Sealant Layers Research Articles

Experimental and Numerical Study on the Shear Performance of the Stone Panel–Panel Joint in Stone Cladding

The evaluation of the shear performance of stone panel–panel joints (SPPJs) in stone cladding has important engineering significance, as it plays a crucial role in stone cladding failure. The purpose of this paper is to analyze and predict the influence of the dimension and the Young’s modulus of sealant on the shear performance of SPPJs. Based on monotonic and cyclic loading tests, the effects of Young’s modulus and the dimension of sealant on the failure characteristics, stress–strain characteristics, stiffness degradation, and energy dissipation capacity of an SPPJs were investigated. According to finite element analysis, the strain distribution of an SPPJ under monotonic loading was analyzed for different sealant widths and number of sealant layers. The results indicate that the failure modes of SPPJs change with the variation of sealant amount. As the Young’s modulus of the sealant increases, the shear failure strength and shear yield strain of SPPJs increase. The increase in sealant thickness reduces the shear failure strength and stiffness of SPPJs. Based on the same shear strain, the increase in the sealant thickness enhances the cumulative energy consumption of SPPJs. The strain concentration zone of the specimens with two sealant layers in unilateral SPPJs becomes larger with the increase in sealant width.

In-vivo durability of Pro Seal in patients with fixed orthodontic appliances: A controlled clinical trial

This clinical trial aimed at studying the durability of an orthodontic sealant (Pro Seal) used on tooth surfaces for protection against white spot lesions. A total of 35 patients (18 females, 17 males; 17.57 ± 1.36 years) were recruited. Eligibility criteria included healthy patients of both sexes (age > 14 years), absence of labial caries, absence of defective enamel, absence of extensive restorations, and optimum oral hygiene. The participants received a single application of Pro Seal on the bonded teeth. The sealant covered the labial enamel surrounding the brackets. Participants were recalled monthly after sealant application, during which sealant layers were evaluated using an ultraviolet lamp. The assessment was realized using an index similar to the adhesive remnant index (ARI). A total of 30 participants completed the trial. ARI values dropped significantly (P < 0.001) and reached <1.5 at T1 on the index used. An ARI value of 2 was chosen as the threshold below which a tooth presented an insufficient sealant layer. The right and left sides of both jaws did not show any statistically significant difference (P > 0.05). ARI values of homolateral teeth revealed few statistically significant differences between upper and lower teeth. No statistically significant difference between the two sexes (P > 0.05) existed. No harm or disturbance was reported by any of the participants. This study demonstrated that a single application of Pro Seal is effective for 4 weeks and should be renewed monthly. No interjaw, intrajaw, or intersex significant differences were found.

Effect of Processing Conditions on Heat Seal Strength for Peelable Heat Sealing of Multilayered Polyethylene Films with Different Sealant Layers

ABSTRACTThe effect of heat sealing temperature on peelable heat seal strength (HSS) before and after the sterilization, often used industrially, was investigated for one of either polyethylene (PE) multilayered films with various inner sealant layers consisting of two high density PEs (HDPEs), a linear low density PE (LLDPE) or low density PE (LDPE). To attain similar HSS, heat sealing at a temperature close to the melting peak temperature (Tm-p) was needed only in the case of LDPE. Heat sealing behavior at higher temperatures, to attain higher HSS, was also investigated for HDPE and LDPE. High HSS, as well as suppressed reduction of HSS after the sterilization, was achieved for HDPE at a heat sealing temperature well below its Tm-p. An Increase of HSS with the increase of dwell time was also observed. On the other hand, for LDPE, high HSS and its stability after the sterilization were achieved only when the heat sealing temperature was increased to the value equivalent to its Tm-p. Improvement of the processing conditions for the shortening of the processing period was also investigated. For HDPE, higher sealing bar temperature was needed to gain similar HSS when the dwell time of the heat sealing was shortened from 4 to 2 s, whereas the attained maximum temperature at the interface was found to be similar. The characteristics of the heat sealed portion, judged from the relation between HSSs before and after the sterilization, were not affected by the dwell time of heat sealing, indicating that the shortening of the processing time by appropriate raising of the sealing bar temperature is possible.

Multilayered Alkyd Resin/Nanocellulose Coatings for Use in Renewable Packaging Solutions with a High Level of Moisture Resistance

A surprisingly simple and rapid methodology for large-area, lightweight, and thin laminate coatings with remarkable moisture barrier properties is introduced. Commercially available paperboards are coated with thin layers of nanocellulose. The nanocellulose coating induces a surface smoothening effect on the coated sheets as characterized by environmental scanning electron microscopy and white light interferometry. A moisture-protective layer of renewable alkyd resins is deposited on the nanocellulose precoated sheets using a water-borne dispersion coating process or lithographic printing. Through an auto-oxidation process, the applied alkyd resins are transformed into moisture sealant layers. The moisture barrier properties are characterized in detail by water vapor permeability measurements at different levels of relative humidity. The water vapor barrier properties of the nanocellulose precoated substrates were significantly improved by thin layers of renewable alkyd resins. The effect of the alkyd res...

Measurement of the thickness of U-30MES-5NT and VGM-L sealing compound layers in aircraft products using the ultrasonic nondestructive testing method

A method for measuring the thickness of sealant layers between glass-fiber reinforced plastic and metallic parts of airframes accessible only from one side is proposed. The method is based on use of general-purpose ultrasonic flaw detectors and special-purpose laser-acoustic equipment. It is shown that the developed method allows for measurement of sealant layers with thicknesses less than the ultrasonic wave length.

A digital image-based micro-flow-batch analyzer

This paper introduces for the first time the combination of digital images taken with a webcam and a micro-flow-batch analyzer as a novel strategy for implementing quantitative chemical analysis. The digital image-based micro-flow-batch analyzer (DIB-μFBA) was formed using urethane-acrylate resin, glass slides and ultraviolet lithography. The glass slides were used as sealant layers on both sides of the substrate urethane-acrylate and provide the necessary transparency to the microsystem to conduct studies using digital images. DIB-μFBA uses digital images obtained from a webcam with CCD sensor, based on the RGB (red–green–blue) color model. The analyzer was used for determining the tannins in green tea employing the well-known ferrous tartrate method. All standard solutions were prepared in-line, and all analytical processes were completed by simply changing the operational parameters in DIB-μFBA control software. The paired t test, at a 95% confidence level, showed no statistically significant differences between results obtained by DIB-μFBA and the spectrophotometric reference method. The proposed microsystem presented satisfactory physical and chemical properties while keeping the flexibility, versatility, robustness and multi-task characteristics of conventional flow-batch analysis. Therefore, it was possible to build a low-cost device with high sample throughput (about 190h−1) and reduced reagent consumption (about 300 times less than the reference method), contributing to the basic principles of green chemistry and the advancement of micro-analytical procedures.

Laser fluorescence of dentin caries covered with a novel nano-filled sealant

The aim of the present study was to assess the possibility to measure caries-induced laser fluorescence underneath a novel nano-filled fissure sealant. Sixty freshly extracted human teeth with occlusal dentine carious lesions were horizontally divided, exposing the respective lesion. Teeth were randomly assigned to three groups: (I) white fissure sealant with filler particles (Fissurit F, Voco), (II) clear fissure sealant without filler particles (Fissurit, Voco) and (III) novel experimental fissure sealant with nano-filler particles (Voco). Starting with a sealant thickness of 3 mm, laser fluorescence measurements (DIAGNOdent, KaVo) were performed after finishing the sealant surfaces with polishing papers, reducing the material at intervals of 0.5 mm until the sealant was removed completely. Evaluating a thickness of 0.5 mm, both the clear (83 % of the baseline fluorescence after fine grit polishing) and the white sealant (25 %) did not allow to measure baseline fluorescence (p < 0.05) with no fluorescence reduction in the experimental sealant group (p > 0.05). With increasing sealer thickness, fluorescence was influenced even by the experimental material (89 % of the baseline value at 1 mm). However, by using the experimental material, statistically significant higher fluorescence values than those for the other materials under study (p < 0.05) were obtained. Thicker sealant layers and coarse grit polishing caused a decrease of laser fluorescence in all groups (p < 0.05). Employing the experimental nano-filled sealant, laser fluorescence measurements for caries detection can be performed through thicker sealant layers compared to conventional sealant materials. Thus, it might be possible to use this material to assess a caries progression underneath the sealant and administer an appropriate therapy in due time.

Investigation of Automotive Detailing Products by Ellipsometry and Contact Angle Analysis

Within the automotive detailing community, there is much discussion focusing on the application of waxes and sealants to enhance and protect paint, and there are a very large number of commercial products on the market. The general idea behind the application of such products is that a wax or sealant layer or layers can increase gloss and “depth of colour”, provide protection against degradation by ultraviolet rays and also make it easier to keep the paint surface clean by shedding and repulsion of rain water. In this paper, the performance of several commercially-available automotive waxes and sealants is examined. In the absence of any available published work, we have used ellipsometry to determine the thicknesses of applied wax and sealant layers and have quantified the water beading eect by measuring the contact angles of water with the wax films.

Optimisation of Glass Composite Sealant for Intermediate Temperature Solid Oxide Fuel Cells

Glass ceramic and glass composite were investigated for use as sealant between SOFC components and materials, metallic interconnect of Fe 78 Cr 22 steels and anode supported Ni/YSZ-based fuel cell. An alkaline earth aluminoborosilicate glass worked as the base glass with magnesium oxide particles added as filler to the composite. Thin sealant layers (60-120 μm) of the alkaline earth aluminoborosilicate glass ceramic formed discontinuous sealant layers with good bonding to the fuel cell materials, but with only moderate bonding to the interconnect materials, regardless of type and bonding temperature. The glass composite (31 vol% MgO filler) prepared to match the coefficient of thermal expansion (CTE) of the cell and interconnect materials, CTE ∼13 x 10 -6 K -1 , showed excellent bonding to both the fuel cell and the interconnect, Crofer 22APU, at anode and cathode conditions and the bonding temperatures 850°C and 950°C. Bonding to the other interconnect, Sandvik 0YC44, was not as good and after thermal cycling, even cooling of the interface, cracks separated seal and interconnect materials with the presence of a barium chromate layer adjacent to the interconnect indicating poor wetting during heat-up sequences. Excessive corrosion reactions at the three-phase boundary between air, sealant and interconnect were observed and may limit the industrial potential of the sealant. The glass composite seal was tested gas tight after sealing fuel cell and interconnect at 850°C in a short stack test showing encouraging results for sealing behaviour and moderate thermal cycling of the interfaces.

Analysis of the Effects of Thin Sealant Layers in Aircraft Structural Joints

A general method is devised for determining the effects of thin layers of sealants or adhesives on the mechanical behavior of riveted lap joints using e nite element analysis. The resulting method, thin adhesive layer analysis (TALA), models the sealant layer with normal and shear spring elements. The TALA method is validated by comparison with existing solutions for both linear high-modulus, and nonlinear low-modulus, adhesives. It is then used to model sealants for aircraft-riveted lap joints. The analyses reveal that sealant layers introduce large increases in the in- and out-of-plane displacements, reduce bending and stress concentration factors (SCF), and increase the fatigue life of riveted lap joints.

An ultrasonic wheel-array sensor and its application to aerospace structures

This paper describes the development of an ultrasonic wheel-array sensor scanning system. The system operates at 10 MHz using a 64-element array transducer which is 50 mm in length and located in a fluid-filled wheel. Thewheel is coupled to the test structure dry, or with a small amount of liquid couplant. An aperture is swept along the array forming a B-scan at each measurement position. The wheel is rolled over the surface of the test structure and a defect map (C-scan) is generated in real-time. The tyre is made from a soft, durable polymer which has very little acoustic loss. The rapid scanning is facilitated by an embedded PC which controls all of the functions of the array transmit and receive module as well as undertaking signal processing of the received waveforms. Three application studies are presented. These are the detection of embedded defects in a thick-section carbon composite test block, the detection of cracking and disbanding in a carbon composite skin-stringer sample and the inspection of sealant layers in an aluminium aircraft wing structure. In each application, the wheel-array sensor was found to produce C-scans of comparable quality to an immersion system with scanning times reduced by factors of 25-50.

Rapid ultrasonic inspection of ageing aircraft

The requirement for rapidly detecting corrosion and disbands in large areas of lap joints in transport aircraft has prompted the development of various new NDT methods and large-area imaging systems. QinetiQ has developedultrasonic array technology in collaboration with Diagnostic Sonar Ltd and evaluated the inspection performance and the potential speed of inspection. The crucial factors in this development were the achievement of high speed as well as high spatial and depth resolution to allow interrogation of sealant and adhesive layers and the characterisation of corrosion. A highly-innovative ultrasonic array probe has been developed that is capable of the high frequency response and broad bandwidth required for lap-joint inspection of ageing aircraft. The array covers a 124 mm swathe and scans at a speed of 4 m (13 ft) per minute with a I mm scan pitch. Scanning software was developed to allow scanning at the maximum pulse-repetition frequency allowed by the ultrasonic flaw detector. Another critical issue was the coupling of a long array into the structure. Data on the latest focused array will be presented, with images scanned on real aircraft structure. Technology transfer of the array has been a successful part of this project. The ultrasonic array is commercially available front Diagnostic Sonar Ltd, an NDT manufacturer in the UK, and the software to control it is available as an upgrade of current commercially-available equipment.

Tensile strength of heat-sealing part of laminated film used for liquid package bags—effect of material and thickness variations of sealant layers : Journal of JSNDI, Vol. 45, No. 12 p. 874 Futase, K.; Shimamoto, A.; Takahashi, S.; Aoki, H.

Tensile strength of heat-sealing part of laminated film used for liquid package bags—effect of material and thickness variations of sealant layers : Journal of JSNDI, Vol. 45, No. 12 p. 874 Futase, K.; Shimamoto, A.; Takahashi, S.; Aoki, H.

On painted ceilings…the techniques of Baroque murals in England

Abstract This paper discusses the findings of an analytical investigation into the materials and techniques of five Baroque wall paintings, produced by an art historically and technologically coherent group of painters, during the late seventeenth and early eighteenth centuries in England. The analysis attempted to define the composition and stratigraphy of the paint, ground, sealant and surface plaster layers, as well as the range of pigments and organic media in use. Later restoration and conservation materials, in particular varnishes and retouchings, were noted.

LITERATURE ABSTRACTS

GENERAL PRINCIPLES Modeling of Expansion and Water Solubility Index of Wheat Starch During Extrusion Cooking. W. Cai and L.L. Diosady Viscoelastic Characteristics of Whey Protein Systems at Neutral pH. P.B. Fernandes The Influence of Caseins on the Rheology of Karrageenan Gels. M.G. Lynch and D.M. Mulvihill Rheological Description at the Minimum Gelling Conditions of kappa‐Carrageenan/Locust Bean Gum System. P.B. Fernandes Rheological Behavior of a Hydrophobically Associating Water Soluble Polymer. T. Aubry and M. Moan Reliability of Dynamic Mechanical Thermal Analyses (DMTA) for the Study of Frozen Aqueous Systems. G. Blond Starch Alterations in Hard‐to‐Cook Beans (Phaseoh vulgaris). E. Garcia Dynamic Gelling Properties of Myofibrillar Protein from Skeletal Muscles of Different Chicken Parts. Y.L. Xiong (corresponding author) and S.P. Blanchard Chemical Structure, Molecular Size Distributions and Rheological Properties of Flaxseed Gum. W. Cui Stickiness of Oryzenin and Starch Mixtures from Preharvest and Postharvest Rice Grains. J. Chrastil Impact of Heating on Carrot Firmness: Contribution of Cellular Turgor. L.C. Greve, K.A. Shackel, H. Ahmadi Impact of Heating on Carrot Firmness: Changes in Cell Wall Components. L.C. Greve Activity of Softening Enzymes during Cherry Maturation. D.M. Barrett Freeze‐Cracking in Foods as Affected by Physical Properties. N.‐K. KimMETHODOLOGY AND INSTRUMENTATION A Comparison of the Adhesion of Film Sealant Layers to Cooked‐in‐the‐Bag Ham (Res. Note). T.E. Goodman Simultaneous Evaluation of Shear Rate and Time Dependency of Stirred Yoghurt Rheology as Influenced by Added Pectin and Strawberry Concentrate. S. Basak and H.S. RamaswamyINSTRUMENTAL MEASUREMENTS Flow Behavior of Cooked Maize Flour Suspensions and. Applicability of Mathematical Models. Sila Bhattacharya Comparison of the Steady Rheological Characterization of Normal and Light Mayonnaises. M. Pons, M.J. Galotto and S. Subirats Characterization of the Rheological Properties of Yoghurt: A Review. T. Benezech and J.F. Maingonnat Peach Firmness Determination by Puncture Resistance, Drop Impact and Sonic Impulse. X. Zhang, M.L. StoneSENSORY MEASUREMENTS Analysis of Textural Changes in Hard Cheese During Mastication by Progressive Profiling. F.R. Jack, J.R. Piggott and A. PatersonFACTORS AFFECTING TEXTURE Selected Skeletal Alterations to Improve Tenderness of Beef Round Muscles. H. Wang, J.R. Claus and N.G. Marriott Effect, Development and Optimization of Mixing Temperature, Time and Particle Reduction in the Manufacture of Restructured Beef Steak. J. H. Thomas Jr., J.‐F.C. Meullenet and J.A. Carpenter Influence of Salts and pH on the Firmness of Olives in Acid Conditions. M. Brenes, P. Garcia and A. Garrido Various Blanching Treatments Affect Final Texture and Total Fiber Content of Peeled Processed Asparagus. M.T. Sanchez‐Pineda‐Infantas, G. CanoMuiioz and J.R Hermida‐Bun Cooking Time. Grinding and Moisture Content Effect on Fresh Corn Masa Texture. B. Ramirez‐Wong, V.E. Sweat, P.I. Torres and L.W. Rooney Sensory and Physical Properties of Chocolate Chip Cookies Made with Vegetable Shortening or Fat Replacers at 50 and 75% Levels. W.L. Armbrister and C.S. Setser The Research on the Rheological Properties of Soybean Protein Isolate. Chen Zongdao, Li Deyuan, Wang Guangci, Bao Xianjin Effects of Carrageenans and Xanthan Gum on the Texture and Acceptability of Low Fat Frankfurters. G.S. Mittal and S. Barbut

Film Type Effects on Meat-to-Film Adhesion Examined by Scanning Electron Microscopy

The purpose of this study was to examine the meat binding interface of different film types under scanning electron microscopy (SEM). Chopped breast meat was cooked in four film types with chemically different sealant layers (three binding and one nonbinding). Replicate 2.5-cm2 (1-in2) sections were cut from each bag then peeled and mounted on glass slides. Samples were then frozen, freeze dried, and gold sputter-coated or stained with osmium tetroxide for examination using SEM. Observations of micrographs indicate visible meat adhesion in the three binding films and insignificant amounts of meat present on the nonbinding film. Purge was observed in all treatments; however, increased amounts were seen in nonbinding films and associated with areas of reduced meat-to-film adhesion.

Burner Rig Evaluation of Ceramic Coatings With Vanadium-Contaminated Fuels

The performance of yttria-stabilized zirconia (YSZ), ceria-stabilized zirconia (CSZ), and magnesia-stabilized zirconia (MSZ) coatings was evaluated using an atmospheric burner rig; test environment contained compounds of vanadium, sodium, and sulfur. The coatings were deposited by plasma spraying and electron beam physical vapor deposition (EB-PVD); sputtered sealant layers of hafnia, alumina, and platinum were deposited on the YSZ coating. The tests were performed for up to 500 hours at 1650°F and 1300°F. The tests were designed to simulate the deposit chemistry and sulfur trioxide partial pressures expected in a marine gas turbine engine operating on contaminated fuel. YSZ, CSZ, and MSZ coatings all underwent reaction in the burner rig environment; the reaction products and their effects on spallation were varied. MSZ was by far the most reactive, readily forming MgSO4 in both 1650°F and 1300°F tests. The observed reaction products provided a measure of “protection” for the bond coat by preventing molten salt infiltration for the duration of the test. The mechanism of ceramic spallation is discussed. Sputtered overlayers of platinum, hafnia, and alumina did not prevent salt infiltration and reaction with the underlying ceramic, although no reaction product between the overlayer and the salt was observed.