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The purpose of this study is to test the shear-bond-strengths of auto-mixed and manual-mixed self-adhesive resin cement to dentin on long-term high-altitude pressure.

Human molars were embedded in acrylic resin. Sixty composite resin discs were obtained. The composite resin discs were bonded to dentin using hand-mixed and auto-mixed self-adhesive resin cement. After cementation, the samples were stored in artificial saliva and divided into two subgroups (n = 30), hypobaric pressure and the atmospheric pressure group. The specimen underwent three pressure cycles per day for 100 days. The failure types were evaluated after debonding with scanning electron microscopy. The shear bond strength was tested with Universal Testing Machine. Analysis of variances/Tukey post hoc tests were used for statistical analysis. Groups were also evaluated by the Weibull modulus.

Regardless of hypobaric pressure changes, the highest bond strength was examined in auto-mixed Panavia SA samples. A significant difference was found in both auto-mixed MaxCem EC and hand-mixed RelyX U200 group after exposure to hypobaric pressure compared to the control group.

The luting cement-type, mixing methods of cements and environmental pressure changes significantly influence the bond strengths. Dentists can use auto-mixed self-adhesive resins in patients likely to be exposed to hypobaric pressure.

The purpose of this study was to investigate the effect of the environmental pressure changes on the bond strength between zirconia ceramics and adhesive resin cement.

In total, 40 rectangular-shaped zirconium-oxide ceramic specimens were prepared. For surface modification, all zirconia specimens were sandblasted with 50 μm alumina particles. The composite resin discs were bonded to modified zirconia surfaces with resin cement. The specimens were divided into four groups; hyperbaric, hypobaric, hyperbaric + hypobaric and control group. The specimen underwent pressure cycles for 30 days. The shear bond strength test was performed by using the universal testing machine, and failures of the debonded samples were examined with scanning electron microscopy and light microscope.

No significant difference in bond strength was found between the hyperbaric, hypobaric and control groups after 30 days (p > 0.05). However, there was a significant difference in the hyperbaric + hypobaric group compared to the control group (p = 0.022). Also, the Weibull modulus was highest in control group and lowest in the hyperbaric + hypobaric group.

Barometric changes due to flying followed by diving may have an adverse effect on the retention of zirconia ceramics. Care should be taken in the selection of materials for dental treatment of people who are exposed to environmental pressure changes.

ALL ‘plastics’ are generally divided into two groups: the ‘thermoplastics’, which are formed by heating, can be re‐heated after forming, and re‐formed almost ad lib, such as celluloid, xylonite, rhodoid, cellophane, and perspex; and the ‘thermosetting plastics’, which are also formed by heating but cannot yet be re‐formed by the application of heat or any other means, probably the best‐known example of which is the thermosetting variety of bakelite.

For the purposes of this article, adhesives, lutes and putties are excluded even though many of them have applications in the corrosion‐resistant field. Included are the pouring and mortar‐type cements based on bitumen or sulphur, sodium and potassium silicate solutions, silica sols, rubber or synthetic rubber latices, and synthetic resins. The author considers the composition and working properties of these cements and surveys present trends in their use in industry. Recent and possible future developments are covered.

Adhesives of this kind have in recent years become increasingly important for aeronautical purposes. This has been a consequence of the gluing processes adopted in German aircraft manufacture about 10 years ago. Although the application of phenole formaldehyde (bakelite) adhesives for plywood manufacture had already been investigated during 1916–1918 in this country, and although these adhesives were highly recommended by the Adhesive Research Committee in its Report of 1922, every further research and any intended use of adhesives of this kind was discontinued shortly after the war. This is a good example of the slowness in adopting progressive methods in wooden construction.

COMPRESSED laminated (“ improved ”) wood is generally counted among the hardening laminated plastics; it is built up from a large number of very thin veneers (0.0–1.005 in.) which are arranged with parallel grain directions. With the use of thermosetting synthetic resins, the veneers are highly compressed between hot platens. The adhesive, normally of the Bakelite type, is also a strengthening agent, or, with material of high resin content and high density, the wood may be considered as more or less a carrier for the resin, the latter being in this case the main strength‐producing agent.

In this paper, the effects of geopolymer adhesive, the number of CFRP layers and the width of pre-crack on the flexural performance of reinforced concrete beams strengthened with CFRP were studied, and the flexural capacity of strengthened beams was calculated theoretically.

Reinforced concrete beams were strengthened with CFRP by geopolymer adhesive, and flexural load tests were conducted to observe the reinforcement effect. Based on the method of calculating the flexural capacity of reinforced concrete beams, a theoretical calculation model on the flexural capacity of reinforced concrete beams strengthened with geopolymer adhesive bonded CFRP was established.

The test data shown the flexural capacity of epoxy resin adhesive CFRP strengthened reinforced concrete beams is 7.76% higher than that geopolymer adhesive is used. The flexural capacity of reinforced concrete beams strengthened with three layers of CFRP is 1.86% higher than that two layers are adopted. The mean ratio of the test data and the calculation results of the flexural capacity is 0.973, and the mean square error is 0.008. It can be seen that the test data are in good agreement with the theoretical value.

This paper provides data support for the popularization and application of the new environment-friendly reinforcement technology, contributes to the cause of environmental protection, and provides a new method for strengthening reinforced concrete beams.

Where does the coatings industry look for technology which borders on its own and from which it might derive useful leads and ideas? The coatings industry basically depends on the formation of films. Basic to the idea of coatings is the concept that there must be a film and that this film must derive from the vehicle in the coating. To be sure, the film does not represent the entire coating, but it is the sine qua non; and without a film the coating will neither decorate nor protect. There are a host of other technologies that depend on film formation. When the word ‘film’ is mentioned, adhesives and printing inks come to mind, for these technologies also could not exist without the all‐important phenomenon of film formation.

Examines adhesives and in particular how water‐based hot melt and liquid‐reactive are proposed as viable alternatives to solvent‐based types, quite apart from the health and safety and environmental legislation involved.

A numerical simulation of the test beam was carried out with Abaqus and compared with test data to ensure that the modeling method is accurate. An analysis of the effects of the angle between the U-hoop and horizontal direction, the pre-crack height, the pre-crack spacing, and the strength of the geopolymer adhesive on the cracking load and ultimate load of the reinforced beam is presented.

Load tests and finite element simulations were conducted on carbon fiber reinforced polymer-reinforced concrete beams bonded with geopolymer adhesive. The bond-slip effect of geopolymer adhesive was taken into account in the model. The flexural performances, the flexural load capacities, the deformation capacities, and the damage characteristics of the beams were observed, and the numerical simulation results were in good agreement with the experimental results. An analysis of parametric sensitivity was performed using finite element simulation to investigate the effects of different angles between U-hoop and horizontal direction, pre-crack heights, pre-crack spacing, and strength of geopolymer adhesive on cracking load and ultimate load.

Under the same conditions, the higher the height of the pre-crack, the lower the bearing capacity; increasing the pre-crack spacing can delay cracking, but reduce ultimate load. By increasing the strength of the geopolymer adhesive, the flexural resistance of the beam is improved, and crack development is also delayed; the angle between the u-hoop and horizontal direction does not affect the cracking of reinforced beams; a horizontal u-hoop has a better effect than an oblique u-hoop, and 60° is the ideal angle between the u-hoop and horizontal direction for better reinforcement.

According to the experimental study in this paper, Abaqus was used to simulate the strength of different angles between U-hoop and horizontal direction, pre-crack heights, pre-crack spacings, and geopolymer adhesives, and the angles' effects on the cracking load and load carrying capacity of test beams were discussed. Since no actual tests are required, the method is economical. This paper offers data support for the promotion and application of environmentally friendly reinforcement technology, contributes to environmental protection, and develops a new method for reinforcing reinforced concrete beams and a new concept for finite element simulations.