Showing papers on "Vapours published in 1989"

Investigation of light emission from a parallel-plate avalanche chamber filled with noble gases and with TEA, TMAE, and H2O vapours at atmospheric pressure

Abstract: The light emission from avalanches in parallel-plate chambers, filled with noble gases and with TEA, TMAE, and H2O vapours at a total pressure p = 1 atm under the condition of low gas gain, has been investigated. Three important results have been obtained. 1. (1)|At partial pressures of more than a few Torr, and for a given charge gain, the light output from TEA, TMAE, and H2O in the spectral region 200–700 nm is much higher than from all other common quenching gases. 2. (2)|For these vapours, the ratio of light to charge is independent of their concentration when their partial pressure is more than a few Torr. 3. (3)|The best energy resolution achieved with the light-emitting chamber is ∼18% for 5.9 keV. Qualitative models explaining these results are given.

Superconductivity and the structure of YBa2Cu3O6 ceramics and single crystals treated in halogen vapours

Abstract: Dielectric ceramic and single crystal samples of YBa 2 Cu 3 O 6 were treated in halogen vapours (Cl, Br, I). After halogenation the transition to the superconducting state was observed at 90, 85 and 55 K, respectively.

Method and apparatus for the heating of wood or other materials sensitive to dehydration and heat

Abstract: The invention relates to a method for the quick and careful heating of wood or other materials which are sensitive to dehydration and heat damage. The heating is effected by placing the material in a chamber from which the air is completely evacuated prior to the heating phase. The chamber is then filled with saturated water vapours at a temperature which does not significantly exceed the temperature of the material which is required to be heated. The heating takes place by the saturated water vapours penetrating the spaces between the individual material parts. Here, the vapours condense on the surface of the material, whereby the material is heated. Among other things, the method can be used with advantage for the fixation of a number of impregnation agents in wood and for the drying of wood. There is also revealed an apparatus for use in the execution of the invention.

Dyes of the triphenylmethane type as sensor materials for solvent vapours

Abstract: The formation of highly coloured trityl ions from substituted phthalides can be utilized for the detection of solvent vapours in the air down to nearly ten ppm. These optochemical sensor materials were optimized with respect to their sensitivity, stability, linearity of the response and exclusion of the humidity influence. For this purpose the 4,4′,4″-substituents at the aromatic rings of the dyes must yield an appropriate carbenium ion stability. Thus even small amounts of absorbed solvent vapours lead to the reduction of the dye concentration in the sensor layers. The largest sensitivity can be achieved by applying dyes with two — N(CH3)2 substituents or, instead of one dimethylamino group, the — OCH3 group at the aryl rings. Further improvements to reduce the sensor response to moisture were possible by introducing into the phthalides large aromatic ring systems with a hydrophobic behaviour such as indolyl.

GC-MS Analysis of Organic Vapours Emitted from Polyurethane Foam Insulation

Abstract: The vapours emitted by rigid polyurethane foam at 40° and 80° in dry and in humid (90% RH) air were trapped with a Tenax TA sampling tube and, after thermal desorption, analyzed by high resolution gas chromatography – mass spectrometry. The chromatograms obtained demonstrate a certain characteristic pattern. The qualitative composition of the effluent mixture is basically independent of both temperature and humidity of the foam. Over seventy compounds were identified as polyurethane foam off-gases. Among them the most numerous are hydrocarbons. The most abundant is the blowing agent, trichlorofluoromethane. The most interesting are cyclic acetals, aldehydes, cyclic ethers, alcohols, chloroform and chlorobenzene. The headspace concentration of the majority of them is below 10mg/m3, there are, however, several compounds with the concentration exceeding 100mg/m3.

Interaction between glasses and alkali metal vapours

Abstract: The processes of interaction between silica glass, borosilicate glasses and sodium vapour or lithium vapour at elevated temperatures (300–700°C) have been studied. The change in the glass optical properties is quite different depending on chemical composition, the structure of glasses investigated and their high-temperature treatment conditions. Two established effects after glass treatment in alkaline vapours have been studied: one of them is characterized by a decrease of the absorption band of electrically melted silica glass at 5.0 eV and the second by UV bleaching in the optical spectra of some aluminoborosilicate glasses. It has been found that these effects are closely connected with the diffusion of alkali metals into the glass surface; the depth of sodium penetration in silica glass at temperatures in the range 300–700°C is 10–20 μm. In the specific experiments it has been proven that both effects are present in the bulk of the glass samples treated. For borosilicate glasses, bleached in UV after treatment in sodium and lithium vapours, the UV transmission increases and the UV absorption edge shifts to shorter wavelengths. The forbidden gap of these glasses changes its value from (3.3 ± 0.1) to (4.4 ± 0.1) eV. In the present paper a likely mechanism is proposed for the interaction between glasses and alkali metal vapours.

Process for curing and conditioning glass surfaces

Abstract: In order to increase the scratch resistance of glass surfaces and to achieve hydrophobicity, the glass surfaces are coated at temperatures between 580@C and 680@C with heated, steam-containing room air which has been admixed with vapours of solvents and of organic compounds of titanium, tin and/or silicon. The process allows environmentally friendly working without the formation of hydrochloric acid vapours and is also particularly suitable for thin glasses. Apparatuses for carrying out the process are described, including an apparatus for increasing the scratch resistance of curved safety glasses.

Process and adsorbent for removing iodine and/or organic iodine compounds from gases and/or vapours

Abstract: The invention relates to a process for the rapid and virtually complete removal of iodine and/or organic iodine compounds having a low number of carbon atoms from gases and/or vapours using zeolite X containing heavy metals. The object underlying the invention is to create a process and an adsorbent usable herefor which avoids the disadvantages of the known adsorbents and processes operated therewith and ensures a rapid virtually complete removal of iodine and/or organic iodine compounds having a low number of carbon atoms from gases and/or vapours from nuclear plants under various, rapidly changing and possibly extreme operating conditions, e.g. during or after an accident. The object is achieved according to the invention by the gases and/or vapours containing iodine and/or iodine compounds being passed through a layer of binder-free molecular sieve granules which have been exchanged with silver and at least one further heavy metal.

Process for the production of silicon carbide, having a high specific surface, for catalyst substrate

Abstract: The invention relates to a process for the production of fine silicon carbide grains, having a submicronic average size and a specific surface at least equal to 100 m g , intended especially to be used as a catalyst support for petrochemistry, this process consisting in reacting silicon monoxide SiO vapours with carbon According to this process: - SiO vapours are generated in a first reaction region by heating an SiO2 + Si mixture, at a temperature between 1100 and 1400 DEG C, at a pressure between 01 and 15 hPa; - the SiO vapours are brought into contact, in a second reaction region, with the reactive carbon, in the divided state, with a specific surface at least equal to 200 m g , at a temperature between 1100 and 1400 DEG C

Process for removal of iodine and iodine compounds from gases and vapours with silver containing zeolite x

Abstract: Process for rapid and almost complete removal of iodine and/or organic iodine compounds having a low number of carbon atoms from gases and/or vapours, in which the gases or vapours containing iodine and/or iodine compounds are passed through a layer of binder-free silver-exchanged molecular sieve granules of the structural type of faujasite.

Trace analysis of gallium arsenide by selective evaporation of the matrix with bromine vapours

Abstract: Gallium arsenide samples are analyzed by graphite furnace AAS after the selective evaporation of the matrix elements as bromides with bromine vapours in a simple apparatus. The evaporation step is carried out at 280–300 ° C and it is accomplished for 0.5 g sample within 1 h. Reproducibilities of 5 to 20% were obtained. Detection limits (3 s, in ng/g) are 20 (Fe), 5.0 (Ca), 3.0 (Mg), 2.0 (Ni, Cu), 1.0 (Al), 0.5 (Pb, Co), 0.2 (Mn, Cr).

Sensor material for the measurement of the partial pressure of gases or vapours, and gas sensor

Abstract: According to the invention, a sensor material (16) which consists at least partially of at least one hydrophobic metal complex whose ion mobility or ion concentration or optical properties are altered by exposure to gas is provided as a sensor for gases or vapours, in particular for solvent vapours. Said metal complexes can be applied to suitable electrode arrangements or carriers and form a sensor system for gases and vapours when combined with simple measuring bridges or photometers. In further embodiments, the sensor may also be designed as a field-effect transistor, as an MOS diode or as a hybrid structure.

Process for preventing emissions from hot zinc ashes

Abstract: In the recovery of zinc metal from zinc-coating ashes, vapours are formed which exceed the permissible concentration in the surrounding air. Treatment of the hot ash with water or steam prevents these emissions or significantly reduces them.

Method and apparatus for the recovery of organic vapours from gases

Abstract: A method and apparatus for the recovery of organic vapours from gases, in particular of gasoline vapours, is proposed, wherein the laden gases or gasoline vapours are scrubbed in a downward-flow cooler in co-current of gas and scrubbing fluid in a scrubber, the cooling of the gas/scrubbing fluid mixture taking place in counter-current in the scrubber.

Method and apparatus for spraying and atomising liquids

Abstract: The method and the apparatus for spraying and atomising liquid substances is used, in particular, for the production of vapours for inhalation purposes. The liquid substance to be sprayed is so highly compressed that its volume is reduced and it is then released explosively into the normal atmosphere. As a result of the high internal pressure, the liquid substance is broken down into very small particles.

Effect of Humidity and Electronic Packaging Exhalates on the Performance of some Active and Passive Components used in an Electronic Equipment

Abstract: The performance of some commercial P-N Junction diodes, some ceramic capacitors and some resistors has been tested under moisture (RH 60% to 95%) and various exhalate vapours (HCl, HNO3., HCOOH, CH3 COOH, NH3 and SO2) which are generally released by the electronic packaging materials. The ideality factor of the diode changes after exposure, the change being more at higher exposure times. The organic acid vapours degrade the devices the most. Silicon diodes, in general, are found to be less sensitive to the humidity and exhalate vapours as compared to Germanium and Indium Antimonide diodes. The presence of oxide layer on the surface of silicon diodes may be responsible for the smaller degradation effect.

A comparative study of the suitability of sircar's and BET isotherms to study the adsorption of vapours on non-porous adsorbents

Abstract: A comparative study is reported of the suitability of the BET and Sircar equations for the analysis of the adsorption isotherms of vapours on non-porous solids, by applying both equations to experimental data reported in the literature corresponding to the adsorption of nitrogen at 77 K on a non-porous carbon-coated silica. It is concluded that Sircar's method, despite its greater mathematical complexity, does not provide better precision in determining the parameters of the equation. In addition, the monolayer capacity values are very different in both cases

Process for liquefying coal

Abstract: In a process for liquefying coal under elevated pressure and at elevated temperature in a reaction zone, it is proposed to feed the reaction product leaving the reaction zone to a coking zone and to cool the gases and vapours arising there, predominantly distillate oil vapours, preferably in direct exchange with the fresh coal paste. The gases and vapours not condensed in this heat exchange are taken off from the plant as end product. By means of the proposed procedure, the oil production is partially displaced from the reaction zone to the coking zone, so that the reaction zone can be operated under a low pressure. Furthermore, a major part of the quantity of exothermic heat generated in the liquefaction reactions can be recycled to the process by the direct heat exchange of the product vapours with the fresh coal paste.