Ensuring uniform thickness of the conductive coating on the inner surface of the hemispherical resonator by magnetron sputtering

The possibilities of technological ensuring of the uniformity of thickness distribution of a thin-film metal coating produced by magnetron sputtering on the inner surface of a thinwalled silica resonator made in the shape of a hemisphere are considered. The possibility of minimizing the thickness of the coating by optimizing the diameter of the annular magnetron emission zone in combination with the distance from the resonator to the target made of sprayed material is shown. A further increase in the evenness of thickness of the coating is possible on the basis of the use of a fixed screen with a hole, the shape and location of which are calculated analytically, and the final configuration of the contour is specified empirically

Assessment of Fluoride Release through Dentin Adhesive in the Alkasite Restorative Material and Giomer

This study evaluated the fluoride release of alkasite restorative material (ARM) and giomer penetrating the dentin adhesive layer. Twenty specimens were prepared for each restorative material, and dentin adhesive with uniform thickness was applied to half of them. The prepared specimens were placed in a polyethylene tube containing 2.0 mL of deionized water and deposited in a 37.0°C water bath for the study duration. The amount of fluoride release was measured on the 1st, 3rd, 7th, 14th, 21st, and 28th days after deposition. The dentin adhesive applied to the ARM and giomer could not completely block the fluoride release; however, it significantly reduced its amount. The cumulative amount of fluoride release of the ARM after 28 days was higher than that of the giomer regardless of the application of dentin adhesive.

Hydroelastic waves propagating along a frozen channel with non-uniform thickness of ice

Hydroelastic waves propagating along a channel covered with ice of non-uniform thickness are considered. The channel has a rectangular cross section. The fluid in the channel is inviscid and incompressible. The ice is modeled as a thin elastic plate. The ice thickness changes linearly. The problem is reduced to the problem of the wave profile across the channel, which is solved using the normal modes of an elastic beam with non-uniform thickness. It is shown that with the decrease in the change in the ice thickness, the modes approach the normal modes of an elastic beam with a constant thickness. The behavior of the dispersion relations of the hydroelastic waves depending on the parameter describing the change in the ice thickness is studied.

The Nanocellulose Fibers from Symbiotic Culture of Bacteria and Yeast (SCOBY) Kombucha: Preparation and Characterization

Symbiotic Culture of Bacteria and Yeast (SCOBY) is a by-product in the form of cellulose polymers produced by bacteria in the kombucha fermentation process. Until now, SCOBY products still have application limitations. Several world designers have succeeded in making works using fabrics based on SCOBY. The resulting fabric has a flexible texture and is brown like synthetic leather. Fabrics based on SCOBY are also considered cheap and more environmentally friendly with short production time. The use of SCOBY as a fabric base material still has problems, where the fabric produced from SCOBY kombucha, directly through the drying process, has the characteristic of being very easy to absorb water. Another problem is that SCOBY production in the kombucha fermentation process is difficult to achieve a uniform thickness and SCOBY production in a large surface area is also difficult to stabilize. The development of SCOBY into cellulose fibers can be done by first changing the structure of SCOBY into nanocellulose. This nanocellulose production can then be developed into nanocellulose fibers in the form of threads and then spun to become a complete fabric. The production of nanocellulose is carried out using cellulase enzymes. It is known that cellulase enzymes can be obtained through the growth of bacteria or specific fungi. One of the groups of fungi and bacteria commonly used to produce cellulase enzymes are Trichoderma and Bacillus.

465 Split-thickness Skin Graft Harvest under Local Anaesthetic: A Single Pass Technique

Adequate local anaesthetic, in harvesting a split thickness skin graft (SSG), involves multiple passes of a needle across the length and width of the marked donor site. We describe a technique using hyaluronidase to uniformly anaesthetise an SSG donor site with one injection, in one pass of one needle. Mix 10mls 1% Lidocaine solution with Adrenaline 1:200,000 with 1 vial Hyaluronidase 1 Unit/ml solution. The mixture is buffered with 1 ml NaHCO3 to neutralise acidity and minimise pain. Mark out the SSG donor site Using a 27G long needle (sterican), enter perpendicular to the skin in the middle of the proximal aspect of the donor site. Inject some local anaesthetic subdermally, creating a mound. Change the angle of the needle to 180 degrees and continue to inject the remaining anaesthetic along one half of the width of the donor site. Using a rolled 4x4 swab, apply firm advancing pressure to distribute the mound across the remaining width and length of marked donor site. As the mound advances, the hyluronidase/anaesthetic mixture will distribute uniformly across the donor site within the same plane. The skin blanches secondary to the adrenaline during its distribution. The technique described is a fast, reproducible way to improve patient comfort through the elimination of repeated passes of a needle, distribute the anaesthetic uniformly across the donor site, and facilitate the acquisition of an SSG of uniform thickness The technique described is a fast, reproducible way to improve patient comfort through the elimination of repeated passes of a needle, distribute the anaesthetic uniformly across the donor site, and facilitate the acquisition of an SSG of uniform thickness

Towards Scalable Large-Area Pulsed Laser Deposition

One of the significant limitations of the pulsed laser deposition method in the mass-production-technologies of micro- and nanoelectronic and molecular device electronic fabrication is the issue of ensuring deposition of films with uniform thickness on substrates with large diameter (more than 100 mm) since the area of the laser spot (1–5 mm2) on the surface of the ablated target is incommensurably smaller than the substrate area. This paper reports the methodology that allows to calculate the distribution profile of the film thickness over the surface substrate with a large diameter, taking into account the construction and technological parameters of the pulsed laser deposition equipment. Experimental verification of the proposed methodology showed that the discrepancy with the experiment does not exceed 8%. The modeling of various technological parameters influence on the thickness uniformity has been carried out. Based on the modeling results, recommendations and parameters are proposed for manufacturing uniform thickness films. The results allow for increasing the film thickness uniformity with the thickness distribution < 5% accounts for ~ 31% of 300 mm diameter substrate.

Charge Density-Versus Time-Controlled Pulse Anodization in the Production of PAA-Based DBRs for MIR Spectral Region

A robust and reliable method for fabricating porous anodic alumina (PAA)-based distributed Bragg reflectors (DBRs), operating in mid-infrared (MIR) spectral region, is presented. The method relies on application of high (UH) and low (UL) voltage pulse sequence repeated in cycles. PAA-based DBR consists of alternating high-(dH) and low-porosity (dL) layers translated directly into periodically varied refractive index. Two anodization modes were used: time- and charge density-controlled mode. The former generated dH + dL pairs with non-uniform thickness (∆d) and effective refractive index (∆neff). It is supposed, that owing to a compensation effect between the ∆d and ∆neff, the photonic stopbands (PSBs) were symmetrical and intensive (transmittance close to zero). Under the charge density-controlled mode dH + dL pairs of uniform thickness were formed. However, the remaining ∆neff provided an asymmetrical broadening of PSBs. Furthermore, it is demonstrated that the spectral position of the PSBs can be precisely tuned in the 3500–5500 nm range by changing duration of voltage pulses, the amount of charge passing under subsequent UH and UL pulses, and by pore broadening after the electrochemical synthesis. The material can be considered to be used as one-dimensional transparent photonic crystal heat mirrors for solar thermal applications.

Numerical Investigation on the Formation and Penetration Behavior of Explosively Formed Projectile (EFP) with Variable Thickness Liner

Explosively formed projectiles (EFPs) are widely used in civil applications and the military field for their excellent impact performance. How to give full play to the energy accumulation effect of explosives and improve the penetration performance has become the main problem of EFP design. The aim of the present study was to investigate the effect of liner structure on EFP formation and its penetration behavior. In order to achieve this, a finite element (FE) model was first established on the basis of the Lagrange and ALE method. Then, formation and penetration performance tests of EFP were performed to verify the validity and feasibility of the proposed FE model, where the configuration, velocity of EFP, and penetration diameter left on the target plate were compared. Finally, by using the proposed FE model, the entire process of the formation and penetration behavior of EFP with axial symmetrical variable thickness liners were analyzed, where spherical-segment liners with uniform and non-uniform thickness were developed. The results were drawn as follows: the numerical simulation error of EFP velocity was less than 5%, and the simulated penetration diameter was compared to the 8.6% error obtained from the experimental method. It demonstrated that the proposed FE model had higher prediction precision. After the explosive was detonated, a forward-folding EFP was formed by the liner with a thin edge thickness, while the EFP formed by the liner with uniform thickness had a backward-folded configuration. It was also found that the liner with a thin edge thickness gave the largest steady velocity of EFP, and it was the lowest by using the liner with uniform thickness. There were two types of loads generated after the formation of an EFP, those were shock wave loading and an EFP, both causing damage in the target plate during the process of an EFP’s penetration into it. The shock wave induced by liners with non-uniform thickness caused higher damage in the target plate, the maximum value of stress was reached at about 4.0 GPa. The forward-folding EFP formed by the liner with the thinnest edge thickness had the largest penetration ability. The backward-folded EFP, owing to the hollow structure, had the worst penetration ability, which failed to penetrate the target plate.