Cellulose media

As we compare paper with thin-layer chromatography, we can see that paper sheets as such probably will be supplanted by thin-layer cellulose media. This means that the same immobile-mobile systems that are applied to paper can also be used for cellulose thin layer. The inorganic adsorbents do not appear to be very efficient for resolving highly polar compounds. When they are impregnated with immobile phases, ascension times are increased greatly because the capillaries are being... 

Supplementation of the raw substrate may be required in order to stimulate growth, induce enzyme synthesis, or prolong secondary metabolite production. Most traditional food fermentations do not require nutritional supplementation. In cellulosic media, supplements of 0.5% of glucose or cellobiose, 0.5% peptone, asparagine, or yeast extract are in use [75]. 

For larger applications, such as gas turbines, the need for clean filtered air is essential. Typically, these systems are compact and incorporate an all-welded steel construction. The filters are usually made from tmiformly pleated cellulose media, or spunbonded nonwovens, held in a steel frame, as illustrated in Figure 6.37, which shows a cutaway of an air intake system. In operation, dust-laden air enters through the weather louvres and passes through a series of filters (prefilter and fine filters). The cleaned air then moves into a clean air plenum and on into the turbine intake. 

Microcrystalline cellulose—coarse NF powder (Avicel PH 102), FMC. Microcrystalline cellulose—medium powder (Avicel PH101), FMC. Cornstarch NF powder, bolted, National Starch Chemical. 

Carboxymethyl Cellulose Medium-High Induced Medium Rigid Cyclic Side Chain Strong... 

Ruminococcus albus strain 7, (1), was grown on cellulose roll tubes according to the Hungate technique (2). Either Avicel (FMC Corporation, Marcus Hook, Pa.) or balled filter paper was used as the cellulose source. Three milliliters of melted cellulose-medium at 45 °C. in 16 X 150 mm. tubes were inoculated with the bacteria under a gas phase of 95% C02 and 5% H2. The tubes were subsequently stoppered and rolled in a tray of ice in order to form a film of agar medium around the... 

Figure 2. The kinetics of growth of organisms in CM-cellulose medium mixealy inoculated with Cellulomonas and Pseudomonas. A—Pseudomonas...

Figure 3. Differential count of the organisms during growth in CM-cellulose medium mixedly inoculated with Cellulomonas and Pseudomonas. The...

Sodium Carboxy Methyl Cellulose (Medium Viscosity) 0.5... 

International Rubber Study Group linoleic acid Life-Cycle Assessment Life-Cycle Inventory Life-Cycle Impact Assessment Lifestyle of Health and Sustainability methyl cellulose medium-density fibreboard... 

As shown in Table 3.2, 5% BTCA in the presence of 10% SHP and 0.1% TiO (as a cocatalyst) was nsed, and the addition of TiO as a cocatalyst further increased WRA by 58.5%. This was becanse both TiO and SHP accelerated the catalytic reaction throngh the formation of ester bonds between the cyclic anhydride ring and the hydroxyl gronp of cellulose. The improvement of WRA by the addition of TiO in the BTCA treatment was probably dne to the nniqne photocatalytic properties of TiO, which is a kind of N-type semicondnctor. The hydroxyl radical (-OH) and snperoxide anion (-0 -) formed may have acted as catalysts to accelerate the formation of anhydrides from poly (carboxylic) acids. Fnrthermore, the effect of hydroxyl radical (-OH) and superoxide anion (-O -) on the increase of charge localization of the sohd cellulose medium in which esterfication and cross linking occur may also have been significant. Therefore, WRAs of cotton fiber treated with 5% BTCA, 10% SHP, and 0.2% TiO further increased to 61.3% compared with those of the untreated cotton fabric. The increment was proportional to the increase of TiOj from 0.1 to 0.2% in the BTCA treatment bath (Lam et al., 2011). 

Rayon. Viscose rayon is obtained by reacting the hydroxy groups of cellulose with carbon disulfide in the presence of alkali to give xanthates. When this solution is poured (spun) into an acid medium, the reaction is reversed and the cellulose is regenerated (coagulated). 

Most cellulose acetate is manufactured by a solution process, ie, the cellulose acetate dissolves as it is produced. The cellulose is acetylated with acetic anhydride acetic acid is the solvent and sulfuric acid the catalyst. The latter can be present at 10—15 wt % based on cellulose (high catalyst process) or at ca 7 wt % (low catalyst process). In the second most common process, the solvent process, methylene chloride replaces the acetic acid as solvent, and perchloric acid is frequentiy the catalyst. There is also a seldom used heterogeneous process that employs an organic solvent as the medium, and the cellulose acetate produced never dissolves. More detailed information on these processes can be found in Reference 28. 

A common surface cartridge is the pleated paper constmction type, which allows larger filtration areas to be packed iato a small space. Oil filters ia the automobile iadustry are of this type. The paper is impregnated, for strength, with epoxy or polyurethane resia. Any other medium ia sheet form, similar to cellulose paper, such as wool, polypropylene, or glass may be used. 

Membrane modules have found extensive commercial appHcation in areas where medium purity hydrogen is required, as in ammonia purge streams (191). The first polymer membrane system was developed by Du Pont in the early 1970s. The membranes are typically made of aromatic polyaramide, polyimide, polysulfone, and cellulose acetate supported as spiral-wound hoUow-ftber modules (see Hollow-FIBERMEMBRANEs). 

Starting cellulose, prepared by deacetylation of commercial, medium viscosity cellulose acetate (40.4% acetyl content). 

Class B direct dyes have poor leveling power and exhaustion must be brought about by controlled salt addition. If these dyes are not taken up uniformly in the initial stages it is extremely difficult to correct the urdevelness. They are dyes that have medium—high affinity and poor diffusion. In their apphcation the cellulose is entered into a dyebath containing ordy dye. The salt is added gradually and portionwise as the temperature is increased and possibly the final additions made after the dyebath has come to the bod. 

Acetate fibers are dyed usually with disperse dyes specially synthesized for these fibers. They tend to have lower molecular size (low and medium energy dyes) and contain polar groups presumably to enhance the forces of attraction by hydrogen bonding with the numerous potential sites in the cellulose acetate polymer (see Fibers cellulose esters). Other dyes can be appHed to acetates such as acid dyes with selected solvents, and azoic or ingrain dyes can be apphed especially for black colorants. However thek use is very limited. 

Filter aids should have low bulk density to minimize settling and aid good distribution on a filter-medium surface that may not be horizontal. They should also be porous and capable of forming a porous cake to minimize flow resistance, and they must be chemically inert to the filtrate. These characteristics are all found in the two most popular commercial filter aids diatomaceous silica (also called diatomite, or diatomaceous earth), which is an almost pure silica prepared from deposits of diatom skeletons and expanded perhte, particles of puffed lava that are principally aluminum alkali siheate. Cellulosic fibers (ground wood pulp) are sometimes used when siliceous materials cannot be used but are much more compressible. The use of other less effective aids (e.g., carbon and gypsum) may be justified in special cases. Sometimes a combination or carbon and diatomaceous silica permits adsorption in addition to filter-aid performance. Various other materials, such as salt, fine sand, starch, and precipitated calcium carbonate, are employed in specific industries where they represent either waste material or inexpensive alternatives to conventional filter aids. 

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