Showing papers on "Blisters published in 2002"
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TL;DR: Ultraviolet B-induced Langerhans cell disappearance appears to be mainly attributable to migration, and apoptosis and migration are the most likely mechanisms.
87 citations
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TL;DR: A surface morphology that arises when ultrathin supported films of poly(d,l-lactide) are immersed in water is described, which is explained in terms of a laterally confined swelling film, which has a buckling instability and releases excess strain energy by wrinkling.
Abstract: In this study we describe a surface morphology that arises when ultrathin supported films of poly(d,l-lactide) are immersed in water. The films are initially flat with a rms roughness of approximately 2 nm. After immersion the surfaces of the films are covered with craters. The craters have a narrow distribution of sizes and are typically micrometers in diameter. They have depths in the 10-100 nm range. In situ atomic force microscopy shows that the craters occur as a result of a blistering process, which occurs when the films delaminate from the silicon substrate. The films buckle away from the substrate to give a nonzero initial diameter and then the blisters proceed to grow until they reach a maximum size. At any point during the growth process, the blisters can be made to collapse by removing the films from water. This phenomenon is explained in terms of a laterally confined swelling film, which has a buckling instability and releases excess strain energy by wrinkling. An expression for the initial buckling wavelength is extracted using the expressions for a buckling plate. Information about the mechanical properties of the films and the surface interaction between the film and substrate can also be obtained by considering the kinetics of blister growth.
41 citations
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TL;DR: In this paper, micro dimples were formed in controlled patterns on carbon-graphite surfaces with a laser and compared to silicon carbide surfaces that were not textured, and a higher rate of blister occurrence on laser textured carbon surfaces was attributed to the inherently low fracture toughness of carbon graphite materials and increased number of sites from which cracks could propagate.
Abstract: Micro-surface textures can create hydrodynamic and hydrostatic lift and thus they have the potential to reduce startup surface traction forces on mechanical seal faces. Lower surface traction forces will reduce the formation of the surface cracks that are commonly characterized as blisters. In this study, micro dimples were formed in controlled patterns on seal face surfaces with a laser. Tests were conducted with texture patterns on a carbon-graphite face or on a mating silicon carbide face. Fewer blisters were detected with textured silicon carbide faces in comparison to silicon carbide faces that were not textured. A higher rate of blister occurrence on laser textured carbon surfaces is attributed to the inherently low fracture toughness of carbon-graphite materials and the increased number of sites from which cracks could propagate.
41 citations
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TL;DR: Findings of elevated sIL-2R levels in blister fluid of patients with TEN are probably related to a local down-regulation of an immunologically mediated cytotoxic reaction and further support the involvement of activated T lymphocytes in the early blisters of TEN.
Abstract: Results: In the blister fluid of patients with TEN, we found significantly higher levels of sIL-2R than in patients with burns, whereas IL-1 levels were higher in the blister fluid of burned patients. No significant differences were found in serum samples of patients with TEN and burns, in either sIL-2R or IL-1. In TEN we also found significantly higher levels of sIL-2R in the blister fluid compared with serum samples, pointing to a predominantly local production contrasting with the low concentration of sIL-2R in the blister fluid of burned patients. Conclusions: Our findings of elevated sIL-2R levels in blister fluid of patients with TEN are probably related to a local down-regulation of an immunologically mediated cytotoxic reaction and further support the involvement of activated T lymphocytes in the early blisters of TEN.
38 citations
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TL;DR: In this paper, two types of blister morphology were identified: single, round and located at the cold spot region whereas the type II blister consisted of several small blisters along a ring around the cold spots.
30 citations
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TL;DR: In this article, the formation of straight-sided blisters has been observed to evolve to periodic distributions of droplets, and the energy variation associated with formation of the droplets has been computed and the morphological change of the film has been discussed as a function of residual stress.
Abstract: Uniaxial compression has been generated in thin films of nickel deposited on a polycarbonate substrate. Atomic force microscopy investigations have emphasized the formation of straight-sided blisters which have been observed to evolve to periodic distributions of droplets. The energy variation associated with the formation of the droplets has been computed and the morphological change of the film has been discussed as a function of the residual stress.
29 citations
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TL;DR: In this paper, the surface modification and deuterium retention after the exposure have been investigated to prove the suitability of such materials in fusion devices in a range from 708 to 843 K.
21 citations
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TL;DR: In this paper, the authors rely on the insitu observation of phone cord delamination propagation in different thin film/substrate systems and show that straight-sided blisters propagate several times faster than the phone cords, and may be followed by thin film fracture along the line of maximum film buckling amplitude.
Abstract: There are many different stress relief mechanisms observed in thin films. One of the mechanisms involves film debonding from the substrate. In the case of tensile residual stress a network of through-thickness cracks forms in the film. In the case of compressive residual stress thin film buckling and debonding from the substrate in the form of blisters is observed. The buckling delamination blisters can be either straight, or form periodic buckling patterns commonly known as telephone cord delamination morphology. The mechanics of straight-sided blisters is well understood. Current study relies on the insitu observation of phone cord delamination propagation in different thin film/substrate systems. Both straight and phone cord delaminations are shown to simultaneously propagate in the same film system. Straight-sided blisters propagate several times faster than the phone cords, and may be followed by thin film fracture along the line of maximum film buckling amplitude. Phone cord delaminations originally start as straight-sided blisters, but then deviate to the periodic phone cord geometry due to the fact that the compressive residual stress in the film is biaxial. Digital analysis of motion recordings shows that partial crack “healing” is present at the curved portions of the phone cords due to the “secondary” buckling pushing thin film back to the substrate. These experimental observations allow for the correct interpretation of the telephone cord delamination morphology.
19 citations
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TL;DR: In this article, the structural analysis of surface blisters on SiC crystals heavily irradiated by He+ and H+ ions using grazing incidence electron microscopy and electron energy-loss spectroscopy is presented.
18 citations
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24 Oct 2002
TL;DR: In this paper, a machine for producing blister packs is described, which includes unrolling means (3,7,21) for unrolling a band of heat-formable material from a bobbin (2) and feeding the band along a predetermined path (P) extending through subsequent stations (5,6,30,8,9,13,13), in which the band (1) is processed.
Abstract: A machine (M) for producing blister packs (10) includes unrolling means (3,7,21) for unrolling a band of heat-formable material from a bobbin (2) and for feeding the band (1) along a predetermined path (P) extending through subsequent stations (5,6,30,8,9,13), in which the band (1) is processed. The above-mentioned stations include a heating station (5), where the band (1) of heat-formable material is heated, a forming station (6), where a plurality of blisters (20) are formed on the band (1), a filling station (8), where the blisters (20) are filled with products, a sealing station (9), where the blister band (1a) is closed with a sealing band (11), and a cutting station (13), where the closed blister band (1ac) is cut into blister packs (10). A further heating station (30) is provided for heating the blister band (la) along the path (P) upstream of the filling station (8), so as to heat the band (1a) to cause a thermal stabilization 20 treatment of the blister band (1a).
17 citations
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TL;DR: In this article, He ion pre-implanted tungsten has been irradiated by electrons to examine synergistic effects of He implantation and high heat load, and depth profile measurements show that He distributes on the surface locally and most of He is distributed in the projected range, however, some of the helium atoms diffuse to deeper region.
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TL;DR: In this article, the deuterium (D+) and helium (He+) ion irradiation was applied to crystalline silicon surfaces and the size and density of the blisters were significantly reduced in the continuously electron-illuminated area.
Abstract: Blistering processes on crystalline silicon surfaces were observed in situ by grazing incidence electron microscopy (GIEM) under deuterium (D+) and helium (He+) ion irradiation. In D+ irradiation, the size and density of the blisters were significantly reduced in the continuously electron-illuminated area. This is attributed to the incident high-energy electrons, which suppress the formation of deuterium terminated cracks by electronic excitation effect. It was also found that irradiation at a higher ion flux give rise to catastrophic flaking before well-separated blisters were formed. In addition, the present study strongly suggests that the crack formation and propagation under D-irradiation start preferentially around the most heavily damaged depth rather than the peak projected range of the implanted D atoms.
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13 Feb 2002
TL;DR: In this article, a method and apparatus for cold-forming an embossed blister from a laminated film is described. But this method is not suitable for manufacturing processes which involve blisters having laminated films which contain a metal foil and polymer layer.
Abstract: The invention herein relates to a method and apparatus for forming (or cold-forming) an embossed blister from a laminated film wherein an indicia is formed on the base of the blister. In particular, the invention involves a single pass process of combining the formation of a blister and the formation of an indicia (embossing) on the blister, wherein the blister-forming pin contains a face with an indicia and is adapted to controllably stretch the laminated film during blister formation to minimize stretching of the film at the base of the blister. The invention is particularly useful in manufacturing processes which involve the formation of blisters having laminated films which contain a metal foil and polymer layer, wherein improved control in the stretching of the laminate during blister formation is desirable.
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12 Jul 2002
TL;DR: In this article, a gripper with suction cups was used to separate blisters for blister packs from a stack of blisters using a set of brush-mounted upper and lower blades.
Abstract: The machine for separating blisters for blister packs from a stack has a gripper (3) with suction cups (33) which fits against the base of the lowest blister. Upper (40) and lower (50) blades and brushes (52) hold the lips of the blisters above while the lowest blister is removed. An Independent claim is included for a method for separating blisters for blister packs from a stack using the machine.
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TL;DR: In this article, carbon fiducial marks are formed during thin-film local delamination processes induced either by superlayer indentation forming circular blisters, or by residual stress relief through telephone cord blister formation.
Abstract: Carbon fiducial marks are formed during thin-film local delamination processes induced either by superlayer indentation forming circular blisters, or by residual stress relief through telephone cord blister formation. Hydrocarbons are sucked into the crack tip during the delamination process, outlining the crack-tip-opening angle, which can be used to back calculate thin-film adhesion using either elastic or plastic analyses presented here. Fiducial marks have been observed in two different thin-film systems, namely Cu/SiO2 and TiW x N y /GaAs. Cu/SiO2 delamination blisters have been cross-sectioned using the focused-ion-beam method, and high-resolution scanning electron microscopy of the cross-sections revealed crack renucleation ahead of the original crack tip. This is attributed to the stress redistribution process due to the dislocation shielding mechanism. At stress intensity levels of 0.33 MPa m½, it is found that four emitted dislocations can account for crack arrest, with renucleation of ...
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TL;DR: In this paper, the growth kinetics of interfacial damage in terms of geometrical properties was observed and statistically analyzed using a two-parameter Weibull cumulative distribution function to represent the blister growth at each time interval.
Abstract: Silicon (Si) wafers passivated with a nitride film, fabricated by low-pressure chemical vapor deposition (LPCVD) and coated with epoxy were used as test specimens to characterize the interfacial degradation. For the sample preparation, the surface was examined by x-ray photoelectron spectrometry (XPS) and contact angle measurement. The stress test conditions were 121/spl deg/C and 100% relative humidity. Optical microscopy was used to monitor the growth of damage as a function of time. Results of electron microscopy and XPS indicate that two different failure modes exist at the interface. One type of degradation is etching of the silicon nitride, Si/sub 3/N/sub 4/ (SiN) film, which appears in the early stages of aging. In more severely etched areas, the concentration of oxygen (O) is quite high and surface cracks develop. The other degradation mechanism is the nucleation and growth of blisters. Phenomenologically, their common characteristics were observed to be rapid growth initially followed by gradual maturing. When a blister became sufficiently large that it could no longer sustain its shape, it collapsed. Often additional blistering propagated subsequently. Blister growth can be accelerated by condensed water that oxidizes the SiN film. Adhesion failure, in the presence of oxygen, is propagated by the degradation of the epoxy silane and SiN film. Precipitate, consisting primarily of sodium (Na), carbon (C) and oxygen (O) with sodium being the main constituent, formed in many of the damage locations. XPS confirmed that a significant source of sodium was the epoxy. Depending on the environmental conditions, the morphology of the precipitate changed. The growth kinetics of the interfacial damage in terms of geometrical properties was observed and statistically analyzed. It was shown that a two-parameter Weibull cumulative distribution function (cdf) could be used to represent the blister growth at each time interval. Naturally, the total blister area increased as the total number of blisters increased. Furthermore, the mean blister area as a function of time was estimated quite well by a power function; however, the scatter about the mean was rather significant. In fact, the statistical variability was sufficiently high throughout that further investigations are warranted. Although progress has been made toward an understanding of the growth kinetics of interfacial damage, the complex processes that compromise the mechanical and electrical integrity require further study.
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TL;DR: The levels of type I and III aminoterminal (PINP and PIIINP, respectively) and type I carboxyterminal (PICP) procollagen propeptides were considerably increased in comparison with the non-irradiated control breast skin, 1–5 years after postmastectomy radiotherapy.
Abstract: (2002). Suction Blisters for the Investigation of Radiation Reactions in Human Skin. Acta Oncologica: Vol. 41, No. 3, pp. 313-314.
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TL;DR: Red, but not white opaque blister covers were suitable for the photostabilisation of nifedipine tablets, however, molsidomine tablets were well protected from light by white opaque blisters.
Abstract: The photostabilising effect of transparent blister covers for light sensitive tablets was investigated. Nifedipine tablets and molsidomine tablets were used as model drug products. Commercially available blister films of different colours were tested. It was demonstrated, that the light protective effect depends on the range of light, which is absorbed by the blister cover. The absorption range of the blister should cover the part of light which is responsible for photodegradation. For both, nifedipine and molsidomine tablets the best photostabilisation was achieved by green blister films. Opaque blisters do not necessarily improve light stability. Red, but not white opaque blister covers were suitable for the photostabilisation of nifedipine tablets. However, molsidomine tablets were well protected from light by white opaque blisters.
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TL;DR: In this paper, a mixed carbon and hydrogen beam was irradiated on tungsten materials and blisters of various sizes were formed in the presence of carbon impurities in the beam.
Abstract: A mixed carbon and hydrogen beam was irradiated on to tungsten materials. In the case in which the carbon concentration and sample temperature were 0.95% and 653 K, respectively, large numbers and blisters of various sizes were formed. But in a low carbon concentration or high temperature case, no significant blisters were formed. It was found that carbon impurities in the beam play an important role in blister formation.
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TL;DR: In this article, a polycrystalline copper surface was physically sputtered by helium ion irradiation with changing the ion fluence and the incident angle, and the flatness of the surface was examined.
Abstract: Polycrystalline copper was physically sputtered by helium ion irradiation with changing the ion fluence and the incident angle. After that, flatness of the surface was examined. For normal incidence, small bubbles and pores were formed at the surface. The average size and areal density increased with the increase of helium ion fluence. By the increase of the incident angle, the copper surface gradually became flat. However, in the case of shallow bombardment with an angle of 67.5°, the surface had a different morphology compared to the other cases. One possible reason may be formations of blisters. In the present experiment, helium ion, which easily produces blisters, was employed. If the ion species such as argon ion and reactive ion is employed, the surface roughness may decrease with increase of incident angle.
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18 Nov 2002
TL;DR: In this paper, a method and apparatus for cold-forming an embossed blister from a laminated film is described. But this method is not suitable for manufacturing processes which involve blisters having laminated films which contain a metal foil and polymer layer.
Abstract: The invention herein relates to a method and apparatus for forming (or cold-forming) an embossed blister from a laminated film wherein an indicia is formed on the base of the blister. In particular, the invention involves a single pass process of combining the formation of a blister and the formation of an indicia (embossing) on the blister, wherein the blister-forming pin contains a face with an indicia and is adapted to controllably stretch the laminated film during blister formation to minimize stretching of the film at the base of the blister. The invention is particularly useful in manufacturing processes which involve the formation of blisters having laminated films which contain a metal foil and polymer layer, wherein improved control in the stretching of the laminate during blister formation is desirable.
01 Jan 2002
TL;DR: In this paper, the growth kinetics of the interfacial damage in terms of geo- metrical properties were observed and statistically analyzed, and it was shown that a two-parameter Weibull cumulative distribution function (cdf) could be used to represent the blister growth at each time interval.
Abstract: Silicon (Si) wafers passivated with a nitride film, fab- ricated by low-pressure chemical vapor deposition (LPCVD) and coated with epoxy were used as test specimens to characterize the interfacial degradation. For the sample preparation, the surface was examined by x-ray photoelectron spectrometry (XPS) and con- tact angle measurement. The stress test conditions were 121 C and 100% relative humidity. Optical microscopy was used to monitor the growth of damage as a function of time. Results of electron mi- croscopy and XPS indicate that two different failure modes exist at the interface. One type of degradation is etching of the silicon ni- tride, Si N (SiN) film, which appears in the early stages of aging. In more severely etched areas, the concentration of oxygen (O) is quite high and surface cracks develop. The other degradation mechanism is the nucleation and growth of blisters. Phenomeno- logically, their common characteristics were observed to be rapid growth initially followed by gradual maturing. When a blister be- came sufficiently large that it could no longer sustain its shape, it collapsed. Often additional blistering propagated subsequently. Blister growth can be accelerated by condensed water that oxidizes the SiN film. Adhesion failure, in the presence of oxygen, is propa- gated by the degradation of the epoxy silane and SiN film. Precip- itate, consisting primarily of sodium (Na), carbon (C) and oxygen (O) with sodium being the main constituent, formed in many of the damage locations. XPS confirmed that a significant source of sodium was the epoxy. Depending on the environmental conditions, the morphology of the precipitate changed. The growth kinetics of the interfacial damage in terms of geo- metrical properties was observed and statistically analyzed. It was shown that a two-parameter Weibull cumulative distribution func- tion (cdf) could be used to represent the blister growth at each time interval. Naturally, the total blister area increased as the total number of blisters increased. Furthermore, the mean blister area as a function of time was estimated quite well by a power func- tion; however, the scatter about the mean was rather significant. In fact, the statistical variability was sufficiently high throughout that further investigations are warranted. Although progress has been made toward an understanding of the growth kinetics of in- terfacial damage, the complex processes that compromise the me- chanical and electrical integrity require further study.