Wet Use Research Articles

Research on the properties of the biocidal drug “Iodosan”

The use of various active substances in the composition of biocides can affect specific chemical properties. Their compatibility, solubility, stability, and corrosion activity are investigated against the background of their ability to affect pathogenic microorganisms. Due to the obtained results, the manufacturer can offer their use in specific conditions (aerosol or wet use, the possibility of use on metal structures, etc.). This publication presents the results of the study of the physicochemical properties of the biocidal agent “Iodosan”, developed by the employees of State Scientific and Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise, based on iodine and lactic acid, dark yellow, with a moderate specific smell of iodine. The starting solution of the product is straightforward to slightly yellowish liquid with a mild iodine smell; after diluting it in tap water, the color of the water remains transparent. The agent is mixed with water to prepare a working solution, “Iodosan”, for wet and aerosol disinfection of objects. The biocidal agent “Iodosan” solution in concentrations of 0.2‒0.5 % has low corrosion activity against the treated test objects. According to research results, the most insufficient corrosion activity of the drug “Iodosan” for aluminum is observed at its concentration of 0.1‒0.5 %, steel, and galvanized steel ‒ 0.1‒0.2 %. Studies have shown that the disinfectant “Iodosan”has a surface tension of 62.03 mN/m at 20 °C. This proved that the drug has a good wetting ability, which affects the disinfecting properties. In working concentrations, the drug has a pH of 5.8. The research results confirmed the effectiveness of the biocidal preparation “Iodosan” for treating premises and equipment surfaces in optimal bactericidal concentrations, and it is recommended for use in production.

Gluing characteristics of Papua New Guinea timber species for various non-structural applications

Papua New Guinea (PNG) has abundant natural forest resources but there are many constraints which need to be addressed to support the development of competitive value-added wood industries. There is a need to develop knowledge and capacity in wood science and processing technologies which support successful domestic value-adding wood processing enterprises. A comprehensive testing program has been developed to assess the glue‐bond strength and performance of selected commercial PNG timber species in various climatic conditions to simulate service conditions in potential market destinations. Two criteria namely shear strength and wood failure have been used to determine if a species can meet the minimum requirements for either dry use or wet use applications. The performance of 24 different PNG commercial timber species has been assessed using a one-component cross-linking polyvinyl acetate emulsion adhesive. The bondability of the selected species has been carefully estimated considering the wood density and wood moisture content for the strength and durability in dry- and wet-use conditions. The testing results show that as the wood density as a wood property factor and moisture content as a service condition factor increase, high shear strength with high wood failure become more difficult to achieve consistently. The highest shear strength and wood failure results were achieved by softwood plantation species and low-density hardwood species. Based on the testing results, the selected species have been classified into bondability classes (bond very well, bond well, bond with difficulty, very difficult to bond).

Investigating the spatial development of corrosion of corner-located steel bar in concrete by X-ray computed tomography

In this paper, the chloride-induced corrosion progression of a corner located steel bar in concrete is investigated by X-ray computed tomography (i.e., X-CT). Corrosion of steel bar is accelerated by placing the reinforced specimen in a wetting and drying cyclic corrosive environment, rather than by the impressed current method. 3D X-CT images are obtained and processed to characterize the different material phases, consisting of, steel bar, mortar, corrosion products and voids/cracks. The corrosion products expansion and concrete cracking are analysed and discussed. It has been found that pitting corrosion is prone to appear around the voids close to the steel bar, mainly due to the pre-existing supply of oxygen and moisture. In addition, a distinct transverse crack has been identified which is caused by non-uniform corrosion along the reinforcing steel bar. Within the cross-section, corrosion has also been found non-uniformly distributed, with the maximum rust layer pointing to the corner edge of the sample. Moreover, the corrosion rust distributions are used to parameterize a recently developed non-uniform corrosion model. This experimentally validated non-uniform corrosion model can be applied to corrosion-induced concrete cracking problems with confirmed accuracy. The combination of the use of wetting and drying cyclic corrosive environment and the X-CT scanning can provide a new method to the non-destructive investigation of corrosion process, rust distribution and corrosion-induced concrete cracking in the reinforced concrete structures.

Spontaneous growth of self-relief wrinkles in freely floating lipid-based nanomembranes, formed on a reactive bath of polyoxometalate aqueous solution

Wetting and capillarity have appeared over the last decadesas potential tools for the guided actuation, self-assembly and nanostructuration, and most recently as powerful “tool-free” techniques of micro-, and nano-fabrication, in the field of nanotechnology. The present work deals with such a use of wetting, achieving for the first time the spontaneous growth of composite (lipid-capped polyoxometalate) nanomembranes, using the reactive spreading film formed by the droplets of a lipid solution, on an aqueous foundation hosting the polyoxometalate ions. Moreover, we show that the internal stress produced by the reactive wetting, and the resulting self-movements of the drop could be accumulated within the drying spreading film, driving the spontaneous occurrence of wrinkles, in the freely floating nanomembranes that are thus formed. Finally, we showed that gravity-driven scaling relations for buckling instabilities apply to these spontaneously occurring wrinkles, allowing the in situ characterization of the physical properties of the nanomembranes. This approach that allowed producing floating nanomembranes of “lipid-capped Keggin ions” that were collectable as freestanding nanosheets may constitute a potential route for the fabrication of a wide range of functional (copolymers/metal nanoparticles) nanocomposite membranes.

Composite material with improved structural, acoustic and thermal properties

A method of forming a multilayer insulation material formed of an acoustical composite layer and a first thermal layer is provided. The acoustical and insulting layer is formed of a polymer based thermoplastic material and reinforcing fibers. Preferably the reinforcing fibers are wet use chopped strand glass fibers (WUCS). The acoustical composite layer may be formed by opening the WUCS fibers, blending the reinforcement and polymer fibers, forming the reinforcement and polymer fibers into a sheet, and then bonding the sheet. A first thermal layer formed of one or more polymer based thermoplastic organic materials is then positioned on a first major surface of the acoustical composite layer. A second thermal layer of polymeric fibers may be optionally positioned on a second major surface of the acoustical composite layer. The multilayer acoustic material may be utilized in semi-structural and acoustical applications.

High Precision with the Whole Earth Telescope: Lessons and Some Results from XCov20 for the roAp Star HR 1217

AbstractHR1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of nonradial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating frequency spacings of 33.3 μHz and 34.6 μHz, with a sixth mode at a problematic spacing of 50.0 μHz (which equals 1.5 × 33.3 μHz) to the highfrequency side. Asymptotic pulsation theory allowed for a frequency spacing of 34 μHz, but hipparcos observations rule out such a spacing. Theoretical calculations of magnetoacoustic modes in Ap stars by Cunha (2001) predicted that there should be a previously undetected mode 34 μHz higher than the main group, with a smaller spacing between it and the highest one. The 20th extended coverage campaign of the Whole Earth Telescope (XCov20) has discovered this frequency as predicted by Cunha (2001). Amplitude modulation of several of the pulsation modes between the 1986 and 2000 data sets has also been discovered, while important parameters for modelling the geometry of the pulsation modes have been shown to be unchanged. With stringent selection of the best data from the WET network the amplitude spectrum shows highest peaks at only 50 μmag and formal errors on the determined amplitudes are 14 μmag. Some lessons for future use of WET for the highest precision photometry on bright stars are discussed.

The Pigmentation of Acrylic Resins*

Acrylic resins may be divided into two main categories—solvent‐bome and water‐borne systems—and these have been further subdivided into two groups, namely solutions and dispersions. Problems associated with the pigmentation of acrylic resins are discussed, and methods of assessing the wetting properties of the system are mentioned. The use of wetting and dispersing agents is examined, and the concept of the hydrophilic‐lyophilic balance (HLB) value is investigated in this context. Pigmentation is one important factor that must be considered in assessing the exterior durability of acrylic resins, certain types of which are ideal media for metallic finishes because of their excellent polishing and weathering properties. The phenomenon of geometric metamerism associated with metallic finishes is discussed.

切削の用具方法と窩壁の精度

The smoothness of cavity walls prepared with various cutting instruments and methods was microscopically compared in their sections, as follows.Little difference was observed between the wall finished with the dentate bur and the plain bur of same form. The fineness of the bur blades seemed to be more important for the wall smoothness, and the fine cut tapered fissure bur without crosscut made the best wall. Therefore, it is quite preferable to finish the cavity margins or marginal bevels with such burs (No. 600-602) .Little difference was observed between the wall finished with chisel and that finished with burs.The wall finished with the dry carborundum point was much coarser than those finished with burs, but it became a little smoother when the point was used under pouring water.The walls cut with the diamond point were very rough in both dry and wet use, and so they must be finished with fine cut burs afterward. However, one should consider that the smoothness of the walls cut with carborundum or diamond points depends on the fineness of their crystals.