Abstract: A method of treating an elongated conductive element comprises exposing a conductive element sequentially to at least two dopants being different in composition. The dopants may include an acidic dopant and a halogen-based dopant. The conductive element comprises a plurality of carbon nanotubes and has a linear density in a range from about 0.1 tex to about 2.0 tex. The method further comprises mechanically densifying the conductive element. The elongated conductive element comprises at least one carbon nanotube fiber doped with a plurality of p-type dopants comprising at least one acidic dopant and at least one halogen-based dopant. The at least one carbon nanotube fiber has an electrical resistivity equal to or less than about 55 ??·cm and an ultimate tensile strength equal to or greater than about 1 GPa.

Abstract: A method of making a thin film substrate involves exposing carbon nanostructures to a crosslinker to crosslink the carbon nanostructures. The crosslinked carbon nanostructures are recovered and disposed on a support substrate. A thin film substrate includes crosslinked carbon nanostructures on a support substrate. The crosslinked carbon nanostructures have a crosslinker between the carbon nanostructures. A method of performing surface enhanced Raman spectroscopy (SERS) on a SERS-active analyte involves providing a SERS-active analyte on such a thin film substrate, exposing the thin film substrate to Raman scattering, and detecting the SERS-active analyte.

Abstract: A method of treating an elongated conductive element comprises exposing a conductive element sequentially to at least two dopants being different in composition. The dopants may include an acidic dopant and a halogen-based dopant. The conductive element comprises a plurality of carbon nanotubes and has a linear density in a range from about 0.1 tex to about 2.0 tex. The method further comprises mechanically densifying the conductive element. The elongated conductive element comprises at least one carbon nanotube fiber doped with a plurality of p-type dopants comprising at least one acidic dopant and at least one halogen-based dopant. The at least one carbon nanotube fiber has an electrical resistivity equal to or less than about 55 ??·cm and an ultimate tensile strength equal to or greater than about 1 GPa.

Abstract: A method of treating an elongated conductive element comprises exposing a conductive element sequentially to at least two dopants being different in composition. The dopants may include an acidic dopant and a halogen-based dopant. The conductive element comprises a plurality of carbon nanotubes and has a linear density in a range from about 0.1 tex to about 2.0 tex. The method further comprises mechanically densifying the conductive element. The elongated conductive element comprises at least one carbon nanotube fiber doped with a plurality of p-type dopants comprising at least one acidic dopant and at least one halogen-based dopant. The at least one carbon nanotube fiber has an electrical resistivity equal to or less than about 55 ??·cm and an ultimate tensile strength equal to or greater than about 1 GPa.

Abstract: A filter membrane includes carbon nanotubes and carbon nitride nanoparticles. Inter-particle atomic interactions between the carbon nanotubes and the carbon nitride nanoparticles bind the carbon nanotubes and the carbon nitride nanoparticles together. A filter cartridge includes such a filter membrane disposed within an outer housing between a fluid inlet and a fluid outlet such that fluid passing through the outer housing between the fluid inlet and the fluid outlet passes through the filter membrane. Such filter membranes may be formed by dispersing carbon nanotubes and carbon nitride nanoparticles in a liquid to form a suspension, and passing the suspension through a filter to deposit the nanotubes and nanoparticles on the filter. Liquid may be filtered by causing the liquid to pass through such a filter membrane.

Abstract: A system and method for estimating a concentration of monoethanolamine (MEA) in a fluid. A substrate for supporting a sample of the fluid during testing includes a carbon nanotube mat layer, a silver nanowire layer disposed on the carbon nanotube mat layer, and a chemical enhancer layer disposed on the silver nanowire layer. A sample of the fluid is placed on the substrate, and the fluid sample is radiated with electromagnetic radiation at a selected energy level. A detector measures a Raman spectrum emitted from the sample in response to the electromagnetic radiation. A processor estimates the concentration of MEA in the sample from the Raman spectrum and adds a corrosion inhibitor to the fluid in an amount based on the estimated concentration of MEA to reduce the concentration of MEA in the fluid.

Abstract: A method and apparatus for estimating a concentration of chemicals in a fluid flowing in a fluid passage is disclosed. A sample of the fluid is placed on a substrate comprising a first layer of carbon nanotubes and a second layer of metal nanowires. An energy source radiates the fluid sample with electromagnetic radiation at a selected energy level, and a detector measures an energy level of radiation emitted from the fluid sample in response to the electromagnetic radiation. A processor determines a Raman spectrum of the fluid sample from the energy level of the emitted radiation and estimates the concentration of a selected chemical in the fluid sample based on the Raman spectrum.

Abstract: A system and method for estimating a concentration of monoethanolamine (MEA) in a fluid. A substrate for supporting a sample of the fluid during testing includes a carbon nanotube mat layer, a silver nanowire layer disposed on the carbon nanotube mat layer, and a chemical enhancer layer disposed on the silver nanowire layer. A sample of the fluid is placed on the substrate, and the fluid sample is radiated with electromagnetic radiation at a selected energy level. A detector measures a Raman spectrum emitted from the sample in response to the electromagnetic radiation. A processor estimates the concentration of MEA in the sample from the Raman spectrum and adds a corrosion inhibitor to the fluid in an amount based on the estimated concentration of MEA to reduce the concentration of MEA in the fluid.

Abstract: A method of determining a condition within a wellbore. The method comprises introducing a tubular member in a wellbore extending through a subterranean formation, the tubular member comprising a downhole article including a deformable material disposed around a surface of the tubular member, electrically conductive elements dispersed within the deformable material. The method includes measuring at least one electrical property of the deformable material. At least one of water ingress into the wellbore or an amount of expansion of the deformable material is determined based on the at least one measured electrical property. Related downhole systems and other related methods are also disclosed.

Abstract: A filter membrane includes carbon nanotubes and carbon nitride nanoparticles. Inter-particle atomic interactions between the carbon nanotubes and the carbon nitride nanoparticles bind the carbon nanotubes and the carbon nitride nanoparticles together. A filter cartridge includes such a filter membrane disposed within an outer housing between a fluid inlet and a fluid outlet such that fluid passing through the outer housing between the fluid inlet and the fluid outlet passes through the filter membrane. Such filter membranes may be formed by dispersing carbon nanotubes and carbon nitride nanoparticles in a liquid to form a suspension, and passing the suspension through a filter to deposit the nanotubes and nanoparticles on the filter. Liquid may be filtered by causing the liquid to pass through such a filter membrane.

Abstract: A method of making a thin film substrate involves exposing carbon nanostructures to a crosslinker to crosslink the carbon nanostructures. The crosslinked carbon nanostructures are recovered and disposed on a support substrate. A thin film substrate includes crosslinked carbon nanostructures on a support substrate. The crosslinked carbon nanostructures have a crosslinker between the carbon nanostructures. A method of performing surface enhanced Raman spectroscopy (SERS) on a SERS-active analyte involves providing a SERS-active analyte on such a thin film substrate, exposing the thin film substrate to Raman scattering, and detecting the SERS-active analyte.

Abstract: A system and method for estimating a concentration of monoethanolamine (MEA) in a fluid. A substrate for supporting a sample of the fluid during testing includes a carbon nanotube mat layer, a silver nanowire layer disposed on the carbon nanotube mat layer, and a chemical enhancer layer disposed on the silver nanowire layer. A sample of the fluid is placed on the substrate, and the fluid sample is radiated with electromagnetic radiation at a selected energy level. A detector measures a Raman spectrum emitted from the sample in response to the electromagnetic radiation. A processor estimates the concentration of MEA in the sample from the Raman spectrum and adds a corrosion inhibitor to the fluid in an amount based on the estimated concentration of MEA to reduce the concentration of MEA in the fluid.

Abstract: A system and method for estimating a concentration of monoethanolamine (MEA) in a fluid. A substrate for supporting a sample of the fluid during testing includes a carbon nanotube mat layer, a silver nanowire layer disposed on the carbon nanotube mat layer, and a chemical enhancer layer disposed on the silver nanowire layer. A sample of the fluid is placed on the substrate, and the fluid sample is radiated with electromagnetic radiation at a selected energy level. A detector measures a Raman spectrum emitted from the sample in response to the electromagnetic radiation. A processor estimates the concentration of MEA in the sample from the Raman spectrum and adds a corrosion inhibitor to the fluid in an amount based on the estimated concentration of MEA to reduce the concentration of MEA in the fluid.

Abstract: A method and apparatus for estimating a concentration of chemicals in a fluid flowing in a fluid passage is disclosed. A sample of the fluid is placed on a substrate comprising a first layer of carbon nanotubes and a second layer of metal nanowires. An energy source radiates the fluid sample with electromagnetic radiation at a selected energy level, and a detector measures an energy level of radiation emitted from the fluid sample in response to the electromagnetic radiation. A processor determines a Raman spectrum of the fluid sample from the energy level of the emitted radiation and estimates the concentration of a selected chemical in the fluid sample based on the Raman spectrum.

Abstract: A method of determining a condition within a wellbore. The method comprises introducing a tubular member in a wellbore extending through a subterranean formation, the tubular member comprising a downhole article including a deformable material disposed around a surface of the tubular member, electrically conductive elements dispersed within the deformable material. The method includes measuring at least one electrical property of the deformable material. At least one of water ingress into the wellbore or an amount of expansion of the deformable material is determined based on the at least one measured electrical property. Related downhole systems and other related methods are also disclosed.

Abstract: A deformable downhole article for use in a wellbore includes a tubular component configured for placement in a wellbore, a deformable material disposed around an outer surface of the tubular component, and an electrically conductive element comprising a carbon nanotube (CNT) material bonded to the deformable material. To form such a deformable downhole article, a deformable material is disposed around an outer surface of a tubular component, and an electrically conductive element comprising a carbon nanotube (CNT) material is bonded to the deformable material. In use, the deformable downhole article may be positioned within a wellbore, and the deformable material may be expanded to an expanded state. Expansion of the deformable material may strain the carbon nanotube (CNT) material of the electrically conductive element, and an electrical property of the electrically conductive element may be measured to deduce information about the state of the deformable material.

Abstract: A deformable downhole article for use in a wellbore includes a tubular component configured for placement in a wellbore, a deformable material disposed around an outer surface of the tubular component, and an electrically conductive element comprising a carbon nanotube (CNT) material bonded to the deformable material. To form such a deformable downhole article, a deformable material is disposed around an outer surface of a tubular component, and an electrically conductive element comprising a carbon nanotube (CNT) material is bonded to the deformable material. In use, the deformable downhole article may be positioned within a wellbore, and the deformable material may be expanded to an expanded state. Expansion of the deformable material may strain the carbon nanotube (CNT) material of the electrically conductive element, and an electrical property of the electrically conductive element may be measured to deduce information about the state of the deformable material.