Showing papers on "Blisters published in 2013"

Surface modification of tungsten and tungsten–tantalum alloys exposed to high-flux deuterium plasma and its impact on deuterium retention

Abstract: Samples of tungsten and tungsten-tantalum alloy (with 5 mass per cent of Ta) were exposed to high-flux deuterium plasma at different fluences. The surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS). In the high fluence range of similar to 3.5 x 10(26)-10(27)m(-2), multiple large-size blisters are formed on the W surface, while blisters on the W-Ta surface are considerably smaller in size and number. Deuterium retention in this fluence range was found to be systematically higher in W than in W-Ta. Correlation between the evolution of the blistering patterns and the TDS spectra as a function of fluence suggests that trapping in the sub-surface cavities associated with blisters is the predominant trapping mechanism in tungsten in the case of high fluence exposures. We attribute the lower retention in W-Ta under the investigated conditions to the weaker blistering.

Graphene Blisters with Switchable Shapes Controlled by Pressure and Adhesion

Abstract: We created graphene blisters that cover and seal an annular cylinder-shaped microcavity in a SiO2 substrate filled with a gas. By controlling the pressure difference between the gas inside and outside of the microcavity, we switch the graphene membrane between multiple stable equilibrium configurations. We carried out experiments starting from the situation where the pressure of the gas inside and outside of the microcavity is set equal to a prescribed charging pressure, p0 and the graphene membrane covers the cavity like an annular drum, adhered to the central post and the surrounding substrate due to van der Waals forces. We decrease the outside pressure to a value, pe which causes it to bulge into an annular blister. We systematically increase the charging pressure by repeating this procedure causing the annular blister to continue to bulge until a critical charging pressure pci is reached. At this point the graphene membrane delaminates from the post in an unstable manner, resulting in a switch of gra...

Ion effects in hydrogen-induced blistering of Mo/Si multilayers

Abstract: The role that energetic (>800 eV) hydrogen ions play in inducing and modifying the formation of blisters in nanoscale Mo/Si multilayer samples is investigated. Such samples are confirmed to be susceptible to blistering by two separate mechanisms. The first is attributed to the segregation of H atoms to voids and vacancies associated with the outermost Mo layer, driving blister formation in the form of H2 filled bubbles. This process can occur in the absence of ions. A second blister distribution emerges when energetic ions are present in the irradiating flux. This is attributed to an ion-induced vacancy clustering mechanism that produces void blisters. The defects and strained states associated with the Mo-on-Si interfaces provide the preferred nucleation points for blistering in both cases. The effects of ions are ascribed to promotion of hydrogen uptake and mobility, in particular through the Si layers; to the generation of additional mobile species in the Si and Mo layers; and to the creation of new blister nucleation points. In addition to directly stimulating blistering via vacancy clustering, ions modify the development of H2-filled blisters. This is most evident in the formation of multi-component structures due to overlapping delaminations at different layer interfaces. This affect is attributed to the introduction of active transport of hydrogen from the H2 filled blisters across the outermost Mo-on-Si interface to the underlying layers. Ion-induced variations in hydrogen uptake and distribution and in the rates of blister nucleation and growth produce lateral differences in blister size and areal number density that create a macroscopic concentric pattern across the surface.

The formation of friction blisters on the foot: the development of a laboratory-based blister creation model.

Abstract: Background/Purpose: Friction blisters on the foot are a debilitating pathology that have an impact on activities of daily living and can severely impair function. The purpose of this study was to test the hypotheses that digital infrared thermographic imaging will reveal: 1) a correlation between load application to the skin and the creation of blisters, and 2) a correlation between thermographic readings and contact thermometric temperatures. Methods: Apparatus was developed to cause the formation of heel blisters through controlled load application (70 kPa). One foot of each of the 30 healthy volunteers (21 men and 9 women), with an age range of 31 ± 8 years, was subjected to load until a blister formed, after which load application ceased and temperature measurements were taken at set times during the following 5.5 h. Temperature measurements were also taken using a contact thermometer. Results: The majority of the participants (77%) blistered within 18 min of load application. All the blisters created showed significant increases in local temperature compared to baseline during blister creation (P 8). Conclusion: These results suggest that thermographic images may prove useful for the remote assessment of traumatically damaged foot skin.

Blistering of atomic layer deposition Al2O3 layers grown on silicon and its effect on metal–insulator–semiconductor structures

Abstract: In this work, a study of the influence of the processing conditions on the blistering of Al2O3 layers grown by atomic layer deposition (ALD) on silicon substrates is presented. The phenomenon occurs when the as-deposited layers are annealed at high temperature in a N2 atmosphere. The characterization of the blistering in terms of density and dimensions indicates that the higher the annealing temperature the higher the density but also the smaller the blister diameter, while the thicker the oxide the larger the blisters. The processing of the blistered layers to obtain Al-Al2O3-Si structures enhances the blistering phenomenon and at the same time affects the silicon surface underneath the blister. This has been evidenced by chemical etching of the deposited layers that have revealed in circular silicon voids of the size of the blister. The influence of the oxygen precursor used in the ALD process has also been investigated, showing that the blister size is reduced when using O3 instead of H2O. Finally, the use of a thin thermally grown SiO2 layer is shown to avoid blistering of Al2O3 films.

Self-sealing shells: blowouts and blisters on the surfaces of leaky wind-blown bubbles and supernova remnants

Abstract: Blowouts can occur when a dense shell confining hot, high-pressure gas ruptures. The venting gas inflates a blister on the surface of the shell. Here we examine the growth of such blisters on the surfaces of wind-blown bubbles (WBBs) and supernova remnants (SNRs) due to shell rupture caused by the Vishniac instability. On WBBs the maximum relative size of the blister (Rbstall/R) is found to grow linearly with time, but in many cases the blister radius will not exceed 20 per cent of the bubble radius. Thus blowouts initiated by the Vishniac instability are unlikely to have a major effect on the global dynamics and properties of the bubble. The relative size of blisters on SNRs is even smaller than on WBBs, with blisters only growing to a radius comparable to the thickness of the cold shell of SNRs. The small size of the SNR blowouts is, however, in good agreement with observations of blisters in the Vela SNR. The difference in relative size between WBB and SNR blisters is due to the much higher speed at which gas vents out of WBBs, which translates into a greater energy flux through a rupture of a given size from interior gas of a given pressure. Larger blisters are possible if shell ruptures are bigger than expected. We expect the observed velocity structure of SNR shells to be affected by the presence of blisters until the shell is no longer susceptible to ruptures, since the initial expansion of blisters is faster than the ongoing expansion of the shell.

Adhesion of graphene sheet on nano-patterned substrates with nano-pillar array

Abstract: An array of gold nano-pillars is fabricated on silicon, before chemical vapor deposited graphene is transferred to the substrate. Intrinsic intersurface attraction pulls the monolayer into intimate contact conforming to the substrate geometry, but the pillars support an array of circular blisters. A simple delamination mechanics model is constructed to extract the materials and interface properties. The graphene-gold interfacial adhesion energy is found to be γ = 450 ± 100 mJ m−2 by measuring the blister dimension. Should the ratio of pillar height to inter-pillar separation falls short of (γ/Eh)1/4 with graphene elastic modulus, E and thickness, h, the blisters stay isolated; otherwise, adjacent blisters coalesce. Critical design guidelines are set for graphene devices.

Micro-scale delaminating and buckling of thin film on soft substrate

Abstract: In this paper, a simple process is suggested to estimate the interfacial toughness of the material system ?aluminum film/soft PDMS substrate?. The specimen, i.e. the aluminum film deposited on the soft polydimethylsiloxane (PDMS) substrate, is subject to a tensile load, and delaminating and buckling of aluminum film are observed in the perpendicular direction to the tensile strain. With the aid of the buckling blisters, the interfacial toughness of the material system is estimated. Large deformation is considered during the buckling of the thin film, and the interfacial toughness is deduced from a fracture theory. Besides, the evolution from one single blister to three blisters and then four blisters is observed in situ under microscope. This simplified method has potential applications to flexible electronics in which interfacial toughness of the metal film/soft substrate must be well controlled.

Kinetic evolution of blistering in hydrogen-implanted silicon

Abstract: Silicon wafers have been implanted with hydrogen at high fluence. The kinetic evolution of the buckling structures has been observed in situ by atomic force microscopy during a thermal annealing at 200 °C. It is shown that the blistering of the silicon wafers occurs at the first stage of the annealing without any noticeable threshold. The deflection of the blisters continuously increases with time, and some blisters are observed to coalesce. The time evolution of the internal pressure inside the cavities is finally determined from the blister dimensions with the help of an elastic analytical model.

On the formation of blisters in annealed hydrogenated a-Si layers

Abstract: Differently hydrogenated radio frequency-sputtered a-Si layers have been studied by infrared (IR) spectroscopy as a function of the annealing time at 350°C with the aim to get a deeper understanding of the origin of blisters previously observed by us in a-Si/a-Ge multilayers prepared under the same conditions as the ones applied to the present a-Si layers. The H content varied between 10.8 and 17.6 at.% as measured by elastic recoil detection analysis. IR spectroscopy showed that the concentration of the clustered (Si-H)n groups and of the (Si-H2)n (n ≥ 1) polymers increased at the expense of the Si-H mono-hydrides with increasing annealing time, suggesting that there is a corresponding increase of the volume of micro-voids whose walls are assumed from literature to be decorated by the clustered mono-hydride groups and polymers. At the same time, an increase in the size of surface blisters was observed. Also, with increasing annealing time, the total concentration of bonded H of any type decreases, indicating that H is partially released from its bonds to Si. It is argued that the H released from the (Si-H)n complexes and polymers at the microvoid surfaces form molecular H2 inside the voids, whose size increases upon annealing because of the thermal expansion of the H2 gas, eventually producing plastic surface deformation in the shape of blisters.

Ultrashort laser-driven stable-buckling of blisters in chirped mirror

Abstract: Multilayer dielectric mirrors (niobium pentoxide/silica) were irradiated by single 800 nm-38fs laser pulses. A circular blister feature appeared in the chirped mirrors at a wide range of laser fluence, while only existed above a few percent of the damage threshold for the high-reflector. Absorptive source of laser energy can be determined by combining theoretical simulation with focused ion beam technology. Mechanical analysis with a linear-elastic buckling model reveals the blister evolution belonging to a stable-buckling process until the blister radius confined by limited laser spot size.

Suppression of hydrogen-induced blisters in SK4 carbon steel alloy by friction stir processing

Abstract: The feasibility of using friction stir-processing technique as a microstructural refining method for preventing hydrogen-induced blisters of SK4 carbon steel alloy containing microstructure of hard cementite particles in a ductile ferrite matrix was examined. Amount and size of hydrogen-induced blisters decreased in the stirred layers with increasing rotation speed and completely disappeared when rotation speed attained 400 rpm because of the formation of a hard and fine microstructure consisting of pearlite, martensite, and retained austenite instead of that containing hard spheroidized cementite particles in a soft ferrite matrix. Interfaces between ferrite matrix and cementite particles were the preferential sites for the hydrogen blisters initiation.

Characterization of Blistering and Delamination in Depleted Uranium Hohlraums

Abstract: Blistering and delamination are the primary failure mechanisms during the processing of depleted uranium (DU) hohlraums. These hohlraums consist of a sputter-deposited DU layer sandwiched between two sputter-deposited layers of gold; a final thick gold layer is electrodeposited on the exterior. The hohlraum is deposited on a copper-coated aluminum mandrel; the Al and Cu are removed with chemical etching after the gold and DU layers are deposited. After the mandrel is removed, blistering and delamination are observed on the interiors of some hohlraums, particularly at the radius region. It is hypothesized that blisters are caused by pinholes in the copper and gold layers; etchant leaking through these holes reaches the DU layer and causes it to oxidize, resulting in a blister. Depending on the residual stress in the deposited layers, blistering can initiate larger-scale delamination at layer interfaces. Scanning electron microscopy indicates that inhomogeneities in the machined aluminum mandrel are...

Investigation of Internal Pressure and Stress in the Buckled H-implanted Ge Layer

Abstract: Ge samples were implanted at RT and 300 °C by 100 keV H+ ions for a fluence of 1 × 1017 ions/cm2. The surface buckling was observed after post-implantation annealing in the samples implanted at RT. However, for the implantation at 300 °C, surface exfoliation occurred in the as-implanted state. Stylus profilometry revealed that in the case of samples implanted at RT, lateral size of the blisters varied between 3––20 μm, with maximum vertical deflection of the blisters in the range of about 8–55 nm. The lateral size and maximum vertical deflection of the blisters were measured to be about 3–30 μm and 50–210 nm, respectively, for the implantation at 300 °C. AFM showed thickness of the buckled layer to be about 856 and 890 nm for the implantation at RT and 300 °C, respectively. The internal pressure and stress in the buckled layer have been investigated using Foppl-von Karman theory (FvK) of thin plates.

Axial temperature gradient-adjustable insulation structure applied to growth of sapphire single crystals by Kyropoulos method

Abstract: The invention provides an axial temperature gradient-adjustable insulation structure applied to growth of sapphire single crystals by a Kyropoulos method. The insulation structure is arranged in a stainless steel bucket; metal sheets made of tungsten or molybdenum are adopted as heat shields; the heat shields comprise a horizontal heat shield, an oblique heat shield and a vertical heat shield; gaps among the shields are vertically supported by molybdenum strips at intervals; inner and outer filling regions filled with hollow blisters are spaced through the molybdenum strips between the stainless steel bucket and the vertical heat shield; the inner filling region is filled up with ZrO2 hollow blisters; the outer filling region is filled with the ZrO2 hollow blisters or Al2O3 hollow blisters. According to the insulation structure, the axial temperature gradient distribution in a furnace is adjusted by adjusting the height of the outer filling region; the position and the range of a meltback region for crystal growth are adjusted, so that the crystal surface temperature distribution is more gentle, the probability of crystal cracking caused by excessively high heat stress is reduced, the formation of a convex liquid-solid interface in a crystal growth process is facilitated, and the crystal quality is improved.

Blister sheet holder for the verification of the contents thereof

Abstract: Embodiments of a holder for a blister sheet used to manage prescription pills are described herein. The holder solves the problem of limited space in filled blisters of a blister sheet during visual verification of the contents thereof by including a frame to receive the sheet in such a way that at least some of the blisters are positioned in close proximity to verification receptacles also provided on the holder to temporarily receive part of the blisters' content.

Treatment and Prevention of Foot Friction Blisters

Abstract: Treatment and Prevention of Foot Friction Blisters M ost of us whowalk, run, hike, or bike are well aware of the pain and discomfort caused by a simple foot friction blister. These hot spots and eventual blisters can make what was supposed to be an enjoyable workout a miserable hobbling experience. The U.S. military is well aware of the detrimental effects of blisters on mission readiness and complications from what seemed to be a simple foot problem. Blisters have been shown to reduce a soldier’s mobility in the field, lessen his or her concentration, and affect critical decision-making skills (12,17). Complications from blisters including cellulitis, sepsis, and death are reported and occur between 2.5% and 5% in military personnel (2,13). Health and fitness professionals and recreational and elite athletes alike should have basic knowledge of those factors that influence blister formation, how to treat blisters should they occur, and, most importantly, how to prevent them. Foot blisters may be the most common sports injury. The incidence of blisters in marathon runners is 0.2% to 39% (15). During military training, the blister incidence ranges from 5.4% to 69% (8,9,17). During Operation Iraqi Freedom I (OIF I), 33% of deployed military reported friction blisters during their deployment (4). Hikers also experience blisters with an incidence up to 48% (12). Clearly, blisters are a common problem among recreational athletes, elite athletes, and military personnel. A friction blister is caused by frictional shear forces that cause a split or cleavage within the outermost layer or epidermis of the skin. As the forces or number of cycles of friction increase, a blister cleft forms and fills with plasma-like fluid, forming the blister within the epidermis (1,7). Friction blisters only form on those areas of the body where the stratum corneum section of the epidermal layer is quite thick; palms of the hands and soles of the feet. Note that chaffing occurs on other areas of the body where the stratum corneum is relatively thin. For example, friction blisters do not form on our inner thighs where the skin is much thinner. By identifying those factors that most influence blister formation, an athlete may reduce the risk by avoiding them or preparing for them. Common factors include moist damp feet, foot temperature greater than 104-F, emollients like petroleum jelly after an hour of exercise, tobacco use, heavier pack loads, and lack of an ability to train in a shoe (i.e., ‘‘foot harden’’) (11,16). Among women aged 26 to 34 years who had a history of blisters and those soldiers who were not able to ‘‘foot harden’’ before their deployment, the highest risk of blister formation during OIF I was observed (4). The goals of treatment are to minimize pain, limit the size and severity of the blister, prevent complications such as skin infections, and optimize return to full sport/recreational activities. Clinicians have varying opinions about how to treat blisters. However, a classic article by Cortese et al . elucidates the most accepted method of treatment (5). Blisters smaller than 5 mm and ‘‘hot spots’’should bemanaged conservatively. They should not be unroofed or drained. Instead, protect the blister from pressure with a protective covering such as moleskin, a doughnut pad, a Blist-O-Ban dressing (SAM Medical Products, Tualatin, OR), or a hydrocolloidal gel pad (3). One product has not been proven to be superior over another. For blisters larger than 5 mm, wait 24 hours, clean the skin well, and then drain the blister under sterile technique from the periphery of the blister. Do not unroof the blister unless the ‘‘roof’’ is torn and likely to curl or wrinkle, causing more irritation to the underlying skin. Also, if the fluid material drained appears cloudy, opaque (possible infection), or foul smelling, then the blister should be unroofed and consider starting oral antibiotics. Cover the drained blister with an antibacterial ointment and check daily for signs of infection. Moleskin or another protective covering can be applied to minimize pressure and frictional forces on the healing blister. Many other anecdotal treatment options exist, and some may have validity; however, scientifically sound research needs to be done to confirm their efficacy. Medical Report

Failure Investigation of Hydrogen Blistering on Low-strength Carbon Steel

Abstract: The current study assesses the root causes of hydrogen blisters on low strength carbon steel equipment. For this purpose, some experiments including hardness test, non-destructive test (NDT), metallography, and fractograpghy are conducted. The microstructure of two blisters is assessed by means of optical microscopy and scanning electron microscopy (SEM). The microstructural studies show that the steel plate has some inclusions and banded ferrite/pearlite structure. The energy dispersive x-ray spectroscopy (EDS) results indicate that these inclusions mainly contain Mn, S, Al, Ca, and Si. The results show that the inclusions and planar imperfections found in the NDT have been the nucleation locations for blisters in the plate. Remediation action plans are recommended to prevent further occurrence and growth of hydrogen blisters.

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Abstract: High temperature oxidation of aluminium alloys has been a major problem of heat treatment processes. The theory suggests that degradation as a result of long time exposure to high temperatures in the presence of water vapour results in oxidation process which releases hydrogen that diffuses into metal to form hydrogen pores; thus leading to subsurface porosity or blisters. In this study, an examination of the blister formation during Strain Induced Melt Activated process of aluminium alloys were carried out and oxides (i.e. bifilms) were found in the morphology of blisters. Thus, it is suggested that the blistering occurs in the presence of bifilms in aluminium alloys.

Blistering Behavior during Oxide Scale Formation on Steel Surface

Abstract: Blistering occurs when oxide scale is swollen during oxidation. Blistered scale causes surface defect problems when it is rolled. Present study investigated the nucleation and growth behavior of blistering when steel is oxidized at high temperature. The following conclusions are drawn. Blistering phenomenon has the nucleation and growth process. At the nucleation stage scale is delaminated at the scale/metal interface. The gas compositions inside blisters at this stage are CO, CO2, and N2. The steel surface inside blisters is oxidized while the stage changes from nucleation to growth. At the growth stage, the separated steel surface from the scale is not oxidized.

Device for accommodating a drug blister

Abstract: The present invention relates to a novel device for accommodating and storing blister packs, particularly pharmaceutical blisters, and for releasing a tablet or capsule from the blister pack using a means for punching the cover film of the blister.

Drug blister packaging

Abstract: The utility model discloses a drug blister packaging which comprises a polyvinyl chloride (PVC) membrane and aluminum foil which are compounded into a whole. Forming blisters are arranged on the PVC membrane. Drug particles or capsules are stored inside the blisters. The drug blister packaging is characterized in that the plurality of rows of blisters are arranged, the portion where each row of blisters is arranged of the PVC membrane is independently divided into blocks and provided with peripheral circular corners, a point-broken line is arranged between each two adjacent blocks of the PVC membrane, and two drug particles or two capsules are stored inside each blister. The drug blister packaging can increase the packaging quantity of the drug particles or the capsules under the same page size and save packaging cost. In addition, the drug blister packaging can further improve convenience of drug use and fully reflect humanized design from a detailed aspect.

Blister red packet

Abstract: The utility model discloses a blister red packet, and belongs to the technical fields of red packets and blisters. The blister red packet comprises a packet body and blisters, and is characterized in that the blisters are applied on the packet body. The blister red packet has the advantages that third dimension of characters and pictures on the packet body is strong after the blisters are applied on the packet body, and therefore attractive effect is achieved.

From nanovoids to blisters in hydrogenated amorphous silicon

Abstract: AFM and FTIR spectroscopy were applied to study the relationship between surface blisters and nanovoids in annealed hydrogenated a-Si. The influence of the H bonding configuration on the way the nanovoids give rise to the blisters is discussed. Annealing causes an increase of the polymers density. As they reside on the voids walls their density increase causes an increase of the voids volume. The polymers may release H inside the voids with creation of H2 gas, whose expansion, upon annealing, further contributes to the volume increase of the voids till the formation of surface blisters.

Apparatus and method for determining the average layer thickness and the permeation rate of a packaging material

Abstract: An apparatus for determining the average layer thickness l of a flat packaging material for pharmaceutical packagings, in particular blisters and/or bottles, by means of a capacitive determination during which the opposite outer surfaces of the packaging material are provided with electrodes.

Seal for preventing blister on foot caused by shoe

Abstract: PROBLEM TO BE SOLVED: To provide a seal for prevent blisters on feet by shoes, which is thin and small in contact area with the internal shoe surface.SOLUTION: In the seal, a plurality of tapes in the form of strips of paper are adhered and fixed in parallel to one adhesive surface of the sheet body at appropriate intervals.

Twinset ceramic blister and manufacturing method thereof

Abstract: A twinset ceramic blister and a manufacturing method thereof are provided, relating to the technical field of electric light source material preparation The method comprises the following steps: a forming a pair of ceramic blister blank of the same shape, the blank being formed by capillaries (1) and a cavity body (2); b forming one combination ring (3) on a combination surface of the cavity body (2); c printing a layer of thin slurry for bonding on the surface of the combination ring (3) of each blister blank to be jointed; d positioning the two blister blanks by using a fixture, so that the slurry on the surface of the combination ring (3) is bonded; and e drying the jointed blisters, and taking out the blanks bonded together after the slurry is dried; and performing sintering at high temperature and finally forming a twinset ceramic blister The present invention has the following advantages: the process is simple, the joint manner is reliable, no deformation and dislocation appears on the exterior of the jointed blanks, and the transmittance of the whole blister is not affected after the sintering at high temperature