Ultra-stabilization

We have recently developed and obtained a patent for an ultra-stabilized high expansion foam (5 ) with expansion and drainage characteristics as shown in Table VI, using a polymeric additive for stabilization without harming expansion. 

Deactivation and the Role of Extraframework Aluminum in the Reactions of 2-Methylpentane on Ultra-Stabilized MY Zeolite... 

Dealumination and ultra-stabilization of zeolites through high temperature thermal treatment and hydrothermal treatment. 

Since the Si—O bond length (1.66 A) is shorter than that (1.75 A) of Al—O, the crystal lattice of zeolites is shrunken and the structure is stabilized after dealumination and silicon enrichment, as confirmed as follows. Of course, unavoidably there exist silicon-deficient hydroxyl nests after both dealumination and ultra-stabilization, and some mesopores will be generated in the USY framework. 

The structures and properties of heteroatom zeolites vary due to the introduction of heteroatoms in the zeolite frameworks. When treated in high-temperature water vapor, zeolites Y, mordenite, and ZSM-5 are dealuminated to be ultra-stabilized, whereas heteroatom zeolites undergo demetallation that is, the heteroatoms are removed from the frameworks to form extraframework species, and the resulting zeolites become catalytically active for special reactions. For instance, when treated in water vapor at... 

Anotlier standard metliod is to use a (high-speed) centrifuge to sediment tire colloids, replace tire supernatant and redisperse tire particles. Provided tire particles are well stabilized in tire solvent, tliis allows for a rigorous purification. Larger objects, such as particle aggregates, can be fractionated off because tliey settle first. A tliird metliod is (ultra)filtration, whereby larger impurities can be retained, particularly using membrane filters witli accurately defined pore sizes. 

In eatalytie eombustion of a fuel/air mixture the fuel reaets on the surfaee of the eatalyst by a heterogeneous meehanism. The eatalyst ean stabilize the eombustion of ultra-lean fuel/air mixtures with adiabatie eombustion temperatures below 1500°C. Thus, the gas temperature will remain below 1500 °C and very little thermal NO will be formed, as ean be seen in Figure 10-21. However, the observed reduetion in NOx in eatalytie eombustors is mueh greater than that expeeted from the lower eombustion temperature. The reaetion on the eatalytie surfaee apparently produees no NOx direetly, although some NOx may be produeed by homogeneous reaetions in the gas phase initiated by the eatalyst. 

Since acetal resins are degraded by ultra violet light, additives may be included to improve the resistance of the polymer. Carbon black is effective but as in the case of polyethylene it must be well dispersed in the polymer. The finer the particle size the better the ultra violet stability of the polymer but the poorer the heat stability. About 1.5% is generally recommended. For white compounds and those with pastel colours titanium dioxide is as good in polyacetals as most transparent ultraviolet absorbers, such as the benzophenone derivatives and other materials discussed in Chapter 7. Such ultraviolet absorbers may be used for compounds that are neither black, white nor pastel shade in colour. 

Weathering. This generally occurs as a result of the combined effect of water absorption and exposure to ultra-violet radiation (u-v). Absorption of water can have a plasticizing action on plastics which increases flexibility but ultimately (on elimination of the water) results in embrittlement, while u-v causes breakdown of the bonds in the polymer chain. The result is general deterioration of physical properties. A loss of colour or clarity (or both) may also occur. Absorption of water reduces dimensional stability of moulded articles. Most thermoplastics, in particular cellulose derivatives, are affected, and also polyethylene, PVC, and nylons. 

Miscibility or compatibility provided by the compatibilizer or TLCP itself can affect the dimensional stability of in situ composites. The feature of ultra-high modulus and low viscosity melt of a nematic liquid crystalline polymer is suitable to induce greater dimensional stability in the composites. For drawn amorphous polymers, if the formed articles are exposed to sufficiently high temperatures, the extended chains are retracted by the entropic driving force of the stretched backbone, similar to the contraction of the stretched rubber network [61,62]. The presence of filler in the extruded articles significantly reduces the total extent of recoil. This can be attributed to the orientation of the fibers in the direction of drawing, which may act as a constraint for a certain amount of polymeric material surrounding them. 

The study of ultra-thin Fe thin films on Cu(OOl) substrate has attracted a lot of interest in the past. This is due to the abundance of interesting phenomena associated with this system. Due to the small epitaxial misfit a good layer by layer growth is expected stabilizing the film in a structure related to the fee phase of bulk Fe which is otherwise unstable at low temperatures It also become a test system for magnetic measurements. 

Ultra Stable Y is a hydrothermally treated Y-faujasite which has a unit cell. size at or below 24.50 °A and exhibits superior hydrothermal stability over Soda Y faujasite. 

Recently, room temperature ionic liquids (RT-ILs) have attracted much attention for their excellent properties, e.g., wide temperature range of liquid phase, ultra-low vapor pressure, chemical stability, potential as green solvents, and high heat capacities [64,65]. These properties make them good candidates for the use in many fields, such as thermal storage [66], electrochemical applications, homogeneous catalysis [67], dye sensitized solar cells [68], and lubricants [69,70]. 

Carrots (Boleo) were peeled by 2% NaOH at 88-96°C for 4 minutes, minced by a meat mincer (2 mm) and homogenised for 2 minutes by an ULTRA-TURRAX T25 homogenizer (from Jahne Kunkel). The carrot mash was preheated to 45°C (20 minutes) before the enzyme preparations, 25 mg enzyme protein/kg mash, were added. The enzymes were dissolved in water to give a dilution of 5% (v/v) of the carrot mash. The mash was incubated at 45°C under stirring (60 rpm) for 2 hours, before the enzymes were inactivated at 86°C for 5 minutes in a microwave oven. Finally the purees were homogenised for 1 minute by ULTRA TURRAX. The viscosity of the puree was measured by a BROOKFIELD viscosimeter Model DV-n + with spindle A from HELIPATH SPINDLE SET at 2.5 rpm thermosta-ted at 50°C. The stability of the puree was measured as the sediment (in %) after centrifugation in 10 ml tube a 1660 x g for 10 minutes. 

RG-lyase was purified from Pectinex Ultra SP-L, produced by Aspergillus aculeatus, using anion- and cation-exchange chromatography. The purified RG-lyase differed from RG-hydrolase in pi and pH optimum and stability (Table I). 

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