Journal articles: 'Telescopic failure'

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Xu, Ge Ning, Guang Heng Gao, and Zeng Cai Guo. "Analysis on Nonlinear Buckling Failure Influence Factors of Telescopic Boom System Based on Arc-Length and FEM Method." Applied Mechanics and Materials 532 (February 2014): 291–96. http://dx.doi.org/10.4028/www.scientific.net/amm.532.291.

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Telescopic jib is the key load-bearing component for both truck crane and all-terrain crane,seriously affect hoisting capacity of crane. Different stress feature or structural feature produce different affects on the hoisting capacity of telescopic jib. In order to study the mechanism and levels of different factors,multiple telescopic jib models with different factors are built based on nonlinear finite element method. Adopting Arc-length method to analysis structural nonlinear deformation in the whole course,the impact degree for hoisting performance of material yield strength, load eccentricity, lap length of telescopic jib and the support position of lifting hydraulic cylinder are acquired respectively. The results shows: A finite element method combined with arc-length method can be used to analysis the buckling problem of nonlinear deformation of telescopic jib. All the above four factors have affect on the hoisting performance of telescopic jib, but the levels are different. By analyzing change law of impact factors, corresponding measure are adopted in practical deign to reduce its impact and to strengthen the capacity of resisting local buckling of the telescopic jib.

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Hadianfard, M. J., and M. A. Hadianfard. "Structural Failure of a Telescopic Shiploader during Installation." Journal of Failure Analysis and Prevention 7, no. 4 (August 7, 2007): 282–91. http://dx.doi.org/10.1007/s11668-007-9049-x.

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Yao, Jia, Xiaoming Qiu, Zhenping Zhou, Yuqin Fu, Fei Xing, and Erfei Zhao. "Buckling failure analysis of all-terrain crane telescopic boom section." Engineering Failure Analysis 57 (November 2015): 105–17. http://dx.doi.org/10.1016/j.engfailanal.2015.07.038.

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Kahan, Michael E., Nathan R. Angerett, and Jill C. Flanagan. "Intraoperative Hardware Failure of the Fassier–Duval Rescue System in a Pediatric Patient with Osteogenesis Imperfecta." Case Reports in Pediatrics 2021 (May 25, 2021): 1–5. http://dx.doi.org/10.1155/2021/9982289.

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The use of telescopic intramedullary rods for the treatment of lower extremity deformity in children with osteogenesis imperfecta has been well described. The reinforcement of these weakened weightbearing bones with intramedullary devices leads to improvements in mobility that progress into adulthood. Although the current telescopic intramedullary rod systems are an upgrade from earlier systems, they are still associated with high rates of reoperation and complication. We describe a unique complication encountered during a revision which involved the male retriever system for the Fassier–Duval rod (FDR) (Pega Medical, Quebec, CA) experienced intraoperatively. To our knowledge, this mechanism of failure has not been previously described in the literature.

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Prakash, Jatin, Sumit Kumar Gupta, and PK Kankar. "An analytical approach to evaluate the maximum load carrying capacity for pin-mounted telescopic hydraulic cylinder." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 19 (April 11, 2020): 3919–34. http://dx.doi.org/10.1177/0954406220916524.

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The hydraulic cylinder is an actuating mechanical maneuver used to transfer the power from one station to another. For industrial purposes, various types of cylinders are employed as per the requirement. Telescopic hydraulic cylinder, also known as the two-stage hydraulic cylinder is one of the widely used hydraulic cylinders in the industry. The closed center length of a telescopic cylinder is 20% to 40% of the open center length depending on the number of stages. The safe operation of such telescopic hydraulic cylinder is highly essential. One of the prominent failures includes the buckling failure of the hydraulic cylinder. Once the system fails, the operating parameters change abruptly and thus the proper working gets affected. In literature, there is no significant standard that governs the buckling load determination of two-stage hydraulic cylinder. Existing technical standard ISO/TS 13725 : 2016 approach is only prescribed for the single-stage cylinder. In this manuscript, the emphasis is kept upon the determination of the buckling load for the two-stage pin-mounted telescopic hydraulic cylinder. The buckling governing equation has been derived to obtain the buckling load using an analytical approach. Additionally, the stress condition of cylinder barrels of different stages has been discussed per thick cylinder theory. The finite element analysis has been performed for various dimensions of the hydraulic cylinder. The results obtained from analytical results show close vicinity with the finite element results.

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Yao, Jia, Fei Xing, Yuqin Fu, Xiaoming Qiu, Zhenping Zhou, and Jianhong Hou. "Failure analysis of torsional buckling of all-terrain crane telescopic boom section." Engineering Failure Analysis 73 (March 2017): 72–84. http://dx.doi.org/10.1016/j.engfailanal.2016.12.006.

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Xu, Ge Ning, and Kai Hao. "Research on Weld Defects Simulation and Performance Assessment of Solid-Web Type Telescopic Jib." Applied Mechanics and Materials 687-691 (November 2014): 236–42. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.236.

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To research the failure mode of solid-web type telescopic jib typical weld, extract and quantify failure characteristics, obtain failure regularity of jib performance and solve the problem that welds do not be established by conventional finite element analysis. The weld strength is replaced by the maximum stress of the corresponding section, which may cause the simulation results low and distortion, and cannot simulate weld defects. A new modeling method is used by this article, which establishes and simplifies the weld physical shape, simulate and analyze weld strength. The Life and Death element technology which is based on the ANSYS software is used to simulate weld defects. The weld strength that is obtained by conventional analysis simulation is 110MPa, after processing, stress of weld model without defects is 395MPa, the theoretical value be calculated is 437MPa, stress of weld model with defect 1, 2, 3 respectively is 586MPa, 402MPa and 475MPa. Through comparing the simulation value and the theoretical value and the comparison between the simulation values, the simplified model that is proved is reasonable, the technical route which is used to simulate weld defect by Life and death element technology is feasible. It can be used to predict failure critical value under typical working condition, assess whether the weld failure. The working condition of jib can be simulated, and the main factors can be retrospect.

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Cox, India, Louay Al Mouazzen, Sabri Bleibleh, Radu Moldovan, Fiona Bintcliffe, C. Edward Bache, and Simon Thomas. "Combined two-centre experience of single-entry telescopic rods identifies characteristic modes of failure." Bone & Joint Journal 102-B, no. 8 (August 2020): 1048–55. http://dx.doi.org/10.1302/0301-620x.102b8.bjj-2020-0131.r1.

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Aims The Fassier Duval (FD) rod is a third-generation telescopic implant for children with osteogenesis imperfecta (OI). Threaded fixation enables proximal insertion without opening the knee or ankle joint. We have reviewed our combined two-centre experience with this implant. Methods In total, 34 children with a mean age of five years (1 to 14) with severe OI have undergone rodding of 72 lower limb long bones (27 tibial, 45 femoral) for recurrent fractures with progressive deformity despite optimized bone health and bisphosphonate therapy. Data were collected prospectively, with 1.5 to 11 years follow-up. Results A total of 24 patients (33%) required exchange of implants (14 femora and ten tibiae) including 11 rods bending with refracture. Four (5%) required reoperation with implant retention. Loss of proximal fixation in the femur and distal fixation in the tibia were common. Four patients developed coxa vara requiring surgical correction. In total, 13 patients experienced further fractures without rod bending; eight required implant revision. There was one deep infection. The five-year survival rate, with rod revision as the endpoint, was 63% (95% confidence interval (CI) 44% to 77%) for femoral rods, with a mean age at implantation of 4.8 years (1.3 to 14.8), and 64% (95% CI 36% to 82%) for tibial rods, with a mean age at implantation of 5.2 years (2.0 to 13.8). Conclusion FD rods are easier to implant but do not improve on the revision rates reported for second generation T-piece rods. Proximal femoral fixation is problematic in younger children with a partially ossified greater trochanter. Distal tibial fixation typically fails after two years. Future generation implants should address proximal femoral and distal tibial fixation to avoid the majority of complications in this series. Cite this article: Bone Joint J 2020;102-B(8):1048–1055.

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Buelvas Castro, Edgardo Manuel, Fabio Andres Bermejo Altamar, and Ricardo Andrés Mendoza Quiroga. "Failure analysis and repair of the telescopic beam belonging to the spreader of a reach stacker for port operations." Scientia et Technica 25, no. 1 (March 30, 2020): 30–36. http://dx.doi.org/10.22517/23447214.23471.

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Reach stackers land equipment operating in ports of the Colombian Caribbean, are subject to several critical working conditions such as; corrosive environment, excess working hours, overload and lack of predictive maintenance. This work focuses on the failure analysis and the elaboration of the welding repair procedure of the telescopic beam belonging to the spreader of a Reach stacker that operates in a Colombian Caribbean seaport. Initially the fault zone was characterized; by mean a metallographic analysis and a hardness profile to identify the type of structural steel of which the beam is composed, obtaining an A514 grade C of 110KSI of tensile strength and 34HRC of hardness. The equipment manufacturer was verified and the established by the laboratory tests was corroborated. After identifying the material, the fracture area was analyzed where patterns of beach markings were found, typical of a fatigue failure which extended from the circumference of separating pins to the surface of the beam. The inclusion of the separators in the initial design generates stress concentrators in the welding of the pins which increases the fatigue zone combined with the excess load with which the equipment works. This fact could be verified with a technical bulletin published by the manufacturer brand "Taylor" where it indicates this type of failure for the telescopic beam of the Reach stackers. Successively, an FCAW type welding repair procedure is developed in accordance with AWS code D1.1, where the electrode to be used, the cords to be applied, the preheating, and the speeds and conditions recommended for filling the materials are selected cracks. Finally it could be concluded that the fault was generated by fatigue and overload in the welding of the telescopic beam separator pins and its repair will be carried out according to a welding procedure of the AWS code D1.1. The analysis of these types of cases will allow the company to take actions to minimize the new occurrence of the failure such as periodic reviews in that area after the work hours recommended by the manufacturer and the awareness of the equipment operators with the handling of loads on the dock.

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Lu, Feng Yi, Wei Zhu, Ge Ning Xu, and Ru Gang Yang. "The Life Evaluation to Determine Remanufacturing Access Period of Telescopic Boom for Mobile Crane." Applied Mechanics and Materials 551 (May 2014): 182–88. http://dx.doi.org/10.4028/www.scientific.net/amm.551.182.

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In order to determine the remanufacturing access period of telescopic boom for mobile crane, it is needed to study one of its main failure forms—fatigue damage to predict remaining fatigue life which is regarded as parameter to remanufacture and foundation to make comprehensive evaluation. First of all, in certain period, the numbers of work cycles corresponding to different lifting loads for different rated lifting capacity of telescopic boom are collected, so that a set of data can be got as learning sample, then editing a neural network program and training it by entering the learning sample obtain the appropriate neural network weights, finally through inputting rated lifting capacity and lifting loads of telescopic boom needed life evaluation to the neural network program, the numbers of work cycles are obtained. Building on the principle of Miner fatigue damage accumulation and combining with the Paris-Eadogan equation, the formula of remaining fatigue life is deduced, and finally the graph of remaining fatigue life corresponding to different initial crack is drew. The results show that the initial crack effect on the remaining fatigue life largely and crack of 0.4mm should be tracked and monitored as a starting point, so remanufacturing the boom at an appropriate time ensures safe and reliable operation of mobile crane.

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White, G. "V-22 Nacelle Conversion Actuator." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 207, no. 1 (January 1993): 61–72. http://dx.doi.org/10.1243/pime_proc_1993_207_247_02.

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A design outline is given of the actuator that rotates the engine and rotor nacelles on the V-22 aircraft. The actuator comprises a two-stage telescopic ballscrew that is driven either hydraulically from one end or electrically from the other. Requirements for structural redundancy, least weight, operation after any single failure and performance at low temperatures are shown to influence the choice of actuator configuration and the design of assemblies.

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DONG, Qing, Ge Ning XU, and Hui Li REN. "Research on risk of remanufacturing telescopic job structure system under potential multi-failure mode correlation." Journal of Advanced Mechanical Design, Systems, and Manufacturing 11, no. 2 (2017): JAMDSM0028. http://dx.doi.org/10.1299/jamdsm.2017jamdsm0028.

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Le Trung, Chanh, and Toai Nguyen. "EVALUATE THE EFFECTIVENESS OF IMMEDIATE LOADING IMPLANTS WITH OVERDENTURE USING ANKYLOS SYNCONE TELESCOPIC COPINGS FOR THE TREATMENT OF EDENTULOUS MANDIBLES." Volume 8 Issue 4 8, no. 4 (August 2018): 34–41. http://dx.doi.org/10.34071/jmp.2018.4.5.

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Objective: Implant – supported overdentures have been an effective method for the treatment of edentulous mandibles. However, the loading time after implant placement is still controversial. The purpose of the present study was to evaluate the effect of immediate loading implantswith mandibular overdenture using Ankylos Syncone telescopic copings for the treatment of edentulous. Materials and methods: This study was performed on 22 edentulous mandibular patients visiting Department of High Technique, National Hospital of Odonto – Stomatology at Ho Chi Minh city. Each patient received four interforaminal implants. Ankylos Syncone copings systems was used to connect prostheses and implant, which then received immediate loading. The primary response variables were success and failure rate of implants and prostheses. The peri-implant tissue condition and peri-implant crestal bone loss level on radiography were evaluated at six months (T6) and twelve months (T12) postsurgery. Results: There is no peri-implantitis at the follow-up points. The osseointegration rate after 12 months was 100%, while the success rate and survival rate of protheses were 91% and 100% respectively. The peri-implant crestal bone loss on radiography images from baseline (T0) to T6 was 0.07 (±0.22) mm and from T0 to T12 was 0.12 (±0.29) mm. Conclusion: Mandibular rehabilitation usingimmediate loading implant mandibular overdenture with Ankylos Syncone telescopic has shown a high success rate and patient sastisfation over time. Key words: immediate loading, overdenture, edentulous mandibles telescopic copings

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Acharya, Ganesh Bhakta, Anil Shrestha, Hari Bahadur KC, Robin Bahadur Basnet, Aravind Kumar Shah, and Paras Mani Shrestha. "Randomized study comparing safety and efficacy of one shot versus serial metal telescopic dilation technique in percutaneous nephrolithotomy." Journal of Society of Surgeons of Nepal 20, no. 2 (December 31, 2017): 13–19. http://dx.doi.org/10.3126/jssn.v20i2.24376.

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Introduction: Dilation of the track can be achieved by multiple incremental flexible Amplatz type, Alken metal telescoping dilators, or balloon in Percutaneous Nephrolithotomy (PCNL). Balloon dilator is the most expensive method. Both of the incremental dilation techniques are more time consuming with higher failure rates. Hence, a prospective randomized study was conducted to compare the safety and efficacy of “single shot” dilation of the nephrostomy tract by amplatz dilator with serial alken metallic telescopic dilation technique in PCNL. Methods: Of the 138 renal stone patients who underwent PCNL from January 2015 to December 2015, 100 patients were randomized into two groups. Serial tract dilation with alken metallic dilators was used in group A (n=50), and one shot dilation technique in Group B (n=50). The access tract dilation time, success rate, blood loss and complications were evaluated. Results: Both the groups were comparable in terms of mean age, location and size (largest diameter) of the stone (p>0.05). No difference was observed in the procedural success rate between groups A and B (96% v 94% respectively, p=0.64). Mean access time was similar in both groups (5.89+2.67 vs 4.98+2.0 mins, p=0.06). Complications between the groups were not significantly different. There were 6 patients with previous open stone surgery in both the groups. Previous open stone surgery did not impact procedural success rate, access time and complications in both groups. Conclusion: One-shot dilation technique is equally as effective, safe and well tolerated as metal telescopic dilation techniques even in patients with history of ipsilateral open stone surgery.

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Erdal, Ozan A., Baris Gorgun, Ilker A. Sarikaya, and Muharrem Inan. "Retro-patellar approach in telescopic nailing of the tibia in children with osteogenesis imperfecta." Journal of Children's Orthopaedics 15, no. 4 (August 1, 2021): 388–94. http://dx.doi.org/10.1302/1863-2548.15.200263.

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Purpose Telescopic intramedullary nailing (TN) has become the main choice of treatment in children with osteogenesis imperfecta (OI). The classical parapatellar tibial nailing technique poses difficulties in maintaining reduction, insertion of the nail and fluoroscopic imaging. Also, deformities of the proximal tibia in relatively small children with OI can be problematic for tibial nailing. In this report, we present the retro-patellar approach in tibial TN of children with OI as an alternative to the classical approach and report the early radiographic and clinical results of our patients. Methods The nail is inserted through a skin incision proximal to the patella, passing inside the patellofemoral joint while the knee is positioned to 15° to 20° of flexion. In total, 30 tibiae of 15 patients had been operated and were reviewed after at least one year of follow-up. Any complications, such as implant failure, joint damage or instability, malunion, nonunion or refracture, were recorded. Results The mean age of our patients was 8.5 years, and the mean follow-up period was 27 months. There were no complaints involving the knee. All patients showed complete union without any implant failure or refracture. We did not observe any nail protrusion, bending or loss of correction during the procedure. Conclusion The retro-patellar approach for tibial TN appears to be safe and effective in patients with OI. Level of Evidence IV

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Ombres, Luciano, Antonio Iorfida, and Salvatore Verre. "FRCM/SRG - Masonry Joints: Experimental Investigation and Numerical Modelling." Key Engineering Materials 817 (August 2019): 3–8. http://dx.doi.org/10.4028/www.scientific.net/kem.817.3.

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The results of single-lap shear tests, performed on specimens with Fiber Reinforced Cementitious Matrix (FRCM) or Steel Reinforced Grout (SRG) composite strips bonded to masonry unit, are presented in this paper. This study indicates a different type of failure modes occur in PBO FRCM and SRG – masonry joints, respectively. The PBO-FRCM exhibited the typically telescopic failure mode while the SRG shows a slippage of the fibers and fracture of the external matrix layer at the fiber-matrix interface for both the composite systems investigated. Moreover, a 3D numerical model by the commercial code ABAQUS was realized, it is calibrated on the results present in this study. The macro model approach was used with two different bond-slip relationships present in literature. The validity of the numerical model is verified by the comparison with the experimental results in terms of the applied load-global slip and the crack patterns.

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Shuster, Mark, and Mick Deis. "Characterization of triological sealing system components using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS)." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 184–85. http://dx.doi.org/10.1017/s0424820100163381.

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A system approach to solving the tribological problems associated with sealing joints implies comprehensive investigation of all the components. To recognize the root cause of any problem and formulate the required performance for extended reliability we have to evaluate any changes in the system as quantitatively as possible. Any measurable parameters, including geometry, density (porosity), hardness distributions, microstructure and grain size changes observed during routine metallurgical analysis could provide evidence of the root cause of failure. In the head-gasket-block sealing system of the internal combustion engine, the EDS evaluation of the chlorine and sulfur distribution through the head gasket flange fracture in conjunction with analysis of the sludge between the head, block and gasket surfaces pointed to the corrosive nature of the gasket flange cracking.This approach is even more useful for the closed tribological system of telescopic hydraulic cylinders or rotary axle shaft oil seals.

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Signorini, Cesare, Antonella Sola, Andrea Nobili, and Cristina Siligardi. "Lime-cement textile reinforced mortar (TRM) with modified interphase." Journal of Applied Biomaterials & Functional Materials 17, no. 1 (January 2019): 228080001982782. http://dx.doi.org/10.1177/2280800019827823.

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Background: Lack of interphase compatibility between the fabric and the matrix significantly impairs the load-bearing capacity of textile reinforced mortar (TRM). In this study, we consider the application of two inorganic surface coatings for enhancing the interphase bond properties. Methods: Either of two silica-based coatings, namely nano- and micro-silica, were applied to alkali-resistant glass (ARG) and to hybrid carbon–ARG woven fabric. Mechanical performance of TRM reinforced with the uncoated and the coated fabric was compared in uniaxial tensile tests. Results: Mechanical testing provides evidence of a remarkable enhancement in terms of ultimate strength and deformability for the coated specimens. This effect can be ascribed to the improved hydrophilicity of the fibers’ surface and to the activation of pozzolanic reaction at the interphase. In addition, penetration of nano- and microparticles in the bundle of the textile yarns reduces the occurrence of telescopic failure.

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González-Sanz, Guillermo, David Escolano-Margarit, and Amadeo Benavent-Climent. "A New Stainless-Steel Tube-in-Tube Damper for Seismic Protection of Structures." Applied Sciences 10, no. 4 (February 19, 2020): 1410. http://dx.doi.org/10.3390/app10041410.

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This paper investigates a new stainless-steel tube-in-tube damper (SS-TTD) designed for the passive control of structures subjected to seismic loadings. It consists of two tubes assembled in a telescopic configuration. A series of slits are cut on the walls of the exterior tube in order to create a series of strips with a large height-to-width ratio. The exterior tube is connected to the interior tube so that when the brace-type damper is subjected to forced axial displacements, the strips dissipate energy in the form of flexural plastic deformations. The performance of the SS-TTD is assessed experimentally through quasi-static and dynamic shaking table tests. Its ultimate energy dissipation capacity is quantitatively evaluated, and a procedure is proposed to predict the failure. The cumulative ductility of the SS-TTD is about 4-fold larger than that reported for other dampers based on slit-type plates in previous studies. Its ultimate energy dissipation capacity is 3- and 16-fold higher than that of slit-type plates made of mild steel and high-strength steel, respectively. Finally, two hysteretic models are investigated and compared to characterise the hysteretic behaviour of the SS-TTD under arbitrarily applied cyclic loads.

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Siddiqi, Asif. "Shaping the World." Comparative Studies of South Asia, Africa and the Middle East 41, no. 1 (May 1, 2021): 41–55. http://dx.doi.org/10.1215/1089201x-8916932.

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Abstract This article explores the biography of a network of Soviet telescopic cameras stationed across the African Sahel during the Cold War. Through joint Soviet-African cooperative programs, scientists used these advanced cameras in Egypt, Somalia, Mali, the Sudan, and Chad to photograph satellites flying overhead to gather data to produce a new model of the Earth, one that Soviet scientists hoped would be an alternative to Western models. I argue that these technical artifacts in Africa, connected into a single global network, represented examples of “infrastructural irruptions” of Cold War technopolitics into African geography, wherein the superpowers placed networked technologies inside postcolonial spaces for the collection of data. Although these technologies were nominally Soviet in origin, the story could also be read as one of Africans who invested their geography with agency in the production of scientific knowledge. Like the socialist moment in Africa and indeed the Soviet Union itself, this camera network no longer exists, its data compromised and its material imprint disappeared. But this “failure” should not blind us to the immanent power of possibility embedded in this incomplete project. I argue that this combination of unbounded aspiration and incomplete materiality was a powerful manifestation of the African-Soviet Modern.

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Street, R. A., T. A. Lister, Y. Tsapras, A. Shporer, F. B. Bianco, B. J. Fulton, D. A. Howell, et al. "A Global Robotic Telescope Network for Time-Domain Science." Proceedings of the International Astronomical Union 7, S285 (September 2011): 408–10. http://dx.doi.org/10.1017/s174392131200124x.

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AbstractLas Cumbres Observatory Global Telescope Network (LCOGT) is currently building a new kind of general-purpose astronomical facility: a fully robotic network of telescopes of 2m, 1m and 0.4m apertures and homogeneous instrumentation. A pan-network approach to scheduling (rather than per individual telescope) offers redundancy in the event of poor weather or technical failure, as well as the ability to observe a target around the clock. Here we describe the network design and instrumentation under development, together with the main science programmes already being lead by LCOGT staff.

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Panagiotopoulou, V. C., K. Davda, H. S. Hothi, J. Henckel, A. Cerquiglini, W. D. Goodier, J. Skinner, A. Hart, and P. R. Calder. "A retrieval analysis of the Precice intramedullary limb lengthening system." Bone & Joint Research 7, no. 7 (July 2018): 476–84. http://dx.doi.org/10.1302/2046-3758.77.bjr-2017-0359.r1.

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Objectives The Precice nail is the latest intramedullary lengthening nail with excellent early outcomes. Implant complications have led to modification of the nail design. The aim of this study was to perform a retrieval study of Precice nails following lower-limb lengthening and to assess macroscopical and microscopical changes to the implants and evaluate differences following design modification, with the aim of identifying potential surgical, implant, and patient risk factors. Methods A total of 15 nails were retrieved from 13 patients following lower-limb lengthening. Macroscopical and microscopical surface damage to the nails were identified. Further analysis included radiology and micro-CT prior to sectioning. The internal mechanism was then analyzed with scanning electron microscopy and energy dispersive x-ray spectroscopy to identify corrosion. Results Seven male and three female patients underwent 12 femoral lengthenings. Three female patients underwent tibial lengthening. All patients obtained the desired length with no implant failure. Surface degradation was noted on the telescopic part of every nail design, less on the latest implants. Microscopical analysis confirmed fretting and pitting corrosion. Following sectioning, black debris was noted in all implants. The early designs were found to have fractured actuator pins and the pin and bearings showed evidence of corrosive debris. The latest designs showed evidence of biological deposits suggestive of fluid ingress within the nail but no corrosion. Conclusion This study confirms less internal corrosion following modification, but evidence of titanium debris remains. We recommend no change to current clinical practice. However, potential reuse of the Precice nail, for secondary limb lengthening in the same patient, should be undertaken with caution. Cite this article: V. C. Panagiotopoulou, K. Davda, H. S. Hothi, J. Henckel, A. Cerquiglini, W. D. Goodier, J. Skinner, A. Hart, P. R. Calder. A retrieval analysis of the Precice intramedullary limb lengthening system. Bone Joint Res 2018;7:476–484. DOI: 10.1302/2046-3758.77.BJR-2017-0359.R1.

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Antoniadou, Ifigeneia, Keith Worden, Graeme Manson, Nikolaos Dervilis, S. G. Taylor, and Charles R. Farrar. "Damage Detection in RAPTOR Telescope Systems Using Time-Frequency Analysis Methods." Key Engineering Materials 588 (October 2013): 43–53. http://dx.doi.org/10.4028/www.scientific.net/kem.588.43.

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The RAPTOR telescope systems are astronomical observatories that operate in remote locations in New Mexico searching for astrophysical transients called gamma-ray bursts. Their operating condition should remain at good levels in order to have accurate observations. Currently, the first component of the RAPTOR telescopes to fail is a capstan driving mechanism that operates in a run-to failure mode. The capstans wear relatively frequently because of their manufacturing material and can cause damage to other more expensive components, such as the drive wheels and the telescope optics. Monitoring the condition of these systems seems a reasonable solution since the unpredictable rate at which the capstans experience wear, in combination with the remote locations and high duty cycles of these telescope systems, make it unprofitable to choose a strategy of replacing the capstans at chosen intervals. Experimental tests of the telescope systems reported here recorded vibration signals during clockwise and counterclockwise rotations, similar to a motion known as "homing-sequence". The Empirical Mode Decomposition (EMD) method in combination with the Hilbert Transform (HT) and a new alternative method for the estimation of the instantaneous features of a signal that applies an energy tracking operator, called Teager-Kaiser Energy operator, and an energy separation algorithm to the data being analysed, are the time-frequency analysis methods used for analysis here.

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Mesarcik, Michael, Albert-Jan Boonstra, Christiaan Meijer, Walter Jansen, Elena Ranguelova, and Rob V. van Nieuwpoort. "Deep learning assisted data inspection for radio astronomy." Monthly Notices of the Royal Astronomical Society 496, no. 2 (May 28, 2020): 1517–29. http://dx.doi.org/10.1093/mnras/staa1412.

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ABSTRACT Modern radio telescopes combine thousands of receivers, long-distance networks, large-scale compute hardware, and intricate software. Due to this complexity, failures occur relatively frequently. In this work, we propose novel use of unsupervised deep learning to diagnose system health for modern radio telescopes. The model is a convolutional variational autoencoder (VAE) that enables the projection of the high-dimensional time–frequency data to a low-dimensional prescriptive space. Using this projection, telescope operators are able to visually inspect failures thereby maintaining system health. We have trained and evaluated the performance of the VAE quantitatively in controlled experiments on simulated data from HERA. Moreover, we present a qualitative assessment of the model trained and tested on real LOFAR data. Through the use of a naïve SVM classifier on the projected synthesized data, we show that there is a trade-off between the dimensionality of the projection and the number of compounded features in a given spectrogram. The VAE and SVM combination scores between 65 per cent and 90 per cent accuracy depending on the number of features in a given input. Finally, we show the prototype system-health-diagnostic web framework that integrates the evaluated model. The system is currently undergoing testing at the ASTRON observatory.

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Landau, Robert. "Intelligent Fault Diagnosis at the Australia Telescope." Publications of the Astronomical Society of Australia 11, no. 2 (August 1994): 180–87. http://dx.doi.org/10.1017/s132335800001986x.

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AbstractThe Fault Diagnosis Expert System for the Australia Telescope analyses ~12000 items of monitor data every minute that report the health and stability of specific components and signal pathways in the array. These data are divided into signatures which are matched against signatures of known failure modes to diagnose problems with the array. Knowledge about many of the failures is acquired by generating them in earlier tests. The system keeps a six-hour history of the detailed behaviour of all monitor data as well as the visibilities. It archives the data in half-hour intervals, characterising the interval with a small set of robust statistical estimators. An interactive graphical user interface allows the simultaneous display of twenty-four histories of either the 6-hour data or one week of the characterised data, together with options for plotting one history against another and for calculating their robust regression.

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Khristoforov, Evgeniy, Nataliya Sakovich, and Aleksandr Kuznecov. "SAFETY SUPPORT IN TRANSPORT CONSTRUCTION MACHINERY WITH HYDRAULIC DRIVE." Bulletin of Bryansk state technical university 2021, no. 7 (June 16, 2021): 38–49. http://dx.doi.org/10.30987/1999-8775-2021-7-38-49.

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Work purpose: the investigation of transport process safety in construction industry of the Bryansk region, the substantiation of reasons, factors and circumstances of accidents in the construction companies of the region, the substantiation of the impact of hydraulic drive unit failures upon safety of transport construction machinery with the hydraulic drive with the purpose of driver safety. Investigation problem: on the basis of the obtained results of the safety investigations of transport processes, reasons defined, revealed injury factors of drivers during the operation of the load flat car hydraulic drive of transport means to develop motion parameters of the “hydraulic drive-load flat car” system which will not allow arising oscillations of the system resulting in hydraulic drive failure arising which has influence upon driver’s work safety. The investigations were carried out on the basis of a system analysis of accident examinations in the regional construction industry which on the basis of statistical data allows the defining safety state of transport construction machinery. By means of investigations it is defined that 90% of transport construction machines are equipped with a hydraulic drive. In the hydraulic drive the most significant element is a hydraulic cylinder – the most loaded element performing all basic operations of a working process of loading and unloading. In the hydraulic drive there is used a telescopic hydraulic cylinder in which during operation there are revealed design-production defects (DPD) which result in injury of machine service personnel. One of DPD manifestations is oscillation formation in the hydraulic drive which results in the destruction of hydraulic cylinder attachment fitting. It is defined that the support of hydraulic drive reliability and safety is a difficult problem which needs a complex solution still at designing and creation, and during the operation. The complexity of the problem causes the necessity of design and operation parameter optimization, in the first place, that of an executing hydraulic cylinder of the hydraulic drive with the use of mathematical modeling. The review of the mathematical modeling methods of hydraulic cylinder parameters allows drawing the conclusion that the existing methods have many assumptions and do not allow creating completely reliable and safe transport construction engineering. The investigation novelty consists in the offered procedure for the solution of motion equations of the “hydraulic drive – load flat car” system which allows calculating the motion system parameters, defining the development of system oscillation above critical able to destruct a fitting unit of the hydraulic cylinder to the load flat car. Conclusion. The algorithm offered for the solution of mathematical equations allows making a conclusion on the stability and safety of the “hydraulic cylinder – load flat car” system, finding optimum values of motion parameters at any time moment of a transitional process.

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Paramore, Christopher G., Curtis A. Dickman, and Volker K. H. Sonntag. "Radiographic and clinical follow-up review of Caspar plates in 49 patients." Journal of Neurosurgery 84, no. 6 (June 1996): 957–61. http://dx.doi.org/10.3171/jns.1996.84.6.0957.

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✓ Although they are excellent clinical tools, Caspar anterior cervical plates have not been studied closely with regard to their mechanisms of failure. As more extensive operations are contemplated on older, sicker patients, it is imperative to know when a plating system might be prone to failure and what the mechanism of that failure might be. Therefore, the authors reviewed 49 patients undergoing Caspar plate placement in whom sufficient radiographs were obtained to determine if the fate of the hardware was related to the patient's age, type of operation, and the length of construct. Eleven of 49 patients suffered hardware failure, defined as any amount of screw backout or breakage, plate pullout, or pseudarthrosis. Four patients underwent hardware removal; one underwent posterior fusion for pseudarthrosis. Only two required treatment in a halo brace. There was an eventual fusion rate of 100%, including one fibrous union, and one of the patients who underwent repeat surgery was lost to follow-up review. No graft extrusions or new neurological deficits were incurred as a result of hardware failure. Plate length predicted plate failure in a statistically significant manner. Increasing age and reoperation correlated with plate failure but were not statistically significant in this small number of patients. Telescoping of the bone graft and vertebral bodies, with concomitant migration of the plate and slippage of the screws, was common. However, telescoping was more profound in the group in which the plates failed. The authors conclude that Caspar plate failures are more likely to occur in the elderly and in patients who need longer constructs. Bone fusion can be expected even when the hardware loosens.

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Zheng, Lingyu, Daxu Zhang, Long Wang, Aman Shrestha, Zhensen Song, Shengbin Gao, Teng Xu, and Mingming Xu. "Lightweight cylindrical composite shell structures to support optical instruments in extremely large telescopes: A case study." Science Progress 104, no. 3 (July 2021): 003685042110361. http://dx.doi.org/10.1177/00368504211036147.

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Aiming at the issues of heavy weight and insufficient structural performance of optical instrument supporting structures in extremely large telescopes, the Wide-Field Optical Spectrograph (WFOS) of the Thirty Meter Telescope (TMT) was taken as a case to study. In order to develop lightweight structures which satisfies the design requirements for mass and stiffness, a design scheme of cylindrical composite shells supporting structure was proposed and their finite element models were developed. A size optimisation and a ply sequence optimisation of the composite structure were carried out. The structures before and after optimisation were evaluated from the aspects of mass, displacement, failure index and fundamental frequency. After the optimised design, the mass of the optimised WFOS cylindrical composite shell structure is reduced to approximately 50%, but its maximum displacement (0.513 mm) and fundamental frequency (8.275 Hz) are nearly unchanged. The study indicates that a cylindrical composite shell structure is an efficient structural form for large optical instruments.

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Morelli, Piero. "On the Buckling Behaviour of Telescopic Hydraulic Cylinders." Key Engineering Materials 417-418 (October 2009): 281–84. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.281.

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Telescopic cylinders are generally employed as linear actuators, when the desired moving span is several times the length of the closed device, like in cargo trucks lifting applications, for instance. During the active phase of the actuation, hydraulic power is normally used to feed pressu-rized fluid inside the cylinder, thus providing the progressive extension of the cylinder ele-ments and the required operative axial thrust. In this condition, therefore, cylinders must bear external compressive loadings in an increasingly slenderness configuration, which can give rise to buckling failures. In this study, experimental measurements of the limiting axial loadings of telescopic cylind-ers, in full extended conditions, have been performed both in laboratory and during real oper-ations on the field. The strains of the material in the critical sections and the lateral deflec-tions of the tested structures have been recorded as a function of the applied loads. The re-sults of this investigation are presented and discussed, in order to identify the signals of inci-pient buckling and find out the ultimate load carrying capabilities of this kind of components.

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McCray, Patrick (W Patrick). "What Makes a Failure? Designing a New National Telescope, 1975-1984." Technology and Culture 42, no. 2 (2001): 265–91. http://dx.doi.org/10.1353/tech.2001.0076.

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SAITOH, S., and Y. NAKATSUCHI. "Arterial Grafting with the Telescoping Anastomotic Technique for Arterial Defects." Journal of Hand Surgery 19, no. 4 (August 1994): 461–65. http://dx.doi.org/10.1016/0266-7681(94)90211-9.

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An arterial graft was taken from the left femoral artery of the rat and grafted into the right femoral artery using the telescoping anastomotic technique at both the proximal and distal anastomoses to compare the patency rate with that of the vein grafts interposed into the arterial defect with the same telescoping technique. The time required for each anastomosis was about 10 minutes and all of the 31 grafts remained patent without application of xylocaine, yielding a higher patency rate than the vein grafts interposed in an arterial defect. The telescoping technique proved to be so dependable that it could be used at least twice in an artery. Inserting one vessel stump into another using the telescoping technique may not itself be responsible for the failure of vein grafts interposed in an arterial defect, but distortion of the slack venous wall of the graft by high arterial blood pressure is.

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Howse, H. Derek, and Patrick Moore. "The Role of the Amateur in Modern Astronomy." International Astronomical Union Colloquium 98 (1988): 200. http://dx.doi.org/10.1017/s0252921100092897.

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AbstractThis contribution dealt with the need for international coordination between amateur astronomers and the failure of the IUAA (International Union of Amateur Astronomers) to meet this need. [The substance of this contribution was given in Sky & Telescope,73, 482 (1987 November).The text was not received. – Eds.]

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Thornton, Earl A., David L. Eby, and Peter W. Chung. "Torsional Buckling of the Hubble Space Telescope Solar Arrays." International Journal of Space Structures 13, no. 2 (June 1998): 65–74. http://dx.doi.org/10.1177/026635119801300202.

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The buckling behavior of a flexible rolled-up solar array used on the Hubble Space Telescope (HST) is investigated analytically and experimentally. Analytically, the solar array is modeled assuming the booms are linear, elastic beams of open cross-section, and the solar blanket is represented as an inextensible membrane. The analyses determine critical buckling loads for flexure and torsion. The behavior of the solar array is also investigated by experiments conducted using a model solar array with (1) closed cross-section booms, and (2) tubular booms like those used on the HST. The analyses and experiments show that the Hubble's solar arrays were deployed with a preload that caused them to buckle in torsion. Based on the study, an hypothesis is suggested for the failure of the solar array's booms that was discovered by the astronauts in 1993.

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DUAN, JIN, ZHI-HAI XIANG, and MING-DE XUE. "THERMAL–DYNAMIC COUPLING ANALYSIS OF LARGE SPACE STRUCTURES CONSIDERING GEOMETRIC NONLINEARITY." International Journal of Structural Stability and Dynamics 08, no. 04 (December 2008): 569–96. http://dx.doi.org/10.1142/s0219455408002806.

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In this paper, a beam element is derived for the thermal–dynamic coupling analysis by the updated Lagrangian formulation. The nodal transformation matrix of the element is obtained by dividing the rigid body rotation of the beam element into the relative translational displacements and axial rotation. With this transformation matrix, the interaction between the structural deformation and the absorbed heat flux can be formulated and the thermal–structural coupling effect is thus considered. The validity of the proposed method is illustrated by comparing the obtained results with the numerical, analytical or experimental results available in the literature. Then the method is employed to analyze the thermal–structural responses of the Hubble Space Telescope (HST) solar array. From the results, a reasonable explanation can be given for the failure of the telescope in 1990.

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Parker, Q. A., S. Phillipps, D. H. Morgan, D. F. Malin, K. S. Russell, M. Hartley, and A. Savage. "Use of Kodak Tech-Pan Film at the Ukstu." Symposium - International Astronomical Union 161 (1994): 129–39. http://dx.doi.org/10.1017/s0074180900047203.

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Kodak Technical Pan (Tech Pan) emulsion is an extremely fine grained, high resolution, panchromatic negative film with extended red sensitivity. It has been produced under this name since about 1980 (Kodak P–255, 1981) and is available on Kodak's Estar base in a number of thicknesses and sizes. The thick ∗∗base Tech Pan is designated 4415 and has been used with great success by the amateur astronomical community for many years (e.g. Martys 1991). Its astronomical potential was recognised early by Everhart (1981). However, tests at professional telescopes (e.g. West et al. 1981) and early sensitometer tests at the UK Schmidt Telescope (UKST) in 1981 and 1987 were discontinued when the glass and film samples did not respond well to normal hypersensitisation techniques. These and other difficulties led to a lack of interest among the professional astronomical community until quite recently (Russell et al. 1992; Parker & Malin 1992). The first successful use of 14 × 14 inch hypered Tech-Pan 4415 film in the UKST was in March 1991. Films were obtained which exhibited excellent image quality and resolution. Furthermore, in good seeing these appeared to be about 1 magnitude deeper than the equivalent IIIa-F emulsion on glass but with considerably lower grain noise. This result was achieved because two main problems associated with Tech-Pan and film use in the UKST have been resolved. These were: 1) obtaining Tech-Pan film with long exposure speed sufficient for deep astronomical photography (i.e. reduction of low intenstiy reciprocity failure); 2) overcoming the practical difficulties of mounting large-format flexible film at the UKST's curved focal surface.

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Bozza, Cristiano. "KM3NeT Acquisition Control." EPJ Web of Conferences 207 (2019): 06008. http://dx.doi.org/10.1051/epjconf/201920706008.

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The multi-site nature of the KM3NeT neutrino observatory in the Mediterranean Sea has influenced the development and evolution of its acquisition control software. It is flexible and portable. The same programs are used in data-taking shore stations of neutrino telescopes as well as in testing sites for detector components at different stages of the integration. Flexibility is obtained through high modularity and tight integration with the central database system. The software architecture can be defined as “maximally disconnected” to ensure that no “single point of failure” exists. The most recent development is dynamic resource provisioning and failover, to automatically cope with the possible event of a hardware failure of one or more data taking servers or network elements.

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de Andrade, Guilherme Cabral, Helvercio P. Alves, Valter Clímaco, Eduardo Pereira, Alexandre Lesczynsky, and Michel E. Frudit. "Two-stage reconstructive overlapping stent LEO+ and SILK for treatment of intracranial circumferential fusiform aneurysms in the posterior circulation." Interventional Neuroradiology 22, no. 5 (July 11, 2016): 516–23. http://dx.doi.org/10.1177/1591019916656475.

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Intracranial circumferential fusiform aneurysms of the posterior circulation involving arterial branches or perforating vessels are difficult to treat. This article shows an endovascular reconstruction technique not yet described, using a telescoping self-expandable stent (LEO+) and flow-diverter device (SILK) at different surgical times. Two patients with circumferential fusiform aneurysm, one being an aneurysm of the segments P2 and P3 of the posterior cerebral artery, diagnosed after a headache, and the other a partially thrombosed aneurysm of the lower basilar artery, diagnosed following ischemia of the brain stem. Endovascular treatment was performed by means of a vascular reconstruction technique that used at different surgical times: overlapping; a telescoped self-expandable stent, LEO+; and a flow-diverter device, SILK. Angiographic control was carried out at 6 and 12 months, to evaluate arterial patency, flow maintenance in the arterial branches and perforating vessels, and thrombosis of the aneurysm. The combined use at different surgical times of the self-expandable stent and flow-diverter device was technically successful in both patients. There were no complications during the procedure, nor in the long-term follow-up with full arterial vascular reconstruction, maintenance of cerebral perfusion and complete aneurysm occlusion at the 6- and 12-month angiographic follow-up. There was no aneurysm recanalization nor intra-stent stenosis. Circumferential fusiform aneurysm of the posterior circulation involving arterial branches or perforating vessels to the brain stem may be treated with this arterial reconstruction technique at different surgical times, using the self-expandable stent called LEO+ and the flow-diverter device SILK, minimizing the risk of complications and failure of the endovascular technique, with the potential for arterial reconstruction with thrombosis of the aneurysmatic sac, as well as flow maintenance in the eloquent arteries, in this type of cerebral aneurysm.

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Bliven, E., S. Sandriesser, P. Augat, C. von Rüden, and S. Hackl. "Biomechanical evaluation of locked plating fixation for unstable femoral neck fractures." Bone & Joint Research 9, no. 6 (June 2020): 314–21. http://dx.doi.org/10.1302/2046-3758.96.bjr-2019-0331.r1.

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Aims Evaluate if treating an unstable femoral neck fracture with a locking plate and spring-loaded telescoping screw system would improve construct stability compared to gold standard treatment methods. Methods A 31B2 Pauwels’ type III osteotomy with additional posterior wedge was cut into 30 fresh-frozen femur cadavers implanted with either: three cannulated screws in an inverted triangle configuration (CS), a sliding hip screw and anti-rotation screw (SHS), or a locking plate system with spring-loaded telescoping screws (LP). Dynamic cyclic compressive testing representative of walking with increasing weight-bearing was applied until failure was observed. Loss of fracture reduction was recorded using a high-resolution optical motion tracking system. Results LP constructs demonstrated the highest mean values for initial stiffness and failure load. LP and SHS constructs survived on mean over 50% more cycles and to loads 450 N higher than CS. During the early stages of cyclic loading, mean varus collapse of the femoral head was 0.5° (SD 0.8°) for LP, 0.7° (SD 0.7°) for SHS, and 1.9° (SD 2.3°) for CS (p = 0.071). At 30,000 cycles (1,050 N) mean femoral neck shortening was 1.8 mm (SD 1.9) for LP, 2.0 mm (SD 0.9) for SHS, and 3.2 mm (SD 2.5) for CS (p = 0.262). Mean leg shortening at construct failure was 4.9 mm (SD 2.7) for LP, 8.9 mm (SD 3.2) for SHS, and 7.0 mm (SD 4.3) for CS (p = 0.046). Conclusion Use of the LP system provided similar (hip screw) or better (cannulated screws) biomechanical performance as the current gold standard methods suggesting that the LP system could be a promising alternative for the treatment of unstable fractures of the femoral neck. Cite this article: Bone Joint Res 2020;9(6):314–321.

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Bogaards, Matthijs. "Microscope or Telescope? The Study of Democratisation across World Regions." Political Studies Review 16, no. 2 (June 29, 2016): 125–35. http://dx.doi.org/10.1177/1478929916645360.

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This review article brings together six recent books on democratisation. They cover Africa, Latin America, the Middle East, East Central Europe and the Balkans, Eurasia, and East and South East Asia. The review asks what we can learn from reading about democratisation in different parts of the world. The aim is twofold: to identify regionally specific processes of democratisation and to explore cross-regional commonalities. When viewed in combination, these regional studies of democratisation reveal the limitations of area studies and the need for comparative area studies. Cheeseman N (2015) Democracy in Africa: Successes, Failures, and the Struggle for Political Reform. Cambridge: Cambridge University Press. Hale H (2015) Patronal Politics: Eurasian Regime Dynamics in Comparative Perspective. Cambridge: Cambridge University Press. Hsin-Huang MH (ed.) (2014) Democracy or Alternative Political Systems in Asia: After the Strongmen. London: Routledge. Mainwaring S and Pérez-Liñán A (2013) Democracies and Dictatorship in Latin America: Emergence, Survival, and Fall. Cambridge: Cambridge University Press. Petrovic M (2013) The Democratic Transition of Post-Communist Europe: In the Shadow of Communist Differences and Uneven Europeanisation. Basingstoke: Palgrave Macmillan. Sadiki L (ed.) (2015) Routledge Handbook of the Arab Spring: Rethinking Democratization. London: Routledge.

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Levine, Robert S., Barbara J. Kilbourne, Maureen Sanderson, Mary K. Fadden, Maria Pisu, Jason L. Salemi, Maria Carmenza Mejia de Grubb, et al. "Lack of validity of self-reported mammography data." Family Medicine and Community Health 7, no. 1 (January 2019): e000096. http://dx.doi.org/10.1136/fmch-2018-000096.

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This qualitative literature review aimed to describe the totality of peer-reviewed scientific evidence from 1990 to 2017 concerning validity of self-reported mammography. This review included articles about mammography containing the words accuracy, validity, specificity, sensitivity, reliability or reproducibility; titles containing self-report, recall or patient reports, and breast or ‘mammo’; and references of identified citations focusing on evaluation of 2-year self-reports. Of 45 publications meeting the eligibility criteria, 2 conducted in 1993 and 1995 at health maintenance organisations in Western USA which primarily served highly educated whites provided support for self-reports of mammography over 2 years. Methodological concerns about validity of self-reports included (1) telescoping, (2) biased overestimates particularly among black women, (3) failure to distinguish screening and diagnostic mammography, and (4) failure to address episodic versus consistent mammography use. The current totality of evidence supports the need for research to reconsider the validity of self-reported mammography data as well as the feasibility of alternative surveillance data sources to achieve the goals of the Healthy People Initiative.

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Manni, Antonio, Mauro Cozzani, Laura Mazzotta, Valerio Pierpaolo Fiore, and Sabrina Mutinelli. "Acrylic splint Herbst and Hanks telescoping Herbst: A retrospective study of emergencies, retreatments, treatment times and failures." International Orthodontics 12, no. 1 (March 2014): 100–110. http://dx.doi.org/10.1016/j.ortho.2013.12.015.

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Kawamura, Tadashi, Hiroaki Minehara, Ryo Tazawa, Terumasa Matsuura, Rina Sakai, and Masashi Takaso. "Biomechanical Evaluation of Extramedullary Versus Intramedullary Reduction in Unstable Femoral Trochanteric Fractures." Geriatric Orthopaedic Surgery & Rehabilitation 12 (January 1, 2021): 215145932199861. http://dx.doi.org/10.1177/2151459321998611.

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Introduction: The failure rate of operations involving the cephalomedullary nail technique for unstable femoral trochanteric fractures is 3-12%. Changing the reduction strategy may improve the stability. This study aimed to confirm whether reducing the proximal fragment with the medial calcar contact, as opposed to utilizing an intramedullary reduction, would improve the stability of such fractures. Materials and Methods: The unstable femoral trochanteric fracture model was created with fixation by cephalomedullary nails in 22 imitation bones. The 2 reduction patterns were as follows: one was with the proximal head-neck fragment external to the distal bone in the frontal plane and anterior in the sagittal plane as “Extramedullary,” while the other was the opposite reduction position, that is, bone in the frontal plane and sagittal plane as “Intramedullary.” We evaluated the tip-apex distance, compression stiffness, change in femoral neck-shaft angle, amount of blade telescoping, and diameter of the distal screw hole after the compression test. Statistical analysis was conducted using the Mann-Whitney U test. Results: No significant differences were seen in compression stiffness ( p = 0.804) and femoral neck-shaft angle change ( p = 0.644). Although the “Extramedullary” tip-apex distance was larger than the “Intramedullary” distance ( p = 0.001), it indicated clinically acceptable lengths. The amount of blade telescoping and the distal screw hole diameter were significantly larger in “Intramedullary” than in “Extramedullary” ( p < 0.001, p = 0.019, respectively). Our results showed that “Intramedullary” had significantly larger blade telescoping and distal screw hole diameters than “Extramedullary,” and contrary to our hypothesis, no significant differences were seen in compression stiffness and femoral neck-shaft angle change. Conclusions: As opposed to the “Intramedullary” reduction pattern, the biomechanical properties of the “Extramedullary” reduction pattern improved stability during testing and decreased sliding.

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Crawford, Jarret T., Allison Fournier, and John Ruscio. "Does Subjective SES Moderate the Effect of Money Priming on Socioeconomic System Support? A Replication of Schuler and Wänke (2016)." Social Psychological and Personality Science 10, no. 1 (November 30, 2017): 103–9. http://dx.doi.org/10.1177/1948550617740941.

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Findings that money priming increases socioeconomic system support have proven difficult to replicate. Schuler and Wänke found that subjective socioeconomic status (SES) moderates money priming effects on system justification and belief in a just world. We conducted three preregistered replications of this research, with sample sizes 3 times those of the original studies. Replication 1 was a conceptual replication that combined elements from the original two studies, and Replications 2 and 3 were close replications of Studies 1 and 2, respectively. None of the four subjective SES × Money Prime interaction effects tested were statistically significant, and only one of the four survived a “small telescopes” analysis. We discuss reasons for our general failure to replicate the original findings and implications for money priming effects.

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Leitherer, Claus. "Massive Star Formation in the Ultraviolet Observed with the Hubble Space Telescope." Galaxies 8, no. 1 (February 9, 2020): 13. http://dx.doi.org/10.3390/galaxies8010013.

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Spectroscopic observations of a massive star formation in the ultraviolet and their interpretation are reviewed. After a brief historical retrospective, two well-studied resolved star clusters and the surrounding H II regions are introduced: NGC 2070 in the Large Magellanic Cloud and NGC 604 in M33. These regions serve as a training set for studies of more distant clusters, which can no longer be resolved into individual stars. Observations of recently formed star clusters and extended regions in star-forming galaxies in the nearby universe beyond the Local Group are presented. Their interpretation relies on spectral synthesis models. The successes and failures of such models are discussed, and future directions are highlighted. I present a case study of the extraordinary star cluster and giant H II region in the blue compact galaxy II Zw 40. The review concludes with a preview of two upcoming Hubble Space Telescope programs: ULLYSES, a survey of massive stars in nearby galaxies, and CLASSY, a study of massive star clusters in star-forming galaxies.

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Kilian, Miroslav, Peter Csörgő, Marian Šajter, Pavel Šimkovic, Silvia Vajcziková, and Radoslav Zamborský. "Locking Plate Fixation with Multiple Telescoping Sliding Screws for Femoral Neck Fractures." Ortopedia Traumatologia Rehabilitacja 20, no. 6 (December 31, 2018): 493–98. http://dx.doi.org/10.5604/01.3001.0012.9705.

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Background. Non-displaced femoral neck fractures are mostly treated with internal fixation, while in displaced fractures this surgical option is under debate and the benefits are still not clear. The purpose of this study was to identify the factors that affect the treatment of non-displaced and displaced hip fractures using a head-preserving plate. Material and methods. From August 2011 to May 2015, we reviewed eighty-two adult patients who had sustained undisplaced and displaced intracapsular femoral neck fracture treated with a locking plate system with telescoping sliding screws. Fracture reduction, healing rate and implant related complications were primary objectives. Other complications (e.g. avascular necrosis, nonunion, hematoma, infection) and revision surgery were recorded as well. Results. According to the Garden classification system, a total of 51.2% fractures were classified as non-displaced (type 1 and 2) and 48.8% were displaced fractures (type 3 and 4). Anatomic reduction was achieved in 58.5% and valgus in 41.5% of patients and it did not influence the healing. Varus reduction was not observed in any case. The total average complication rate was 18.1%, where screw cutout was the most frequent complication (8.5%). The timing of surgery did not affect the healing of femoral neck fractures. Age over 60 years combined with a displaced fracture was associated with impaired healing potential and a higher complication rate. Revision surgery was performed in 17.1% of patients, mainly those with displaced fractures. Conclusions. 1. The use of a locking plate system with telescoping sliding screws was associated with lower rates of postoperative complications in undisplaced, but also in displaced femoral neck fractures in patients younger 60 years. 2. Patients over 60 years with displaced fractures were more likely to have healing problems and implant failure.

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BULTER, C. "P2775 The use of a dual telescoping guide catheter system for coronary sinus side branch cannulation in heart failure patients." European Heart Journal 24, no. 5 (March 2003): 520. http://dx.doi.org/10.1016/s0195-668x(03)95553-9.

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Dever, Joyce A., Kim K. de Groh, Bruce A. Banks, Jacqueline A. Townsend, Janet L. Barth, Shaun Thomson, Teri Gregory, and William Savagek. "Environmental Exposure Conditions for Teflon® Fluorinated Ethylene Propylene on the Hubble Space Telescope." High Performance Polymers 12, no. 1 (March 2000): 125–39. http://dx.doi.org/10.1088/0954-0083/12/1/310.

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The outer layer of Teflon® fluorinated ethylene propylene (FEP) multi-layer insulation (MLI) on the Hubble Space Telescope (HST) was observed to be significantly cracked at the time of the Second HST Servicing Mission (SM2), 6.8 years after HST was launched into low Earth orbit (LEO). Comparatively minor embrittlement and cracking were also observed in the FEP materials retrieved from solar-facing surfaces on the HST at the time of the First Servicing Mission (3.6 years exposure). After SM2, a failure review board was convened to address the problem of degradation of MLI on the HST. In order for this board to determine possible degradation mechanisms, it was necessary to consider all environmental constituents to which the FEP MLI surfaces were exposed. Based on measurements and various models, the environmental exposure conditions for the FEP surfaces on the HST were estimated, including: the number and temperature ranges of thermal cycles; equivalent sun hours; fluence and absorbed radiation dose of x-rays, trapped protons and electrons and plasma electrons and protons; and atomic oxygen (AO) fluence. This paper presents the environmental exposure conditions for FEP on the HST, briefly describing the possible roles of the environmental factors in the observed FEP embrittlement and providing references to the published works which describe in detail testing and analysis related to FEP degradation on the HST.

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Shostak, G. Seth. "Searching for sentience: SETI today." International Journal of Astrobiology 2, no. 2 (April 2003): 111–14. http://dx.doi.org/10.1017/s1473550403001502.

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For more than four decades, a small group of researchers has sought to find evidence of extraterrestrial intelligence in situ, by detecting microwave signals that would betray its existence. Despite the failure to find these signals so far, there is continued and even accelerated effort to press the search. Recent advances include greater emphasis on experiments at optical wavelengths, and the construction of a new radio telescope that is deliberately designed for such reconnaissance. In addition to these instrumental improvements, several strategies have been proposed that might better the chances of ‘looking in the right place, at the right time’. This review of the current state of SETI research concludes with a speculative look at the nature of the sought-for extraterrestrials, and when it is likely we might find them.

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Aydin, Levent, Olgun Aydin, H. Seçil Artem, and Ali Mert. "Design of dimensionally stable composites using efficient global optimization method." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 233, no. 2 (August 17, 2016): 156–68. http://dx.doi.org/10.1177/1464420716664921.

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Abstract:

Dimensionally stable material design is an important issue for space structures such as space laser communication systems, telescopes, and satellites. Suitably designed composite materials for this purpose can meet the functional and structural requirements. In this paper, it is aimed to design the dimensionally stable laminated composites by using efficient global optimization method. For this purpose, the composite plate optimization problems have been solved for high stiffness and low coefficients of thermal and moisture expansion. Some of the results based on efficient global optimization solution have been verified by genetic algorithm, simulated annealing, and generalized pattern search solutions from the previous studies. The proposed optimization algorithm is also validated experimentally. After completing the design and optimization process, failure analysis of the optimized composites has been performed based on Tsai–Hill, Tsai–Wu, Hoffman, and Hashin–Rotem criteria.

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Grazette, Luanda P., and Jeffrey J. Goldberger. "Addressing the sudden cardiac death conundrum in heart failure with preserved ejection fraction: do we need a microscope or a telescope?" European Journal of Heart Failure 22, no. 10 (September 20, 2020): 1930–32. http://dx.doi.org/10.1002/ejhf.1995.

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Journal articles on the topic 'Telescopic failure'

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