Papers by Keyword: Capillarity

Abstract: Liquid composite molding (LCM) is a widely used group of various different processing techniques allowing to produce small, medium or even very big sized components from prototype level up to series production. During the infiltration it is necessary to run the process in a way preventing void formation. The typically used textile reinforcing structure results in a dual-scale impregnation consisting of micro impregnation within the constituent yarns of the textile structure and a macro impregnation between the yarns. Capillary rise experiments on flat textile samples are used and the well-known Lucas-Washburn equation has been extended to cover the special configuration. A porous capillary wall is assumed to better represent the three-dimensional nature of capillary networks within reinforcing textiles. An according test rig is presented. Accurate experimental results are gained and capillary radii are computed simple and fast via curve regression.

Abstract: Investigation of the effect of low-pressure NLTP in nitrogen, argon, propane-butane and air on the properties of a multilayer medical-purpose material based on polypropylene used for the manufacture of sanitary-hygienic and medical products. It is shown that after plasma treatment of argon, nitrogen, propane-butane, the surface polarity of the CMC material changes significantly, as evidenced by a decrease in the wettability angle and an increase in capillarity. The most significant changes in indicators are observed in the case of plasma treatment in argon and nitrogen. However, in the case of argon, less processing time is required to achieve the effect. Plasma treatment leads to a slight decrease in tensile strength, no more than 10-15%. It is also shown that when plasma is treated in an argon atmosphere, such characteristics of a nonwoven material as air permeability, hygroscopicity increase, and a decrease in rigidity is observed. The study of the structure of the material (pore size) showed that the treatment with NLTP leads to a significant decrease in the size of large pores and an increase in the size of medium and small pores

Abstract: Moisture and water transport in clay bricks are essential contributing factors towards brick decay in buildings. Experimental work is reported comparing water absorption and porosity of handmade and solid fired clay bricks from Paraguay. Their respective porosities were estimated by gravimetric test and, their pore distribution, degree of anisotropy and morphology were examined by SEM. Although it was found that both samples have a common composition (XRD), a higher degree of porosity was found in handmade bricks, which also absorb water at a higher rate accelerating the decay process. Experimental data is reported on the exponential kinetics behavior of water absorption similar to the one observed in capillary tubes, but with an additional diffusive process. A phenomenological model is proposed for water absorption in both types of bricks which compared with the standard model of water absorption available in the literature, produces a better representation of the experimental data.

Abstract: The article provides the details on the influence of marine environment on textile materials. It justifies the aggressive components of marine environment in contact with clothing surface: sea salt and oil. Sea salt is an integral part of sea water and accumulates in the structure of clothing. Oil becomes a part of sea water in contingency situations at offshore oil and oil products production and transportation facilities. This causes a variation of the properties of textile materials that depend on the concentration of aggressive components in the structure of textile materials. Active concentration of aggressive components in the textile is defined based on its liquid absorption capacity. The article establishes the peculiarities of volume variation for different textile fibers interfacing with liquids. It identifies the structure of sea salt and chemical composition of oil that cause a variation of the properties of textile in contact with them. It was established that the presence of sea salt in humid environment contacting with the surface of special cotton based fabric causes reduction of capillarity in all material samples. It was established that the packages of materials based on fabrics with mixed fibers have crude oil permeation less than cotton surfaces of clothing. Meanwhile, use of thermal insulation, like Hollofiber together with such materials, reduces the level of clothing saturation with subject liquids. The article presents experimentally obtained data on sea water and oil permeation into special clothing materials.

Abstract: The Church of Asunción of Llíria (Valencia, Spain) is one of the best examples of the Valencian Baroque of the seventeenth century. This research is based on the study of the building from an urban, historical, and especially, a constructive view. The location of this particular church is unique because it is embedded in a mountain. First, some excavations were made into the mountain before the construction of the church started. Thus, there is a slope between the main entrance of the church and the rear. This research work provides the analysis of the ground humidity throughout the Ground Penetrating Radar (GPR) technique. We have analysed the subsoil of the whole church by various cuts or paths. Longitudinal and transversal measurements allowed us to produce a three-dimensional model of the land on which the church stands. We have also analysed the homogeneity or heterogeneity of the subsoil in each area and the presence of certain ground water routes. The rising moisture has been analysed on the walls and pillars of the church. To this end, a moisture analyser has been employed to monitor the moisture content over a period of six months. With this information, it was possible to identify points that are systematically more humid.

Abstract: Adobe (raw mud brick) is a non-conventional technology that awakens a wide interest in sustainability constructions. However is important to improve the physical properties to reduction its water absorption and capillarity. The stabilization of adobe with products that don`t harm the environment and improve these physical properties must be goal for studies. Then Dynasolo DS328^® known as synthetic termite saliva" is a chemical stabilizer produced in Brazil that can be a good option. This composition with vegetal oils is non-toxic, hydrophobic and has cohesive properties. The product is a high-concentrated liquid, water soluble and non-flammable. Therefore, this research aimed to compared the synthetic termite saliva" incorporation at four different concentrations: 1:2000; 1:1500; 1:1000 and 1:500 with adobes without stabilization. The reagent chosen was an aluminum sulfate at 1:5000 for all treatments. The adobe soil is a Red Latosol cambisol in natura and corrected to 50% fine sand fraction. The ideal moisture content is variable, ranging from 50% to 40% according DS328^® increase. Adobes were submitted to water absorption, capillarity and linear contraction field tests science-based. This research confirmed the cohesive properties of chemical stabilization with synthetic termite saliva". It improved density and reduced the water absorption, capillarity, mass loss and linear shrinkage. The better treatment was 1:500 concentration.