Abstract: A centrifuge for a semiconductor wafer has a centrifuge plate for holding a semiconductor wafer, has a drive for setting the centrifuge plate in rotation, and has a device for supplying a medium to a front side and a rear side of the semiconductor wafer. The centrifuge has a housing which separates a centrifuging area and the semiconductor wafer from the environment, and a device for generating a laminar gas flow in the housing. A method for centrifuging a semiconductor wafer has the semiconductor wafer being centrifuged in a laminar gas flow.

Abstract: Wafer cleaning systems (10, 25) utilizing both chemical and physical action to clean integrated circuit wafers (14, 24) is disclosed. Chemical cleaning action is provided by liquid retained within a tank (2, 22), sized either to hold a single wafer (24) or a batch of wafers (14) held within a carrier (12). Physical action is provided in the wafer cleaning system either by way of inert gas bubbling through a baffle (5) or by way of ultrasonic energy applied by transducers (28) located in the tank (2, 22). The systems (10, 25) have a programmable controller (20, 30) for initiating the physical cleaning action after insertion of the wafers (14, 24) into the chemical bath, and for ceasing the physical action prior to removal of the wafers (14, 24). After a waiting time after the ceasing of the physical action, to calm the chemical bath and to permit any retained bubbles to escape to the atmosphere, the wafers (14, 24) may then be removed from the chemical bath, with reduced risk of staining and particle release.

Abstract: A method and an apparatus that uses a surfactant to clean a hydrophobic wafer is provided. In a first aspect, the method may clean and dry a wafer without applying pure DI water to the wafer. In a second aspect, the method may clean a wafer by applying pure DI water to the wafer only for a short duration of time such that the DI water application ceases prior to or as soon as a surfactant solution is rinsed from the wafer thereafter the wafer is dried. In a further aspect a hydrophobic wafer is maintained wetted with surfactant as it is transferred between cleaning apparatuses and is rinsed via diluted surfactant or via a brief DI water spray and is thereafter dried.

Abstract: A method for cleaning phosphorus from a MBE vacuum chamber by freezing the panel (22) placed within the vacuum chamber (10) onto which excess phosphorus is deposited. The panel is connected to a source of cold nitrogen (24) which cools the panel. Water is introduced after the panels are cooled so as to form a layer of ice on top of the phosphorus. The panel may then be removed for cleaning with ice covering the phosphorus without danger of ignition of the phosphorus.

Abstract: Oxides on the surfaces of metal are reduced by directing reducing gases at them in a forceful and turbulent manner. In a preferred version, the gas is passed through at least two reducing zones designed to maintain a higher concentration of reducing gas in at least one of them than would be the case in a single reducing zone. The oxide-bearing surface is heated at the beginning of the process.

Abstract: Equipment used in the processing of plastic, such as molds and extrusion screws, is cleaned of plastic residue by a combination of thermal cycling and agitation without impact cleaning. A chamber can be heated by an electric radiant heater and cooled by the introduction of liquid nitrogen. A fixture in the chamber receives the equipment to be cleaned and is agitated by a drive motor. The chamber is heated and cooled in the following cycle in which the drive motor agitates the fixture: first to 250-300° F., then to −315° F., then cycled between −50° F. and −10° F., then to 150° F., then to −200° F., to 100° F., then to ambient temperature. The chamber is controlled by a computer that prompts the operator for the kind of plastic to be cleaned off of the equipment and then controls the heating and cooling automatically.

Abstract: Oxides on the surfaces of metal are reduced by directing reducing gases at them in a forceful and turbulent manner in an enclosure. The oxide-bearing surface is heated to at least 900 degrees F.

Abstract: A method is for processing semiconductor material, in which one or more shock waves generated using a transducer are transmitted through a liquid medium to semiconductor material in rod form. The transducer is at a distance of from 1 cm to 100 cm from the semiconductor material, and the shock waves have a pulse energy of from 1 to 20 kJ and a pulse rise time to the energy maximum of from 1 to 5 &mgr;s.

Abstract: The invention includes compositions and methods for sanitizing ware without staining, spotting or corroding. In its most preferred mode, the method comprises the steps of washing the ware in an automated ware washing machine and rinsing the ware at either high or low temperatures with a sanitizing rinse composition. The destaining, sanitizing concentrate composition preferably comprises peroxyacetic acid, acetic acid, and hydrogen peroxide using higher levels of acetic and peroxyacetic acid and a lower level of hydrogen peroxide. The sanitizing rinse composition may preferably be used at a concentration of peroxyacetic acid of at least 30 ppm.

Abstract: According to a first aspect of this invention, it is assumed that the recording is carried out on the recording medium by a non-catalyst-containing recording agent and a liquid-state catalyst is coated on the recording medium at the time of erasing processing and subsequently the heating and irradiation of near infrared rays are carried out as the erasing processing. Also, according to a second aspect of this invention, it is assumed that the recording is carried out on the recording medium by a catalyst-containing recording agent and, at the erasing processing time, the heating and irradiation of the recording agent are simultaneously carried out using a thermal emission and near IR irradiation source such as a halogen lamp.

Abstract: A method of removing graphite from metal molds used in the glass fabrication industry, the method including placing a metal glass-fabricating mold with graphite bonded thereto in a chamber, providing an oxygen rich mixture of combustible gases in the chamber, said oxygen rich mixture containing from about 10 to about 25% stoichiometric excess of oxygen, and igniting the oxygen rich mixture of combustible gases in the chamber to produce a temperature of at least about 6,000° F. and a pressure wave. A high temperature wave front and the pressure wave thereby produced remove graphite from the metal mold by ablation of the graphite.

Abstract: Oxides on the surfaces of metal are reduced by directing reducing gases at them in a forceful and turbulent manner in an enclosure. The oxide-bearing surface is heated to at least 900 degrees F.

Abstract: A cleaning method to inhibit the adhesion of micro particles to a member to be cleaned by decreasing an amount of generation of bubbles. In a method for cleaning a member to be cleaned by dipping the member into a cleaning bath to which a hydrochloric acid-hydrogen peroxide mixture comprising hydrochloric acid, hydrogen peroxide and water is supplied through a filter and a supplying port; the improvement is that a temperature of the hydrochloric acid, hydrogen peroxide mixture is controlled within the range of 20°to 45° C.

Abstract: The invention discloses a starch graft poly(meth)acrylate blast media which is effective in paint removal. The media is superior to a physical blend of the components (i.e., starch and acrylic polymers) and to either a starch polymer or an acrylic polymer used singly. The hardness of the media is between 65-90 Shore D.

Abstract: Compounds containing two cyclic hydrocarbon moieties which are substituted to provide crosslinking functionality and which are linked to each other by secondary or tertiary oxycarbonyl containing moiety are basis for compositions which are cured to provide cured thermosets for encapsulation and underfill for electronic components that are thermally decomposable to allow repair, replacement, recovery or recycling of operative electronic components from assemblies that are inoperative.

Abstract: Equipment used in the processing of plastic, such as molds and extrusion screws, is cleaned of plastic residue by a combination of thermal cycling and agitation without impact cleaning. A chamber can be heated by an electric radiant heater and cooled by the introduction of liquid nitrogen. A fixture in the chamber receives the equipment to be cleaned and is agitated by a drive motor. The chamber is heated and cooled in the following cycle in which the drive motor agitates the fixture: first to 250-300.degree. F., then to -315.degree. F., then cycled between -50.degree. F. and -10.degree. F., then to 150.degree. F., then to -200.degree. F., then to 100.degree. F., then to ambient temperature. The chamber is controlled by a computer that prompts the operator for the kind of plastic to be cleaned off of the equipment and then controls the heating and cooling automatically.

Abstract: A method and apparatus for the cleaning of residue from the surface of a container where the method comprises cooling the container and residue adhered to the container surface to a low temperature, substantially embrittling the residue, fragmenting the residue, separating the residue from the surface of the container and removing the residue from the container. The container is placed in an enclosure with an opening in the top of the enclosure to permit access to the interior of the container when a container lid is removed. The system includes a rotating base to turn the container to facilitate freezing and removal of the residue.

Abstract: A process for continuously discriminating between a contaminated plastic material containing trapped volatile contaminants and plastic material which contains an acceptable threshold of contaminants comprising first supplying a continuous source of plastic material wherein the plastic material contains trapped volatile contaminants and feeding a sample of the plastic material preferably to the input section of an auger conveyor. The auger conveyor contains a barrel and a transfer screw positioned within the barrel with flights thereon for conveying the plastic material, the auger also connected to an output section which itself is connected to a detector for detecting trapped volatile contaminants.

Abstract: Surface cleaning, chemical treatment and drying of semiconductor substrates is carried out using foam as a medium instead of a condensed phase liquid medium. In cleaning and chemical treatment, by introducing a foam into an overflow vessel the foam is caused to pass over the substrate in moving contact therewith. Drying of the substrate is carried out, using a water solution of carbon dioxide in a pressurizable vessel. By releasing the pressure in the vessel, a layer of foam is established on the surface of the solution. The solution is discharged from the vessel, causing the foam layer to pass over the substrate in moving contact therewith. The carbon dioxide reduces the surface tension of the water, thereby enabling the foam layer to be produced and also assisting in the elimination of water from the surface of the substrate. In both cases, the use of foam reduces materials requirements and also reduces the quantity of particles deposited onto the substrate in the treatment process.

Abstract: A method of removing layers of heat cured paint buildup on supporting hangers is disclosed. The method includes coating support hangers with a layer of a thermally expandable material in a water soluble carrier and thereafter applying a water insoluble coating layer. The thermally expandable material, the carrier and the water insoluble coating are all selected so as to be relatively unaffected by the curing temperatures of the paint line where the hangers are to be used. When an undesirably thick coating of cured paint has built-up on the hangers, it is removed by heating to a temperature sufficient to expand the thermally expandable material thereby cracking the paint layers. Thereafter, the hangers are soaked in a hot aqueous solution to dissolve the carrier layer and remove the cracked, cured paint layers.

Abstract: The invention discloses a starch graft poly(meth)acrylate blast media which is effective in paint removal. The media is superior to a physical blend of the components (i.e., starch and acrylic polymers) and to either a starch polymer or an acrylic polymer used singly. The hardness of the media is between 65-90 Shore D.

Abstract: A method for removal of asbestos floor tile comprising the following steps: lowering the temperature of a selected tile section and the adhesive material between said tile(s) and the juxtaposed subflooring; maintaining the temperature reducing agent for a period of time sufficient to cause said adhesive material/layer to substantially lose its bonding properties; removing the de-bonded asbestos tile from the subflooring and disposing according to Governmental regulations. A manually transportable housing dimensioned for receiving therewithin a quantity or block of dry ice. The housing having a bottom section defining an opening for being aligned with a selected asbestos floor tile(s). A blower means mounted to said housing for directing an air stream over said dry ice and downwardly through said opening unto said tile(s).

Abstract: A method and a device for cleaning and exposing portions of limited length of strands of steel wire which are surrounded by a corrosion protection substance, particularly grease, wherein the strands of steel wire and the corrosion protection substance are enclosed by a sheathing of synthetic material. Initially, the sheathing is severed at a distance from the end of the strand corresponding to the length of the portion to be cleaned and an opening is produced. Subsequently, a flushing pipe is connected to the sheathing at the end of the strand and the strand is cleaned by admitting a flushing liquid under high pressure into the space surrounded by the sheathing, so that the corrosion protection substance and the flushing liquid emerge at the opening. Finally, the sheathing is removed entirely from the strand by pulling off the sheathing.

Abstract: An apparatus for heating a metal surface to remove a nonferrous thermosetting resin coating bonded to the metal surface. The apparatus uses a power supply device for providing an approximately 75-100 kW signal at approximately 10-40 kHz to the apparatus. A coil assembly device is coupled to the power supply device for producing a high frequency inductive field which will penetrate through the nonferrous thermosetting resin coating with virtually no attenuation and will induce an eddy current of sufficient power in the underlying metal substrate to rapidly heat the interface to a sufficient temperature to immediately destroy the interface bond between the nonferrous thermosetting coating and the metal substrate.

Abstract: High volume manufacturing process for flexographic printing plates comprises wash out, drying and post-exposure. During drying the printing plates are transported with a plurality of endless conveyors. The transport speed during drying/post-exposure is lower than the transport speed during wash out such that a storage of flexographic plates can be achieved in the drying and post exposure portion of the process.

Abstract: An apparatus having a self contained heat source and water supply enables the wet removal of adhesively secured floor tile upon application of heat. The apparatus includes an infrared heater fed by a propane fuel tank and a water supply fed by a pressurizing water system. The method of removing floor tiles upon application of heat in a wet environment minimizes airborne asbestos dust or other contaminants. The self contained infrared heater eliminates any potential of electrical shock hazard.

Abstract: In order to utilize separately steel pipe and coating resin as recycling resources, resin-coated steel pipe, which is produced by adhering a thermo-plastic coating resin on the surface of steel pipe with an adhesive, is heated by high-frequency induction heating to at least the melting temperature of the coating resin, and the coating resin is scraped off while the inner layer thereof is in a melted condition and the outer layer is in a softened condition. Coating resin and steel pipe can be recovered without the composition thereof being damaged. The scraping of coating resin is complete and efficient and requires only minimal energy since it occurs when the inner layer of the coating resin is in a melted condition and the outer layer is in a softened condition.

Abstract: A method and apparatus for the cleaning of residue from the surface of a container where the method comprises cooling a container and residue adhered to the container surface to a low temperature, substantially embrittling the residue and then impacting the container to fragment and separate the residue from the surface of the container. The cooling may be effected by contacting cold vaporized cryogen to the residue and container in an insulated box having a cryogen sprayer, an opening, and a door. A method for reducing the bulk volumes of containers comprising cooling the container to a low temperature to substantially embrittle the container and then stressing the container to fracture and break apart the embrittled portions and thereby reduce the bulk volume of the container.

Abstract: An apparatus and method by which deposits are removed from the heat exchange surfaces of heat exchange element in a boiler. According to the present invention, a heat exchange medium flowing through the element at a first temperature has injected into it a fluid at a second temperature. The injection of the fluid and the temperature difference between the fluid and the medium causes a pressure wave to be produced in the heat exchange element at a specific location whereby the pressure wave in the medium causes mechanical vibration of the element. The result is that ash, scale, soot and other deposits are fractured, loosened and removed from the surfaces of the element.

Abstract: A method for removal of asbestos floor tile comprising the following steps: lowering the temperature of a selected tile section and the adhesive material between said tile(s) and the juxtaposed subflooring; maintaining the temperature reducing agent for a period of time sufficient to cause said adhesive material/layer to substantially lose its bonding properties; removing the de-bonded asbestos tile from the subflooring and disposing according to Governmental regulations.A manually transportable housing dimensioned for receiving therewithin a quantity or block of dry ice. Said housing having a bottom section defining an opening for being aligned with a selected asbestos floor tile(s). Blower means mounted to said housing for directing an air stream over said dry ice and downwardly through said opening unto said tile(s).

Abstract: A method for removing radioactive barium sulphate from fluid carrying equipment includes immersing the equipment and scale in liquid nitrogen or other cyrogenic liquid, followed by immersing the equipment and scale in water or other aqueous solution, and subsequent impacting of the equipment and scale to remove the scale.

Abstract: A method for removal of asbestos floor tile comprising the following steps: lowering the temperature of a selected tile section and the adhesive material between said tile(s) and the juxtaposed subflooring; maintaining the temperature reducing agent for a period of time sufficient to cause said adhesive material/layer to substantially lose its bonding properties; removing the de-bonded asbestos tile from the subflooring and disposing according to Governmental regulations.A manually transportable housing dimensioned for receiving therewithin a quantity or block of dry ice. Said housing having a bottom section defining an opening for being aligned with a selected asbestos floor tile(s). Blower means mounted to said housing for directing an air stream over said dry ice and downwardly through said opening unto said tile(s).

Abstract: A method for removing tile adhered by a substance to a floor includes the step of enclosing a volume generally above an area of the floor and tile, with the tile and floor defining the bottom of the volume enclosed. The temperature in the volume enclosed is reduced so that the substance adhering the tile to the floor becomes embrittled. The apparatus is maintained in position over the area of the floor for a predetermined time to produce the required embrittlement of the adhering substance, and then moved to expose the area of the floor previously below the volume enclosed. The tile is then removed from the floor. An apparatus for use in the method is also disclosed.

Abstract: A machine for refinishing a rim/wheel by first elevating the rim/wheel from ground level into a washing and degreasing chamber, washing and degreasing the rim/wheel in the chamber, transferring the rim/wheel into a shot blast chamber, shot-blasting the rim/wheel, transferring the rim/wheel to a spray coating area, spray-coating the rim/wheel with a protective material, and thereafter returning the rim/wheel to its initial elevation for subsequent tire/retread application thereto. The rim/wheel is transferred through the machine with its axis in a generally horizontal plane and is also rotated about its axis during washing/degreasing and shot-blasting. During the spray coating, the rim/wheel is coated with its axis disposed both vertically and horizontally.

Abstract: The present invention is a method for using a horizontal, continuous process auger centrifuge to separate the granulated material of a container from whatever liquid residue remains within the container. Though this technology is suitable for many diverse applications, a primary objective is the continuous separation of the recyclable plastic of a motor oil container from the remaining reusable motor oil within the container after the container has ostensibly been emptied. It is an objective of the method to accomplish this separation in an economically advantageous manner which uses neither a solvent nor a wash process, and which reclaims the oil in a suitable state for reprocessing. In a second method, a rinsing mechanism is employed by which a residual liquid waste, such as soap, may be concentrated and separated in a first rinse stage without introducing the residual liquid waste in dilute form into the waste water treatment process.

Abstract: An improved method for removing sludge and corrosion products from the interior of a heat exchanger vessel, such as a nuclear steam generator, which comprises the steps of generating a series of pressure pulses within a liquid chelate-containing chemical cleaning agent after the agent has been introduced into the interior of the vessel to create shock waves in the liquid for dislodging, dissolving and fluidizing sludge and corrosion products. The liquid chemical cleaning agent is removed from the vessel after only about 10 to 70 percent of what would have been its normal residence time without the pressure pulses.

Abstract: The invention is a cleaning method and associated apparatus that are particularly useful for cleaning surfaces formed of relatively hard materials such as grout or industrial rolls which are contaminated with relatively hard embedded deposits of undesirable materials that are difficult to remove by conventional washing or abrading cleaning methods, and while substantially reducing the effluent resulting from the cleaning step so that the cleaning method may be conveniently used in areas where effluent disposal may be a problem such as smaller indoor rooms, areas, or equipment. The invention comprises pressurizing a cleaning liquid with a gas driven hydraulic pump and directing a flow of the cleaning liquid from a nozzle at surfaces to be cleaned at a pressure of at least about 5,000 pounds per square inch (psi) and at a volumetric flow rate of no more than about 1.

Abstract: In homogeneous substitution washing method and apparatus for a cake using a filter press which comprises pairs of opposed squeezed and squeezing filtering plate units, pairs of opposed squeezed and squeezing filtering cloths, each pair of filtering cloths being arranged between the pair of filtering plate units, and diaphragms. Each diaphragm is arranged on one side of one of the pair of filtering plate units. Stock solution is supplied into a space between the pair of filtering cloths, and is pressurized and dehydrated by the diaphragm to form the cake. The cake is processed in washing to obtain a clean raw material. In parallel with the pressurizing and dehydrating step of the stock solution, a washing liquid is poured into a space between the diaphragm and the squeezing filtering cloth abutted against the diaphragm, at a pressure at least a pressurizing and dehydrating pressure applied to the stock solution through the diaphragm, to wash the cake between the pair of filtering cloths.

Abstract: To remove a thick insulating coating from a steel pipeline, with high efficiency and speed, multiple cooling and scraping steps are performed sequentially. In a first cooling step, a low temperature coolant is sprayed onto the coating for a time sufficient to cool only a portion of the coating to a temperature below the embrittlement temperature thereof. After scraping away the embrittled outer layers of the coating, subsequent cooling and scraping steps are performed until all of the coating has been embrittled and removed. It has been found that the time required for removing the coating by use of such multiple spraying and scraping steps is substantially less than that where the coating is to be embrittled in a single step.

Abstract: Particles adhering to the internal surfaces of an object are removed by the movement of a shock wave past the surfaces. The shock wave is generated by the explosion of a gas in a chamber located inside the object. The invention has particular application for use in cleaning process equipment.

Abstract: An apparatus to remove rubber from airplane tires from an airport runway surface. There is a manifold arm which rotates at as high as two thousand five hundred rpms over the runway surface, with a plurality of water jets being discharged downwardly at a relatively high pressure (e.g. thirty five thousand P.S.I.) against the runway surface. Even though the water pressure as at a level several times higher than that at which damage to the runway surface can occur, at the relatively high linear speed of the water jets (e.g. ninety to one hundred eighty miles per hour), there is no noticeable damage to the runway surface, but yet there is quite effective removal of the accumulated rubber. Also disclosed is a particular shaft and seal assembly which is capable of operating at relatively high rotational speeds and delivering the high pressure to the manifold arm.

Abstract: In non-aqueous liquid cleaning products compositions comprising dispersed particles of aluminosilicate builder, components sensitive to decomposition catalyzed by aluminosilicate, such as bleach precursors, can be protected if the aluminosilicate particles are deactivated by pre-treatment with an ammonium or substituted ammonium compound, followed by a heating step to reduce the water level of the aluminosilicate.

Abstract: A process for removing contaminants such as phenolic-containing dusts and mists from an inert gaseous process stream by contacting the gaseous stream with an aqueous alkali metal hydroxide solution whereby the contaminants react with the alkali metal hydroxide to produce alkali metal salts of the contaminant compounds and produce water soluble contaminant salts.

Abstract: Paint is removed from surfaces by impacting it with particles of cured unsaturated polyester including about 10-20 weight weight percent methyl methacrylate, the particles having a low ratio of longest to shortest dimension and an average of at least about 40 facets.

Abstract: A method for removing organic and inorganic deposits from hydrophilic (contact) lenses and minimizing shape deformation thereof, comprising immersing the lenses in an aqueous solution of water and a hypertonic, substantially nontoxic cryoscopic modifying agent, reducing the temperature of the solution to between 0.degree. C. and -4.degree. C., thereby causing the solution to freeze and expand and causing the lens structure to contract, and causing the liquid volume to exceed the lens hydrogel volume and expelling deposits in the lens and on the lens surface.

Abstract: A method is described for blast cleaning paint and other adhesive coatings from composite surfaces formed of a reinforced matrix material. A special soft media is used at a relatively low pressure to prevent damage to the soft composite material. The preferred method calls for the use of a media having a Mohs scale hardness number of 3.0 or less. The media is pressurized to approximately 40 p.s.i. and directed at the composite surface to be cleaned. A method of optimizing the cleaning action is also described.

Abstract: A process for removing layers of paint or other non-metallic coatings from a coated metal hanger or the like comprising the steps of freezing the coating to embrittle it and shrink it toward the metal hanger, heating the metal hanger without heating the coating to expand the metal toward the coating, and stressing the coating by said expanding and shrinking to break and fragment the coating and cause it to fall off the metal hanger.

Abstract: The present invention relates to an improved method of cleaning a nuclear steam generator by removing the buildup of deposits which accumulate on the upper tube support plates, on the heat exchanger tubes, on flow holes in the support plates and between the support plates and heat exchanger tubes, and on other secondary side surfaces of a heat exchanger vessel through utilization of a repetitive shock wave induced in the deposits. The shock wave serves to effectively and safely loosen the products of corrosion and other elements which settle on these surfaces of the heat exchanger vessel and thereby facilitiates their easy removal through flushing and vacuuming the vessel. The shock waves are induced by air-gun type pressure pulse shock wave sources or pressurized gas-type pressure pulse shock wave sources.

Abstract: The present invention relates to an improved method of cleaning a tube bundle heat exchanger by removing the buildup of sedimentation or "sludge" which accumulates in the bottom or at other elevations of a heat exchanger vessel through utilization of a repetitive shock wave induced in the liquid layer above the sludge. The shock waves are induced by air-gun type pressure pulse shock wave sources or pressurized gas-type pressure pulse shock wave sources. The shock wave serves to effectively and safely loosen the products of corrosion and other elements which settle at the bottom of the heat exchanger or steam generator and thereby facilitates their easy removal through flushing and vacuuming the vessel.

Abstract: The present invention relates to an improved method of cleaning and removing the products of corrosion, oxidation and sedimentation which occur within and become attached to the walls of the interior of heat exchanger tubes which are located within a pressure vessel such as a tube bundle heat exchanger, boiler, condenser or the like, through utilization of a repetitive shock wave induced into a liquid which is placed within the tubes and then subsequently flushing the tubes. The shock wave serves to effectively and safely loosen the products of corrosion, oxidation and sedimentation which are located within or settle on the walls of the interior of the heat exchanger tubes, and thereby facilitates their easy removal through flushing and vacuuming the vessel. The shock waves are induced by air-gun type pressure pulse shock wave sources or pressurized gas-type pressure pulse shock wave sources.