Journal articles on the topic 'Gaskets Testing'
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W. S., Widodo, R. Soenoko, M. A. Choiron, and A. A. Sonief. "Sealing performance analysis of composite gaskets made of silicone rubber filled with ramie natural fibers." Journal of Mechanical Engineering and Sciences 13, no. 4 (December 30, 2019): 6178–94. http://dx.doi.org/10.15282/jmes.13.4.2019.28.0484.
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Silicon rubber gaskets are commonly used in many industries for low pressure sealing conditions only. The research studies about the sealing performance improvement of a novel composite gasket made of the silicone rubber filled with ramie natural fibers in a bolted joint connection. In this research the sample of gasket consists of 4 different types of gasket i.e. a pure silicone rubber gasket and the silicone rubber composite gasket with 1, 2 and 3 layers of ramie fiber woven. The gaskets are tested using a water pressure testing equipment with a variation of internal fluid pressure and difference torques at 8 N.m, 12 N.m, 16 N.m and 20 N.m. The sealing performance is measured based on the maximum fluid pressure that can be hold by the gaskets before the fluid leaking occurred. The results show that the silicone rubber composite gaskets have better sealing performance comparing with the pure silicone rubber gaskets where the silicon rubber gaskets capable to hold the internal fluid pressure until around 5 times rather than pure silicon rubber gaskets (0.17 MPa comparing with 0.90 MPa). On the other hand the sealing performance of the composite gasket with 3 layers is almost 2 times better than the composite gasket with 1 layer and around 1.5 times better than the composite gasket with 2 layer of fiber woven.
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Chen, Jiayan, Zhenyu Zhang, Lu Wang, and Qiang Wang. "Evaluation of Gasket Surface Contact Stress Uniformity Based on Gray-Level Co-Occurrence Matrix." Applied Sciences 12, no. 21 (November 2, 2022): 11110. http://dx.doi.org/10.3390/app122111110.
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Due to the high demand for compression recovery tests of metal gaskets, it is difficult to provide and evaluate uniform stress on metal gaskets. To effectively evaluate the uniformity of surface stress on a metal gasket, we propose a method of evaluating gasket surface stress based on gray-level co-occurrence matrix theory. Angular second moment and entropy are selected as the main characteristic parameters, and the evaluation indexes (f1 and f2) are proposed. The analysis is based on finite element calculation under different parameters of a gasket test rig. The angular second moment and entropy curve of the stress distribution cloud map are drawn according to the result of finite element calculation. The results show that the method can evaluate the uniformity of stress distribution. The best parameters of the gasket testing rig are obtained by analyzing the uniformity evaluation index. The method can realize rapid comparison and accurate evaluation of the gasket surface stress.
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Wang, Min, Xianlei Fu, Zheyuan Jiang, Chi Che, Ningjun Jiang, and Yanjun Du. "Swelling Behavior and Flow Rates of a Novel Hydrophilic Gasket Used in Composite Geomembrane Vertical Cutoff Walls and Infrastructures Exposed to Contaminated Groundwater." Buildings 12, no. 12 (December 13, 2022): 2207. http://dx.doi.org/10.3390/buildings12122207.
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The swelling capacity of novel hydrophilic gaskets used in geomembrane cutoff walls and infrastructures is critical for decreasing the flow rates of contaminated groundwater. This study investigated the swelling behavior, relaxation characteristics, flow rates, and micro-morphology of a hydrophilic gasket with different testing liquids. The radial swelling tests were performed using a device modified from single-lever consolidation instrument. A flow rates model apparatus was manufactured and employed to measure the flow rates of the poor-sealing hydrophilic gasket. According to the test results, the swelling ratio of the hydrophilic gaskets soaked in the DIW were the highest, followed by the NaCl solution, the MSW landfill leachate, and the CaCl2 solution. Relaxation phenomena appeared in all the specimens regardless of the testing liquids. The flow rates of the specimens penetrated with DIW, NaCl, and CaCl2 decreased to a stable state, and then increased extremely slowly to stable values. Moreover, self-healing of the hydrophilic gasket was observed. The micro-morphology indicated that sodium polyacrylate (PAAS) with insufficient expansion could separate from the matrix under high multivalent ionic strength or loading pressure conditions. Therefore, it is critical to develop the modified hydrophilic gasket with resistance to contaminated groundwater for a better barrier performance for use in contaminated sites and infrastructures.
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Kunkel, G. M. "Shielding Effectiveness of EMI Gasketed Joints." Measurement and Control 24, no. 9 (November 1991): 282–85. http://dx.doi.org/10.1177/002029409102400903.
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EMI gaskets are used extensively by the electrical/electronic engineering community to assist in inhibiting the flow of radiated electromagnetic fields into and out of electronic equipment. Shielding effectiveness tests are used extensively by the manufacturers of EMI gaskets to grade their products. The assumption made by the design engineering community is that the shielding effectiveness as presented in the data is what they will receive in their equipment. This assumption is not true due to the errors associated with the shielding effectiveness testing of the gaskets where errors of as much as 80 dB (10 000 times) can be represented. The paper describes briefly the problems associated with the shielding effectiveness test methods currently used and provides a detailed method of calculating the shielding effectiveness of an EMI gasketed joint using transfer impedance test data.
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Jaszak, Przemysław, and Łukasz Walencki. "Testing of the gaskets at liquid nitrogen and ambient temperature." Open Engineering 8, no. 1 (October 26, 2018): 329–36. http://dx.doi.org/10.1515/eng-2018-0036.
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Abstract The paper presents the results of the leakage measurements of bolted flanged joints operating at temperature of liquid nitrogen (77K) and ambient temperature. Three types of static gasket were tested. The results were presented in the form of a helium leakage rate as a function of its pressure. The measured data was discussed and compared with the leakage results obtained at the ambient temperature.
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Kobayashi, Takashi, Ryosuke Nogi, Koji Sato, and Syugo Goto. "Consideration of test methods for testing sealing behavior of gaskets." Proceedings of Yamanashi District Conference 2018 (2018): YC2018–082. http://dx.doi.org/10.1299/jsmeyamanashi.2018.yc2018-082.
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Walczak, R., J. Pawlicki, and A. Zagórski. "Tightness and Material Aspects of Bolted Flange Connections With Gaskets of Nonlinear Properties Exposed to Variable Loads." Archives of Metallurgy and Materials 61, no. 3 (September 1, 2016): 1409–16. http://dx.doi.org/10.1515/amm-2016-0231.
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Abstract The paper presents the problems regarding bolted flange connections with gaskets used in chemical, petrochemical and energy industry. The aim of the research is to present state of knowledge regarding pipelines and apparatus in industrial installations and rules and regulations regarding flange connections tightness. Additionally a calculation example regarding flange connection according to ASME VIII DIV 1 requirement and then detailed Finite Element Analysis presented; impact of nonlinear material properties (gasket loading unloading curves) on the connection tightness for complex loading programme is shown. It is finally concluded that in addition to usual design calculations more precise calculation is needed to fully verify behaviour of sealed connection at complex extreme variable loadings. Material aspect is very important at designing, testing, service and maintenance; taking it into consideration may avoid many problems related to safe exploitation.
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Hosseini, Payam, Sultan Alhomair, Zahra Faeli, Mohammad Pour-Ghaz, Mohammed Gabr, Detlef Knappe, and Cyrus Parker. "Degradation Model for the Tensile Strength of PVC and Rubber Gasket Materials Exposed to Benzene and PCE-Saturated Aqueous Solutions." Transportation Research Record: Journal of the Transportation Research Board 2674, no. 2 (February 2020): 274–83. http://dx.doi.org/10.1177/0361198120906126.
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In this paper, a tensile strength degradation model is developed for polyvinyl chloride (PVC) pipe and three rubber gasket materials commonly used in stormwater drains and wet utilities; the degradation model considers exposure to a single contaminant at its saturation level. The contaminant considered included benzene and tetrachloroethylene (PCE) because of their prevalence. The materials considered are unplasticized Polyvinyl chloride (u-PVC) utilized as the pipe material, and three types of rubber gaskets: Polychloroprene (Neoprene-CR), Acrylonitrile (nitrile) butadiene rubber (Buna-N), and fluoroelastomer rubber (FKM—Grade A VitonTM). First, the degradation rates of these materials are experimentally quantified using accelerated testing; then using the experimental results and Williams–Landel–Ferry (WLF) method a degradation model is developed. Finally, a simplified method is introduced to relate the tensile strength degradation of PVC to the penetration rate of the contaminants.
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Noda, Nao-Aki, Masato Nagawa, Fumitaka Shiraishi, and Akifumi Inoue. "Sealing Performance of New Gasketless Flange." Journal of Pressure Vessel Technology 124, no. 2 (May 1, 2002): 239–46. http://dx.doi.org/10.1115/1.1464876.
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This paper deals with a new seal system between two flanges without using gaskets. The system includes a groove and an annular lip that is held by one of the flange with its highest point in contact with the other flange to form a seal line when the flanges are assembled. The condition whether the system leaks or not depends on the shape and dimension of the annular lip and its deformation during the contact. In this study, several gasketless flanges are prepared with different lip dimensions to investigate the contact and sealing condition through an experimental and FEM analyses. The analyses indicate that the conditions can be expressed in terms of the maximum contact stress and the plastic zone size when the flanges are assembled. The helium leak testing reveals that the gasketless flange has better sealing performance compared to conventional gaskets.
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Rosentel, William, and Peter Holst. "Case study: Compilation of doorwall designs for speech privacy." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 264, no. 1 (June 24, 2022): 538–45. http://dx.doi.org/10.3397/nc-2022-769.
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A common complaint in offices is meetings within enclosed rooms disrupting nearby open workstations or poor speech privacy to circulation corridors. In this scenario, occupant satisfaction depends on multiple factors, including sound isolation of the wall, door, glazing, and the background noise levels. Using experience from several projects with collected measurement data, this presentation will review various door-wall design scenarios with post-construction testing results and conditions where day-two improvements were implemented to meet client standards. The limiting factor in sound isolation performance is often the door gaskets. Aluminum frames are commonly manufactured with integrated gaskets, which can be a cost-effective contractor replacement. However, these gaskets tend to be smaller than the typical recommended perimeter types and have been observed to form inconsistent seals once doors are installed. Floor transition strips for dropping bottom seals are another frequent coordination issue. Outside the enclosed room, coordination of the mechanical design and architectural ceiling choice should be used to define the appropriate corridor partition design to achieve acceptable outcomes. Where client standards and performance rating systems such as LEED and WELL define sound isolation criteria for corridor walls, a well-coordinated acoustical design is critical for achieving the credit objectives.
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Biedermann, Maurus, Katell Fiselier, and Koni Grob. "Testing migration from the PVC gaskets in metal closures into oily foods." Trends in Food Science & Technology 19, no. 3 (March 2008): 145–55. http://dx.doi.org/10.1016/j.tifs.2007.08.008.
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Gil, P., J. Fernandes, M. M. Neves, and Luís G. Reis. "Suitability of Corkrubber Gaskets in Gasoline-Ethanol Blends." Materials Science Forum 636-637 (January 2010): 266–72. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.266.
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The increasing use of biofuels, namely blends of gasoline with ethanol, requires the identification of its impact on the fuel admission components of internal combustion engines that have not been specially design to work with high levels of ethanol. This paper provides a discussion on performance testing of corkrubber gaskets from a commercial company (ACC – Amorim Cork Composites) to seal these engines using gasoline and gasoline-ethanol blends. In order to evaluate the chemical compatibility of four corkrubber composites, several samples were immersed in different blends of gasoline with ethanol to determine the changes of hardness, volume, thickness and weight. The results of these tests differed between materials, but all of them showed less damage tolerance to blends with low and medium percentages of ethanol (e.g., E5, E10, E25, E50) when compared to gasoline or blends with higher percentages of ethanol (E85).An aggressiveness factor is proposed to compile results from the immersion tests. Validation tests were carried out in conditions as close as possible to the service and accordingly to similar test standards. This study allows concluding on which of these corkrubber composites have adequate sealing properties for gasoline as well as blends of gasoline with ethanol.
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Staf, Marek, Daniel Tenkrát, and Tomáš Hlinčík. "Apparatus for testing He leakage through flange gaskets at elevated pressure and temperature." Progress in Nuclear Energy 139 (September 2021): 103831. http://dx.doi.org/10.1016/j.pnucene.2021.103831.
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Nasrullah, Hamid, Bahtiar Wilantara, and Sulitia Aji Tri Budi Utomo. "Reconditioning and Testing of the 1984 Toyota Rino Diesel Engine." Jurnal E-Komtek (Elektro-Komputer-Teknik) 6, no. 2 (December 31, 2022): 322–26. http://dx.doi.org/10.37339/e-komtek.v6i2.1074.
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The purpose of this research is to get a clear picture of the process of reconditioning and testing the 1984 Toyota Rino diesel engine. And to find out which components must be renovated for excellent engine performance. This research was conducted at the Piksi Ganesha Polytechnic Laboratory of Indonesia. The research method used is qualitative. The result of the reconditioning process is that several diesel engine components must be replaced in gaskets, air, and fuel filters. The results of testing the diesel engine Toyota Rino 1984 are: 1) Injector test, all injectors’ functions should run when tested using a pressure nozzle test; namely, the manometer shows 3000 psi when the lever is pressed, the nozzle can spray fuel tightly, and the nozzle does not leak; 2) Compression test, all cylinders are still in good condition when tested using a cylinder pressure tester, namely the manometer shows the number 30 kg/cm2.
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Hanušová, Kristýna, Aleš Rajchl, Lenka Votavová, Jaroslav Dobiáš, and Ingrid Steiner. "Testing the influence of various conditions on the migration of epoxidised soybean oil from polyvinylchloride gaskets." Food Additives & Contaminants: Part A 30, no. 11 (November 2013): 1963–75. http://dx.doi.org/10.1080/19440049.2013.825818.
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MOSTELLER, T. M., and J. R. BISHOP. "Sanitizer Efficacy Against Attached Bacteria in a Milk Biofilm." Journal of Food Protection 56, no. 1 (January 1, 1993): 34–41. http://dx.doi.org/10.4315/0362-028x-56.1.34.
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Pseudomonas fluorescens, Yersinia enterocolitica, and Listeria monocytogenes were shown to readily attach to both rubber and Teflon® surfaces. Sanitizer efficacy testing done in the laboratory with nonadherent bacteria could lead to false assumptions as to the sanitizer's true effectiveness under processing conditions where cells may be attached. The objectives in this study were: (a) evaluate the efficacy of in-use concentrations of sanitizers on bacteria attached to gasket materials, (b) compare bacterial attachment to rubber and Teflon® gaskets, (c) examine different methods of enumeration, and (d) compare sanitizer efficacy on attached and suspended bacteria. The goal reduction for all of the sanitizers tested was ≥3 log cycles or 99.9%. Results indicated that iodophor, hypochlorite, acid anionic, peroxyacetic acid, fatty acid, and quaternary ammonium sanitizers failed to provide an adequate reduction in the numbers of attached bacteria at levels of 104 to 105/mm2 in most cases. The test organisms attached in slightly higher numbers to the rubber surface versus Teflon®. Plate counts, impedance microbiology, and the direct epifluorescent filter technique were tested as methods of enumeration. Impedance microbiology was the best method of enumeration, since it allowed the estimation of both reversibly and irreversibly attached bacteria. The efficacy of sanitizers versus a bacterial suspensions resulted in a ≥ 5 log-cycle reduction. The same concentrations were relatively ineffective against the attached bacteria. The goal reduction was reached on the Teflon® surface with the iodophor, hypochlorite, and fatty acid sanitizers with a log-cycle reduction in the number of Yersinia enterocolitica of 3.09, 3.19, and 3.31, respectively. Pseudomonas fluorescens was reduced by 3.16 on both the rubber and Teflon® surfaces when exposed to the hypochlorite sanitizer.
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Pang, Shumeng, Weijun Tao, Yingjing Liang, Shi Huan, Yijie Liu, and Jiangping Chen. "Development of a True-Biaxial Split Hopkinson Pressure Bar Device and Its Application." Materials 14, no. 23 (November 29, 2021): 7298. http://dx.doi.org/10.3390/ma14237298.
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Although highly desirable, the experimental technology of the dynamic mechanical properties of materials under multiaxial impact loading is rarely explored. In this study, a true-biaxial split Hopkinson pressure bar device is developed to achieve the biaxial synchronous impact loading of a specimen. A symmetrical wedge-shaped, dual-wave bar is designed to decompose a single stress wave into two independent and symmetric stress waves that eventually form an orthogonal system and load the specimen synchronously. Furthermore, a combination of ground gaskets and lubricant is employed to eliminate the shear stress wave and separate the coupling of the shear and axial stress waves propagating in bars. Some confirmatory and applied tests are carried out, and the results show not only the feasibility of this modified device but also the dynamic mechanical characteristics of specimens under biaxial impact loading. This novel technique is readily implementable and also has good application potential in material mechanics testing.
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Yasinee, Wuttison, Thongyai Supakanok, Wacharawichanant Sirirat, and Piyasan Praserthdam. "Study on the Properties of Blends between Acrylonitrile-Butadiene Rubber and Acrylonitrile-Butadiene-Styrene or Poly(Styrene-co-Acrylonitrile)." Advanced Materials Research 812 (September 2013): 192–97. http://dx.doi.org/10.4028/www.scientific.net/amr.812.192.
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Acrylonitrile-butadiene rubber (NBR) or nitrile rubber is an unsaturated copolymer of butadiene and acrylonitrile. NBR has been widely used for fuel hoses, seals and gaskets due to its excellent oil and fuel resistance. Aiming to develop NBR which has resistance to oxygenated solvent, NBR with acrylonitrile content of 34 wt%, was blended with Acrylonitrile-butadiene-styrene (ABS) and Poly (Styrene-co-Acrylonitrile) (SAN) as binary polymer systems. The NBR/ABS and SAN blends were prepared by mechanical blending in the composition of 80/20, 70/30 and 60/40 w/w. The effects of ABS or SAN content on mechanical, morphological and thermal properties were investigated and compared with commercials NBR. Mechanical properties were determined using the tensile testing machine. The morphologies of polymer blends were investigated using scanning electron microscope (SEM). The thermal properties were examined using differential scanning calorimeter (DSC), thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). It has been found that percent compatibility of ABS and SAN into NBR rich phase are 2.69 and 1.53 wt% respectively.
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Fankhauser-Noti, Anja, and Koni Grob. "Migration of plasticizers from PVC gaskets of lids for glass jars into oily foods: Amount of gasket material in food contact, proportion of plasticizer migrating into food and compliance testing by simulation." Trends in Food Science & Technology 17, no. 3 (March 2006): 105–12. http://dx.doi.org/10.1016/j.tifs.2005.10.013.
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Donaldson, Keith W., and Akihiro Kajiyama. "Operationally Ready Advancements in Oil Free Corrosion Control for Advanced Materials." Key Engineering Materials 843 (May 2020): 153–58. http://dx.doi.org/10.4028/www.scientific.net/kem.843.153.
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Operationally ready is a key component to effective management of equipment, spares and systems through manufacturing, shipment and transport, meaning that products are impacted by how they stored, shipped and staged. That means no rust, no degradation and the ability to utilize the equipment or parts quickly, with no cleaning or additional work required. Significant advancements have been made in oil free, volatile free anti-corrosion protection to aid this. These advancements are in the form of plastics, laminates, canvas, woven products and shrink films that can be used to provide long term stable packaging that can be used both as short term, one-time use, multiple use applications or even used to create portable storage shelters. These materials will also help stabilize and help protect metals as well as non-metallic components and materials such as items that can swell, gaskets, fabric and rubber components, against degradation – this is critical since many systems are combination of materials, no longer just single material construction. These developments in oil free, volatile free packaging have been successfully incorporated into automotive applications with short term and long-term protection being available from the same packaging. Additionally, information on accelerated testing on already environmentally stressed items will be reviewed and solutions presented to their protection schemes as well.
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Zarzour, Mark, and John Vance. "Experimental Evaluation of a Metal Mesh Bearing Damper." Journal of Engineering for Gas Turbines and Power 122, no. 2 (January 3, 2000): 326–29. http://dx.doi.org/10.1115/1.483214.
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Metal mesh is a commercially available material used in many applications including seals, heat shields, filters, gaskets, aircraft engine mounts, and vibration absorbers. This material has been tested by the authors as a bearing damper in a rotordynamic test rig. The test facility was originally used to support the design of a turboprop engine, developing squirrel cages and squeeze film dampers for both the gas generator and power turbine rotors. To design the metal mesh damper, static stiffness and dynamic rap test measurements were first made on metal mesh samples in a specially designed nonrotating test fixture. These property tests were performed on samples of various densities and press fits. One sample was also tested in an Instron machine as an ancillary and redundant way to determine the stiffness. Using the stiffness test results and equations derived by a previous investigator, a spreadsheet program was written and used to size metal mesh donuts that have the radial stiffness value required to replace the squirrel cage in the power turbine. The squirrel cage and squeeze film bearing damper developed for the power turbine rotor was then replaced by a metal mesh donut sized by the computer code. Coast down tests were conducted through the first critical speed of the power turbine. The results of the metal mesh tests are compared with those obtained from previous testing with the squeeze film damper and show that the metal mesh damper has the same damping as the squeeze film at room temperature but does not lose its damping at elevated temperatures up to 103°C. Experiments were run under several different conditions, including balanced rotor, unbalanced rotor, heated metal mesh, and wet (with oil) metal mesh. The creep, or sag, of the metal mesh supporting the rotor weight was also measured over a period of several weeks and found to be very small. Based on these tests, metal mesh dampers appear to be a viable and attractive substitute for squeeze film dampers in gas turbine engines. The advantages shown by these tests include less variation of damping with temperature, ability to handle large rotor unbalance, and the ability (if required) to operate effectively in an oil free environment. Additional testing is required to determine the endurance properties, the effect of high impact or maneuver loads, and the ability to sustain blade loss loads (which squeeze films cannot handle). [S0742-4795(00)01002-4]
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Galikhanov, M. F., D. M. Akhmedzyanova, and N. R. Nikitin. "The Development and the Study of the Properties of Hydrosorption Material Based on a Blended Thermoplastic Vulcanisate." International Polymer Science and Technology 44, no. 8 (August 2017): 9–14. http://dx.doi.org/10.1177/0307174x1704400802.
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Hydrosorption thermoplastic vulcanisates (TPVs) with a controllable swelling rate have been developed. They contain low-density polyethylene (LDPE), nitrile butadiene rubber (NBR), and sodium carboxymethyl cellulose (Na-CMC) – a water-soluble polymer (WSP). They were mixed on a laboratory mill in two stages and vulcanised at a temperature of 170°C. At the first stage, the NBR with a vulcanising system and carbon black were mixed with the WSP at 50°C, and at the second stage this composite was mixed with the polyethylene (PE) at 140°C. The hydrosorption, deformation and strength, and electret properties of the obtained TPVs were studied. The study of the sorption properties under conditions of limited and unlimited access of water showed that composites consisting of 25% polyethylene and 75% WSP swell in water by ∼28%, and here processes of migration of the WSP out of the composites are absent. The deformation and strength properties were determined on an Inspekt Mini TR-3 kN tensile testing machine. The level of deformation and strength characteristics of the obtained TPVs is not high, which is due to the low adhesion between the PE and the polar NBR, and also between the NBR and the WSP. However, for seals and gaskets, the achievable level of strength properties is quite adequate. An electret state of the TPVs was obtained in a negative corona discharge as they cooled down after heating to 90°C. Washers were manufactured from the developed TPVs, and they were tested for their sealing capacity. It was shown that the electret state inhibits the process of swelling of the TPVs in water, which is due to the negative effect of the electric field on the rate at which wetting, dissolution, and diffusion processes take place. However, during service, the electret state of articles manufactured from the developed TPVs rapidly relaxes, after which the swelling process occurs at a steady rate. This makes it possible to carry out assembly work involving the fitting or replacement of seals made of the hydrosorption TPVs.
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Hansen, Brandon, Cody Coleman, Yi Zhang, and Maria Seale. "Text Classification and Tagging of United States Army Ground Vehicle Fault Descriptions in Support of Data-Driven Prognostics." Annual Conference of the PHM Society 12, no. 1 (November 3, 2020): 8. http://dx.doi.org/10.36001/phmconf.2020.v12i1.1154.
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The manner in which a prognostics problem is framed is critical for enabling its solution by the proper method. Recently, data-driven prognostics techniques have demonstrated enormous potential when used alone, or as part of a hybrid solution in conjunction with physics-based models. Historical maintenance data constitutes a critical element for the use of a data-driven approach to prognostics, such as supervised machine learning. The historical data is used to create training and testing data sets to develop the machine learning model. Categorical classes for prediction are required for machine learning methods; however, faults of interest in US Army Ground Vehicle Maintenance Records appear as natural language text descriptions rather than a finite set of discrete labels.
Transforming linguistically complex data into a set of prognostics classes is necessary for utilizing supervised machine learning approaches for prognostics. Manually labeling fault description instances is effective, but extremely time-consuming; thus, an automated approach to labelling is preferred. The approach described in this paper examines key aspects of the fault text relevant to enabling automatic labeling. A method was developed based on the hypothesis that a given fault description could be generalized into a category. This method uses various natural language processing (NLP) techniques and a priori knowledge of ground vehicle faults to assign classes to the maintenance fault descriptions.
The core component of the method used in this paper is a Word2Vec word-embedding model. Word embeddings are used in conjunction with a token-oriented rule-based data structure for document classification. This methodology tags text with user-provided classes using a corpus of similar text fields as its training set. With classes of faults reliably assigned to a given description, supervised machine learning with these classes can be applied using related maintenance information that preceded the fault.
This method was developed for labeling US Army Ground Vehicle Maintenance Records, but is general enough to be applied to any natural language data sets accompanied with a priori knowledge of its contents for consistent labeling. In addition to applications in machine learning, generated labels are also conducive to general summarization and case-by-case analysis of faults. The maintenance components of interest for this current application are alternators and gaskets, with future development directed towards determining the RUL of these components based on the labeled data.
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Leader, Jared O., Mark R. Walluk, Michael G. Waller, and Thomas A. Trabold. "Optimizing The Hot-Press Procedure Of High-Temperature Proton Exchange Membrane Fuel Cells For Adhesion Strength And Conductivity." ECS Meeting Abstracts MA2022-01, no. 37 (July 7, 2022): 1644. http://dx.doi.org/10.1149/ma2022-01371644mtgabs.
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As society considers alternatives to energy systems based on fossil fuel combustion, high-temperature proton exchange membrane (HT-PEM) fuel cells may play an important role in our future energy and transportation portfolio. When compared to low-temperature proton exchange membrane (LT-PEM) fuel cells, HT-PEM technology offers enhanced electrode kinetics, simplified water management, and most notably increased tolerance to fuel impurities such as carbon monoxide. However, compared to more conventional LT-PEM systems, less is known about the durability, performance, and fabrication of HT-PEM materials. Comprised of multiple layers, the membrane electrode assembly (MEA) is a fuel cell’s central component. In a fabrication process similar to LT-PEM MEAs, the proton-conducting membrane, electrodes, gas diffusion layers and sub gaskets are usually hot-pressed together. The parameters surrounding the hot-pressing operation can have a significant impact on the ultimate performance of the fuel cell, in addition to influencing process reliability and repeatability. In the current research, measurements of MEA thickness, impedance, and adhesion strength were obtained for samples over a range of conditions to optimize for the most suitable processing parameters. Testing in this study quantified the effects of hot-press time, temperature and pressure, within ranges of 1-10 minutes, 140 – 200oC, and 7.72 – 92.67 MPa (1120 - 13440 psi), respectively. After hot pressing, the MEA samples were tested for resistance with a 1260a Solartron impedance gain phase analyzer in tandem with a Solartron Ametek 12962a sample holder, and with a Scott internal bond tester for adhesion strength. Based on the results of these tests the optimal hot-press parameters were established, four 25 cm2 MEA were built and tested for performance with post-mortem analysis conducted utilizing scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). These measurements enabled interrogation of potential sources of conductivity loss associated with material layer delamination and/or dehydration of phosphoric acid in the polybenzimidazole (PBI) membrane. In this case, all tests were conducted at 140oC and the resulting material assembly was allowed to cool to room temperature in a nitrogen glove box prior to executing conductivity measurements (i.e., inverse of resistance). Our results have demonstrated that the optimal conditions for MEA hot-pressing for the HT-PEM system are around 170oC and 23.1 MPa for 5 minutes. Each curve in Figure 1 represents the performance of in-house MEAs, prepared using the optimized hot-pressing condition, with variation of platinum-on-carbon content (Pt/C) and total Pt loading. The data presented in Figure 1 demonstrate the effect of varying electrode thickness on MEA performance. Figure 1
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Yamazaki, N., Y. Taniguchi, and O. Kaburaki. "Testing the Central Engines in AGNs." Symposium - International Astronomical Union 188 (1998): 453–54. http://dx.doi.org/10.1017/s0074180900115992.
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It is very important to estimate the relationship between the central blackhole mass MBH and bolometric luminosity Lbol of AGNs, because such a relation may be useful to judge the validity of various models for AGNs (Koratkar & Gaskell 1991, hereafter KG91). The predictions of various models are summerized in Table 1, where B is the magnetic field around the central object.
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Liu, Ying Chun, and Yun Zuo. "Structural Failure Analysis of Shaft of Wobbly and Attrited Testing Equipment." Applied Mechanics and Materials 224 (November 2012): 105–8. http://dx.doi.org/10.4028/www.scientific.net/amm.224.105.
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In order to research the fatigue strength of gasket which is with new composite material in one plane, we designed and manufactured special testing equipment. The material of shaft of testing equipment is 30CrMnSi. In the experiment, the 30CrMnSi shaft was broken into two parts by suddenly. By structural analysis, static analysis and heat treatment analysis for shaft, we get the reason of fracture for shaft finally. The problem solved make the test goes well and can help design and manufacture testing equipment in the future.
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Abid, M. "Performance testing of gasketed flange joint under combined loading." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 223, no. 2 (December 11, 2008): 91–95. http://dx.doi.org/10.1243/09544089jpme221.
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This technical note presents joint strength and sealing capability of a gasketed flange joint using extensive experimental studies with different load combinations. Actual joint load capacity is determined under both the design and proof test pressure with maximum additional external loading (axial and bending) that can be applied for safe joint performance. In addition, application of combined load is also discussed in the light of equivalent pressure approach.
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Weng, Fang-Bor, Ay Su, Yur-Tsai Lin, Guo-Bin Jung, and Yen-Ming Chen. "Novel Testing Method for Fuel Cell Hardware Design and Assembly." Journal of Fuel Cell Science and Technology 2, no. 3 (January 31, 2005): 197–201. http://dx.doi.org/10.1115/1.1928929.
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A simple, low-cost testing method is proposed for fuel cell hardware development. A perforated aluminum foil with an array of small holes covered with carbon paper or cloth replaces the membrane electrode assemblies to test the contact resistance and gas permeability of the carbon paper. Practical fuel cells of 50cm2 reaction area with different gasket thicknesses and compressed pressures are tested for performance. The results of ohmic resistance and permeability of compressed carbon paper indicate strong relevance to cell performance, demonstrating that this novel testing method is valuable for fuel cell hardware development. Also, the compression mechanism of the diffusion layer is discussed along with a proposal for a strategy for improving cell performance. After that, an advanced design of a 25cm2 single cell is developed. The results of cell performance of the advanced cell are acceptable and competitive with the performance data of commercial products.
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Gilani, Amir S., Andrew S. Whittaker, and Gregory L. Fenves. "Seismic Evaluation and Retrofit of 230-kV Porcelain Transformer Bushings." Earthquake Spectra 17, no. 4 (November 2001): 597–616. http://dx.doi.org/10.1193/1.1427316.
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Static and earthquake-simulator testing of two 230-kV, 3000A, Type-U transformer bushings manufactured in the mid 1980s by the General Electric (GE) Company was undertaken to evaluate both the seismic performance of bushings known to be vulnerable to damage from moderate earthquake shaking, and the efficacy of simple retrofit details. Both bushings survived earthquake shaking compatible with the IEEE spectrum for High Level qualification when mounted on a rigid frame. When mounted on a flexible frame, one 230-kV bushing was unable to sustain the High Level qualification shaking without oil leakage and slip of the porcelain units. Two retrofit details utilizing two semicircular ring plates and epoxy filler were prepared by utility representatives with the objective of limiting slip of the UPPER-1 porcelain unit over the gasket connection. The second detail, Ring-2, permitted the 230-kV bushing to sustain substantially larger accelerations and displacements than those of the unretrofitted bushing and eliminated the permanent slip of the UPPER-1 porcelain unit over the gasket connection for extreme earthquake shaking.
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TARASOV, V. V., I. V. ZAGVOZDKIN, and P. V. NIKOLAEV. "EXPERIENCE AT THE APPLICATION OF WATERPROOFING DEVICES COMBINED TYPE IN THE SHAFTS OF POTASH MINES." News of the Tula state university. Sciences of Earth 3, no. 1 (2020): 188–201. http://dx.doi.org/10.46689/2218-5194-2020-3-1-188-201.
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The article presents a world experience in the application of waterproofing devices combined type in the mine shafts of potash and salt mines. A possibility of applying a chemical sealing ring together with wooden water seal has been considered. The article presents testing of physical properties of the chemical sealing ring material designed for sealing the support of the mine shafts of potash mines. The article shows an efficiency of the chemical sealing ring which suggests its use as an additional waterproof gasket together with wooden water seal.
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Gao, Yin Han, Meng Si, Peng Cheng, and Jun Cheng Chi. "Design of Electronic Control System for HCCI Optical Engine and Optical Testing." Applied Mechanics and Materials 721 (December 2014): 639–42. http://dx.doi.org/10.4028/www.scientific.net/amm.721.639.
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An optical engine system have been designed which can realize the goal of spark ignition and homogeneous charge compression ignition. This system consists of an optical engine and an electric control system. We have measured temperature in cylinder and molar coefficient of the main material (CO2, O2, N2, H2O, fuel) which has a resolution of nanosecond level and millimeter level. To realize the visualization in cylinder, extended pistons, extended cylinder liner and extended cylinder body have been designed and all of them have optical window. To realize the path of laser, a ring gasket of the laser window has been added between the original cylinder head and the extended cylinder body. An optical engine electronic control system based on SCM 80C196 has been designed to make the optical engine work in different testing strategies. The experimental results show the optical engine work well under the control of electric control system and we can detect optical Raman spectroscopy in the optical engine.
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Zhang, Han, Yue Li, and Ya Shun Wang. "An Identification Method of Failure Mechanism Consistency for Rubber Materials in Accelerated Aging Testing." Key Engineering Materials 723 (December 2016): 237–41. http://dx.doi.org/10.4028/www.scientific.net/kem.723.237.
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The failure mechanism of rubber materials under accelerated stress in aging process may be different from that under normal conditions. Therefore, identification of the failure mechanism consistency is necessary for the accelerated aging testing of rubber material. To solve the problem, we study the relationship between the aging velocity of permanent compression set value and aging time. Firstly, according to the relationship, the aging velocity constant is obtained through the least square method. Then, combining with the aging velocity constant, we found that the activation energy is equal to the slope of linear function about Arrhenius model. Based on that failure activation energy keeps same under same failure mechanism, an identification method about failure mechanism consistency is developed. Finally, to demonstrate and validate the proposed method, we take the accelerated aging testing for the nitrile rubber-26 sealing gasket as an example.
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Cheon, Kang-Min, Ugochukwu Ejike Akpudo, Akeem Bayo Kareem, Okwuosa Chibuzo Nwabufo, Hyeong-Ryeol Jeon, and Jang-Wook Hur. "An FEA-Assisted Decision-Making Framework for PEMFC Gasket Material Selection." Energies 15, no. 7 (April 1, 2022): 2580. http://dx.doi.org/10.3390/en15072580.
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Recent research studies on industrial cyber-physical systems (ICPSs) have witnessed vast patronage with emphasis on data utility for improved design, maintenance, and high-level decision making. The design of proton-exchange membrane fuel cells (PEMFC) is geared towards improving performance and extending life cycles. More often, material selection of PEMFC components contributes a major determining factor for efficiency and durability with the seal/gasket quality being one of the most critical components. Finite element analysis (FEA) offers a simulated alternative to real-life stress analysis of components and has been employed on different rubber-like gasket materials for hydrogen fuel cells for determining an optimal strain energy density function using different hyperelastic models following uniaxial tensile testing. The results show that the Mooney–Rivlin, Ogden, and Yeoh models were the most fitting model with the best stress–strain fit following a weighted error evaluation criteria which returned 18.54%, 19.31%, and 21.96% for 25% displacement, and 22.1%, 21.7%, and 21.17% for 40% displacements, respectively. Further empirical analysis using the multi-metric regression technique for compatibility testing (curve similarity) between the hyperelastic model outputs and the tensile data reveal that the Yeoh model is the most consistent as seen in the marginal error difference amidst increasing displacement while the Arruda–Boyce model is most inconsistent as shown in the high error margin as the displacement increases from 25% to 40%. Lastly, a comparative assessment between different rubber-like materials (RLM) was presented and is expected to contribute to improved decision-making and material selection.
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Bhargava, S., K. A. O'Leary, T. C. Jackson, and B. Lakshmanan. "DURABILITY TESTING OF SILICONE MATERIALS FOR PROTON EXCHANGE MEMBRANE FUEL CELL USE." Rubber Chemistry and Technology 86, no. 1 (March 1, 2013): 28–37. http://dx.doi.org/10.5254/rct.13.88931.
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ABSTRACT Silicone resins are ideal candidates for proton exchange membrane fuel cells (PEMFC) sealing and gasketing. They have many advantages for PEMFC application, such as superior stability and longevity under harsh environments, low water absorption, and broad temperature range. However, as this work shows, silicone-based materials have one big drawback: low molecular weight siloxanes, oligomers, and/or degradation byproducts may readily migrate from the base material into the fuel cell membrane, forming glassy structures, reducing the mechanical durability, and ultimately fracturing the proton exchange membrane (PEM). A novel, in situ testing method has been developed to test the effect of siloxanes on PEMFCs. The mechanism for migration of cyclic siloxanes to the PEM interface, causing it to fail in a brittle fashion, is presented. A commercially available silicone gasket material was used as a case study to validate the mechanism. Optical microscopy, scanning electron microscopy, and inductively coupled plasma were used to perform failure analysis of the tested samples. Thermogravimetric analysis was used to measure the removal rate of low molecular weight cyclic siloxanes. Gas chromatography–mass spectrometry was used to separate the organic molecules off-gassing from the material at temperature and provide a mass spectrum of each component.
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Abid, M., K. A. Khan, and J. A. Chattha. "PERFORMANCE TESTING OF A GASKETED BOLTED FLANGE PIPE JOINT UNDER COMBINED PRESSURE AND THERMAL LOADING." Experimental Techniques 35, no. 6 (October 7, 2010): 35–37. http://dx.doi.org/10.1111/j.1747-1567.2010.00667.x.
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Rakitin, Boris, and Ming Xu. "Centrifuge testing to simulate buried reinforced concrete pipe joints subjected to traffic loading." Canadian Geotechnical Journal 52, no. 11 (November 2015): 1762–74. http://dx.doi.org/10.1139/cgj-2014-0483.
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Pipeline water leakage has become a serious problem in many countries. It has been widely noted that most of the damage to the pipelines occurs in the joints where two pipes are connected to each other. This paper presents the results of a geotechnical centrifuge testing program in which the response of a 12 m long (in prototype scale) large-diameter reinforced concrete pipeline with gasketed bell-and-spigot joints subjected to three standard American Association of State Highway and Transportation Officials design load configurations has been investigated. The results show that most vertical pipe movements occurred during the first 10 cycles of traffic loading. Under design tandem loading, the pipe joint displacements were significantly higher than those under the other two traffic load configurations. An increase of soil cover depth resulted in a reduced influence of surface loading, the effect of which was the most significant for two single pairs of wheels of design trucks in passing mode. Furthermore, two pipes on the left side and two pipes on the right side from the tested joint were influenced significantly by the surface loading, while the pipeline movements were not symmetrical. Although the joint directly under the load experienced the largest rotation, the possibility of leakage in the second joint in the spigot-to-bell direction was also high, due to large differential displacement between the pipes.
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Elavarasi, C., and T. Shanmuganantham. "CPW-fed SGF-TSRR antenna for multiband applications." International Journal of Microwave and Wireless Technologies 9, no. 9 (June 19, 2017): 1871–76. http://dx.doi.org/10.1017/s1759078717000605.
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In this paper, a solid co-planar waveguide-fed fractal metamaterial antenna is offered. The proposed design consists of Sierpinski gasket iterations and a complementary triangular split ring resonator (CTSRR) loaded underneath the substrate, which is accountable for pull off multiband uniqueness and resolve good impedance identical. In sketch to hassle multiresonant frequency band facet, these CTSRR are entrenched reverse side of the substrate. The anticipated antenna with a dense dimension of 12 × 14 × 1.6 mm3 is fabricated and tested. The testing result designates that the projected design has −10 dB of 5.72, 14.3, and 16.06 GHz, respectively, and covers 5.72 GHz wireless local area network, 14.3 GHz fixed satellite, and 16.06 GHz International Telecommunication Union (ITU) band. It has fine emission uniqueness for jointly E-plane and H-plane in all the preferred occurrence bands and produce superior performance compared with the offered antenna intend in the prose. The loaded CTSRR construction recital is validated all the way during negative permeability pulling out and assorted parametric study.
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Hoofnagle, Andrew N., Thomas J. Laha, and Thomas F. Donaldson. "A rubber transfer gasket to improve the throughput of liquid–liquid extraction in 96-well plates: Application to vitamin D testing." Journal of Chromatography B 878, no. 19 (June 2010): 1639–42. http://dx.doi.org/10.1016/j.jchromb.2010.04.010.
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Najafi, Mohammad, Guillermo Ramirez, Richard Mielke, Brent Keil, Glenn Davidenko, Shah Rahman, and Abhay Jain. "Design, Analysis, and Full-Scale Testing of the Rolled Groove Gasket Joint System in AWWA C303 Bar-Wrapped, Steel-Cylinder Concrete Pressure Pipe." Journal of Pipeline Systems Engineering and Practice 4, no. 3 (August 2013): 156–69. http://dx.doi.org/10.1061/(asce)ps.1949-1204.0000133.
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Bazylev, V. V., P. A. Batrakov, D. M. Khadiev, A. A. Egorov, and N. A. Eremin. "Aortic root prosthesis with pericardial cusps "Russian conduit": A hydrodynamic experiment." Patologiya krovoobrashcheniya i kardiokhirurgiya 25, no. 4 (December 28, 2021): 97. http://dx.doi.org/10.21688/1681-3472-2021-4-97-105.
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<p><strong>Aim.</strong> The study aimed to compare the hydrodynamic characteristics and durability of the aortic root prosthesis with pericardial cusps with various options for the formation of commissures.</p><p><strong>Methods.</strong> Nine conduits with pericardial valves were formed according to the technique described by Ozaki. The prostheses were divided into 3 groups of 3 specimens each: group 1 — without additional reinforcing seams on the top of the commissure; group 2 — with an additional U-shaped seam without gasket; and group 3 — with an additional suture with an opposite pericardial gasket. The prostheses were fixed on a stand for hydrodynamic testing of artificial heart valves. The hydrodynamic characteristics of the prostheses were evaluated. The hydrodynamics of the frame biological prosthesis was used for comparison. After assessing the hydrodynamic parameters of the aortic root prostheses, their work durability was tested. Defects of the pericardial cusps were studied macroscopically.</p><p><strong>Results. </strong>Two samples from group 2 were withdrawn from testing ahead of schedule at around 11 × 10<sup>6</sup> cycles, which is approximately 3.5 months of normal heart function. The other prostheses remained competent and were removed for an examination at 32 × 10<sup>6</sup> cycles, which is approximately 9.6 months of normal heart function.</p><p><strong>Conclusion. </strong>The hydrodynamics of the aortic root prosthesis with pericardial valves was comparable to the hydrodynamics of the frame biological prosthesis. Additional U-shaped sutures in the commissure area of the pericardial cusps did not increase the functional durability of the aortic root prosthesis with pericardial leaflets and served as additional risk factors for leaflet perforation. Implantation of pericardial leaflets into a vascular graft resulted in a different distribution of dynamic stress compared to the original aortic valve neocuspidisation, which preserved the aortic root.</p><p>Received 8 July 2021. Revised 30 August 2021. Accepted 7 September 2021.</p><p><strong>Funding:</strong> The study did not have sponsorship.</p><p><strong>Conflict of interest:</strong> Authors declare no conflict of interest.</p><p><strong>Contribution of the authors<br /> </strong>Conception and study design: V.V. Bazylev, P.A. Batrakov<br /> Data collection and analysis: P.A. Batrakov, D.M. Khadiev, A.A. Egorov, N.A. Eremin<br /> Drafting the article: P.A. Batrakov<br /> Critical revision of the article: V.V. Bazylev, P.A. Batrakov<br /> Final approval of the version to be published: V.V. Bazylev, P.A. Batrakov, D.M. Khadiev, A.A. Egorov, N.A. Eremin<strong> </strong></p>
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Rooney, Alan D., Marjorie D. Cantine, Kristin D. Bergmann, Irene Gómez-Pérez, Badar Al Baloushi, Thomas H. Boag, James F. Busch, Erik A. Sperling, and Justin V. Strauss. "Calibrating the coevolution of Ediacaran life and environment." Proceedings of the National Academy of Sciences 117, no. 29 (July 6, 2020): 16824–30. http://dx.doi.org/10.1073/pnas.2002918117.
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The rise of animals occurred during an interval of Earth history that witnessed dynamic marine redox conditions, potentially rapid plate motions, and uniquely large perturbations to global biogeochemical cycles. The largest of these perturbations, the Shuram carbon isotope excursion, has been invoked as a driving mechanism for Ediacaran environmental change, possibly linked with evolutionary innovation or extinction. However, there are a number of controversies surrounding the Shuram, including its timing, duration, and role in the concomitant biological and biogeochemical upheavals. Here we present radioisotopic dates bracketing the Shuram on two separate paleocontinents; our results are consistent with a global and synchronous event between 574.0 ± 4.7 and 567.3 ± 3.0 Ma. These dates support the interpretation that the Shuram is a primary and synchronous event postdating the Gaskiers glaciation. In addition, our Re-Os ages suggest that the appearance of Ediacaran macrofossils in northwestern Canada is identical, within uncertainty, to similar macrofossils from the Conception Group of Newfoundland, highlighting the coeval appearance of macroscopic metazoans across two paleocontinents. Our temporal framework for the terminal Proterozoic is a critical step for testing hypotheses related to extreme carbon isotope excursions and their role in the evolution of complex life.
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Kukuh wibawa, Tatang. "ANALISIS KEBAKARAN TANGKI TIMBUN TIPE ALUMINIUM GEODESIC DOME ROOF." Journal of Forensic Expert 2, no. 1 (April 28, 2022): 38–57. http://dx.doi.org/10.54579/jfe.v2i1.21.
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ABSTRACT
A Storage tank at oil refinery caught fire on Saturday, November 13, 2021 at 20.00 Wib. The burnt tank with a capacity of about 31,000 kiloliters (kl) was fully filled, the impact caused by the fire was in the form of direct losses, damage to surrounding infrastructure and other losses. The research method is to examine the level of damage to the condition of the storage tank due to fire by examining the parts of the tank to determine the location of the first fire location. The second is to carry out a thorough inspection of data and technical information on the tank, operations and systems. The third is carrying out inspection and data analysis, technical information on the installed tank, testing and measuring in the tank. Then the four carry out an analysis of the fire process and conclude from the overall results of the inspection.The results of the fire/explosion was the ignition of Pertalite type hydrocarbon liquid vapor which had reached the flammable range and the explosion limit in the Northwest Part of the Aluminum Geodesic Dome Roof Tank by a lightning strike which could cause tear/melt on the Aluminum Geodesic Dome Roof and damage to the Seal (Seal Hub Cover Gusset and Batten Gasket Sturt) Tank and the inability of the bounding grounding system of the roof cover to the wall and GT (Ground Tank) 1-8 transferring lightning strike currents.
ABSTRAK
Sebuah tangki pada kilang minyak terbakar pada Sabtu, 13 November 2021 pukul 20.00 Wib. Tangki yang terbakar dengan kapasitas sekitar 31.000 kiloliter (kl) terisi penuh, dampak yang diakibatkan kebakaran berupa kerugian langsung, kerugian infrastruktur sekitar yang terdampak dan kerugian lainnya. Metode penelitian ini pertama melakukan pemeriksaan tingkat kerusakan kondisi tangki timbun akibat kebakaran dengan memeriksa bagian-bagian tangki untuk menentukan lokasi api pertama kebakaran. Kedua melaksanakan pemeriksaan data dan keterangan teknis menyeluruh terhadap tangki, operasional dan sistem nya. Ketiga melaksanakan pemeriksaan dan analisa data keterangan teknis terhadap tangki yang terpasang, pengujian dan pengukuran di tangki. Kemudian keempat melaksanakan analisa proses terjadinya kebakaran dan menyimpulkan dari keseluruhan hasil pemeriksaan. Hasil penelitian disimpulkan penyebab terjadinya kebakaran/ledakan adalah tersulutnya uap cairan hidrokarbon jenis Pertalite yang sudah mencapai batas mudah terbakar (flammable range) dan explosion limit di Bagian Barat Laut pada Aluminium Geodesic Dome Roof Tangki Timbun oleh sambaran petir yang dapat menyebabkan sobekan/pelelehan pada Aluminium Geodesic Dome Roof dan kerusakan pada Seal (Seal Hub Cover Gusset dan Batten Gasket Sturt) Tangki Timbun serta ketidakmampuan sistem bounding grounding tutup atap terhadap dinding GT (Ground Tank) 1-8 dalam mentransfer arus sambaran petir.
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Ishimaru, Hajime. "Developments and Applications for All-Aluminum Alloy Vacuum Systems." MRS Bulletin 15, no. 7 (July 1990): 23–31. http://dx.doi.org/10.1557/s0883769400059212.
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Aluminum and aluminum alloys have long been among the preferred materials for ultrahigh vacuum (UHV) systems operating in the 10−10–10−11 torr (10−8–10−11 Pa) range. Pure aluminum and aluminum alloys have an extremely low outgassing rate, are completely nonmagnetic, lack crystal structure transitions at low temperatures, are not sources of heavy metals contamination in semiconductor processing applications, have low residual radioactivity in radiation environments, and are lightweight. Because of aluminum's high thermal conductivity and low thermal emissivity, aluminum components can tolerate high heat fluxes in spite of the relatively low melting point of aluminum.Recently developed aluminum alloys and new surface finishing techniques allow the attainment of extremely high vacuums (XHV) in the 10−12–10−13 torr (10−10–10−11 Pa) range. XHV technology requires the use of special aluminum alloy flange/gasket/bolt, nut and washer combinations, aluminum alloy-ceramic seals, windows, bellows, right-angle and gate valves, turbomolecular pumps, sputter ion pumps and titanium sublimination pumps, Bayard-Alpert ion gauges, quadrupole mass filters, and related aluminum alloy vacuum components. New surface treatment methods and new techniques in welding and extremely sensitive helium leak testing are required. In short, a whole new technology has been developed to take advantage of the opportunities presented by these new vacuum materials. This article describes some of these newly developed fabrication technologies and vacuum materials.The TRISTAN electron-positron collider constructed at the National Laboratory for High Energy Physics in Japan is the first all-aluminum alloy accelerator, and the first to use UHV technology.
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Brown, R. G., G. M. Buchheim, D. A. Osage, and J. L. Janelle. "Fitness for Service Evaluation of Ring Joint Groove Cracking." Journal of Pressure Vessel Technology 122, no. 1 (October 29, 1999): 72–75. http://dx.doi.org/10.1115/1.556153.
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Cracking of ring joint style flanges has been a recurring problem in the petrochemical industry, particularly in high-pressure hydrogen processing vessels. The cracking of the ring joint groove region is an inherent problem with the design. The ring groove is subjected to high stresses from the wedging action of the gasket and the ring groove radii are not substantial enough to effectively reduce the stress concentrating effect. A fitness for service assessment was conducted for a hydrogen processing vessel containing cracks in the ring groove radius region of a ring joint style flange. The flange was forged 2-1/4Cr-1Mo material with a Type 347 SS overlay. Results of an elastic-plastic numerical fracture mechanics assessment showed that the driving force for crack propagation was high for a very localized region near the ring groove radius. However, the driving force decreased significantly for deeper cracks as the crack tip became removed from the very localized high stress region of the ring groove. The assessment also showed that the highest stresses occurred during the bolt-up operation. Metallurgical tests were performed on a small sample removed from the flange. The chemistry, grain size, microstructure, and hardness of the material indicated that the probability that this material had very low resistance to hydrogen-assisted crack growth during downtime was quite small and that the resistance to crack advance during service was good. Therefore, the combined results of the fracture assessment and metallurgical testing were used to justify continued operation without repair of the cracks present in the flange. [S0094-9930(00)01901-6]
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Weltschev, Margit, and Ralph Baessler. "Use of Alloy 59 for the Transport of Highly Corrosive Dangerous Goods." Advanced Materials Research 278 (July 2011): 581–86. http://dx.doi.org/10.4028/www.scientific.net/amr.278.581.
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Alloy 59 (NiCr23Mo16Al) with a lot of chromium, molybdenum and nickel possesses excellent resistance not only to reducing but also oxidizing chemicals. Both the Nickel alloy 59 and the superaustenitic steel alloy 31 have already been used as shell materials for tank vehicles or tank containers. Use of these alloys allows the transport of a signifi-cantly more wider variety of chemicals and, especially, waste mixtures than the use of common aus-tenitic steels. Another advantage is the extension of test intervals of for transport tanks. In Germany the “BAM-List – Requirements for Tanks for the Transport of Dangerous Goods” is the basis for substance-related prototype approvals for tank containers designed for the car¬ri¬age of dangerous goods issued by the Federal Institute for Materials Re¬search and Testing (BAM). Com-patibility evaluations of selected metallic material groups as well as polymeric gasket and lining materials under the influence of approximately 7000 dangerous goods and water-polluting sub-stances are published in the BAM-List. Alloy 59 belongs to the group of metallic materials in the BAM-List. Due to the large number of dangerous goods in the BAM-List BAM, IKS Dresden and ThyssenKrupp VDM performed a comprehensive corrosion test programme with welded specimens of the nickel alloy 59 and the superaustenitic steels alloy 926 and alloy 31 in the period 2002 - 2010. Especially In particular alloy 59 and alloy 31 were exposed to a large number of corrosive sub-stances such as various mixtures of both nitric acid/sulphuric acid and nitric acid/phosphoric acid at 55 °C. Other corrosive test substances were different organic and inorganic halogenides, peroxyace-tic acid and molten substances. In the case of molten chemicals such as monochloroacetic acid the test temperature was increased to more than 100 °C. The test results presented in this paper are al-ready included in the 10th edition of the BAM-List and, therefore, available to the customer.
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Грешта, Виктор Леонидович, Дмитрий Викторович Павленко, Ярослав Викторович Двирнык, and Дарья Владимировна Ткач. "РАСЧЕТНО-ЭКСПЕРИМЕНТАЛЬНАЯ МЕТОДИКА ОПРЕДЕЛЕНИЯ ДИНАМИЧЕСКОГО МОДУЛЯ УПРУГОСТИ ПРИРАБАТЫВАЕМЫХ УПЛОТНИТЕЛЬНЫХ ПОКРЫТИЙ ТУРБИН ГТД." Aerospace technic and technology, no. 8 (August 31, 2019): 105–13. http://dx.doi.org/10.32620/aktt.2019.8.16.
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The aim of the work was the development and testing of a method for determining the dynamic modulus of elasticity of running-in sealing gasket coatings for GTE turbines. Many contradictory requirements are put forward to these coatings, therefore, to satisfy them, it was proposed to apply coatings with variable properties at various stages of the life cycle of gas turbine engines. However, the development of new coatings requires a variety of mechanical tests, including to evaluate the dynamic modulus of elasticity. The porous structure and, accordingly, the low strength of the developed coatings do not allow the use of standard methods for the evaluation of mechanical properties, so there is a need to develop a special method for determining the elastic modulus. In the course of the study, the finite element method, statistical methods, experimental methods for determining the natural frequency of oscillations were applied. Investigations were carried out for running-in sealing coating of the stator of turbines of gas turbine engines KNA-82 + CoNiCrAlY. The numerical experiment was performed in the Ansys Work-bench 2019 R2 software package. Since coatings are used at elevated temperatures, it was necessary to estimate the modulus of elasticity at various temperatures, which required additional studies of temperature-dependent properties that affect the desired value. As a result of the implementation of the plan of a numerical experiment to determine the frequency of natural oscillations of samples with a coating while varying its elastic modulus and temperature, as well as solving the inverse problem of establishing the dependence of the dynamic elastic modulus on the natural oscillation frequency of a coated sample, we developed a calculation and experimental method for determining the dynamic modulus elasticity of running-in sealing coatings of GTE turbines. The developed technique is used to determine the dynamic modulus of elasticity of running-in coatings of different chemical composition and structure in the range of operating temperatures, which can be used to optimize their composition, structure, and properties.
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Hipp, H. S., A. J. Gaskins, Z. P. Nagy, S. M. Capelouto, D. B. Shapiro, and J. B. Spencer. "Effect of oocyte donor stimulation on recipient outcomes: data from a US national donor oocyte bank." Human Reproduction 35, no. 4 (March 6, 2020): 847–58. http://dx.doi.org/10.1093/humrep/deaa003.
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Abstract STUDY QUESTION How does ovarian stimulation in an oocyte donor affect the IVF cycle and obstetric outcomes in recipients? SUMMARY ANSWER Higher donor oocyte yields may affect the proportion of usable embryos but do not affect live birth delivery rate or obstetric outcomes in oocyte recipients. WHAT IS KNOWN ALREADY In autologous oocyte fresh IVF cycles, the highest live birth delivery rates occur when ~15–25 oocytes are retrieved, with a decline thereafter, perhaps due to the hormone milieu, with super-physiologic estrogen levels. There are scant data in donor oocyte cycles, wherein the oocyte environment is separated from the uterine environment. STUDY DESIGN, SIZE, DURATION This was a retrospective cohort study from 2008 to 2015 of 350 oocyte donors who underwent a total of 553 ovarian stimulations and oocyte retrievals. The oocytes were vitrified and then distributed to 989 recipients who had 1745 embryo transfers. The primary outcome was live birth delivery rate, defined as the number of deliveries that resulted in at least one live birth per embryo transfer cycle. PARTICIPANTS/MATERIALS, SETTING, METHODS The study included oocyte donors and recipients at a donor oocyte bank, in collaboration with an academic reproductive endocrinology division. Donors with polycystic ovary syndrome and recipients who used gestational carriers were excluded. The donors all underwent conventional ovarian stimulation using antagonist protocols. None of the embryos underwent pre-implantation genetic testing. The average (mean) number of embryos transferred to recipients was 1.4 (range 1–3). MAIN RESULTS AND THE ROLE OF CHANCE Per ovarian stimulation cycle, the median number of oocytes retrieved was 30 (range: 9–95). Among the 1745 embryo transfer cycles, 856 of the cycles resulted in a live birth (49.1%). There were no associations between donor oocyte yield and probability of live birth, adjusting for donor age, BMI, race/ethnicity and retrieval year. The results were similar when analyzing by mature oocytes. Although donors with more oocytes retrieved had a higher number of developed embryos overall, there was a relatively lower percentage of usable embryos per oocyte warmed following fertilization and culture. In our model for the average donor in the data set, holding all variables constant, for each additional five oocytes retrieved, there was a 4% (95% CI 1%, 7%) lower odds of fertilization and 5% (95% CI 2%, 7%) lower odds of having a usable embryo per oocyte warmed. There were no associations between donor oocyte yield and risk of preterm delivery (<37 weeks gestation) and low birthweight (<2500 g) among singleton infants. LIMITATIONS, REASONS FOR CAUTION Ovarian stimulation was exclusively performed in oocyte donors. This was a retrospective study design, and we were therefore unable to ensure proportional exposure groups. These findings may not generalizable to older or less healthy women who may be vitrifying oocytes for planned fertility delay. There remain significant risks to aggressive ovarian stimulation, including ovarian hyperstimulation. In addition, long-term health outcomes of extreme ovarian stimulation are lacking. Lastly, we did not collect progesterone levels and are unable to evaluate the impact of rising progesterone on outcomes. WIDER IMPLICATIONS OF THE FINDINGS Live birth delivery rates remain high with varying amounts of oocytes retrieved in this donor oocyte model. In a vitrified oocyte bank setting, where oocytes are typically sent as a limited number cohort, recipients are not affected by oocyte yields. STUDY FUNDING/COMPETING INTEREST(S) Additional REDCap grant support at Emory was provided through UL1 TR000424. Dr. Audrey Gaskins was supported in part by a career development award from the NIEHS (R00ES026648).
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"Testing gaskets for fire resistance." Sealing Technology 1996, no. 35 (November 1996): 4–5. http://dx.doi.org/10.1016/s1350-4789(96)90124-5.
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Aweimer, Ali Salah Omar, and Abdel-Hakim Bouzid. "Evaluation of Interfacial and Permeation Leaks in Gaskets and Compression Packing." Journal of Nuclear Engineering and Radiation Science 5, no. 1 (January 1, 2019). http://dx.doi.org/10.1115/1.4041691.
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The quantities of leak rate through sealing systems are subjected to strict regulations because of the global concern on radiative materials. The maximum tolerated leak is becoming a design criterion in pressure vessel design codes, and the leak rate for an application under specific conditions is required to be estimated with reasonable accuracy. In this respect, experimental and theoretical studies are conducted to characterize gasket and packing materials to predict leakage. The amount of the total leak is the summation of the permeation leak through the sealing material and the interfacial leak generated between the sealing element and its mating surfaces. Unfortunately, existing models used to predict leakage do not separate these two types of leaks. This paper deals with a study based on experimental testing that quantifies the amount of these two types of leaks in bolted gasketed joints and packed stuffing boxes. It shows the contribution of interfacial leak for low and high contact surface stresses and the influence of the surface finish of 0.8 and 6.3 μm (32 and 250 μin) resulting from phonographic grooves in the case of a bolted flange joint. The results indicate that most leakage is interfacial, reaching 99% at the low stress while interfacial leak is of the same order of magnitude of permeation leak at high stresses reaching 10−6 and 10−8 mg/s in both packing and gaskets, respectively. Finally, particular focus is put on the technique of precompression to improve material sealing tightness.
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Xianjun, Zhou, Chen Chunlei, Li Jianhua, and Wu Yanze. "Study on Radial Clearance Sealing Performance of Graphite Ring." Journal of Pressure Vessel Technology 143, no. 3 (November 18, 2020). http://dx.doi.org/10.1115/1.4049046.
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Abstract Firstly, the suitable forming method of graphite ring was screened according to compression deformation test, considering the characteristics of radial clearance seal. Then, the compression resilience, radial contact stress and axial sealing performance of graphite packing rings with different density were researched by testing. Research shows: 25% compressibility is the limit of radial clearance compensation ability of graphite packing ring; And the radial contact stress of graphite packing ring on the pipe wall is linearly positively correlated with the axial load, density has little effect on it. Based on the porous media model of gaskets, axial leakage models of three kinds of graphite rings with different density were obtained by experimental fitting and the influence of external working conditions on leakage mode was analyzed, which provide a theoretical basis for the design of graphite ring seal based on leakage rate.