are the most frequent and damaging of all types of natural disasters and annually affect the lives of millions all over the globe. Against this background, enhanced climate variability and climate change are expected to increase the frequency and intensity of floods. There are growing demands for deep tunnels to mitigate severe rural flooding by providing a large tunnelling capacity for excess storm runoff. This study aims to assess the flooding mitigation effect of a deep tunnel system proposed in the old downtown of Kolhapur, India. By providing a sufficient tunnel of a particular type of size, we can reduce the flood force on the downstream side for minimizing the negative impacts of floods, often making the difference between life and death Keywords: Flood, River, Tunnel, Dam, Diversion, Rainfall
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Peterie, Shelby L., and Richard D. Miller. "Near-surface scattering phenomena and implications for tunnel detection." Interpretation 3, no. 1 (February 1, 2015): SF43—SF54. http://dx.doi.org/10.1190/int-2014-0088.1.
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Tunnel locations are accurately interpreted from diffraction sections of focused mode converted P- to S-wave diffractions from a perpendicular tunnel and P-wave diffractions from a nonperpendicular (oblique) tunnel. Near-surface tunnels are ideal candidates for diffraction imaging due to their small size relative to the seismic wavelength and large acoustic impedance contrast at the tunnel interface. Diffraction imaging algorithms generally assume that the velocities of the primary wave and the diffracted wave are approximately equal, and that the diffraction apex is recorded directly above the scatterpoint. Scattering phenomena from shallow tunnels with kinematic properties that violate these assumptions were observed in one field data set and one synthetic data set. We developed the traveltime equations for mode-converted and oblique diffractions and demonstrated a diffraction imaging algorithm designed for the roll-along style of acquisition. Potential processing and interpretation pitfalls specific to these diffraction types were identified. Based on our observations, recommendations were made to recognize and image mode-converted and oblique diffractions and accurately interpret tunnel depth, horizontal location, and azimuth with respect to the seismic line.
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Zhu, Lin-Lin, Jun-Chao Wu, Yi-Ping Wang, Du He, Wen-Yan Zhang, Tao Gan, and Jin-Lin Yang. "Endoscopic Submucosal Single- or Multi-tunnel Dissection for Near-Circumferential and Circumferential Superficial Esophageal Neoplastic Lesions." Gastroenterology Research and Practice 2019 (March 12, 2019): 1–7. http://dx.doi.org/10.1155/2019/2943232.
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This study reports the outcomes of endoscopic submucosal single-tunnel dissection or endoscopic submucosal multi-tunnel dissection for the treatment of esophageal neoplastic lesions of at least three-quarters of the esophageal circumference, including circumferential superficial esophageal neoplastic lesions. From July 2014 to February 2018, a total of 124 lesions underwent endoscopic submucosal tunnel dissection at our hospital. One to four submucosal tunnels were created in the oral to anal direction. Of the 124 lesions, there were 83 noncomplete circumferential lesions and 41 circumferential lesions. Endoscopic submucosal single-tunnel dissection was performed in 54 patients, two-tunnel dissection in 43 patients, three-tunnel dissection in 19 patients, and four-tunnel dissection in 8 patients. The mean dissection speed was 22.8±12.7 mm2/min. En bloc dissection was achieved in all lesions, and the R0 resection rate was 70.2 percent. No matter how large the lesion area was, there were no significant differences in the dissection speed and the R0 resection rate when lesions were at least three-quarters of the esophageal circumference. Esophageal stricture was observed in 54 patients and was relieved by placement of a retrievable metal stent or by endoscopic water balloon dilation. No recurrence was noted after 19.1±12.4 months of follow-up. Our large sample size study showed that endoscopic submucosal tunnel dissection showed effectiveness and safety for the treatment of large superficial esophageal neoplastic lesions at least three-quarters of the esophageal circumference, including circumferential superficial esophageal neoplastic lesions.
Books on the topic "Large Size Tunnel"
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Syed, Almas, Robert Evans Heithaus, and Chet R. Rees. Elimination of Post-Procedural Bleeding After Placement of Tunneled Dialysis Catheters. Edited by S. Lowell Kahn, Bulent Arslan, and Abdulrahman Masrani. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199986071.003.0047.
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This chapter discusses how to prevent postoperative bleeding with the placement of tunneled dialysis catheters. Tunneled intravenous chest catheters, particularly dialysis catheters, sometimes result in oozing or frank bleeding from the incisions during the first 24 hours after placement. This problem is exacerbated by the large diameter and stiffness of these catheters. Moreover, patients requiring these catheters frequently suffer from abnormal hemostasis profiles—an elevated international normalized ratio, thrombocytopenia, or abnormal platelet function due to uremia is commonly seen. The technique discussed in this chapter ensures that the potential bleeding sites throughout the operative site and tract are coated and permeated by a hemostatic agent.
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Shaibani, Aziz. Pseudoneurologic Syndromes. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190661304.003.0022.
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The term functional has almost replaced psychogenic in the neuromuscular literature for two reasons. It implies a disturbance of function, not structural damage; therefore, it defies laboratory testing such as MRIS, electromyography (EMG), and nerve conduction study (NCS). It is convenient to draw a parallel to the patients between migraine and brain tumors, as both cause headache, but brain MRI is negative in the former without minimizing the suffering of the patient. It is a “software” and not a “hardware” problem. It avoids irritating the patient by misunderstanding the word psychogenic which to many means “madness.”The cause of this functional impairment may fall into one of the following categories:• Conversion reaction: conversion of psychological stress to physical symptoms. This may include paralysis, hemisensory or distal sensory loss, or conversion spasms. It affects younger age groups.• Somatization: chronic multiple physical and cognitive symptoms due to chronic stress. It affects older age groups.• Factions disorder: induced real physical symptoms due to the need to be cared for, such as injecting oneself with insulin to produce hypoglycemia.• Hypochondriasis: overconcern about body functions such as suspicion of ALS due to the presence of rare fasciclutations that are normal during stress and after ingestion of a large amount of coffee. Medical students in particular are targets for this disorder.The following points are to be made on this topic. FNMD should be diagnosed by neuromuscular specialists who are trained to recognize actual syndrome whether typical or atypical. Presentations that fall out of the recognition pattern of a neuromuscular specialist, after the investigations are negative, they should be considered as FNMDs. Sometimes serial examinations are useful to confirm this suspicion. Psychatrists or psychologists are to be consulted to formulate a plan to discover the underlying stress and to treat any associated psychiatric disorder or psychological aberration. Most patients think that they are stressed due to the illness and they fail to connect the neuromuscular manifestations and the underlying stress. They offer shop around due to lack of satisfaction, especially those with somatization disorders. Some patients learn how to imitate certain conditions well, and they can deceive health care professionals. EMG and NCS are invaluable in revealing FNMD. A normal needle EMG of a weak muscles mostly indicates a central etiology (organic or functional). Normal sensory responses of a severely numb limb mean that a lesion is preganglionic (like roots avulsion, CISP, etc.) or the cause is central (a doral column lesion or functional). Management of FNMD is difficult, and many patients end up being chronic cases that wander into clinics and hospitals seeking solutions and exhausting the health care system with unnecessary expenses.It is time for these disorders to be studied in detail and be classified and have criteria set for their diagnosis so that they will not remain diagnosed only by exclusion. This chapter will describe some examples of these disorders. A video clip can tell the story better than many pages of writing. Improvement of digital cameras and electronic media has improved the diagnosis of these conditions, and it is advisable that patients record some of their symptoms when they happen. It is not uncommon for some Neuromuscular disorders (NMDs), such as myasthenia gravis (MG), small fiber neuropathy, and CISP, to be diagnosed as functional due to the lack of solid physical findings during the time of the examination. Therefore, a neuromuscular evaluation is important before these disorders are labeled as such. Some patients have genuine NMDs, but the majority of their symptoms are related to what Joseph Marsden called “sickness behavior.” A patient with carpal tunnel syndrome (CTS) may unconsciously develop numbness of the entire side of the body because he thinks that he may have a stroke.
Book chapters on the topic "Large Size Tunnel"
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Zhao, Quanmin, Dawei Li, Zuowei Liu, and Chaofeng Wang. "Shield Treatment Technology for Large-Size Pebble Stratum." In Key Technologies for Tunnel Construction under Complex Geological and Environmental Conditions, 207–58. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-1383-8_4.
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Ishibashi, K., K. Takeno, K. Mori, T. Sakae, Y. Matsumoto, A. Katase, S. Takada, et al. "Detection of 6 keV X-rays by Using Large-Size Nb-Based Tunnel Junctions." In Advances in Superconductivity II, 1029–32. Tokyo: Springer Japan, 1990. http://dx.doi.org/10.1007/978-4-431-68117-5_223.
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He, Jiangling, Min Liu, Xinghong Jiang, and Langping Xiong. "Research on key construction parameters of double-side heading method for newly-added four-lane tunnel with super large section." In Frontiers in Civil and Hydraulic Engineering, Volume 1, 110–21. London: CRC Press, 2023. http://dx.doi.org/10.1201/9781003344209-15.
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Han, Jun, Guodong Chen, Tao Liu, and Qian Yang. "Research on the Automatic Detection Method of Tunnel Clearance Based on Point Cloud Data." In Advances in Transdisciplinary Engineering. IOS Press, 2020. http://dx.doi.org/10.3233/atde200236.
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Due to the deformation of the tunnel and the abnormal outburst of internal facilities, the existing railway tunnel line needs to be inspected regularly. However, the existing detection methods have some shortcomings, such as large measurement interference, low efficiency, discontinuity of section, and independence with the track structure. Therefore, an automatic detection method of tunnel space clearance based on point cloud data is proposed. By fitting the central axis of the tunnel, the extraction can be realized at any position of the tunnel. The coordinate system of tunnel gauge detection based on rail top surface is established, and different types of tunnel gauge frames are introduced. The improved ray algorithm method is used to realize automatic detection and analysis of various tunnel types. Field experiments on existing railway tunnels show that the method can accurately obtain the limit point and size of the tunnel. The cross-section of transgression is obtained. It can meet the requirements of tunnel detection accuracy and has great practicability in tunnel disease detection.
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Tripathi, Suman Lata. "Low-Power High-Performance Tunnel FET With Analysis for IoT Applications." In Handbook of Research on the Internet of Things Applications in Robotics and Automation, 47–67. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-9574-8.ch002.
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The emerging tunnel FET is analysed in terms of ON-state current, OFF-state current, subthreshold slope, switching capacitance to explore its applications for smaller size low-power high-speed digital and memory applications that are an integral part of portable intelligent devices for IoT applications. A large portion of IoT systems are associated with these embedded SRAM/DRAM memories that contribute to a major portion of power dissipation in systems-on-chip (SoCs) or digital design. Several SRAM cell-based memory designs with TFET structures are compared to focus their applications. The ambilpolar nature of TFET structures are investigated for highly random, unclonable secured hardware systems. New circuit designs with TFET were explored for turn-on voltage reduction, ON-state resistance reduction, and reverse leakage reduction techniques that plays an important role in designing efficient energy-harvesting systems.
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Li, Songhui, Ruiqiang Liu, Shaokong Feng, Huihong Zhong, and Yan Zhang. "Research on Void Defect Distribution Law and Structural Optimization Design of Sandwich-Structured Immersed Tunnel in the Shenzhen-Zhongshan Channel." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220893.
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A sandwich-structured immersed tunnel (SSIT) is composed of a fully enclosed steel shell and internal self-compacting concrete. The SSIT has the advantages of both steel and concrete structures and is the optimal solution for the high water pressure and long span that will characterize the future submarine tunnel projects. However, the immersed tube of the structure cannot be vibrated during casting of the self-compacting concrete, and thus the joint surface between the steel plate and concrete is prone to void defects. This reduces the bearing capacity of the immersed tube structure and affects its overall safety. Based on a large number of defect detection data from the SSIT in the Shenzhen-Zhongshan Channel project, this study analyzed and revealed the distribution law of void defects and the corresponding influencing factors. The results show that (1) the casting quality of self-compacting concrete is significantly affected by high temperature, and the necessary temperature control measures should be taken to reduce the defect rate of immersed tubes during construction in the high temperature season; (2) the size of a single casting compartment should not be excessively large. The statistical results show that the pouring effect is the best when the distance from the casting hole is 1.2–1.4 m; (3) The T-stiffener structure blocks the transverse flow of self-compacting concrete, and the aspect ratio (B/L) of the compartment structure should be controlled within the range of 0.8–0.85; and (4) the void defects tend to occur near the pouring hole, on both sides of the T-stiffener structure, and at the edge of the bulkhead far from the pouring hole. Therefore, on the premise of meeting the force requirements, the layout of the T-stiffener structures should be reduced and exhaust holes should be increased to reduce the probability of defects.
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Khaneja, Navin. "SQUID Magnetometers, Josephson Junctions, Confinement and BCS Theory of Superconductivity." In Magnetometers - Fundamentals and Applications of Magnetism. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.83714.
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A superconducting quantum interference device (SQUID) is the most sensitive magnetic flux sensor currently known. The SQUID can be seen as a flux to voltage converter, and it can generally be used to sense any quantity that can be transduced into a magnetic flux, such as electrical current, voltage, position, etc. The extreme sensitivity of the SQUID is utilized in many different fields of applications, including biomagnetism, materials science, metrology, astronomy and geophysics. The heart of a squid magnetometer is a tunnel junction between two superconductors called a Josephson junction. Understanding the work of these devices rests fundamentally on the BCS theory of superconductivity. In this chapter, we introduce the notion of local potential and confinement in superconductivity. We show how BCS ground state is formed from interaction of wave packets confined to these local potential wells. The starting point of the BCS theory of superconductivity is a phonon-mediated second-order term that describes scattering of electron pair at Fermi surface with momentum k i , − k i and energy 2 ℏ ω i to k j , − k j with energy 2 ℏ ω j . The transition amplitude is M = − d 2 ω d ω i − ω j 2 − ω d 2 , where d is the phonon scattering rate and ω d is the Debye frequency. However, in the presence of offset ω i − ω j , there is also a present transition between states k i , − k i and k j , − k i of sizable amplitude much larger than M . How are we justified in neglecting this term and only retaining M ? In this chapter, we show all this is justified if we consider phonon-mediated transition between wave packets of finite width instead of electron waves. These wave packets are in their local potentials and interact with other wave packets in the same well to form a local BCS state we also call BCS molecule. Finally, we apply the formalism of superconductivity in finite size wave packets to high Tc in cuprates. The copper electrons in narrow d-band live as packets to minimize the repulsion energy. The phonon-mediated coupling between wave packets (of width Debye energy) is proportional to the number of k-states in a packet, which becomes large in narrow d-band (10 times s-band); hence, d-wave Tc is larger (10 times s-wave). At increased doping, packet size increases beyond the Debye energy, and phonon-mediated coupling develops a repulsive part, destroying superconductivity at large doping levels.
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Duan, Y. H., H. M. Yang, J. P. Yuan, L. Su, and W. T. Li. "Estimation of Internal Maximum Thermal Stress of Tunnel Side Wall Lining Concrete During Construction Period." In Advances in Transdisciplinary Engineering. IOS Press, 2021. http://dx.doi.org/10.3233/atde210197.
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Thermal cracks in lining concrete of large section hydraulic tunnel usually occur in side walls during construction, and most of them are harmful penetrating cracks. In order to meet the needs of real-time rapid control for engineering design in construction period, nine influencing factors of maximum tensile of side wall lining concrete σmax during construction period are determined on the basis of comprehensive analysis of temperature stress effects and finite element simulations, and their influencing regularities are analyzed. Then the estimation formula of σmax and real-time control method of thermal crack are put forward. Through the application of real-time temperature control and crack prevention control of lining concrete in flood discharge tunnel, the estimation formula of σmax and the real-time thermal crack control method are proved to be correct and applicable.
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Ye, L., D. J. Wang, K. W. He, G. W. Gu, C. Ye, and J. Wang. "Site assembly technologies of super-large slurry TBM." In Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 3441–49. CRC Press, 2020. http://dx.doi.org/10.4324/9781003031635-94.
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Ye, L., D. J. Wang, K. W. He, G. W. Gu, C. Ye, and J. Wang. "Site assembly technologies of super-large slurry TBM." In Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 3441–49. CRC Press, 2019. http://dx.doi.org/10.1201/9780429424441-364.
Full textConference papers on the topic "Large Size Tunnel"
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Parwani, Kamakshi, Jos Bienefelt, Tomas Rakovec, and Frank Haring. "Fire behaviour of large scale loaded tunnel segment tests for project Rotterdamsebaan, The Netherlands." In IABSE Congress, Ghent 2021: Structural Engineering for Future Societal Needs. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2021. http://dx.doi.org/10.2749/ghent.2021.1357.
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<p>Assessing the performance of tunnels in fire is becoming increasingly crucial for the overall usability and durability of the structure. One of the most reliable methods for evaluating the presentation of the concrete during fire in tunnels is by testing. In this work, the fire tests performed on the Victory Boogie Woogietunnel, project Rotterdamsebaan (The Hague, the Netherlands) are discussed. The study aims to assess the fire performance of the cut and cover concrete section when subjected to a tunnel fire curve. A series of 6 fire tests were performed on concrete slabs of the size 5,0 m x 2,4 m x 0,4 m when exposed to Rijkswaterstaat (RWS) fire curve for 120 minutes. Based on the work, one of the main conclusions drawn were that it is necessary to test a large-scale specimen to judge the performance of a protection system accurately. Another important conclusion is that the test specimen should have the concrete mixture which accurately represents the tunnel concrete to avoid uncertainty in the fire induced spalling behaviour of concrete.</p>
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Monti, Rodolfo, Raffaele Savino, Federico De Filippis, Antonio Del Vecchio, and Adolfo Martucci. "Large Size Water Calorimetric Probe for Heat Flux Measurements in the Plasma Wind Tunnel Facilities." In 14th AIAA/AHI Space Planes and Hypersonic Systems and Technologies Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.2006-8048.
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Luo, Junhua, Li Zhang, and Yigang Liu. "Study on the thermal expansion of EHV cable line with large size conductor in tunnel." In IEEE PES T&D 2010. IEEE, 2010. http://dx.doi.org/10.1109/tdc.2010.5484463.
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Etter, R. J., and M. B. Wilson. "The Large Cavitation Channel." In SNAME 23rd American Towing Tank Conference. SNAME, 1992. http://dx.doi.org/10.5957/attc-1992-024.
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The Large Cavitation Channel (LCC) of the David Taylor Model Basin, CDNSWC, is a large variable pressure water tunnel recently put into operation in Memphis, Tennessee. This facility incorporates many of the latest technological concepts in the design of hydrodynamic and hydroacoustic test facilities. This paper discusses a number of the key technical and design issues that had to be addressed first in the basic specifications and then in the final features as constructed. Issues include: size, shape, speed. pressure range, turbulence management, turning vanes, contraction and diffuser, main pump impeller, hydroacoustic considerations of noise sources, quieting, and noise measurement; and operational features involving model size, powering, and measurement of model propulsor thrust and torque.
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YANG, XU, QIAO WEIDONG, and LI HUI. "INSTANCE-SEGMENTATION-BASED DENSE ON-SITE ROCK FRAGMENT RECOGNITION DURING REAL-WORLD TUNNEL EXCAVATION." In Structural Health Monitoring 2021. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/shm2021/36320.
Full textAbstract:
Timely recognition of rock fragments and their morphological sizes can help adjust excavation parameters during tunnel boring machine (TBM) tunneling. Traditional manual inspection highly relies on experiences and subjective judgments of human operators and conducting sieving tests is not real-time and energy-consuming. Rock fragments in real-world images are often observed against a dark background, distributed with high size diversity, complicatedly distributed, and blocked by each other. To solve these problems, this study proposes a novel instance segmentation-based method for on-site rock fragments recognition. The proposed instance segmentation model includes two subnetworks: object detection and semantic segmentation. The results show that 88% of rock fragments can be recognized, and the average recall and average IoU values reach 0.85 and 0.75 on the 15 test images, respectively. Besides, both small and large rock fragments can be recognized well. The predicted size distributions of the major and minor axis lengths of the rock fragments fit well with the ground-truth ones statistically. In conclusion, this study can provide both visual recognition and statistical results for the size distribution of on-site rock fragments.
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Etter, Robert J. "State of the Art - Cavitation Test Facilities and Experimental Methods." In SNAME 26th American Towing Tank Conference. SNAME, 2001. http://dx.doi.org/10.5957/attc-2001-016.
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Cavitation tunnels have played a critical role in the development of ships and other naval vehicles and the associated research applicable to the engineering of these vehicles. Particularly important has been the use of cavitation tunnels in the development of propulsion systems. The paper reviews some aspects of the historical development of the modern cavitation tunnel. It includes aspects of tunnel design such as size, speed, pressure range, acoustics, and materials. Model construction, installation, and instrumentation are discussed. Initially, the most innovative development occurred in 1895 with the invention of the cavitation tunnel by Sir Charles Parsons. More than 100 years later, the cavitation tunnel is still the key test facility used for cavitation research, test and evaluation. Technologies currently used for performance evaluation have changed greatly over those used only a decade or two ago. This has been in part due to incredible innovations in the area of instrumentation and digital electronics as well as the need to characterize modern propulsors in ways not previously required. The evolution of cavitation tunnel capabilities and the use of the tunnel in a large marine research, development, and design organization is largely reviewed by considering the various cavitation tunnels which have been constructed and utilized at the David Taylor Model Basin over several decades.
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Ryan, Sydney D., Andrew G. Gerber, Gorden A. L. Holloway, and Ali Bagherpour. "Computational Study of Aerial Sprays Used for Forest Protection." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30270.
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The efficacy of pesticide sprays is strongly dependent on the accuracy of the droplet size spectrum. Over estimates of droplet size may result in excessive drift or ineffective doses, while under estimates of droplet size result in excessive releases. This situation is not only bad for the environment; it incurs large operating costs (spray usually accounts for 30% of total cost). This paper describes the study of droplet sprays commonly used in the agriculture and forestry management. It combines experimental wind tunnel testing and Computational Fluid Dynamic (CFD) methods to develop a fundamental understanding of droplet generation and dispersion in the wake of the atomizer spray system. The results will assist designers of spray technology and applicators in delivering pesticide to its target. The CFD models that are developed and calibrated will further allow the wind tunnel data to be generalized; thus, allowing less wind tunnel testing and eventually direct simulation of droplet dispersion in aircraft wakes. The CFD models are developed for the poly-dispersed sprays released from a Micronair AU4000 atomizer (a standard atomizer used for forest protection) at an airspeed of 67 m/s. Simulations are performed using a Lagrangian (droplet phase) - Eulerian (fluid phase) procedure and include droplet drag/body forces and turbulent dispersion of droplets. The Base-line Reynolds Stress Model (BSL RSM) turbulence model is used to compute turbulence levels in the air phase. The CFD simulations include the sprayer and a large portion of the wind tunnel geometry in order to facilitate in validation. The computational results are compared to full scale experimental measurements of pressure, gas phase velocity, droplet velocity, and droplet size spectra measured using Phase Doppler Interferometry (PDI) and Hotwire Anemometry. Measurements are available along radial lines at 0.5, 1, 2 and 4 m downstream of the atomizer.
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Abdi, Iman Ashtiani, Morteza Khashehchi, and Kamel Hooman. "Investigation of Large-Scale Structures Behind a Single Tube (Finned and Foamed Tube) Using Two-Point Correlations." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21236.
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Flow structures downstream of a finned-tube are compared to those of an identical pipe; with the same diameter and length, covered with a foam layer. The standard case of cross-flow over a bare tube, i.e. no surface extension, is also tested as a benchmark. Experiments are conducted in a wind tunnel at Reynolds numbers of 4000 and 16000. Particle image velocimetry (PIV) was used for flow visualization on two different perpendicular planes. To characterize the size of the flow structures downstream of the tube, for each of the aforementioned case, two-point correlation, as a statistical analysis tool, has been used. It has been observed that by decreasing the Reynolds number, the flow structures are further stretched in streamwise direction for both bare and finned-tube cases. This is, however, more pronounced with the former. Interestingly, with a foam-wrapped tube the sizes of the flow structures are found to be independent of the Reynolds number. Finally, the structure sizes are smaller in the case of the foam-wrapped tube compared to those of finned-tube.
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Plourde, B. D., J. P. Abraham, G. S. Mowry, and W. J. Minkowycz. "Wind-Tunnel Tests of Vertical-Axis Wind Turbine Blades." In ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/es2011-54604.
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An ongoing research project is investigating the potential of locating vertical-axis wind turbines (WT) on remote, off-grid cellular communication towers. The goal of the WT is to provide local power generation to meet the electrical needs of the tower. While vertical-axis devices are less efficient than their more traditional horizontal-axis counterparts, they provide a number of practical advantages which make them a suitable choice for the present situation. First, the direction of their axis is aligned with the existing tower and its rotation does not interfere with the tower structure. Second, vertical-axis devices are much less susceptible to the direction of wind and they do not require control-systems to ensure they are oriented correctly. Third, vertical-axis turbines have very low start-up wind speeds so that they generate power over a wide range of speeds. Fourth, since vertical-axis turbines rotate at a slower speed compared with horizontal counterparts, they impart a lessened vibration load to the tower. These facts, collectively, make the vertical-axis turbine suitable for the proposed application. The design process involved a detailed initial design of the turbine blade using computational methods. Next, a trio of designs was evaluated experimentally in a large, low-speed wind tunnel. The wind tunnel is operated by the University of Minnesota’s St. Anthony Falls Fluid Laboratory. The tunnel possesses two testing sections. The larger section was sufficient to test a full-size turbine blade. Accounting was taken of the blockage effect following the tests. The experiments were completed on (1) a solid-wing design (unvented), (2) a slotted-wing design (vented), and (3) a capped-and-slotted design (capped). Conditions spanned a wide range of wind speeds (4.5–11.5 m/s). The turbines were connected to electronics which simulated a range of electrical loads. The tested range was selected to span the expected range of resistances which will be found in practice. It was discovered that over a range of these wind speeds and electrical resistances, slots located on the wings result in a slight improvement in power generation. On the other hand, the slotted-and-capped design provided very large increases in performance (approximately 200–300% compared with the unvented version). This large improvement has justified commercialization of the product for use in powering remote, off-grid cellular communication towers.
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Sato, Ryuichi, Takayuki Mori, Ryo Yakushiji, Kenji Naganuma, Masaharu Nishimura, Keizo Nakagawa, and Takao Sasajima. "Conceptual Design of the Flow Noise Simulator." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45303.
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The Flow Noise Simulator (FNS) of the 1st Research Center of TRDI/JDA (Japan Defense Agency) is a large, variable pressure, recirculating water tunnel with very low background noise level. The tunnel is 20m high and 49m long, containing 2000m3 of water. The test section has a square cross section of 2m × 2m with 10m in length. It will accept large size surface ship models of 6m, submarine models of 4m in length and full scale ship appendix models. The FNS is currently under construction and will be accomplished in 2005. It will be used for a wide variety of hydrodynamic and hydroacoustic testing of surface ships and submarines, such as propeller cavitation noise measurements and propeller-hull interaction observation, with sufficiently large scale models. Conceptual design of the FNS was started in 1996 and evaluated by following scale model studies. This paper discusses some technical issues of the FNS.
Reports on the topic "Large Size Tunnel"
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King, E. L., A. Normandeau, T. Carson, P. Fraser, C. Staniforth, A. Limoges, B. MacDonald, F. J. Murrillo-Perez, and N. Van Nieuwenhove. Pockmarks, a paleo fluid efflux event, glacial meltwater channels, sponge colonies, and trawling impacts in Emerald Basin, Scotian Shelf: autonomous underwater vehicle surveys, William Kennedy 2022011 cruise report. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331174.
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A short but productive cruise aboard RV William Kennedy tested various new field equipment near Halifax (port of departure and return) but also in areas that could also benefit science understanding. The GSC-A Gavia Autonomous Underwater Vehicle equipped with bathymetric, sidescan and sub-bottom profiler was successfully deployed for the first time on Scotian Shelf science targets. It surveyed three small areas: two across known benthic sponge, Vazella (Russian Hat) within a DFO-directed trawling closure area on the SE flank of Sambro Bank, bordering Emerald Basin, and one across known pockmarks, eroded cone-shaped depression in soft mud due to fluid efflux. The sponge study sites (~ 150 170 m water depth) were known to lie in an area of till (subglacial diamict) exposure at the seabed. The AUV data identified gravel and cobble-rich seabed, registering individual clasts at 35 cm gridded resolution. A subtle variation in seabed texture is recognized in sidescan images, from cobble-rich on ridge crests and flanks, to limited mud-rich sediment in intervening troughs. Correlation between seabed topography and texture with the (previously collected) Vazella distribution along two transects is not straightforward. However there may be a preference for the sponge in the depressions, some of which have a thin but possibly ephemeral sediment cover. Both sponge study sites depict a hereto unknown morphology, carved in glacial deposits, consisting of a series of discontinuous ridges interpreted to be generated by erosion in multiple, continuous, meandering and cross-cutting channels. The morphology is identical to glacial Nye, or mp;lt;"N-mp;lt;"channels, cut by sub-glacial meltwater. However their scale (10 to 100 times mp;lt;"typicalmp;gt;" N-channels) and the unique eroded medium, (till rather than bedrock), presents a rare or unknown size and medium and suggests a continuum in sub-glacial meltwater channels between much larger tunnel valleys, common to the eastward, and the bedrock forms. A comparison is made with coastal Nova Scotia forms in bedrock. The Emerald Basin AUV site, targeting pockmarks was in ~260 to 270 m water depth and imaged eight large and one small pockmark. The main aim was to investigate possible recent or continuous fluid flux activity in light of ocean acidification or greenhouse gas contribution; most accounts to date suggested inactivity. While a lack of common attributes marking activity is confirmed, creep or rotational flank failure is recognized, as is a depletion of buried diffuse methane immediately below the seabed features. Discovery of a second, buried, pockmark horizon, with smaller but more numerous erosive cones and no spatial correlation to the buried diffuse gas or the seabed pockmarks, indicates a paleo-event of fluid or gas efflux; general timing and possible mechanisms are suggested. The basinal survey also registered numerous otter board trawl marks cutting the surficial mud from past fishing activity. The AUV data present a unique dataset for follow-up quantification of the disturbance. Recent realization that this may play a significant role in ocean acidification on a global scale can benefit from such disturbance quantification. The new pole-mounted sub-bottom profiler collected high quality data, enabling correlation of recently recognized till ridges exposed at the seabed as they become buried across the flank and base of the basin. These, along with the Nye channels, will help reconstruct glacial behavior and flow patterns which to date are only vaguely documented. Several cores provide the potential for stratigraphic dating of key horizons and will augment Holocene environmental history investigations by a Dalhousie University student. In summary, several unique features have been identified, providing sufficient field data for further compilation, analysis and follow-up publications.
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Yogev, David, Ricardo Rosenbusch, Sharon Levisohn, and Eitan Rapoport. Molecular Pathogenesis of Mycoplasma bovis and Mycoplasma agalactiae and its Application in Diagnosis and Control. United States Department of Agriculture, April 2000. http://dx.doi.org/10.32747/2000.7573073.bard.
Full textAbstract:
Mycoplasma bovis and M. agalactiae are two phylogenetically related mycoplasmas which cause economically significant diseases in their respective bovine or small ruminant hosts. These organisms cause persistent asymptomatic infections that can result in severe outbreaks upon introduction of carrier animals into susceptible herds. Little is known about the mechanisms underlying mycoplasma-host interaction, variation in virulence, or of the factors enabling avoidance of the host immune system. In recent years it has become apparent that the ability of pathogenic microorganisms to rapidly alter surface antigenic structures and to fine tune their antigenicity, a phenomena called antigenic variation, is one of the most effective strategies used to escape immune destruction and to establish chronic infections. Our discovery of a novel genetic system, mediating antigenic variation in M. bovis (vsp) as well as in M. agalactiae (avg) served as a starting point for our proposal which included the following objectives: (i) Molecular and functional characterization of the variable surface lipoproteins (Vsp) system of M. bovis and comparison with the Vsp-counterpart in M. agalactiae (ii) Determination of the role of Vsp proteins in the survival of M. bovis when confronted by host defense factors, (iii) Assessment of Vsp-based genetic and antigenic typing of M. bovis and M. agalactiae for epidemiology of infection and (iv) Improvement of diagnostic tests for M. bovis and M. agalactiae based on the vsp-and vsp-analogous systems. We have carried out an extensive molecular characterization of the vsp system and unravelled the precise molecular mechanism responsible for the generation of surface antigenic variation in M. bovis. Our data clearly demonstrated that the two pathogenic mycoplasma species possess large gene families encoding variable lipoprotein antigens that apparently play an important role in immune evasion and in pathogen-host interaction during infection. Phase variable production of these antigens was found to be mediated by a novel molecular mechanism utilizing double site-specific DNA inversions via an intermediate vsp configuration. Studies in model systems indicate that phase variation of VspA is relevant in interaction between M. bovis and macrophages or monocytes, a crucial stage in pathogenesis. Using an ELISA test with captured VspA as an antigen, phase variation was shown to occur in vivo and under field conditions. Genomic rearrangements in the avg gene family of M. agalactiae were shown to occur in vivo and may well have a role in evasion of host defences and establishment of chronic infection. An epidemiological study indicated that patterns of vsp-related antigenic variation diverge rapidly in an M. bovis infected herd. Marked divergence was also found with avg-based genomic typing of M. agalactiae in chronically infected sheep. However, avg-genomic fingerprints were found to be relatively homogeneous in different animals during acute stages of an outbreak of Contagious Agalactiae, and differ between unrelated outbreaks. These data support the concept of vsp-based genomic typing but indicate the necessity for further refinement of the methodology. The molecular knowledge on these surface antigens and their encoding genes provides the basis for generating specific recombinant tools and serological methods for serodiagnosis and epidemiological purposes. Utilization of these methods in the field may allow differentiating acutely infected herds from chronic herds and disease-free herds. In addition the highly immunogenic nature of these lipoproteins may facilitate the design of protective vaccine against mycoplasma infections.