Plant modifications

Niskayuna Ordnance Modification Plant, Schenectady, NY Nebraska Ordnance Plant, Wahoo, Neb... 

The paint is available in several modifications. Planted surfaces may be matt or glossy, hydrophobic or hydrophilic impregnated widl surface layers may be porous or smooth. Gloss planting onto a smooth impregnated wall may be used when a wall is in contact with water or splashes water absorption will be zero. Matt hydrophobic paint prevents the infiltration of walls by salts, offers rain resistance and a permanent fresh appearance, and at the same time provides no obstacle for water vapor to penetrate the wall when outer-layer pores are not filled with paint and their surface is not hydrophobicized. Hydrophilic paint accelerates drying of the wall in damp or wet room interiors. 

Pfalz M, Mikkelsen MD, Bednarek P, Olsen CE, Halkier BA, Kroymann J (2011) Metabolic engineering in Nicotiana benthamiana reveals key enzyme functions in Arabidopsis indole glucosinolate modification. Plant Cell 23 716-729... 

However, if the total glycerolipid composition of a given membrane is rather stable, its fatty acid content is more susceptible to environmental variations or modifications. Plant membrane glycerollplds have been subjected to analyses with respect to proportions, distribution and pairing of fatty acids. The uniqueness of chloroplast membranes, with specific fatty acids such as 16 3 in some molecular species of IKDG and 16 lj. in PG, and their high level of unsaturation, has focused... 

It now appears that many hormones (e.g. glucagon and adrenaline) in both animals and plants exert their effects by, as a first step, decreasing or increasing cyclic AMP within the cell. This may possibly occur by modification of the activity of the enzyme AMP cyclase which generates cyclic AMP from ATP. 

As introduced in Section 14.2, bottlenecks in the process facilities can occur at many stages in a producing field life cycle. A process facility bottleneck is caused when any piece of equipment becomes overloaded and restricts throughput. In the early years of a development, production will often be restricted by the capacity of the processing facility to treat hydrocarbons. If the reservoir is performing better than expected it may pay to increase plant capacity. If, however, it is just a temporary production peak such a modification may not be worthwhile. 

Approximately 50—55% of the product from a coal-tar refinery is pitch and another 30% is creosote. The remaining 15—20% is the chemical oil, about half of which is naphthalene. Creosote is used as a feedstock for production of carbon black and as a wood preservative. Because of modifications to modem coking processes, tar acids such as phenol and cresyUc acids are contained in coal tar in lower quantity than in the past. To achieve economies of scale, these tar acids are removed from cmde coal tar with a caustic wash and sent to a central processing plant where materials from a number of refiners are combined for recovery. 

Textile dyes were, until the nineteenth century invention of aniline dyes, derived from biological sources plants or animals, eg, insects or, as in the case of the highly prized classical dyestuff Tyrian purple, a shellfish. Some of these natural dyes are so-caUed vat dyes, eg, indigo and Tyrian purple, in which a chemical modification after binding to the fiber results in the intended color. Some others are direct dyes, eg, walnut sheU and safflower, that can be apphed directly to the fiber. The majority, however, are mordant dyes a metal salt precipitated onto the fiber facUitates the binding of the dyestuff Aluminum, iron, and tin salts ate the most common historical mordants. The color of the dyed textile depends on the mordant used for example, cochineal is crimson when mordanted with aluminum, purple with iron, and scarlet with tin (see Dyes AND DYE INTERMEDIATES). 

A modification of the conventional soy protein isolate process has been investigated on a small pilot-plant scale. It is based on the absorption of water from the aqueous protein after extraction at pH 8.5 using temperature-sensitive polyisopyropylacrylamide gels, followed by spray drying to give a 96% protein isolate (111). 

Oxidation of methanol to formaldehyde with vanadium pentoxide catalyst was first patented in 1921 (90), followed in 1933 by a patent for an iron oxide—molybdenum oxide catalyst (91), which is stiU the choice in the 1990s. Catalysts are improved by modification with small amounts of other metal oxides (92), support on inert carriers (93), and methods of preparation (94,95) and activation (96). In 1952, the first commercial plant using an iron—molybdenum oxide catalyst was put into operation (97). It is estimated that 70% of the new formaldehyde installed capacity is the metal oxide process (98). 

Urea Process. In a further modification of the fundamental Raschig process, urea (qv) can be used in place of ammonia as the nitrogen source (114—116). This process has been operated commercially. Its principal advantage is low investment because the equipment is relatively simple. For low production levels, this process could be the most economical one. With the rapid growth in hydrazine production and increasing plant size, the urea process has lost importance, although it is reportedly being used, for example, in the People s RepubHc of China (PRC). 

The racemic acid is not a primary product of plant processes but is formed readily from the dextrorotatory acid by heating alone or with strong alkaU or strong acid. The methods by which such racemic compounds can be separated into the optically active modifications were devised by Pasteur and were apphed first to the racemic acid. Racemic acid crystallizes as the dihydrate triclinic prisms. It becomes anhydrous on drying at 110°C... 

Applications Research. Specialty chemical producers devote a larger share of their time and costs to appHcations research than do producers of most commodity chemicals. As noted earHer, the most successful specialty chemical producers have been those companies that ate able to respond quickly to customer needs and problems under the conditions found in the customer s plant. This entails having, at the specialty chemical plant, equipment and procedural knowledge which closely approximate those found among customers. Tests can then be mn and a solution to the problem or need may result. If successful, even in part, it can be brought to the customers and tried there. In practice, of course, each customer s plant has some variables which make a single answer or product quite unlikely. Fortunately, slight modifications by the suppHer will often solve the next customer s problem. 

Bacterial removal of sterol side chains is carried out by a stepwise P-oxidation, whereas the degradation of the perhydrocyclopentanophenanthrene nucleus is prevented by metaboHc inhibitors (54), chemical modification of the nucleus (55), or the use of bacterial mutants (11,56). P-Sitosterol [83-46-5] (10), a plant sterol, has been used as a raw material for the preparation of 4-androstene-3,17-dione [63-05-8] (13) and related compounds using selected mutants of the P-sitosterol-degrading bacteria (57) (Fig. 2). 

Analyses and experimental results used to assess the consequences of a severe potential accident have resulted in substantially reduced estimates of severe accident consequences. Comparing estimates made by the U.S. Atomic Energy Agency (27) in 1977 with those reported by the U.S. NRC (18,28) in 1990 shows that improved knowledge and plant modifications have reduced the cote damage frequency by a factor of 3—15, depending on reactor type. Additionally, the fractions of radioactive species that would be released are lower by a factor of 10—100,000, depending on the radioactive species. 

The design or substantial modification of a new plant or process, its subsequent constmction, and start-up represent a tremendous investment of time and money. The rewards are great if a significant improvement is realized the risks are also great if a costiy commercial plant fails to produce as expected. To reduce the degree of risk, lengthy and expensive research programs are often undertaken. 

The need for a pilot plant is a measure of the degree of uncertainty in developing a process from the research stage to a hiU commercial plant. A modification to a weU-known process may go directiy from basic research work to design of a commercial plant using this approach for a brand new process risks a significant failure. Hence, one or more intermediate size units are usually desirable to demonstrate process feasibiUty as well as to determine safe scale-up factors. 

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