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Detection of hidden defects of aluminum alloy plate with damping coating is a challenging problem. At present, only a few non-destructive testing methods exist to address this engineering problem. Without the restriction of skin effect, remote field eddy current (RFEC) overcomes the interference caused by the damping coating. The RFEC, which has potential advantages for detecting the hidden defects of aluminum plate with damping coating, can penetrate the metal plate to detect buried depth defects. This study aims to test how thick the RFEC sensor can penetrate the metal plate to detect the buried defects.

The magnetic field distribution characteristics are analyzed, the magnetic field intensity distribution is calculated, and the structure and parameters of the coil, magnetic circuit and shielding damping are determined through the two- and three-dimensional finite element simulation methods. Optimal excitation frequency is obtained, and the distance between the excitation coil and detection coil is determined by analyzing the relationship between excitation frequency and remote field points.

Simulation and experimental results verify the feasibility of applying the RFEC detection technology in detecting the hidden defects of aluminum alloy plate with damping coating.

In this paper, the RFEC testing model of hidden defects in aluminum plate sample with damping coating is established by using the finite element method.

It is very important to create a useful cyclic symmetric model for the investigation of the vibration reduction effect of hard-coating blisk. This study aims to develop a cyclic symmetry algorithm which can determine the mode of blisk in the sector coordinate system directly.

Using the exponential and real quasi-equivalent Fourier matrices, the formulas for solving the sector mode were derived, and the relationship between the two kinds of sector modes was also discussed. Based on the proposed cyclic symmetry algorithm, the vibration characteristics of an academic blisk were solved, and the formulas for solving the natural characteristics and vibration responses of the coated blisk were given.

A blisk with NiCrAlCoY+YSZ hard coating on both sides of each blade was chosen as a case to demonstrate the presented method. Based on the verification analysis model, the influences of coating thickness on the vibration reduction effect of the blisk were discussed. The results show that the hard coating has good vibration reduction effect on the blisk even the coating thickness is very thin and the vibration reduction effect of hard coating in the high frequency range is obviously better than that in the low frequency range.

As a large number of reduced order modeling methods of blisk are implemented based on the sector modes, the proposed method which can obtain the sector modes directly will significantly improve the efficiency of dynamic modeling and analysis of the coated blisk structure.

Capillary rise of water in buildings has been an issue of concern among past and present researchers. Despite the research efforts devoted to the proper elimination of the problem in masonry construction, it still remains a challenge that needs to be addressed. The purpose of this paper is to explore treatment mechanisms that can be used to prevent rising damp in new building infrastructure.

In total, 14 test walls are constructed, conditioned, subjected to various treatments and monitored for four years. The treatments applied to the walls include the use of polyethylene damp proof courses, damp proof coatings and dense concrete bases. The walls are then monitored with reference to the two climate seasons in Ghana.

The results highlight that rising damp is present, as suggested by the constant increase and decrease in the height of the water levels in the walls during the rainy and dry seasons, respectively. The findings further reveal that within the four-year period, the walls treated with the damp proof coatings, together with those with the dense concrete bases performed better than those treated with the polyethylene damp proof courses.

The economic and commercial impact of these preventive mechanisms were not considered in this study. A future research can be directed at these issues.

The proposed treatment mechanisms highlight the effectiveness of some treatments applied to walls to prevent the capillary rise of water from the ground into the superstructure.

Building regulations, especially in Ghana and other tropical settings should be amended to include ways to prevent rising damp phenomena by including effective methods against rising damp during the building design or construction.

Series of studies worldwide have been conducted in laboratories to simulate the capillary rise of water in walls of buildings. This is among the few studies that look at how water rises from actual ground conditions into the walls of buildings.

To study the effect of feldspars as inorganic filler on the mechanical and dielectric properties of epoxy coatings.

Coating systems used were of either filler‐free epoxy resin (as reference), or epoxy resin filled with feldspars powder at four different levels by weight. Mechanical properties of the coatings were evaluated via damping hardness and abrasion and impact resistance measurements. Electrochemical impedance spectroscopy measurements were used for the evaluation of the dielectric properties while visual observations of the test panels after salt‐spray test were also made.

The addition of 15 per cent w/w feldspars resulted in a formulation giving the most positive results, e.g. improvement of the coating's mechanical characteristics and dielectric behaviour similar to that of filler‐free epoxy coatings. Practically comparable to this behaviour was that possessed by coatings with 30 per cent w/w feldspars, while further increase of the feldspars content resulted either in a reduction in the extent of the enhancement of the mechanical behaviour or even in a worsening of both mechanical and dielectric characteristics.

Feldspars are the most abundant group of minerals in the earth's crust; it is an inorganic, environmentally friendly material, which exhibits high Mohs hardness. The effects of feldspars in improving the mechanical characteristics of organic coatings, while not causing any reduction in the anticorrosive performance of the polymeric matrix was found through the study.

A new epoxy emulsion coating, combining the proven properties of epoxies with the ease of application associated with emulsion paint, is now being marketed by Sealocrete Group Sales Ltd, Atlantic Works, Oakley Road, Southampton S09 4FL. This is Sealocrete Epoxy Wetcote, which, it is claimed, form a tough, durable and completely protective coating with excellent chemical resistance and adhesion properties. Suitable for interior or exterior use, and even able to be applied successfully to damp surfaces, it has general purposes damp‐proofing, protective coating and decorative applications in the home, industry, the building trades, agriculture and wherever an easily used protective coating is needed.

The paint industry is always intrigued by speciality coatings. Literally thousands of paint formulations have been devised over the years with highly specialized and very frequently intriguing functions. In this latter category is a process described in Japanese patent 19,790 (1971) for painting polka dots upon sheet metal. How often the need for such technology might arise in the life of the average paint chemist is, of course, a moot question. But some comfort can no doubt be drawn from the fact that this unique methodology exists!

The presence of damp can cause a major corrosion situation and also growth of fungus. Although there are often techniques that are perhaps better used to getting at the basic source of this problem, there are many instances when to erradicate the dampness at source is either near impossible or impracticable. It is in these applications in particular that protective covering systems can prove to be the most efficient method of dealing with the problem.

This work sets out to characterise the protective properties of conformal coatings and how they degrade.

The approach dosed several commercial coatings with two different contaminants, a synthetic generic flux mixture of dibasic acids in both a solvent‐ and water‐based carrier, and sodium chloride. The protective properties were monitored using three complementary techniques: surface insulation resistance measurements, sequential electrochemical reduction analysis, and diffusion measurements.

The experimental approach was verified and the SIR measurements were shown to be the most valuable. Coatings offered varying levels of resistance to the contaminants, with the silicone coating being the most resistant. The flux variants generally proved more harmful to the coatings, suggesting that flux diffusion through the coating exceeded that of NaCl and hence led to greater electrochemical corrosion. Flux transmission through the coatings was verified by the diffusion measurements.

The project only investigated a limited number of contaminates on simple single sided boards. Future work will investigate coverage effects and a wider range of contaminants.

The work shows that coatings can allow diffusion of contaminates, particularly organics, which can lead to corrosion. The test methodology described here can be used to characterise coating susceptibility.

This work starts to develop for the first time a test methodology to characterise the protective properties of conformal coatings, and shows that flux, and hence other similar organic contaminants, may represent a protection challenge for some coating chemistries.

Maintenance coatings have several functions but certainly one of their most important is to combat corrosion. Corrosion protection is important in both maintenance and industrial coatings and this is stressed in an article in Chemical Marketing Reporter (June 6 (1983) p. 5, 20). According to this article, which quotes results from a marketing research firm, Margolis Marketing and Research, corrosion resistance will provide the objectives for an important segment of the coatings industry in highway construction and in the automotive industry. The use of salt on highways to melt snow and ice is increasing and this causes billions of dollars of damage to iron and steel each year. U.S. roads are covered with over 10 million tons per year of salt. In the industrial area galvanised steel has become an important component of items subject to rust such as the automobile.

The aim of this paper is to review, briefly and selectively, some highlights of the progress made in the development of damping materials technology for vibration control, in the past two decades, with particular emphasis on the developments sponsored by the US Air Force Materials Laboratory at Wright‐Patterson Air Force Base.