Abstract: Acoustic transducers generate and receive acoustic signals at multiple locations along a surface of rigid structure, wherein longitudinal spacing between transducer locations define measurement zones. Acoustic signals with chosen amplitude-time-frequency characteristics excite multiple vibration modes in the structure within each zone. Small mechanical changes in inspection zones lead to scattering and attenuation of broadband acoustic signals, which are detectable as changes in received signal characteristics as part of a through-transmission technique. Additional use of short, narrowband pulse acoustic signals as part of a pulse-echo technique allows determination of the relative location of the mechanical change within each zone based on the differential delay profiles. For accurate acoustic modeling and simulation, the mesh size, time step, time delay, and time-window size are optimized.

Abstract: Methods for detection, monitoring, and determination of location of changes in rigid structures with arbitrarily complex geometries are described. Implementations include locating acoustic transducers that generate and receive acoustic signals at multiple locations along a surface of the rigid structure, wherein longitudinal spacing between the transducer locations define measurement zones. Acoustic signals with chosen amplitude-time-frequency characteristics excite multiple vibration modes in the structure within each zone. Small mechanical changes in the inspection zones lead to scattering and attenuation of broadband acoustic signals, which are detectable as changes in received signal characteristics as part of a through-transmission technique. Additional use of short, narrowband pulse acoustic signals as part of a pulse-echo technique allows determination of the relative location of the mechanical change within each zone based on the differential delay profiles.

Abstract: Methods for detecting and monitoring changes in mechanical structures and in walls of pipes, vessels and storage tanks, using muitimode acoustic signal propagation and detection, are described. Acoustic signals having chosen amplitude-time-frequency characteristics excite multiple modes in the structure under investigation, are generated and received at a small number of accessible locations, such as the ends of pipes and the tops and bottoms of vessels and storage tanks, with the inspection region between transmit and receive transducers. Small mechanical changes lead to acoustic scattering and attenuation among the various modes, which are detectable as changes in received signal intensity. Such changes may include material loss, material conversion and material addition. Once the structure is characterized in a known condition, the present method may be used to monitor the structure at a later time to determine whether changes have taken place.

Abstract: Methods for detection, monitoring, and determination of location of changes in rigid structures with arbitrarily complex geometries are described. Implementations include locating acoustic transducers that generate and receive acoustic signals at multiple locations along a surface of the rigid structure, wherein longitudinal spacing between the transducer locations define measurement zones. Acoustic signals with chosen amplitude-time-frequency characteristics excite multiple vibration modes in the structure within each zone. Small mechanical changes in the inspection zones lead to scattering and attenuation of broadband acoustic signals, which are detectable as changes in received signal characteristics as part of a through-transmission technique. Additional use of short, narrowband pulse acoustic signals as part of a pulse-echo technique allows determination of the relative location of the mechanical change within each zone based on the differential delay profiles.

Abstract: Methods for detecting and monitoring changes in mechanical structures and in walls of pipes, vessels and storage tanks, using muitimode acoustic signal propagation and detection, are described. Acoustic signals having chosen amplitude-time-frequency characteristics excite multiple modes in the structure under investigation, are generated and received at a small number of accessible locations, such as the ends of pipes and the tops and bottoms of vessels and storage tanks, with the inspection region between transmit and receive transducers. Small mechanical changes lead to acoustic scattering and attenuation among the various modes, which are detectable as changes in received signal intensity. Such changes may include material loss, material conversion and material addition. Once the structure is characterized in a known condition, the present method may be used to monitor the structure at a later time to determine whether changes have taken place.

Abstract: A method for evaluating a vessel for suitability to contain a fluid includes providing a vessel and forming a polished surface portion of the vessel by removing oxidation and/or contaminants from a portion of the vessel. The method further includes applying a focused laser to the polished surface portion to form plasma on the polished surface portion, and determining whether the vessel is suitable for containing a fluid based on silicon content of the polished surface portion. The silicon content is estimated based on light emitted from the plasma.

Abstract: A method for evaluating a vessel for suitability to contain a fluid includes providing a vessel and forming a polished surface portion of the vessel by removing oxidation and/or contaminants from a portion of the vessel. The method further includes applying a focused laser to the polished surface portion to form plasma on the polished surface portion, and determining whether the vessel is suitable for containing a fluid based on silicon content of the polished surface portion. The silicon content is estimated based on light emitted from the plasma.

Abstract: In the present method of drying iron ore pellets, e.g., magnetite pellets, moisture-containing iron ore pellets are formed into a bed comprising a multiplicity of the pellets. A current of drying gas is forced through the bed of pellets to at least partially dry some of the pellets. At least one jet of a drying gas that contains added oxygen is directed onto the bed of pellets so to impinge upon a surface of the pellet bed thereby providing kinetic energy for directing oxygen including the added oxygen into the pellets so as to enhance the conversion of magnetite to hematite. Moisture can be added to heated air that is then blown through jet nozzles onto the pellet bed or circulated back to an earlier drying stage and passed through the bed.

Abstract: In the present method of drying iron ore pellets, e.g., magnetite pellets, moisture-containing iron ore pellets are formed into a bed comprising a multiplicity of the pellets. A current of drying gas is forced upwardly through the bed of pellets to at least partially dry some of the pellets. Radiant heat reflectors above the bed reflect heat back onto the pellets with air jets simultaneously directing air downwardly onto the top surface of the bed. Air is forced between the reflectors are placed and onto the bed to, especially below the firebrick wall between the end of the updraft drying zone and the downdraft drying zone. Water is applied to the hot pellets to produce steam as well as water vapor which is added to a current of air to produce a stream of hot, humid air that is passed through the bed to improve pellet characteristics and recover waste heat.

Abstract: In the present method of drying iron ore pellets, e.g., magnetite pellets, moisture-containing iron ore pellets are formed into a bed comprising a multiplicity of the pellets. A current of drying gas is forced upwardly through the bed of pellets to at least partially dry some of the pellets. A plurality of pipes, each having an opening such as an elongated slot provides counter-current jets of a drying gas above the bed. The drying gas jets are directed downwardly so as to impinge on the upper surface of the bed through which the current of drying gas rises. The bed of pellets is thus dried with the current of drying gas flowing through the bed from below as well as the jets of drying gas impinging onto the upper surface of the bed. In a preferred form of the invention, in a second stage downwardly directed jets of drying gas are used together with a downward current of drying gas to further dry the pellets before they are fired.