Translucent membrane

PROP Extracted from the red algae Rhodopyceae. Unground in thin, translucent, membranous strips ground pale buff powder, Sol in boiling water insol in cold water and org solvs. 

Properties Thin, translucent membranous pieces or pale buff powder. Strongly hydrophilic, it absorbs 20 times its weight of cold water with swelling forms strong gels at approximately 40C. 

Hess, B. Oesterhelt, D. In Dynamics of Energy-Translucing Membranes ,... 

Due to the absence of a stabilising pressurisation in mechanically tensioned structures, another type of aerogel insulation is employed. This version is a fleece made of two-component fibres which is sprinkled with aerogel particles. This produces a flexible and pressure-resistant mat which has highly favourable insulating properties. This fleece can be used both in combination with transparent ETFE foils and with translucent membrane materials such as PTFE-coated, glass-fibre fabric - see Fig. 12.4. The... 

A. Plant Systems. A system of null potential voltammetry was developed for investigating the effects of biocides and surfactants on the transport properties of leaf epidermal membranes. These membranes were obtained by a procedure which was found suitable for a wide variety of plant species. A residual translucent membrane composed of epidermal cells and the associated cuticular surface was exposed by gently rubbing the abaxial surface of the leaf with a moistened cotton-tipped applicator until all of the green material was removed. In these studies advantage was taken of the... 

Figure 7.7 Experimental setup to study translucent membranes clamped between two bathing solutions by...

A very narrow light path must be used in order to ensure that closely adjacent bands are resolved. If the instrument measures transmitted light it is necessary to make the supporting membrane translucent. This can be done by either impregnating the strip with an oil with a high refractive index or, for... 

A similar approach is considered when evaluating the chorionic-allantoic membrane. The chorion should be fused to the allantois and should appear semi-translucent (allantois) and half-opaque/vascularized (chorion). Examples of abnormalities of this structure include separation between the chorionic and allantoic membranes, reduction in size, or blood pooled within the structure. 

With some experience, no staining of the membrane is necessary. When the PVDF membrane is illuminated with white light immediately after transfer, protein bands appear as white, opaque areas surrounded by translucent protein-free membrane. Taking care not to dry the membrane, a protein band to be eluted can be marked with a pencil. 

He stares at a membranous curtain of geometric shapes. A single eye sits in the center. Thin veins pulse on the translucent curtain. 

The plastic supports exposed approximately 3 mm2 of the membrane surface. Protein-containing solution (350 pi) was placed under the membrane in contact with it. This was the source solution. Air was excluded from the membrane s pores by soaking them in ethanol, and then water (double distilled in glass) prior to use. Bubbles were excluded from the chambers by carefully placing the membrane onto the surface of the liquid in the test chamber. Since the membranes are thin and translucent, the presence of even very tiny bubbles could be observed through the membranes with a dissecting microscope. The mix was stirred continuously with a magnetic stir bar. Buffer (30 yd of phosphate buffered saline,... 

Because of unfavorable sorption effects on paper that cause tailing, materials with lower adsorptivity were sought. Thus, cellulose acetate [35] and nitrocellulose [36,37] membranes were introduced. Cellulose acetate can be either prepared in the laboratory by treating cellulose with acetic anhydride, or it may be purchased from commercial sources. Cellulose acetate membranes are readily soluble in phenol, glacial acetic acid, dichloromethane and acetone. In part they can be solubilized in several solvent mixtures e.g., chloroform/ethanol (9 1 v/v). For detection (optical scanning) the foil can be made translucent by immersion in cottonseed oil, decalin, liquid paraffin or Whitemore oil 120. 

Although an exact explanation of the almost linear displacement in the sensitivity between these two systems is not yet available, the observations show that this difference is affected by the properties of the matrix. For example, among clear materials polycarbonate based membranes are not very effective for the broad band and UV exposures, probably because of the light absorption in the matrix. Tinted microcolumn membranes and translucent materials with interconnected pores produce even lower sensitivities. 

Already many lightweight membrane structures are in existence, and an increasing number of them are planned for the future, e.g. football stadium roofs. For such structures the combination of materials produces widely differing properties. Some projects are very cost-effective, while others are used for more expensive building constructions. Some constructions are of a temporary nature, some are erected at a fixed location some are required to be portable, while others may remain in place for decades. Textile roofs or walls may be open or closed according to the time of day or the position of the sun others stay fixed in one position. Some materials are required to have high translucency others may be designed for maximum insulation. 

PCV-coated aramid fabric is the strongest available membrane material and is typically used for high pressure air beam tubes which function as primary structures. PVC protects the aramid against UV radiation. Because there is no translucency, its application is limited to high load applications. 

Encasing constructions can be used with several membrane layers to form an intermediate space that can be filled with air or another insulating material, making U-values from 2.7 to 0.8 W/m K possible. U-values down to even 0.2 W/m can be obtained by using opaque, flexible mineral fibre fills or translucent insulating material, for example blister foils, as well as reflecting intermediate layers which are commonly used in space technology (ref LPS see Rg. 3.12). 

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