Abstract: An overmoded dielectric-lined waveguide, particularly for the 0.03 to 3 terahertz frequency range, is disclosed with performance advantages relative to prior dielectric-lined waveguides, cost and size advantages relative to corrugated waveguides, and with coupling, bandwidth, and cost advantages relative to micro-structured-fiber waveguides. It comprises a single-clad flexible microwave laminate rolled into a cylinder with its copper surface outward and its dielectric surface facing inward. The rolled laminate is supported inside a metal tube. The same method of achieving the structure needed for efficient guiding of HE11 mode may be applied to a conical tube to make a low-cost efficient overmoded tapered waveguide transition for the 0.03-3 THz range.

Abstract: An improved method of supplying pressurized cold gas consistently of predominately N2 and He at low flow rate (typically under 1 g/s) with a desired N2 liquid fraction to an instrument requiring such is disclosed. Pressurized ultra-dry nitrogen gas of a controlled mass-flow rate is cooled inside fine coils bathed in liquid nitrogen to condense it to a vapor fraction less than about 20% and typically under 3%. A second gas stream consisting of predominately nitrogen plus helium, supplied from a controlled pressure, is cooled in a separate set of coils to an exit mean temperature significantly above the temperature of saturated nitrogen vapor in this mixture. The fluid from the first (condensed) mixture is injected into the cooled gas from the second mixture and transferred through a thermally insulated line to the input of the instrument needing a supply of cold gas of a target vapor fraction.

Abstract: An improved method of supplying pressurized cold gas consistently of predominately N2 and He at low flow rate (typically under 1 g/s) with a desired N2 liquid fraction to an instrument requiring such is disclosed. Pressurized ultra-dry nitrogen gas of a controlled mass-flow rate is cooled inside fine coils bathed in liquid nitrogen to condense it to a vapor fraction less than about 20% and typically under 3%. A second gas stream consisting of predominately nitrogen plus helium, supplied from a controlled pressure, is cooled in a separate set of coils to an exit mean temperature significantly above the temperature of saturated nitrogen vapor in this mixture. The fluid from the first (condensed) mixture is injected into the cooled gas from the second mixture and transferred through a thermally insulated line to the input of the instrument needing a supply of cold gas of a target vapor fraction.

Abstract: A liquid-loop compound recuperator is disclosed for high-? heat exchange between a first shell-side fluid stream and a second shell-side fluid stream of similar thermal capacity rates (W/K). The compound recuperator is comprised of at least two fluid-to-liquid (FL) recuperator modules for transfer of heat from a shell-side fluid, usually a gas, to an intermediary tube-side heat transfer liquid (HTL). Each FL module includes a plurality of thermally isolated, serially connected, adjacent exchanger cores inside a pressure vessel. The cores are rows of finned tubes for cross-flow transfer of heat, and they are arranged in series to effectively achieve counterflow exchange between the HTL and the shell-side stream. The HTL may be water, an organic liquid, a molten alloy, or a molten salt. Alumina-dispersion-strengthened-metal fins, superalloy tubes, and a lead-bismuth-tin alloy HTL may be used for high temperatures. Cumene may be used as the HTL in cryogenic applications.

Abstract: A Renewable Fischer Tropsch Synthesis (RFTS) process is disclosed for producing hydrocarbons and alcohol fuels from wind energy, waste CO2 and water. The process includes (A) electrolyzing water to generate hydrogen and oxygen, (B) generating syngas in a reverse water gas shift (RWGS) reactor, (C) driving the RWGS reaction to the right by condensing water from the RWGS products and separating CO using a CuAlCl4-aromatic complexing method, (D) using a compressor with variable stator nozzles, (E) carrying out the FTS reactions in a high-temperature multi-tubular reactor, (F) separating the FTS products using high-pressure fractional condensation, (G) separating CO2 from product streams for recycling through the RWGS reactor, and (H) using control methods to maintain the temperatures of the reactors, electrolyzer, and condensers at optima that are functions of the flow rate. The RFTS process may also include heat engines, a refrigeration cycle utilizing compressed oxygen, and a dual-source organic Rankine cycle.

Abstract: In a dual-source organic Rankine cycle (DORC), the condensed and slightly sub-cooled working fluid at near ambient temperature (˜300 K) and at low-side pressure (0.1 to 0.7 MPa) is (1) pumped to high-side pressure (0.5-5 MPa), (2) pre-heated in a low-temperature (LT) recuperator, (3) boiled using a low-grade heat source, (4) super-heated in a high-temperature (HT) recuperator to a temperature close to the expander turbine exhaust temperature using this exhaust vapor enthalpy, (5) further super-heated to the turbine inlet temperature (TIT) using a mid-grade heat source, (6) expanded through a turbine expander to the low-side pressure, (7) cooled through the HT recuperator, (8) cooled through the LT recuperator, (9) mostly liquefied and slightly subcooled in a condenser, and (10) the condensed portion is returned to the pump to repeat this cycle.

Abstract: All critical circuit components, including the sample coils, are located along with the spinner assembly in a region that may be evacuated to high vacuum for thermal insulation and high-voltage operation. A hermetically sealed spinner assembly simultaneously satisfies the requirements of hermeticity, low total emissivity, rf compatibility, spinning performance, magnetic compatibility, and high filling factor by utilizing metal construction except for the central region near the rf sample coils. Hence, it is possible to maintain high vacuum in the region external to the MAS spinner assembly even over a broad range of bearing and drive gas temperatures. A bundle of optical fibers is provided for tachometry for spin rates up to 60 kHz. The use of alumina disc capacitors allows the noise contributions from the most critical capacitors to be reduced to a minor fraction of the total and simplifies high voltage operation.

Abstract: In a dual-source organic Rankine cycle (DORC), the condensed and slightly sub-cooled working fluid at near ambient temperature (˜300 K) and at low-side pressure (0.1 to 0.7 MPa) is (1) pumped to high-side pressure (0.5-5 MPa), (2) pre-heated in a low-temperature (LT) recuperator, (3) boiled using a low-grade heat source, (4) super-heated in a high-temperature (HT) recuperator to a temperature close to the expander turbine exhaust temperature using this exhaust vapor enthalpy, (5) further super-heated to the turbine inlet temperature (TIT) using a mid-grade heat source, (6) expanded through a turbine expander to the low-side pressure, (7) cooled through the HT recuperator, (8) cooled through the LT recuperator, (9) mostly liquefied and slightly subcooled in a condenser, and (10) the condensed portion is returned to the pump to repeat this cycle.

Abstract: A Renewable Fischer Tropsch Synthesis (RFTS) process produces hydrocarbons and alcohol fuels from wind energy, waste CO2 and water. The process includes (A) electrolyzing water to generate hydrogen and oxygen, (B) generating syngas in a reverse water gas shift (RWGS) reactor, (C) driving the RWGS reaction to the right by condensing water from the RWGS products and separating CO using a CuAlCl4-aromatic complexing method, (D) using a compressor with variable stator nozzles, (E) carrying out the FTS reactions in a high-temperature multi-tubular reactor, (F) separating the FTS products using high-pressure fractional condensation, (G) separating CO2 from product streams for recycling through the RWGS reactor, and (H) using control methods to maintain temperatures of the reactors, electrolyzer, and condensers at optima that are functions of the flow rate. The RFTS process may also include heat engines, a refrigeration cycle utilizing compressed oxygen, and a dual-source organic Rankine cycle.

Abstract: A liquid-loop compound recuperator is disclosed for high-? heat exchange between a first shell-side fluid stream and a second shell-side fluid stream of similar thermal capacity rates (W/K). The compound recuperator is comprised of at least two fluid-to-liquid (FL) recuperator modules for transfer of heat from a shell-side fluid, usually a gas, to an intermediary tube-side heat transfer liquid (HTL). Each FL module includes a plurality of thermally isolated, serially connected, adjacent exchanger cores inside a pressure vessel. The cores are rows of finned tubes for cross-flow transfer of heat, and they are arranged in series to effectively achieve counterflow exchange between the HTL and the shell-side stream. The HTL may be water, an organic liquid, a molten alloy, or a molten salt.

Abstract: All critical circuit components, including the sample coils, are located along with the spinner assembly in a region that may be evacuated to high vacuum for thermal insulation and high-voltage operation. A hermetically sealed spinner assembly simultaneously satisfies the requirements of hermeticity, low total emissivity, rf compatibility, spinning performance, magnetic compatibility, and high filling factor by utilizing metal construction except for the central region near the rf sample coils. Hence, it is possible to maintain high vacuum in the region external to the MAS spinner assembly even over a broad range of bearing and drive gas temperatures. A bundle of optical fibers is provided for tachometry for spin rates up to 60 kHz. The use of alumina disc capacitors allows the noise contributions from the most critical capacitors to be reduced to a minor fraction of the total and simplifies high voltage operation.

Abstract: An NMR probe contains a metallic dewar for use in a high field magnet, the dewar characterized as having a major fraction of its inner wall made from an alloy whose weight composition includes at least 70% copper, less than 20% zinc, less than 10% nickel, less than 8% Cr, less than 4% Pb, less than 0.15% iron, less than 0.15% cobalt, and at least 3% from the set comprised of tin, silicon, aluminum, and chromium, and said inner wall further characterized as being plated with a pure metal on at least one surface.

Abstract: An NMR probe contains a metallic dewar for use in a high field magnet, the dewar characterized as having a major fraction of its inner wall made from an alloy whose weight composition includes at least 70% copper, less than 20% zinc, less than 10% nickel, less than 8% Cr, less than 4% Pb, less than 0.15% iron, less than 0.15% cobalt, and at least 3% from the set comprised of tin, silicon, aluminum, and chromium, and said inner wall further characterized as being plated with a pure metal on at least one surface.

Abstract: The MRI rf coil known as the balanced high-pass-weighted hybrid birdcage is modified to obtain two homogeneous degenerate resonances, capable of generating circular polarization at widely separated frequencies, by including inductors in parallel with the ring (high-pass) tuning capacitors such that their isolated parallel resonant frequency is greater than the desired low-frequency (LF) homogeneous resonance and not greater than 10% more than the desired high-frequency (HF) homogeneous resonance. The coil is advantageous for the frequency-diameter product range of 10 to 60 MHz-m. The coil is preferably balanced at both frequencies such that the electric potentials vanish on the central axial plane at both the LF and HF homogeneous modes. Additional parasitic-mode-shifting reactive elements, either capacitors or inductors, may be added between adjacent rungs near their ends, and the rungs may each consist of two parallel bands shorted together at their ends, as in the Crozier birdcage.

Abstract: “An MAS probe is disclosed for obtaining a substantial improvement in signal to noise (S/N) in triple-resonance high-resolution (HR) magic-angle-spinning (MAS) NMR of samples near room temperature (RT) in high-field magnets where the magnet's RT shim bore is greater than 60 mm. All critical circuit components, including the sample coils, are located along with the spinner assembly in a thermally insulated cold zone pressurized with helium gas. The spinner assembly attaches to a sealed, curved, rotor-loading tube to permit automatic sample change, and it is surrounded by a partially insulated jacket cooled with a cryogenic fluid, generally nitrogen gas. The MAS probe is also compatible with magic angle gradients, variable temperature operation, field locking, and commonly available closed-cycle cold fingers.

Abstract: A material having a permanent external diametrical electric field is included within an NMR MAS spinner. Such materials include ferroelectret porous films, in which the electric polarization arises from opposite mono-polar charges on separated surfaces within a structured material containing voids. Rotation of electrically polarized material produces a time-dependent electric field, modulated at the rotational frequency, so that a simple antenna achieves high sensitivity and phase stability in spin rate detection. The electrically polarized material is also of sufficiently high resistivity that modulation of the external NMR polarizing magnetic field B0 is negligible.

Abstract: An improved axial gas bearing for a gas-driven NMR MAS sample rotor is disclosed that utilizes inward flow with a low rotational component over a rotor conical end. A conical flow region is formed between the rotor conical end and a conical stator bearing surface such that the included angle defining the stator surface is not less than the included angle defining the rotor conical end. Gas is injected radially inward with a significant axial rearward component from a number of small holes at high velocity from the periphery into the conical flow region. Compared to the radial velocity components, the tangential flow components of the injected gas are small and preferably opposed to the direction of the rotor rotation.

Abstract: A MAS probe offers a substantial improvement in signal to noise (S/N) in triple-resonance high-resolution (HR) magic-angle-spinning (MAS) NMR of samples near room temperature (RT) in high field magnets, especially where the RT shim bore is less than 55 mm. Critical circuit components other than the sample coils, including both high-power capacitors and inductors for one or more channels are located in a small, thermally insulated, cold zone immediately below the sample spinner assembly. Cooling these components to 100 K allows their thermal noise power to be conveniently reduced by a factor of three or more. Variable capacitors for fine tuning are located in an RT tuning zone below the cold zone. The circuit is designed such that the currents, voltages, and standing wave ratio (SWR) in circuit tuning elements in the RT tuning zone are relatively low, so rf losses and noise contributions below the cold zone may be only a few percent.

Abstract: A flexible, low-loss, low-capacitance, high-voltage, high-current, moderate-impedance, unshielded, balanced, rf-pulse transmission twinline is produced by etching parallel copper traces on opposite sides of a flexible substrate, spaced apart such that the distance between the conductors is greater than four times the substrate thickness and at least one of the conductors has a width greater than half of the separation between the conductors. A second, similar twinline may be etched on the same substrate beside the first twinline and paralleled at both ends with the first twinline to form a lower-impedance quadline such that alternate conductors in the quadline are on alternate sides of the substrate and have opposite current phases. Both surfaces may be coated with a thin, flexible dielectric to increase the voltage rating for a given conductor separation with minimal affect on propagation factor, attenuation constant, or flexibility.

Abstract: The two halves of a conventional RF saddle coil, such as spirals or other related structures for use in high resolution NMR or MRI, are disposed on opposite sides of a cylindrical coilform, and rotated from the conventional orientation 90 degrees about the B1 axis, so that the leads are paralleled near the axial center of the RF coil.