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Technical Application

Spider silk has also a potential to be employed in technical applications such as micromechanical and electronic set-ups. Recombinant silk proteins can self-assemble into nanofibrils, which can be decorated with inorganic particles such as metals or quantum dots [67, 124, 130-136]. Such decorated silk fibrils could be used as nanowires [137, 138] or surface coatings [139, 140]. In addition, in an approach similar to soft Hthography, pouring the silk solution on to a patterned substrate enables conformal replication of substrate features down to a [Pg.202]

The biochemical functionality of proteins, enzymes, and small organics embedded in hardened silk optics has recently been reported [143]. Devices were fabricated by simply mixing an organic indicator (phenol red) and an enzyme (horseradish peroxidase) or a small protein (hemoglobin) into the water-based fibroin solution [144]. The solution was then cast on a holographic diffraction-grating master [Pg.203]

Sperling, L.H. (2005) Mechanical behavior of polymers, in Introduction to Physical Polymer Science, 4th edn (ed. J.W., Sons), John Wiley Sons, Inc., Hoboken, NJ. [Pg.205]

Dunaway, D.L, Kerkam, K., and Case, S.T. (1994) in Silk Polymers. Materials Science and Biotechnology, Vol. 544 (eds D., Kaplan, W.W., Wade, B., Farmer, and C., Viney), American Chemical Society, Washington, DC, pp. 120-136. [Pg.205]

Systems Influence of Micro and Molecular Structure, Eindhoven University of Technology. [Pg.205]

So far, the homologation reaction has reached only the pilot-plant scale [58, 61], Little information is available about the reaction in continuous operation. The only cobalt-catalyzed continuously conducted reaction led to a mixture of 20 different products. The yield of ethanol is low (16 mol%) [59]. By activation with iodine and variation of the space-velocity, the overall yield has been improved and the ratio of acetaldehyde/ethanol could be varied between 13 18 and 2 17 [60]. BP has described continuous homologation with the Co/l/PPh3 catalyst system. The yield of ethanol reached only 25 mol % [11]. Semicontinuous work on the homologation reaction has been reported by the former Ruhrchemie AG [61]. [Pg.1042]

Seven of the most convincing discontinuously developed catalyst systems were recycled nine times and conversion and selectivity were noted (cf. Table 2). The catalyst compounds were separated by a special distillation unit under CO/H2 [Pg.1042]

Catalyst system Conversion [mol %] of methanol Selectivity [mol %] to ethanol  [Pg.1044]

Enzymes provide catalytic pathways which are often superior to non-enzymic routes. The advantage of enzymes can overcome their disadvantages as relatively unstable species which workbest in aqueous solution. In synthetic processes, the selectivity of the enzyme-catalysed process is not approached by chemical catalysis particularly regarding the enantioselective synthesis of chiral molecules. Furthermore, protective group chemistry is often not required in enzyme-catalysed reactions. [Pg.312]

Enzyme catalysis can be employed to detect concentrations of metabolites such as blood sugar, urea, uric acid or ATP. The metabolite is often best reacted with a co-enzyme such as NADPH or pyridoxal phosphate which changes its UV-vis absorption spectrum upon reaction. [Pg.312]

Inhibition can be reversible when it simply complexes at the active site preventing further catalysis. The active enzyme under these conditions can be recovered by dialysis. Another form of inhibition is the irreversible type where the active enzyme cannot be recovered by dialysis. A variant of this type of inhibition is suicide inhibition a substrate of the enzyme reacts at the active site to yield an irreversible inhibitor which then reacts directly with groups at the active site [18]. A technique, in situ click chemistry , is related to that of suicide inhibition and involves click chemistry components which complex at the active site of an enzyme and combine to form femtomolar inhibitors. The technique can be used to synthesise inhibitors or by selection from a library of click chemistry components to search structure space of the inhibitor for the drug target [ 19]. [Pg.312]

The technical applications referred to above can be studied using standard techniques to be described below these differ in kind from those used in the study of catalysis by small molecules. [Pg.312]


X-ray tubes are used in a broad variety of technical applications the classical application certainly is the radiographic inspection. For the penetration of high-Z materials, relatively high power is required. This lead to the development of X-ray tubes for laboratory and field use of voltages up to 450 kV and cp power up to 4,5 kW. Because of design, performance and reliability reasons, most of these maximum power stationary anode tubes are today made in metal-ceramic technology. [Pg.535]

A brief description of a low-density non-equilibrium plasma is given followed by a review of its characteristic features and of tire relevant collisionprocesses in tire plasma. Principles for tire generation of plasmas in teclmical devices are discussed and examples of important plasma chemical processes and tlieir technical applications are presented. [Pg.2795]

K. H. Saunders, The Aromatic Dia -Compounds and Their Technical Applications, Edward Arnold Co., London, 1949. [Pg.256]

M. Sotton, Index 81 Congress Papers, JYonwovens For Technical Applications, 1—15 (May 1981). [Pg.465]

Considerable alterations have been made in the chapters concerned with technical applications which are the result of advances in electrochemical corrosion protection in general practice. Here also, abbreviation and omission of less relevant parts of the older editions have had to be made to create space for more recent information. Recent applications in the chemical industry have necessitated a complete rewriting of the industrial chapter. A new chapter is included on the cathodic protection of steel reinforcement in concrete. [Pg.580]

The processes of cathodic protection can be scientifically explained far more concisely than many other protective systems. Corrosion of metals in aqueous solutions or in the soil is principally an electrolytic process controlled by an electric tension, i.e., the potential of a metal in an electrolytic solution. According to the laws of electrochemistry, the reaction tendency and the rate of reaction will decrease with reducing potential. Although these relationships have been known for more than a century and although cathodic protection has been practiced in isolated cases for a long time, it required an extended period for its technical application on a wider scale. This may have been because cathodic protection used to appear curious and strange, and the electrical engineering requirements hindered its practical application. The practice of cathodic protection is indeed more complex than its theoretical base. [Pg.582]

The discussion of acylation reactions in this chapter is focused on fluonnated carboxylic acid derivatives and their use to build up new fluorine-containing molecules of a general preparative interest Fifteen years ago, fluonnated carboxylic acids and their derivatives were used mainly for technical applications [/] Since then, an ever growing interest for selectively fluonnated molecules for biological applications [2, 3, 4, 5] has challenged many chemists to use bulk chemicals such as tnfluoroacetic acid and chlorodifluoroacetic acid as starting materials for the solution of the inherent synthetic problems [d, 7,, 9]... [Pg.525]

The preparative chemistry and technical applications of the halogen oxoacids and their salts have been actively pursued and developed for over two centuries (p. 790) and can now be very satisfactorily systematized in terms of general... [Pg.853]

In the meantime, we believe that the best prediction of the toxicity of an ionic liquid of type [cation] [anion] can be derived from the often well known toxicity data for the salts [cation]Cl and Na[anion]. Since almost all chemistry in nature takes place in aqueous media, the ions of the ionic liquid can be assumed to be present in dissociated form. Therefore, a reliable prediction of ionic liquids HSE data should be possible from a combination of the loiown effects of the alkali metal and chloride salts. Already from these, very preliminary, studies, it is clear that HSE considerations will be an important criterion in selection and exclusion of specific ionic liquid candidates for future large-scale, technical applications. [Pg.30]

Without a doubt, tetrafluoroborate and hexafluorophosphate ionic liquids have shortcomings for larger-scale technical application. The relatively high cost of their anions, their insufficient stability to hydrolysis for long-term application in contact with water (formation of corrosive and toxic HF during hydrolysis ), and problems related to their disposal have to be mentioned here. New families of ionic liquid that should meet industrial requirements in a much better way are therefore being developed. FFowever, these new systems will probably be protected by state of matter patents. [Pg.32]

I. SURVEY OF TECHNICAL APPLICATIONS OF NATURAL FIBER COMPOSITES... [Pg.787]

Today the renaissance of these materials as reinforcing fibers in technical applications is taking place mainly... [Pg.787]

The basic demand for technical application of these fibers is a defined quality, e.g., according to a specification sheet. These qualities have to be available for the... [Pg.787]

Presently, the demand for plant fibers for technical applications can be partially met (Table 1). [Pg.789]

An example by Olmstead [213] illustrates a limitation in the use of this effect for technical applications. Figure 15 shows a large conductivity increase at low concentrations upon addition of the ligand hexamethyltriethylenetetramine (HMTT) to Lil/DIOX which, however, decreases at increasing salt concentration in the technically interesting concentration range. [Pg.489]

Investigations of silicon-metal systems are of fundamental interest, since stable coordination compounds with low valent silicon are still rare [64], and furthermore, silicon transition-metal complexes have a high potential for technical applications. For instance, coordination compounds of Ti, Zr, and Hf are effective catalysts for the polymerization of silanes to oligomeric chain-silanes. The mechanism of this polymerization reaction has not yet been fully elucidated, but silylene complexes as intermediates have been the subject of discussion. Polysilanes find wide use in important applications, e.g., as preceramics [65-67] or as photoresists [68-83],... [Pg.4]

In the following pages I have endeavoured to deduce the principles of Thermodynamics in the simplest possible manner from the two fundamental laws, and to illustrate their applicability by means of a selection of examples. In making the latter, I have had in view more especially the requirements of students of Physical Chemistry, t6 whom the work is addressed. For this reason chemical problems receive the main consideration, and other branches are either treated briefly, or (as in the case of the technical application to steam and internal combustion engines, the theories of radiation, elasticity, etc.) are not included at all. [Pg.561]

In this external contractor role, water treatment companies providing technical application and problem solving services are required to possess some general design component and process operating knowledge... [Pg.994]

Poly(/)-phenylenctcrcphthalamiclc) forms a liquid crystalline solution and can be spun into a fiber with a very high orientation these fibers have excellent tensile and thermal properties. These high-modulus fibers are suitable as reinforcing materials in technical applications. [Pg.137]

A second group of alkylpolyoxyalkylene carboxylates, mostly used in technical application such as cutting oils, are the alkylpolyoxypropylenepolyoxy-ethylene carboxymethylates with the structure ... [Pg.315]

The alkylphenolpolyether carboxylates are virtually only used in technical applications. The method of synthesis is in principle similar to that of the alkylpolyether carboxylates. [Pg.319]

For technical applications, the production of ester sulfonates from the (purified) sulfo fatty acids involves too much effort, especially because the relevant fatty acid esters can be produced directly from the triglycerides of fats and oils by transesterification. The only possible way to produce ester sulfonates is the sulfonation of fatty acid esters. [Pg.464]

Because there are never chain length pure surfactants in technical applications, the CMC of mixtures of different ester sulfonates is important. Fabry and Giesen showed that the CMC value of C16 a-methyl ester sulfonate is lower than the value of a C16/C18 a-ester sulfonate. There is the same tendency for C16 a-disalt and C16/C18 a-disalt. For the C16/C18 mixtures the ester group has no influence on the CMC. The methyl ester has nearly the same values as the ethyl and the /-propyl ester [59]. [Pg.474]

The reaction partner of maleic acid anhydride can be changed. Instead of a hydroxyl group a primary or secondary amine can be used. Either monoamides or diamides can be obtained. Simple sulfation as mentioned above closes the reaction series. The variety of sulfosuccinamates (monoamides) and sulfosuccinamides (diamides) is smaller than that of sulfosuccinates. An important use lies in the field of technical applications (Fig. 2). [Pg.503]

Emulsifiers are used in many technical applications. Emulsions of the oil-in-water and the water-in-oil type are produced on a large scale in the cosmetic industry. Other fields of employment are polymerization of monomers in emulsions and emulsification of oily and aqueous solutions in lubricants and cutting oils. In enhanced oil recovery dispersing of crude oil to emulsions or even microemulsions is the decisive step. [Pg.601]

The enormous efforts put into the basic research and development of conducting polymers are naturally related to hopes of feasible technical apphcations The starting point of this development was the discovery that PA can fimction as an active electrode in a rechargeable polymer battery. Since then, the prospects of technical application have grown considerably Apart from the battery electrode, conducting polymers are discussed as potential electrochromic displays... [Pg.29]

The field of modified electrodes spans a wide area of novel and promising research. The work dted in this article covers fundamental experimental aspects of electrochemistry such as the rate of electron transfer reactions and charge propagation within threedimensional arrays of redox centers and the distances over which electrons can be transferred in outer sphere redox reactions. Questions of polymer chemistry such as the study of permeability of membranes and the diffusion of ions and neutrals in solvent swollen polymers are accessible by new experimental techniques. There is hope of new solutions of macroscopic as well as microscopic electrochemical phenomena the selective and kinetically facile production of substances at square meters of modified electrodes and the detection of trace levels of substances in wastes or in biological material. Technical applications of electronic devices based on molecular chemistry, even those that mimic biological systems of impulse transmission appear feasible and the construction of organic polymer batteries and color displays is close to industrial use. [Pg.81]

There are a number of naturally occurring polymers which find technical application, including cellulose and its derivatives, starch, and rubber. In addition, a number of important biological materials, most notably the proteins, are made up of macromolecules. These will be considered briefly in the sections which follow. [Pg.18]


See other pages where Technical Application is mentioned: [Pg.2811]    [Pg.1126]    [Pg.418]    [Pg.503]    [Pg.228]    [Pg.8]    [Pg.1546]    [Pg.388]    [Pg.216]    [Pg.218]    [Pg.787]    [Pg.219]    [Pg.404]    [Pg.938]    [Pg.457]    [Pg.437]    [Pg.40]    [Pg.2]    [Pg.314]    [Pg.349]   
See also in sourсe #XX -- [ Pg.787 ]

See also in sourсe #XX -- [ Pg.191 , Pg.193 ]

See also in sourсe #XX -- [ Pg.16 ]




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