En toxicologie et écotoxicologie, l’imprégnation est le résultat du dosage d’une toxine ou d’un polluant (ou des métabolites de leur dégradation) dans l’organisme. Akin could have had some assistant or intern look it up in minutes via Google Scholar or PubMed, as a … Conclusion However, this method is not generally applicable because it requires the payload molecules to withstand a temperature above their melting point, and the viscosity must below enough to allow the payload to efficiently enter the pore structure. The science behind all of this is straightforward. impregnating definition: 1. present participle of impregnate 2. to cause something, usually a solid substance, to absorb…. The fact or process of imbuing or saturating with something; diffusion of some element, idea etc. impregnate meaning: 1. to cause something, usually a solid substance, to absorb something, usually a liquid: 2. to…. The length and capacity of the oven determines the maximum throughput of the process. The low-temperature impregnation method resulted in the high loading of TiO2 also with mesoporous silicate with interparticle porosity KIL-2 [101]. Extruded asbestos yarn had a smoother surface than spun yarn. The science behind all of this is straightforward. They are available in a number of forms, which can be coated. Resin pickup is directly related to roving tension, i.e., as the roving tension increases, the resin pickup decreases. To compensate for slack or dampening a tension peak resulting from acceleration or deceleration, it is often necessary to use a dancer roller or a torque device at least on the wet side of the impregnation bath. For most applications, roller impregnation is preferred. The advantage is that there are no rollers on which the filaments could coil up on. These manufacturing routes start with the impregnation of UHMWPE fiber bundles. Intimate mingling techniques reduce the impregnation (mass transfer) distance of the matrix into the fibre bed during processing, reducing consolidation pressures. This aids handling for non-isothermal processes where heating occurs in a first step followed by often automated transfer to the cool moulding tool, but inhibits the use of isothermal conversion processes because the material cannot be conformed to the tool in the cold material state. By using the guiding eye most patterns can be wound perfectly on three-axis machines and in many cases even on two-axis machines. impregnation: [ im″preg-na´shun ] 1. fertilization . Direct impregnation process chains (top: polymer extruded and placed on the mandrel; bottom: melted polymer is pressed through a heated impregnation unit). Impregnation The treatment of castings with a sealing medium to stop pressure leaks, such as soaking under pressure with or without prior evacuation and either with hot or cold application. Early 17th century (in the sense ‘fill’; earlier (Middle English) as impregnation): from late Latin impregnat- ‘made pregnant’, from the verb impregnare. Early 17th century (in the sense ‘fill’; earlier (Middle English) as impregnation): from late Latin impregnat- ‘made pregnant’, from the verb impregnare. The tissues, after fixation and dehydration process, are not sufficiently hard to cut into thin sections without a suitable support. The impregnation of fibre beds with thermoplastics is inherently more difficult than with equivalent processes for most thermosets owing to the high viscosity of thermoplastics at melt temperature. By incorporating TiO2 nanoparticles formed by the ACSG (acid-catalyzed sol-gel) method into SBA-15 as TiO2 pluggs instead of silicate pluggs, the growth of TiO2 nanoparticles is controlled and their size could be tuned to a few nanometers. Pressure cycling drives the dispersion into the pores. In the first case, for example shown by Henninger and Friedrich,32 the impregnation of fibers by the matrix is done directly at the winding head. This way of working often seems comfortable but is not always efficient. The starting distribution of fibres, matrix and porosity (defining the preconsolidation level) dominate the structure of aligned fibre materials, which fall into two principal classes (Fig. Direct impregnation thermoplastic winding processes have some advantages compared to winding technologies which use semi-finished products. The winding pattern fiber type and number of axes on the machine will influence the design of the guiding eye. Packing was produced by braiding and cloth by weaving from spun or extruded yarn. The dispersion may be diluted moderately with deionized water or substantially using a dilute aqueous solution of a nonionic surfactant such as Triton® X–100. From: New and Future Developments in Catalysis, 2013, C. SOHL, in Comprehensive Composite Materials, 2000. The process of fertilization involves a sperm fusing with an ovum. However, a similar difference was not observed with ibuprofen. Important in science, microtomes are used in microscopy, allowing for the preparation of samples for observation under transmitted light or electron radiation. You can have carbon black of different porosities which can be impregnated with multiple chemicals and catalysts. When it comes to optimizing the production speed and maintaining high quality it is often necessary to be able to modify any machine motion separately, especially in the turnaround areas. Impregnation meaning The act of making pregnant; fertilization. Flax and polyaramide are used to fabricate packings and gaskets. An amount of impregnation solution equal to the pore volume of the support is then mixed with the dry support and the solution is drawn into the support pores via capillary action. Impregnation (chemistry): To cause a material to be filled or soaked with something. Courtesy of COMAT Composite Materials GmbH, Germany. 2. The act of making pregnant; fertilization. That with which anything is impregnated. The low density of fibers and matrix lead to very high specific properties and make the PE/PE composites interesting for lightweight applications. To fertilize (an ovum, for example). All Rights Reserved. Looking for the abbreviation of Vacuum Pressure Impregnation? See more. However, the term is often used for any impregnation method. Manganese loading via the wet-impregnation method is reported additionally for zeolite ZSM-5 [87,88] also for mesoporous MCM-41 [89–93], and SBA-15 [94] using mainly manganese acetate or nitrate solutions as the manganese component. Especially when using roving with high Tex values or heavy tows, a good and consistent fiber spread on the impregnation roll is important. The main advantage of the impregnation method is that it is easy to control the amount of the drug that is loaded in the carrier. In the fiber direction the compressive strengths are low, but Young's moduli and tensile strengths are high. In this method, the loading solution is mixed with the mesoporous material and then the solvent is evaporated (Fig. The final guide, the delivery eye, ensures that the rovings are aligned correctly for winding on the mandrel. through a medium or substance. The resin is then pressed into the roving while it passes over the rollers. Similar wet-impregnation methods are reported for SBA-15 [98] and SBA-15-like plugged hexagonally templated silica (PHTS). Chemical Engineering Science A theoretical study is presented dealing with the impregnation of one or two active species on a porous support, in order to predict the internal concentration as a function of the process parameters. Dictionary entry overview: What does impregnation mean? The loading can be performed manually in a general laboratory dish, or in a rotavapor, fluidized bed or spray dryer (Limnell et al., 2011; Shen et al., 2010; Takeuchi et al., 2005). The titanium loading via wet-impregnation method is reported for mesoporous silicate [97] prepared from sodium silicate as a cheap silicate precursor and impregnated with titanium oxychloride (TiOCl2) following thermal treatment at 873–1273 K for 5 h. The wet-impregnation method is also used for the functionalization of MCM-41 using Ti(OEt)4 dissolved in toluene [77a] following thermal treatment at 873 K for 6 h [77b]. These are discussed in section 6.3. The conclusion at which he arrives is that the pollen is not in all flowering plants necessary for impregnation, for fertile seeds can be produced without its influence. A good universal guiding eye is the “adjustable donut” (Figure 9). Because of their good tensile strength and further expected positive properties, e.g., high energy absorption capacity, biocompatibility, and chemical resistance, PE/PE composites are interesting for special applications, e.g., ballistic protection or as implant materials for artificial joints. Human fertilization is the union of a human egg and sperm, occurring in the ampulla of the fallopian tube. In the case of glass fiber, polished hard chrome or ceramic performs well, whereas carbon fiber will produce less fuzz on a “rougher” surface, i.e., sandblasted steel plated with hard chrome (Mitsubishi Chemical Corporation) (Figure 8). through a medium or substance. We use cookies to help provide and enhance our service and tailor content and ads. Impregnation has traditionally been used to load catalytic species into porous materials, but it is also suitable for loading porous materials for biomedical applications (Campanati et al., 2003; Mellaerts et al., 2008).
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