Abstract: Apparatus is disclosed for rapidly collecting aerosols containing solid particles and micro organisms, such as viruses and bacteria, from relatively large volumes of air and concentrating these particulates as samples in water. This apparatus operates under conditions conducive to preserving the integrity and viability of the collected micro organisms. Ambient air containing aerosols drawn into and through the collector's interior by an air mover, is mixed with very warm air saturated with moisture and then with cold air, to cause the resulting vapor mixture to become supersaturated. This supersaturated water vapor rapidly condenses onto the incoming aerosol particles to form droplets with particles at their centers. The airstream carrying these droplets enters a cloud of air ions produced by a corona generator or, alternately, by a radioactive source emitting alpha particles.

Abstract: Apparatus for drying flowing gas includes a generally cylindrical vessel having a gas inlet and a gas outlet, two perforated plates of different metals in contact with each other transverse the interior of the vessel, and a third perforated plate downstream from the two mutually contacting plates.

Abstract: A personal dust sampler hangs from a ribbon (10) attached to the user's clothing and requires no pump or power source. Dust in the air is captured by a charged PVC sheet (2) exposed at (2a) but framed by a metal foil (25) and surmounted by a metal conductor plate (6) parallel to the charged PVC sheet (2). The plate (6) is supported by conductive gridwork (3) removably attached by a flange (3) to a metal base (21). The dust captured is determined in a method by weighing or by measuring the charge loss of the PVC sheet (2).

Abstract: The apparatus is formed of a centrifugal force and Coriolis force generating device and a gas and liquid separation device. The centrifugal force and Coriolis force generating device gives high energy to supplied liquid by generating a spirally flowing air stream therein, to thereby ion-dissciate the liquid. Also, it provides energy necessary to micronize and activates the liquid drops with the centrifugal force and Coriolis force acted in the spirally flowing air stream. The activated liquid drops ionize oxygen particles at the gaseous side when electric doublets is oriented on the surface of the liquid drops, thereby causing groups of negative ions to be generated. The gas and liquid separation device separates the gas and liquid sent out from the centrifugal force and Coriolis force generating device and discharges air including negative ions into the atmosphere.

Abstract: A waste airstream decontamination unit has a series of grounded electrodes extending vertically from rotating shafts mounted transversely across a decontamination chamber. Corresponding upper and lower positive electrodes extend toward the rotating grounded electrodes in an angular relationship. Rotation of the shafts causes the charged electrodes to produce and sustain a repeating sequence of arcs which ionize and control the airborne contaminants which are passed through the chamber.

Abstract: A process for forming a direct positive image by developing, after imagewise exposure to an internal latent image type light-sensitive silver halide photographic material, with a surface developer for silver halide, which process comprises incorporating at least one fogging agent selected from hydrazine compounds, N-substituted cycloammonium salts and benzimidazole derivatives in combination with an amineborane compound into said light-sensitive silver halide photographic material, said surface developer and/or a treating bath used prior to the treatment by said surface developer.

Abstract: Positive images including color images are obtained by imagewise exposure and development of a material which comprises at least one light-sensitive silver halide emulsion layer which contains an unfogged direct-positive silver halide emulsion, when the development is carried out in the presence of a fogging agent of the formula ##STR1## wherein the symbols are defined as hereinafter. The fogging agent is preferably contained in a layer of the material and more preferably in the unfogged direct-positive silver halide emulsion layer. For the production of color instant images the material may also contain non-diffusible color providing compounds capable in their oxidized form of being split under alkaline photographic development conditions to release diffusible dyes.

Abstract: Disclosed herein are photothermogrpahic elements comprising stable free radical nitroxyl compounds. These compounds do not adversely affect the photographic properties of negative-working radiation sensitive emulsions and can be advantageously used in dry photothermographic processes to produce direct positive neutral or color images.

Abstract: This invention relates to color providing compounds useful as dye image-forming materials in color photographic processes. These compounds comprise a complete dye, i.e., a dye radical comprising the chromophoric system of a dye, such as, an azo, anthraquinone, azomethine or phthalocyanine dye and a cyclic moiety capable of undergoing cleavage in the presence of silver ion and/or soluble silver complex containing the group ##STR1## wherein said C atom common to said S and N atoms is a tetrahedral carbon atom possessing 4 single covalent bonds. Preferred compounds comprise the radical of an organic dye substituted with [(L).sub.m-1 -Y] wherein L is a divalent organic linking group containing at least one carbon atom, m is a positive integer 1 or 2, and Y is a cyclic moiety selected from ##STR2## WHEREIN R.sup.1 is hydrogen or a monovalent organic radical; R.sup.

Abstract: A direct positive silver halide light-sensitive material capable of forming direct positive images comprising a support having coated thereon at least one internal image type silver halide emulsion layer, wherein at least one hydrophilic colloid layer contains a heterocyclic quaternary salt compound represented by formula (I) in an amount necessary to provide the silver halide photographic emulsion with a fogging function. ##STR1## wherein Z is an atomic group necessary for completing a 5- or 6-membered heterocyclic nucleus, R.sub.1 is an aliphatic group, R.sub.2 is a hydrazonoalkyl group, X.crclbar. is an anion, and n is 1 or 2.

Abstract: A method of producing direct-positive images is provided which comprises developing an exposed direct-positive silver halide emulsion comprising electron-traps and fogged silver halide grains in the absence of halide ions so as to obtain higher maximum density. It is possible to decrease the degree of fogging so as to obtain direct-positive emulsions of high-sensitivity which, when developed in the absence of halide ions, still provide favorable maximum density values.

Abstract: Heterocyclic N-(acylhydrazinophenyl)thioamide nucleating agents are disclosed as well as radiation-sensitive compositions and elements containing such nucleating agents in combination with silver halide grains capable of forming an internal latent image. The elements can be used to form direct-positive photographic images. Dye image transfer photographic elements are specifically contemplated.

Abstract: Direct positive silver halide emulsions are provided which contain fogged homodisperse silver halide grains having a silver iodide content of more than 10 mole % and at most 20 mole % relative to the total amount of silver halide. These emulsions have higher sensitivity than corresponding fogged emulsions with less silver iodide content.

Abstract: A silver halide photographic emulsion containing at least one sensitizing dye of the following general formula (I) and at least one sensitizing dye of general formulae (II) and/or (III), in an amount effective to achieve supersensitization: ##STR1## wherein V.sup.1 and V.sup.2, which may be the same or different, each represents a hydrogen atom, halogen atom, trifluoromethyl, cyano, carboxy, alkoxycarbonyl, aminosulfonyl or alkylsulfonyl; W.sup.1 and W.sup.2, which may be the same or different, each represents a hydrogen atom, halogen atom, alkyl, alkoxy, hydroxy, acyloxy or phenyl; R.sup.1 represents alkyl or substituted alkyl; R.sup.2 and R.sup.3, which may be the same or different, each represents alkyl or substituted alkyl, and at least one of R.sup.2 and R.sup.3 represents 1 or 0; substituted alkyl containing a carboxy or sulfo radical; R.sup.4 and R.sup.5, which may be the same or different, each has the same meanings as R.sup.1 ; X.sup.- represents an acid anion; and m represents ##STR2## wherein V.

Abstract: A photographic silver halide emulsion capable of forming on exposure an internal latent image can be formed having a desired characteristic curve by providing a first photographic silver halide emulsion comprised of silver halide grains internally sensitized with a combination of middle chalcogen and noble metal sensitizers capable of forming on exposure an internal latent image and blending therewith a second, higher contrast photographic silver halide emulsion comprised of silver halide grains internally sensitized with a relatively lower proportion of middle chalcogen to noble metal sensitization. Both the first and second photographic silver halide emulsions are sensitized with the same middle chalcogen and noble metal sensitizers.

Abstract: A radiation-sensitive composition is disclosed including silver halide grains capable of forming an internal latent image and an acylhydrazinophenylthiourea nucleating agent. This composition can be used as a coating on a support to form a photographic element.

Abstract: Improved dye densities are obtained in color image transfer assemblages employing internal image emulsions, ballasted redox dye releasers and an alkaline processing composition containing a saturated, aliphatic or alicyclic glycol having from 3 to 10 carbon atoms or a saturated, aliphatic or alicyclic amino alcohol having from 2 to 10 carbon atoms.

Abstract: Photographic nucleating agents are disclosed of the formula ##STR1## wherein R is a hydrogen, phenyl, alkylphenyl, cyanophenyl, halophenyl, alkoxyphenyl, alkyl, cycloalkyl, haloalkyl, alkoxyalkyl or phenylalkyl substituent;R.sup.1 is a phenylene or alkyl, halo- or alkoxy substituted phenylene group;R.sup.2 is an alkyl, haloalkyl, alkoxyalkyl or phenylalkyl substituent having up to 18 carbon atoms; a cycloalkyl substituent; phenyl or naphthyl; an alkylphenyl, cyanophenyl, halophenyl or alkoxyphenyl substituent or ##STR2## R.sup.3 is hydrogen, benzyl, alkoxybenzyl, halobenzyl or alkylbenzyl; THE ALKYL MOIETIES, EXCEPT AS OTHERWISE NOTED, IN EACH INSTANCE INCLUDE FROM 1 TO 6 CARBON ATOMS; ANDThe cycloalkyl moieties have from 3 to 10 carbon atoms.

Abstract: A process for obtaining camera speed direct positive images which employs a photographic element comprising a film support, a layer of photosensitive silver halide, and a layer containing a colorant (e.g. colloidal silver). The silver halide layer is first imagewise exposed, and the latent image developed in the presence of a compound capable of producing sulfide ions e.g. thiourea, and then the photographic element is immersed in a chemical bleach which removes the silver image generated in the silver halide layer and removes the colorant in the areas corresponding to the exposed areas of the silver halide layer, leaving a direct positive image in those areas of the colorant-containing layer which are directly under the unexposed nonimage areas of the silver halide layer.

Abstract: Direct-positive emulsions are described comprising incorporated developing agents wherein the developing agents are 1,4-dihydroxybenzene compounds of which at least one of the hydroxyl groups has been esterified to form a hydrolyzable aliphatic acyloxy group comprising a quaternary ammonium group.

Abstract: A process for forming color photographic images which comprises color-developing at temperatures higher than about 30.degree. C a multilayer color photographic material comprising a support having thereon at least two photosensitive emulsion layers each containing a coupler which can form a non-diffusible colored dye on coupling with the oxidation product of an aromatic primary amino color developing agent and at least one fogged emulsion layer containing a coupler which can form a non-diffusible colored dye on coupling with the oxidation product of an aromatic primary amino color developing agent.

Abstract: Processes are disclosed for obtaining positive images in an unfogged, primitive, silver halide emulsion wherein a photographic element comprising a support and said emulsion are imagewise-exposed with a low-intensity light, given an over-all flash exposure with a high-intensity light and developed in a silver halide developer. In one aspect, the silver halide emulsions of this invention are primitive, unfogged, silver halide emulsions which comprise an electron acceptor.

Abstract: Direct positive film with incorporated developer having improved sensitometric properties and storage stability is obtained with a developer combination of hydroquinone monosulfonate and a superadditive developer of the 3-pyrazolidone or the N-methyl-p-aminophenol sulfate types.

Abstract: A process for developing a light-sensitive material which comprises processing a direct reversal silver halide photographic light-sensitive material comprising a support having thereon a silver halide photographic emulsion comprising1. cubic silver halide grains having fogging nuclei therein provided by adding a strong reducing agent to the emulsion and ripening the emulsion, and2.A. a compound acting as an electron acceptor being capable of receiving photoelectrons and also acting as a development accelerator bearing atoms capable of being positively charged in a developer orB. a compound as an electron acceptor capable of receiving photoelectrons and a compound as a development accelerator bearing atoms capable of being positively charged in a developer in an aqueous solution of a hydrophilic colloid with a developer containing a developing agent bearing atoms capable of being negatively charged in the developer is disclosed.

Abstract: Direct-positive silver halide emulsions are described which have been fogged so that a test portion thereof when coated at a coverage of 0.50 to 5.50 g of silver per sq.m. gives a density below 0.50 upon processing without exposure for 6 min. at 20.degree.C in a developer I and an identical coated test portion gives a density that is at least twice that of the first test portion with a minimum of 0.50 upon processing without exposure for 3 min. at 20.degree.C in a developer II.The emulsions have high photographic speed and though fogged to a very low degree can yield direct-positive images of satisfactory density.

Abstract: A photographic multilayer direct-positive silver halide element is provided comprising at least two direct-positive fogged silver halide emulsion layers the undermost emulsion layer comprising one or more non-spectrally sensitizing electron acceptors and the uppermost emulsion layer comprising one or more electron-acceptors at least one of which is a spectrally sensitizing electron acceptor. The direct-positive element has reduced gradation and extended exposure latitude.

Abstract: Direct-positive silver halide emulsions comprising fogged silver halide grains and having adsorbed to the surface of said grains an electron-acceptor have improved stability and speed when subsequent to fogging of said grains and addition of the said electron-acceptor the pH of the emulsion is lowered, preferably below pH 6.

Abstract: A photographic material for producing direct-positive photographic images with at least one silver halide emulsion layer containing unfogged heterodisperse silver halide grains with a core which consists predominantly of silver bromide and a localised phase with a high silver chloride content of at least 20 mols-%, the total concentration of silver chloride, based on the total silver halide content of the grain, is less than 30 mols-%, and at least 10% by weight of the silver halide grains have a diameter which deviates by at least 40% from the average grain diameter in which the silver halide grains are not or only slightly chemically sensitised on the surface.

Abstract: Equidensity images can be produced by imagewise exposure and photographic processing of a photographic material containing at least two silver salt emulsions which may be arranged in one layer as a mixture or in two layers, wherein one silver salt emulsion is a fogged direct positive emulsion and the other is a negative emulsion.

Abstract: My invention is directed to a photographic element capable of forming either a positive or a negative image, depending upon the choice of electromagnetic wavelengths to which it is exposed. The element inludes internally fogged photographic silver halide grains which are substantially free of surface fog. Associated with the grains is a desensitizer containing an imidazoquinoxaline nucleus having a reduction potential more positive than -0.90 volts and an oxidation potential more positive than +0.80 volt. The desensitizer is present in an amount of no more than that required to cover 25 percent of the silver halide grain surfaces. Also associated with the grains is a spectral sensitizing dye having an absorption peak at least 20 nm removed from any absorption peak exhibited by the desensitizer.

Abstract: A direct-positive photographic material for producing images by fogging development wherein the photographic material contains an unfogged silver halide emulsion layer. The silver halide grains in the unfogged emulsion have a layered grain structure wherein there is a first phase in which is localized a relatively high silver chloride content of at least 20 mol percent based on the total silver halide content of the grain. A second phase contains from less silver chloride than the first phase down to no silver chloride and the total silver chloride in the grain does not exceed 30 mol percent.The physical position of the first phase in the grain is not critical.The emulsion is either not chemically sensitized or only slightly sensitized.The photographic material and its use includes both producing black and white and colored photographic images and has high sensitivity to light and by fogging development yields pure image whites.

Abstract: Direct positive silver halide materials based on the Herschel effect having substantially reduced sensitivity to room light exposure contain a heterocyclic compound to prevent white light bleaching along with a second heterocyclic compound to prevent latent image formation due to white light exposure.

Abstract: .Iadd.Light-sensitive photographic direct positive silver salt emulsions for use in photographic elements are disclosed. The emulsions contain silver salt grains, typically silver halide grains. The silver salt grains are comprised of a core containing centers which promote the deposition of photolytic silver and a shell covering the core. The shell is fogged and develops to silver without exposure. .Iaddend.