Abstract: An electrostatic speaker system including at least one electrostatic speaker element having a pair of stators and a diaphragm therebetween, each of the stators and the diaphragm having an least one electrically conductive portion. The conductive portion of the diaphragm is patterned as a mesh, which may include gaps, and a conforming layer overlying the conducting portion of the diaphragm and disposed so as to cover gaps in the mesh. A speaker drive circuit provides soft clipping of the audio input signal so that the audio signal applied between the diaphragm and the stators does not exceed the maximum acceptable level that can be applied between the diaphragm and the stators of at least one speaker element.

Abstract: An electrostatic speaker system including at least one electrostatic speaker element having a pair of stators and a diaphragm therebetween, each of the stators and the diaphragm having an least one electrically conductive portion. The conductive portion of the diaphragm is patterned as a mesh, which may include gaps, and a conforming layer overlying the conducting portion of the diaphragm and disposed so as to cover gaps in the mesh. A speaker drive circuit provides soft clipping of the audio input signal so that the audio signal applied between the diaphragm and the stators does not exceed the maximum acceptable level that can be applied between the diaphragm and the stators of at least one speaker element.

Abstract: 4,5-Disubstituted imidazole-2-carboxylic acids are prepared by reacting 4,5-disubstituted imidazoles with carbon dioxide under superatmospheric pressure at from 150.degree. to 300.degree. C. in the presence of a base.

Abstract: The soot obtained in the form of a soot-containing aqueous waste liquor in the course of synthesis gas manufacture is utilizable bya) mixing said liquor in a sewage sludge treatment plant with a sewage sludge to which organic flocculants are added as drainage aids with or without a further quantity of finely divided coal or ash,b) filtering this pretreated sludge mixture,c) incinerating the resulting filter cake andd) burying the ash in a sanitary landfill.

Abstract: Synthesis gases are prepared by partial autothermal oxidation of liquid fuels and/or solid fuels in the presence of oxygen or oxygen-containing gases with the addition of a temperature moderator, such as steam and/or CO.sub.2, in an empty reactor space without baffles, at from 1000.degree. to 1500.degree. C. under from 1 to 100 bar, the reactants fuel and oxygen-containing gas being fed separately to the reactor, by a process in which the steam or CO.sub.2 is fed in simultaneously with the feed of the fuel, and the steam is let down through one or more nozzles into the fuel steam directly before the orifice for the fuel, let-down being effected at from 30 to 250%, preferably from 80 to 140%, of the critical pressure ratio. An apparatus for carrying out the process is also described.

Abstract: Hexaarylbisimidazoles I ##STR1## where Ar.sup.1, Ar.sup.2 and Ar.sup.3 are each aryl, of which Ar.sup.2 and Ar.sup.3 can be linked to form an anellated ring system, are prepared by oxidizing the corresponding triarylimidazoles II in an aqueous/organic two-phase system in the presence of active amounts of an onium salt III.

Abstract: Carbon black and ash containing wastewaters from high-temperature processes in which the carbon black is present in an extremely finely divided and partly colloidal state are cleaned and disposed of by treatment with organic flocculants, predewatering of the flocculated suspension by gravity filtration and post-dewatering of the carbon black sludge by pressure filtration within the range from 0.5 to 15 bar in a process comprising adding sufficient calcium hydroxide to the wastewaters that the pH of an aqueous extract of the filter cake obtained is more than 11.8, preferably more than 12.0.

Abstract: 4(5)-nitroimidazole-5(4)-carboxylic acids are prepared by reacting an imidazole-4(5)-carboxylic acid with a mixture of sulfuric acid and nitric acid at not less than 80.degree. C., the water content of the reaction mixture at the beginning of the reaction being no higher than 5% by weight, based on the reaction mixture.

Abstract: Imidazole-4(5)-monocarboxylic acids and their salts or betaines are prepared by reacting an imidazole with carbon dioxide and an alkali metal carbonate, an alkali metal bicarbonate and/or an alkali metal hydroxide at from 140.degree. to 230.degree. C. and under from 2 to 350 bar and, if desired, then reacting the product with an acid.The imidazole-4(5)-monocarboxylic acids which can be prepared by the process of the invention are useful starting materials for the preparation of dyes, crop protection agents and drugs.

Abstract: 2-Alkyl-4,5-dihydroxymethyl-imidazoles of the formula ##STR1## where R is alkyl, are prepared by a process in which an imidazole of the formula ##STR2## is reacted with not less than 2 moles of formaldehyde in the presence of a base.

Abstract: Imidazole-4,5-dicarboxylic acid is prepared by a process in which imidazole is reacted with formaldehyde, and the reaction mixture is treated with nitric acid.

Abstract: 2-Imidazolines are prepared by reacting N,N'-diformyl-1,2-diamines in the gas phase at 200.degree.-350.degree. C., in the presence of certain amounts of an inert gas, over zinc oxide of a particular structure or over a mixture of this zinc oxide and aluminum oxide, as the catalyst.The 2-imidazolines obtainable by the process according to the invention are valuable starting materials for the preparation of dyes, crop protection agents and drugs.

Abstract: Imidazoles are prepared by reacting 2-imidazolines at from 250.degree. to 500.degree. C. in the presence of molybdenum oxide and nickel oxide and/or cobalt oxide and aluminum oxide, silicon dioxide and/or silicates as catalysts.The imidazoles obtainable by the process according to the invention are valuable starting materials for the preparation of dyes, crop protection agents, textile auxiliaries, catalysts for polyurethanes and epoxy resins, surfactants and drugs, for example the corresponding nitroimidazoles.

Abstract: A novel process for the preparation of 2-imidazolines by reacting 1,2-diamines with nitriles or carbonyl compounds in the gas phase at from 200.degree. to 450.degree. C. in the presence of an oxide or phosphate of a metal of group 3 or 4 of the periodic table and/or in the presence of silicon dioxide.The 2-imidazolines obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents and drugs.

Abstract: A process for the manufacture of 5-hydroxymethylimidazoles by reaction of an imidazole with formaldehyde or an oligomer of formaldehyde in aqueous hydrochloric acid solution containing from 5 to 18% by weight of hydrogen chloride, at from 80.degree. to 160.degree. C., if desired in a closed system under pressure, followed by isolation in the form of its hydrochloride of the 5-hydroxymethylimidazole obtained.

Abstract: N-substituted carboxylic acid amides are prepared by reacting cyano compounds with olefins and water in the presence of cation exchangers containing sulfonic acid groups. The end products I are starting materials for the preparation of dyes, pesticides, emulsifiers, dispersants, stabilizers, textile auxiliaries and printing assistants.

Abstract: 1-Hydroxymethylimidazoles which are unsubstituted or alkyl-substituted in the 2-position, their manufacture and their use as chemical intermediates, e.g. for other imidazole derivatives or for the drug cimetidine.

Abstract: 1-Hydroxymethylimidazoles which are unsubstituted or alkyl-substituted in the 2-position, their manufacture and their use as chemical intermediates, e.g. for other imidazole derivatives or for the drug cimetidine.