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Journal articles on the topic 'Hermetic seals'

Author: Grafiati

Published: 4 June 2021

Last updated: 13 February 2022

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1

Neilsen, M. K., L. A. Andrews, S. L. Monroe, and H. L. McCollister. "Development of Hermetic Microminiature Connectors." Journal of Electronic Packaging 113, no. 4 (December 1, 1991): 405–9. http://dx.doi.org/10.1115/1.2905427.

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Miniaturization of hermetic packages has provided the incentive to develop a new family of hermetic microminiature connectors. Microminiature connectors, with a pin spacing of 1.27 mm, have previously been available only in the nonhermetic form. New microminiature connectors with compression seal materials, 304 Stainless Steel housings, Alloy 52 pins, and TM-9 Glass insulators, were examined because compression seals are currently used in larger hermetic connectors and are typically designed to create a residual compressive stress state in the insulator during manufacturing. The new microminiature connectors with compression seals were evaluated analytically with two and three-dimensional finite element models and experimentally by fabrication of prototype connectors. The finite element analyses predicted the development of undesirable tensile stress in the insulator during manufacture and identified the mechanism responsible for the generation of tensile stress in the glass. The experimental investigation confirmed the existence of undesirable tensile stress in the glass with the observation of crack development during manufacture. Since the design requirements would not allow the geometric modifications needed to manufacture crack-free connectors with compression seals, insulator materials that generate a matched seal with 304 Stainless Steel housing were developed. Connectors with these matched seals were successfully manufactured.

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2

Radionov, Aleksander, Aleksander Podoltsev, and Grzegorz Peczkis. "The Specific Features of High-Velocity Magnetic Fluid Sealing Complexes." Open Engineering 8, no. 1 (December 31, 2018): 539–44. http://dx.doi.org/10.1515/eng-2018-0066.

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Abstract Studies on the impact of magnetic and centrifugal forces in hermetic magnetic-liquid seals were presented. The results of numerical calculations on the decrease of the impact of the centrifugal force through the use of magnetic flux concentrators on a rotating shaftwere shown. It has been demonstrated that there is a greater possibility for the use of hermetic magnetic-liquid seals in axially symmetrical clearances in gas-steam separation for coke gases.

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3

Loehman, R. E. "Glass Ceramics for Hermetic Metal-Insulator Seals." JOM 38, no. 12 (December 1986): 42. http://dx.doi.org/10.1007/bf03257598.

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4

Donaldson, P. E. K., and E. Sayer. "Technical note: testing hermetic seals of microelectronic packages." Journal of Medical Engineering & Technology 12, no. 1 (January 1988): 26–27. http://dx.doi.org/10.3109/03091908809030154.

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5

Negmatov, Sayibjan, Bahrom Rahmonov, Bakhodir Sobirov, Akbar Abdullaev, Yuldosh Salimsakov, Jakhongir Negmatov, Malika Negmatova, Rustam Soliev, and Dilshod Mahkamov. "Developing of Effective Multipurpose Polymer-Bitumen Compositions." Advanced Materials Research 413 (December 2011): 539–40. http://dx.doi.org/10.4028/www.scientific.net/amr.413.539.

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We researched and developed effective polymer bitumen composites for hermetic of deformities seals of concrete and asphalts roads, bridges, aerodrome and airfields used in hot climate conditions and high lands.

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6

Stack, J. G., and M. S. Acarlar. "Heat Transfer and Thermal Stress Analysis of an Optoelectronic Package." Journal of Electronic Packaging 113, no. 3 (September 1, 1991): 258–62. http://dx.doi.org/10.1115/1.2905404.

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The reliability and life of an Optical Data Link transmitter are inversely related to the temperature of the LED. It is therefore critical to have efficient packaging from the point of view of thermal management. For the ODL® 200H devices, it is also necessary to ensure that all package seals remain hermetic throughout the stringent military temperature range requirements of −65 to +150°C. For these devices, finite element analysis was used to study both the thermal paths due to LED power dissipation and the thermally induced stresses in the hermetic joints due to ambient temperature changes

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7

Murawski, K., K. Aristovich, and H. T. Lancashire. "Selective laser sintering of glass-ceramic bonds using a defocused Nd:YAG laser." International Symposium on Microelectronics 2020, no. 1 (September 1, 2020): 000286–90. http://dx.doi.org/10.4071/2380-4505-2020.1.000286.

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Abstract Protecting miniature implantable electronics may require mm scale hermetic packages. Glass-ceramic bonding by selective laser sintering of glass sealing paste using a defocused Nd:YAG laser is presented. Glass sealing paste (FX11-036, Ferro) is screen printed onto alumina ceramic, clamped in contact with borosilicate glass, and laser treated while heating to 250°C. With the addition of defocusing and a heat source the glass paste reflowed and wetted both the alumina and coverslip surfaces, with an optimal effect between 10 mm and 15 mm defocusing. This method is promising to create electrically non-conductive hermetic seals at the mm scale.

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8

Hung, Y. Y. "Technique for rapid inspection of hermetic seals of microelectronic packages using shearography." Optical Engineering 37, no. 5 (May 1, 1998): 1406. http://dx.doi.org/10.1117/1.601656.

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9

Calnan, Sonya, Stefan Aschbrenner, Fuxi Bao, Erno Kemppainen, Iris Dorbandt, and Rutger Schlatmann. "Prospects for Hermetic Sealing of Scaled-Up Photoelectrochemical Hydrogen Generators for Reliable and Risk Free Operation." Energies 12, no. 21 (November 1, 2019): 4176. http://dx.doi.org/10.3390/en12214176.

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Photo-electrochemical (PEC) systems have the potential to contribute to de-carbonation of the global energy supply because solar energy can be directly converted to hydrogen, which can be burnt without the release of greenhouse gases. However, meaningful deployment of PEC technology in the global energy system, even when highly efficient scaled up devices become available, shall only be a reality when their safe and reliable operation can be guaranteed over several years of service life. The first part of this review discusses the importance of hermetic sealing of up scaled PEC device provided by the casing and sealing joints from a reliability and risk perspective. The second part of the review presents a survey of fully functional devices and early stage demonstrators and uses this to establish the extent to which the state of the art in PEC device design address the issue of hermetic sealing. The survey revealed that current material choices and sealing techniques are still unsuitable for scale–up and commercialization. Accordingly, we examined possible synergies with related photovoltaic and electrochemical devices that have been commericalised, and derived therefrom, recommendations for future research routes that could accelerate the development of hermetic seals of PEC devices.

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10

Terentyev, Vladimir, Aleksei Bausov, and Mihail Toropov. "STUDY OF HERMETIC ABILITY OF A COMBINED FERROFLUIDIC SEALED OF BEARING ASSEMBLIES." Bulletin Samara State Agricultural Academy 6, no. 1 (May 20, 2021): 25–31. http://dx.doi.org/10.12737/44167.

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The purpose of the research is to increase the efficiency of hermetic ability of bearing assemblies by using com-bined ferrofluidic sealed. The research objective is theoretic justification of the maximum concentration of ferro-magnetic particles in fluid, investigation of hermatic ability of a combined ferrofluidic seal under conditions of tem-perature changing and speed of a shaft rotation of packing bearing assembly. The study of hermetic ability of lip and ferro-fluidic sealed was carried out on a test bench, allowing to determine the packing ability of seals both in static and dynamic mode. On the basis of theoretical data, formulas were determined to find the maximum concen-tration of hard and magnetic phases in a ferrofluid, and its composition based on a polyethylsiloxane liquid PES-5 with a 40 kA/m saturation magnetization and a 1.2 Pas dynamic viscosity coefficient was developed. A mixture of magnetite with powdered iron was used as the ferromagnetic phase. Oleic acid was used as a surfactant. Studies to determine hermetic capacity have shown a higher efficiency of the combined ferrofluidic seal compared to the lip one. During static test within the temperature range between 20 to 600C, the critical pressure difference of the com-bined seal was 4-16% higher than that of the lip seal. Temperature increase of the bearing assembly from 20 to 1200C causes a decrease in critical pressure difference of up to 50%. This is due to a decrease in the sedimentative stability of the magnetic fluid as a result of an increase in temperature. Studies show that the combined ferrofluidic seal has a higher hermetic tightness at the starting torque than the standard lip seal. In contrast to the lip seal (which tends to lose its tightness at the starting torque), no leakage of pressure fluid from the sealed unit was observed of the com-bined ferrofluidic one with a pressure drop of 0.094 MPa. The results obtained allow reasonably select the concen-tration of magnetic particles in the ferrofluid, and also prove the prospects of replacing standard lip seals with com-bined ferrofluidic ones.

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11

Zetterer, Th, J. Herzberg, J. Baehr, and K. Waxman. "When Failure is not an Option – Packaging Materials and Technologies for the Reliable Protection of Medical Electronics." International Symposium on Microelectronics 2018, no. 1 (October 1, 2018): 000512–16. http://dx.doi.org/10.4071/2380-4505-2018.1.000512.

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Abstract Enabling high-level electrical performance and smooth optical signal transmission is a key requirement for microelectronics packaging materials. This becomes even more relevant for biomedical applications, in which protection requirements must be met alongside standard performance and signal transmission benchmarks. The major challenge: medical packaging must to provide absolute reliability. Microelectronic components face potentially damaging working environment hazards such as high humidity, extreme temperatures, corrosive chemicals, and bodily fluid – especially in the application cases of implantable, ingestible, and wearable devices. Hermeticity is an important factor in the performance of medical packaging. Non-hermetic packaging, sometimes known as “quasi-hermetic” uses organic materials, such as silicone or plastic over-moldings, that are not designed to withstand extreme conditions and break down over time. Material break down in these types of packages can lead to limited protection by allowing permeation of water and other gases through the polymer structure. Non-hermetic packages typically reach critical permeation levels after a very short period of time. For microelectronic components, even the smallest, hardly detectable traces of hydrogen and water vapor inside a package can compromise the performance and reliability of the encapsulated chips and circuits and potentially lead to interconnect failure, one of the most common reliability failure modes in microelectronic applications. The only way to overcome the challenge of achieving absolute reliability is by using hermetic packaging technologies with inorganic materials, such as glass, ceramics and metal. Unique manufacturing processes of these hermetic components create vacuum-tight seals that prevent moisture and harmful gases from penetrating into the package. Hermetically sealed packages deliver uncompromised reliability, offering long-term protection of sensitive electronics in medical devices – even after thousands of surgical procedures and steam sterilization cycles. This technical presentation will introduce the different reliability levels of packaging materials and provide an in-depth comparison of the respective advantages, disadvantages, and typical application areas of various hermetic packaging technologies. The latest insights into materials and technologies available for high-reliability packaging of medical electronics will be presented.

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12

Lim, William W., David R. McKenzie, and Gregg J. Suaning. "Corrections to Graham’s Law of Effusion for Predicting Leak Rates Through Hermetic Seals." IEEE Transactions on Components, Packaging and Manufacturing Technology 7, no. 3 (March 2017): 379–86. http://dx.doi.org/10.1109/tcpmt.2017.2647738.

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13

Guo, Hongwei, Mengyang Dang, Lei Liu, Qiang Tong, Congcong Zhao, Krista Carlson, Yuxuan Gong, and John W. Hoffman. "Alkali barium glasses for hermetic compression seals: Compositional effect, processing, and sealing performance." Ceramics International 45, no. 17 (December 2019): 22589–95. http://dx.doi.org/10.1016/j.ceramint.2019.07.290.

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14

Hao, Wanli, Fangzhi Li, Yongbo Ma, Weiguang Zhang, Xiaosong Zhou, and Liqun Shi. "Nano-layered-structure interface between Sn-Ti alloy and quartz glass for hermetic seals." Materials Letters 236 (February 2019): 506–9. http://dx.doi.org/10.1016/j.matlet.2018.10.152.

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15

Paul, Brian K., Bindiya S. Abhinkar, and Shiwoo Lee. "High pressure hermetic compression seals for embedding elastomeric membrane microvalves in polymer microfluidic devices." Precision Engineering 35, no. 2 (April 2011): 348–54. http://dx.doi.org/10.1016/j.precisioneng.2010.09.008.

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16

Salzer, Tom. "Advances in Hermetic Projection Weld Sealing." International Symposium on Microelectronics 2019, no. 1 (October 1, 2019): 000550–56. http://dx.doi.org/10.4071/2380-4505-2019.1.000550.

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Abstract In this article, we describe a novel process for hermetic projection weld sealing of semiconductor devices, considered by many to be an important legacy technology from decades gone bye, but not particularly relevant in today's arsenal of sealing technologies. We will demonstrate that with appropriate modifications to be described, this technology can used to seal various high power devices as well as high reliability semiconductors, crystals, hybrid packages, medical electronics, photonic devices, automotive electronics, etc. Its features primarily stem from the fact that it can be used to quickly and efficiently produce true hermetic seals in components. The welding is so rapid, that it is essentially a room temperature technology and the equipment is small enough that it can be housed in an atmosphere controlled chamber filled with any gas that is not explosive. Air, Nitrogen, Argon, Helium and their mixtures are the most commonly utilized gasses. The process is so adiabatic that it can be used to seal many liquids also. In some applications the technology competes against pulsed laser welding, but unlike laser welding the entire seal takes place in a few milliseconds because it is a single discharge, component-shaped spot/projection weld, which means that the entire seam is made in a single high speed discharge. So, in the same time that it takes a laser welding machine to make one of the many small overlapping spot welds required to make a seal, the projection welder has completed the entire operation. This process results in minimal stress and distortion, and maximum hermetic properties, strength and reliability, without requiring electroplating or preforms. Because the weld involves the localized high speed melting of metals, it among the highest energy density processes. A concern with the earlier resistance welding technologies has been the expulsion of particulates, both out of, and into the seal. This expulsion has been systemic and becomes progressively worse as the package size increases. In the course of this presentation we will demonstrate how this concern has been dealt with and corrected. Internal dew points can be held to −40 degrees, or lower if required. Other common applications for this technology include sealing and welding of nuts and studs for hermetic applications and sealing of devices for medical applications that must endure autoclave sterilization. In the course of this presentation, we will take you back to the roots of the original resistance welding process as taught by the early process developers so that you will understand how things have changed, and the reasons for the changes.

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17

Liew, Li-Anne, Ching-Yi Lin, and Y. C. Lee. "Polymer-Based Hermetic Packaging for Flexible Micro Devices." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, DPC (January 1, 2012): 001139–62. http://dx.doi.org/10.4071/2012dpc-tp36.

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In recent years, polymers have been widely adopted as a low-cost, light-weight and high-flexibility alternative to traditional silicon materials for MEMS. However, the majority of polymers do not provide hermetic protection because of their high moisture- and gas permeation rates. Yet, hermetic packaging is critical for many applications such as medical devices [1], RF MEMS [2] and micro heat pipes [3]. In particular, our group has been developing flexible thermal ground planes based on heat pipe technology [3] for advanced electronics cooling applications. Heat pipes require hermetic sealing, while flexibility requires the structural material to be polymer-based. Hermetic packaging methods for MEMS typically include welding, soldering [4], and various epoxies and polymers [1, 2, 5] to bond the parts in a package together. The bond interface is a major potential source of gas and moisture leakage. Although welds and solder joints offer effective hermetic seals, the bond interface is mechanically rigid. On the other hand, flexible bond materials like epoxies typically possess high moisture absorption rate and bonding strength degradation at high temperature [6] while polymers such as BCB [2] or LCP [7] either provide only semi-hermetic sealing or degrade at high temperature. We report a polymer-based hermetic packaging approach using fluorinated ethylene propylene (FEP), which possesses flexibility, high operating temperature compatibility (204°C), chemical resistance, and low water absorption rate. We report results of hermeticity tests in which FEP, solder, and epoxy were used to bond a copper-clad kapton “lid” onto a water-containing copper vessel which is then kept in an oven at 100 °C. The only path for water loss is through the bond interface. We show that the FEP-bonded test vehicles result in negligible water loss comparable to the solder-bonded containers, and far outperforming the epoxy-bonded containers. References: [1] G. Jiang and D. D. Zhou (Ed.), Implantable Neural Prostheses 2, (2010). [2] A Jourdain, P De Moor, K Baert, I DeWolf and H A C Tilmans, J. Micromech. Microeng.,15 (2005) S89–S96. [3] C.J. Oshman, B. Shi, C. Li, R. Yang, Y.C. Lee, G.P. Peterson, and V.M. Bright, J. Microelectromechanical Systems, 20, 2 (2011), 410–417. [4] T. Rude, J. Subramanian, J. Levin, D. Van Heerden, O. Knio, Proc. IMAPS 2005. [5] G. B. Tepolt, M. J. Meschera, J. J. LeBlanca, R. Lutwakb, M. Varghesec, Proc. of SPIE, Vol. 7592, 2010, 759207. [6] E. M. Petrie, Handbook of Adhesives and Sealants, 1st Ed. (McGraw-Hill, 1999), p. 707. [7] C.-D. Ghiu, S. Dalmia, J. Vickers, L. Carastro, W. Czakon, V. Sundaram, G. White, Proc. 1st European Microwave Integrated Circuits Conference, 2006, pp.545–547.

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18

Mathieu, Barry, and Abhijit Dasgupta. "A Fractional-Factorial Numerical Technique for Stress Analysis of Glass-To-Metal Lead Seals." Journal of Electronic Packaging 116, no. 2 (June 1, 1994): 98–104. http://dx.doi.org/10.1115/1.2905512.

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Fracture of glass seals in metallic hermetic electronic packaging is a significant failure mode because it may lead to moisture ingress and also to loss of load carrying capacity of the glass seal. Seal glasses are intrinsically brittle and their fracture is governed by the stresses generated. This study investigates stresses in lead seals caused by handling, testing, mechanical vibration, and thermal excursions. Loads considered are axial tension, bending, and twisting of the lead. More general loading can be handled by superposition of these results. Factorial techniques, commonly used in multi-variable Design of Experiments (DoE), are used in conjunction with finite element parametric simulations, to formulate closed-form regression models which relate the maximum principal stress within the glass seal to the type of loading and geometry. The accuracy of the proposed closed-form equations are verified through analysis of residuals. The analysis reveals the sensitivity of the magnitude of the seal stress to design variables such as the materials and geometry of the seal, lead, and package. Manufacturing-induced problems such as defects and flaws are not considered. An additional purpose for presenting this study is to illustrate the use of design of experiment methods for developing closed-form models and design guidelines from simulation studies, in a multi-variable problem.

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19

Mendoza-Acevedo, Salvador, Luis Alfonso Villa-Vargas, Héctor Francisco Mendoza-León, Miguel Ángel Alemán-Arce, and Jacobo Esteban Munguía-Cervantes. "Improved method to reduce interfacial defects in bonding polydimethylsiloxane layers of microfluidic devices for lab–on–chip applications." Superficies y Vacío 30, no. 2 (June 15, 2017): 25–29. http://dx.doi.org/10.47566/2017_syv30_1-020025.

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This work describes a method to achieve a nearly seamless bonding between two polydimethylsiloxane (PDMS) surfaces. This material is widely used to realize microfluidic systems, and obtaining a strong union is an important step in the fabrication process. From the proposed bonding method, a minimal interface is accomplished, useful for hermetic seals in microfluidic systems. The presented method relies in the surface activation by oxygen plasma and the interaction of said treated surface with uncured PDMS. A comparison of bonding methods is presented in this paper in order to assess the performance of the bonding process and verify the interface formed between the bonded surfaces. The intended application of the presented method is the fabrication of pressure sensors, micropumps, microchannels, microfluidic pumps, valves, mixers and other structures that demand a complete seal over the bonded surfaces.

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20

Barkatt, Aaron, Hamid Hojaji, Vasantha R. W. Amarakoon, and James G. Fagan. "Environmental Stability of High Tc Superconducting Ceramics." MRS Bulletin 18, no. 9 (September 1993): 45–52. http://dx.doi.org/10.1557/s0883769400038021.

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The discovery of high Tc superconductivity in layered cuprate ceramics has so far led to the identification of about 35 distinct superconducting cuprate systems, the latest of which is the 133 K superconducting system Hg-Ba-Ca-Cu-O. For most of their proposed applications, high Tc ceramics have to be resistant to environmental degradation both with respect to atmospheric water vapor, e.g., in storage, and to liquid water (produced by condensation on warm-up from cryogenic conditions). The presence of CO2 is an important factor in both environments. Increasing environmental stability involves improving the processing methods to eliminate pores, cracks, and other macroscopic defects (e.g., highly leachable impurity phases) which are prevalent in materials prepared by solid-state sintering. Furthermore, protective coatings and hermetic seals are necessary in many applications involving films because of small film thickness. (Wires are usually drawn inside metal tubes, which provide protection.)

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21

Isakov, F. "ANALYSIS OF MONI SIS OF MONITORING OF THE A ORING OF THE AT-3 AUTOTRANSFORM TRANSFORMATOR IN T OR IN TashTES MODE." Technical science and innovation 2019, no. 1 (June 11, 2019): 209–17. http://dx.doi.org/10.51346/tstu-01.18.2.-77-0016.

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The article considers the results of the analysis of autotransformers operation mode monitoring. The time diagram of active load current and oil temperature of autotransformer TashTES AT-3 is established and during one year changes of these variables and basic parameters of autotransformer were observed. Technical faults of the power transformer and high power autotransformer are established and methods of their elimination are determined. Damage of transformers and autotransformers with voltage of 110-500 kV of about 30% of the total number of outages which were accompanied by internal short-circuits and two main causes of damage were determined. The main causes of technological failures, which were not accompanied by internal short-circuits, are as follows: 20% of failures in operation of the onload tap-changer, 16% of oil leaks from the bushings, 13% of oil leaks and lowering of oil from the transformer due to violation of welded joints and rubber seals, 4% of engine damage to oil pumps of the cooling system, 3% of pressure increase in high-voltage hermetic bushings, 2% of film protection shell damage. The main reasons of technological violations accompanied by internal short-circuit in the transformer are as follows: breakdown of internal insulation of highvoltage bushings, insufficient short-circuit resistance, wear and tear of winding insulation, breakdown of insulation.

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22

Eidukynas, Rimantas, and Valdas Barauskas. "ANALYSIS OF CONTACT PROBLEMS IN ELASTIC—PLASTIC METAL SEALS/TAMPRIŲJŲ METALINIŲ SANDARIKLIŲ KONTAKTINĖS SĄVEIKOS TYRIMAS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 3, no. 10 (June 30, 1997): 37–42. http://dx.doi.org/10.3846/13921525.1997.10531682.

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One of the most important problems in the design of seal joints is the optimisation of their shape and the material properties. This paper presents the results of the numerical simulation of conical and cantilever seal joints contact problems by using the finite element system ANSYS 5.0A. The temperature and friction have been taken into account. The sealing principle of conical seals, which are usually used as flange joints in networks of pipes, is based on large plastic deformations of seal edges and maintaining the highly elastic property of the whole construction of the seal. Fig 1 presents the scheme of the conical seal used as a base for numerical simulations. The relation between the contact force and displacement in conical seals with various material hardening shows that the contact force is not proportional to the displacement. The latter statement is demonstrated by Fig 2, presenting the results of the numerical simulations, where the curves 1, 2, 3 correspond to the following numerical values of material properties curve 1- E = 2,1.105 MPa, σy = 280 MPa, Eκ1 = 7000 MPa (ε ≤ 0,0125), E&kappa2 = 2500 MPa (0,0125 < ε ≤ 0,0125), Eκ3 = 600 MPa (0,1 < ε ≤ 0,3), Eκ4 = 1000 MPa (ε > 0,3), curve 2—E=2,1.105 MPa, σy = 200 MPa, Eκ = 5.103 MPa; curve 3—E = 2,1.105 MPa, σy = 500 MPa, Eκ = 3.103 MPa. Under displacement 0,7—1,3 mm, the cone seal usually loses stability by exhibiting the second form of instability. Such a sealing joint is not suitable for the practical application as it is not hermetic. Fig 3 shows the deformed shape and contours of the equivalent plastic strains of the above-mentioned conical seal (RAD1=0,153 m, RAD2=0,159 m, h=0,001 m, A=0,0007m, α = 60°, β=0°, ϕ = 10°, γ = 45°, E = 2,1.105 MPa, σy=280 MPa, Eκ1 =7000 MPa (ε ≤ 0,0125), Eκ2 =2500 MPa (0,0125 < ε ≤ 0,0125), Eκ3 = 1600 MPa (0,1 < ε ≤ 0,3), Eκ4 = 1000 MPa (ε > 0,3), ν = 0,3) in one of the loading steps of the solution process. Numerous numerical simulations have shown that the second form of instability is caused by unfavourable loading and boundary conditions for the first instability form. Such numeric results correspond exactly to the experiments. Under high pressure of the working medium (over 40 MPa), such seals collapse by exhibiting the first form of instability. The contact force increases only by 10%, and the collapse occurs when the seal is loaded more than 1,4 mm. V—and λ—form (cantilever) seals may recover from static and 0,1—0,4 mm dynamic displacements due to their high elasticity. Usually such seals possess soft metallic or polymeric coats. The process of the seal deformation is very complex because the contact surface slides and rolls upon the basic surface. In this paper the problem has been solved be using the submodelling techniques of ANSYS. The submodelling involves analysing a coarse model and by subsequently creating the finely meshed “submodel” of the region of interest. The coarse model displacements are applied as constraints on the cut boundary of submodel. In this problem, we will use the region of the whole cantilever seal as the coarse model. The region of interest is the contact zone, so we create the submodel of this region. Due to symmetry, only half a seal needs to be modelled (Fig 4), where RADX = 3 mm,S1 = 5 mm, H1 = 1,7 mm, H2 = 0,5 mm,S2 = 0,5 mm,3 = 2,8 mm, S3=5,5 mm, RAD1 = RAD2 = RAD3 = 1 mm, RADY = 4mm, RADC=30 mm, DD=0,1 mm, δ=0,12 mm, E= 2,1.105 MPa, ν = 0,3. After numerous numerical simulations, the base relations were defined. The maximum stress intensity dependence against the parameters of the arms of the cantilever spring seal elastic zone (Fig 6); ratio of relative seal radius against maximal stress intensity σI, pressure force F and contact pressure q1 (Fig 7). The analysis enabled to obtain the optimised construction of the seal. The elastic-plastic deformation analysis of the coating has been performed. When the loads are small, the stress and strain contours are characteristic of classic Hertzian [1] contact theory. With higher loads, the picture changes significantly. After increasing the contact area width, the plastic zone grows and develops through to the boundaries of the interacting region. By summarising the simulation results were obtained: the relations between the contact width, the approach of the contact surfaces δ, relative contact force Fk and ratio q/σy, when coating thickness is 0,14 mm and radius of the indenter 0,5 mm. The relation q/σy in this case is constant, approximately equal to 16. With the increase of the indenter radius, the ratio q/σy is not constant and increases with an increase of the contact force. The numerical simulations of various seals allow to arrive to the following conclusions: For cone seals the geometric instability (usually in the second form) is exhibited even at computatively small loads. When the loading exceeds 1,2 mm, the elastic structure may acquire an unaxisymmetric form. In the usage of such seals, the following points should be taken into account: it is necessary to match the materials properly. Best suitable materials have higher yield point and higher stiffness hardening; try to keep axisymmetric form of a seal even under the collapse. For this reason it is necessary to keep high requirements; good results are obtained by covering the seals with soft coatings, thus reducing the force. In such way only the coating is subjected to the plastic deformation, while the whole structure remains elastic. Cantilever seals have good elastic properties and do not loose stability. After summarising the numerical simulations results, the suggestions for the rational geometric shape of the cantilever seal have been made. In the design of coated seals it is necessary to take into account that the equivalent plastic strains in the coat layers close to the indenter increase with increasing contact force, decreasing the indenter radius and the coat thickness

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23

Vasantha Geethan, K. Arun, and S. Jose. "Evaluation of stresses in flame resistant materials." Material Science Research India 7, no. 1 (June 25, 2010): 179–86. http://dx.doi.org/10.13005/msri/070122.

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Reliability prediction is fundamental to system design. It involves the quantitative assessment of systems reliability prior to development. For many years the reliability of an electronic system was based, to a great extent, upon the junction temperatures of the semiconductor devices. Substantial efforts were made in the fabrication methods, mounting methods, and cooling techniques of the electronic devices to reduce these hot spot temperatures below 100 °C. This has produced a significant improvement in the reliability and effective operating life of the equipment. However, the electronic failure rates are still too high. Additional reductions in the failure rates must be achieved to further improve the reliability of our electronic equipment. Some of the failure mechanisms that can cause malfunctions in electronic systems are examined in this paper Experience has shown that most of these failures are produced by a mismatch in the thermal coefficients of expansion (TCE) of the different types of materials typically used in electronic assemblies. The mismatch often generates high forces and stresses, which produce fractures and cracks in the electronic components and assemblies. An examination of a large number of avionics failures has shown that most of them are mechanical in nature. They typically involve fractures in solder joints, electrical lead wires, plated through holes (PTH), electrical cables, connectors, adhesive bonded joints, and hermetic seals. These failures are often produced by various combinations of thermal, vibration, shock, humidity, and salt environments, combined with poor manufacturing processes and poor design practices. These failures must be reduced in order to achieve a substantial improvement in the system reliability. The paper aims at presenting the numerical evaluation by finite element analysis of the common class of PCBs under the mechanical stress. This work contributes to the study of vulnerability in packaged electronics by comparing the numerical result with finite element analysis.

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ICHIRYU, Ken, Morio TAMURA, and Fujio SATOH. "Development of Plastic Hermetic Seal." Hydraulics & Pneumatics 26, no. 2 (1995): 203–13. http://dx.doi.org/10.5739/jfps1970.26.203.

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Lenzen, M., and R. E. Collins. "Hermetic indium metal-to-glass-tube seal." Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 18, no. 2 (March 2000): 552–53. http://dx.doi.org/10.1116/1.582222.

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Shiraishi, Akinori, Mitsutoshi Higashi, Kei Murayama, Yuichi Taguchi, and Kenichi Mori. "Wafer Level Package for MEMS with TSVs and Hermetic Seal." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, DPC (January 1, 2011): 002314–35. http://dx.doi.org/10.4071/2011dpc-tha24.

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In recent years, downsizing of MEMS package and high accuracy MEMS device mounting have been strongly required from expanding applications that using MEMS not only for industrial and automobile but also for consumer typified mobile phone. In order to achieve that, it is appropriate to use Silicon package that can be mounted at wafer level packaging. Silicon package is made of monocrystal silicon wafer. The deep cavity is fabricated on monocrystal silicon wafer by Wet or Dry etching. And MEMS device can be mounted on the cavity. The electrical connecting between front side and back side of cavity portion is achieved by TSVs that located on the bottom of cavity. Hermetic seal can be achieved by using glass or silicon wafer bonding method. By using a driver device wafer (before dicing) as the cap for hermetic seal, smaller size and smaller number of parts module can be fabricated. In this report, methods and designs for hermetic seal with wafer level process were examined. Methods that applied were polyimide adhesive bonding, anodic bonding and Au-In solder bonding. Location of TSVs on the bottom of cavity and thickness of diaphragm with TSVs was also examined. Silicon package for piezo type gyro MEMS that designed by the result of evaluation was fabricated. This package used optimized Au-In solder bonding for hermetic seal and optimized location of TSVs for interconnection. That was designed over 50% thinner than conventional ceramic packages. Characteristics of hermetic seal were evaluated by Q factor of gyro MEMS that mounted inside of the silicon package. It is confirmed that performance of sealing are good enough for running of the MEMS.

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Mishra, Ananya, Kasim Mohamed, Prasanna Kumar, and Sathish Kumar Jayagandhi. "Prosthetic Rehabilitation of Maxillectomy Defects, with Single-Piece Open-Hollow Bulb Definitive Obturator." Journal of Evolution of Medical and Dental Sciences 10, no. 16 (April 19, 2021): 1169–73. http://dx.doi.org/10.14260/jemds/2021/248.

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Patients who undergo surgical resection of the maxillo-mandibular structures as a result of trauma, infection or malignancy, suffer from psycho-social setbacks which has a profound impact on their over-all quality of life. 1,2 These defects, especially those following maxillectomy, result in oroantral communication, facial deformation, impaired speech and difficulty in deglutition. For the rehabilitation of patients with such defects, surgical and prosthetic treatment options are available. As, not all patients can be successfully rehabilitated with reconstructive surgeries due to postoperative complications like graft rejection, the extent of the surgical defect and high psychological impact factor associated with repeated surgeries, prosthetic rehabilitation proves to be an alternative treatment option. The prosthetic rehabilitation of such patients is challenging as it requires restoration of the lost form, function and aesthetics, under constantly changing state of post-surgical intraoral tissues, with limited mouth opening. The maxillofacial prosthesis designed to close congenital or an acquired tissue opening, primarily of the hard palate, is known as an obturator. 3 The obturator has two functional components, one seals the surgical defect and the other replaces the lost dentoalveolarstructures.4-7 The design of an obturator may vary depending on the extent of the defect, remnant dentoalveolar complex, soft tissue undercuts and existent muscle physiology.8,9 Among the two designs, solid and hollow, hollow obturators are widely used. The bulb portion of the hollow obturator, which accommodates the surgical defect, can be open or closed9,10and its selection depends on the prosthodontist’s clinical decision-making skills and the ease of fabrication. In this article we have discussed the rehabilitated patients with single-piece, openhollow bulb definitive obturator. Patients undergo extensive maxillary surgical resections due to aggressive lesions like malignancies and deep fungal infections. Prosthetic rehabilitation of such patients with an obturator becomes of paramount importance as it separates the oropharynx from the nasopharynx, reduces the risk of recurrent infections, replaces lost dentoalveolar structures, permits intelligible speech, reinstates mastication and deglutition, restores facial contour and patient’s self-esteem. The bulb portion of the obturator extends into the defect and accommodates it, forming a hermetic seal. In this clinical report, we highlight the success of prosthetic rehabilitation of maxillectomy patients using single-piece, open-hollow bulb definitive obturator. The meticulous follow-up carried out reveals the success of the prosthesis and adds practice-based evidence to the maxillectomy rehabilitation outcome.

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de los Santos, M. A., S. Cardona, and J. Sa´nchez-Reyes. "A Global Simulation Model for Hermetic Reciprocating Compressors." Journal of Vibration and Acoustics 113, no. 3 (July 1, 1991): 395–400. http://dx.doi.org/10.1115/1.2930197.

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This article presents a simulation model for reciprocating hermetic compressors. The acoustical behavior of both admission and discharge circuits is analyzed by invoking the discrete element model. Cavities are considered as elastic elements and ducts as rigid elements with inertia according to this model. Reed valves are modeled as systems of three degrees of freedom, and are studied by using modal analysis. The percussive version of Lagrange equations is used to describe the impact between valves and stops or seats. Results from the theoretical model are checked with those experimentally obtained for a real compressor.

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Buyalich, G. D., and K. G. Buyalich. "Comparative Analysis of the Lip Seal in Hydraulic Power Cylinder." Applied Mechanics and Materials 770 (June 2015): 402–6. http://dx.doi.org/10.4028/www.scientific.net/amm.770.402.

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The natureofthe hydraulic power cylinderseal assembly operation with high working fluid pressure, different geometrical parameters oflip-type seal, is revealed. The method of hermetic sealingprocess modelingaccording to the simplifiedmodelusing finite element method is considered.

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KATAGIRI, Daisuke, Yoshinori YOKOYAMA, Hiroo SAKAMOTO, and Shigeru HAMADA. "Bonding Strength Evaluation for Hermetic Seal of MEMS Package." Journal of the Society of Materials Science, Japan 56, no. 10 (2007): 926–31. http://dx.doi.org/10.2472/jsms.56.926.

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31

K.N., Kulik, Semenenko S.Ya., Marchenko S.S., and Popov P.S. "The technology of the complex sealing and protect of the structural seams of antifiltration precast concrete covering for the diversion canals." Ekologiya i stroitelstvo 2 (2018): 11–18. http://dx.doi.org/10.35688/2413-8452-2018-02-002.

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In the article presents the technology of hermetic sealing of constructive seams of precast reinforced concrete anti-filtration facing of meliorative channels is given. As a complex waterproofing filler, it is proposed to use a U-shaped filler made of glass-reinforced polypropylene of a P-FB random copolymer. The application of this technology provides protection against vegetation germination and a significant reduction in water losses for filtration.

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32

Marinis, Thomas, and Berj Nercessian. "Hermetic Sealing of Stainless Steel Packages by Seam Seal Welding." International Symposium on Microelectronics 2010, no. 1 (January 1, 2010): 000720–30. http://dx.doi.org/10.4071/isom-2010-wp5-paper6.

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Welded stainless steel packages offer a number of advantages relative to those fabricated from kovar or aluminum metals and braze sealed. They are highly resistant to corrosion, especially in aqueous or elevated temperature environments, are mechanically stronger, dramatically so at temperatures above 100°C, exhibit lower outgassing rates, and have better vibration characteristics. Since welded stainless steel packages do not require over plating to facilitate braze sealing, combined material and fabrication costs are lower than kovar or aluminum packages. Also, unlike kovar, stainless steel is nonmagnetic, which is advantageous in many electronic applications. For sealing stainless steel packages, we elected to use seam sealing rather than laser welding for two reasons. Seam sealing subjects the package contents to lower thermal excursions than laser welding because less material is melted to achieve a weld in seam sealing. Second, seam sealing confines the molten material between the cover and package, where as laser welding produces a surface filet. Consequently, there is more opportunity for molten metal to splatter or react with the atmosphere in laser welding than in seam sealing. We successfully developed a process to weld a 2 millimeter thick cover onto a box with dimensions of 75 mm long by 50 mm wide by 15 mm deep using a seam sealer. The box walls were 1 mm thick and were penetrated by a dozen glass insulated feedthrus on one side. Both cover and box were fabricated from 316L stainless steel. A combination of analytical and finite element modeling were used in conjunction with a designed experiment to optimize the process variables of roller angle, speed and pressure, weld current, pulse shape, duration and spacing, number of weld passes, and sealing atmosphere. Weld quality and seal integrity were evaluated by leak testing before and after environmental stressing, mechanical testing and metallographic cross sectioning. The effects of component dimensions and tolerances on seal integrity were also investigated. Particular attention was paid to cover flatness, flange thickness, and tightness of fit between the cover and box. The process development was concluded by conducting a qualification experiment that used the optimized process parameters with controlled variation about their nominal values. A 100% yield of sealed boxes was obtained. These test articles were then subjected to various environmental screening tests, which were all passed with no failures.

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Lim, D. F., J. Fan, L. Peng, K. C. Leong, and C. S. Tan. "Cu–Cu Hermetic Seal Enhancement Using Self-Assembled Monolayer Passivation." Journal of Electronic Materials 42, no. 3 (December 6, 2012): 502–6. http://dx.doi.org/10.1007/s11664-012-2353-6.

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34

Kaur, Navpreet. "Hermetic Seal in Obturation: An Achievable Goal with Recently Introduced Cpoint." International Journal of Clinical Pediatric Dentistry 12, no. 5 (2019): 410–13. http://dx.doi.org/10.5005/jp-journals-10005-1619.

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35

Julián E. Herrera, B., B. Javier MartÍnez, C. Felipe Corredor, U. Luis RodrÍguez, and Robinson Jimenez-Moreno. "Mechanical Analysis of a Hermetic Seal System for Applications in the Industry." Journal of Engineering and Applied Sciences 14, no. 24 (September 30, 2019): 9544–56. http://dx.doi.org/10.36478/jeasci.2019.9544.9556.

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36

Yamada, T., M. Horino, K. Yokoi, M. Satoh, and A. Kohno. "Hermetic seal of ceramics and metals joints by an Al-Si interlayer." Journal of Materials Science Letters 10, no. 14 (1991): 807–9. http://dx.doi.org/10.1007/bf00724744.

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37

Yu, Daquan. "Development of reliable low temperature wafer level hermetic bonding using composite seal joint." Microelectronics Reliability 52, no. 3 (March 2012): 589–94. http://dx.doi.org/10.1016/j.microrel.2011.10.027.

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38

Ogashiwa, Toshinori, Kentaro Totsu, Mitsutomo Nishizawa, Hiroyuki Ishida, Yuya Sasaki, Masayuki Miyairi, Hiroshi Murai, Yukio Kanehira, Shuji Tanaka, and Masayoshi Esashi. "Hermetic Seal Bonding at Low-temperature with Sub-micron Gold Particles for Wafer Level Packaging." International Symposium on Microelectronics 2015, no. 1 (October 1, 2015): 000073–78. http://dx.doi.org/10.4071/isom-2015-tp32.

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Au/Au hermetic sealing was successfully done using a rim structure covered with sub-micron-size Au particles by low-temperature thermo-compression bonding. The easy deformability of sintered Au particles is advantageous in terms of the compliance with surface irregularity as well as the insensitivity of surface flatness. From the deflection of Si diaphragms over the sealed cavity, an inside pressure of 100 Pa and the maximum leak rate in a range of 10−14 Pa·m3/s (He) were estimated, which is sufficient for many MEMS applications.

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39

Kuliukas, Algis V. "Removing the “Hermetic Seal” from the Aquatic Ape Hypothesis: Waterside Hypotheses of Human Evolution." Advances in Anthropology 04, no. 03 (2014): 164–67. http://dx.doi.org/10.4236/aa.2014.43020.

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40

Kurashima, Yuichi, Atsuhiko Maeda, and Hideki Takagi. "Room-temperature wafer scale bonding using smoothed Au seal ring surfaces for hermetic sealing." Japanese Journal of Applied Physics 55, no. 1 (December 9, 2015): 016701. http://dx.doi.org/10.7567/jjap.55.016701.

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41

Wang, Haoran, Yepin Zhao, Zhenyu Wang, Yunfei Liu, Zipeng Zhao, Guangwei Xu, Tae-Hee Han, et al. "Hermetic seal for perovskite solar cells: An improved plasma enhanced atomic layer deposition encapsulation." Nano Energy 69 (March 2020): 104375. http://dx.doi.org/10.1016/j.nanoen.2019.104375.

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42

Memon, Saim, Farukh Farukh, Philip C. Eames, and Vadim V. Silberschmidt. "A new low-temperature hermetic composite edge seal for the fabrication of triple vacuum glazing." Vacuum 120 (October 2015): 73–82. http://dx.doi.org/10.1016/j.vacuum.2015.06.024.

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43

Dallaire, S., B. Arsenault, and A. DeSantis. "Investigation of selected plasma-sprayed coatings for bonding glass to metal in hermetic seal applications." Surface and Coatings Technology 53, no. 2 (September 1992): 129–35. http://dx.doi.org/10.1016/0257-8972(92)90114-p.

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44

Peng, Lan, Lin Zhang, Hong Yu Li, and Chuan Seng Tan. "Cu–Cu Bond Quality Enhancement Through the Inclusion of a Hermetic Seal for 3-D IC." IEEE Transactions on Electron Devices 60, no. 4 (April 2013): 1444–50. http://dx.doi.org/10.1109/ted.2013.2248368.

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45

Ishida, H., and T. Ogashiwa. "Wafer-Level Hermetic Seal Bonding at Low-Temperature with Sub-Micron Gold Particle Using Stencil Printing." ECS Transactions 75, no. 9 (September 23, 2016): 265–72. http://dx.doi.org/10.1149/07509.0265ecst.

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46

Luo, Zhenmin, Jun Deng, Hu Wen, Fangming Cheng, and Yongbin Yang. "Experimental study and property analysis of seal-filling hydrogel material for hermetic wall in coal mine." Journal of Wuhan University of Technology-Mater. Sci. Ed. 25, no. 1 (February 2010): 152–55. http://dx.doi.org/10.1007/s11595-010-1152-2.

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47

Memon, Saim. "Experimental measurement of hermetic edge seal's thermal conductivity for the thermal transmittance prediction of triple vacuum glazing." Case Studies in Thermal Engineering 10 (September 2017): 169–78. http://dx.doi.org/10.1016/j.csite.2017.06.002.

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48

EBINE, Ryusei, Soichiro TANO, Taishi MIYAHARA, and Toshio OTAKA. "Study on a Rankine Cycle System for Waste Heat Regeneration that Installed a Hermetic Seal Rotary Expander." Proceedings of the Symposium on Stirlling Cycle 2018.21 (2018): T02. http://dx.doi.org/10.1299/jsmessc.2018.21.t02.

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49

Romanov, M. K., A. V. Lepinskikh, L. I. Zhuravleva, O. A. Beklenishcheva, and D. V. Kardapol’tsev. "Investigation of the Effect of Different Factors on Metal-Glass Seal Strength in Hermetic Metal-Glass Articles." Glass and Ceramics 76, no. 1-2 (May 2019): 72–76. http://dx.doi.org/10.1007/s10717-019-00135-0.

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50

Donaldson, N. de N. "Effect of the metallic seal of a hermetic enclosure on the induction of power to an implant." Medical & Biological Engineering & Computing 30, no. 1 (January 1992): 63–68. http://dx.doi.org/10.1007/bf02446195.

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