Abstract: Described herein is a crosslinked graphene and biopolymer (e.g. lignin) based composite membrane that provides selective resistance for solutes while providing water permeability. The membrane may include optional additional functional additives in a crosslinked material matrix that provides enhanced salt separation from water. Methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Abstract: Described herein are crosslinked graphene oxide and polycarboxylic acid based composite membranes that provide selective resistance for gases while providing water vapor permeability. Such composite membranes have a high water/air selectivity in permeability. The methods for making such membranes, and using the membranes for dehydrating or removing water vapor from gases are also described.

Abstract: Described herein is a crosslinked graphene based composite membrane that provides selective resistance to fluids solutes while providing water permeability, such as a selectively permeable membrane comprising a crosslinked graphene with a polyvinyl alcohol and silica-nanoparticle layer that can provide enhanced water separation. Also described herein are methods for making such membranes and methods of using the membranes for dehydrating or removing solutes from water.

Abstract: Described herein are crosslinked graphene oxide and polycaroxylic acid based composite membranes that provide selective resistance for solutes while providing water permeability. Such composite membranes have a high water flux. The methods for making such membranes, and using the membranes for dehydrating or removing solutes from water are also described.

Abstract: Described herein are protective coatings for reverse osmosis membranes comprising coating mixtures of graphene oxide crosslinked with copolymers. The crosslinked GO copolymer mixture coatings provide protection from chlorine-based defoulers of saline water and unprocessed fluids. The coated membranes described herein create a reverse osmosis structure that has excellent water flux and salt rejection. The crosslinking copolymers can comprise an optionally substituted vinyl imidazole constituent unit and an optionally substituted acrylic amide constituent unit.

Abstract: Described herein is a graphene and polyvinyl alcohol based multilayer composite membrane that provides selective resistance for solutes to pass the membrane while providing water permeability. A selectively permeable membrane comprising a crosslinked graphene with a polyvinyl alcohol and silica-nanoparticle layer that can provide enhanced salt separation from water, methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Abstract: Described herein is a crosslinked graphene and biopolymer (e.g. lignin) based composite membrane that provides selective resistance for solutes while providing water permeability. The membrane may include optional additional functional additives in a crosslinked material matrix that provides enhanced salt separation from water. Methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Abstract: Described herein is a graphene material-based membrane that provides selective resistance for solutes or gas while providing water permeability. A selectively permeable membrane comprising graphene oxide, reduced graphene oxide, and also functionalized or crosslinked between the graphene, that provides enhanced salt separation from water or gas permeability resistance, methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Abstract: Described herein is a graphene and polyvinyl alcohol based multilayer composite membrane that provides selective resistance for solutes to pass through the membrane while providing water permeability. A selectively permeable membrane comprising a crosslinked graphene with a polyvinyl alcohol and an additive that can provide enhanced salt separation from water, methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Abstract: Described herein is a graphene material based membrane that provides selective resistance for solutes or gas while providing water permeability. A selectively permeable membrane comprising graphene oxide, reduced graphene oxide, and also functionalized or crosslinked between the graphene, that provides enhanced salt separation from water or gas permeability resistance, methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Abstract: Described herein is a graphene material based membrane that provides selective resistance for solutes or gas while providing water permeability. A selectively permeable membrane comprising graphene oxide, reduced graphene oxide, and also functionalized or crosslinked between the graphene, that provides enhanced salt separation from water or gas permeability resistance, methods for making such membranes, and methods of using the membranes for dehydrating or removing solutes from water are also described.

Abstract: A downhole drilling vibration analysis involves measuring orientation data in at least two orthogonal axes downhole while drilling with a drilling assembly. For example, two orthogonal magnetometers can be used. A toolface of the drilling assembly is determined using the measured sensor data, and velocity (RPM) values for the toolface for a plurality of revolutions of the drilling assembly are determined. From these determined values, a coefficient of variation for the toolface velocity (RPM) values for the revolutions of the drilling assembly is calculated. When a pattern in found in the toolface velocity (RPM) and/or the calculated coefficient of variations exceed one or more thresholds, the processing device determines that detrimental vibrations are occurring in the drilling assembly.

Abstract: A downhole drilling vibration analysis involves measuring orientation data in at least two orthogonal axes downhole while drilling with a drilling assembly. For example, two orthogonal magnetometers can be used. A toolface of the drilling assembly is determined using the measured sensor data, and velocity (RPM) values for the toolface for a plurality of revolutions of the drilling assembly are determined. From these determined values, a coefficient of variation for the toolface velocity (RPM) values for the revolutions of the drilling assembly is calculated. When a pattern in found in the toolface velocity (RPM) and/or the calculated coefficient of variations exceed one or more thresholds, the processing device determines that detrimental vibrations are occurring in the drilling assembly.

Abstract: A downhole drilling vibration analysis involves measuring orientation data in at least two orthogonal axes downhole while drilling with a drilling assembly. For example, two orthogonal magnetometers can be used. A toolface of the drilling assembly is determined using the measured sensor data, and velocity (RPM) values for the toolface for a plurality of revolutions of the drilling assembly are determined. From these determined values, a coefficient of variation for the toolface velocity (RPM) values for the revolutions of the drilling assembly is calculated. When a pattern in found in the toolface velocity (RPM) and/or the calculated coefficient of variations exceed one or more thresholds, the processing device determines that detrimental vibrations are occurring in the drilling assembly.

Abstract: A cross-flow filtration apparatus is provided. The cross-flow filter is a spiral wound filter that includes a semi-permeable membrane wrapped around a perforated central tube. The semi-permeable membrane includes a feed spacer and a membrane. The feed spacer is a biocidal feed spacer with a biocidal agent impregnated within the feed spacer to prevent biofouling of the feed spacer and the membrane.

Abstract: A directional sensor system that incorporates a single axis sensor element that is manipulated to a plurality of orientations. The resulting responses of the sensor element at these locations are combined to obtain a measure of orientation of the system. The system applicable for determining orientation of instrumentation within a well borehole such as measurement-while-drilling, wireline and tubing conveyed borehole instrumentation. The system can be used in other subsurface and surface applications.

Abstract: A resistivity tool for use in an LWD system includes an asymmetric transmitter design with multiple transmitters capable of generating EM signals at multiple frequencies. A pair of receivers are positioned at one end of the transmitter array to detect the EM signals after they have traversed the region in the vicinity of the borehole. A calibrating transmitter is positioned between the receivers, which can be used in two different modes of operation. In a first mode, the calibrating transmitter is used to calibrate the receivers for thermal drift. In this calibration mode, an attenuation correction and phase shift correction can be calculated to correct for thermal drift of the receivers while the resistivity tool is in the borehole. Thus, the thermal drift of the receivers can be re-calibrated as often as desired while the tool is in the well. In a second mode of operation, the calibrating receiver may be used to measure the resistivity of the drilling mud in the borehole.