Development of Balanced SIS Mixers for ALMA Band-10

NASA Astrophysics Data System (ADS)

Shitov, Sergey V.; Koryukin, Oleg V.; Uzawa, Yoshinory; Noguchi, Takashi; Uvarov, Andrey V.; Cohn, Ilya A.

2006-05-01

A few concepts of a wide-band balanced SIS mixer employing submicron-sized SIS junctions are under development for 787-950 GHz frequency range. A quasioptical DSB balanced mixer with integrated cross-slot antenna is considered as the less laborious and cheaper option. The silicon lens-antenna beam efficiency is expected above 80 % across the whole band with first-order sidelobe below -16 dB. To use the conservative horn antenna solution, a single chamber waveguide DSB balanced mixer is developed. Two equal probe-type SIS chips are inserted into a full-height waveguide through its opposite broad walls; these two mixers are driven by the signal waveguide in series. The LO current is transferred to the mixers in parallel via a capacitive probe inserted through the narrow wall of the signal waveguide from the neighboring LO waveguide. The HFSS model demonstrated the LO power coupling efficiency above -3 dB, almost perfect signal transfer and the LO cross talk below -30 dB that take into account misalignment (misbalance) of the chips. It is demonstrated numerically using Tucker's 3-port model that unequal pump of junctions of a twin-SIS mixer can lead, in spite of the perfect signal coupling, to degradation of the gain performance up to -3 dB, especially at the top of the ALMA Band-10.

Organic flash cycles for efficient power production

DOEpatents

Ho, Tony; Mao, Samuel S.; Greif, Ralph

2016-03-15

This disclosure provides systems, methods, and apparatus related to an Organic Flash Cycle (OFC). In one aspect, a modified OFC system includes a pump, a heat exchanger, a flash evaporator, a high pressure turbine, a throttling valve, a mixer, a low pressure turbine, and a condenser. The heat exchanger is coupled to an outlet of the pump. The flash evaporator is coupled to an outlet of the heat exchanger. The high pressure turbine is coupled to a vapor outlet of the flash evaporator. The throttling valve is coupled to a liquid outlet of the flash evaporator. The mixer is coupled to an outlet of the throttling valve and to an outlet of the high pressure turbine. The low pressure turbine is coupled to an outlet of the mixer. The condenser is coupled to an outlet of the low pressure turbine and to an inlet of the pump.

Aeroacoustic Characteristics of a Rectangular Multi-Element Supersonic Jet Mixer-Ejector Nozzle

NASA Technical Reports Server (NTRS)

Raman, Ganesh; Taghavi, Ray

1996-01-01

This paper provides a unique, detailed evaluation of the acoustics and aerodynamics of a rectangular multi-element supersonic jet mixer-ejector noise suppressor. The performance of such mixer-ejectors is important in aircraft engine application for noise suppression and thrust augmentation. In contrast to most prior experimental studies on ejectors that reported either aerodynamic or acoustic data, our work documents both types of data. We present information on the mixing, pumping, ejector wall pressure distribution, thrust augmentation and noise suppression characteristics of four simple, multi-element, jet mixer-ejector configurations. The four configurations included the effect of ejector area ratio (AR = ejector area/primary jet area) and the effect of non-parallel ejector walls. We also studied in detail the configuration that produced the best noise suppression characteristics. Our results show that ejector configurations that produced the maximum maximum pumping (entrained flow per secondary inlet area) also exhibited the lowest wall pressures in the inlet region, and the maximum thrust augmentation. When cases having the same total mass flow were compared, we found that noise suppression trends corresponded with those for pumping. Surprisingly, the mixing (quantified by the peak Mach number, and flow uniformity) at the ejector exit exhibited no relationship to the noise suppression at moderate primary jet fully expanded Mach numbers (Mj is less than 1.4). However, the noise suppression dependence on the mixing was apparent at higher Mj. The above observations are justified by noting that the mixing at the ejector exit is ot a strong factor in determining the radiated noise when noise produced internal to the ejector dominates the noise field outside the ejector.

All-solid-state radiometers for environmental studies to 700 GHz

NASA Technical Reports Server (NTRS)

Zimmermann, Ralph; Zimmermann, Ruediger; Zimmermann, Peter

1992-01-01

We report results with an all-solid-state radiometer for measurements of the ClO molecule at 649 GHz. The project is part of a program to provide low-noise, low-weight, low-power radiometers for space operation, and special effort has been expended on the development of high-efficiency solid-state frequency multipliers and Schottky-barrier mixers with low local oscillator power requirements. The best measured system noise temperature was 1750 K with the mixer and preamplifier cooled to 77 K. The mixer diode was easily pumped into saturation, indicating that the design has excellent prospects of operating at higher frequencies - our present design goal being 1 THz. We comment on the principal design features of such systems and will report on stratospheric measurements performed with this system.

Passive micromixer using by convection and surface tension effects with air-liquid interface.

PubMed

Ju, Jongil; Warrick, Jay

2013-12-01

This article describes a passive micromixer that utilizes an air-liquid interface and surface tension effects to enhance fluid mixing via convection and Marangoni effects. Performance of the microfluidic component is tested within a passive-pumping-based device that consists of three microchannels connected in succession using passive micro-mixers. Mixing was quantified at 5 key points along the length of the device using microscope images of patterned streams of Alexa 488 fluorescent-dyed water and pure DI water flowing through the device. The passive micro-mixer mixed fluid 15-20 times more effectively than diffusion between laminar flow streams alone and is a novel micro-mixer embodiment that provides an additional strategy for removing external components from microscale devices for simpler, autonomous operation.

Passive micromixer using by convection and surface tension effects with air-liquid interface

PubMed Central

Ju, Jongil; Warrick, Jay

2014-01-01

This article describes a passive micromixer that utilizes an air-liquid interface and surface tension effects to enhance fluid mixing via convection and Marangoni effects. Performance of the microfluidic component is tested within a passive-pumping-based device that consists of three microchannels connected in succession using passive micro-mixers. Mixing was quantified at 5 key points along the length of the device using microscope images of patterned streams of Alexa 488 fluorescent-dyed water and pure DI water flowing through the device. The passive micro-mixer mixed fluid 15–20 times more effectively than diffusion between laminar flow streams alone and is a novel micro-mixer embodiment that provides an additional strategy for removing external components from microscale devices for simpler, autonomous operation. PMID:25104979

A 0.2-0.5 THz single-band heterodyne receiver based on a photonic local oscillator and a superconductor-insulator-superconductor mixer

NASA Astrophysics Data System (ADS)

Kohjiro, Satoshi; Kikuchi, Kenichi; Maezawa, Masaaki; Furuta, Tomofumi; Wakatsuki, Atsushi; Ito, Hiroshi; Shimizu, Naofumi; Nagatsuma, Tadao; Kado, Yuichi

2008-09-01

We have demonstrated that a superconductor-insulator-superconductor (SIS) mixer pumped by a photonic local oscillator (LO) covers the whole frequency range of 0.2-0.5THz. In the bandwidth of 74% of the center frequency, this single-band receiver exhibits noise temperature of TRX⩽20hf/kB, where h is Planck's constant, f is the frequency, and kB is Boltzmann's constant. Resultant TRX is almost equal to TRX of the identical SIS mixer pumped by three conventional frequency-multiplier-based LOs which share the 0.2-0.5THz band. This technique will contribute to simple, wide-band, and low-noise heterodyne receivers in the terahertz region.

Remotely powered distributed microfluidic pumps and mixers based on miniature diodes.

PubMed

Chang, Suk Tai; Beaumont, Erin; Petsev, Dimiter N; Velev, Orlin D

2008-01-01

We demonstrate new principles of microfluidic pumping and mixing by electronic components integrated into a microfluidic chip. The miniature diodes embedded into the microchannel walls rectify the voltage induced between their electrodes from an external alternating electric field. The resulting electroosmotic flows, developed in the vicinity of the diode surfaces, were utilized for pumping or mixing of the fluid in the microfluidic channel. The flow velocity of liquid pumped by the diodes facing in the same direction linearly increased with the magnitude of the applied voltage and the pumping direction could be controlled by the pH of the solutions. The transverse flow driven by the localized electroosmotic flux between diodes oriented oppositely on the microchannel was used in microfluidic mixers. The experimental results were interpreted by numerical simulations of the electrohydrodynamic flows. The techniques may be used in novel actively controlled microfluidic-electronic chips.

System Description for Tank 241-AZ-101 Waste Retrieval Data Acquisition System

DOE Office of Scientific and Technical Information (OSTI.GOV)

ROMERO, S.G.

2000-01-10

Describes the hardware and software for the AZ-101 Mixer Pump Data Acquisition System. The purpose of the tank 241-AZ-101 retrieval system Data Acquisition System (DAS) is to provide monitoring and data acquisition of key parameters in order to confirm the effectiveness of the mixer pumps utilized for suspending solids in the tank. The suspension of solids in Tank 241-AZ-101 is necessary for pretreatment of the neutralized current acid waste (NCAW), and eventual disposal as glass via the Hanford Waste Vitrification Plant.

Compact Receiver Front Ends for Submillimeter-Wave Applications

NASA Technical Reports Server (NTRS)

Mehdi, Imran; Chattopadhyay, Goutam; Schlecht, Erich T.; Lin, Robert H.; Sin, Seth; Peralta, Alejandro; Lee, Choonsup; Gill, John J.; Gulkis, Samuel; Thomas, Bertrand C.

2012-01-01

The current generation of submillimeter-wave instruments is relatively mass and power-hungry. The receiver front ends (RFEs) of a submillimeter instrument form the heart of the instrument, and any mass reduction achieved in this subsystem is propagated through the instrument. In the current implementation, the RFE consists of different blocks for the mixer and LO circuits. The motivation for this work is to reduce the mass of the RFE by integrating the mixer and LO circuits in one waveguide block. The mixer and its associated LO chips will all be packaged in a single waveguide package. This will reduce the mass of the RFE and also provide a number of other advantages. By bringing the mixer and LO circuits close together, losses in the waveguide will be reduced. Moreover, the compact nature of the block will allow for better thermal control of the block, which is important in order to reduce gain fluctuations. A single waveguide block with a 600- GHz RFE functionality (based on a subharmonically pumped Schottky diode pair) has been demonstrated. The block is about 3x3x3 cubic centimeters. The block combines the mixer and multiplier chip in a single package. 3D electromagnetic simulations were carried out to design the waveguide circuit around the mixer and multiplier chip. The circuit is optimized to provide maximum output power and maximum bandwidth. An integrated submillimeter front end featuring a 520-600-GHz sub-harmonic mixer and a 260-300-GHz frequency tripler in a single cavity was tested. Both devices used GaAs MMIC membrane planar Schottky diode technology. The sub-harmonic mixer/tripler circuit has been tested using conventional metal-machined blocks. Measurement results on the metal block give best DSB (double sideband) mixer noise temperature of 2,360 K and conversion losses of 7.7 dB at 520 GHz. The LO input power required to pump the integrated tripler/sub-harmonic mixer is between 30 and 50 mW.

Apparatus and method for gelling liquefied gasses

NASA Technical Reports Server (NTRS)

Elliott, Adam (Inventor); DiSalvo, Roberto (Inventor); Shepherd, Phillip (Inventor); Kosier, Ryan (Inventor)

2011-01-01

A method and apparatus for gelling liquid propane and other liquefied gasses includes a temperature controlled churn mixer, vacuum pump, liquefied gas transfer tank, and means for measuring amount of material entering the mixer. The apparatus and method are particularly useful for the production of high quality rocket fuels and propellants.

Tunable All-Solid-State Local Oscillators to 1900 GHz

NASA Technical Reports Server (NTRS)

Ward, John; Chattopadhyay, Goutam; Maestrini, Alain; Schlecht, Erich; Gill, John; Javadi, Hamid; Pukala, David; Maiwald, Frank; Mehdi, Imran

2004-01-01

We present a status report of an ongoing effort to develop robust tunable all-solid-state sources up to 1900 GHz for the Heterodyne Instrument for the Far Infrared (HIFI) on the Herschel Space Observatory. GaAs based multi-chip power amplifier modules at W-band are used to drive cascaded chains of multipliers. We have demonstrated performance from chains comprised of four doublers up to 1600 GHz as well as from a x2x3x3 chain to 1900 GHz. Measured peak output power of 23 (micro)W at 1782 GHz and 2.6 (micro)W at 1900 GHz has been achieved when the multipliers are cooled to 120K. The 1900 GHz tripler was pumped with a four anode tripler that produces a peak of 4 mW at 630 GHz when cooled to 120 K. We believe that these sources can now be used to pump hot electron bolometer (HEB) heterodyne mixers.ter (HEB) heterodyne mixers.

Submersible canned motor mixer pump

DOEpatents

Guardiani, R.F.; Pollick, R.D.

1997-10-07

A mixer pump is described used in a waste tank for mobilizing high-level radioactive liquid waste having a column assembly containing power cables, a motor housing with electric motor means which includes a stator can of a stator assembly and a rotor can of a rotor assembly, and an impeller assembly with an impeller connected to a shaft of the rotor assembly. The column assembly locates the motor housing with the electric motor means adjacent to the impeller which creates an hydraulic head, and which forces the liquid waste into the motor housing to cool the electric motor means and to lubricate radial and thrust bearing assemblies. Hard-on-hard bearing surfaces of the bearing assemblies and a ring assembly between the impeller and electric motor means act to grind down large particles in the liquid waste flow. These larger particles are received in slots in the static bearing members of the radial bearing assemblies. Only solid waste particles smaller than the clearances in the system can pass there through, thereby resisting damage to and the interruption of the operation of the mixer pump. 10 figs.

Submersible canned motor mixer pump

DOEpatents

Guardiani, Richard F.; Pollick, Richard D.

1997-01-01

A mixer pump used in a waste tank for mobilizing high-level radioactive liquid waste having a column assembly containing power cables, a motor housing with electric motor means which includes a stator can of a stator assembly and a rotor can of a rotor assembly, and an impeller assembly with an impeller connected to a shaft of the rotor assembly. The column assembly locates the motor housing with the electric motor means adjacent to the impeller which creates an hydraulic head, and which forces the liquid waste into the motor housing to cool the electric motor means and to lubricate radial and thrust bearing assemblies. Hard-on-hard bearing surfaces of the bearing assemblies and a ring assembly between the impeller and electric motor means act to grind down large particles in the liquid waste flow. These larger particles are received in slots in the static bearing members of the radial bearing assemblies. Only solid waste particles smaller than the clearances in the system can pass therethrough, thereby resisting damage to and the interruption of the operation of the mixer pump.

5 Gbps wireless transmission link with an optically pumped uni-traveling carrier photodiode mixer at the receiver.

PubMed

Mohammad, Ahmad W; Shams, Haymen; Balakier, Katarzyna; Graham, Chris; Natrella, Michele; Seeds, Alwyn J; Renaud, Cyril C

2018-02-05

We report the first demonstration of a uni-traveling carrier photodiode (UTC-PD) used as a 5 Gbps wireless receiver. In this experiment, a 35.1 GHz carrier was electrically modulated with 5 Gbps non-return with zero on-off keying (NRZ-OOK) data and transmitted wirelessly over a distance of 1.3 m. At the receiver, a UTC-PD was used as an optically pumped mixer (OPM) to down-convert the received radio frequency (RF) signal to an intermediate frequency (IF) of 11.7 GHz, before it was down-converted to the baseband using an electronic mixer. The recovered data show a clear eye diagram, and a bit error rate (BER) of less than 10 -8 was measured. The conversion loss of the UTC-PD optoelectronic mixer has been measured at 22 dB. The frequency of the local oscillator (LO) used for the UTC-PD is defined by the frequency spacing between the two optical tones, which can be broadly tuneable offering the frequency agility of this photodiode-based receiver.

Quantum-limited detection of millimeter waves using superconducting tunnel junctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mears, Carl Atherton

1991-09-01

The quasiparticle tunneling current in a superconductor-insulator- superconductor (SIS) tunnel junction is highly nonlinear. Such a nonlinearity can be used to mix two millimeter wave signals to produce a signal at a much lower intermediate frequency. We have constructed several millimeter and sub-millimeter wave SIS mixers in order to study high frequency response of the quasiparticle tunneling current and the physics of high frequency mixing. We have made the first measurement of the out-of-phase tunneling currents in an SIS tunnel junction. We have developed a method that allows us to determine the parameters of the high frequency embedding circuit bymore » studying the details of the pumped I-V curve. We have constructed a 80--110 GHz waveguide-based mixer test apparatus that allows us to accurately measure the gain and added noise of the SIS mixer under test. Using extremely high quality tunnel junctions, we have measured an added mixer noise of 0.61 ± 0.36 quanta, which is within 25 percent of the quantum limit imposed by the Heisenberg uncertainty principle. This measured performance is in excellent agreement with that predicted by Tucker`s theory of quantum mixing. We have also studied quasioptically coupled millimeter- and submillimeter-wave mixers using several types of integrated tuning elements. 83 refs.« less

Quantum-limited detection of millimeter waves using superconducting tunnel junctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mears, C.A.

1991-09-01

The quasiparticle tunneling current in a superconductor-insulator- superconductor (SIS) tunnel junction is highly nonlinear. Such a nonlinearity can be used to mix two millimeter wave signals to produce a signal at a much lower intermediate frequency. We have constructed several millimeter and sub-millimeter wave SIS mixers in order to study high frequency response of the quasiparticle tunneling current and the physics of high frequency mixing. We have made the first measurement of the out-of-phase tunneling currents in an SIS tunnel junction. We have developed a method that allows us to determine the parameters of the high frequency embedding circuit bymore » studying the details of the pumped I-V curve. We have constructed a 80--110 GHz waveguide-based mixer test apparatus that allows us to accurately measure the gain and added noise of the SIS mixer under test. Using extremely high quality tunnel junctions, we have measured an added mixer noise of 0.61 {plus minus} 0.36 quanta, which is within 25 percent of the quantum limit imposed by the Heisenberg uncertainty principle. This measured performance is in excellent agreement with that predicted by Tucker's theory of quantum mixing. We have also studied quasioptically coupled millimeter- and submillimeter-wave mixers using several types of integrated tuning elements. 83 refs.« less

An Integrated 520-600 GHz Sub-Harmonic Mixer and Tripler Combination Based on GaAs MMIC Membrane Planar Schottky Diodes

NASA Technical Reports Server (NTRS)

Thomas, B.; Gill, J.; Maestrini, A.; Lee, C.; Lin, R.; Sin, S.; Peralta, A.; Mehdi, I.

2011-01-01

We present here the design, development and test of an integrated sub-millimeter front-end featuring a 520-600 GHz sub-harmonic mixer and a 260-300 GHz frequency tripler in a single cavity. Both devices used GaAs MMIC membrane planar Schottky diode technology. The sub-harmonic mixer/tripler circuit has been tested using conventional machined as well as silicon micro-machined blocks. Measurement results on the metal block give best DSB mixer noise temperature of 2360 K and conversion losses of 7.7 dB at 520 GHz. Preliminary results on the silicon micro-machined blocks give a DSB mixer noise temperature of 4860 K and conversion losses of 12.16 dB at 540 GHz. The LO input power required to pump the integrated tripler/sub-harmonic mixer for both packages is between 30 and 50 mW

An Integrated 520-600 GHz Sub-Harmonic Mixer and Tripler Combination Based on GaAs MMIC Membrane Planar Schottky Diodes

NASA Technical Reports Server (NTRS)

Thomas, B.; Gill, J.; Maestrini, A.; Lee, C.; Lin, R.; Sin, S.; Peralta, A.; Mehdi, I.

2010-01-01

We present here the design, development and test of an integrated sub-millimeter front-end featuring a 520-600 GHz sub-harmonic mixer and a 260-300 GHz frequency tripler in a single cavity. Both devices used GaAs MMIC membrane planar Schottky diode technology. The sub-harmonic mixer/tripler circuit has been tested using conventional machined as well as silicon micro-machined blocks. Measurement results on the metal block give best DSB mixer noise temperature of 2360 K and conversion losses of 7.7 dB at 520 GHz. Preliminary results on the silicon micro-machined blocks give a DSB mixer noise temperature of 4860 K and conversion losses of 12.16 dB at 540 GHz. The LO input power required to pump the integrated tripler/sub-harmonic mixer for both packages is between 30 and 50 mW.

3. Credit BG. The interior of the control room appears ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Credit BG. The interior of the control room appears in this view, looking north (0°). The control console in the room center permitted remote control of various propellant grinders and mixers in surrounding buildings. Television monitors (absent from their mounts in this view) permitted direct viewing of operating machinery. From foreground to background: Panel (1) contains OGAR warning light switches for Curing Buildings E-39, E-40, E-41 and E-86; (O=off, G=green safe, A=amber caution, R=red danger) Panel (2) E-85 Oxidizer Dryer Building console: OGAR switch Panel (3) E-84 Oxidizer Grinder Building console: controls for vibrator, feed, and hammer; Panel (4) E-36 Oxidizer Grinder Building console: controls for vibrator, feed, hammer, attritor, and SWECO ("SWECO" undefined) Panels (5) & (6) blank Panel (7) E-38 Mixer & Casting Building console: vacuum pump, blender, heating and cooling controls Panel (8) E-37 Mixer & Casting Building console: motor controls for 1 pint, 1 gallon, 5 gallon and 30 gallon mixers; vacuum pump, deluge (fire suppression), pot up/down, vibrator, feed, and SWECO. - Jet Propulsion Laboratory Edwards Facility, Weigh & Control Building, Edwards Air Force Base, Boron, Kern County, CA

A 220-GHz SIS Mixer Tightly Integrated With a Sub-Hundred-Microwatt SiGe IF Amplifier

NASA Astrophysics Data System (ADS)

Montazeri, Shirin; Grimes, Paul K.; Tong, Cheuk-Yu Edward; Bardin, Joseph C.

2016-01-01

Future kilopixel-scale heterodyne focal plane arrays based on superconductor-insulator-superconductor (SIS) mixers will require submilliwatt power consumption low-noise amplifiers (LNAs) which are tightly integrated with the mixers. In this paper, an LNA that is optimized for direct connection to a 220-GHz SIS mixer chip and requires less than 100 μW of dc power is reported. The amplifier design process is described, and measurement results are presented. It is shown that, when pumped at local oscillator frequencies between 214 and 226 GHz, the mixer/amplifier module achieves a double-sideband system noise temperature between 35 and 50 K over the 3.3-6 GHz IF frequency range while requiring just 90 μW of dc power. Moreover, the potential to further reduce the power consumption is explored and successful operation is demonstrated for LNA power consumption as low as 60 μW.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1999-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1998-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards of downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Thermodynamic Vent System Test in a Low Earth Orbit Simulation

NASA Technical Reports Server (NTRS)

VanOverbeke, Thomas J.

2004-01-01

A thermodynamic vent system for a cryogenic nitrogen tank was tested in a vacuum chamber simulating oxygen storage in low earth orbit. The nitrogen tank was surrounded by a cryo-shroud at -40 F. The tank was insulated with two layers of multi-layer insulation. Heat transfer into cryogenic tanks causes phase change and increases tank pressure which must be controlled. A thermodynamic vent system was used to control pressure as the location of vapor is unknown in low gravity and direct venting would be wasteful. The thermodynamic vent system consists of a Joule-Thomson valve and heat exchanger installed on the inlet side of the tank mixer-pump. The combination is used to extract thermal energy from the tank fluid, reducing temperature and ullage pressure. The system was sized so that the tank mixer-pump operated a small fraction of the time to limit motor heating. Initially the mixer used sub-cooled liquid to cool the liquid-vapor interface inducing condensation and pressure reduction. Later, the thermodynamic vent system was used. Pressure cycles were performed until steady-state operation was demonstrated. Three test runs were conducted at tank fills of 97, 80, and 63 percent. Each test was begun with a boil-off test to determine heat transfer into the tank. The lower tank fills had time averaged vent rates very close to steady-state boil-off rates showing the thermodynamic vent system was nearly as efficient as direct venting in normal gravity.

InGaAs/InP heteroepitaxial Schottky barrier diodes for terahertz applications

NASA Technical Reports Server (NTRS)

Bhapkar, Udayan V.; Li, Yongjun; Mattauch, Robert J.

1992-01-01

This paper explores the feasibility of planar, sub-harmonically pumped, anti-parallel InGaAs/InP heteroepitaxial Schottky diodes for terahertz applications. We present calculations of the (I-V) characteristics of such diodes using a numerical model that considers tunneling. We also present noise and conversion loss predictions of diode mixers operated at 500 GHz, and obtained from a multi-port mixer analysis, using the I-V characteristics predicted by our model. Our calculations indicate that InGaAs/InP heteroepitaxial Schottky barrier diodes are expected to have an I-V characteristic with an ideality factor comparable to that of GaAs Schottky diodes. However, the reverse saturation current of InGaAs/InP diodes is expected to be much greater than that of GaAs diodes. These predictions are confirmed by experiment. The mixer analyses predict that sub-harmonically pumped anti-parallel InGaAs/InP diode mixers are expected to offer a 2 dB greater conversion loss and a somewhat higher single sideband noise temperature than their GaAs counterparts. More importantly, the InGaAs/InP devices are predicted to require only one-tenth of the local oscillator power required by similar GaAs diodes.

System Description for Tank 241-AZ-101 Waste Retrieval Data Acquisition System

DOE Office of Scientific and Technical Information (OSTI.GOV)

ROMERO, S.G.

2000-02-14

The proposed activity provides the description of the Data Acquisition System for Tank 241-AZ-101. This description is documented in HNF-5572, Tank 241-AZ-101 Waste Retrieval Data Acquisition System (DAS). This activity supports the planned mixer pump tests for Tank 241-AZ-101. Tank 241-AZ-101 has been selected for the first full-scale demonstration of a mixer pump system. The tank currently holds over 960,000 gallons of neutralized current acid waste, including approximately 12.7 inches of settling solids (sludge) at the bottom of the tank. As described in Addendum 4 of the FSAR (LMHC 2000a), two 300 HP mixer pumps with associated measurement and monitoringmore » equipment have been installed in Tank 241-AZ-101. The purpose of the Tank 241-AZ-101 retrieval system Data Acquisition System (DAS) is to provide monitoring and data acquisition of key parameters in order to confirm the effectiveness of the mixer pumps utilized for suspending solids in the tank. The suspension of solids in Tank 241-AZ-101 is necessary for pretreatment of the neutralized current acid waste and eventual disposal as glass via the Hanford Waste Vitrification Plant. HNF-5572 provides a basic description of the Tank 241-AZ-101 retrieval system DAS, including the field instrumentation and application software. The DAS is provided to fulfill requirements for data collection and monitoring. This document is not an operations procedure or is it intended to describe the mixing operation. This USQ screening provides evaluation of HNF-5572 (Revision 1) including the changes as documented on ECN 654001. The changes include (1) add information on historical trending and data backup, (2) modify DAS I/O list in Appendix E to reflect actual conditions in the field, and (3) delete IP address in Appendix F per Lockheed Martin Services, Inc. request.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bamberger, Judith A.; Enderlin, Carl W.

Million-gallon double-shell tanks at Hanford are used to store transuranic, high-level, and low-level radioactive wastes. These wastes consist of a large volume of salt-laden solution covering a smaller volume of settled sludge primarily containing metal hydroxides. These wastes will be retrieved and processed into immobile waste forms suitable for permanent disposal. Retrieval is an important step in implementing these disposal scenarios. The retrieval concept evaluated is to use submerged dual-nozzle jet mixer pumps with horizontally oriented nozzles located near the tank floor that produce horizontal jets of fluid to mobilize the settled solids. The mixer pumps are oscillated through 180more » about a vertical axis so the high velocity fluid jets sweep across the floor of the tank. After the solids are mobilized, the pumps will continue to operate at a reduced flow rate producing lower velocity jets sufficient to maintain the particles in a uniform suspension (concentration uniformity). Several types of waste and tank configurations exist at Hanford. The jet mixer pump systems and operating conditions required to mobilize sludge and maintain slurry uniformity will be a function of the waste type and tank configuration. The focus of this work was to conduct a 1/12-scale experiment to develop an analytical model to relate slurry uniformity to tank and mixer pump configurations, operating conditions, and sludge properties. This experimental study evaluated concentration uniformity in a 1/12-scale experiment varying the Reynolds number (Re), Froude number (Fr), and gravitational settling parameter (Gs) space. Simulant physical properties were chosen to obtain the required Re and Gs where Re and Gs were varied by adjusting the kinematic viscosity and mean particle diameter, respectively. Test conditions were achieved by scaling the jet nozzle exit velocity in a 75-in. diameter tank using a mock-up of a centrally located dual-opposed jet mixer pump located just above the tank floor. Concentration measurements at sampling locations throughout the tank were used to assess the degree of uniformity achieved during each test. Concentration data was obtained using a real time in-situ ultrasonic attenuation probe and post-test analysis of discrete batch samples. The undissolved solids concentration at these locations was analyzed to determine whether the tank contents were uniform (≤ ±10% variation about mean) or nonuniform (> ±10% variation about mean) in concentration. Concentration inhomogeneity was modeled as a function of dimensionless parameters. The parameters that best describe the maximum solids volume fraction that can be suspended were found to be 1) the Fr based on nozzle average discharge velocity and tank contents level and 2) the dimensionless particle size based on nozzle diameter. The dependence on the jet Re does not appear to be statistically significant.« less

Potential for Waste Stratification from Back-Dilution in Tank 241-SY-101

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antoniak, Z.I.; Meyer, P.A.

Since late 1997, the floating crust layer in Hanford Tank 241-SY-101 (SY-101) has grown about two meters by gas accumulation. To reverse crust growth and reduce its retained gas volume, the waste in SY-101 will be diluted by transferring at least 300,000 gal of waste out of the tank and replacing it with water. In the fall of 1999, approximately 100,000 gal of this waste will be transferred into Tank SY-102; within a few days of that initial transfer, approximately 100,000 gal of water will be added to SY-101. This initial back-dilution is being planned to ensure that the basemore » of the floating crust layer will be lifted away from the mixer pump inlet with minimal effect on the crust itself. The concern is that the added water will pool under the crust, so the resulting fluid mixture will be too light to lift the crust away from the mixer pump and dissolution at the crust base could cause unwanted gas release. To ensure sufficient mixing to prevent such stratification, water will be added near the tank bottom either through an existing sparge ring on the base of the mixer pump or through the dilution line at the inlet of the transfer pump. A number of simulations using the TEMPEST code showed that the mixing of the water and waste by this method is rapid, and the water does not pool under the crust. Although a density gradient is present, its magnitude is small compared with the difference between the slurry and water density. The result is essentially the same whether water is introduced at the base of the mixer pump or at the transfer pump. There is little effect of water flowrate up to the 500 gpm studied. In all cases, the minimum density remained above that required to float the crust and well above the density of saturated liquid. This indicates that the base of the crust will rise during back-dilution and there will be little or no dissolution of the crust base because the water will be close to saturation from the dissolution of solids in the mixed slurry.« less

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1998-03-31

An apparatus is disclosed for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material. The apparatus consists of a tower bioreactor which has mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1999-03-30

An apparatus is described for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Shot-noise in resistive-diode mixers and the attenuator noise model

NASA Technical Reports Server (NTRS)

Kerr, A. R.

1979-01-01

The representation of a pumped exponential diode, operating as a mixer, by an equivalent lossy network, is reexamined. It is shown that the model is correct provided the network has ports for all sideband frequencies at which (real) power flow can occur between the diode and its embedding. The temperature of the equivalent network is eta/2 times the physical temperature of the diode. The model is valid only if the series resistance and nonlinear capacitance of the diode are negligible. Expressions are derived for the input and output noise temperature and the noise-temperature ratio of ideal mixers. Some common beliefs concerning noise-figure and noise-temperature ratio are shown to be incorrect.

Field study comparing the effect of hydraulic mixing on septic tank performance and sludge accumulation.

PubMed

Almomani, Fares

2016-01-01

This study investigates the effect of hydraulic mixing on anaerobic digestion and sludge accumulation in a septic tank. The performance of a septic tank equipped with a hydraulic mixer was compared with that of a similar standard septic tank over a period of 10 months. The study was conducted in two phases: Phase-I--from May to November 2013 (6 months); Phase-II--from January to May 2014 (4 months). Hydraulic mixing effectively reduced the effluent biological oxygen demand (BOD) and total suspended solids, and reduced the sludge accumulation rate in the septic tank. The BOD removal efficiencies during Phase-II were 65% and 75% in the standard septic tank and a septic tank equipped with hydraulic mixer (Smart Digester™), respectively. The effect of hydraulic mixing reduced the rate of sludge accumulation from 0.64 cm/day to 0.27 cm/day, and increased the pump-out interval by a factor of 3.

Ultrasonic interface level analyzer shop test procedure

DOE Office of Scientific and Technical Information (OSTI.GOV)

STAEHR, T.W.

1999-05-24

The Royce Instrument Corporation Model 2511 Interface Level Analyzer (URSILLA) system uses an ultrasonic ranging technique (SONAR) to measure sludge depths in holding tanks. Three URSILLA instrument assemblies provided by the W-151 project are planned to be used during mixer pump testing to provide data for determining sludge mobilization effectiveness of the mixer pumps and sludge settling rates. The purpose of this test is to provide a documented means of verifying that the functional components of the three URSILLA instruments operate properly. Successful completion of this Shop Test Procedure (STP) is a prerequisite for installation in the AZ-101 tank. Themore » objective of the test is to verify the operation of the URSILLA instruments and to verify data collection using a stand alone software program.« less

Apparatus and method for gelling liquefied gasses

NASA Technical Reports Server (NTRS)

Elliott, Adam (Inventor); DiSalvo, Roberto (Inventor); Shepherd, Phillip (Inventor); Kosier, Ryan (Inventor)

2010-01-01

The present invention is a method and apparatus for gelling liquid propane and other liquefied gasses. The apparatus includes a temperature controlled churn mixer, vacuum pump, liquefied gas transfer tank, and means for measuring amount of material entering the mixer. The method uses gelling agents such as silicon dioxide, clay, carbon, or organic or inorganic polymers, as well as dopants such as titanium, aluminum, and boron powders. The apparatus and method are particularly useful for the production of high quality rocket fuels and propellants.

Large dynamic range terahertz spectrometers based on plasmonic photomixers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Wang, Ning; Javadi, Hamid; Jarrahi, Mona

2017-02-01

Heterodyne terahertz spectrometers are highly in demand for space explorations and astrophysics studies. A conventional heterodyne terahertz spectrometer consists of a terahertz mixer that mixes a received terahertz signal with a local oscillator signal to generate an intermediate frequency signal in the radio frequency (RF) range, where it can be easily processed and detected by RF electronics. Schottky diode mixers, superconductor-insulator-superconductor (SIS) mixers and hot electron bolometer (HEB) mixers are the most commonly used mixers in conventional heterodyne terahertz spectrometers. While conventional heterodyne terahertz spectrometers offer high spectral resolution and high detection sensitivity levels at cryogenic temperatures, their dynamic range and bandwidth are limited by the low radiation power of existing terahertz local oscillators and narrow bandwidth of existing terahertz mixers. To address these limitations, we present a novel approach for heterodyne terahertz spectrometry based on plasmonic photomixing. The presented design replaces terahertz mixer and local oscillator of conventional heterodyne terahertz spectrometers with a plasmonic photomixer pumped by an optical local oscillator. The optical local oscillator consists of two wavelength-tunable continuous-wave optical sources with a terahertz frequency difference. As a result, the spectrometry bandwidth and dynamic range of the presented heterodyne spectrometer is not limited by radiation frequency and power restrictions of conventional terahertz sources. We demonstrate a proof-of-concept terahertz spectrometer with more than 90 dB dynamic range and 1 THz spectrometry bandwidth.

Energy Efficient Engine Exhaust Mixer Model Technology

NASA Technical Reports Server (NTRS)

Kozlowski, H.; Larkin, M.

1981-01-01

An exhaust mixer test program was conducted to define the technology required for the Energy Efficient Engine Program. The model configurations of 1/10 scale were tested in two phases. A parametric study of mixer design options, the impact of residual low pressure turbine swirl, and integration of the mixer with the structural pylon of the nacelle were investigated. The improvement of the mixer itself was also studied. Nozzle performance characteristics were obtained along with exit profiles and oil smear photographs. The sensitivity of nozzle performance to tailpipe length, lobe number, mixer penetration, and mixer modifications like scalloping and cutbacks were established. Residual turbine swirl was found detrimental to exhaust system performance and the low pressure turbine system for Energy Efficient Engine was designed so that no swirl would enter the mixer. The impact of mixer/plug gap was also established, along with importance of scalloping, cutbacks, hoods, and plug angles on high penetration mixers.

Spectral linewidth preservation in parametric frequency combs seeded by dual pumps.

PubMed

Tong, Zhi; Wiberg, Andreas O J; Myslivets, Evgeny; Kuo, Bill P P; Alic, Nikola; Radic, Stojan

2012-07-30

We demonstrate new technique for generation of programmable-pitch, wideband frequency combs with low phase noise. The comb generation was achieved using cavity-less, multistage mixer driven by two tunable continuous-wave pump seeds. The approach relies on phase-correlated continuous-wave pumps in order to cancel spectral linewidth broadening inherent to parametric comb generation. Parametric combs with over 200-nm bandwidth were obtained and characterized with respect to phase noise scaling to demonstrate linewidth preservation over 100 generated tones.

Effect of Installation of Mixer/Ejector Nozzles on the Core Flow Exhaust of High-Bypass-Ratio Turbofan Engines

NASA Technical Reports Server (NTRS)

Harrington, Douglas E.

1998-01-01

The aerospace industry is currently investigating the effect of installing mixer/ejector nozzles on the core flow exhaust of high-bypass-ratio turbofan engines. This effort includes both full-scale engine tests at sea level conditions and subscale tests in static test facilities. Subscale model tests are to be conducted prior to full-scale testing. With this approach, model results can be analyzed and compared with analytical predications. Problem areas can then be identified and design changes made and verified in subscale prior to committing to any final design configurations for engine ground tests. One of the subscale model test programs for the integrated mixer/ejector development was a joint test conducted by the NASA Lewis Research Center and Pratt & Whitney Aircraft. This test was conducted to study various mixer/ejector nozzle configurations installed on the core flow exhaust of advanced, high-bypass-ratio turbofan engines for subsonic, commercial applications. The mixer/ejector concept involves the introduction of largescale, low-loss, streamwise vortices that entrain large amounts of secondary air and rapidly mix it with the primary stream. This results in increased ejector pumping relative to conventional ejectors and in more complete mixing within the ejector shroud. The latter improves thrust performance through the efficient energy exchange between the primary and secondary streams. This experimental program was completed in April 1997 in Lewis' CE-22 static test facility. Variables tested included the nozzle area ratio (A9/A8), which ranged from 1.6 to 3.0. This ratio was varied by increasing or decreasing the nozzle throat area, A8. Primary nozzles tested included both lobed mixers and conical primaries. These configurations were tested with and without an outer shroud, and the shroud position was varied by inserting spacers in it. In addition, data were acquired with and without secondary flow.

Design of a Small-Scale Multi-Inlet Vortex Mixer for Scalable Nanoparticle Production and Application to the Encapsulation of Biologics by Inverse Flash NanoPrecipitation.

PubMed

Markwalter, Chester E; Prud'homme, Robert K

2018-05-14

Flash NanoPrecipitation (FNP) is a scalable approach to generate polymeric nanoparticles using rapid micromixing in specially-designed geometries such as a confined impinging jets (CIJ) mixer or a Multi-Inlet Vortex Mixer (MIVM). A major limitation of formulation screening using the MIVM is that a single run requires tens of milligrams of the therapeutic. To overcome this, we have developed a scaled-down version of the MIVM, requiring as little as 0.2 mg of therapeutic, for formulation screening. The redesigned mixer can then be attached to pumps for scale-up of the identified formulation. It was shown that Reynolds Number allowed accurate scaling between the two MIVM designs. The utility of the small-scale MIVM for formulation development was demonstrated through the encapsulation of a number of hydrophilic macromolecules using inverse Flash NanoPrecipitation with target loadings as high as 50% by mass. Copyright © 2018. Published by Elsevier Inc.

Transient thermal analysis for radioactive liquid mixing operations in a large-scaled tank

DOE PAGES

Lee, S. Y.; Smith, III, F. G.

2014-07-25

A transient heat balance model was developed to assess the impact of a Submersible Mixer Pump (SMP) on radioactive liquid temperature during the process of waste mixing and removal for the high-level radioactive materials stored in Savannah River Site (SRS) tanks. The model results will be mainly used to determine the SMP design impacts on the waste tank temperature during operations and to develop a specification for a new SMP design to replace existing longshaft mixer pumps used during waste removal. The present model was benchmarked against the test data obtained by the tank measurement to examine the quantitative thermalmore » response of the tank and to establish the reference conditions of the operating variables under no SMP operation. The results showed that the model predictions agreed with the test data of the waste temperatures within about 10%.« less

Centaur Propellant Thermal Conditioning Study

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Pleasant, R. L.; Erickson, R. C.

1976-01-01

A wicking investigation revealed that passive thermal conditioning was feasible and provided considerable weight advantage over active systems using throttled vent fluid in a Centaur D-1s launch vehicle. Experimental wicking correlations were obtained using empirical revisions to the analytical flow model. Thermal subcoolers were evaluated parametrically as a function of tank pressure and NPSP. Results showed that the RL10 category I engine was the best candidate for boost pump replacement and the option showing the lowest weight penalty employed passively cooled acquisition devices, thermal subcoolers, dry ducts between burns and pumping of subcooler coolant back into the tank. A mixing correlation was identified for sizing the thermodynamic vent system mixer. Worst case mixing requirements were determined by surveying Centaur D-1T, D-1S, IUS, and space tug vehicles. Vent system sizing was based upon worst case requirements. Thermodynamic vent system/mixer weights were determined for each vehicle.

Scale model performance test investigation of mixed flow exhaust systems for an energy efficient engine /E3/ propulsion system

NASA Technical Reports Server (NTRS)

Kuchar, A. P.; Chamberlin, R.

1983-01-01

As part of the NASA Energy Efficient Engine program, scale-model performance tests of a mixed flow exhaust system were conducted. The tests were used to evaluate the performance of exhaust system mixers for high-bypass, mixed-flow turbofan engines. The tests indicated that: (1) mixer penetration has the most significant affect on both mixing effectiveness and mixer pressure loss; (2) mixing/tailpipe length improves mixing effectiveness; (3) gap reduction between the mixer and centerbody increases high mixing effectiveness; (4) mixer cross-sectional shape influences mixing effectiveness; (5) lobe number affects mixing degree; and (6) mixer aerodynamic pressure losses are a function of secondary flows inherent to the lobed mixer concept.

Performance evaluation of rotating pump jet mixing of radioactive wastes in Hanford Tanks 241-AP-102 and -104

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onishi, Y.; Recknagle, K.P.

The purpose of this study was to confirm the adequacy of a single mixer pump to fully mix the wastes that will be stored in Tanks 241-AP-102 and -104. These Hanford double-shell tanks (DSTs) will be used as staging tanks to receive low-activity wastes from other Hanford storage tanks and, in turn, will supply the wastes to private waste vitrification facilities for eventual solidification. The TEMPEST computer code was applied to Tanks AP-102 and -104 to simulate waste mixing generated by the 60-ft/s rotating jets and to determine the effectiveness of the single rotating pump to mix the waste. TEMPESTmore » simulates flow and mass/heat transport and chemical reactions (equilibrium and kinetic reactions) coupled together. Section 2 describes the pump jet mixing conditions the authors evaluated, the modeling cases, and their parameters. Section 3 reports model applications and assessment results. The summary and conclusions are presented in Section 4, and cited references are listed in Section 5.« less

[An object-oriented intelligent engineering design approach for lake pollution control].

PubMed

Zou, Rui; Zhou, Jing; Liu, Yong; Zhu, Xiang; Zhao, Lei; Yang, Ping-Jian; Guo, Huai-Cheng

2013-03-01

Regarding the shortage and deficiency of traditional lake pollution control engineering techniques, a new lake pollution control engineering approach was proposed in this study, based on object-oriented intelligent design (OOID) from the perspective of intelligence. It can provide a new methodology and framework for effectively controlling lake pollution and improving water quality. The differences between the traditional engineering techniques and the OOID approach were compared. The key points for OOID were described as object perspective, cause and effect foundation, set points into surface, and temporal and spatial optimization. The blue algae control in lake was taken as an example in this study. The effect of algae control and water quality improvement were analyzed in details from the perspective of object-oriented intelligent design based on two engineering techniques (vertical hydrodynamic mixer and pumping algaecide recharge). The modeling results showed that the traditional engineering design paradigm cannot provide scientific and effective guidance for engineering design and decision-making regarding lake pollution. Intelligent design approach is based on the object perspective and quantitative causal analysis in this case. This approach identified that the efficiency of mixers was much higher than pumps in achieving the goal of low to moderate water quality improvement. However, when the objective of water quality exceeded a certain value (such as the control objective of peak Chla concentration exceeded 100 microg x L(-1) in this experimental water), the mixer cannot achieve this goal. The pump technique can achieve the goal but with higher cost. The efficiency of combining the two techniques was higher than using one of the two techniques alone. Moreover, the quantitative scale control of the two engineering techniques has a significant impact on the actual project benefits and costs.

Numerical Investigation on Aerodynamic and Combustion Performance of Chevron Mixer Inside an Afterburner.

PubMed

Yong, Shan; JingZhou, Zhang; Yameng, Wang

2014-11-01

To improve the performance of the afterburner for the turbofan engine, an innovative type of mixer, namely, the chevron mixer, was considered to enhance the mixture between the core flow and the bypass flow. Computational fluid dynamics (CFD) simulations investigated the aerodynamic performances and combustion characteristics of the chevron mixer inside a typical afterburner. Three types of mixer, namely, CC (chevrons tilted into core flow), CB (chevrons tilted into bypass flow), and CA (chevrons tilted into core flow and bypass flow alternately), respectively, were studied on the aerodynamic performances of mixing process. The chevrons arrangement has significant effect on the mixing characteristics and the CA mode seems to be advantageous for the generation of the stronger streamwise vortices with lower aerodynamic loss. Further investigations on combustion characteristics for CA mode were performed. Calculation results reveal that the local temperature distribution at the leading edge section of flame holder is improved under the action of streamwise vortices shedding from chevron mixers. Consequently, the combustion efficiency increased by 3.5% compared with confluent mixer under the same fuel supply scheme.

Zero Gravity Cryogenic Vent System Concepts for Upper Stages

NASA Astrophysics Data System (ADS)

Ravex, Alain; Flachbart, Robin; Holt, Barney

The capability to vent in zero gravity without resettling is a technology need that involves practically all uses of sub-critical cryogenics in space. Venting without resettling would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity vent concept, termed a thermodynamic vent system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule-Thomson (J-T) valve to extract thermal energy from the propellant. Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (MHTB) was used to test both spray bar and axial jet TVS concepts. The axial jet system consists of a recirculation pump heat exchanger unit. The spray bar system consists of a recirculation pump, a parallel flow concentric tube, heat exchanger, and a spray bar positioned close to the longitudinal axis of the tank. The operation of both concepts is similar. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it into the tank liquid, ullage, and exposed tank surfaces. When energy extraction is required, a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the heat exchanger, and is vented overboard. The vented vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point, the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating boil-off losses. TVS performance testing demonstrated that the spray bar was effective in providing tank pressure control within a 6.89 kPa (1psi) band for fill levels of 90%, 50%, and 25%. Complete destratification of the liquid and ullage was achieved at these fill levels. The axial jet was effective in providing tank pressure control within the same pressure control band at the 90% fill level. However, at the 50% level, the system reached a point at which it was unable to extract enough energy to keep up with the heat leak into the tank. Due to a hardware problem, the recirculation pump operated well below the axial jet design flow rate. Therefore, it is likely that the performance of the axial jet would have improved had the pump operated at the proper flow rate. A CFD model is being used to determine if the desired axial jet performance would be achieved if a higher pump flow rate were available. Testing conducted thus far has demonstrated that both TVS concepts can be effective in destratifying a propellant tank, rejecting stored heat energy, and thus, controlling tank pressure.

Frequency stabilization of an optically pumped far-infrared laser to the harmonic of a microwave synthesizer.

PubMed

Danylov, A A; Light, A R; Waldman, J; Erickson, N

2015-12-10

Measurements of the frequency stability of a far-infrared molecular laser have been made by mixing the harmonic of an ultrastable microwave source with a portion of the laser output signal in a terahertz (THz) Schottky diode balanced mixer. A 3 GHz difference-frequency signal was used in a frequency discriminator circuit to lock the laser to the microwave source. Comparisons of the short- and long-term laser frequency stability under free-running and locked conditions show a significant improvement with locking. Short-term frequency jitter was reduced by an order of magnitude, from approximately 40 to 4 kHz, and long-term drift was reduced by more than three orders of magnitude, from approximately 250 kHz to 80 Hz. The results, enabled by the efficient Schottky diode balanced mixer downconverter, demonstrate that ultrastable microwave-based frequency stabilization of THz optically pumped lasers (OPLs) will now be possible at frequencies extending well above 4.0 THz.

Assessment of performing an MST strike in Tank 21H

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poirier, Michael R.

2014-09-29

Previous Savannah River National Laboratory (SRNL) tank mixing studies performed for the Small Column Ion Exchange (SCIX) project have shown that 3 Submersible Mixer Pumps (SMPs) installed in Tank 41 are sufficient to support actinide removal by MST sorption as well as subsequent resuspension and removal of settled solids. Savannah River Remediation (SRR) is pursuing MST addition into Tank 21 as part of the Large Tank Strike (LTS) project. The preliminary scope for LTS involves the use of three standard slurry pumps (installed in N, SE, and SW risers) in a Type IV tank. Due to the differences in tankmore » size, internal interferences, and pump design, a separate mixing evaluation is required to determine if the proposed configuration will allow for MST suspension and strontium and actinide sorption. The author performed the analysis by reviewing drawings for Tank 21 [W231023] and determining the required cleaning radius or zone of influence for the pumps. This requirement was compared with previous pilot-scale MST suspension data collected for SCIX that determined the cleaning radius, or zone of influence, as a function of pump operating parameters. The author also reviewed a previous Tank 50 mixing analysis that examined the ability of standard slurry pumps to suspend sludge particles. Based on a review of the pilot-scale SCIX mixing tests and Tank 50 pump operating experience, three standard slurry pumps should be able to suspend sludge and MST to effectively sorb strontium and actinides onto the MST. Using the SCIX data requires an assumption about the impact of cooling coils on slurry pump mixing. The basis for this assumption is described in this report. Using the Tank 50 operating experience shows three standard slurry pumps should be able to suspend solids if the shear strength of the settled solids is less than 160 Pa. Because Tank 21 does not contain cooling coils, the shear strength could be larger.« less

Testing the Effects of Helium Pressurant on Thermodynamic Vent System Performance with Liquid Hydrogen

NASA Technical Reports Server (NTRS)

Flachbart, R. H.; Hastings, L. J.; Hedayat, A.; Nelson, S.; Tucker, S.

2006-01-01

In support of the development of a zero gravity pressure control capability for liquid hydrogen, testing was conducted at the Marshall Space Flight Center using the Multipurpose Hydrogen Test Bed (MHTB) to evaluate the effects of helium pressurant on the performance of a spray bar thermodynamic vent system (TVS). Fourteen days of testing was performed in August - September 2005, with an ambient heat leak of about 70-80 watts and tank fill levels of 90%, 50%, and 25%. The TVS successfully controlled the tank pressure within a +/- 3.45 kPa (+/- 0.5 psi) band with various helium concentration levels in the ullage. Relative to pressure control with an "all hydrogen" ullage, the helium presence resulted in 10 to 30 per cent longer pressure reduction durations, depending on the fill level, during the mixing/venting phase of the control cycle. Additionally, the automated control cycle was based on mixing alone for pressure reduction until the pressure versus time slope became positive, at which time the Joule-Thomson vent was opened. Testing was also conducted to evaluate thermodynamic venting without the mixer operating, first with liquid then with vapor at the recirculation line inlet. Although ullage stratification was present, the ullage pressure was successfully controlled without the mixer operating. Thus, if vapor surrounded the pump inlet in a reduced gravity situation, the ullage pressure can still be controlled by venting through the TVS Joule Thomson valve and heat exchanger. It was evident that the spray bar configuration, which extends almost the entire length of the tank, enabled significant thermal energy removal from the ullage even without the mixer operating. Details regarding the test setup and procedures are presented in the paper. 1

Performance of all-NbN superconductive tunnel junctions as mixers at 205 GHz

NASA Technical Reports Server (NTRS)

Mcgrath, W. R.; Leduc, H. G.; Stern, J. A.

1990-01-01

Small-area (1x1 sq micron) high-current-density NbN-MgO-NbN tunnel junctions with I-V characteristics suitable for high frequency mixers were fabricated. These junctions are integrated with superconducting microstrip lines designed to resonate out the large junction capacitance. The mixer gain and noise performance were studied near 205 GHz as a function of the inductance provided by the microstrip. This has yielded values of junction capacitance of 85 fF/sq microns and magnetic penetration depth of 3800 angstroms. Mixer noise as low as 133 K has been obtained for properly tuned junctions. This is the best noise performance ever reported for an NbN SIS mixer.

Experimental evaluation of exhaust mixers for an Energy Efficient Engine

NASA Technical Reports Server (NTRS)

Kozlowski, H.; Kraft, G.

1980-01-01

Static scale model tests were conducted to evaluate exhaust system mixers for a high bypass ratio engine as part of the NASA sponsored Energy Efficient program. Gross thrust coefficients were measured for a series of mixer configurations which included variations in the number of mixer lobes, tailpipe length, mixer penetration, and length. All of these parameters have a significant impact on exhaust system performance. In addition, flow visualization pictures and pressure/temperature traverses were obtained for selected configurations. Parametric performance trends are discussed and the results considered relative to the Energy Efficient Engine program goals.

Scale model performance test investigation of exhaust system mixers for an Energy Efficient Engine /E3/ propulsion system

NASA Technical Reports Server (NTRS)

Kuchar, A. P.; Chamberlin, R.

1980-01-01

A scale model performance test was conducted as part of the NASA Energy Efficient Engine (E3) Program, to investigate the geometric variables that influence the aerodynamic design of exhaust system mixers for high-bypass, mixed-flow engines. Mixer configuration variables included lobe number, penetration and perimeter, as well as several cutback mixer geometries. Mixing effectiveness and mixer pressure loss were determined using measured thrust and nozzle exit total pressure and temperature surveys. Results provide a data base to aid the analysis and design development of the E3 mixed-flow exhaust system.

Processing Impact on Monoclonal Antibody Drug Products: Protein Subvisible Particulate Formation Induced by Grinding Stress.

PubMed

Gikanga, Benson; Eisner, Devon Roshan; Ovadia, Robert; Day, Eric S; Stauch, Oliver B; Maa, Yuh-Fun

2017-01-01

Subvisible particle formation in monoclonal antibody drug product resulting from mixing and filling operations represents a significant processing risk that can lead to filter fouling and thereby lead to process delays or failures. Several previous studies from our lab and others demonstrated the formation of subvisible particulates in mAb formulations resulting from mixing operations using some bottom-mounted mixers or stirrer bars. It was hypothesized that the stress (e.g., shear/cavitation) derived from tight clearance and/or close contact between the impeller and shaft was responsible for protein subvisible particulate generation. These studies, however, could not distinguish between the two surfaces without contact (tight clearance) or between two contacting surfaces (close contact). In the present study we expand on those findings and utilize small-scale mixing models that are able to, for the first time, distinguish between tight clearances and tight contact. In this study we evaluated different mixer types including a top-mounted mixer, several impeller-based bottom-mounted mixers, and a rotary piston pump. The impact of tight clearance/close contact on subvisible particle formation in at-scale mixing platforms was demonstrated in the gap between the impeller and drive unit as well as between the piston and the housing of the pump. Furthermore, small-scale mixing models based on different designs of magnetic stir bars that mimic the tight clearance/close contact of the manufacturing-scale mixers also induced subvisible particles in mAb formulations. Additional small-scale models that feature tight clearance but no close contact (grinding) suggested that it is the repeated grinding/contacting of the moving parts and not the presence of tight clearance in the processing equipment that is the root cause of protein subvisible particulate formation. When multiple mAbs, Fabs (fragment antigen binding), or non-antibody related proteins were mixed in the small-scale mixing model, for molecules investigated, it was observed that mAbs and Fabs appear to be more susceptible to particle formation than non-antibody-related proteins. In the grinding zone, mAb/Fab molecules aggregated into insoluble particles with neither detectable soluble aggregates nor fragmented species. This investigation represents a step closer to the understanding of the underlying stress mechanism leading to mAb subvisible particulate formation as the result of drug product processing. LAY ABSTRACT: Mixing and fill finish are important unit operations in drug product manufacturing for compounding (dilution, pooling, homogenization, etc.) and filling into primary packaging containers (vials, pre-filled syringes, etc.), respectively. The current trend in adopting bottom-mounted mixers as well as low fill-volume filling systems has raised concerns about their impact on drug product quality and process performance. However, investigations into the effects of their use for biopharmaceutical products, particularly monoclonal antibody formulations, are rarely published. The purpose of this study is three-fold: (1) to revisit the impact of bottom-mounted mixer design on monoclonal antibody subvisible particle formation; (2) to identify the root cause for subvisible particle formation; and (3) to fully utilize available particle analysis tools to demonstrate the correlation between particle count in the solution and filter fouling during sterile filtration. The outcomes of this study will benefit scientists and engineers who develop biologic product manufacturing processes by providing a better understanding of drug product process challenges. © PDA, Inc. 2017.

Metallurgical technologies, energy conversion, and magnetohydrodynamic flows

NASA Astrophysics Data System (ADS)

Branover, Herman; Unger, Yeshajahu

The present volume discusses metallurgical applications of MHD, R&D on MHD devices employing liquid working medium for process applications, electromagnetic (EM) modulation of molten metal flow, EM pump performance of superconducting MHD devices, induction EM alkali-metal pumps, a physical model for EM-driven flow in channel-induction furnaces, grain refinement in Al alloys via EM vibrational method, dendrite growth of solidifying metal in dc magnetic field, MHD for mass and heat transfer in single-crystal melt growth, inverse EM shaping, and liquid-metal MHD development in Israel. Also discussed are the embrittlement of steel by lead, an open cycle MHD disk generator, the acceleration of gas-liquid piston flows for molten-metal MHD generators, MHD flow around a cylinder, new MHD drag coefficients, liquid-metal MHD two-phase flow, and two-phase liquid gas mixers for MHD energy conversion. (No individual items are abstracted in this volume)

Fully Integrated Microfluidic Device for Direct Sample-to-Answer Genetic Analysis

NASA Astrophysics Data System (ADS)

Liu, Robin H.; Grodzinski, Piotr

Integration of microfluidics technology with DNA microarrays enables building complete sample-to-answer systems that are useful in many applications such as clinic diagnostics. In this chapter, a fully integrated microfluidic device [1] that consists of microfluidic mixers, valves, pumps, channels, chambers, heaters, and a DNA microarray sensor to perform DNA analysis of complex biological sample solutions is present. This device can perform on-chip sample preparation (including magnetic bead-based cell capture, cell preconcentration and purification, and cell lysis) of complex biological sample solutions (such as whole blood), polymerase chain reaction, DNA hybridization, and electrochemical detection. A few novel microfluidic techniques were developed and employed. A micromix-ing technique based on a cavitation microstreaming principle was implemented to enhance target cell capture from whole blood samples using immunomagnetic beads. This technique was also employed to accelerate DNA hybridization reaction. Thermally actuated paraffin-based microvalves were developed to regulate flows. Electrochemical pumps and thermopneumatic pumps were integrated on the chip to provide pumping of liquid solutions. The device is completely self-contained: no external pressure sources, fluid storage, mechanical pumps, or valves are necessary for fluid manipulation, thus eliminating possible sample contamination and simplifying device operation. Pathogenic bacteria detection from ~mL whole blood samples and single-nucleotide polymorphism analysis directly from diluted blood were demonstrated. The device provides a cost-effective solution to direct sample-to-answer genetic analysis, and thus has a potential impact in the fields of point-of-care genetic analysis, environmental testing, and biological warfare agent detection.

Planar doped barrier subharmonic mixers

NASA Technical Reports Server (NTRS)

Lee, T. H.; East, J. R.; Haddad, G. I.

1992-01-01

The Planar Doped Barrier (PDB) diode is a device consisting of a p(+) doping spike between two intrinsic layers and n(+) ohmic contacts. This device has the advantages of controllable barrier height, diode capacitance and forward to reverse current ratio. A symmetrically designed PDB has an anti-symmetric current vs. voltage characteristic and is ideal for use as millimeter wave subharmonic mixers. We have fabricated such devices with barrier heights of 0.3, 0.5 and 0.7 volts from GaAs and InGaAs using a multijunction honeycomb structure with junction diameters between one and ten microns. Initial RF measurements are encouraging. The 0.7 volt barrier height 4 micron GaAs devices were tested as subharmonic mixers at 202 GHz with an IF frequency of 1 GHz and had 18 dB of conversion loss. The estimated mismatch loss was 7 dB and was due to higher diode capacitance. The LO frequency was 100.5 GHz and the pump power was 8 mW.

Tank 241-AZ-101 criticality assessment resulting from pump jet mixing: Sludge mixing simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onishi, Y.; Recknagle, K.

Tank 241-AZ-101 (AZ-101) is one of 28 double-shell tanks located in the AZ farm in the Hanford Site`s 200 East Area. The tank contains a significant quantity of fissile materials, including an estimated 9.782 kg of plutonium. Before beginning jet pump mixing for mitigative purposes, the operations must be evaluated to demonstrate that they will be subcritical under both normal and credible abnormal conditions. The main objective of this study was to address a concern about whether two 300-hp pumps with four rotating 18.3-m/s (60-ft/s) jets can concentrate plutonium in their pump housings during mixer pump operation and cause amore » criticality. The three-dimensional simulation was performed with the time-varying TEMPEST code to determine how much the pump jet mixing of Tank AZ-101 will concentrate plutonium in the pump housing. The AZ-101 model predicted that the total amount of plutonium within the pump housing peaks at 75 g at 10 simulation seconds and decreases to less than 10 g at four minutes. The plutonium concentration in the entire pump housing peaks at 0.60 g/L at 10 simulation seconds and is reduced to below 0.1 g/L after four minutes. Since the minimum critical concentration of plutonium is 2.6 g/L, and the minimum critical plutonium mass under idealized plutonium-water conditions is 520 g, these predicted maximums in the pump housing are much lower than the minimum plutonium conditions needed to reach a criticality level. The initial plutonium maximum of 1.88 g/L still results in safety factor of 4.3 in the pump housing during the pump jet mixing operation.« less

Planar doped barrier devices for subharmonic mixers

NASA Technical Reports Server (NTRS)

Lee, T. H.; East, J. R.; Haddad, G. I.

1991-01-01

An overview is given of planar doped barrier (PDB) devices for subharmonic mixer applications. A simplified description is given of PDB characteristics along with a more complete numerical analysis of the current versus voltage characteristics of typical structures. The analysis points out the tradeoffs between the device structure and the resulting characteristics that are important for mixer performance. Preliminary low-frequency characterization results are given for the device structures, and a computer analysis of subharmonic mixer parameters and performance is presented.

Zero Gravity Cryogenic Vent System Concepts for Upper Stages

NASA Technical Reports Server (NTRS)

Flachbart, Robin H.; Holt, James B.; Hastings, Leon J.

1999-01-01

The capability to vent in zero gravity without resettling is a technology need that involves practically all uses of sub-critical cryogenics in space. Venting without resettling would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity vent concept, termed a thermodynamic vent system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule-Thomson (J-T) valve to extract thermal energy from the propellant. Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (MHTB) was used to test both spray bar and axial jet TVS concepts. The axial jet system consists of a recirculation pump heat exchanger unit. The spray bar system consists of a recirculation pump, a parallel flow concentric tube, heat exchanger, and a spray bar positioned close to the longitudinal axis of the tank. The operation of both concepts is similar. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it into the tank liquid, ullage, and exposed tank surfaces. When energy is required. a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the heat exchanger, and is vented overboard. The vented vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point. the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating, boil-off losses.

Zero Gravity Cryogenic Vent System Concepts for Upper Stages

NASA Technical Reports Server (NTRS)

Flachbart, Robin H.; Holt, James B.; Hastings, Leon J.

2001-01-01

The capability to vent in zero gravity without resettling is a technology need that involves practically all uses of sub-critical cryogenics in space, and would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity vent concept, termed a thermodynamic vent system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule-Thomson (J-T) valve to extract thermal energy from the propellant. Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (MHTB) was used to test both spray-bar and axial jet TVS concepts. The axial jet system consists of a recirculation pump heat exchanger unit. The spray-bar system consists of a recirculation pump, a parallel flow concentric tube heat exchanger, and a spray-bar positioned close to the longitudinal axis of the tank. The operation of both concepts is similar. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it into the tank liquid, ullage, and exposed tank surfaces. When energy extraction is required, a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the heat exchanger, and is vented overboard. The vented vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point, the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating boil-off losses.

Novel index for micromixing characterization and comparative analysis

PubMed Central

Jain, Mranal; Nandakumar, K.

2010-01-01

The most basic micromixer is a T- or Y-mixer, where two confluent streams mix due to transverse diffusion. To enhance micromixing, various modifications of T-mixers are reported such as heterogeneously charged walls, grooves on the channel base, geometric variations by introducing physical constrictions, etc. The performance of these reported designs is evaluated against the T-mixer in terms of the deviation from perfectly mixed state and mixing length (device length required to achieve perfect mixing). Although many studies have noticed the reduced flow rates for improved mixer designs, the residence time is not taken into consideration for micromixing performance evaluation. In this work, we propose a novel index, based on residence time, for micromixing characterization and comparative analysis. For any given mixer, the proposed index identifies the nondiffusive mixing enhancement with respect to the T-mixer. Various micromixers are evaluated using the proposed index to demonstrate the usefulness of the index. It is also shown that physical constriction mixer types are equivalent to T-mixers. The proposed index is found to be insightful and could be used as a benchmark for comparing different mixing strategies. PMID:20689773

Continuous inline blending of antimisting kerosene

NASA Technical Reports Server (NTRS)

Parikh, P.; Yavrouian, A.; Sarohia, V.

1985-01-01

A continuous inline blender was developed to blend polymer slurries with a stream of jet A fuel. The viscosity of the slurries ranged widely. The key element of the blender was a static mixer placed immediately downstream of the slurry injection point. A positive displacement gear pump for jet A was employed, and a progressive cavity rotary screw pump was used for slurry pumping. Turbine flow meters were employed for jet A metering while the slurry flow rate was calibrated against the pressure drop in the injection tube. While using one of the FM-9 variant slurries, a provision was made for a time delay between the addition of slurry and the addition of amine sequentially into the jet A stream.

AC electrothermal mixing for high conductive biofluids by arc-electrodes

NASA Astrophysics Data System (ADS)

Meng, Jiyu; Li, Shanshan; Li, Junwei; Yu, Chengzhuang; Wei, Chunyang; Dai, Shijie

2018-06-01

As a platform to mix the bioagents (i.e. serum, urine), we take advantage of the alternating current electrothermal (ACET) effect which is quite suitable for rapid pumping/mixing of high conductive biomicrofluids. Here we demonstrate the concept of a high-efficient mixing microfluidic chip as a basic unit to provide rapid mixing for lab-on-a-chip applications. As an active mixer, two streams are introduced into a ring-shape microchamber by a passive flow rate regulator, and then the microfluids in the chamber are actuated by a nonuniform electric field with a phase shift of 180°. It shows perfect mixing performance by arranging four arc-electrodes around the ring-shape microchamber subsequently. Taking the Joule heating and conductivity/permittivity changes into consideration, a temperature dependent fully coupled numerical model is presented. Then, the effects of applied voltages on mixing performance and temperature rise are provided to get an optimized design for ACET mixer. Moreover, the arrangement of the electrode array is analyzed to show the effects of electrode patterns on the swirls and mixing efficiencies. Since all the electrodes here are located along a ring-shape central microchamber, the ring-shape micromixer is quite suitable to function as a compact element modular for integrated microfluidic chips.

A Dual Polarized Quasi-Optical SIS Mixer at 550-GHz

NASA Technical Reports Server (NTRS)

Chattopadhyay, Goutam; Miller, David; LeDuc, Henry G.; Zmuidzinas, Jonas

2000-01-01

We describe the design, fabrication, and the performance of a low-noise dual-polarized quasi-optical superconductor insulator superconductor (SIS) mixer at 550 GHz. The mixer utilizes a novel cross-slot antenna on a hyperhemispherical substrate lens, two junction tuning circuits, niobium trilayer junctions, and an IF circuit containing a lumped element 180 deg hybrid. The antenna consists of an orthogonal pair of twin-slot antennas, and has four feed points, two for each polarization. Each feed point is coupled to a two-junction SIS mixer. The 180 deg IF hybrid is implemented using a lumped element/microstrip circuit located inside the mixer block. Fourier transform spectrometer (FTS) measurements of the mixer frequency response show good agreement with computer simulations. The measured co-polarized and cross-polarized patterns for both polarizations also agree with the theoretical predictions. The noise performance of the dual-polarized mixer is excellent, giving uncorrected receiver noise temperature of better than 115 K (DSB) at 528 GHz for both the polarizations.

Improving the Efficiency of 3-D Hydrogeological Mixers: Dilution Enhancement Via Coupled Engineering-Induced Transient Flows and Spatial Heterogeneity

NASA Astrophysics Data System (ADS)

Di Dato, Mariaines; de Barros, Felipe P. J.; Fiori, Aldo; Bellin, Alberto

2018-03-01

Natural attenuation and in situ oxidation are commonly considered as low-cost alternatives to ex situ remediation. The efficiency of such remediation techniques is hindered by difficulties in obtaining good dilution and mixing of the contaminant, in particular if the plume deformation is physically constrained by an array of wells, which serves as a containment system. In that case, dilution may be enhanced by inducing an engineered sequence of injections and extractions from such pumping system, which also works as a hydraulic barrier. This way, the aquifer acts as a natural mixer, in a manner similar to the industrialized engineered mixers. Improving the efficiency of hydrogeological mixers is a challenging task, owing to the need to use a 3-D setup while relieving the computational burden. Analytical solutions, though approximated, are a suitable and efficient tool to seek the optimum solution among all possible flow configurations. Here we develop a novel physically based model to demonstrate how the combined spatiotemporal fluctuations of the water fluxes control solute trajectories and residence time distributions and therefore, the effectiveness of contaminant plume dilution and mixing. Our results show how external forcing configurations are capable of inducing distinct time-varying groundwater flow patterns which will yield different solute dilution rates.

Performance of an Axisymmetric Rocket Based Combined Cycle Engine During Rocket Only Operation Using Linear Regression Analysis

NASA Technical Reports Server (NTRS)

Smith, Timothy D.; Steffen, Christopher J., Jr.; Yungster, Shaye; Keller, Dennis J.

1998-01-01

The all rocket mode of operation is shown to be a critical factor in the overall performance of a rocket based combined cycle (RBCC) vehicle. An axisymmetric RBCC engine was used to determine specific impulse efficiency values based upon both full flow and gas generator configurations. Design of experiments methodology was used to construct a test matrix and multiple linear regression analysis was used to build parametric models. The main parameters investigated in this study were: rocket chamber pressure, rocket exit area ratio, injected secondary flow, mixer-ejector inlet area, mixer-ejector area ratio, and mixer-ejector length-to-inlet diameter ratio. A perfect gas computational fluid dynamics analysis, using both the Spalart-Allmaras and k-omega turbulence models, was performed with the NPARC code to obtain values of vacuum specific impulse. Results from the multiple linear regression analysis showed that for both the full flow and gas generator configurations increasing mixer-ejector area ratio and rocket area ratio increase performance, while increasing mixer-ejector inlet area ratio and mixer-ejector length-to-diameter ratio decrease performance. Increasing injected secondary flow increased performance for the gas generator analysis, but was not statistically significant for the full flow analysis. Chamber pressure was found to be not statistically significant.

A comparative evaluation of explosion hazards in chemical and mechanical pulp bleaching systems

Treesearch

P.W. Hart; Alan Rudie

2010-01-01

Three pulp mills in North America using 50% hydrogen peroxide have suffered explosions of pumps, mixers, and tanks. In two instances, alkali-catalyzed decomposition of peroxide is implicated in the explosion. Although many mechanical pulping facilities use hydrogen peroxide to bleach pulp, no &-catalyzed explosions have been reported. This research uses a kinetic...

ENVIRONMENTAL TECHNOLOGY VERIFICATION JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT PERFORMANCE OF INDUCTION MIXERS FOR DISINFECTION OF WET WEATHER FLOWS, GAS MASTRRR SERIES 32 SUBMERSIBLE CHEMICAL INDUCTION MIXERS

EPA Science Inventory

The Wet-Weather Flow Technologies Pilot of the EPA's Environmental Technology Verification (ETV) Program under a partnership with NSF International has verified the performance of the GAS MASTRRR Series 32 Submersible Chemical Induction Mixers used for disinfection of wet-weather...

A particle tracking method for analyzing chaotic electroosmotic flow mixing in 3D microchannels with patterned charged surfaces

NASA Astrophysics Data System (ADS)

Chang, Chih-Chang; Yang, Ruey-Jen

2006-08-01

This paper presents a numerical simulation investigation into electroosmotic flow mixing in three-dimensional microchannels with patterned non-uniform surface zeta potentials. Three types of micromixers are investigated, namely a straight diagonal strip mixer (i.e. the non-uniform surface zeta potential is applied along straight, diagonal strips on the lower wall of the mixing channel), a staggered asymmetric herringbone strip mixer and a straight diagonal/symmetric herringbone strip mixer. A particle tracing algorithm is used to visualize and evaluate the mixing performance of the various mixers. The particle trajectories and Poincaré maps of the various mixers are calculated from the three-dimensional flow fields. The surface charge patterns on the lower walls of the microchannels induce electroosmotic chaotic advection in the low Reynolds number flow regime, and hence enhance the passive mixing effect in the microfluidic devices. A quantitative measure of the mixing performance based on Shannon entropy is employed to quantify the mixing of two miscible fluids. The results show that the mixing efficiency increases as the magnitude of the heterogeneous zeta potential ratio (|ζR|) is increased, but decreases as the aspect ratio (H/W) is increased. The mixing efficiency of the straight diagonal strip mixer with a length ratio of l/W = 0.5 is slightly higher than that obtained from the same mixer with l/W = 1.0. Finally, the staggered asymmetric herringbone strip mixer with θ = 45°, ζR = -1, l/W = 0.5 and H/W = 0.2 provides the optimal mixing performance of all the mixers presented in this study.

Optimizing micromixer design for enhancing dielectrophoretic microconcentrator performance.

PubMed

Lee, Hsu-Yi; Voldman, Joel

2007-03-01

We present an investigation into optimizing micromixer design for enhancing dielectrophoretic (DEP) microconcentrator performance. DEP-based microconcentrators use the dielectrophoretic force to collect particles on electrodes. Because the DEP force generated by electrodes decays rapidly away from the electrodes, DEP-based microconcentrators are only effective at capturing particles from a limited cross section of the input liquid stream. Adding a mixer can circulate the input liquid, increasing the probability that particles will drift near the electrodes for capture. Because mixers for DEP-based microconcentrators aim to circulate particles, rather than mix two species, design specifications for such mixers may be significantly different from that for conventional mixers. Here we investigated the performance of patterned-groove micromixers on particle trapping efficiency in DEP-based microconcentrators numerically and experimentally. We used modeling software to simulate the particle motion due to various forces on the particle (DEP, hydrodynamic, etc.), allowing us to predict trapping efficiency. We also conducted trapping experiments and measured the capture efficiency of different micromixer configurations, including the slanted groove, staggered herringbone, and herringbone mixers. Finally, we used these analyses to illustrate the design principles of mixers for DEP-based concentrators.

Oxide_Oxide Ceramic Matrix Composite (CMC) Exhaust Mixer Development in the NASA Environmentally Responsible Aviation (ERA) Project

NASA Technical Reports Server (NTRS)

Kiser, James D.; Bansal, Narottam P.; Szelagowski, J.; Sokhey, J.; Heffernan, T.; Clegg, J.; Pierluissi, A.; Riedell, J.; Atmur, S.; Wyen, T.;

A general numerical analysis of the superconducting quasiparticle mixer

NASA Technical Reports Server (NTRS)

Hicks, R. G.; Feldman, M. J.; Kerr, A. R.

1985-01-01

For very low noise millimeter-wave receivers, the superconductor-insulator-superconductor (SIS) quasiparticle mixer is now competitive with conventional Schottky mixers. Tucker (1979, 1980) has developed a quantum theory of mixing which has provided a basis for the rapid improvement in SIS mixer performance. The present paper is concerned with a general method of numerical analysis for SIS mixers which allows arbitrary terminating impedances for all the harmonic frequencies. This analysis provides an approach for an examination of the range of validity of the three-frequency results of the quantum mixer theory. The new method has been implemented with the aid of a Fortran computer program.

Thrust Augmentation with Mixer/Ejector Systems

NASA Technical Reports Server (NTRS)

Presz, Walter M., Jr.; Reynolds, Gary; Hunter, Craig

2002-01-01

Older commercial aircraft often exceed FAA (Federal Aviation Administration) sideline noise regulations. The major problem is the jet noise associated with the high exhaust velocities of the low bypass ratio engines on such aircraft. Mixer/ejector exhaust systems can provide a simple means of reducing the jet noise on these aircraft by mixing cool ambient air with the high velocity engine gases before they are exhausted to ambient. This paper presents new information on thrust performance predictions, and thrust augmentation capabilities of mixer/ejectors. Results are presented from the recent development program of the patented Alternating Lobe Mixer Ejector Concept (ALMEC) suppressor system for the Gulfstream GII, GIIB and GIII aircraft. Mixer/ejector performance procedures are presented which include classical control volume analyses, compound compressible flow theory, lobed nozzle loss correlations and state of the art computational fluid dynamic predictions. The mixer/ejector thrust predictions are compared to subscale wind tunnel test model data and actual aircraft flight test measurements. The results demonstrate that a properly designed mixer/ejector noise suppressor can increase effective engine bypass ratio and generate large thrust gains at takeoff conditions with little or no thrust loss at cruise conditions. The cruise performance obtained for such noise suppressor systems is shown to be a strong function of installation effects on the aircraft.

Concrete Mixing Methods and Concrete Mixers: State of the Art

PubMed Central

Ferraris, Chiara F.

2001-01-01

As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are two main types of mixers used: batch mixers and continuous mixers. Batch mixers are the most common. To determine the mixing method best suited for a specific application, factors to be considered include: location of the construction site (distance from the batching plant), the amount of concrete needed, the construction schedule (volume of concrete needed per hour), and the cost. Ultimately, the quality of the concrete produced determines its performance after placement. An important measure of the quality is the homogeneity of the material after mixing. This paper will review mixing methods in regards to the quality of the concrete produced. Some procedures used to determine the effectiveness of the mixing will be examined. PMID:27500029

The development of mixer machine for organic animal feed production: Proposed study

NASA Astrophysics Data System (ADS)

Leman, A. M.; Wahab, R. Abdul; Zakaria, Supaat; Feriyanto, Dafit; Nor, M. I. F. Che Mohd; Muzarpar, Syafiq

2017-09-01

Mixer machine plays a major role in producing homogenous composition of animal feed. Long time production, inhomogeneous and minor agglomeration has been observed by existing mixer. Therefore, this paper proposed continuous mixer to enhance mixing efficiency with shorter time of mixing process in order to abbreviate the whole process in animal feed production. Through calculation of torque, torsion, bending, power and energy consumption will perform in mixer machine process. Proposed mixer machine is designed by two layer buckets with purpose for continuity of mixing process. Mixing process was performed by 4 blades which consists of various arm length such as 50, 100,150 and 225 mm in 60 rpm velocity clockwise rotation. Therefore by using this machine will produce the homogenous composition of animal feed through nutrition analysis and short operation time of mixing process approximately of 5 minutes. Therefore, the production of animal feed will suitable for various animals including poultry and aquatic fish. This mixer will available for various organic material in animal feed production. Therefore, this paper will highlights some areas such as continues animal feed supply chain and bio-based animal feed.

Electrokinetically driven active micro-mixers utilizing zeta potential variation induced by field effect

NASA Astrophysics Data System (ADS)

Lee, Chia-Yen; Lee, Gwo-Bin; Fu, Lung-Ming; Lee, Kuo-Hoong; Yang, Ruey-Jen

2004-10-01

This paper presents a new electrokinetically driven active micro-mixer which uses localized capacitance effects to induce zeta potential variations along the surface of silica-based microchannels. The mixer is fabricated by etching bulk flow and shielding electrode channels into glass substrates and then depositing Au/Cr thin films within the latter to form capacitor electrodes, which establish localized zeta potential variations near the electrical double layer (EDL) region of the electroosmotic flow (EOF) within the microchannels. The potential variations induce flow velocity changes within a homogeneous fluid and a rapid mixing effect if an alternating electric field is provided. The current experimental data confirm that the fluid velocity can be actively controlled by using the capacitance effect of the buried shielding electrodes to vary the zeta potential along the channel walls. While compared with commonly used planar electrodes across the microchannels, the buried shielding electrodes prevent current leakage caused by bad bonding and allow direct optical observation during operation. It also shows that the buried shielding electrodes can significantly induce the field effect, resulting in higher variations of zeta potential. Computational fluid dynamic simulations are also used to study the fluid characteristics of the developed active mixers. The numerical and experimental results demonstrate that the developed microfluidic device permits a high degree of control over the fluid flow and an efficient mixing effect. Moreover, the developed device could be used as a pumping device as well. The development of the active electrokinetically driven micro-mixer could be crucial for micro-total-analysis-systems.

Design of a mixer for the thrust-vectoring system on the high-alpha research vehicle

NASA Technical Reports Server (NTRS)

Pahle, Joseph W.; Bundick, W. Thomas; Yeager, Jessie C.; Beissner, Fred L., Jr.

1996-01-01

One of the advanced control concepts being investigated on the High-Alpha Research Vehicle (HARV) is multi-axis thrust vectoring using an experimental thrust-vectoring (TV) system consisting of three hydraulically actuated vanes per engine. A mixer is used to translate the pitch-, roll-, and yaw-TV commands into the appropriate TV-vane commands for distribution to the vane actuators. A computer-aided optimization process was developed to perform the inversion of the thrust-vectoring effectiveness data for use by the mixer in performing this command translation. Using this process a new mixer was designed for the HARV and evaluated in simulation and flight. An important element of the Mixer is the priority logic, which determines priority among the pitch-, roll-, and yaw-TV commands.

QCGAT mixer compound exhaust system design and static big model test report

NASA Technical Reports Server (NTRS)

Blackmore, W. L.; Thompson, C. E.

1978-01-01

A mixer exhaust system was designed to meet the proposed performance and exhaust jet noise goals for the AiResearch QCGAT engine. Some 0.35 scale models of the various nozzles were fabricated and aerodynamically and acoustically tested. Preliminary optimization, engine cycle matching, model test data and analysis are presented. A final mixer exhaust system is selected for optimum performance for the overall flight regime.

A comparative evaluation of explosion hazards in chemical and mechanical pulp bleaching systems

Treesearch

Peter W. Hart; Alan W. Rudie

2010-01-01

Over the past several years, at least three pulp mills in North America have experienced catastrophic events that resulted in the explosion of pumps, mixers, and tanks. All these mills were using 50% concentration hydrogen peroxide at the site of the explosions. In at least two instances, alkali catalyzed decomposition of peroxide is implicated in the explosion....

Accurate experimental and theoretical comparisons between superconductor-insulator-superconductor mixers showing weak and strong quantum effects

NASA Technical Reports Server (NTRS)

Mcgrath, W. R.; Richards, P. L.; Face, D. W.; Prober, D. E.; Lloyd, F. L.

1988-01-01

A systematic study of the gain and noise in superconductor-insulator-superconductor mixers employing Ta based, Nb based, and Pb-alloy based tunnel junctions was made. These junctions displayed both weak and strong quantum effects at a signal frequency of 33 GHz. The effects of energy gap sharpness and subgap current were investigated and are quantitatively related to mixer performance. Detailed comparisons are made of the mixing results with the predictions of a three-port model approximation to the Tucker theory. Mixer performance was measured with a novel test apparatus which is accurate enough to allow for the first quantitative tests of theoretical noise predictions. It is found that the three-port model of the Tucker theory underestimates the mixer noise temperature by a factor of about 2 for all of the mixers. In addition, predicted values of available mixer gain are in reasonable agreement with experiment when quantum effects are weak. However, as quantum effects become strong, the predicted available gain diverges to infinity, which is in sharp contrast to the experimental results. Predictions of coupled gain do not always show such divergences.

Turbofan forced mixer lobe flow modeling. Part 3: Application to augment engines

NASA Technical Reports Server (NTRS)

Barber, T.; Moore, G. C.; Blatt, J. R.

1988-01-01

Military engines frequently need large quantities of thrust for short periods of time. The addition of an augmentor can provide such thrust increases but with a penalty of increased duct length and engine weight. The addition of a forced mixer to the augmentor improves performance and reduces the penalty, as well as providing a method for siting the required flame holders. In this report two augmentor concepts are investigated: a swirl-mixer augmentor and a mixer-flameholder augmentor. Several designs for each concept are included and an experimental assessment of one of the swirl-mixer augmentors is presented.

A 30% bandwidth tunerless SIS mixer of quantum-limited sensitivity for Herschel / HIFI Band 1

NASA Astrophysics Data System (ADS)

Salez, Morvan; Delorme, Yan; Peron, I.; Lecomte, Benoit; Dauplay, Frederic; Boussaha, Faouzi; Spatazza, J.; Feret, A.; Krieg, J. M.; Schuster, Karl-Friedrich

2003-02-01

We report on the status of the development of a 30% bandwidth tunerless SIS double-sideband mixer for the "Band 1" (480 GHz-630 GHz) channel of the heterodyne instrument (HIFI) of ESA"s Herschel Space Observatory, scheduled for launch in 2007. After exposing the main features of our mixer design, we present the performance achieved by the demonstration mixer, measured via Fourier Transform Spectroscopy and heterodyne Y factor calibrations. We infer from a preliminary mixer analysis that the mixer has very low, quantum-limited noise and low conversion loss. We also report on some pre-qualification tests, as we currently start to manufacture the qualification models and design the last iteration of masks for SIS junction production.

Submillimeter SIS Mixers Using High Current Density Nb/AIN/Nb Tunnel Junctions and NbTiN Films

NASA Astrophysics Data System (ADS)

Kawamura, J.; Miller, D.; Chen, J.; Kooi, J.; Zmuidzinas, J.; Bumble, B.; Leduc, H.; Stern, J.

1999-03-01

We are currently exploring ways to improve the performance of SIS mixers above 700 GHz. One approach is to use NbTiN in place of Nb for all or some of the mixer circuitry. With its high gap frequency and low losses demonstrated up to 800 GHz, it should be possible to fabricate an all-NbTiN SIS mixer with near quantum-limited noise performance up to 1.2 THz. Using a quasioptical twin-slot two-junction mixer with NbTiN ground plane and wiring and hybrid Nb/A1N/NbTiN junctions, we measured an uncorrected receiver noise temperature of TRx ~ 500 K across 790-850 GHz at 4.2 K bath temperature. Our second approach is to reduce the RC product of the mixer by employing very high current density Nb/A1N/Nb junctions. By using these we will greatly relax the requirement on tuning circuits, which is where substantial losses occur in mixers operating above the Nb gap frequency. These junctions have resistance-area products of R_N*A ~ 5.6 Ohm um2, good subgap to normal resistance ratios, R_sg/R_N ~ 10, and good run-to-run reproducibility. From FTS measurements we infer that omega*R_N*C = 1 at 270 GHz in these junctions. This is a substantial improvement over that available using Nb/Al0x/Nb technology. The sensitivity of a receiver incorporating these high current density mixers is T_Rx = 110 K at 533 GHz using a design for lower J_c mixers, which is close to the best we have measured with lower J_c Nb/Al0x/Nb mixers.

Hand-Portable Gradient Capillary Liquid Chromatography Pumping System.

PubMed

Sharma, Sonika; Plistil, Alex; Barnett, Hal E; Tolley, H Dennis; Farnsworth, Paul B; Stearns, Stanley D; Lee, Milton L

2015-10-20

In this work, a novel splitless nanoflow gradient generator integrated with a stop-flow injector was developed and evaluated using an on-column UV-absorption detector. The gradient pumping system consisted of two nanoflow pumps controlled by micro stepper motors, a mixer connected to a serpentine tube, and a high-pressure valve. The gradient system weighed only 4 kg (9 lbs) and could generate up to 55 MPa (8000 psi) pressure. The system could operate using a 24 V DC battery and required 1.2 A for operation. The total volume capacity of the pump was 74 μL, and a sample volume of 60 nL could be injected. The system provided accurate nanoflow rates as low as 10 nL/min without employing a splitter, making it ideal for capillary column use. The gradient dwell volume was calculated to be 1.3 μL, which created a delay of approximately 4 min with a typical flow rate of 350 nL/min. Gradient performance was evaluated for gradient step accuracy, and excellent reproducibility was obtained in day-to-day experiments (RSD < 1.2%, n = 4). Linear gradient reproducibility was tested by separating a three-component pesticide mixture on a poly(ethylene glycol) diacrylate (PEGDA) monolithic column. The retention time reproducibility was very good in run-to-run experiments (RSD < 1.42%, n = 4). Finally, excellent separation of five phenols was demonstrated using the nanoflow gradient system.

Energy Efficient Engine exhaust mixer model technology report addendum; phase 3 test program

NASA Technical Reports Server (NTRS)

Larkin, M. J.; Blatt, J. R.

1984-01-01

The Phase 3 exhaust mixer test program was conducted to explore the trends established during previous Phases 1 and 2. Combinations of mixer design parameters were tested. Phase 3 testing showed that the best performance achievable within tailpipe length and diameter constraints is 2.55 percent better than an optimized separate flow base line. A reduced penetration design achieved about the same overall performance level at a substantially lower level of excess pressure loss but with a small reduction in mixing. To improve reliability of the data, the hot and cold flow thrust coefficient analysis used in Phases 1 and 2 was augmented by calculating percent mixing from traverse data. Relative change in percent mixing between configurations was determined from thrust and flow coefficient increments. The calculation procedure developed was found to be a useful tool in assessing mixer performance. Detailed flow field data were obtained to facilitate calibration of computer codes.

A Multidisciplinary Approach to Mixer-Ejector Analysis and Design

NASA Technical Reports Server (NTRS)

Hendricks, Eric, S.; Seidel, Jonathan, A.

2012-01-01

The design of an engine for a civil supersonic aircraft presents a difficult multidisciplinary problem to propulsion system engineers. There are numerous competing requirements for the engine, such as to be efficient during cruise while yet quiet enough at takeoff to meet airport noise regulations. The use of mixer-ejector nozzles presents one possible solution to this challenge. However, designing a mixer-ejector which will successfully address both of these concerns is a difficult proposition. Presented in this paper is an integrated multidisciplinary approach to the analysis and design of these systems. A process that uses several low-fidelity tools to evaluate both the performance and acoustics of mixer-ejectors nozzles is described. This process is further expanded to include system-level modeling of engines and aircraft to determine the effects on mission performance and noise near airports. The overall process is developed in the OpenMDAO framework currently being developed by NASA. From the developed process, sample results are given for a notional mixer-ejector design, thereby demonstrating the capabilities of the method.

An effective splitting-and-recombination micromixer with self-rotated contact surface for wide Reynolds number range applications

PubMed Central

Feng, Xiangsong; Ren, Yukun; Jiang, Hongyuan

2013-01-01

It is difficult to mix two liquids on a microfluidic chip because the small dimensions and velocities effectively prevent the turbulence. This paper describes two 2-layer PDMS passive micromixers based on the concept of splitting and recombining the flow that exploits a self-rotated contact surface to increase the concentration gradients to obtain fast and efficient mixing. The designed micromixers were simulated and the mixing performance was assessed. The mixers have shown excellent mixing efficiency over a wide range of Reynolds number. The mixers were reasonably fabricated by multilayer soft lithography, and the experimental measurements were performed to qualify the mixing performance of the realized mixer. The results show that the mixing efficiency for one realized mixer is from 91.8% to 87.7% when the Reynolds number increases from 0.3 to 60, while the corresponding value for another mixer is from 89.4% to 72.9%. It is rather interesting that the main mechanism for the rapid mixing is from diffusion to chaotic advection when the flow rate increases, but the mixing efficiency has not obvious decline. The smart geometry of the mixers with total length of 10.25 mm makes it possible to be integrated with many microfluidic devices for various applications in μ-TAS and Lab-on-a-chip systems. PMID:24396530

An effective splitting-and-recombination micromixer with self-rotated contact surface for wide Reynolds number range applications.

PubMed

Feng, Xiangsong; Ren, Yukun; Jiang, Hongyuan

2013-01-01

It is difficult to mix two liquids on a microfluidic chip because the small dimensions and velocities effectively prevent the turbulence. This paper describes two 2-layer PDMS passive micromixers based on the concept of splitting and recombining the flow that exploits a self-rotated contact surface to increase the concentration gradients to obtain fast and efficient mixing. The designed micromixers were simulated and the mixing performance was assessed. The mixers have shown excellent mixing efficiency over a wide range of Reynolds number. The mixers were reasonably fabricated by multilayer soft lithography, and the experimental measurements were performed to qualify the mixing performance of the realized mixer. The results show that the mixing efficiency for one realized mixer is from 91.8% to 87.7% when the Reynolds number increases from 0.3 to 60, while the corresponding value for another mixer is from 89.4% to 72.9%. It is rather interesting that the main mechanism for the rapid mixing is from diffusion to chaotic advection when the flow rate increases, but the mixing efficiency has not obvious decline. The smart geometry of the mixers with total length of 10.25 mm makes it possible to be integrated with many microfluidic devices for various applications in μ-TAS and Lab-on-a-chip systems.

Plant for producing an oxygen-containing additive as an ecologically beneficial component for liquid motor fuels

DOEpatents

Siryk, Yury Paul; Balytski, Ivan Peter; Korolyov, Volodymyr George; Klishyn, Olexiy Nick; Lnianiy, Vitaly Nick; Lyakh, Yury Alex; Rogulin, Victor Valery

2013-04-30

A plant for producing an oxygen-containing additive for liquid motor fuels comprises an anaerobic fermentation vessel, a gasholder, a system for removal of sulphuretted hydrogen, and a hotwell. The plant further comprises an aerobic fermentation vessel, a device for liquid substance pumping, a device for liquid aeration with an oxygen-containing gas, a removal system of solid mass residue after fermentation, a gas distribution device; a device for heavy gases utilization; a device for ammonia adsorption by water; a liquid-gas mixer; a cavity mixer, a system that serves superficial active and dispersant matters and a cooler; all of these being connected to each other by pipelines. The technical result being the implementation of a process for producing an oxygen containing additive, which after being added to liquid motor fuels, provides an ecologically beneficial component for motor fuels by ensuring the stability of composition fuel properties during long-term storage.

Elastic Valve Using Induced-Charge Electro-Osmosis

NASA Astrophysics Data System (ADS)

Sugioka, Hideyuki

2015-06-01

Biomimic devices using induced-charge electro-osmosis (ICEO) is interesting since they have the possibility to realize high-performance functions with simple structures and with low-energy consumption. Thus, inspired by a cilium, we propose a two-dimensional artificial elastic valve using hydrodynamic force due to ICEO with a thin elastic beam in a microfluidic channel and numerically examine the valving performance. By an implicit strongly coupled simulation technique between a fluid and an elastic structure based on the boundary-element method, along with the thin-double-layer approximation, we realize stable calculations and find that the elastic valve using ICEO functions effectively at high frequency with low applied voltages in a realistic pressure flow. Further, we also examine passive motion of the valve; i.e., it stops a reverse flow effectively and releases a forward flow in the channel. We believe that our device can be used in a wide range of microfluidic applications, such as mixers, pumps, etc.

Frequency locking and monitoring based on Bi-directional terahertz radiation of a 3 rd-order distributed feedback quantum cascade laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Marrewijk, N.; Mirzaei, B.; Hayton, D.

2015-10-07

In this study, we have performed frequency locking of a dual, forward reverse emitting third-order distributed feedback quantum cascade laser (QCL) at 3.5 THz. By using both directions of THz emission in combination with two gas cells and two power detectors, we can for the first time perform frequency stabilization, while monitor the frequency locking quality independently. We also characterize how the use of a less sensitive pyroelectric detector can influence the quality of frequency locking, illustrating experimentally that the sensitivity of the detectors is crucial. Using both directions of terahertz (THz) radiation has a particular advantage for the applicationmore » of a QCL as a local oscillator, where radiation from one side can be used for frequency/phase stabilization, leaving the other side to be fully utilized as a local oscillator to pump a mixer.« less

A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing.

PubMed

Habhab, Mohammed-Baker; Ismail, Tania; Lo, Joe Fujiou

2016-11-23

Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications.

Hot-electron bolometer terahertz mixers for the Herschel Space Observatory.

PubMed

Cherednichenko, Sergey; Drakinskiy, Vladimir; Berg, Therese; Khosropanah, Pourya; Kollberg, Erik

2008-03-01

We report on low noise terahertz mixers (1.4-1.9 THz) developed for the heterodyne spectrometer onboard the Herschel Space Observatory. The mixers employ double slot antenna integrated superconducting hot-electron bolometers (HEBs) made of thin NbN films. The mixer performance was characterized in terms of detection sensitivity across the entire rf band by using a Fourier transform spectrometer (from 0.5 to 2.5 THz, with 30 GHz resolution) and also by measuring the mixer noise temperature at a limited number of discrete frequencies. The lowest mixer noise temperature recorded was 750 K [double sideband (DSB)] at 1.6 THz and 950 K DSB at 1.9 THz local oscillator (LO) frequencies. Averaged across the intermediate frequency band of 2.4-4.8 GHz, the mixer noise temperature was 1100 K DSB at 1.6 THz and 1450 K DSB at 1.9 THz LO frequencies. The HEB heterodyne receiver stability has been analyzed and compared to the HEB stability in the direct detection mode. The optimal local oscillator power was determined and found to be in a 200-500 nW range.

Quantum noise in SIS mixers

NASA Astrophysics Data System (ADS)

Zorin, A. B.

1985-03-01

In the present, quantum-statistical analysis of SIS heterodyne mixer performance, the conventional three-port model of the mixer circuit and the microscopic theory of superconducting tunnel junctions are used to derive a general expression for a noise parameter previously used for the case of parametric amplifiers. This expression is numerically evaluated for various quasiparticle current step widths, dc bias voltages, local oscillator powers, signal frequencies, signal source admittances, and operation temperatures.

Design and analysis of an energy-efficient O-QPSK coherent IR-UWB transceiver with a 0.52° RMS phase-noise fractional synthesizer

NASA Astrophysics Data System (ADS)

Ying, Yutong; Lin, Fujiang; Bai, Xuefei

2018-03-01

This paper explores an energy-efficient pulsed ultra-wideband (UWB) radio-frequency (RF) front-end chip fabricated in 0.18-μm CMOS technology, including a transmitter, receiver, and fractional synthesizer. The transmitter adopts a digital offset quadrature phase-shift keying (O-QPSK) modulator and passive direct-phase multiplexing technology, which are energy- and hardware-efficient, to enhance the data rate for a given spectrum. A passive mixer and a capacitor cross-coupled (CCC) source-follower driving amplifier (DA) are also designed for the transmitter to further reduce the low power consumption. For the receiver, a power-aware low-noise amplifier (LNA) and a quadrature mixer are applied. The LNA adopts a CCC boost common-gate amplifier as the input stage, and its current is reused for the second stage to save power. The mixer uses a shared amplification stage for the following passive IQ mixer. Phase noise suppression of the phase-locked loop (PLL) is achieved by utilizing an even-harmonics-nulled series-coupled quadrature oscillator (QVCO) and an in-band noise-aware charge pump (CP) design. The transceiver achieves a measured data rate of 0.8 Gbps with power consumption of 16 mW and 31.5 mW for the transmitter and the receiver, respectively. The optimized integrated phase noise of the PLL is 0.52° at 4.025 GHz. Project supported by the National Science and Technology Major Project of China (No. 2011ZX03004-002-01).

Low Noise in a Diffusion-Cooled Hot-Electron Mixer at 2.5 THz

NASA Technical Reports Server (NTRS)

Karasik, B. S.; Gaidis, M. C.; McGrath, W. R.; Bumble, B.; LeDuc, H. G.

1997-01-01

The noise performance of a Nb hot-electron bolometer mixer at 2.5 THz has been investigated. The devices are fabricated from a 12-nm-thick Nb film, and have a 0.30 micrometer x 0.15 micrometer in-plane size, thus exploiting diffusion as the electron cooling mechanism. The rf coupling was provided by a twin-slot planar antenna on an elliptical Si lens. The experimentally measured double sideband noise temperature of the receiver was as low as 2750 +/- 250 K with an estimated mixer noise temperature of approximately equal 900 K. The mixer bandwidth derived from both noise bandwidth and IF impedance measurements was approximately equal 1.4 GHz. These results demonstrate the low-noise operation of the diffusion-cooled bolometer mixer above 2 THz.

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions.

PubMed

Hu, Ruien; Crawshaw, John

2017-06-06

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer. The CO2 and crude oil are brought to equilibrium by stirring and circulation and the rheology of the saturated mixture is measured by the rheometer. The system is used to measure the rheological properties of Zuata crude oil (and its toluene dilution) in equilibrium with CO2 at elevated pressures up to 220 bar and a temperature of 50 °C. The results show that CO2 addition changes the oil rheology significantly, initially reducing the viscosity as the CO2 pressure is increased and then increasing the viscosity above a threshold pressure. The non-Newtonian response of the crude is also seen to change with the addition of CO2.

Speaker Recognition Using Real vs. Synthetic Parallel Data for DNN Channel Compensation

DTIC Science & Technology

2016-09-08

Speaker Recognition Using Real vs Synthetic Parallel Data for DNN Channel Compensation Fred Richardson, Michael Brandstein, Jennifer Melot, and...DNNs trained with real Mixer 2 multichannel data perform only slightly better than DNNs trained with synthetic multichannel data for microphone SR on...Mixer 6. Large re- ductions in pooled error rates of 50% EER and 30% min DCF are achieved using DNNs trained on real Mixer 2 data. Nearly the same

Topics in the optimization of millimeter-wave mixers

NASA Technical Reports Server (NTRS)

Siegel, P. H.; Kerr, A. R.; Hwang, W.

1984-01-01

A user oriented computer program for the analysis of single-ended Schottky diode mixers is described. The program is used to compute the performance of a 140 to 220 GHz mixer and excellent agreement with measurements at 150 and 180 GHz is obtained. A sensitivity analysis indicates the importance of various diode and mount characteristics on the mixer performance. A computer program for the analysis of varactor diode multipliers is described. The diode operates in either the reverse biased varactor mode or with substantial forward current flow where the conversion mechanism is predominantly resistive. A description and analysis of a new H-plane rectangular waveguide transformer is reported. The transformer is made quickly and easily in split-block waveguide using a standard slitting saw. It is particularly suited for use in the millimeter-wave band, replacing conventional electroformed stepped transformers. A theoretical analysis of the transformer is given and good agreement is obtained with measurements made at X-band.

Experimental and theoretical characterization of an AC electroosmotic micromixer.

PubMed

Sasaki, Naoki; Kitamori, Takehiko; Kim, Haeng-Boo

2010-01-01

We have reported on a novel microfluidic mixer based on AC electroosmosis. To elucidate the mixer characteristics, we performed detailed measurements of mixing under various experimental conditions including applied voltage, frequency and solution viscosity. The results are discussed through comparison with results obtained from a theoretical model of AC electroosmosis. As predicted from the theoretical model, we found that a larger voltage (approximately 20 V(p-p)) led to more rapid mixing, while the dependence of the mixing on frequency (1-5 kHz) was insignificant under the present experimental conditions. Furthermore, the dependence of the mixing on viscosity was successfully explained by the theoretical model, and the applicability of the mixer in viscous solution (2.83 mPa s) was confirmed experimentally. By using these results, it is possible to estimate the mixing performance under given conditions. These estimations can provide guidelines for using the mixer in microfluidic chemical analysis.

Development of Criteria for the Use of Asphalt-Rubber as a Stress-Absorbing Membrane Interlayer (SAMI).

DTIC Science & Technology

1983-12-01

membrane included " three asphalt-rubber distributor trucks " one asphalt-rubber mixer • one kerosene tanker " one chip spreader " three dump trucks...was recorded with the temperature. 4. The asphalt-rubber was pumped into a spreader truck. The truck temperature, sample temperature, and viscosity...not become clogged. The chip-spreading operation immnedi- ately followed the distributor truck. The chip spreader was immediately fol- lowed by the

Detailed evaluation of the performance of microfluidic T mixers using fluorescence and ultraviolet resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Masca, Sergiu I.; Rodriguez-Mendieta, Iñigo R.; Friel, Claire T.; Radford, Sheena E.; Smith, D. Alastair

2006-05-01

A reliable device that produces efficient mixing with a short dead time has enormous utility in the kinetic analysis of biochemical and chemical processes. We have designed two different T mixers that use moderate flow rates (0.2-0.4ml/s), can monitor reactions up to several milliseconds, and achieve mixing times as low as 20μs. The two mixers are easy to build and dismantle, reliable, and can perform hundreds of experiments without blocking. The first mixer comprises a stainless steel block, containing a microchannel, glued to a quartz cuvette, containing a 200×200μm2 observation channel defining a conventional T mixer. The reactions are monitored by imaging the length of the observation channel onto a charge-coupled device camera. In the second mixer the entire T (200×200μm2 internal cross section) is contained within a 40-mm-long quartz cuvette. We have adopted a novel approach to controlling the entrance channel bore by inserting a stainless steel wire in order to increase the linear speed of the impinging fluids. Using a dye to visualize the flow profile inside the second T mixer, it was shown that in this T geometry segregation of the reactants is observed in the junction between the inlet channels and the observation channel (T junction) and mixing occurs entirely in the observation channel. We thoroughly tested the two mixers through several kinetic reactions using both fluorescence and ultraviolet resonance Raman spectroscopy measurements. We show that both mixers provide efficient mixing with nominal dead times (using 1:10 v /v dilution), calculated using the quenching of the fluorescence of N-acetyl-L-tryptophanamide by N-bromosuccinimide, of 200±20 and 100±10μs, for each mixer, respectively. However, the ability to monitor within the inlet channels and the entire observation channel of the second mixer shows that this standard approach to estimating the dead time is artifactual, since it relies on assuming a constant flow speed throughout the observation channel, a feature that we show is not adhered to at short distances from the T junction. Using both mixers the refolding of the A state of cytochrome c to the native state was followed by fluorescence and ultraviolet resonance Raman spectroscopy, revealing the ability of these instruments to provide insights into the early stages of protein folding using only milligrams of sample.

Mixing monoclonal antibody formulations using bottom-mounted mixers: impact of mechanism and design on drug product quality.

PubMed

Gikanga, Benson; Chen, Yufei; Stauch, Oliver B; Maa, Yuh-Fun

2015-01-01

Using bottom-mounted mixers, particularly those that are magnetically driven, is becoming increasingly common during the mixing process in pharmaceutical and biotechnology manufacturing because of their associated low risk of contamination, ease of use, and ability to accommodate low minimum mixing volumes. Despite these benefits, the impact of bottom-mounted mixers on biologic drug product is not yet fully understood and is scarcely reported. This study evaluated four bottom-mounted mixers to assess their impact on monoclonal antibody formulations. Changes in product quality (size variants, particles, and turbidity) and impact on process performance (sterile filtration) were evaluated after mixing. The results suggested that mixers that are designed to function with no contact between the impeller and the drive unit are the most favorable and gentle to monoclonal antibody molecules. Designs with contact or a narrow clearance tended to shear and grind the protein and resulted in high particle count in the liquid, which would subsequently foul a filter membrane during sterile filtration using a 0.22 μm pore size filter. Despite particle formation, increases in turbidity of the protein solution and protein aggregation/fragmentation were not detected. Further particle analysis indicated particles in the range of 0.2-2 μm are responsible for filter fouling. A small-scale screening model was developed using two types of magnetic stir bars mimicking the presence or absence of contact between the impeller and drive unit in the bottom-mounted mixers. The model is capable of differentiating the sensitivity of monoclonal antibody formulations to bottom-mounted mixers with a small sample size. This study fills an important gap in understanding a critical bioprocess unit operation. Mixing is an important unit operation in drug product manufacturing for compounding (dilution, pooling, homogenization, etc.). The current trend in adopting disposable bottom-mounted mixers has raised concerns about their impact on drug product quality and process performance. However, investigations into the effects of their use for biopharmaceutical products, particularly monoclonal antibody formulations, are rarely published. The purpose of this study is three-fold: (1) to understand the impact of bottom-mounted disposable mixer design on drug product quality and process performance, (2) to identify the mixing mechanism that is most gentle to protein particle formation, (3) to apply the learning to practical mixing operations using bottom-mounted mixers. The outcomes of this study will benefit scientists and engineers who develop biologic product manufacturing process by providing a better understanding of mixing principles and challenges. © PDA, Inc. 2015.

Forced Mixer Nozzle Optimization

NASA Technical Reports Server (NTRS)

Sheoran, Yogi; Hoover, Robert; Schuster, William; Anderson, Morris; Weir, Donald S.

1999-01-01

Computational fluid dynamic (CFD) and computational acoustic analyses (CAA) were performed for a TFE731-40 compound nozzle, a TFE731-60 mixer nozzle and an Energy Efficient Engine (E(sup 3)) mixer nozzle for comparison with available data. The CFD analyses were performed with a three dimensional, Navier-Stokes solution of the flowfield on an unstructured grid using the RAMPANT program. The CAA analyses were performed with the NASA Glenn MGB program using a structured grid. A successful aerodynamic solution for the TFE731-40 compound nozzle operating statically was obtained, simulating an engine operating on a test stand. Analysis of the CFD results of the TFE731-40 with the MGB program produced predicted sound power levels that agree quite well with the measured data front full-scale static engine tests. Comparison of the predicted sound pressure with the data show good agreement near the jet axis, but the noise levels are overpredicted at angles closer to the inlet. The predicted sound power level for the TFE731-60 did not agree as well with measured static engine data as the TFE731-40. Although a reduction in the predicted noise level due to the mixed flow was observed, the reduction was not as significant as the measured data. The analysis of the V2 mixer from the E(sup 3) study showed that peak temperatures predicted in the mixer exit flowfield were within 5 percent of the values measured by the exit probes. The noise predictions of the V2 mixer nozzle tended to be 3-5 dB higher in peak noise level than the measurements. In addition, the maximum frequency of the noise was also overpredicted. An analysis of the 3 candidate mixer nozzle configurations demonstrated the feasibility of using centerbody lobes and porosity to improve mixing efficiency. A final configuration was designed with a predicted thermal mixing efficiency that was 5 percent higher than the 3 candidate mixers. The results of the MGB noise calculations show that the final design will exceed the design goal of a 3 dB reduction in noise as compared to the baseline TFE731-40.

Fabrication of High-T(sub c) Hot-Electron Bolometric Mixers for Terahertz Applications

NASA Technical Reports Server (NTRS)

Burns, M. J.; Kleinsasser, A. W.; Delin, K. A.; Vasquez, R. P.; Karasik, B. S.; McGrath, W. R.; Gaidis, M. C.

1996-01-01

Superocnducting hot-electron bolometers (HEB) represent a promising candidate for heterodyne mixing at frequencies exceeding 1 THz. Nb HEB mixers offer performance competitive with tunnel junctions without the frequency limit imposed by the superconducting energy gap.

CHEMICAL INDUCTION MIXER VERIFICATION - ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM

EPA Science Inventory

The Wet-Weather Flow Technologies Pilot of the Environmental Technology Verification (ETV) Program, which is supported by the U.S. Environmental Protection Agency and facilitated by NSF International, has recently evaluated the performance of chemical induction mixers used for di...

Improved equivalent circuit for twin slot terahertz receivers

NASA Technical Reports Server (NTRS)

McGrath, W. R.

2002-01-01

Series-fed coplanar waveguide embedding circuits are being developed for terahertz mixers using, in particular, submicron-sized superconducting devices, such as hot electron bolometers as the nonlinear element. Although these mixers show promising performance, they usually also show a considerable downward shift in the center frequency, when compared with simulations obtained by using simplified models. This makes it very difficult to design low-noise mixers for a given THz frequency. This shiftis principally caused by parasitics due to the extremely small details (in terms of wavelength) of the device, and by the electrical properties of the RF choke filter in the DC/IF line. In this paper, we present an improved equivalent network model of such mixer circuits which agrees with measured results at THz frequencies and we propose a new set of THz bolometric mixers that have been fabricated and are currently being tested.

Acoustic, Flow Related, and Performance Related Experimental Results for Generation 1.5 High Speed Civil Transport (HSCT) 2-Dimensional Exhaust Nozzles

NASA Technical Reports Server (NTRS)

Salikuddin, M.; Wisler, S.; Majjigi, R.

2004-01-01

The principle objectives of the current program were to experimentally investigate the repeatability of acoustic and aerodynamic characteristics of 2D-CD mixer-ejector nozzles and the effects on the acoustic and aerodynamic characteristics of 2D mixer-ejectors due to (1) the configurational variations, which include mixers with aligned CD chutes, aligned convergent chutes, and staggered CD chutes and aerodynamic cycle variables, (2) treatment variations by using different treatment materials, treating the ejector with varying area, location, and treatment thickness for a mixer-ejector configuration, and (3) secondary inlet shape (i.e., a more realistic inlet) and the blockage across the inlet (a possible fin-like structure needed for installation purpose) by modifying one of the inlet of a mixer-ejector configuration. The objectives also included the measurement dynamic pressures internal to the ejector for a few selected configuration to examine the internal noise characteristics.

An All-Solid-State, Room-Temperature, Heterodyne Receiver for Atmospheric Spectroscopy at 1.2 THz

NASA Technical Reports Server (NTRS)

Siles, Jose V.; Mehdi, Imran; Schlecht, Erich T.; Gulkis, Samuel; Chattopadhyay, Goutam; Lin, Robert H.; Lee, Choonsup; Gill, John J.; Thomas, Bertrand; Maestrini, Alain E.

2013-01-01

Heterodyne receivers at submillimeter wavelengths have played a major role in astrophysics as well as Earth and planetary remote sensing. All-solid-state heterodyne receivers using both MMIC (monolithic microwave integrated circuit) Schottky-diode-based LO (local oscillator) sources and mixers are uniquely suited for long-term planetary missions or Earth climate monitoring missions as they can operate for decades without the need for any active cryogenic cooling. However, the main concern in using Schottky-diode-based mixers at frequencies beyond 1 THz has been the lack of enough LO power to drive the devices because 1 to 3 mW are required to properly pump Schottky diode mixers. Recent progress in HEMT- (high-electron-mobility- transistor) based power amplifier technology, with output power levels in excess of 1 W recently demonstrated at W-band, as well as advances in MMIC Schottky diode circuit technology, have led to measured output powers up to 1.4 mW at 0.9 THz. Here the first room-temperature tunable, all-planar, Schottky-diode-based receiver is reported that is operating at 1.2 THz over a wide (˜20%) bandwidth. The receiver front-end (see figure) consists of a Schottky-diode-based 540 to 640 GHz multiplied LO chain (featuring a cascade of W-band power amplifiers providing around 120 to 180 mW at W-band), a 200-GHz MMIC frequency doubler, and a 600-GHz MMIC frequency tripler, plus a biasable 1.2-THz MMIC sub-harmonic Schottky-diode mixer. The LO chain has been designed, fabricated, and tested at JPL and provides around 1 to 1.5 mW at 540 o 640 GHz. The sub-harmonic mixer consists of two Schottky diodes on a thin GaAs membrane in an anti-parallel configuration. An integrated metal insulator metal (MIM) capacitor has been included on-chip to allow dc bias for the Schottky diodes. A bias voltage of around 0.5 V/diode is necessary to reduce the LO power required down to the 1 to 1.5 mW available from the LO chain. The epilayer thickness and doping profiles have been specifically optimized to maximize the mixer performance beyond 1 THz. The measured DSB noise temperatures and conversion losses of the receiver are 2,000 to 3,500 K and 12 to 14 dB, respectively, at 120 K, and 4,000 to 6,000 K and 13 to 15 dB, respectively, at 300 K. These results establish the state-of-the-art for all-solid-state, all-planar heterodyne receivers at 1.2 THz operating at either room temperature or using passive cooling only. Since no cryogenic cooling is needed, the receiver is eminently suited to atmospheric heterodyne spectroscopy of the outer planets and their moons.

Bubble performance of a novel dissolved air flotation(DAF) unit.

PubMed

Chen, Fu-tai; Peng, Feng-xian; Wu, Xiao-qing; Luan, Zhao-kun

2004-01-01

ES-DAF, a novel DAF with low cost, high reliability and easy controllability, was studied. Without a costly air saturator, ES-DAF consists of an ejector and a static mixer between the pressure side and suction side of the recycle rotary pump. The bubble size distribution in this novel unit was studied in detail by using a newly developed CCD imagination through a microscope. Compared with M-DAF under the same saturation pressure, ES-DAF can produce smaller bubble size and higher bubble volume concentration, especially in lower pressure. In addition, the bubble size decreases with the increase of reflux ratio or decrease of superficial air-water ratio. These results suggested that smaller bubbles will be formed when the initial number of nucleation sites increases by enhancing the turbulence intensity in the saturation system.

A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing

PubMed Central

Habhab, Mohammed-Baker; Ismail, Tania; Lo, Joe Fujiou

2016-01-01

Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications. PMID:27886051

Performance and Uniformity of Mass-Produced SIS Mixers for ALMA Band 8 Receiver Cartridges

NASA Astrophysics Data System (ADS)

Tomura, Tomonuri; Noguchi, Takashi; Sekimoto, Yutaro; Shan, Wenlei; Sato, Naohisa; Iizuka, Yoshizo; Kumagai, Kazuyoshi; Niizeki, Yasuaki; Iwakuni, Mikio; Ito, Tetsuya

2015-05-01

The Atacama large millimeter/submillimeter array (ALMA), which was jointly built in Chile by Europe, North America and East Asia, has an observational band from 30 to 950 GHz [1], [2]. We developed receiver cartridges for ALMA Band 8 (385-500 GHz) [3]-[5] which is one of ALMA 10 frequency bands. The Band 8 receiver cartridges were produced as 73 cartridges, and 292 SIS mixers were installed in their cartridges. Also, their all cartridges were required to meet following ALMA specifications: 1. The noise temperature is less than 196 K over 80% of the frequency range and less than 292 K at any frequency from 385 to 500 GHz. 2. The image rejection ratio is larger than 10 dB over 90% of the frequency range. 3. The IF output power variation is less than 7.0 dB peak-to-peak in the 4-8 GHz band. 4. The gain compression to RF load temperatures between 77 and 373 K is less than 5%. 5. The Allan variance of the IF output power is less than 4.0×10-7 in the time scale of 0.05 s≤T≤100 s and 3.0×10-6 at 300 s. To meet these specifications, the performance and uniformity of the SIS mixers are crucial. The SIS mixers with Nb/Al-AlOx/Nb superconductor-insulator-superconductor (SIS) tunnel junctions were fabricated in a clean room of National Astronomical Observatory of Japan and over 1000 mixer chips were mass-produced. After screening these mixers, 73 Band 8 receivers were assembled and tested. We report the test results of the mass-produced mixers and the receiver cartridges in detail from a statistical point of view.

Terahertz Mixing Characteristics of NbN Superconducting Tunnel Junctions and Related Astronomical Observations

NASA Astrophysics Data System (ADS)

Li, J.

2010-01-01

High-sensitivity superconducting SIS (superconductor-insulator-superconductor) mixers are playing an increasingly important role in the terahertz (THz) astronomical observation, which is an emerging research frontier in modern astrophysics. Superconducting SIS mixers with niobium (Nb) tunnel junctions have reached a sensitivity close to the quantum limit, but have a frequency limit about 0.7 THz (i.e., gap frequency of Nb tunnel junctions). Beyond this frequency Nb superconducting films will absorb energetic photons (i.e., energy loss) to break Cooper pairs, thereby resulting in significant degradation of the mixer performance. Therefore, it is of particular interest to develop THz superconducting SIS mixers incorporating tunnel junctions with a larger energy gap. Niobium-nitride (NbN) superconducting tunnel junctions have been long known for their large energy gap, almost double that of Nb ones. With the introduction of epitaxially grown NbN films, the fabrication technology of NbN superconducting tunnel junctions has been considerably improved in the recent years. Nevertheless, their performances are still not as good as Nb ones, and furthermore they are not yet demonstrated in real astronomical applications. Given the facts mentioned above, in this paper we systematically study the quantum mixing behaviors of NbN superconducting tunnel junctions in the THz regime and demonstrate an astronomical testing observation with a 0.5 THz superconducting SIS mixer developed with NbN tunnel junctions. The main results of this study include: (1) successful design and fabrication of a 0.4˜0.6 THz waveguide mixing circuit with the high-dielectric-constant MgO substrate; (2) successful fabrication of NbN superconducting tunnel junctions with the gap voltage reaching 5.6 mV and the quality factor as high as 15; (3) demonstration of a 0.5 THz waveguide NbN superconducting SIS mixer with a measured receiver noise temperature (no correction) as low as five times the quantum limit (5hω/kB), which is the best among NbN superconducting SIS mixers developed in this frequency band; (4) demonstration of high sensitivity for NbN superconducting SIS mixers operated at temperatures as high as 10 K, and demonstration of much less interference resulting from the Josephson effect; (5) demonstration of the first astronomical observation ever done with an NbN superconducting SIS mixer. This study has provided further understanding of the quantum mixing behaviors of NbN superconducting SIS mixers. It has been demonstrated that NbN superconducting SIS mixers can reach nearly quantum-limited sensitivity and have good stability. Furthermore, NbN superconducting SIS mixers have less stringent requirement for cooling and magnetic field compared with Nb ones. Hence they can be used in astronomical applications, especially for space-borne projects and complex systems such as multi-beam receivers.

Turbofan forced mixer-nozzle internal flowfield. Volume 3: A computer code for 3-D mixing in axisymmetric nozzles

NASA Technical Reports Server (NTRS)

Kreskovsky, J. P.; Briley, W. R.; Mcdonald, H.

1982-01-01

A finite difference method is developed for making detailed predictions of three dimensional subsonic turbulent flow in turbofan lobe mixers. The governing equations are solved by a forward-marching solution procedure which corrects an inviscid potential flow solution for viscous and thermal effects, secondary flows, total pressure distortion and losses, internal flow blockage and pressure drop. Test calculations for a turbulent coaxial jet flow verify that the turbulence model performs satisfactorily for this relatively simple flow. Lobe mixer flows are presented for two geometries typical of current mixer design. These calculations included both hot and cold flow conditions, and both matched and mismatched Mach number and total pressure in the fan and turbine streams.

Method and system to directly produce electrical power within the lithium blanket region of a magnetically confined, deuterium-tritium (DT) fueled, thermonuclear fusion reactor

DOEpatents

Woolley, Robert D.

1999-01-01

A method for integrating liquid metal magnetohydrodynamic power generation with fusion blanket technology to produce electrical power from a thermonuclear fusion reactor located within a confining magnetic field and within a toroidal structure. A hot liquid metal flows from a liquid metal blanket region into a pump duct of an electromagnetic pump which moves the liquid metal to a mixer where a gas of predetermined pressure is mixed with the pressurized liquid metal to form a Froth mixture. Electrical power is generated by flowing the Froth mixture between electrodes in a generator duct. When the Froth mixture exits the generator the gas is separated from the liquid metal and both are recycled.

A 1/10 Scale Model Test of a Fixed Chute Mixer-Ejector Nozzle in Unsuppressed Model. Part 1; Test Overview

NASA Technical Reports Server (NTRS)

Wolter, John D.

2007-01-01

This paper discusses a test of a nozzle concept for a high-speed commercial aircraft. While a great deal of effort has been expended to und erstand the noise-suppressed, take-off performance of mixer-ejector n ozzles, little has been done to assess their performance in unsuppressed mode at other flight conditions. To address this, a 1/10th scale m odel mixer-ejector nozzle in unsuppressed mode was tested at conditio ns representing transonic acceleration, supersonic cruise, subsonic cruise, and approach. Various configurations were tested to understand the effects of acoustic liners and several geometric parameters, such as throat area, expansion ratio, and nozzle length on nozzle performance. Thrust, flow, and internal pressures were measured. A statistica l model of the peak thrust coefficient results is presented and discussed.

A micromixer with consistent mixing performance for a wide range of flow rates.

PubMed

Goovaerts, Robert; Van Assche, Tom; Sonck, Marc; Denayer, Joeri; Desmet, Gert

2015-02-01

A micromixer with consistent mixing performance for a wide range of flow rates is presented. The mixer makes use of internally moving elements, i.e. steel balls that are located in dedicated mixing chambers. Movement is induced by a rotating magnetic field. To get better insight in differences between active and passive mixing, we studied a mixer that can operate in both regimes. A mixing performance study for a range of flow rates along with pressure drop data is presented. The response of the moving elements in regard to the magnetic field is shown experimentally and shows the limitations of earlier modeling studies. Lastly, the estimated power input on the fluids was calculated and allows for a comparison with more well-known convective-type mixers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A compact design for the Josephson mixer: The lumped element circuit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pillet, J.-D.; Collège de France, 11 place Marcelin Berthelot, 75005 Paris; Flurin, E.

2015-06-01

We present a compact and efficient design in terms of gain, bandwidth, and dynamical range for the Josephson mixer, the superconducting circuit performing three-wave mixing at microwave frequencies. In an all lumped-element based circuit with galvanically coupled ports, we demonstrate nondegenerate amplification for microwave signals over a bandwidth up to 50 MHz for a power gain of 20 dB. The quantum efficiency of the mixer is shown to be about 70%, and its saturation power reaches −112 dBm.

An inverted micro-mixer based on a magnetically-actuated cilium made of Fe doped PDMS

NASA Astrophysics Data System (ADS)

Liu, Fengli; Zhang, Jun; Alici, Gursel; Yan, Sheng; Mutlu, Rahim; Li, Weihua; Yan, Tianhong

2016-09-01

In this paper, we report a new micromixer based on a flexible artificial cilium activated by an external magnetic field. The cilium is fabricated from Polydimethylsiloxane doped with Fe microparticles. The fabrication method is based on the standard sacrificial layer technology. The cilium was built on a glass slide, and then was bonded on the top of the micro-mixer chamber in a microfluidic chip. This fabrication process for the miniaturized active mixers is simple and cost effective. An electromagnetic system was used to drive the cilium and induce strong convective flows of the fluid in the chamber. In the presence of an alternating magnetic field, the cilium applied a corresponding alternating force on the surrounding fluids. The performance of the electromagnetically activated cilium was quantified and optimized in order to obtain maximum mixing performance. In addition, the mixing performance of the cilium in a circular micro-chamber was compared with pure diffusion. Up to 80% of a 60 ul liquid in the chamber can be fully mixed after 2 min using a cilium mixer under a magnetic flux density of 22 mT in contrast to the 20 min which were needed to obtain the same mixing percentage under pure diffusion. Furthermore, for a mixing degree of 80%, the mixing speed for the cilia micromixer proposed in this study was 9 times faster than that of the diffusion-based micro-mixers reported in the literature.

AC electroosmotic micromixer for chemical processing in a microchannel.

PubMed

Sasaki, Naoki; Kitamori, Takehiko; Kim, Haeng-Boo

2006-04-01

A rapid micromixer of fluids in a microchannel is presented. The mixer uses AC electroosmotic flow, which is induced by applying an AC voltage to a pair of coplanar meandering electrodes configured in parallel to the channel. To demonstrate performance of the mixer, dilution experiments were conducted using a dye solution in a channel of 120 microm width. Rapid mixing was observed for flow velocity up to 12 mm s(-1). The mixing time was 0.18 s, which was 20-fold faster than that of diffusional mixing without an additional mixing mechanism. Compared with the performance of reported micromixers, the present mixer worked with a shorter mixing length, particularly at low Peclet numbers (Pe < 2 x 10(3)).

A picoliter-volume mixer for microfluidic analytical systems.

PubMed

He, B; Burke, B J; Zhang, X; Zhang, R; Regnier, F E

2001-05-01

Mixing confluent liquid streams is an important, but difficult operation in microfluidic systems. This paper reports the construction and characterization of a 100-pL mixer for liquids transported by electroosmotic flow. Mixing was achieved in a microfabricated device with multiple intersecting channels of varying lengths and a bimodal width distribution. All channels running parallel to the direction of flow were 5 microm in width whereas larger 27-microm-width channels ran back and forth through the parallel channel network at a 45 degrees angle. The channel network composing the mixer was approximately 10 microm deep. It was observed that little mixing of the confluent solvent streams occurred in the 100-microm-wide, 300-microm-long mixer inlet channel where mixing would be achieved almost exclusively by diffusion. In contrast, after passage through the channel network in the approximately 200-microm-length static mixer bed, mixing was complete as determined by confocal microscopy and CCD detection. Theoretical simulations were also performed in an attempt to describe the extent of mixing in microfabricated systems.

Research of UHPC properties prepared with industrial mixer

NASA Astrophysics Data System (ADS)

Šerelis, E.; Vaitkevičius, V.; Kerševičius, V.

2017-09-01

Ultra-high performance concrete (UHPC) mixture with advanced mechanical and durability properties was created using decent Zyklos ZZ50HE mixer. Zyklos ZZ50HE rotating pan mixer is similar to mixer which has common concrete plants. In experiment UHPC was prepared with Zyklos ZZ50HE mixer and thereafter best composition was selected and prepared with industrial HPGM 1125 mixer. Experiment results revealed that UHPC with W/C=0.29 and advanced mechanical and durability properties can be prepared. In experiment tremendous amount of micro steel fibres (up to 147 kg/m3) were incorporated in UHPC. Concrete with excellent salt scaling resistance and great mechanical properties was obtained. Compressive strength was increased about 30 % from 116 MPa to 150 MPa and flexural strength was increased about 5 times from 6.7 to 36.2 MPa. Salt-scaling resistance at 40 cycles in 3 % NaCl solution varied from 0.006 kg/m2 to 0.197 kg/m2. There were a few attempts to create UHPC and UHPFRC with decent technology, however, unsuccessfully till now. In the world practice this new material is currently used in the construction of bridges and viaducts.

Computer design of microfluidic mixers for protein/RNA folding studies.

PubMed

Inguva, Venkatesh; Kathuria, Sagar V; Bilsel, Osman; Perot, Blair James

2018-01-01

Kinetic studies of biological macromolecules increasingly use microfluidic mixers to initiate and monitor reaction progress. A motivation for using microfluidic mixers is to reduce sample consumption and decrease mixing time to microseconds. Some applications, such as small-angle x-ray scattering, also require large (>10 micron) sampling areas to ensure high signal-to-noise ratios and to minimize parasitic scattering. Chaotic to marginally turbulent mixers are well suited for these applications because this class of mixers provides a good middle ground between existing laminar and turbulent mixers. In this study, we model various chaotic to marginally turbulent mixing concepts such as flow turning, flow splitting, and vortex generation using computational fluid dynamics for optimization of mixing efficiency and observation volume. Design iterations show flow turning to be the best candidate for chaotic/marginally turbulent mixing. A qualitative experimental test is performed on the finalized design with mixing of 10 M urea and water to validate the flow turning unsteady mixing concept as a viable option for RNA and protein folding studies. A comparison of direct numerical simulations (DNS) and turbulence models suggests that the applicability of turbulence models to these flow regimes may be limited.

Generation 1.5 High Speed Civil Transport (HSCT) Exhaust Nozzle Program

NASA Technical Reports Server (NTRS)

Thayer, E. B.; Gamble, E. J.; Guthrie, A. R.; Kehret, D. F.; Barber, T. J.; Hendricks, G. J.; Nagaraja, K. S.; Minardi, J. E.

2004-01-01

The objective of this program was to conduct an experimental and analytical evaluation of low noise exhaust nozzles suitable for future High-Speed Civil Transport (HSCT) aircraft. The experimental portion of the program involved parametric subscale performance model tests of mixer/ejector nozzles in the takeoff mode, and high-speed tests of mixer/ejectors converted to two-dimensional convergent-divergent (2-D/C-D), plug, and single expansion ramp nozzles (SERN) in the cruise mode. Mixer/ejector results show measured static thrust coefficients at secondary flow entrainment levels of 70 percent of primary flow. Results of the high-speed performance tests showed that relatively long, straight-wall, C-D nozzles could meet supersonic cruise thrust coefficient goal of 0.982; but the plug, ramp, and shorter C-D nozzles required isentropic contours to reach the same level of performance. The computational fluid dynamic (CFD) study accurately predicted mixer/ejector pressure distributions and shock locations. Heat transfer studies showed that a combination of insulation and convective cooling was more effective than film cooling for nonafterburning, low-noise nozzles. The thrust augmentation study indicated potential benefits for use of ejector nozzles in the subsonic cruise mode if the ejector inlet contains a sonic throat plane.

Experimental Investigation of a Broadband High-Temperature Superconducting Terahertz Mixer Operating at Temperatures Between 40 and 77 K

NASA Astrophysics Data System (ADS)

Gao, Xiang; Du, Jia; Zhang, Ting; Jay Guo, Y.; Foley, Cathy P.

2017-11-01

This paper presents a systematic investigation of a broadband thin-film antenna-coupled high-temperature superconducting (HTS) terahertz (THz) harmonic mixer at relatively high operating temperature from 40 to 77 K. The mixer device chip was fabricated using the CSIRO established step-edge YBa2Cu3O7-x (YBCO) Josephson junction technology, packaged in a well-designed module and cooled in a temperature adjustable cryocooler. Detailed experimental characterizations were carried out for the broadband HTS mixer at both the 200 and 600 GHz bands in harmonic mixing mode. The DC current-voltage characteristics (IVCs), bias current condition, local oscillator (LO) power requirement, frequency response, as well as conversion efficiency under different bath temperatures were thoroughly investigated for demonstrating the frequency down-conversion performance.

THz transceiver characterization : LDRD project 139363 final report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nordquist, Christopher Daniel; Wanke, Michael Clement; Cich, Michael Joseph

2009-09-01

LDRD Project 139363 supported experiments to quantify the performance characteristics of monolithically integrated Schottky diode + quantum cascade laser (QCL) heterodyne mixers at terahertz (THz) frequencies. These integrated mixers are the first all-semiconductor THz devices to successfully incorporate a rectifying diode directly into the optical waveguide of a QCL, obviating the conventional optical coupling between a THz local oscillator and rectifier in a heterodyne mixer system. This integrated mixer was shown to function as a true heterodyne receiver of an externally received THz signal, a breakthrough which may lead to more widespread acceptance of this new THz technology paradigm. Inmore » addition, questions about QCL mode shifting in response to temperature, bias, and external feedback, and to what extent internal frequency locking can improve stability have been answered under this project.« less

EVALUATION AND RECOMMENDATION OF SALTSTONE MIXER AUGER/PADDLES MATERIALS OF CONSTRUCTION FOR IMPROVED WEAR RESISTANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mickalonis, J.; Torres, R.

2012-08-15

Wear and corrosion testing were conducted to evaluate alternate materials of construction for the Saltstone mixer auger and paddles. These components have been degraded by wear from the slurry processed in the mixer. Material test options included PVD coatings (TiN, TiCN, and ZrN), weld overlays (Stellite 12 and Ultimet) and higher hardness steels and carbides (D2 and tungsten carbide). The corrosion testing demonstrated that the slurry is not detrimental to the current materials of construction or the new candidates. The ASTM G75 Miller wear test showed that the high hardness materials and the Stellite 12 weld overlay provide superior wearmore » relative to the Astralloy and CF8M stainless steel, which are the current materials of construction, as well as the PVD coatings and Ultimet. The following recommendations are made for selecting new material options and improving the overall wear resistance of the Saltstone mixer components: A Stellite 12 weld overlay or higher hardness steel (with toughness equivalent to Astralloy) be used to improve the wear resistance of the Saltstone mixer paddles; other manufacturing specifications for the mixer need to be considered in this selection. The current use of the Stellite 12 weld overlay be evaluated so that coverage of the 316 auger can be optimized for improved wear resistance of the auger. The wear surfaces of the Saltstone mixer auger and paddles be evaluated so that laboratory data can be better correlated to actual service. The 2-inch Saltstone mixer prototype be used to verify material performance.« less

Mechanistic Investigation on Grinding-Induced Subvisible Particle Formation during Mixing and Filling of Monoclonal Antibody Formulations.

PubMed

Gikanga, Benson; Hui, Ada; Maa, Yuh-Fun

2018-01-01

Processing equipment involving grinding of two solid surfaces has been demonstrated to induce subvisible particle formation in monoclonal antibody drug product manufacturing processes. This study elucidated potential stress types associated with grinding action to identify the stress mechanism responsible for subvisible particle formation. Several potential stress types can be associated with the grinding action, including interfacial stresses (air-liquid and liquid-solid), hydraulic/mechanical shear stress, cavitation, nucleation of stressed protein molecules, and localized thermal stress. More than one stress type can synergically affect monoclonal antibody product quality, making it challenging to determine the primary mode of stress. Our strategy was to assess and rule out some stress types through platform knowledge, rational judgments, or via small-scale models, for example, rheometer/rotator-stator homogenizer for hydraulic/mechanical shear stress, sonicator for cavitation, etc. These models may not provide direct evidence but can offer rational correlations. Cavitation, as demonstrated by sonication, proved to be quite detrimental to monoclonal antibody molecules in forming not just subvisible particles but also soluble high-molecular-weight species as well as low-molecular-weight species. This outcome was not consistent with that of grinding monoclonal antibodies between the impeller and the drive unit of a bottom-mounted mixer or between the piston and the housing of a rotary piston pump, both of which formed only subvisible particles without obvious high-molecular-weight species and low-molecular-weight species. In addition, a p -nitrophenol model suggested that cavitation in the bottom-mounted mixer is barely detectable. We attributed the grinding-induced, localized thermal effect to be the primary stress to subvisible particle formation based on a high-temperature, spray-drying model. The heat effect of spray drying also caused subvisible particles, in the absence of significant high-molecular-weight species and low-molecular-weight species, in spray-dried monoclonal antibody powders. This investigation provides a mechanistic understanding of the underlying stress mechanism leading to monoclonal antibody subvisible particle formation as the result of drug product processing involving grinding of solid surfaces. LAY ABSTRACT: Subvisible particles present in therapeutic protein formulations could adversely affect drug product safety and efficacy. We previously illustrated that grinding action of the solid surfaces in some bottom-mounted mixers and piston pump is responsible for subvisible particle formation of monoclonal antibody formulations. In this study, we delved into mechanistic understanding of the stress types associated with solid surface grinding. The approach was to employ several scale-down stress models with known stress types. Protein formulations stressed in these models were analytically characterized for subvisible particles and other degradants. Some commonly known stress types-such as air-liquid interface, mechanical stress, cavitation, nucleation, and thermal effect-were assessed in this study. The stress model yielding a degradation profile matching that of bottom-mounted mixers and piston pump warranted further assessment. Localized, thermal stress proved to be the most feasible mechanism. This study, along with previously published results, may further advance our understanding of these particular drug product manufacturing processes and benefit scientists and engineers in overcoming these development challenges. © PDA, Inc. 2018.

High-Tc superconducting microbolometer for terahertz applications

NASA Astrophysics Data System (ADS)

Ulysse, C.; Gaugue, A.; Adam, A.; Kreisler, A. J.; Villégier, J.-C.; Thomassin, J.-L.

2002-05-01

Superconducting hot electron bolometer mixers are now a competitive alternative to Schottky diode mixers in the terahertz frequency range because of their ultra wideband (from millimeter waves to visible light), high conversion gain, and low intrinsic noise level. High Tc superconductor materials can be used to make hot electron bolometers and present some advantage in term of operating temperature and cooling. In this paper, we present first a model for the study of superconducting hot electron bolometers responsivity in direct detection mode, in order to establish a firm basis for the design of future THz mixers. Secondly, an original process to realize YBaCuO hot electron bolometer mixers will be described. Submicron YBaCuO superconducting structures are expitaxially sputter deposited on MgO substrates and patterned by using electron beam lithography in combination with optical lithography. Metal masks achieved by electron beam lithography are insuring a good bridge definition and protection during ion etching. Finally, detection experiments are being performed with a laser at 850 nm wavelength, in homodyne mode in order to prove the feasibility and potential performances of these devices.

Ceramic membrane ozonator for soluble organics removal from produced water

NASA Astrophysics Data System (ADS)

Siagian, U. W. R.; Dwipramana, A. S.; Perwira, S. B.; Khoiruddin; Wenten, I. G.

2018-01-01

In this work, the performance of ozonation for degradation of soluble organic compounds in produced water was investigated. Tubular ceramic membrane diffuser (with and without a static mixer in the lumen side) was used to facilitate contact between ozone and produced water. The ozonation was conducted at ozone flow rate of 8 L.min-1, ozone concentration of 0.4 ppm, original pH of the solution, and pressure of 1.2 bar, while the flow rates of the produced water were varied (192, 378 and 830 mL.min-1). It was found that the reduction of benzene, toluene, ethylbenzene, and xylene were 85%, 99%, 85%, and 95%, respectively. A lower liquid flow rate in a laminar state showed a better component reduction due to the longer contacting time between the liquid and the gas phase. The introduction of the static mixer in the lumen side of the membrane as a turbulence promoter provided a positive effect on the performance of the membrane diffuser. The twisted static mixer exhibited the better removal rate than the spiral static mixer.

Holographic optical tweezers for object manipulations at an air-liquid surface.

PubMed

Jesacher, Alexander; Fürhapter, Severin; Maurer, Christian; Bernet, Stefan; Ritsch-Marte, Monika

2006-06-26

We investigate holographic optical tweezers manipulating micro-beads at a suspended air-liquid interface. Axial confinement of the particles in the two-dimensional interface is maintained by the interplay between surface tension and gravity. Therefore, optical trapping of the micro-beads is possible even with a long distance air objective. Efficient micro-circulation of the liquid can be induced by fast rotating beads, driven by the orbital angular momentum transfer of incident Laguerre-Gaussian (doughnut) laser modes. Our setup allows various ways of creating a tailored dynamic flow of particles and liquid within the surface. We demonstrate examples of surface manipulations like efficient vortex pumps and mixers, interactive particle flow steering by arrays of vortex pumps, the feasibility of achieving a "clocked" traffic of micro beads, and size-selective guiding of beads along optical "conveyor belts".

Implementation of an optimized microfluidic mixer in alumina employing femtosecond laser ablation

NASA Astrophysics Data System (ADS)

Juodėnas, M.; Tamulevičius, T.; Ulčinas, O.; Tamulevičius, S.

2018-01-01

Manipulation of liquids at the lowest levels of volume and dimension is at the forefront of materials science, chemistry and medicine, offering important time and resource saving applications. However, manipulation by mixing is troublesome at the microliter and lower scales. One approach to overcome this problem is to use passive mixers, which exploit structural obstacles within microfluidic channels or the geometry of channels themselves to enforce and enhance fluid mixing. Some applications require the manipulation and mixing of aggressive substances, which makes conventional microfluidic materials, along with their fabrication methods, inappropriate. In this work, implementation of an optimized full scale three port microfluidic mixer is presented in a slide of a material that is very hard to process but possesses extreme chemical and physical resistance—alumina. The viability of the selected femtosecond laser fabrication method as an alternative to conventional lithography methods, which are unable to process this material, is demonstrated. For the validation and optimization of the microfluidic mixer, a finite element method (FEM) based numerical modeling of the influence of the mixer geometry on its mixing performance is completed. Experimental investigation of the laminar flow geometry demonstrated very good agreement with the numerical simulation results. Such a laser ablation microfabricated passive mixer structure is intended for use in a capillary force assisted nanoparticle assembly setup (CAPA).

Lobed Mixer Design for Noise Suppression Acoustic and Aerodynamic Test Data Analysis

NASA Technical Reports Server (NTRS)

Mengle, Vinod G.; Dalton, William N.; Boyd, Kathleen (Technical Monitor); Bridges, James (Technical Monitor)

2002-01-01

A comprehensive database for the acoustic and aerodynamic characteristics of several model-scale lobe mixers of bypass ratio 5 to 6 has been created for mixed jet speeds up to 1080 ft/s at typical take-off (TO) conditions of small-to-medium turbofan engines. The flight effect was simulated for Mach numbers up to 0.3. The static thrust performance and plume data were also obtained at typical TO and cruise conditions. The tests were done at NASA Lewis anechoic dome and ASK's FluiDyne Laboratories. The effect of several lobe mixer and nozzle parameters, such as, lobe scalloping, lobe count, lobe penetration and nozzle length was examined in terms of flyover noise at constant altitude. Sound in the nozzle reference frame was analyzed to understand the source characteristics. Several new concepts, mechanisms and methods are reported for such lobed mixers, such as, "boomerang" scallops, "tongue" mixer, detection of "excess" internal noise sources, and extrapolation of flyover noise data from one flight speed to different flight speeds. Noise reduction of as much as 3 EPNdB was found with a deeply scalloped mixer compared to annular nozzle at net thrust levels of 9500 lb for a 29 in. diameter nozzle after optimizing the nozzle length.

Analysis of Fuel Vaporization, Fuel-Air Mixing, and Combustion in Integrated Mixer-Flame Holders

NASA Technical Reports Server (NTRS)

Deur, J. M.; Cline, M. C.

2004-01-01

Requirements to limit pollutant emissions from the gas turbine engines for the future High-Speed Civil Transport (HSCT) have led to consideration of various low-emission combustor concepts. One such concept is the Integrated Mixer-Flame Holder (IMFH). This report describes a series of IMFH analyses performed with KIVA-II, a multi-dimensional CFD code for problems involving sprays, turbulence, and combustion. To meet the needs of this study, KIVA-II's boundary condition and chemistry treatments are modified. The study itself examines the relationships between fuel vaporization, fuel-air mixing, and combustion. Parameters being considered include: mixer tube diameter, mixer tube length, mixer tube geometry (converging-diverging versus straight walls), air inlet velocity, air inlet swirl angle, secondary air injection (dilution holes), fuel injection velocity, fuel injection angle, number of fuel injection ports, fuel spray cone angle, and fuel droplet size. Cases are run with and without combustion to examine the variations in fuel-air mixing and potential for flashback due to the above parameters. The degree of fuel-air mixing is judged by comparing average, minimum, and maximum fuel/air ratios at the exit of the mixer tube, while flame stability is monitored by following the location of the flame front as the solution progresses from ignition to steady state. Results indicate that fuel-air mixing can be enhanced by a variety of means, the best being a combination of air inlet swirl and a converging-diverging mixer tube geometry. With the IMFH configuration utilized in the present study, flashback becomes more common as the mixer tube diameter is increased and is instigated by disturbances associated with the dilution hole flow.

High density 3D printed microfluidic valves, pumps, and multiplexers.

PubMed

Gong, Hua; Woolley, Adam T; Nordin, Gregory P

2016-07-07

In this paper we demonstrate that 3D printing with a digital light processor stereolithographic (DLP-SLA) 3D printer can be used to create high density microfluidic devices with active components such as valves and pumps. Leveraging our previous work on optical formulation of inexpensive resins (RSC Adv., 2015, 5, 106621), we demonstrate valves with only 10% of the volume of our original 3D printed valves (Biomicrofluidics, 2015, 9, 016501), which were already the smallest that have been reported. Moreover, we show that incorporation of a thermal initiator in the resin formulation along with a post-print bake can dramatically improve the durability of 3D printed valves up to 1 million actuations. Using two valves and a valve-like displacement chamber (DC), we also create compact 3D printed pumps. With 5-phase actuation and a 15 ms phase interval, we obtain pump flow rates as high as 40 μL min(-1). We also characterize maximum pump back pressure (i.e., maximum pressure the pump can work against), maximum flow rate (flow rate when there is zero back pressure), and flow rate as a function of the height of the pump outlet. We further demonstrate combining 5 valves and one DC to create a 3-to-2 multiplexer with integrated pump. In addition to serial multiplexing, we also show that the device can operate as a mixer. Importantly, we illustrate the rapid fabrication and test cycles that 3D printing makes possible by implementing a new multiplexer design to improve mixing, and fabricate and test it within one day.

Gen 2.0 Mixer/Ejector Nozzle Test at LSAF June 1995 to July 1996

NASA Technical Reports Server (NTRS)

Arney, L. D.; Sandquist, D. L.; Forsyth, D. W.; Lidstone, G. L.; Long-Davis, Mary Jo (Technical Monitor)

2005-01-01

Testing of the HSCT Generation 2.0 nozzle model hardware was conducted at the Boeing Low Speed Aeroacoustic Facility, LSAF. Concurrent measurements of noise and thrust were made at critical takeoff design conditions for a variety of mixer/ejector model hardware. Design variables such as suppressor area ratio, mixer area ratio, liner type and thickness, ejector length, lobe penetration, and mixer chute shape were tested. Parallel testing was conducted at G.E.'s Cell 41 acoustic free jet facility to augment the LSAF test. The results from the Gen 2.0 testing are being used to help shape the current nozzle baseline configuration and guide the efforts in the upcoming Generation 2.5 and 3.0 nozzle tests. The Gen 2.0 results have been included in the total airplane system studies conducted at MDC and Boeing to provide updated noise and thrust performance estimates.

Instrumentation for submillimeter spectroscopy; Proceedings of the Meeting, Cannes, France, December 5, 6, 1985

NASA Technical Reports Server (NTRS)

Kollberg, Eric (Editor)

1986-01-01

The design and performance of spectroscopic instruments for submm-wave astronomy are discussed in reviews and reports. Topics examined include superconducting mixers, Schottky-diode mixers, local oscillators, antennas and quasi-optical components, spectrometry, and systems aspects. Special emphasis is given to candidate components for the 8-m heterodyne FIR and Submm Space Telescope being developed by ESA.

THz Local Oscillator Technology

NASA Technical Reports Server (NTRS)

Mehdi, Imran

2004-01-01

The last decade has seen a number of technological advancements that have now made it possible to implement fully solid state local oscillator chains up to 2 THz. These chains are composed of cascaded planar multiplier stages that are pumped with W-band high power sources. The high power W-band sources are achieved by power combining MMIC amplifiers and can provide in access of 150 mW with about 10% bandwidth. Planar diode technology has also enabled novel circuit topologies that can take advantage of the high input power and demonstrate significant efficiencies well into the THz range. Cascaded chains to 1.9 THz have now been demonstrated with enough output power to successfully pump hot-electron bolometer mixers in this frequency range. An overview of the current State-of-the-Art of the local oscillator technology will be presented along with highlighting future trends and challenges.

Commercial Submersible Mixing Pump For SRS Tank Waste Removal - 15223

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hubbard, Mike; Herbert, James E.; Scheele, Patrick W.

The Savannah River Site Tank Farms have 45 active underground waste tanks used to store and process nuclear waste materials. There are 4 different tank types, ranging in capacity from 2839 m 3 to 4921 m 3 (750,000 to 1,300,000 gallons). Eighteen of the tanks are older style and do not meet all current federal standards for secondary containment. The older style tanks are the initial focus of waste removal efforts for tank closure and are referred to as closure tanks. Of the original 51 underground waste tanks, six of the original 24 older style tanks have completed waste removalmore » and are filled with grout. The insoluble waste fraction that resides within most waste tanks at SRS requires vigorous agitation to suspend the solids within the waste liquid in order to transfer this material for eventual processing into glass filled canisters at the Defense Waste Processing Facility (DWPF). SRS suspends the solid waste by use of recirculating mixing pumps. Older style tanks generally have limited riser openings which will not support larger mixing pumps, since the riser access is typically 58.4 cm (23 inches) in diameter. Agitation for these tanks has been provided by four long shafted standard slurry pumps (SLP) powered by an above tank 112KW (150 HP) electric motor. The pump shaft is lubricated and cooled in a pressurized water column that is sealed from the surrounding waste in the tank. Closure of four waste tanks has been accomplished utilizing long shafted pump technology combined with heel removal using multiple technologies. Newer style waste tanks at SRS have larger riser openings, allowing the processing of waste solids to be accomplished with four large diameter SLPs equipped with 224KW (300 HP) motors. These tanks are used to process the waste from closure tanks for DWPF. In addition to the SLPs, a 224KW (300 HP) submersible mixer pump (SMP) has also been developed and deployed within older style tanks. The SMPs are product cooled and product lubricated canned motor pumps designed to fit within available risers and have significant agitation capabilities to suspend waste solids. Waste removal and closure of two tanks has been accomplished with agitation provided by 3 SMPs installed within the tanks. In 2012, a team was assembled to investigate alternative solids removal technologies to support waste removal for closing tanks. The goal of the team was to find a more cost effective approach that could be used to replace the current mixing pump technology. This team was unable to identify an alternative technology outside of mixing pumps to support waste agitation and removal from SRS waste tanks. However, the team did identify a potentially lower cost mixing pump compared to the baseline SLPs and SMPs. Rather than using the traditional procurement using an engineering specification, the team proposed to seek commercially available submersible mixer pumps (CSMP) as alternatives to SLPs and SMPs. SLPs and SMPs have a high procurement cost and the actual cost of moving pumps between tanks has shown to be significantly higher than the original estimates that justified the reuse of SMPs and SLPs. The team recommended procurement of “off-the-shelf” industry pumps which may be available for significant savings, but at an increased risk of failure and reduced operating life in the waste tank. The goal of the CSMP program is to obtain mixing pumps that could mix from bulk waste removal through tank closure and then be abandoned in place as part of tank closure. This paper will present the development, progress and relative advantages of the CSMP.« less

Method of achieving ultra-wideband true-time-delay beam steering for active electronically scanned arrays

DOEpatents

Loui, Hung; Brock, Billy C.

2016-10-25

The various embodiments presented herein relate to beam steering an array antenna by modifying intermediate frequency (IF) waveforms prior to conversion to RF signals. For each channel, a direct digital synthesis (DDS) component can be utilized to generate a waveform or modify amplitude, timing and phase of a waveform relative to another waveform, whereby the generation/modification can be performed prior to the IF input port of a mixer on each channel. A local oscillator (LO) signal can be utilized to commonly drive each of the mixers. After conversion at the RF output port of each of the mixers, each RF signal can be transmitted by a respective antenna element in the antenna array. Initiation of transmission of each RF signal can be performed simultaneously at each antenna. The process can be reversed during receive whereby timing, amplitude, and phase of the received can be modified digitally post ADC conversion.

Metriwave final report

NASA Technical Reports Server (NTRS)

Williams, Wyman

1991-01-01

The superconductor-insulator-superconductor (SIS) mixer is a device which is being used in the construction of very sensitive receivers in the millimeter and submillimeter wavelength regions. With its potential for conversion gain and quantum-limited performance, it is becoming a device of prime importance in radio astronomy as well as earth and planetary atmospheric research. Many of the parameters of the SIS mixer cannot be readily measured in the laboratory, however, since most commercially available test instruments use test signal powers large enough to saturate or destroy SIS junctions. Detailed here is the construction of a microwave network analyzer with extremely low test signal powers. The results of a development performed by Dynamics Technology, Inc., under a Phase 2 SBIR contract from NASA (NAS7-1025) are documented. The work resulted in a network analyzer to be delivered to workers at the Jet Propulsion Laboratory, which should be capable of SIS mixer characterization in support of their ongoing work in this area.

High-k Scattering Receiver Mixer Performance for NSTX-U

NASA Astrophysics Data System (ADS)

Barchfeld, Robert; Riemenschneider, Paul; Domier, Calvin; Luhmann, Neville; Ren, Yang; Kaita, Robert

2016-10-01

The High-k Scattering system detects primarily electron-scale turbulence k θ spectra for studying electron thermal transport in NSTX-U. A 100 mW, 693 GHz probe beam passes through plasma, and scattered power is detected by a 4-pixel quasi optical, mixer array. Remotely controlled receiving optics allows the scattering volume to be located from core to edge with a k θ span of 7 to 40 cm-1. The receiver array features 4 RF diagonal input horns, where the electric field polarization is aligned along the diagonal of a square cross section horn, at 30 mm channel spacing. The local oscillator is provided by a 14.4 GHz source followed by a x48 multiplier chain, giving an intermediate frequency of 1 GHz. The receiver optics receive 4 discreet scattering angles simultaneously, and then focus the signals as 4 parallel signals to their respective horns. A combination of a steerable probe beam, and translating receiver, allows for upward or downward scattering which together can provide information about 2D turbulence wavenumber spectrum. IF signals are digitized and stored for later computer analysis. The performance of the receiver mixers is discussed, along with optical design features to enhance the tuning and performance of the mixers. Work supported in part by U.S. DOE Grant DE-FG02-99ER54518 and DE-AC02-09CH1146.

Turbofan forced mixer lobe flow modeling. 1: Experimental and analytical assessment

NASA Technical Reports Server (NTRS)

Barber, T.; Paterson, R. W.; Skebe, S. A.

1988-01-01

A joint analytical and experimental investigation of three-dimensional flowfield development within the lobe region of turbofan forced mixer nozzles is described. The objective was to develop a method for predicting the lobe exit flowfield. In the analytical approach, a linearized inviscid aerodynamical theory was used for representing the axial and secondary flows within the three-dimensional convoluted mixer lobes and three-dimensional boundary layer analysis was applied thereafter to account for viscous effects. The experimental phase of the program employed three planar mixer lobe models having different waveform shapes and lobe heights for which detailed measurements were made of the three-dimensional velocity field and total pressure field at the lobe exit plane. Velocity data was obtained using Laser Doppler Velocimetry (LDV) and total pressure probing and hot wire anemometry were employed to define exit plane total pressure and boundary layer development. Comparison of data and analysis was performed to assess analytical model prediction accuracy. As a result of this study a planar mixed geometry analysis was developed. A principal conclusion is that the global mixer lobe flowfield is inviscid and can be predicted from an inviscid analysis and Kutta condition.

433 micron laser heterodyne observations of galactic CO from Mauna Kea

NASA Technical Reports Server (NTRS)

Buhl, D.; Chin, G.; Koepf, G. A.; Fetterman, H. R.; Peck, D. D.; Clifton, B. J.; Tannenwald, P. E.; Goldsmith, P. F.; Erickson, N. R.; Mcavoy, N.

1981-01-01

A submillimeter heterodyne radiometer, developed for astronomical applications, uses an optically pumped laser local oscillator and a quasi-optical Schottky diode mixer. The resultant telescope-mounted system, which has a noise temperature less than 4000 K (double sideband) and high frequency and spatial resolution, has been used to detect the J = 6 to 5 rotational transition of carbon monoxide at 434 micrometers in the Orion molecular clouds. The measurements, when compared with previous millimeter-wave data, indicate that the broad carbon monoxide emission feature is produced by an optically thin gas whose temperature exceeds 180 K.

Microfluidic active mixers employing ultra-high aspect-ratio rare-earth magnetic nano-composite polymer artificial cilia

NASA Astrophysics Data System (ADS)

Rahbar, Mona; Shannon, Lesley; Gray, Bonnie L.

2014-02-01

We present a new micromixer based on highly magnetic, flexible, high aspect-ratio, artificial cilia that are fabricated as individual micromixer elements or in arrays for improved mixing performance. These new cilia enable high efficiency, fast mixing in a microchamber, and are controlled by small electromagnetic fields. The artificial cilia are fabricated using a new micromolding process for nano-composite polymers. Cilia fibers with aspect-ratios as high as 8:0.13 demonstrate the fabrication technique's capability in creating ultra-high aspect-ratio microstructures. Cilia, which are realized in polydimethylsiloxane doped with rare-earth magnetic powder, are magnetized to produce permanent magnetic structures with bidirectional deflection capabilities, making them highly suitable as mixers controlled by electromagnetic fields. Due to the high magnetization level of the polarized nano-composite polymer, we are able to use miniature electromagnets providing relatively small magnetic fields of 1.1 to 7 mT to actuate the cilia microstructures over a very wide motion range. Mixing performances of a single cilium, as well as different arrays of multiple cilia ranging from 2 to 8 per reaction chamber, are characterized and compared with passive diffusion mixing performance. The mixer cilia are actuated at different amplitudes and frequencies to optimize mixing performance. We demonstrate that more than 85% of the total volume of the reaction chamber is fully mixed after 3.5 min using a single cilium mixer at 7 mT compared with only 20% of the total volume mixed with passive diffusion. The time to achieve over 85% mixing is further reduced to 70 s using an array of eight cilia microstructures. The novel microfabrication technique and use of rare-earth permanently-magnetizable nano-composite polymers in mixer applications has not been reported elsewhere by other researchers. We further demonstrate improved mixing over other cilia micromixers as enabled by the high aspect-ratio, high flexibility, and magnetic properties of our cilia micromixer elements.

ENVIRONMENTAL TECHNOLOGY VERIFICATION JOINT (NSF-EPA) VERIFICATION STATEMENT AND REPORT, PERFORMANCE OF INDUCTION MIXERS FOR DISINFECTION OF WET WEATHER FLOWS, US FILTER/STRANCO PRODUCTS WATER CHAMP R F SERIES CHEMICAL INDUCTION SYSTEM

EPA Science Inventory

The Wet-Weather Flow Technologies Pilot of the EPA's Technology Verification (ETV) Program under a partnership with NSF International has verified the performawnce of the USFilter/Stranco Products chemical induction mixer used for disinfection of wet-weather flows. The USFilter t...

A millimeter wave Josephson mixer employing a high-T(c) GdBaCuO point contact

NASA Technical Reports Server (NTRS)

Olsson, H. K.; Claeson, T.; Eriksson, S.; Johansson, L.-G.; Mcgrath, W. R.

1987-01-01

A Josephson effect heterodyne mixer for the millimeter wave band was investigated employing high-T(c) GdBaCuO point contacts. Mixer performance was in qualitative agreement with theory. A mixing response was observed up to 55 K, the highest operating temperature achieved for such a device to date. The voltage separation of RF-induced steps gave a value of h/2e = 2.08 x 10 to the -15th V s, which is in excellent agreement with the value expected for Cooper pairs. In addition, the temperature dependence of the I(0)R product was found to agree with Bardeen-Cooper-Schrieffer theory in the weak coupling limit.

Modeling and Optimization of a High-Tc Hot-Electron Superconducting Mixer for Terahertz Applicaitons

NASA Technical Reports Server (NTRS)

Karasik, B. S.; McGrath, W. R.; Gaidis, M. C.; Burns, M. J.; Kleinsasser, A. W.; Delin, K. A.; Vasquez, R. P.

1996-01-01

The development of a YBa(sub 2)Cu(sub 3)O(sub 7-(kronecker delta))(YBCO) hot-electron bolometer (HEB) quasioptical mixer for a 2.5 heterodyne receiver is discussed. The modeled device is a submicron bridge made from a 10 nm thick film on a high thermal conductance substrate. The mixer performance expected for this device is analyzed in the framework of a two-temperature model which includes heating both of the electrons and the lattice. Also, the contribution of heat diffusion from the film through the substrate and from the film to the normal metal contacts is evaluated....a single sideband temperature of less than 2000k is predicted.

Acceptance test report, 241-SY-101 Flexible Receiver System, Phase 2 testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ritter, G.A.

1995-02-06

This document summarizes the results of the Phase 2 acceptance test of the 241-SY-101 Flexible Receiver System (FRS). The FRS is one of six major components of the Equipment Removal System, which has been designed to retrieve, transport, and store the test mixer pump currently installed in Tank 241-SY-101. The purpose of this acceptance test is to verify the strength of the containment bag and bag bottom cinching mechanism. It is postulated that 68 gallons of waste could be trapped inside the pump internals. The bag must be capable of supporting this waste if it shakes loose and drains tomore » the bottom of the bag after the bag bottom has been cinched closed. This acceptance test was performed at the Maintenance and Storage Facility (MASF) Facility in the 400 area on January 23, 1995. The bag assembly supported the weight of 920 kg (2,020 lbs) of water with no leakage or damage to the bag. This value meets the acceptance criteria of 910 kg of water and therefore the results were found to be acceptable. The maximum volume of liquid expected to be held up in the pump internals is 258 L (68 gallons), which corresponds to 410 kg. This test weight gives just over a safety factor of 2. The bag also supported a small shock load while it was filled with water when the crane hoisted the bag assembly up and down. Based on the strength rating of the bag components, the bag assembly should support 2--3 times the test weight of 910 kg.« less

Proof-of-concept automation of propellant processing

NASA Technical Reports Server (NTRS)

Ramohalli, Kumar; Schallhorn, P. A.

1989-01-01

For space-based propellant production, automation of the process is needed. Currently, all phases of terrestrial production have some form of human interaction. A mixer was acquired to help perform the tasks of automation. A heating system to be used with the mixer was designed, built, and installed. Tests performed on the heating system verify design criteria. An IBM PS/2 personal computer was acquired for the future automation work. It is hoped that some the mixing process itself will be automated. This is a concept demonstration task; proving that propellant production can be automated reliably.

Planar Submillimeter-Wave Mixer Technology with Integrated Antenna

NASA Technical Reports Server (NTRS)

Chattopadhyay, Gautam; Mehdi, Imran; Gill, John J.; Lee, Choonsup; lombart, Muria L.; Thomas, Betrand

2010-01-01

High-performance mixers at terahertz frequencies require good matching between the coupling circuits such as antennas and local oscillators and the diode embedding impedance. With the availability of amplifiers at submillimeter wavelengths and the need to have multi-pixel imagers and cameras, planar mixer architecture is required to have an integrated system. An integrated mixer with planar antenna provides a compact and optimized design at terahertz frequencies. Moreover, it leads to a planar architecture that enables efficient interconnect with submillimeter-wave amplifiers. In this architecture, a planar slot antenna is designed on a thin gallium arsenide (GaAs) membrane in such a way that the beam on either side of the membrane is symmetric and has good beam profile with high coupling efficiency. A coplanar waveguide (CPW) coupled Schottky diode mixer is designed and integrated with the antenna. In this architecture, the local oscillator (LO) is coupled through one side of the antenna and the RF from the other side, without requiring any beam sp litters or diplexers. The intermediate frequency (IF) comes out on a 50-ohm CPW line at the edge of the mixer chip, which can be wire-bonded to external circuits. This unique terahertz mixer has an integrated single planar antenna for coupling both the radio frequency (RF) input and LO injection without any diplexer or beamsplitters. The design utilizes novel planar slot antenna architecture on a 3- mthick GaAs membrane. This work is required to enable future multi-pixel terahertz receivers for astrophysics missions, and lightweight and compact receivers for planetary missions to the outer planets in our solar system. Also, this technology can be used in tera hertz radar imaging applications as well as for testing of quantum cascade lasers (QCLs).

Testing of a Spray-Bar Zero Gravity Cryogenic Vent System for Upper Stages

NASA Technical Reports Server (NTRS)

Lak, Tibor; Flachbart, Robin; Nguyen, Han; Martin, James

1999-01-01

The capability to vent in zero gravity without resettling is a fundamental technology need that involves practically all uses of subcritical cryogenics in space. Venting without resettling would extend cryogenic orbital transfer vehicle capabilities. However, the lack of definition regarding liquid/ullage orientation coupled with the somewhat random nature of the thermal stratification and resulting pressure rise rates, lead to significant technical challenges. Typically a zero gravity vent concept, termed a thermodynamic vent system (TVS), consists of a tank mixer to destratify the propellant, combined with a Joule- Thomson (J-T) valve to extract then-nal energy from the propellant. In a cooperative effort, Marshall Space Flight Center's (MSFC's) Multipurpose Hydrogen Test Bed (N4HTB) was used to test a unique "spray bar" TVS system developed by Boeing. A schematic of this system is included in Figure 1. The system consists of a recirculation pump, a parallel flow concentric tube, heat exchanger, and a spray bar positioned close to the longitudinal axis of the tank. In the mixing mode, the recirculation pump withdraws liquid from the tank and sprays it radially into the tank liquid, ullage, and exposed tank surfaces. When energy extraction is required, a small portion of the recirculated liquid is passed sequentially through the J-T expansion valve, the spray bar heat exchanger element, and is vented overboard. The vented vapor cools the circulated bulk fluid, thereby removing thermal energy and reducing tank pressure. Figure 2 is a plot of ullage pressure (P4) and liquid vapor pressure (PSAI) versus time. The pump operates alone, cycling on and off, to destratify the tank liquid and ullage until the liquid vapor pressure reaches the lower set point. At that point, the J-T valve begins to cycle on and off with the pump. Thus, for short duration missions, only the mixer may operate, thus minimizing or even eliminating boil-off losses. The primary advantage of the spray bar configuration is that pressure reduction is achieved independent of liquid and vapor location, thereby enhancing the applicability of normal gravity test data to zero gravity conditions. The in-tank components are minimized with the proposed TVS design. Because the recirculation pump is external to the tank, no electrical power penetration of the tank is required for pump or valve operation. This is especially desirable for L02 tanks since the presence of an electrical ignition source in oxygen represents a critical failure mode. Also, since the critical components (pump, motor, valve, orifice) are external to the tank, system checkout and ground servicing/replacement are easier. For zero-g operation, component replacement external to the tank may be a significant benefit. In addition to satisfying the zero g TVS design objectives, the TVS concept tested offers additional benefits to the integrated subcritical cryogenic storage and launch system.

Improvement of mass transfer characteristics and productivities of inclined tubular photobioreactors by installation of internal static mixers.

PubMed

Ugwu, C U; Ogbonna, J C; Tanaka, H

2002-04-01

The feasibility of improving mass transfer characteristics of inclined tubular photobioreactors by installation of static mixers was investigated. The mass transfer characteristics of the tubular photobioreactor varied depending on the type (shape) and the number of static mixers. The volumetric oxygen transfer coefficient ( k(L)a) and gas hold up of the photobioreactor with internal static mixers were significantly higher than those of the photobioreactor without static mixers. The k(L)a and gas hold up increased with the number of static mixers but the mixing time became longer due to restricted liquid flow through the static mixers. By installing the static mixers, the liquid flow changed from plug flow to turbulent mixing so that cells were moved between the surface and bottom of the photobioreactor. In outdoor culture of Chlorella sorokiniana, the photobioreactor with static mixers gave higher biomass productivities irrespective of the standing biomass concentration and solar radiation. The effectiveness of the static mixers (average percentage increase in the productivities of the photobioreactor with static mixers over the productivities obtained without static mixers) was higher at higher standing biomass concentrations and on cloudy days (solar radiation below 6 MJ m(-2) day(-1)).

Mixing Study in a Multi-dimensional Motion Mixer

NASA Astrophysics Data System (ADS)

Shah, R.; Manickam, S. S.; Tomei, J.; Bergman, T. L.; Chaudhuri, B.

2009-06-01

Mixing is an important but poorly understood aspect in petrochemical, food, ceramics, fertilizer and pharmaceutical processing and manufacturing. Deliberate mixing of granular solids is an essential operation in the production of industrial powder products usually constituted from different ingredients. The knowledge of particle flow and mixing in a blender is critical to optimize the design and operation. Since performance of the product depends on blend homogeneity, the consequence of variability can be detrimental. A common approach to powder mixing is to use a tumbling blender, which is essentially a hollow vessel horizontally attached to a rotating shaft. This single axis rotary blender is one of the most common batch mixers among in industry, and also finds use in myriad of application as dryers, kilns, coaters, mills and granulators. In most of the rotary mixers the radial convection is faster than axial dispersion transport. This slow dispersive process hinders mixing performance in many blending, drying and coating applications. A double cone mixer is designed and fabricated which rotates around two axes, causing axial mixing competitive to its radial counterpart. Discrete Element Method (DEM) based numerical model is developed to simulate the granular flow within the mixer. Digitally recorded mixing states from experiments are used to fine tune the numerical model. Discrete pocket samplers are also used in the experiments to quantify the characteristics of mixing. A parametric study of the effect of vessel speeds, relative rotational speed (between two axes of rotation), on the granular mixing is investigated by experiments and numerical simulation. Incorporation of dual axis rotation enhances axial mixing by 60 to 85% in comparison to single axis rotation.

Very high-current-density Nb/AlN/Nb tunnel junctions for low-noise submillimeter mixers

NASA Astrophysics Data System (ADS)

Kawamura, Jonathan; Miller, David; Chen, Jian; Zmuidzinas, Jonas; Bumble, Bruce; LeDuc, Henry G.; Stern, Jeff A.

2000-04-01

We have fabricated and tested submillimeter-wave superconductor-insulator-superconductor (SIS) mixers using very high-current-density Nb/AlN/Nb tunnel junctions (Jc≈30 kA cm-2). The junctions have low-resistance-area products (RNA≈5.6 Ω μm2), good subgap-to-normal resistance ratios Rsg/RN≈10, and good run-to-run reproducibility. From Fourier transform spectrometer measurements, we infer that ωRNC=1 at 270 GHz. This is a factor of 2.5 improvement over what is generally available with Nb/AlOx/Nb junctions suitable for low-noise mixers. The AlN-barrier junctions are indeed capable of low-noise operation: we measure an uncorrected double-sideband receiver noise temperature of TRX=110 K at 533 GHz for an unoptimized device. In addition to providing wider bandwidth operation at lower frequencies, the AlN-barrier junctions will considerably improve the performance of THz SIS mixers by reducing rf loss in the tuning circuits.

A general numerical analysis program for the superconducting quasiparticle mixer

NASA Technical Reports Server (NTRS)

Hicks, R. G.; Feldman, M. J.; Kerr, A. R.

1986-01-01

A user-oriented computer program SISCAP (SIS Computer Analysis Program) for analyzing SIS mixers is described. The program allows arbitrary impedance terminations to be specified at all LO harmonics and sideband frequencies. It is therefore able to treat a much more general class of SIS mixers than the widely used three-frequency analysis, for which the harmonics are assumed to be short-circuited. An additional program, GETCHI, provides the necessary input data to program SISCAP. The SISCAP program performs a nonlinear analysis to determine the SIS junction voltage waveform produced by the local oscillator. The quantum theory of mixing is used in its most general form, treating the large signal properties of the mixer in the time domain. A small signal linear analysis is then used to find the conversion loss and port impedances. The noise analysis includes thermal noise from the termination resistances and shot noise from the periodic LO current. Quantum noise is not considered. Many aspects of the program have been adequately verified and found accurate.

The effect of fuel/air mixer design parameters on the continuous and discrete phase structure in the reaction-stabilizing region

NASA Astrophysics Data System (ADS)

Ateshkadi, Arash

The demands on current and future aero gas turbine combustors are demanding a greater insight into the role of the injector/dome design on combustion performance. The structure of the two-phase flow and combustion performance associated with practical injector/dome hardware is thoroughly investigated. A spray injector with two radial inflow swirlers was custom-designed to maintain tight tolerances and strict assembly protocol to isolate the sensitivity of performance to hardware design. The custom set is a unique modular design that (1) accommodates parametric variation in geometry, (2) retains symmetry, and (3) maintains effective area. Swirl sense and presence of a venturi were found to be the most influential on fuel distribution and Lean Blowout. The venturi acts as a fuel-prefilming surface and constrains the highest fuel mass concentration to an annular ring near the centerline. Co-swirl enhances the radial dispersion of the continuous phase and counter-swirl increases the level of mixing that occurs in the downstream region of the mixer. The smallest drop size distributions were found to occur with the counter-swirl configuration with venturi. In the case of counter-swirl without venturi the high concentration of fluid mass is found in the center region of the flow. The Lean Blowout (LBO) equivalence ratio was lower for counter-swirl due to the coupling of the centerline recirculation zone with the location of high fuel concentration emanating from smaller droplets. In the co-swirl configuration a more intense reaction was found near the mixer exit leading to the lowest concentration of NOx, CO and UHC. An LBO model with good agreement to the measured values was developed that related, for the first time, specific hardware parameters and operating condition to stability performance. A semi-analytical model, which agreed best with co-swirl configurations, was modified and used to describe the axial velocity profile downstream of the mixer exit. The development of these two models exemplifies the use of mathematical expressions to guide the design and development procedure for mixer geometry that meet the stringent demands on increasing combustion performance.

Effective Thermo-Capillary Mixing in Droplet Microfluidics Integrated with a Microwave Heater.

PubMed

Yesiloz, Gurkan; Boybay, Muhammed S; Ren, Carolyn L

2017-02-07

In this study, we present a microwave-based microfluidic mixer that allows rapid mixing within individual droplets efficiently. The designed microwave mixer is a coplanar design with a small footprint, which is fabricated on a glass substrate and integrated with a microfluidic chip. The mixer works essentially as a resonator that accumulates an intensive electromagnetic field into a spiral capacitive gap (around 200 μm), which provides sufficient energy to heat-up droplets that pass through the capacitive gap. This microwave actuation induces nonuniform Marangoni stresses on the interface, which results in three-dimensional motion inside the droplet and thus fast mixing. In order to evaluate the performance of the microwave mixer, droplets with highly viscous fluid, 75% (w/w) glycerol solution, were generated, half of which were seeded with fluorescent dye for imaging purposes. The relative importance of different driving forces for mixing was evaluated qualitatively using magnitude analysis, and the effect of the applied power on mixing performance was also investigated. Mixing efficiency was quantified using the mixing index, which shows as high as 97% mixing efficiency was achieved within the range of milliseconds. This work demonstrates a very unique approach of utilizing microwave technology to facilitate mixing in droplet microfluidics systems, which can potentially open up areas for biochemical synthesis applications.

Mixer assembly for a gas turbine engine having a pilot mixer with a corner flame stabilizing recirculation zone

NASA Technical Reports Server (NTRS)

Dai, Zhongtao (Inventor); Cohen, Jeffrey M. (Inventor); Fotache, Catalin G. (Inventor)

2012-01-01

A mixer assembly for a gas turbine engine is provided, including a main mixer, and a pilot mixer having an annular housing in which a corner is formed between an aft portion of the housing and a bulkhead wall in which a corner recirculation zone is located to stabilize and anchor the flame of the pilot mixer. The pilot mixer can further include features to cool the annular housing, including in the area of the corner recirculation zone.

Alternate paddle configuration for improved wear resistance in the saltstone mixer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.; Fowley, M.

The Saltstone Production Facility has a 10-inch Readco-Kurimoto continuous mixer that mixes the premix dry feeds and low-level waste salt solution to make fresh (uncured) saltstone. Inspection of the mixer in January 2013 showed significant wear on the third, fourth and fifth paddle pairs after the conveying augers. A 2-inch Readco-Kurimoto continuous mixer was used to test alternate paddle configurations for use in the 10-inch mixer to decrease the wear rate on the paddles. Two wear tests were conducted to investigate a method of reducing wear on the mixer paddles. The first test (wear test 2a) had a paddle configurationmore » similar to the currently installed 10-inch mixer in the SPF. This test established baseline wear. The second test (wear test 2b) had a reconfigured paddle arrangement that replaced the flat paddles with helical paddles for paddle pairs 2 - 6 and aligned paddle pair 1 with the augers. The intent of the reconfiguration was to more effectively convey the partially wetted dry feeds through the transition region and into the liquid feed where paddle wear is reduced due to dry feeds and salt solution being mixed at the intended water to premix ratio. The design of the helical paddles provides conveyance through the transition region to the liquid feed inlet. The alignment with the auger is aimed to provide a smoother transition (minimizing the discontinuity between the auger and paddle pair 1) into the downstream paddles. A soft metal with low wear resistance (6000 series aluminum) was used for the wear testing paddles to determine wear patterns while minimizing run time and maximizing wear rate. For the two paddle configurations tested using the scaled 2-inch Readco-Kurimoto continuous mixer, with the first six paddles after the augers replaced by the wear paddles and the remaining paddles were stainless steel. Since the 10-inch SPF mixer is designed with the liquid inlet centered over paddle pairs 5 and 6, the scaled 2-inch mixer was configured the same way. The wear rate from wear test 2a was approximately double the wear rate from wear test 2b for paddle pairs 4 and 5. For both configurations, there was little or no wear on paddle pairs 1, 2, 3 and 6 based on mass change, indicating that the un-wetted and fully wetted premix materials cause less wear than the partially wetted premix. Additionally, inspection of the wear surface of the paddles showed more deformation on the flat paddles than the helical paddles which was consistent with the wear rates. Aligning of the auger discharge flight with paddle pair 1 resulted in a lower wear rate paddle pair 1 rather than having them misaligned with the feed augers. During the paddle wear tests, polishing wear was observed on the inside barrel of the mixer. The polishing wear is evident on the upper housing clamshell and the lower housing clamshell primarily at paddle pairs 4 and 5, which is the transition region of the mixer. Wear on the mixer barrel increases the space between the paddles and the barrel, resulting in increased grout build up on the barrel. Since the mixer barrel cannot be reconfigured or replaced in the SPF, the method for mitigating wear on the barrel is to move the more viscous grout through the transition region as quickly as possible. In addition, the location of the liquid inlet does not allow for sufficient cleaning of the mixer since residual grout remains on paddle pairs 1 - 4. As the paddles continue to wear and the self-cleaning capability of the paddles is lost, the lack of sufficient flushing would aid in grout build up between the barrel and the paddles which could eventually lead to decreased throughput capacity of the dry feeds. Changing the paddle configuration from flat to helical resulted in no change to the rheological properties of the grout mixture. Both tests produced a grout that is within the processing range of the SPF. Based on the results of this testing, it is recommended for the currently installed SPF mixer that paddle pairs 1 through 6 be helical rather than flat, with the paddle pair 1 aligned with the feed augers in order to minimize the wear occurring in the SPF mixer. Based on the results of this testing, it is recommended that the mixer be inspected and critical measurements be taken whenever the SPF processing schedule allows in order to establish a wear rate of the 10-inch mixer paddles.5 Based on these measurements, the lifetime of paddles in the transition region can be established in order to set up a maintenance schedule for the mixer. Since replacing the entire mixer is very expensive and time intensive, replacing the worn paddles after a specific time period would allow for planned shutdowns as well as process optimization such that the mixer throughput is not compromised. In addition, further testing should be performed to determine an alternate liquid inlet location to better flush the mixer of residual grout at the end of processing. Sufficiently cleaning the mixer will help eliminate another potential source of wear. Another potential method for reducing the wear rate in the mixer is to reduce the mixer speed without affecting the throughput capacity. Since wear rate is a function of impact velocity of the grout and mixing paddles, testing could be done using the 2-inch mixer determine the optimum mixer speed to reduce wear but not adversely impact facility operations (e.g. throughput capacity and grout properties).« less

Bluff Body Fuel Mixer

NASA Technical Reports Server (NTRS)

Cheung, Albert K. (Inventor); Hoke, James B. (Inventor); McKinney, Randal G. (Inventor)

2017-01-01

A combustor is provided. The combustor may include an axial fuel injection system, and a radial fuel injection system aft of the axial fuel injection system. The axial fuel injection system includes a mixer having a bluff body at an exit port of the mixer, and a fuel injector disposed within the mixer. A fuel and air mixer is also provided and comprises an outer housing with an exit port and a bluff body. The bluff body extends across the exit port of the outer housing. A fuel injection system is also provided. The systems comprise a mixer having a bluff body at an exit port of the mixer and a fuel injector disposed within the mixer.

A Matlab-Based Graphical User Interface for Simulation and Control Design of a Hydrogen Mixer

NASA Technical Reports Server (NTRS)

Richter, Hanz; Figueroa, Fernando

2003-01-01

A Graphical User Interface (GUI) that facilitates prediction and control design tasks for a propellant mixer is described. The Hydrogen mixer is used in rocket test stand operations at the NASA John C. Stennis Space Center. The mixer injects gaseous hydrogen (GH2) into a stream of liquid hydrogen (LH2) to obtain a combined flow with desired thermodynamic properties. The flows of GH2 and LH2 into the mixer are regulated by two control valves, and a third control valve is installed at the exit of the mixer to regulate the combined flow. The three valves may be simultaneously operated in order to achieve any desired combination of total flow, exit temperature and mixer pressure within the range of operation. The mixer, thus, constitutes a three-input, three-output system. A mathematical model of the mixer has been obtained and validated with experimental data. The GUI presented here uses the model to predict mixer response under diverse conditions.

Ionic electroactive polymer actuators as active microfluidic mixers

DOE PAGES

Meis, Catherine; Montazami, Reza; Hashemi, Nastaran

2015-11-06

On-chip sample processing is integral to the continued development of lab-on-a-chip devices for various applications. An active microfluidic mixer prototype is proposed using ionic electroactive polymer actuators (IEAPAs) as artificial cilia. A proof-of-concept experiment was performed in which the actuators were shown to produce localized flow pattern disruptions in the laminar flow regime. Suggestions for further engineering and optimization of a scaled-down, complete device are provided. Furthermore, the device in its current state of development necessitates further engineering, the use of IEAPAs addresses issues currently associated with the use of electromechanical actuators as active microfluidic mixers and may prove tomore » be a useful alternative to other similar materials.« less

Fiber-optic delay-line stabilization of heterodyne optical signal generator and method using same

NASA Technical Reports Server (NTRS)

Logan, Ronald T. (Inventor)

1997-01-01

The present invention is a laser heterodyne frequency generator system with a stabilizer for use in the microwave and millimeter-wave frequency ranges utilizing a photonic mixer as a photonic phase detector in a stable optical fiber delay-line. Phase and frequency fluctuations of the heterodyne laser signal generators are stabilized at microwave and millimeter wave frequencies by a delay line system operating as a frequency discriminator. The present invention is free from amplifier and mixer 1/.function. noise at microwave and millimeter-wave frequencies that typically limit phase noise performance in electronic cavity stabilized electronic oscillators. Thus, 1/.function. noise due to conventional mixers is eliminated and stable optical heterodyne generation of electrical signals is achieved.

Analysis of a Rocket Based Combined Cycle Engine during Rocket Only Operation

NASA Technical Reports Server (NTRS)

Smith, T. D.; Steffen, C. J., Jr.; Yungster, S.; Keller, D. J.

1998-01-01

The all rocket mode of operation is a critical factor in the overall performance of a rocket based combined cycle (RBCC) vehicle. However, outside of performing experiments or a full three dimensional analysis, there are no first order parametric models to estimate performance. As a result, an axisymmetric RBCC engine was used to analytically determine specific impulse efficiency values based upon both full flow and gas generator configurations. Design of experiments methodology was used to construct a test matrix and statistical regression analysis was used to build parametric models. The main parameters investigated in this study were: rocket chamber pressure, rocket exit area ratio, percent of injected secondary flow, mixer-ejector inlet area, mixer-ejector area ratio, and mixer-ejector length-to-inject diameter ratio. A perfect gas computational fluid dynamics analysis was performed to obtain values of vacuum specific impulse. Statistical regression analysis was performed based on both full flow and gas generator engine cycles. Results were also found to be dependent upon the entire cycle assumptions. The statistical regression analysis determined that there were five significant linear effects, six interactions, and one second-order effect. Two parametric models were created to provide performance assessments of an RBCC engine in the all rocket mode of operation.

Practical development of continuous supercritical fluid process using high pressure and high temperature micromixer

NASA Astrophysics Data System (ADS)

Kawasaki, Shin-Ichiro; Sue, Kiwamu; Ookawara, Ryuto; Wakashima, Yuichiro; Suzuki, Akira

2015-12-01

In the synthesis of metal oxide fine particles by continuous supercritical hydrothermal method, the particle characteristics are greatly affected by not only the reaction conditions (temperature, pressure, residence time, concentration, etc.), but also the heating rate from ambient to reaction temperature. Therefore, the heating method by direct mixing of starting solution at room temperature with supercritical water is a key technology for the particle production having smaller size and narrow distribution. In this paper, mixing engineering study through comparison between conventional T-shaped mixers and recently developed swirl mixers was carried out in the hydrothermal synthesis of NiO nanoparticles from Ni(NO3)2 aqueous solution at 400 °C and 30 MPa. Inner diameter in the mixers and total flow rates were varied. Furthermore, the heating rate was calculated by computational fluid dynamics (CFD) simulation. Relationship between the heating rate and the average particle size were discussed. It was clarified that the miniaturization of mixer inner diameter and the use of the swirl flow were effective for improving mixing performance and contributed to produce small and narrow distribution particle under same experimental condition of flow rate, temperature, pressure, residence time, and concentration of the starting materials. We have focused the mixer optimization due to a difference in fluid viscosity.

Third order intermodulation distortion in HTS Josephson Junction downconverter at 12GHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Katsumi; Hayashi, Kunihiko; Fujimoto, Manabu

1994-12-31

Here the authors first report on the microwave characteristics of the third order intermodulation distortion(IMD3) in High-Tc Superconductor (HTS) Josephson Junction (JJ) Downconverter at 12GHz. They have successfully developed high quality nonlinear YBCO microbridge Josephson junctions for such an active MMIC as a mixer with RF, LO, IF and bias filters, which have been fabricated on (100) MgO substrates with 20mm x 20mm x 0.5mm dimensions. The minimum conversion loss of the JJ mixer is 11 dB at very small local microwave input power LO= {minus}20dBm which is two order less than Schottky diode mixer. Consequently, this small optimum LOmore » power gives the small RF input power at which the output IF power of the YBCO mixer saturates. Two-tone third-order intercept point(IP3) performance is a significantly important figure of merit typically used to define linearity of devices and circuits. The RF input power = {minus}15dBm at the IP3 point is obtained for the YBCO mixer at 15K and LO = 10.935GHz with {minus}22dBm. The have successfully measured the dependence of IMD3 on temperature, bias current and LO power.« less

Slush hydrogen quantity gaging and mixing for the National Aerospace Plane

NASA Astrophysics Data System (ADS)

Rudland, R. S.; Kroenke, I. M.; Urbach, A. R.

The National Aerospace Plane (NASP) design team has selected slush hydrogen as the fuel needed to power the high-speed ramjet-scramjet engines. Use of slush hydrogen rather than normal hydrogen provides significant improvements in density and cooling capacity for the aircraft. The loading of slush hydrogen in the NASP tank must be determined accurately to allow the vehicle size and weight to be kept to a minimum. A unique sensor developed at Ball to measure the slush density will be used in each region of the hydrogen tank to accurately determine the total mass of fuel loaded in the vehicle. The design, analysis, and test configuration for the mixing system is described in this paper. The mixing system is used to eliminate large-scale disturbances in the fluid produced by the large heat flux through the wall. The mixer also provides off-bottom suspension of the solids to create a more uniform slush mixture. The mixer design uses a pump to supply flow to an array of jets that produce mixing throughout the tank. Density sensors will be used in the test configuration to evaluate the mixing effectiveness.

Air-induction aspirator-aerators cut heat loss to the atmosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodel, A.E.

1993-04-01

The efficiency of biological treatment at the Amoco Chemical's Cedar Bayou plant's activated-sludge wastewater-treatment system was reduced when outdoor temperatures fell below 65[degrees]F. Amoco experienced microbe fragmenting and failure to settle in final clarification, especially during winter. Meeting permit standards during winter was a concern. With mechanical aerators, water is pumped upward and thrown into the air. Much heat loss in the aerated basin was from evaporation and conduction of the mechanical aerator spray. The plant's wastewater staff decided to replace the aerators with subsurface, propeller-type aerator-mixers. These air-induction, aspirating aerator-mixers employ a system that eliminates the spray action throughmore » which evaporation and conduction can occur. The aspirator-aeration systems also have saved energy. The units do not have to overcome the forces of gravity, as with mechanical, surface splasher aerators, which required more horsepower and higher energy consumption to throw the water up into the air. The new units can be conveniently turned on and off to match a fluctuating flow. Since the Cedar Bayou plant installed the system, the aspirator-aerators' subsurface mixing capabilities have made winter permit compliance a steadfast routine.« less

Electrochemical cell apparatus having an exterior fuel mixer nozzle

DOEpatents

Reichner, Philip; Doshi, Vinod B.

1992-01-01

An electrochemical apparatus (10) is made having a generator section (22) containing electrochemical cells (16), a fresh gaseous feed fuel inlet (28), a gaseous feed oxidant inlet (30), and at least one hot gaseous spent fuel recirculation channel (46), where the spent fuel recirculation channel (46), a portion of which is in contact with the outside of a mixer chamber (52), passes from the generator chamber (22) to combine with the fresh feed fuel inlet (28) at the entrance to the mixer chamber, and a mixer nozzle (50) is located at the entrance to the mixer chamber, where the mixer chamber (52) connects with the reforming chamber (54), and where the mixer-diffuser chamber (52) and mixer nozzle (50) are exterior to and spaced apart from the combustion chamber (24), and the generator chamber (22), and the mixer nozzle (50) can operate below 400.degree. C.

Flashback resistant pre-mixer assembly

DOEpatents

Laster, Walter R [Oviedo, FL; Gambacorta, Domenico [Oviedo, FL

2012-02-14

A pre-mixer assembly associated with a fuel supply system for mixing of air and fuel upstream from a main combustion zone in a gas turbine engine. The pre-mixer assembly includes a swirler assembly disposed about a fuel injector of the fuel supply system and a pre-mixer transition member. The swirler assembly includes a forward end defining an air inlet and an opposed aft end. The pre-mixer transition member has a forward end affixed to the aft end of the swirler assembly and an opposed aft end defining an outlet of the pre-mixer assembly. The aft end of the pre-mixer transition member is spaced from a base plate such that a gap is formed between the aft end of the pre-mixer transition member and the base plate for permitting a flow of purge air therethrough to increase a velocity of the air/fuel mixture exiting the pre-mixer assembly.

STME Hydrogen Mixer Study

NASA Technical Reports Server (NTRS)

Blumenthal, Rob; Kim, Dongmoon; Bache, George

1992-01-01

The hydrogen mixer for the Space Transportation Main Engine is used to mix cold hydrogen bypass flow with warm hydrogen coolant chamber gas, which is then fed to the injectors. It is very important to have a uniform fuel temperature at the injectors in order to minimize mixture ratio problems due to the fuel density variations. In addition, the fuel at the injector has certain total pressure requirements. In order to achieve these objectives, the hydrogen mixer must provide a thoroughly mixed fluid with a minimum pressure loss. The AEROVISC computational fluid dynamics (CFD) code was used to analyze the STME hydrogen mixer, and proved to be an effective tool in optimizing the mixer design. AEROVISC, which solves the Reynolds Stress-Averaged Navier-Stokes equations in primitive variable form, was used to assess the effectiveness of different mixer designs. Through a parametric study of mixer design variables, an optimal design was selected which minimized mixed fuel temperature variation and fuel mixer pressure loss. The use of CFD in the design process of the STME hydrogen mixer was effective in achieving an optimal mixer design while reducing the amount of hardware testing.

A novel in-plane passive microfluidic mixer with modified Tesla structures.

PubMed

Hong, Chien-Chong; Choi, Jin-Woo; Ahn, Chong H

2004-04-01

An innovative in-plane passive micromixer using modified Tesla structures, which are used as passive valves, has been designed, simulated, fabricated and successfully characterized in this paper. Simulation and experimental results of the developed novel micromixer have shown excellent mixing performance over a wide range of flow conditions in the micro scale. The micromixer realized in this work has achieved even better mixing performance at a higher flow rate, and its pressure drop is less than 10 KPa at the flow rate of 100 microl min(-1). This micromixer shows characteristics similar to Taylor dispersion, with contributions from both diffusion and convection. The mixer has a diffusion domain region at low flow rate, but it moves to a convection domain region at high flow rate. Due to the simple in-plane structure of the novel micromixer explored in this work, the mixer can be easily realized and integrated with on-chip microfluidic devices and micro total analysis systems (micro-TAS).

A 380 GHz SIS receiver using Nb/AlO(x)/Nb junctions for a radioastronomical balloon-borne experiment: PRONAOS

NASA Technical Reports Server (NTRS)

Febvre, P.; Feautrier, P.; Robert, C.; Pernot, J. C.; Germont, A.; Hanus, M.; Maoli, R.; Gheudin, M.; Beaudin, G.; Encrenaz, P.

1992-01-01

The superheterodyne detection technique used for the spectrometer instrument of the PRONAOS project will provide a very high spectral resolution (delta nu/nu = 10(exp -6)). The most critical components are those located at the front-end of the receiver: their contribution dominates the total noise of the receiver. Therefore, it is important to perform accurate studies for specific components, such as mixers and multipliers working in the submillimeter wave range. Difficulties in generating enough local oscillator (LO) power at high frequencies make SIS mixers very desirable for operation above 300 GHz. The low LO power requirements and the low noise temperature of these mixers are the primary reason for building an SIS receiver. This paper reports the successful fabrication of small (less than or equal to 1 sq micron) Nb/Al-O(x)/Nb junctions and arrays with excellent I-V characteristics and very good reliability, resulting in a low noise receiver performance measured in the 368/380 GHz frequency range.

Reconfigurable Control Design for the Full X-33 Flight Envelope

NASA Technical Reports Server (NTRS)

Cotting, M. Christopher; Burken, John J.

2001-01-01

A reconfigurable control law for the full X-33 flight envelope has been designed to accommodate a failed control surface and redistribute the control effort among the remaining working surfaces to retain satisfactory stability and performance. An offline nonlinear constrained optimization approach has been used for the X-33 reconfigurable control design method. Using a nonlinear, six-degree-of-freedom simulation, three example failures are evaluated: ascent with a left body flap jammed at maximum deflection; entry with a right inboard elevon jammed at maximum deflection; and landing with a left rudder jammed at maximum deflection. Failure detection and identification are accomplished in the actuator controller. Failure response comparisons between the nominal control mixer and the reconfigurable control subsystem (mixer) show the benefits of reconfiguration. Single aerosurface jamming failures are considered. The cases evaluated are representative of the study conducted to prove the adequate and safe performance of the reconfigurable control mixer throughout the full flight envelope. The X-33 flight control system incorporates reconfigurable flight control in the existing baseline system.

Review of mixer design for low voltage - low power applications

NASA Astrophysics Data System (ADS)

Nurulain, D.; Musa, F. A. S.; Isa, M. Mohamad; Ahmad, N.; Kasjoo, S. R.

2017-09-01

A mixer is used in almost all radio frequency (RF) or microwave systems for frequency translation. Nowadays, the increase market demand encouraged the industry to deliver circuit designs to create proficient and convenient equipment with very low power (LP) consumption and low voltage (LV) supply in both digital and analogue circuits. This paper focused on different Complementary Metal Oxide Semiconductor (CMOS) design topologies for LV and LP mixer design. Floating Gate Metal Oxide Semiconductor (FGMOS) is an alternative technology to replace CMOS due to their high ability for LV and LP applications. FGMOS only required a few transistors per gate and can have a shift in threshold voltage (VTH) to increase the LP and LV performances as compared to CMOS, which makes an attractive option to replace CMOS.

Development of SIS Mixers for 1 THz

NASA Technical Reports Server (NTRS)

Zmuidzinas, J.; Kooi, J.; Chattopadhyay, G.; Bumble, B.; LeDuc, H. G.; Stern, J. A.

1998-01-01

SIS heterodyne mixer technology based on niobium tunnel junctions has now been pushed to frequencies over 1 THz, clearly demonstrating that the SIS junctions are capable of mixing at frequencies up to twice the energy gap frequency (4 Delta/h). However, the performance degrades rapidly above the gap frequency of niobium (2 Delta/h approx. 700 GHz) due to substantial ohmic losses in the on-chip tuning circuit. To solve this problem, the tuning circuit should be fabricated using a superconducting film with a larger energy gap, such as NbN; unfortunately, NbN films often have a substantial excess surface resistance in the submillimeter band. In contrast, the SIS mixer measurements we present in this paper indicate that the losses for NbTiN thin films can be quite low.

Lobed Mixer Optimization for Advanced Ejector Geometries

NASA Technical Reports Server (NTRS)

Waitz, Ian A.

1996-01-01

The overall objectives are: 1) to pursue analytical, computational, and experimental studies that enhance basic understanding of forced mixing phenomena relevant to supersonic jet noise reduction, and 2) to integrate this enhanced understanding (analytical, computational, and empirical) into a design-oriented model of a mixer-ejector noise suppression system. The work is focused on ejector geometries and flow conditions typical of those being investigated in the NASA High Speed Research Program (HSRP). The research will be carried out in collaboration with the NASA HSRP Nozzle Integrated Technology Development (ITD) Team, and will both contribute to, and benefit from, the results of other HSRP research. The noise suppressor system model that is being developed under this grant is distinct from analytical tools developed by industry because it directly links details of lobe geometry to mixer-ejector performance. In addition, the model provides a 'technology road map to define gaps in the current understanding of various phenomena related to mixer-ejector design and to help prioritize research areas. This report describes research completed in the past year, as well as work proposed for the following year.

Very High Current Density Nb/AlN/Nb Tunnel Junctions for Low-Noise Submillimeter Mixers

NASA Technical Reports Server (NTRS)

Kawamura, Jonathan; Miller, David; Chen, Jian; Zmuidzinas, Jonas; Bumble, Bruce; LeDuc, Henry G.; Stern, Jeff A.

2000-01-01

We have fabricated and tested submillimeter-wave superconductor-insulator-superconductor (SIS) mixers using very high current density Nb/AlN/Nb tunnel junctions (J(sub c) approximately equal 30 kA/sq cm) . The junctions have low resistance-area products (R(sub N)A approximately 5.6 Omega.sq micron), good subgap to normal resistance ratios R(sub sg)/R(sub N) approximately equal 10, and good run-to-run reproducibility. From Fourier transform spectrometer measurements, we infer that omega.R(sub N)C = 1 at 270 GHz. This is a factor of 2.5 improvement over what is generally available with Nb/AlO(x)/Nb junctions suitable for low-noise mixers. The AlN-barrier junctions are indeed capable of low-noise operation: we measure an uncorrected receiver noise temperature of T(sub RX) = 110 K (DSB) at 533 GHz for an unoptimized device. In addition to providing wider bandwidth operation at lower frequencies, the AlN-barrier junctions will considerably improve the performance of THz SIS mixers by reducing RF loss in the tuning circuits.

Design of Interactively Time-Pulsed Microfluidic Mixers in Microchips using Numerical Simulation

NASA Astrophysics Data System (ADS)

Fu, Lung-Ming; Tsai, Chien-Hsiung

2007-01-01

In this paper, we propose a novel technique in which driving voltages are applied interactively to the respective inlet fluid flows of three configurations of a microfluidic device, namely T-shaped, double-T-shaped, and double-cross-shaped configurations, to induce electroosmotic flow (EOF) velocity variations in such a way as to develop a rapid mixing effect in the microchannel. In these configurations a microfluidic mixer apply only one electrokinetic driving force, which drives the sample fluids and simultaneously produces a periodic switching frequency. It requires no other external driving force to induce perturbations to the flow field. The effects of the main applied electric field, the interactive frequency, and the pullback electric field on the mixing performance are thoroughly examined numerically. The optimal interactive frequency range for a given set of micromixer parameters is identified for each type of control mode. The numerical results confirm that micromixers operating at an optimal interactive frequency are capable of delivering a significantly enhanced mixing performance. Furthermore, it is shown that the optimal interactive frequency depends upon the magnitude of the main applied electric field. The interactively pulsed mixers developed in this study have a strong potential for use in lab-on-a-chip systems. They involve a simpler fabrication process than either passive or active on-chip mixers and require less human intervention in operation than their bulky external counterparts.

Development of a Crush and Mix Machine for Composite Brick Fabrication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sothea, Kruy; Fazli, Nik; Hamdi, M.

2011-01-17

Currently, people are more and more concerned about the environmental protection. Municipal solid wastes (MSW) have bad effect on the environment and also human health. In addition, the amounts of municipal solid wastes are increasing due to the economic development, density of population, especially in the developing countries and they are recycled in a little percentage. To address this problem, the composite brick forming machine was designed and developed to make brick using combination of MSW and mortar. The machine consists of two independent parts, crusher and mixer part, and molding part. This paper explores the design of crusher andmore » mixer part. The crusher has ability to cut MSW such as wood, paper and plastic into small size. There are two mixers; one is used for making mortar and other use for making slurry. FEA analyses were carried out to address the suitable strength of the critical parts of the crusher which ensures that crusher can run properly with high efficiency. The experimentation of the crusher shows that it has high performance for cutting MSW. The mixers also work very well in high efficiency. The results of composite brick testing have been shown that ability of the machine can performance well. This is the innovation of crush and mix machine which is portable and economic by using MSW in replacement of sand.« less

Development of a Crush and Mix Machine for Composite Brick Fabrication

NASA Astrophysics Data System (ADS)

Sothea, Kruy; Fazli, Nik; Hamdi, M.; Aoyama, Hideki

2011-01-01

Currently, people are more and more concerned about the environmental protection. Municipal solid wastes (MSW) have bad effect on the environment and also human health. In addition, the amounts of municipal solid wastes are increasing due to the economic development, density of population, especially in the developing countries and they are recycled in a little percentage. To address this problem, the composite brick forming machine was designed and developed to make brick using combination of MSW and mortar. The machine consists of two independent parts, crusher and mixer part, and molding part. This paper explores the design of crusher and mixer part. The crusher has ability to cut MSW such as wood, paper and plastic into small size. There are two mixers; one is used for making mortar and other use for making slurry. FEA analyses were carried out to address the suitable strength of the critical parts of the crusher which ensures that crusher can run properly with high efficiency. The experimentation of the crusher shows that it has high performance for cutting MSW. The mixers also work very well in high efficiency. The results of composite brick testing have been shown that ability of the machine can performance well. This is the innovation of crush and mix machine which is portable and economic by using MSW in replacement of sand.

ATimer-Actuated, Immunoassay Cassette for Detecting Molecular Markers in Oral Fluids

PubMed Central

Liu, Changchun; Qiu, Xianbo; Ongagna, Serge; Chen, Dafeng; Chen, Zongyuan; Abrams, William R.; Malamud, Daniel; Corstjens, Paul L.A.M.; Bau, Haim H.

2009-01-01

An inexpensive, hand-held, point-of-care, disposable, self-contained, immunoassay cassette comprised of air pouches for pumping, a metering chamber, reagents storage chambers, a mixer, and a lateral flow strip was designed, constructed, and tested. The assay was carried out in a consecutive flow format. The detection was facilitated with up-converting, phosphor (UCP) reporter particles. The automated, timely pumping of the various reagents was driven by a spring-loaded timer. The utility of the cassette was demonstrated by detecting antibodies to HIV in saliva samples and further evaluated with a non-contagious, haptenized DNA assay. The cassette has several advantages over dip sticks such as sample preprocessing, integrated storage of reagents, and automated operation that reduces operator errors and training. The cassette and actuator described herein can readily be extended to detect biomarkers of other diseases in body fluids and other fluids at the point of care. The system is particularly suitable for resource poor countries, where funds and trained personnel are in short supply. PMID:19255658

Mixing in microfluidic devices and enhancement methods

PubMed Central

Ward, Kevin; Fan, Z Hugh

2015-01-01

Mixing in microfluidic devices presents a challenge due to laminar flows in microchannels, which result from low Reynolds numbers determined by the channel’s hydraulic diameter, flow velocity, and solution’s kinetic viscosity. To address this challenge, novel methods of mixing enhancement within microfluidic devices have been explored for a variety of applications. Passive mixing methods have been created, including those using ridges or slanted wells within the microchannels, as well as their variations with improved performance by varying geometry and patterns, by changing the properties of channel surfaces, and by optimization via simulations. In addition, active mixing methods including microstirrers, acoustic mixers, and flow pulsation have been investigated and integrated into microfluidic devices to enhance mixing in a more controllable manner. In general, passive mixers are easy to integrate, but difficult to control externally by users after fabrication. Active mixers usually take efforts to integrate within a device and they require external components (e.g. power sources) to operate. However, they can be controlled by users to a certain degree for tuned mixing. In this article, we provide a general overview of a number of passive and active mixers, discuss their advantages and disadvantages, and make suggestions on choosing a mixing method for a specific need as well as advocate possible integration of key elements of passive and active mixers to harness the advantages of both types. PMID:26549938

A "twisted" microfluidic mixer suitable for a wide range of flow rate applications.

PubMed

Sivashankar, Shilpa; Agambayev, Sumeyra; Mashraei, Yousof; Li, Er Qiang; Thoroddsen, Sigurdur T; Salama, Khaled Nabil

2016-05-01

This paper proposes a new "twisted" 3D microfluidic mixer fabricated by a laser writing/microfabrication technique. Effective and efficient mixing using the twisted micromixers can be obtained by combining two general chaotic mixing mechanisms: splitting/recombining and chaotic advection. The lamination of mixer units provides the splitting and recombination mechanism when the quadrant of circles is arranged in a two-layered serial arrangement of mixing units. The overall 3D path of the microchannel introduces the advection. An experimental investigation using chemical solutions revealed that these novel 3D passive microfluidic mixers were stable and could be operated at a wide range of flow rates. This micromixer finds application in the manipulation of tiny volumes of liquids that are crucial in diagnostics. The mixing performance was evaluated by dye visualization, and using a pH test that determined the chemical reaction of the solutions. A comparison of the tornado-mixer with this twisted micromixer was made to evaluate the efficiency of mixing. The efficiency of mixing was calculated within the channel by acquiring intensities using ImageJ software. Results suggested that efficient mixing can be obtained when more than 3 units were consecutively placed. The geometry of the device, which has a length of 30 mm, enables the device to be integrated with micro total analysis systems and other lab-on-chip devices.

A “twisted” microfluidic mixer suitable for a wide range of flow rate applications

PubMed Central

Sivashankar, Shilpa; Agambayev, Sumeyra; Mashraei, Yousof; Li, Er Qiang; Thoroddsen, Sigurdur T.; Salama, Khaled Nabil

2016-01-01

This paper proposes a new “twisted” 3D microfluidic mixer fabricated by a laser writing/microfabrication technique. Effective and efficient mixing using the twisted micromixers can be obtained by combining two general chaotic mixing mechanisms: splitting/recombining and chaotic advection. The lamination of mixer units provides the splitting and recombination mechanism when the quadrant of circles is arranged in a two-layered serial arrangement of mixing units. The overall 3D path of the microchannel introduces the advection. An experimental investigation using chemical solutions revealed that these novel 3D passive microfluidic mixers were stable and could be operated at a wide range of flow rates. This micromixer finds application in the manipulation of tiny volumes of liquids that are crucial in diagnostics. The mixing performance was evaluated by dye visualization, and using a pH test that determined the chemical reaction of the solutions. A comparison of the tornado-mixer with this twisted micromixer was made to evaluate the efficiency of mixing. The efficiency of mixing was calculated within the channel by acquiring intensities using ImageJ software. Results suggested that efficient mixing can be obtained when more than 3 units were consecutively placed. The geometry of the device, which has a length of 30 mm, enables the device to be integrated with micro total analysis systems and other lab-on-chip devices. PMID:27453767

Mixing in microfluidic devices and enhancement methods.

PubMed

Ward, Kevin; Fan, Z Hugh

2015-09-01

Mixing in microfluidic devices presents a challenge due to laminar flows in microchannels, which result from low Reynolds numbers determined by the channel's hydraulic diameter, flow velocity, and solution's kinetic viscosity. To address this challenge, novel methods of mixing enhancement within microfluidic devices have been explored for a variety of applications. Passive mixing methods have been created, including those using ridges or slanted wells within the microchannels, as well as their variations with improved performance by varying geometry and patterns, by changing the properties of channel surfaces, and by optimization via simulations. In addition, active mixing methods including microstirrers, acoustic mixers, and flow pulsation have been investigated and integrated into microfluidic devices to enhance mixing in a more controllable manner. In general, passive mixers are easy to integrate, but difficult to control externally by users after fabrication. Active mixers usually take efforts to integrate within a device and they require external components (e.g. power sources) to operate. However, they can be controlled by users to a certain degree for tuned mixing. In this article, we provide a general overview of a number of passive and active mixers, discuss their advantages and disadvantages, and make suggestions on choosing a mixing method for a specific need as well as advocate possible integration of key elements of passive and active mixers to harness the advantages of both types.

Static Mixer for Heat Transfer Enhancement for Mold Cooling Application

NASA Astrophysics Data System (ADS)

Becerra, Rodolfo; Barbosa, Raul; Lee, Kye-Hwan; Park, Younggil

Injection molding is the process by which a material is melted in a barrel and then it is injected through a nozzle in the mold cavity. When it cools down, the material solidifies into the shape of the cavity. Typical injection mold has cooling channels to maintain constant mold temperature during injection molding process. Even and constant temperature throughout the mold are very critical for a part quality and productivity. Conformal cooling improves the quality and productivity of injection molding process through the implementation of cooling channels that ``conform'' to the shape of the molded part. Recent years, the use of conformal cooling increases with advance of 3D printing technology such as Selective Laser Melting (SLM). Although it maximizes cooling, material and dimension limitations make SLM methods highly expensive. An alternative is the addition of static mixers in the molds with integrated cooling channels. A static mixer is a motionless mixing device that enhances heat transfer by producing improved flow mixing in the pipeline. In this study, the performance of the cooling channels will be evaluated with and without static mixers, by measuring temperature, pressure drop, and flow rate. The following question is addressed: Can a static mixer effectively enhance heat transfer for mold cooling application processes? This will provide insight on the development of design methods and guidelines that can be used to increase cooling efficiency at a lower cost.

Safety in ready mixed concrete industry: descriptive analysis of injuries and development of preventive measures.

PubMed

Akboğa, Özge; Baradan, Selim

2017-02-07

Ready mixed concrete (RMC) industry, one of the barebones of construction sector, has its distinctive occupational safety and health (OSH) risks. Employees experience risks that emerge during the fabrication of concrete, as well as its delivery to the construction site. Statistics show that usage and demand of RMC have been increasing along with the number of producers and workers. Unfortunately, adequate OSH measures to meet this rapid growth are not in place even in top RMC producing countries, such as Turkey. Moreover, lack of statistical data and academic research in this sector exacerbates this problem. This study aims to fill this gap by conducting data mining in Turkish Social Security Institution archives and performing univariate frequency and cross tabulation analysis on 71 incidents that RMC truck drivers were involved. Also, investigations and interviews were conducted in seven RMC plants in Turkey and Netherlands with OSH point of view. Based on the results of this research, problem areas were determined such as; cleaning truck mixer/pump is a hazardous activity where operators get injured frequently, and struck by falling objects is a major hazard at RMC industry. Finally, Job Safety Analyses were performed on these areas to suggest mitigation methods.

A Low-noise Micromachined Millimeter-Wave Heterodyne Mixer using Nb Superconducting Tunnel Junctions

NASA Technical Reports Server (NTRS)

DeLange, Gert; Jacobson, Brian R.; Hu, Qing

1996-01-01

A heterodyne mixer with a micromachined horn antenna and a superconductor-insulator-superconductor (SIS) tunnel junction as mixing element is tested in the W-band (75-115 GHz) frequency range. Micromachined integrated horn antennas consist of a dipole antenna suspended on a thin Si3N4 dielectric membrane inside a pyramidal cavity etched in silicon. The mixer performance is optimized by using a backing plane behind the dipole antenna to tune out the capacitance of the tunnel junction. The lowest receiver noise temperature of 30 +/- 3 K (without any correction) is measured at 106 GHz with a 3-dB bandwidth of 8 GHz. This sensitivity is comparable to the state-of-the-art waveguide and quasi-optical SIS receivers, showing the potential use of micromachined horn antennas in imaging arrays.

Optimization of integrated impeller mixer via radiotracer experiments.

PubMed

Othman, N; Kamarudin, S K; Takriff, M S; Rosli, M I; Engku Chik, E M F; Adnan, M A K

2014-01-01

Radiotracer experiments are carried out in order to determine the mean residence time (MRT) as well as percentage of dead zone, V dead (%), in an integrated mixer consisting of Rushton and pitched blade turbine (PBT). Conventionally, optimization was performed by varying one parameter and others were held constant (OFAT) which lead to enormous number of experiments. Thus, in this study, a 4-factor 3-level Taguchi L9 orthogonal array was introduced to obtain an accurate optimization of mixing efficiency with minimal number of experiments. This paper describes the optimal conditions of four process parameters, namely, impeller speed, impeller clearance, type of impeller, and sampling time, in obtaining MRT and V dead (%) using radiotracer experiments. The optimum conditions for the experiments were 100 rpm impeller speed, 50 mm impeller clearance, Type A mixer, and 900 s sampling time to reach optimization.

Terahertz radiation mixer

DOEpatents

Wanke, Michael C [Albuquerque, NM; Allen, S James [Santa Barbara, CA; Lee, Mark [Albuquerque, NM

2008-05-20

A terahertz radiation mixer comprises a heterodyned field-effect transistor (FET) having a high electron mobility heterostructure that provides a gatable two-dimensional electron gas in the channel region of the FET. The mixer can operate in either a broadband pinch-off mode or a narrowband resonant plasmon mode by changing a grating gate bias of the FET. The mixer can beat an RF signal frequency against a local oscillator frequency to generate an intermediate frequency difference signal in the microwave region. The mixer can have a low local oscillator power requirement and a large intermediate frequency bandwidth. The terahertz radiation mixer is particularly useful for terahertz applications requiring high resolution.

Diurnal variation in peak expiratory flow rate among polyvinylchloride compounding workers.

PubMed Central

Lee, H S; Ng, T P; Ng, Y L; Phoon, W H

1991-01-01

The diurnal variation in peak expiratory flow rate (PEFR) was studied in 24 mixers and 24 non-mixers in three polyvinylchloride (PVC) compounding plants and 24 non-PVC controls from a marine police workshop. The three groups (all men) were matched for age, race, and smoking. The mean respirable dust concentration (essentially PVC dust) was 1.6 mg/m3 for mixers and 0.4 mg/m3 for nonmixers. The mean diurnal variation in PEFR of the mixers was 6.5%. This was significantly higher than the 4.8% for non-mixers and 4.3% for the non-PVC controls. Six mixers had a diurnal variation of more than 15% on at least one day compared with none among the other two groups. Twenty nine per cent of mixers complained of wheezing compared with 4% of non-mixers and none among non-PVC workers. These differences were significant. Forced expiratory volume in one second (FEV1) for the mixers was 10% below the predicted values whereas that of non-PVC workers was 2% below predicted values. The study indicates a significant acute airway constriction from occupational exposure to PVC dust. PMID:2025595

Reduced T(sub c) Niobium Superconducting HEB Mixers

NASA Technical Reports Server (NTRS)

Siddiqi, I.; Prober, D. E.; Bumble, B.; LeDuc, H. G.

2001-01-01

A reduction in the mixer noise is expected when using superconductors with a lower transition temperature (T(sub c)) since the thermal noise components of the mixer noise should scale with T(sub c). Also, the local oscillator (LO) power required for a diffusion-cooled device should decrease as T(sub c) when T(sub bath) << T(sub c). We previously studied mixing in aluminum based hot-electron bolometers (HEBs) at microwave frequencies (approximately 30 GHz), and observed a significant improvement in noise performance, and a reduction in LO power as predicted. However, the bias voltage range over which good mixer performance was observed was approximately 5 - 10 microV. These devices are thus susceptible to saturation effects, in particular output saturation. In the present work, we have investigated Nb HEBs whose T(sub c) is lowered by applying a magnetic field. The goal is to study a case intermediate between Nb and Al, and hopefully to find properties that will allow use in practical receivers. A 15 kOe perpendicular magnetic field was applied to a Nb HEB (L = 0.16 micrometers, W = 0.08 micrometers, R(sub N) = 90 ohms) to reduce T(sub c) from 5.2 K to 2.4 K. The mixer noise, as inferred from the output noise and the conversion efficiency, decreased from 390 K, DSB to 171 K, DSB. The LO power required for near optimum mixer conversion efficiency (eta(sub mixer) = -9 dB in this device) was 8 nW in zero field, and approximately 2 nW when T(sub c) was reduced to 2.4 K. T(sub bath) = 0.22 K. The conversion bandwidth was previously measured to be 2.4 GHz and the same bandwidth was observed in the presence of a magnetic field. By lowering T(sub c), the voltage range over which good mixing was observed also decreased. However, even with T(sub c) reduced to 2.4 K, the conversion efficiency dropped by 3 dB from its maximum value only when the bias voltage was changed by approximately 90 microV. Saturation effects should thus be much less of a concern in these devices than in Al HEBS. In situations where the application of a large magnetic field is not feasible, we suggest using Ta based HEBS. Ta HEBs should have T(sub c) = 3 - 3.5 K and material properties very similar to Nb.

Low-noise submillimeter-wave NbTiN superconducting tunnel junction mixers

NASA Astrophysics Data System (ADS)

Kawamura, Jonathan; Chen, Jian; Miller, David; Kooi, Jacob; Zmuidzinas, Jonas; Bumble, Bruce; LeDuc, Henry G.; Stern, Jeff A.

1999-12-01

We have developed a low-noise 850 GHz superconductor-insulator-superconductor quasiparticle mixer with NbTiN thin-film microstrip tuning circuits and hybrid Nb/AlN/NbTiN tunnel junctions. The mixer uses a quasioptical configuration with a planar twin-slot antenna feeding a two-junction tuning circuit. At 798 GHz, we measured an uncorrected double-sideband receiver noise temperature of TRX=260 K at 4.2 K bath temperature. This mixer outperforms current Nb SIS mixers by a factor of nearly 2 near 800 GHz. The high-gap frequency and low loss at 800 GHz make NbTiN an attractive material with which to fabricate tuning circuits for SIS mixers. NbTiN mixers can potentially operate up to the gap frequency, 2Δ/h˜1.2 THz.

Low-Noise Submillimeter-Wave NbTiN Superconducting Tunnel Junction Mixers

NASA Technical Reports Server (NTRS)

Kawamura, J.; Chen, J.; Miller, D.; Kooi, J.; Zmuidzinas, J.; Bumble, B.; LeDuc, H. G.; Stern, J. A.

1999-01-01

We have developed a low-noise 850 GHz superconductor-insulator-superconductor (SIS) quasi-particle mixer with NbTiN thin-film microstrip tuning circuits and hybrid Nb/AlN/NbTiN tunnel junctions. The mixer uses a quasioptical configuration with a planar twin-slot antenna feeding a two-junction tuning circuit. At 798 GHz, we measured an uncorrected double-sideband receiver noise temperature of T(sub RX) = 260 K at 4.2 K bath temperature. This mixer outperforms current Nb SIS mixers by a factor of nearly 2 near 800 GHz. The high gap frequency and low loss at 800 GHz make NbTiN an attractive material with which to fabricate tuning circuits for SIS mixers. NbTiN mixers can potentially operate up to the gap frequency, 2(delta)/h is approximately 1.2THz.

Submillimeter heterodyne detection of interstellar carbon monoxide at 434 micrometers

NASA Technical Reports Server (NTRS)

Fetterman, H. R.; Clifton, B. J.; Peck, D. D.; Tannenwald, P. E.; Koepf, G. A.; Goldsmith, P. F.; Erickson, N. R.; Buhl, D.; Mcavoy, N.

1981-01-01

Laser heterodyne observations of submillimeter emissions from carbon monoxide in the Orion molecular cloud are reported. High frequency and spatial resolution observations were made at the NASA Infrared Telescope Facility on Mauna Kea by the use of an optically pumped laser local oscillator and quasi-optical Schottky diode mixer for heterodyne detection of the J = 6 - 5 rotational transition of CO at 434 microns. Spectral analysis of the 434-micron emission indicates that the emitting gas is optically thin and is at a temperature above 180 K. Results thus demonstrate the potential contributions of ground-based high-resolution submillimeter astronomy to the study of active regions in interstellar molecular clouds.

Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dan Golomb; Eugene Barry; David Ryan

2006-04-01

This semi-annual progress reports includes further findings on CO{sub 2}-in-Water emulsions stabilized by fine particles of limestone (CaCO{sub 3}). Specifically, here we report on the tests performed in the DOE National Energy Technology Laboratory High Pressure Water Tunnel Facility (HPWTF) using a Kenics-type static mixer for the formation of a CO{sub 2}-H{sub 2}O emulsion stabilized by fine particles of CaCO{sub 3}. The tested static mixer has an ID of 0.5 cm, length 23.5 cm, number of baffles 27. Under pressure, a slurry of CaCO{sub 3} particles (mean particle size 6 {micro}m) in reverse osmosis (RO) water and liquid CO{sub 2}more » were co-injected into the mixer. From the mixer, the resulting emulsion flowed into the HPWTF, which was filled with RO water kept at 6.8 MPa pressure and 4, 8 or 12 C. The emulsion plume was photographed by three video cameras through spy windows mounted on the wall of the HPWTF. The mixer produced an emulsion consisting of tiny CO{sub 2} droplets sheathed with a layer of CaCO{sub 3} particles dispersed in water. The sheathed droplets are called globules. The globules diameter was measured to be in the 300-500 {micro}m range. The globules were sinking in the HPWTF, indicating that they are heavier than the ambient water. The tests in the HPWTF confirmed that the Kenics-type static mixer is an efficient device for forming a CO{sub 2}-H{sub 2}O emulsion stabilized by fine particles of CaCO{sub 3}. The static mixer may prove to be a practical device for sequestering large quantities of CO{sub 2} in the deep ocean in the form of a CO{sub 2}-H{sub 2}O-CaCO{sub 3} emulsion. The static mixer can be mounted at the end of pipelines feeding the mixer. The static mixer has no moving parts. The pressure drop across the mixer that is necessary to sustain good mixing is created by the hydrostatic pressure of liquid CO{sub 2} and the slurry of CaCO{sub 3} in the pipes that feed the mixer. The tests in the HPWTF demonstrated that the emulsion plume is heavier than ambient seawater, hence the plume will sink to greater depth from the release point. Preliminary modeling indicates that an emulsion plume released at 500 m depth (the minimum depth required to prevent liquid CO{sub 2} flashing into vapor) may sink hundreds of meters before the plume comes to rest in the density stratified ocean water. Furthermore, tests in our laboratory showed that the emulsion is slightly alkaline, not acidic, because of the excess of CaCO{sub 3} particles present in the plume. Thus, the release of the CO{sub 2}-H{sub 2}OCaCO{sub 3} emulsion in the deep ocean is not likely to acidify the seawater around the release point. The possible acidification of seawater is the major environmental hazard if pure liquid CO{sub 2} were released in the deep ocean.« less

Modeling interfacial area transport in multi-fluid systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yarbro, Stephen Lee

1996-11-01

Many typical chemical engineering operations are multi-fluid systems. They are carried out in distillation columns (vapor/liquid), liquid-liquid contactors (liquid/liquid) and other similar devices. An important parameter is interfacial area concentration, which determines the rate of interfluid heat, mass and momentum transfer and ultimately, the overall performance of the equipment. In many cases, the models for determining interfacial area concentration are empirical and can only describe the cases for which there is experimental data. In an effort to understand multiphase reactors and the mixing process better, a multi-fluid model has been developed as part of a research effort to calculate interfacialmore » area transport in several different types of in-line static mixers. For this work, the ensemble-averaged property conservation equations have been derived for each fluid and for the mixture. These equations were then combined to derive a transport equation for the interfacial area concentration. The final, one-dimensional model was compared to interfacial area concentration data from two sizes of Kenics in-line mixer, two sizes of concurrent jet and a Tee mixer. In all cases, the calculated and experimental data compared well with the highest scatter being with the Tee mixer comparison.« less

Optimization of SIS mixer elements

NASA Technical Reports Server (NTRS)

Mattauch, Robert J.

1985-01-01

Superconductor-Insulator-Superconductor (SIS) quantum mixers provide an approach to millimeter wave mixing - potentially offering conversion gain, a low local oscillator power demand, and potential mixer noise temperatures near the quantum limit. The development of a reliable fabrication technology for producing such high quality SIS devices for mixer applications in radio astronomy is the focus of the work.

Mixer Assembly for a Gas Turbine Engine

NASA Technical Reports Server (NTRS)

Smith, Lance L. (Inventor); Fotache, Catalin G. (Inventor); Dai, Zhongtao (Inventor); Cohen, Jeffrey M. (Inventor); Hautman, Donald J. (Inventor)

2015-01-01

A mixer assembly for a gas turbine engine is provided, including a main mixer with fuel injection holes located between at least one radial swirler and at least one axial swirler, wherein the fuel injected into the main mixer is atomized and dispersed by the air flowing through the radial swirler and the axial swirler.

Mixer Assembly for a Gas Turbine Engine

NASA Technical Reports Server (NTRS)

Dai, Zhongtao (Inventor); Cohen, Jeffrey M. (Inventor); Fotache, Catalin G. (Inventor); Hautman, Donald J. (Inventor); Smith, Lance L. (Inventor)

2018-01-01

A mixer assembly for a gas turbine engine is provided, including a main mixer with fuel injection holes located between at least one radial swirler and at least one axial swirler, wherein the fuel injected into the main mixer is atomized and dispersed by the air flowing through the radial swirler and the axial swirler.

7 CFR 58.228 - Dump hoppers, screens, mixers and conveyors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Dump hoppers, screens, mixers and conveyors. 58.228... Service 1 Equipment and Utensils § 58.228 Dump hoppers, screens, mixers and conveyors. The product contact surfaces of dump hoppers, screens, mixers and conveyors which are used in the process of transferring dry...

Credit BG. This view looks northwest (290°) in the mixer ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. This view looks northwest (290°) in the mixer room at the 30-gallon Baker-Perkins model 121/2 PVM mixer and its associated equipment. The hopper in the left background feeds ingredients to the mixing pot when the hopper is mounted on the mixer frame; the hoist overhead is used to mount the hopper. The mixing pot is in its lowered position beneath the mixer blades. The pot is normally raised and secured to the upper half of the mixer, and a vacuum is applied during mixing operations to prevent the entrainment of air bubbles in the mix. A second mixing pot appears in the right background, and a pot vacuum lid appears in the extreme right foreground. The equipment on the palette in the left foreground is not related to the mixer. Note the explosion-proof fluorescent lighting fixtures suspended from the ceiling. The floor has an electrically conductive coating to dissipate static electrical charges - Jet Propulsion Laboratory Edwards Facility, Mixer & Casting Building, Edwards Air Force Base, Boron, Kern County, CA

Ion Chromatography-on-a-chip for Water Quality Analysis

NASA Technical Reports Server (NTRS)

Kidd, R. D.; Noell, A.; Kazarians, G.; Aubrey, A. D.; Scianmarello, N.; Tai, Y.-C.

2015-01-01

We report progress towards developing a Micro-Electro-Mechanical Systems (MEMS)- based ion chromatograph (IC) for crewed spacecraft water analysis. This IC-chip is an offshoot of a NASA-funded effort to produce a high performance liquid chromatograph (HPLC)-chip. This HPLC-chip system would require a desalting (i.e. ion chromatography) step. The complete HPLC instrument consists of the Jet Propulsion Labortory's (JPL's) quadrupole ion trap mass spectrometer integrated with a state-of-the-art MEMS liquid chromatograph (LC) system developed by the California Institute of Technology's (Caltech's) Micromachining Laboratory. The IC version of the chip consist of an electrolysis-based injector, a separation column, two electrolysis pumps for gradient generation, mixer, and a built-in conductivity detector. The HPLC version of the chip also includes a nanospray tip. The low instrument mass, coupled with its high analytical capabilities, makes the LC chip ideally suitable for wide range of applications such as trace contaminant, inorganic analytical science and, when coupled to a mass spectrometer, a macromolecular detection system for either crewed space exploration vehicles or robotic planetary missions.

21 CFR 888.4210 - Cement mixer for clinical use.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement mixer for clinical use. 888.4210 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4210 Cement mixer for clinical use. (a) Identification. A cement mixer for clinical use is a device consisting of a container intended for use in mixing...

21 CFR 888.4210 - Cement mixer for clinical use.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cement mixer for clinical use. 888.4210 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4210 Cement mixer for clinical use. (a) Identification. A cement mixer for clinical use is a device consisting of a container intended for use in mixing...

21 CFR 888.4210 - Cement mixer for clinical use.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cement mixer for clinical use. 888.4210 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4210 Cement mixer for clinical use. (a) Identification. A cement mixer for clinical use is a device consisting of a container intended for use in mixing...

21 CFR 888.4210 - Cement mixer for clinical use.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cement mixer for clinical use. 888.4210 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4210 Cement mixer for clinical use. (a) Identification. A cement mixer for clinical use is a device consisting of a container intended for use in mixing...

21 CFR 888.4210 - Cement mixer for clinical use.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cement mixer for clinical use. 888.4210 Section... (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4210 Cement mixer for clinical use. (a) Identification. A cement mixer for clinical use is a device consisting of a container intended for use in mixing...

Conversion loss and noise of microwave and millimeter-wave mixers. I - Theory. II - Experiment

NASA Technical Reports Server (NTRS)

Held, D. N.; Kerr, A. R.

1978-01-01

The conversion loss and noise of microwave and millimeter-wave mixers are analyzed. Nonlinear capacitance, arbitrary embedding impedances, as well as shot, thermal and scattering noise arising in the diode, figure in the analysis. The anomalous mixer noise noted in millimeter-wave mixers by Kerr (1975) is shown to be explainable in terms of the correlation of down-converted components of the time-varying shot noise. A digital computer analysis of the conversion loss, noise, and output impedance of an 80-120-GHz mixer is also conducted.

11. VIEW OF HORIZONTAL MIXER (GedgeGray Co., Lockland, Ohio), LOCATED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. VIEW OF HORIZONTAL MIXER (Gedge-Gray Co., Lockland, Ohio), LOCATED IN THE BASEMENT, MIXED ANIMAL FEED TO ORDER. THE WATER-POWERED MIXER WAS SUPERSEDED BY TWO ELECTRIC-POWERED VERTICAL MIXERS, ADDED IN THE 1940S. Photographer: Louise Taft Cawood, July 1986 - Alexander's Grist Mill, Lock 37 on Ohio & Erie Canal, South of Cleveland, Valley View, Cuyahoga County, OH

A wideband current-commutating passive mixer for multi-standard receivers in a 0.18 μm CMOS

NASA Astrophysics Data System (ADS)

Kuan, Bao; Xiangning, Fan; Wei, Li; Zhigong, Wang

2013-01-01

This paper reports a wideband passive mixer for direct conversion multi-standard receivers. A brief comparison between current-commutating passive mixers and active mixers is presented. The effect of source and load impedance on the linearity of a mixer is analyzed. Specially, the impact of the input impedance of the transimpedance amplifier (TIA), which acts as the load impedance of a mixer, is investigated in detail. The analysis is verified by a passive mixer implemented with 0.18 μm CMOS technology. The circuit is inductorless and can operate over a broad frequency range. On wafer measurements show that, with radio frequency (RF) ranges from 700 MHz to 2.3 GHz, the mixer achieves 21 dB of conversion voltage gain with a -1 dB intermediate frequency (IF) bandwidth of 10 MHz. The measured IIP3 is 9 dBm and the measured double-sideband noise figure (NF) is 10.6 dB at 10 MHz output. The chip occupies an area of 0.19 mm2 and drains a current of 5.5 mA from a 1.8 V supply.

Acoustic characteristics of externally blown flap systems with mixer nozzles

NASA Technical Reports Server (NTRS)

Goodykoontz, J. H.; Dorsch, R. G.; Wagner, J. M.

1974-01-01

Noise tests were conducted on a large scale, cold flow model of an engine-under-the-wing externally blown flap lift augmentation system employing a mixer nozzle. The mixer nozzle was used to reduce the flap impingement velocity and, consequently, try to attenuate the additional noise caused by the interaction between the jet exhaust and the wing flap. Results from the mixer nozzle tests are summarized and compared with the results for a conical nozzle. The comparison showed that with the mixer nozzle, less noise was generated when the trailing flap was in a typical landing setting (e.g., 60 deg). However, for a takeoff flap setting (20 deg), there was little or no difference in the acoustic characteristics when either the mixer or conical nozzle was used.

Noise tests of a mixer nozzle-externally blown flap system

NASA Technical Reports Server (NTRS)

Goodykoontz, J. H.; Dorsch, R. G.; Groesbeck, D. E.

1973-01-01

Noise tests were conducted on a large scale model of an externally blown flap lift augmentation system, employing a mixer nozzle. The mixer nozzle consisted of seven flow passages with a total equivalent diameter of 40 centimeters. With the flaps in the 30 - 60 deg setting, the noise level below the wing was less with the mixer nozzle than when a standard circular nozzle was used. At the 10 - 20 deg flap setting, the noise levels were about the same when either nozzle was used. With retracted flaps, the noise level was higher when the mixer nozzle was used.

Submillimeter wave detection with superconducting tunnel diodes

NASA Technical Reports Server (NTRS)

Wengler, Michael J.

1992-01-01

Superconductor-Insulator-Superconductor (SIS) diodes are the detector elements in the most sensitive heterodyne receivers available from 100 to 500 GHz. SIS mixers are the front end of radio astronomical systems around the world. SIS mixer technology is being extended to 1 THz and higher frequencies for eventual use on spaceborne astronomical experiments. Here is a short review of submillimeter SIS mixers. The role of impedance matching in the proper design of an SIS mixer is described. A variety of methods for achieving good impedance match at submillimeter frequencies are presented. The experimental state of the submillimeter SIS mixer art is described and summarized.

Micro and nano devices in passive millimetre wave imaging systems

NASA Astrophysics Data System (ADS)

Appleby, R.

2013-06-01

The impact of micro and nano technology on millimetre wave imaging from the post war years to the present day is reviewed. In the 1950s whisker contacted diodes in mixers and vacuum tubes were used to realise both radiometers and radars but required considerable skill to realise the performance needed. Development of planar semiconductor devices such as Gunn and Schottky diodes revolutionised mixer performance and provided considerable improvement. The next major breakthrough was high frequency transistors based on gallium arsenide which were initially used at intermediate frequencies but later after further development at millimeter wave frequencies. More recently Monolithic Microwave Integrated circuits(MMICs) offer exceptional performance and the opportunity for innovative design in passive imaging systems. In the future the use of micro and nano technology will continue to drive system performance and we can expect to see integration of antennae, millimetre wave and sub millimetre wave circuits and signal processing.

26 CFR 48.4061-1 - Temporary regulations with respect to floor stock refunds or credits on cement mixers.

Code of Federal Regulations, 2012 CFR

2012-04-01

... stock refunds or credits on cement mixers. 48.4061-1 Section 48.4061-1 Internal Revenue INTERNAL REVENUE... § 48.4061-1 Temporary regulations with respect to floor stock refunds or credits on cement mixers. (a... of tax on motor vehicles) on the sale of a cement mixer after June 30, 1968, and before January 1...

26 CFR 48.4061-1 - Temporary regulations with respect to floor stock refunds or credits on cement mixers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... stock refunds or credits on cement mixers. 48.4061-1 Section 48.4061-1 Internal Revenue INTERNAL REVENUE... § 48.4061-1 Temporary regulations with respect to floor stock refunds or credits on cement mixers. (a... of tax on motor vehicles) on the sale of a cement mixer after June 30, 1968, and before January 1...

26 CFR 48.4061-1 - Temporary regulations with respect to floor stock refunds or credits on cement mixers.

Code of Federal Regulations, 2013 CFR

2013-04-01

... stock refunds or credits on cement mixers. 48.4061-1 Section 48.4061-1 Internal Revenue INTERNAL REVENUE... § 48.4061-1 Temporary regulations with respect to floor stock refunds or credits on cement mixers. (a... of tax on motor vehicles) on the sale of a cement mixer after June 30, 1968, and before January 1...

Alternative Fuels Data Center: Ozinga Adds 14 Natural Gas Concrete Mixers

Science.gov Websites

to Its Fleet Ozinga Adds 14 Natural Gas Concrete Mixers to Its Fleet to someone by E-mail Share Alternative Fuels Data Center: Ozinga Adds 14 Natural Gas Concrete Mixers to Its Fleet on Facebook Tweet about Alternative Fuels Data Center: Ozinga Adds 14 Natural Gas Concrete Mixers to Its Fleet on Twitter Bookmark

26 CFR 48.4061-1 - Temporary regulations with respect to floor stock refunds or credits on cement mixers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... stock refunds or credits on cement mixers. 48.4061-1 Section 48.4061-1 Internal Revenue INTERNAL REVENUE... § 48.4061-1 Temporary regulations with respect to floor stock refunds or credits on cement mixers. (a... of tax on motor vehicles) on the sale of a cement mixer after June 30, 1968, and before January 1...

Altitude test of several afterburner configurations on a turbofan engine with a hydrogen heater to simulate an elevated turbine discharge temperature

NASA Technical Reports Server (NTRS)

Johnsen, R. L.; Cullom, R. R.

1977-01-01

A performance test of several experimental afterburner configurations was conducted with a mixed-flow turbofan engine in an altitude facility. The simulated flight conditions were for Mach 1.4 at two altitudes, 12,190 and 14,630 meters. Turbine discharge temperatures of 889 and 1056 K were used. A production afterburner was tested for comparison. The research afterburners included partial forced mixers with V-gutter flameholders, a carburetted V-gutter flameholder, and a triple ring V-gutter flameholder with four swirl-can fuel mixers. Fuel injection variations were included. Performance data shown include augmented thrust ratio, thrust specific fuel consumption, combustion efficiency, and total pressure drop across the afterburner.

Full Navier-Stokes analysis of a two-dimensional mixer/ejector nozzle for noise suppression

NASA Technical Reports Server (NTRS)

Debonis, James R.

1992-01-01

A three-dimensional full Navier-Stokes (FNS) analysis was performed on a mixer/ejector nozzle designed to reduce the jet noise created at takeoff by a future supersonic transport. The PARC3D computational fluid dynamics (CFD) code was used to study the flow field of the nozzle. The grid that was used in the analysis consisted of approximately 900,000 node points contained in eight grid blocks. Two nozzle configurations were studied: a constant area mixing section and a diverging mixing section. Data are presented for predictions of pressure, velocity, and total temperature distributions and for evaluations of internal performance and mixing effectiveness. The analysis provided good insight into the behavior of the flow.

Low-Loss NbTiN Films for THz SIS Mixer Tuning Circuits

NASA Technical Reports Server (NTRS)

Kooi, J. W.; Stern, J. A.; Chattopadhyay, G.; LeDuc, H. G.; Bumble, B.; Zmuidzinas, J.

1998-01-01

Recent results at 1 THz using normal-metal tuning circuits have shown that SIS mixers can work well up to twice the gap frequency of the junction material (niobium). However, the performance at 1 THz is limited by the substantial loss in the normal metal films. For better performance superconducting films with a higher gap frequency than niobium and with low RF loss are needed. Niobium nitride has long been considered a good candidate material, but typical NbN films suffer from high RF loss. To circumvent this problem we are currently investigating the RF loss in NbTiN films, a 15 K Tc compound superconductor, by incorporating them into quasi-optical slot antenna SIS devices.

Broadly tunable picosecond ir source

DOEpatents

Campillo, A.J.; Hyer, R.C.; Shapiro, S.L.

1980-04-23

A picosecond traveling-wave parametric device capable of controlled spectral bandwidth and wavelength in the infrared is reported. Intense 1.064 ..mu..m picosecond pulses (1) pass through a 4.5 cm long LiNbO/sub 3/ optical parametric oscillator crystal (2) set at its degeneracy angle. A broad band emerges, and a simple grating (3) and mirror (4) arrangement is used to inject a selected narrow-band into a 2 cm long LiNbO/sub 3/ optical parametric amplifier crystal (5) along a second pump line. Typical input energies at 1.064 ..mu..m along both pump lines are 6 to 8 mJ for the oscillator and 10 mJ for the amplifier. This yields 1 mJ of tunable output in the range 1.98 to 2.38 ..mu..m which when down-converted in a 1 cm long CdSe crystal mixer (6) gives 2 ..mu..J of tunable radiation over the 14.8 to 18.5 ..mu..m region. The bandwidth and wavelength of both the 2 and 16 ..mu..m radiation output are controlled solely by the diffraction grating.

Use of Buckling Instabilities in Micro Pumps, Valves, and Mixers

NASA Astrophysics Data System (ADS)

Tavakol, Behrouz; Chawan, Aschvin; Holmes, Douglas

2014-03-01

We use the buckling of thin, flexible plates for pumping fluids, controlling the flow rate, and mixing different media within a microfluidic channel. A dielectric elastomeric film with a confined geometry buckles out of the plane when exposed to an electric field. Solid or grease electrodes have traditionally been used as conductive materials to aid in voltage application to both sides of the film. In this work, we use an electrolytic fluid solution as the electrode to enable buckling at relatively low voltages, and to enhance the rate of deformation. We show that this mechanism can be implemented as a microvalve that controls flow rate, or as a micropump that operates over a range of frequencies. A similar mechanism can be used to aid diffusion between two adjacent laminar streams and improve mixing. These low-cost micropumps, microvalves, and micromixers rely on the reversible buckling of thin plates, are easily embeddable in a microfluidic chip, and can potentially be used in variety of applications to accurately control and manipulate fluid flow in a microchannel.

Broadly tunable picosecond IR source

DOEpatents

Campillo, Anthony J.; Hyer, Ronald C.; Shapiro, Stanley J.

1982-01-01

A picosecond traveling-wave parametric device capable of controlled spectral bandwidth and wavelength in the infrared is reported. Intense 1.064 .mu.m picosecond pulses (1) pass through a 4.5 cm long LiNbO.sub.3 optical parametric oscillator crystal (2) set at its degeneracy angle. A broad band emerges, and a simple grating (3) and mirror (4) arrangement is used to inject a selected narrow-band into a 2 cm long LiNbO.sub.3 optical parametric amplifier crystal (5) along a second pump line. Typical input energies at 1.064 .mu.m along both pump lines are 6-8 mJ for the oscillator and 10 mJ for the amplifier. This yields 1 mJ of tunable output in the range 1.98 to 2.38 .mu.m which when down-converted in a 1 cm long CdSe crystal mixer (6) gives 2 .mu.J of tunable radiation over the 14.8 to 18.5 .mu.m region. The bandwidth and wavelength of both the 2 and 16 .mu.m radiation output are controlled solely by the diffraction grating.

Modelling and performance of Nb SIS mixers in the 1.3 mm and 0.8 mm bands

NASA Technical Reports Server (NTRS)

Karpov, A.; Carter, M.; Lazareff, B.; Billon-Pierron, D.; Gundlach, K. H.

1992-01-01

We describe the modeling and subsequent improvements of SIS waveguide mixers for the 200-270 and 330-370 GHz bands (Blundell, Carter, and Gundlach 1988, Carter et al 1991). These mixers are constructed for use in receivers on IRAM radiotelescopes on Pico Veleta (Spain, Sierra Nevada) and Plateau de Bure (French Alps), and must meet specific requirements. The standard reduced height waveguide structure with suspended stripline is first analyzed and a model is validated through comparison with scale model and working scale measurements. In the first step, the intrinsic limitations of the standard mixer structure are identified, and the parameters are optimized bearing in mind the radioastronomical applications. In the second step, inductive tuning of the junctions is introduced and optimized for minimum noise and maximum bandwidth. In the 1.3 mm band, a DSB receiver temperature of less than 110 K (minimum 80 K) is measured from 180 through 260 GHz. In the 0.8 mm band, a DSB receiver temperature of less than 250 K (minimum 175 K) is obtained between 325 and 355 GHz. All these results are obtained with room-temperature optics and a 4 GHz IF chain having a 500 MHz bandwidth and a noise temperature of 14 K.

Apparatus and method for suppressing sound in a gas turbine engine powerplant

NASA Technical Reports Server (NTRS)

Wynosky, Thomas A. (Inventor); Mischke, Robert J. (Inventor)

1992-01-01

A method and apparatus for suppressing jet noise in a gas turbine engine powerplant 10 is disclosed. Various construction details are developed for providing sound suppression at sea level take-off operative conditions and not providing sound suppression at cruise operative conditions. In one embodiment, the powerplant 10 has a lobed mixer 152 between a primary flowpath 44 and a second flowpath 46, a diffusion region downstream of the lobed mixer region (first mixing region 76), and a deployable ejector/mixer 176 in the diffusion region which forms a second mixing region 78 having a diffusion flowpath 72 downstream of the ejector/mixer and sound absorbing structure 18 bounding the flowpath throughout the diffusion region. The method includes deploying the ejector/mixer 176 at take-off and stowing the ejector/mixer at cruise.

Photothermal generation of microbubbles on plasmonic nanostructures inside microfluidic channels

NASA Astrophysics Data System (ADS)

Li, Jingting; Li, Ming; Santos, Greggy M.; Zhao, Fusheng; Shih, Wei-Chuan

2016-03-01

Microbubbles have been utilized as micro-pumps, micro-mixers, micro-valves, micro-robots and surface cleaners. Various generation techniques can be found in the literature, including resistive heating, hydrodynamic methods, illuminating patterned metal films and noble metal nanoparticles of Au or Ag. We present photothermal microbubble generation by irradiating nanoporous gold disk covered microfluidic channels. The size of the microbubble can be controlled by adjusting the laser power. The dynamics of both bubble growth and shrinkage are studied. The advantages of this technique are flexible bubble generation locations, long bubble lifetimes, no need for light-adsorbing dyes, high controllability over bubble size, low power consumption, etc. This technique has the potential to provide new flow control functions in microfluidic devices.

Credit BG. The southeast and northeast facades appear as seen ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. The southeast and northeast facades appear as seen when looking due west (270°). Doors to the mixer room are open; the smaller closed doors lead to a building equipment room containing heating and refrigeration units for temperature control of the mixer and its contents. The mixer room doors and sidewalls are filled with foam and constructed to blow out in case of an explosion in the mixer. Note the lightning rods and two exterior emergency showers. The two tanks at the eastern corner of the building are unidentified - Jet Propulsion Laboratory Edwards Facility, Mixer & Casting Building, Edwards Air Force Base, Boron, Kern County, CA

BIB mixers

NASA Technical Reports Server (NTRS)

1995-01-01

We have determined that the multi-pin 'microprocessor style' packages in which current Blocked Impurity Band (BIB) devices are mounted will not meet our IF bandwidth spec of greater than 2 GHz for a practical mixer. Hence we have started to repackage the Ga:Ge BIB devices in new microwave compatible packages. The smaller size of the microwave package mount necessitates cutting the BIB array down to include only the 3 smallest detectors: 0.2, 0.4, and 0.6 mm sq. A FIR beam incident at f/1.5 can be focussed on the smallest element for wavelengths shorter than 100 microns. A more typical (easier) beam convergence of f/3 will require 0.4 mm elements at 100 microns and 0.6 mm elements at 170 microns wavelength. Since the device capacitance (parasitic loss) scales with detector size, there is a tradeoff of speed of response and optical convenience. Our existing optics produce only the slower convergence beam, so we need to redesign the optical layout and are looking at long focal length all-reflective microscope objectives. BIB detectors and the edge-coupled microbolometers have restricted IF bandwidths, an order of magnitude less than what is possible with the Schottky-diode mixers we currently use for astronomical observations. Consequently the frequencies of the FIR laser lines must be close to the astronomical line of interest to be an effective Local Oscillator (LO). We have therefore begun a coordinated effort to discover and measure new FIR laser transition lines in close frequency coincidence with important astrophysical lines. Most of this effort involves pumping isotopic variants of known good laser molecules with laser lines from isotopic variants of CO2. We have been most successful in detecting new FIR lines in deuterated ammonia. One line in particular is very close to the frequency of HD rotational line at 2675 GHz.

Simulation and measurement of a Ka-band HTS MMIC Josephson junction mixer

NASA Astrophysics Data System (ADS)

Zhang, Ting; Pegrum, Colin; Du, Jia; Guo, Yingjie Jay

2017-01-01

We report modeling and simulation results for a Ka band high-temperature superconducting (HTS) monolithic microwave integrated circuit (MMIC) Josephson junction mixer. A Verilog-A model of a Josephson junction is established and imported into the system simulator to realize a full HTS MMIC circuit simulation containing the HTS passive circuit models. Impedance matching optimization between the junction and passive devices is investigated. Junction DC I-V characteristics, current and local oscillator bias conditions and mixing performance are simulated and compared with the experimental results. Good agreement is obtained between the simulation and measurement results.

Safety in ready mixed concrete industry: descriptive analysis of injuries and development of preventive measures

PubMed Central

AKBOĞA, Özge; BARADAN, Selim

2016-01-01

Ready mixed concrete (RMC) industry, one of the barebones of construction sector, has its distinctive occupational safety and health (OSH) risks. Employees experience risks that emerge during the fabrication of concrete, as well as its delivery to the construction site. Statistics show that usage and demand of RMC have been increasing along with the number of producers and workers. Unfortunately, adequate OSH measures to meet this rapid growth are not in place even in top RMC producing countries, such as Turkey. Moreover, lack of statistical data and academic research in this sector exacerbates this problem. This study aims to fill this gap by conducting data mining in Turkish Social Security Institution archives and performing univariate frequency and cross tabulation analysis on 71 incidents that RMC truck drivers were involved. Also, investigations and interviews were conducted in seven RMC plants in Turkey and Netherlands with OSH point of view. Based on the results of this research, problem areas were determined such as; cleaning truck mixer/pump is a hazardous activity where operators get injured frequently, and struck by falling objects is a major hazard at RMC industry. Finally, Job Safety Analyses were performed on these areas to suggest mitigation methods. PMID:27524105

Self-anchoring mast for deploying a high-speed submersible mixer in a tank

DOEpatents

Cato, Jr., Joseph E.; Shearer, Paul M [Aiken, SC; Rodwell, Philip O [Evans, GA

2004-10-12

A self-anchoring mast for deploying a high-speed submersible mixer in a tank includes operably connected first and second mast members (20, 22) and a foot member 46 operably connected to the second mast member for supporting the mast in a tank. The second mast member includes a track (36, 38) for slidably receiving a bearing of the mixer to change the orientation of the mixer in the tank.

Effect of zeta potential on the performance of a ring-type electroosmotic mixer.

PubMed

Kim, T A; Koo, K H; Kim, Y J

2009-12-01

In order to achieve faster mixing, a new type of electrokinetic mixer with a T-type channel is introduced. The proposed mixer takes two fluids from different inlets and combines them into a single channel. The fluids then enter a mixing chamber with different inner and outer radii. Four microelectrodes are positioned on the outer wall of the mixing chamber. The electric potentials on the four microelectrodes are sinusoidal with respect to time and have various maximum voltages, zeta potentials and frequency values. The working fluid is water and each inlet has a different initial concentration values. The incompressible Navier-Stokes equation is solved in the channel, with a slip boundary condition on the inner and outer walls of the mixing chamber. The convection-diffusion equation is used to describe the concentration of the dissolved substances in the fluid. The pressure, concentration and flow fields in the channel are calculated and the results are graphically depicted for various flow and electric conditions.

INTERIOR VIEW OF MIXER LOCATED ON SECOND FLOOR OF BATCH ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR VIEW OF MIXER LOCATED ON SECOND FLOOR OF BATCH PLANT. RECENTLY PURCHASED TO REPLACE OLD MIXER. USED TO MIX THE BATCH - Chambers-McKee Window Glass Company, Batch Plant, Clay Avenue Extension, Jeannette, Westmoreland County, PA

Dynamics of Crust Dissolution and Gas Release in Tank 241-SY-101

DOE Office of Scientific and Technical Information (OSTI.GOV)

SD Rassat; CW Stewart; BE Wells

2000-01-26

Due primarily to an increase in floating crust layer thickness, the waste level in Hanford Tank 241-SY-101 (SY-101) has grown appreciably, and the flammable gas volume stored in the crust has become a potential hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from the nonconnective layer at the bottom of the tank, SY-101 will be diluted to dissolve a large fraction of the solids that allow the waste to retain gas. In this work we develop understanding of the state of the tank waste and some of its physical properties, investigate howmore » added water will be distributed in the tank and affect the waste, and use the information to evaluate mechanisms and rates of waste solids dissolution and gas release. This work was completed to address these questions and in support of planning and development of controls for the SY-101 Surface Level Rise Remediation Project. Particular emphasis is given to dissolution of and gas release from the crust, although the effects of back-dilution on all waste layers are addressed. The magnitude and rates of plausible gas release scenarios are investigated, and it is demonstrated that none of the identified mechanisms of continuous (dissolution-driven) or sudden gas release, even with conservative assumptions, lead to domespace hydrogen concentrations exceeding the lower flammability limit. This report documents the results of studies performed in 1999 to address the issues of the dynamics, of crust dissolution and gas release in SY-101. It contains a brief introduction to the issues at hand; a summary of our knowledge of the SY-101 crust and other waste properties, including gas fractions, strength and volubility; a description of the buoyancy and dissolution models that are applied to predict the crust response to waste transfers and back dilution; and a discussion of the effectiveness of mixing for water added below the crust and the limited potential for significant stratification resulting from such additions. The effect of the mixer pump on stratified fluid layers below the crust, should they form, is also addressed. It is hypothesized that the crust may sink after the most gaseous portion near the base of the crust is dissolved and after the liquid layer below the crust is diluted sufficiently. Then we discuss the consequences of crust sinking in terms of gas release, the ability of the in-tank mixer pump to remobilize it, and the potential for recurrence of buoyant displacement gas release events.« less

Performance of a 2.5 THz Receiver Front-End for Spaceborne Applications

NASA Technical Reports Server (NTRS)

Gaidis, Michael C.; Pickett, H. M.; Siegel, P. H.; Smith, C. D.; Smith, R. P.; Martin, S. C.

1999-01-01

The OH radical plays a significant role in a great many of the known ozone destruction cycles, and has become the focus of an important radiometer development effort for NASA's Earth Observing System Chem I satellite, which will monitor and study many tropospheric and stratospheric gases and is scheduled for launch in 2002. Here we describe the design, fabrication, and testing of a receiver front end used to detect the OH signals at 2.5 THz. This is to be the first Terahertz heterodyne receiver to be flown in space. The challenges of producing the necessary high-performance mixers are numerous, but for this application, there is the added challenge of designing a robust receiver which can withstand the environmental extremes of a rocket launch and five years in space. The receiver front-end consists of the following components: a four-port dual-polarization diplexer, off-axis elliptical feed mirrors, mixers for horizontal and vertical polarization, support structures allowing simple and rugged alignment, low noise IF amplification from 7.7 to 21.1 GHz, and mixer DC bias circuitry. The front-end design, alignment, and operation will be covered in depth, followed by a discussion of the most recent results in receiver noise and dual-mode horn beam patterns. JPL MOMED mixers are employed, and have resulted in receiver noise temperatures of 14,500 K, DSB with LO frequency 2.522 GHz and IF of 12.8 GHz. Horn beam patterns correspond well with theory, with no significant sidelobes above the -25 dB level. Considering the high-quality beam of this receiver, these results are competitive with the best reported in the literature.

Negative Differential Resistance (NDR) frequency conversion with gain

NASA Technical Reports Server (NTRS)

Hwu, R. J.; Alm, R. W.; Lee, S. C.

1992-01-01

The dependence of the I-V characteristic of the negative differential resistance (NDR) devices on the power level and frequency of the rf input signal has been theoretically analyzed with a modified large- and small-signal nonlinear circuit analysis program. The NDR devices we used in this work include both the tunnel diode (without the antisymmetry in the I-V characteristic) and resonant-tunneling devices (with the antisymmetry in the I-V characteristic). Absolute negative conductance can be found from a zero-biased resonant tunneling device when the applied pump power is within a small range. This study verifies the work of Sollner et al. Variable negative conductances at the fundamental and harmonic frequencies can also be obtained from both the unbiased and biased tunnel diodes. The magnitude of the negative conductances can be adjusted by varying the pump amplitude -- a very useful circuit property. However, the voltage range over which the negative conductance occurs moves towards the more positive side of the voltage axis with increasing frequency. Furthermore, the range of the pumping amplitude to obtain negative conductance varies with the parasitics (resistance and capacitance) of the device. The theoretical observation of the dependence of the I-V characteristic of the NDR devices on the power and frequency of the applied pump signal is supported by the experimental results. In addition, novel functions of a NDR device such as self-oscillating frequency multiplier and mixer with gain have been experimentally demonstrated. The unbiased oscillator have also been successfully realized with a NDR device with an antisymmetrical I-V characteristic. Finally, the applications of these device functions will be discussed.

The effect of AM noise on correlation phase-noise measurements.

PubMed

Rubiola, Enrico; Boudot, Rodolphe

2007-05-01

We analyze the phase-noise measurement methods in which correlation and averaging is used to reject the background noise of the instrument. All the known methods make use of a mixer, used either as a saturated-phase detector or as a linear-synchronous detector. Unifortunately, AM noise is taken in through the power-to-dc-offset conversion mechanism that results from the mixer asymmetry. The measurement of some mixers indicates that the unwanted amplitude-to-voltage gain is of the order of 5-50 mV, which is 12-35 dB lower than the phase-to-voltage gain of the mixer. In addition, the trick of setting the mixer at a sweet point--off the quadrature condition--where the sensitivity to AM nulls, works only with microwave mixers. The HF-VHF mixers do not have this sweet point. Moreover, we prove that if the AM noise comes from the oscillator under test, it cannot be rejected by correlation. At least not with the schemes currently used. An example shows that at some critical frequencies the unwanted effect of AM noise is of the same order-if not greater--than the phase noise. Thus, experimental mistakes are around the corner.

Flow regimes in a T-mixer operating with a binary mixture

NASA Astrophysics Data System (ADS)

Camarri, Simone; Siconolfi, Lorenzo; Galletti, Chiara; Salvetti, Maria Vittoria

2015-11-01

Efficient mixing in small volumes is a key target in many processes. Among the most common micro-devices, passive T-shaped micro-mixers are widely used. For this reason, T-mixers have been studied in the literature and its working flow regimes have been identified. However, in most of the available theoretical studies it is assumed that only one working fluid is used, i.e. that the same fluid at the same thermodynamic conditions is entering the two inlet conduits of the mixer. Conversely, the practical use of micro-devices often involves the mixing of two different fluids or of the same fluid at different thermodynamic conditions. In this case flow regimes significantly different than those observed for a single working fluid may occur. The present work aims at investigating the flow regimes in a T-mixers when water at two different temperatures, i.e. having different viscosity and density, is entering the mixer. The effect of the temperature difference on the flow regimes in a 3D T-mixer is investigated by DNS and stability analysis and the results are compared to the case in which a single working fluid is employed.

Credit WCT. Original 21" x 2A" color negative is housed ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit WCT. Original 2-1" x 2-A" color negative is housed in the JPL Photography Laboratory, Pasadena, California. The mixing pot of the 150-gallon (Size 16-PVM) Baker-Perkins vertical mixer appears in its lowered position, exposing the mixer paddles. JPL employees Harold "Andy" Anderson and Ron Wright in protective clothing demonstrate how to scrape mixed propellant from mixer blades (JPL negative JPL10284BC, 27 January 1989) - Jet Propulsion Laboratory Edwards Facility, Mixer, Edwards Air Force Base, Boron, Kern County, CA

Ehf Multiple Beam Antennas.

DTIC Science & Technology

1981-09-21

acknowledge and thank A. R. Hislop and D. L. Saul, Code 9262, for their work on tbh mixer design and D. L. Chappelle and K. S. Maynard, Code 8124, for...MTT-28, p 555-563, June 1980 . 33 (a) Mixer matrix, 7 boards, 6-5 mixers, 1-7 mixers. (b) LO power split to boards, 7-way. rN’ o, Ro (c) N-way power...1966. 9. Saleh, A.A.M., Planar Electrically Symmetric N-Way Hybrid Power Dividers/ Combiners, IEEE T-MTT-28, p 555-563, June 1980 . 55

Diffusion-Cooled Tantalum Hot-Electron Bolometer Mixers

NASA Technical Reports Server (NTRS)

Skalare, Anders; McGrath, William; Bumble, Bruce; LeDuc, Henry

2004-01-01

A batch of experimental diffusion-cooled hot-electron bolometers (HEBs), suitable for use as mixers having input frequencies in the terahertz range and output frequencies up to about a gigahertz, exploit the superconducting/normal-conducting transition in a thin strip of tantalum. The design and operation of these HEB mixers are based on mostly the same principles as those of a prior HEB mixer that exploited the superconducting/normal- conducting transition in a thin strip of niobium and that was described elsewhere.

Design of Balanced Mixers for ALMA Band-10

NASA Astrophysics Data System (ADS)

Shitov, Sergey V.; Koryukin, Oleg V.; Uzawa, Yoshinori; Noguchi, Takashi; Uvarov, Andrey V.; Bukovski, Maksim A.; Cohn, Ilya A.

2007-06-01

Two variants of balanced mixer employing twin-SIS structure are under development for 787-950 GHz frequency range. Easy-to-use Geometry Transformation method for modeling of superconducting microstrips is developed, compared to referenced methods and used for design of the mixers. Lens-antenna mixer is based on cross-slot antenna; it does not need any intervening optics between its lens and sub-reflector of ALMA telescope; simple yet efficient composition of lens-antenna cartridge is suggested. Compact single-chamber balanced waveguide mixer employs two SIS chips and capacitive probe for LO injection; coupling above -3 dB and signal loss below -20 dB are expected. Need in shifting of resonance frequency of twin-SIS mixer towards top of the frequency band is predicted using Tucker's theory in large-signal approximation. TRX considerably below 200 K (DSB) is simulated using high-quality hybrid SIS junction for NbTiN/Nb - AlOx - Nb/Al for Jc = 12 kA/cm2.

Chaotic micromixers using two-layer crossing channels to exhibit fast mixing at low Reynolds numbers.

PubMed

Xia, H M; Wan, S Y M; Shu, C; Chew, Y T

2005-07-01

We report two chaotic micromixers that exhibit fast mixing at low Reynolds numbers in this paper. Passive mixers usually use the channel geometry to stir the fluids, and many previously reported designs rely on inertial effects which are only available at moderate Re. In this paper, we propose two chaotic micromixers using two-layer crossing channels. Both numerical and experimental studies show that the mixers are very efficient for fluid manipulation at low Reynolds numbers, such as stretching and splitting, folding and recombination, through which chaotic advection can be generated and the mixing is significantly promoted. More importantly, the generation of chaotic advection does not rely on the fluid inertial forces, so the mixers work well at very low Re. The mixers are benchmarked against a three-dimensional serpentine mixer. Results show that the latter is inefficient at Re = 0.2, while the new design exhibits rapid mixing at Re = 0.2 and at Re of O(10(-2)). The new mixer design will benefit various microfluidic systems.

A Low-Noise NbTiN Hot Electron Bolometer Mixer

NASA Technical Reports Server (NTRS)

Tong, C. Edward; Stern, Jeffrey; Megerian, Krikor; LeDuc, Henry; Sridharan, T. K.; Gibson, Hugh; Blundell, Raymond

2001-01-01

Hot electron bolometer (HEB) mixer elements, based on niobium titanium nitride (NbTiN) thin film technology, have been fabricated on crystalline quartz substrates over a 20 nm thick AlN buffer layer. The film was patterned by optical lithography, yielding bolometer elements that measure about 1 micrometer long and between 2 and 12 micrometers wide. These mixer chips were mounted in a fixed-tuned waveguide mixer block, and tested in the 600 and 800 GHz frequency range. The 3-dB output bandwidth of these mixers was determined to be about 2.5 GHz and we measured a receiver noise temperature of 270 K at 630 GHz using an intermediate frequency of 1.5 GHz. The receiver has excellent amplitude stability and the noise temperature measurements are highly repeatable. An 800 GHz receiver incorporating one of these mixer chips has recently been installed at the Sub-Millimeter Telescope in Arizona for field test and for astronomical observations.

A Planar Microfluidic Mixer Based on Logarithmic Spirals

PubMed Central

Scherr, Thomas; Quitadamo, Christian; Tesvich, Preston; Park, Daniel Sang-Won; Tiersch, Terrence; Hayes, Daniel; Choi, Jin-Woo; Nandakumar, Krishnaswamy

2013-01-01

A passive, planar micromixer design based on logarithmic spirals is presented. The device was fabricated using polydimethylsiloxane soft photolithography techniques, and mixing performance was characterized via numerical simulation and fluorescent microscopy. Mixing efficiency initially declined as Reynolds number increased, and this trend continued until a Reynolds number of 15 where a minimum was reached at 53%. Mixing efficiency then began to increase reaching a maximum mixing efficiency of 86% at Re = 67. Three-dimensional simulations of fluid mixing in this design were compared to other planar geometries such as the Archimedes spiral and Meandering-S mixers. The implementation of logarithmic curvature offers several unique advantages that enhance mixing, namely a variable cross-sectional area and a logarithmically varying radius of curvature that creates 3-D Dean vortices. These flow phenomena were observed in simulations with multilayered fluid folding and validated with confocal microscopy. This design provides improved mixing performance over a broader range of Reynolds numbers than other reported planar mixers, all while avoiding external force fields, more complicated fabrication processes, and the introduction of flow obstructions or cavities that may unintentionally affect sensitive or particulate-containing samples. Due to the planar design requiring only single-step lithographic features, this compact geometry could be easily implemented into existing micro-total analysis systems requiring effective rapid mixing. PMID:23956497

A planar microfluidic mixer based on logarithmic spirals

NASA Astrophysics Data System (ADS)

Scherr, Thomas; Quitadamo, Christian; Tesvich, Preston; Sang-Won Park, Daniel; Tiersch, Terrence; Hayes, Daniel; Choi, Jin-Woo; Nandakumar, Krishnaswamy; Monroe, W. Todd

2012-05-01

A passive, planar micromixer design based on logarithmic spirals is presented. The device was fabricated using polydimethylsiloxane soft photolithography techniques, and mixing performance was characterized via numerical simulation and fluorescent microscopy. Mixing efficiency initially declined as the Reynolds number increased, and this trend continued until a Reynolds number of 15 where a minimum was reached at 53%. Mixing efficiency then began to increase reaching a maximum mixing efficiency of 86% at Re = 67. Three-dimensional (3D) simulations of fluid mixing in this design were compared to other planar geometries such as the Archimedes spiral and Meandering-S mixers. The implementation of logarithmic curvature offers several unique advantages that enhance mixing, namely a variable cross-sectional area and a logarithmically varying radius of curvature that creates 3D Dean vortices. These flow phenomena were observed in simulations with multilayered fluid folding and validated with confocal microscopy. This design provides improved mixing performance over a broader range of Reynolds numbers than other reported planar mixers, all while avoiding external force fields, more complicated fabrication processes and the introduction of flow obstructions or cavities that may unintentionally affect sensitive or particulate-containing samples. Due to the planar design requiring only single-step lithographic features, this compact geometry could be easily implemented into existing micro-total analysis systems requiring effective rapid mixing.

21 CFR 868.5330 - Breathing gas mixer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Breathing gas mixer. 868.5330 Section 868.5330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5330 Breathing gas mixer. (a...

21 CFR 868.5330 - Breathing gas mixer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Breathing gas mixer. 868.5330 Section 868.5330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5330 Breathing gas mixer. (a...

Variable volume combustor with center hub fuel staging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ostebee, Heath Michael; McConnaughhay, Johnie Franklin; Stewart, Jason Thurman

The present application and the resultant patent provide a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a center hub for providing the flow of fuel therethrough. The center hub may include a first supply circuit for a first micro-mixer fuel nozzle and a second supply circuit for a second micro-mixer fuel nozzle.

Noise Reduction with Lobed Mixers: Nozzle-Length and Free-Jet Speed Effects

NASA Technical Reports Server (NTRS)

Mengle, Vinod G.; Dalton, William N.; Bridges, James C.; Boyd, Kathy C.

1997-01-01

Acoustic test results are presented for 1/4th-scaled nozzles with internal lobed mixers used for reduction of subsonic jet noise of turbofan engines with bypass ratio above 5 and jet speeds up to 830 ft/s. One coaxial and three forced lobe mixers were tested with variations in lobe penetration, cut-outs in lobe-sidewall, lobe number and nozzle-length. Measured exit flow profiles and thrusts are used to assist the inferences from acoustic data. It is observed that lobed mixers reduce the low-frequency noise due to more uniformly mixed exit flow; but they may also increase the high-frequency noise at peak perceived noise (PNL) angle and angles upstream of it due to enhanced mixing inside the nozzle. Cut-outs and low lobe penetration reduce the annoying portion of the spectrum but lead to less uniform exit flow. Due to the dominance of internal duct noise in unscalloped, high-penetration mixers their noise is not reduced as much with increase in free-jet speed as that of coaxial or cut-out lobed mixers. The latter two mixers also show no change in PNL over the wide range of nozzle-lengths tested because most of their noise sources are outside the nozzle; whereas, the former show an increase in noise with decrease in nozzle-length.

Low-noise and wideband hot-electron superconductive mixer for terahertz frequencies

NASA Astrophysics Data System (ADS)

Karasik, Boris S.; Skalare, Anders; McGrath, William R.; Bumble, Bruce; Leduc, Henry G.; Barner, J. B.; Kleinsasser, Alan W.; Burke, P. J.; Schoelkopf, Robert J.; Prober, Daniel E.

1998-11-01

Superconductive hot-electron bolometer (HEB) mixers have been built and tested in the frequency range from 1.1 THz to 2.5 THz. The mixer device is a 0.15 - 0.3 micrometer microbridge made from a 10 nm thick Nb film. This device employs diffusion as a cooling mechanism for hot electrons. The double sideband noise temperature was measured to be less than or equal to 3000 K at 2.5 THz and the mixer IF bandwidth is expected to be at least 10 GHz for a 0.1 micrometer long device. The local oscillator (LO) power dissipated in the HEB microbridge was 20 - 100 nW. Further improvement of the mixer characteristics can be potentially achieved by using Al microbridges. The advantages and parameters of such devices are evaluated. The HEB mixer is a primary candidate for ground based, airborne and spaceborne heterodyne instruments at THz frequencies. HEB receivers are planned for use on the NASA Stratospheric Observatory for Infrared Astronomy (SOFIA) and the ESA Far Infrared and Submillimeter Space Telescope (FIRST). The prospects of a submicron-size YBa2Cu3O7-(delta ) (YBCO) HEB are discussed. The expected LO power of 1 - 10 (mu) W and SSB noise temperature of approximately equals 2000 K may make this mixer attractive for various remote sensing applications.

Phase 1 Development Testing of the Advanced Manufacturing Demonstrator Engine

NASA Technical Reports Server (NTRS)

Case, Nicholas L.; Eddleman, David E.; Calvert, Marty R.; Bullard, David B.; Martin, Michael A.; Wall, Thomas R.

2016-01-01

The Additive Manufacturing Development Breadboard Engine (BBE) is a pressure-fed liquid oxygen/pump-fed liquid hydrogen (LOX/LH2) expander cycle engine that was built and operated by NASA at Marshall Space Flight Center's East Test Area. The breadboard engine was conceived as a technology demonstrator for the additive manufacturing technologies for an advanced upper stage prototype engine. The components tested on the breadboard engine included an ablative chamber, injector, main fuel valve, turbine bypass valve, a main oxidizer valve, a mixer and the fuel turbopump. All parts minus the ablative chamber were additively manufactured. The BBE was successfully hot fire tested seven times. Data collected from the test series will be used for follow on demonstration tests with a liquid oxygen turbopump and a regeneratively cooled chamber and nozzle.

Fabricating microfluidic valve master molds in SU-8 photoresist

NASA Astrophysics Data System (ADS)

Dy, Aaron J.; Cosmanescu, Alin; Sluka, James; Glazier, James A.; Stupack, Dwayne; Amarie, Dragos

2014-05-01

Multilayer soft lithography has become a powerful tool in analytical chemistry, biochemistry, material and life sciences, and medical research. Complex fluidic micro-circuits require reliable components that integrate easily into microchips. We introduce two novel approaches to master mold fabrication for constructing in-line micro-valves using SU-8. Our fabrication techniques enable robust and versatile integration of many lab-on-a-chip functions including filters, mixers, pumps, stream focusing and cell-culture chambers, with in-line valves. SU-8 created more robust valve master molds than the conventional positive photoresists used in multilayer soft lithography, but maintained the advantages of biocompatibility and rapid prototyping. As an example, we used valve master molds made of SU-8 to fabricate PDMS chips capable of precisely controlling beads or cells in solution.

Microchip systems for immunoassay: an integrated immunoreactor with electrophoretic separation for serum theophylline determination.

PubMed

Chiem, N H; Harrison, D J

1998-03-01

A glass microchip is described in which reagents and serum samples for competitive immunoassay of serum theophylline can be mixed, reacted, separated, and analyzed. The device functions as an automated microfluidic immunoassay system, creating a lab-on-a-chip. Electroosmotic pumping was used to control first the mixing of 50-fold-diluted serum sample with labeled theophylline tracer in a 1:1 ratio, followed by 1:1 mixing and reaction with anti-theophylline antibody. The 51-nL on-chip mixer gave the same concentration as dilution performed off-chip, within 3%. A 100-pL plug of the reacted solution was then injected into an electrophoresis separation channel integrated within the same chip. Measurements of free and bound tracer by fluorescence detection gave linear calibration curves of signal vs log[theophylline] between 0 and 40 mg/L, with a slope of 0.52 +/- 0.03 and an intercept of -0.04 +/- 0.04 after a 90-s reaction time. A detection limit of 0.26 mg/L in serum (expressed before the dilution step, actual concentration of 1.3 micrograms/L at the detector) was obtained. Recovery values were 107% +/- 8% for 15 mg/L serum samples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mirzaei, B.; Silva, J. R. G.; Hayton, D.

We present an 8-beam local oscillator (LO) for the astronomically significant [OI] line at 4.7 THz. The beams are generated using a quantum cascade laser (QCL) in combination with a Fourier phase grating. The grating is fully characterized using a third order distributed feedback (DFB) QCL with a single mode emission at 4.7 THz as the input. The measured diffraction efficiency of 74.3% is in an excellent agreement with the calculated result of 75.4% using a 3D simulation. We show that the power distribution among the diffracted beams is uniform enough for pumping an array receiver. To validate the gratingmore » bandwidth, we apply a far-infrared (FIR) gas laser emission at 5.3 THz as the input and find a very similar performance in terms of efficiency, power distribution, and spatial configuration of the diffracted beams. Both results represent the highest operating frequencies of THz phase gratings reported in the literature. By injecting one of the eight diffracted 4.7 THz beams into a superconducting hot electron bolometer (HEB) mixer, we find that the coupled power, taking the optical loss into account, is in consistency with the QCL power value.« less

8-beam local oscillator array at 4.7 THz generated by a phase grating and a quantum cascade laser.

PubMed

Mirzaei, B; Silva, J R G; Hayton, D; Groppi, C; Kao, T Y; Hu, Q; Reno, J L; Gao, J R

2017-11-27

We present an 8-beam local oscillator (LO) for the astronomically significant [OI] line at 4.7 THz. The beams are generated using a quantum cascade laser (QCL) in combination with a Fourier phase grating. The grating is fully characterized using a third order distributed feedback (DFB) QCL with a single mode emission at 4.7 THz as the input. The measured diffraction efficiency of 74.3% is in an excellent agreement with the calculated result of 75.4% using a 3D simulation. We show that the power distribution among the diffracted beams is uniform enough for pumping an array receiver. To validate the grating bandwidth, we apply a far-infrared (FIR) gas laser emission at 5.3 THz as the input and find a very similar performance in terms of efficiency, power distribution, and spatial configuration of the diffracted beams. Both results represent the highest operating frequencies of THz phase gratings reported in the literature. By injecting one of the eight diffracted 4.7 THz beams into a superconducting hot electron bolometer (HEB) mixer, we find that the coupled power, taking the optical loss into account, is in consistency with the QCL power value.

Design and implementation of a low-power SOI CMOS receiver

NASA Astrophysics Data System (ADS)

Zencir, Ertan

There is a strong demand for wireless communications in civilian and military applications, and space explorations. This work attempts to implement a low-power, high-performance fully-integrated receiver for deep space communications using Silicon on Insulator (SOI) CMOS technology. Design and implementation of a UHF low-IF receiver front-end in a 0.35-mum SOI CMOS technology are presented. Problems and challenges in implementing a highly integrated receiver at UHF are identified. Low-IF architecture, suitable for low-power design, has been adopted to mitigate the noise at the baseband. Design issues of the receiver building blocks including single-ended and differential LNA's, passive and active mixers, and variable gain/bandwidth complex filters are discussed. The receiver is designed to have a variable conversion gain of more than 100 dB with a 70 dB image rejection and a power dissipation of 45 mW from a 2.5-V supply. Design and measured performance of the LNA's, and the mixer are presented. Measurement results of RF front-end blocks including a single-ended LNA, a differential LNA, and a double-balanced mixer demonstrate the low power realizability of RF front-end circuits in SOI CMOS technology. We also report on the design and simulation of the image-rejecting complex IF filter and the full receiver circuit. Gain, noise, and linearity performance of the receiver components prove the viability of fully integrated low-power receivers in SOI CMOS technology.

Low Emissions RQL Flametube Combustor Component Test Results

NASA Technical Reports Server (NTRS)

Holdeman, James D.; Chang, Clarence T.

2001-01-01

This report describes and summarizes elements of the High Speed Research (HSR) Low Emissions Rich burn/Quick mix/Lean burn (RQL) flame tube combustor test program. This test program was performed at NASA Glenn Research Center circa 1992. The overall objective of this test program was to demonstrate and evaluate the capability of the RQL combustor concept for High Speed Civil Transport (HSCT) applications with the goal of achieving NOx emission index levels of 5 g/kg-fuel at representative HSCT supersonic cruise conditions. The specific objectives of the tests reported herein were to investigate component performance of the RQL combustor concept for use in the evolution of ultra-low NOx combustor design tools. Test results indicated that the RQL combustor emissions and performance at simulated supersonic cruise conditions were predominantly sensitive to the quick mixer subcomponent performance and not sensitive to fuel injector performance. Test results also indicated the mixing section configuration employing a single row of circular holes was the lowest NOx mixer tested probably due to the initial fast mixing characteristics of this mixing section. However, other quick mix orifice configurations such as the slanted slot mixer produced substantially lower levels of carbon monoxide emissions most likely due to the enhanced circumferential dispersion of the air addition. Test results also suggested that an optimum momentum-flux ratio exists for a given quick mix configuration. This would cause undesirable jet under- or over-penetration for test conditions with momentum-flux ratios below or above the optimum value. Tests conducted to assess the effect of quick mix flow area indicated that reduction in the quick mix flow area produced lower NOx emissions at reduced residence time, but this had no effect on NOx emissions measured at similar residence time for the configurations tested.

Effect of mixing time and speed on experimental baking and dough testing with a 200g pin-mixer

USDA-ARS?s Scientific Manuscript database

Under mixing or over mixing the dough results in varied experimental loaf volumes. Bread preparation requires a trained baker to evaluate dough development and determine stop points of mixer. Instrumentation and electronic control of the dough mixer would allow for automatic mixing. This study us...

The Strength Analysis of Differential Planetary Gears of Gearbox for Concrete Mixer Truck

NASA Astrophysics Data System (ADS)

Bae, M. H.; Bae, T. Y.; Kim, D. J.

2018-03-01

The power train of mixer gearbox for concrete mixer truck includes differential planetary gears to get large reduction ratio for operating mixer a drum and simple structure. The planetary gears are very important part of a mixer gearbox where strength problems namely gear bending stress, gear compressive stress and scoring failure are the main concern. In the present study, calculating specifications of the differential planetary gears and analyzing the gear bending and compressive stresses as well as scoring factor of the differential planetary gears gearbox for an optimal design of the mixer gearbox in respect to cost and reliability are investigated. The analyses of actual gear bending and compressive stresses of the differential planetary gears using Lewes & Hertz equation and verifications of the calculated specifications of the differential planetary gears evaluate the results with the data of allowable bending and compressive stress from the Stress-No. of cycles curves of gears. In addition, we also analyze actual gear scoring factor as well as evaluate the possibility of scoring failure of the differential planetary gear.

Highly efficient evaluation of a gas mixer using a hollow waveguide based laser spectral sensor

NASA Astrophysics Data System (ADS)

Du, Z.; Yang, X.; Li, J.; Yang, Y.; Qiao, C.

2017-05-01

This paper aims to provide a fast, sensitive, and accurate characterization of a Mass Flow Controller (MFC) based gas mixer. The gas mixer was evaluated by using a hollow waveguide based laser spectral sensor with high efficiency. Benefiting from the sensor's fast response, high sensitivity and continuous operation, multiple key parameters of the mixer, including mixing uncertainty, linearity, and response time, were acquired by a one-round test. The test results show that the mixer can blend multi-compound gases quite efficiently with an uncertainty of 1.44% occurring at a flow rate of 500 ml/min, with the linearity of 0.998 43 and the response time of 92.6 s. The results' reliability was confirmed by the relative measurement of gas concentration, in which the isolation of the sensor's uncertainty was conducted. The measured uncertainty has shown well coincidence with the theoretical uncertainties of the mixer, which proves the method to be a reliable characterization. Consequently, this sort of laser based characterization's wide appliance on gas analyzer's evaluations is demonstrated.

A Comparison of Combustion Dynamics for Multiple 7-Point Lean Direct Injection Combustor Configurations

NASA Technical Reports Server (NTRS)

Tacina, K. M.; Hicks, Y. R.

2017-01-01

The combustion dynamics of multiple 7-point lean direct injection (LDI) combustor configurations are compared. LDI is a fuel-lean combustor concept for aero gas turbine engines in which multiple small fuel-air mixers replace one traditionally-sized fuel-air mixer. This 7-point LDI configuration has a circular cross section, with a center (pilot) fuel-air mixer surrounded by six outer (main) fuel-air mixers. Each fuel-air mixer consists of an axial air swirler followed by a converging-diverging venturi. A simplex fuel injector is inserted through the center of the air swirler, with the fuel injector tip located near the venturi throat. All 7 fuel-air mixers are identical except for the swirler blade angle, which varies with the configuration. Testing was done in a 5-atm flame tube with inlet air temperatures from 600 to 800 F and equivalence ratios from 0.4 to 0.7. Combustion dynamics were measured using a cooled PCB pressure transducer flush-mounted in the wall of the combustor test section.

Highly efficient evaluation of a gas mixer using a hollow waveguide based laser spectral sensor.

PubMed

Du, Z; Yang, X; Li, J; Yang, Y; Qiao, C

2017-05-01

This paper aims to provide a fast, sensitive, and accurate characterization of a Mass Flow Controller (MFC) based gas mixer. The gas mixer was evaluated by using a hollow waveguide based laser spectral sensor with high efficiency. Benefiting from the sensor's fast response, high sensitivity and continuous operation, multiple key parameters of the mixer, including mixing uncertainty, linearity, and response time, were acquired by a one-round test. The test results show that the mixer can blend multi-compound gases quite efficiently with an uncertainty of 1.44% occurring at a flow rate of 500 ml/min, with the linearity of 0.998 43 and the response time of 92.6 s. The results' reliability was confirmed by the relative measurement of gas concentration, in which the isolation of the sensor's uncertainty was conducted. The measured uncertainty has shown well coincidence with the theoretical uncertainties of the mixer, which proves the method to be a reliable characterization. Consequently, this sort of laser based characterization's wide appliance on gas analyzer's evaluations is demonstrated.

Turbofan forced mixer lobe flow modeling. 2: Three-dimensional inviscid mixer analysis (FLOMIX)

NASA Technical Reports Server (NTRS)

Barber, T.

1988-01-01

A three-dimensional potential analysis (FLOMIX) was formulated and applied to the inviscid flow over a turbofan foced mixer. The method uses a small disturbance formulation to analytically uncouple the circumferential flow from the radial and axial flow problem, thereby reducing the analysis to the solution of a series of axisymmetric problems. These equations are discretized using a flux volume formulation along a Cartesian grid. The method extends earlier applications of the Cartesian method to complex cambered geometries. The effects of power addition are also included within the potential formulation. Good agreement is obtained with an alternate small disturbance analysis for a high penetration symmetric mixer in a planar duct. In addition, calculations showing pressure distributions and induced secondary vorticity fields are presented for practical trubofan mixer configurations, and where possible, comparison was made with available experimental data. A detailed description of the required data input and coordinate definition is presented along with a sample data set for a practical forced mixer configuration. A brief description of the program structure and subroutines is also provided.

Embedding impedance approximations in the analysis of SIS mixers

NASA Technical Reports Server (NTRS)

Kerr, A. R.; Pan, S.-K.; Withington, S.

1992-01-01

Future millimeter-wave radio astronomy instruments will use arrays of many SIS receivers, either as focal plane arrays on individual radio telescopes, or as individual receivers on the many antennas of radio interferometers. Such applications will require broadband integrated mixers without mechanical tuners. To produce such mixers, it will be necessary to improve present mixer design techniques, most of which use the three-frequency approximation to Tucker's quantum mixer theory. This paper examines the adequacy of three approximations to Tucker's theory: (1) the usual three-frequency approximation which assumes a sinusoidal LO voltage at the junction, and a short-circuit at all frequencies above the upper sideband; (2) a five-frequency approximation which allows two LO voltage harmonics and five small-signal sidebands; and (3) a quasi five-frequency approximation in which five small-signal sidebands are allowed, but the LO voltage is assumed sinusoidal. These are compared with a full harmonic-Newton solution of Tucker's equations, including eight LO harmonics and their corresponding sidebands, for realistic SIS mixer circuits. It is shown that the accuracy of the three approximations depends strongly on the value of omega R(sub N)C for the SIS junctions used. For large omega R(sub N)C, all three approximations approach the eight-harmonic solution. For omega R(sub N)C values in the range 0.5 to 10, the range of most practical interest, the quasi five-frequency approximation is a considerable improvement over the three-frequency approximation, and should be suitable for much design work. For the realistic SIS mixers considered here, the five-frequency approximation gives results very close to those of the eight-harmonic solution. Use of these approximations, where appropriate, considerably reduces the computational effort needed to analyze an SIS mixer, and allows the design and optimization of mixers using a personal computer.

Influence of pressure driven secondary flows on the behavior of turbofan forced mixers

NASA Technical Reports Server (NTRS)

Anderson, B.; Povinelli, L.; Gerstenmaier, W.

1980-01-01

A finite difference procedure was developed to analyze the three dimensional subsonic turbulent flows in turbofan forced mixer nozzles. The method is based on a decomposition of the velocity field into primary and secondary flow components which are determined by solution of the equations governing primary momentum, secondary vorticity, thermal energy, and continuity. Experimentally, a strong secondary flow pattern was identified which is associated with the radial inflow and outflow characteristics of the core and fan streams and forms a very strong vortex system aligned with the radial interface between the core and fan regions. A procedure was developed to generate a similar generic secondary flow pattern in terms of two constants representing the average radial outflow or inflow in the core and fan streams as a percentage of the local streamwise velocity. This description of the initial secondary flow gave excellent agreement with experimental data. By identifying the nature of large scale secondary flow structure and associating it with characteristic mixer nozzle behavior, it is felt that the cause and effect relationship between lobe design and nozzle performance can be understood.

Turbofan forced mixer-nozzle internal flowfield. Volume 1: A benchmark experimental study

NASA Technical Reports Server (NTRS)

Paterson, R. W.

1982-01-01

An experimental investigation of the flow field within a model turbofan forced mixer nozzle is described. Velocity and thermodynamic state variable data for use in assessing the accuracy and assisting the further development of computational procedures for predicting the flow field within mixer nozzles are provided. Velocity and temperature data suggested that the nozzle mixing process was dominated by circulations (secondary flows) of a length scale on the order the lobe dimensions which were associated with strong radial velocities observed near the lobe exit plane. The 'benchmark' model mixer experiment conducted for code assessment purposes is discussed.

Terahertz Radiometer for Outer Planet and Moon Atmospheres (TROPA)

NASA Technical Reports Server (NTRS)

Schlecht, E. T.; Jamnejad, V.; Jarnot, R. F.; Raffanti, R.; Lin, R.

2012-01-01

We are developing a prototype instrument platform to demonstrate the feasibility of a wideband spectrometer for planetary applications under a three-year NASA research program. This development focuses on three specific areas needing advancement. First, the terahertz portion consists of an optical bench with dual heterodyne Schottky-mixer based receivers, one for each band. The beams entering the horns of the two receivers are de-multiplexed from the input beam by a polarizing beam splitter. The blocks containing the 560 and 1200 GHz mixer are more highly integrated than previous space instruments to reduce mass and volume. The receivers take a fundamental pump frequency near 30 GHz and multiply up to the submillimeter range. Second, a rapid-tuning, low-phase noise, and low-power 33 GHz range LO synthesizer is being prototyped. The low phase noise requirement is needed because of the factor of 36 multiplication to reach 1200 GHz, giving a requirement that the integrated phase noise from 100 kHz up be less than 0.6 degrees. The synthesizer will require about 6 watts. Finally, we are developing an advanced polyphase filter back-end spectrum analyzer with a bandwidth of 750 MHz, and power consumption of about 3 Watts and 4096 channels. This system is based on a simple three-chip architecture, having a commercial 1.5 GS/s analog-to-digital converter, an ASIC to do the filtering and an advanced FPGA for data processing and control.

Design and simulation of the micromixer with chaotic advection in twisted microchannels.

PubMed

Jen, Chun-Ping; Wu, Chung-Yi; Lin, Yu-Cheng; Wu, Ching-Yi

2003-05-01

Chaotic mixers with twisted microchannels were designed and simulated numerically in the present study. The phenomenon whereby a simple Eulerian velocity field may generate a chaotic response in the distribution of a Lagrangian marker is termed chaotic advection. Dynamic system theory indicates that chaotic particle motion can occur when a velocity field is either two-dimensional and time-dependent, or three-dimensional. In the present study, micromixers with three-dimensional structures of the twisted microchannel were designed in order to induce chaotic mixing. In addition to the basic T-mixer, three types of micromixers with inclined, oblique and wavelike microchannels were investigated. In the design of each twisted microchannel, the angle of the channels' bottoms alternates in each subsection. When the fluids enter the twisted microchannels, the flow sways around the varying structures within the microchannels. The designs of the twisted microchannels provide a third degree of freedom to the flow field in the microchannel. Therefore, chaotic regimes that lead to chaotic mixing may arise. The numerical results indicate that mixing occurs in the main channel and progressively larger mixing lengths are required as the Peclet number increased. The swaying of the flow in the twisted microchannel causes chaotic advection. Among the four micromixer designs, the micromixer with the inclined channel most improved mixing. Furthermore, using the inclined mixer with six subsections yielded optimum performance, decreasing the mixing length by up to 31% from that of the basic T-mixer.

Variable volume combustor with nested fuel manifold system

DOEpatents

McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward; Ostebee, Heath Michael

2016-09-13

The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles, a fuel manifold system in communication with the micro-mixer fuel nozzles to deliver a flow of fuel thereto, and a linear actuator to maneuver the micro-mixer fuel nozzles and the fuel manifold system.

Airfoil-shaped micro-mixers for reducing fouling on membrane surfaces

DOEpatents

Ho, Clifford K; Altman, Susan J; Clem, Paul G; Hibbs, Michael; Cook, Adam W

2012-10-23

An array of airfoil-shaped micro-mixers that enhances fluid mixing within permeable membrane channels, such as used in reverse-osmosis filtration units, while minimizing additional pressure drop. The enhanced mixing reduces fouling of the membrane surfaces. The airfoil-shaped micro-mixer can also be coated with or comprised of biofouling-resistant (biocidal/germicidal) ingredients.

Dewatering of contaminated river sediments

NASA Technical Reports Server (NTRS)

Church, Ronald H.; Smith, Carl W.; Scheiner, Bernard J.

1994-01-01

Dewatering of slurries has been successfully accomplished by the proper use of polymers in flocculating the fine particulate matter suspended in mineral processing streams. The U.S. Bureau of Mines (USBM) entered into a cooperative research effort with the U.S. Army Corps of Engineers (Corps) for the purpose of testing and demonstrating the applicability of mining flocculation technology to dredging activities associated with the removal of sediments from navigable waterways. The Corps has the responsibility for maintaining the navigable waterways in the United States. Current technology relies primarily on dredging operations which excavate the material from the bottom of waterways. The Corps is testing new dredging technology which may reduce resuspension of sediments by the dredging operation. Pilot plant dredging equipment was tested by the Corps which generated larger quantities of water when compared to conventional equipment, such as the clam shell. The transportation of this 'excess' water adds to the cost of sediment removal. The process developed by the USBM consists of feed material from the barge being pumped through a 4-in line by a centrifugal pump and exiting through a 4-in PVC delivery system. A 1,000-gal fiberglass tank was used to mix the polymer concentrate. The polymer was pumped through a 1-in line using a variable speed progressive cavity pump and introduced to the 4-in feed line prior to passing through a 6-in by 2-ft static mixer. The polymer/feed slurry travels to the clarifying tank where the flocculated material settled to the bottom and allowed 'clean' water to exit the overflow. A pilot scale flocculation unit was operated on-site at the Corps' 'Confined Disposal Facility' in Buffalo, NY.

Fabrication and characterization of 8.87 THz schottky barrier mixer diodes for mixer

NASA Astrophysics Data System (ADS)

Wang, Wenjie; Li, Qian; An, Ning; Tong, Xiaodong; Zeng, Jianping

2018-04-01

In this paper we report on the fabrication and characterization of GaAs-based THz schottky barrier mixer diodes. Considering the analyzed results as well as fabrication cost and complexity, a group of trade-off parameters was determined. Electron-beam lithography and air-bridge technique have been used to obtain schottky diodes with a cut off frequency of 8.87 THz. Equivalent values of series resistance, ideal factor and junction capacitance of 10.2 (1) Ω, 1.14 (0.03) and 1.76(0.03) respectively have been measured for 0.7um diameter anode devices by DC and RF measurements. The schottky barrier diodes fabrication process is fully planar and very suitable for integration in THz frequency multiplier and mixer circuits. THz Schottky barrier diodes based on such technology with 2 μm diameter anodes have been tested at 1.6 THz in a sub-harmonic mixer.

CFD simulation of vertical linear motion mixing in anaerobic digester tanks.

PubMed

Meroney, Robert N; Sheker, Robert E

2014-09-01

Computational fluid dynamics (CFD) was used to simulate the mixing characteristics of a small circular anaerobic digester tank (diameter 6 m) equipped sequentially with 13 different plunger type vertical linear motion mixers and two different type internal draft-tube mixers. Rates of mixing of step injection of tracers were calculated from which active volume (AV) and hydraulic retention time (HRT) could be calculated. Washout characteristics were compared to analytic formulae to estimate any presence of partial mixing, dead volume, short-circuiting, or piston flow. Active volumes were also estimated based on tank regions that exceeded minimum velocity criteria. The mixers were ranked based on an ad hoc criteria related to the ratio of AV to unit power (UP) or AV/UP. The best plunger mixers were found to behave about the same as the conventional draft-tube mixers of similar UP.

Gas turbine engine combustor can with trapped vortex cavity

DOEpatents

Burrus, David Louis; Joshi, Narendra Digamber; Haynes, Joel Meier; Feitelberg, Alan S.

2005-10-04

A gas turbine engine combustor can downstream of a pre-mixer has a pre-mixer flowpath therein and circumferentially spaced apart swirling vanes disposed across the pre-mixer flowpath. A primary fuel injector is positioned for injecting fuel into the pre-mixer flowpath. A combustion chamber surrounded by an annular combustor liner disposed in supply flow communication with the pre-mixer. An annular trapped dual vortex cavity located at an upstream end of the combustor liner is defined between an annular aft wall, an annular forward wall, and a circular radially outer wall formed therebetween. A cavity opening at a radially inner end of the cavity is spaced apart from the radially outer wall. Air injection first holes are disposed through the forward wall and air injection second holes are disposed through the aft wall. Fuel injection holes are disposed through at least one of the forward and aft walls.

Nonlinear Modeling and Control of a Propellant Mixer

NASA Technical Reports Server (NTRS)

Barbieri, Enrique; Richter, Hanz; Figueroa, Fernando

2003-01-01

A mixing chamber used in rocket engine combustion testing at NASA Stennis Space Center is modeled by a second order nonlinear MIMO system. The mixer is used to condition the thermodynamic properties of cryogenic liquid propellant by controlled injection of the same substance in the gaseous phase. The three inputs of the mixer are the positions of the valves regulating the liquid and gas flows at the inlets, and the position of the exit valve regulating the flow of conditioned propellant. The outputs to be tracked and/or regulated are mixer internal pressure, exit mass flow, and exit temperature. The outputs must conform to test specifications dictated by the type of rocket engine or component being tested downstream of the mixer. Feedback linearization is used to achieve tracking and regulation of the outputs. It is shown that the system is minimum-phase provided certain conditions on the parameters are satisfied. The conditions are shown to have physical interpretation.

Quasi-optical antenna-mixer-array design for terahertz frequencies

NASA Technical Reports Server (NTRS)

Guo, Yong; Potter, Kent A.; Rutledge, David B.

1992-01-01

A new quasi-optical antenna-mixer-array design for terahertz frequencies is presented. In the design, antenna and mixer are combined into an entity, based on the technology in which millimeter-wave horn antenna arrays have been fabricated in silicon wafers. It consists of a set of forward- and backward-looking horns made with a set of silicon wafers. The front side is used to receive incoming signal, and the back side is used to feed local oscillator signal. Intermediate frequency is led out from the side of the array. Signal received by the horn array is picked up by antenna probes suspended on thin silicon-oxynitride membranes inside the horns. Mixer diodes will be located on the membranes inside the horns. Modeling of such an antenna-mixer-array design is done on a scaled model at microwave frequencies. The impedance matching, RF and LO isolation, and patterns of the array have been tested and analyzed.

A Robust High-Performance GPS L1 Receiver with Single-stage Quadrature Redio-Frequency Circuit

NASA Astrophysics Data System (ADS)

Liu, Jianghua; Xu, Weilin; Wan, Qinq; Liu, Tianci

2018-03-01

A low power current reuse single-stage quadrature raido-frequency part (SQRF) is proposed for GPS L1 receiver in 180nm CMOS process. The proposed circuit consists of LNA, Mixer, QVCO, is called the QLMV cell. A two blocks stacked topology is adopted in this design. The parallel QVCO and mixer placed on the top forms the upper stacked block, and the LNA placed on the bottom forms the other stacked block. The two blocks share the current and achieve low power performance. To improve the stability, a float current source is proposed. The float current isolated the local oscillation signal and the input RF signal, which bring the whole circuit robust high-performance. The result shows conversion gain is 34 dB, noise figure is three dB, the phase noise is -110 dBc/Hz at 1MHz and IIP3 is -20 dBm. The proposed circuit dissipated 1.7mW with 1 V supply voltage.

A novel micromixer based on the alternating current-flow field effect transistor.

PubMed

Wu, Yupan; Ren, Yukun; Tao, Ye; Hou, Likai; Hu, Qingming; Jiang, Hongyuan

2016-12-20

Induced-charge electroosmosis (ICEO) phenomena have been attracting considerable attention as a means for pumping and mixing in microfluidic systems with the advantage of simple structures and low-energy consumption. We propose the first effort to exploit a fixed-potential ICEO flow around a floating electrode for microfluidic mixing. In analogy with the field effect transistor (FET) in microelectronics, the floating electrode act as a "gate" electrode for generating asymmetric ICEO flow and thus the device is called an AC-flow FET (AC-FFET). We take advantage of a tandem electrode configuration containing two biased center metal strips arranged in sequence at the bottom of the channel to generate asymmetric vortexes. The current device is manufactured on low-cost glass substrates via an easy and reliable process. Mixing experiments were conducted in the proposed device and the comparison between simulation and experimental results was also carried out, which indicates that the micromixer permits an efficient mixing effect. The mixing performance can be further enhanced by the application of a suitable phase difference between the driving electrode and the gate electrode or a square wave signal. Finally, we performed a critical analysis of the proposed micromixer in comparison with different mixer designs using a comparative mixing index (CMI). The novel methods put forward here offer a simple solution to mixing issues in microfluidic systems.

An easily integrative and efficient micromixer and its application to the spectroscopic detection of glucose-catalyst reactions.

PubMed

Kim, D J; Oh, H J; Park, T H; Choo, J B; Lee, S H

2005-03-01

The focus of this paper is on the fabrication of a PDMS-based passive efficient micromixer to be easily integrated into the other on-chip microfluidic system. The mixing is achieved by "strong stretching and folding," which employs a three-dimensional microchannel structure. By the simultaneously vertical and transversal dispersion of fluids, strong advection is developed. Owing to this powerful mixing performance (more than 70% of the mixing is accomplished within 2.3 mm over a wide range of Reynold number (Re)), the smaller integrative mixer can be realized. The feasibility and the potential usefulness of an integrative micromixer were evaluated by incorporating two mixers into the microchannel for the spectroscopic detection of a glucose-catalyst reaction. The results demonstrate a promising performance for diverse applications in the assay or synthesis of biological or chemical materials.

A modular multiple use system for precise time and frequency measurement and distribution

NASA Technical Reports Server (NTRS)

Reinhardt, V. S.; Adams, W. S.; Lee, G. M.; Bush, R. L.

1978-01-01

A modular CAMAC based system is described which was developed to meet a variety of precise time and frequency measurement and distribution needs. The system was based on a generalization of the dual mixer concept. By using a 16 channel 100 ns event clock, the system can intercompare the phase of 16 frequency standards with subpicosecond resolution. The system has a noise floor of 26 fs and a long term stability on the order of 1 ps or better. The system also used a digitally controlled crystal oscillator in a control loop to provide an offsettable 5 MHz output with subpicosecond phase tracking capability. A detailed description of the system is given including theory of operation and performance. A method to improve the performance of the dual mixer technique is discussed when phase balancing of the two input ports cannot be accomplished.

Combined Numerical/Analytical Perturbation Solutions of the Navier-Stokes Equations for Aerodynamic (Ejector Nozzle) Flows

NASA Technical Reports Server (NTRS)

DeChant, Lawrence J.

1997-01-01

In spite of the rapid advances in both scalar and parallel computational tools, the large number and breadth of variables involved in aerodynamic systems make the use of parabolized or even boundary layer fluid flow models impractical for both preliminary design and inverse design problems. Given this restriction, we have concluded that reduced or approximate models are an important family of tools for design purposes. This study of a combined perturbation/numerical modeling methodology with an application to ejector-mixer nozzles (shown schematically in the following figure) is nearing completion. The work is being funded by a grant from the NASA Lewis Research Center to Texas A&M University. These ejector-mixer nozzle models are designed to be of use to the High Speed Civil Transport Program and may be adopted by both NASA and industry. A computer code incorporating the ejector-mixer models is under development. This code, the Differential Reduced Ejector/Mixer Analysis (DREA), can be run fast enough to be used as a subroutine or to be called by a design optimization routine. Simplified conservation equations--x-momentum, energy, and mass conservation--are used to define the model. Unlike other preliminary design models, DREA requires minimal empirical input and includes vortical mixing and a fully compressible formulation among other features. DREA is being validated by comparing it with results obtained from open literature and proprietary industry data. Preliminary results for a subsonic ejector and a supersonic ejector are shown. In addition, dedicated experiments have been performed at Texas A&M. These experiments use a hydraulic/gas flow analog to provide information about the inviscid mixing interface structure. Final validation and documentation of this work is expected by May of 1997. However, preliminary versions of DREA can be expected in early 1997. In summary, DREA provides a sufficiently detailed and realistic ejector-mixer nozzle model at a computational cost compatible with preliminary design applications.

Symmetric Gain Optoelectronic Mixers for LADAR

DTIC Science & Technology

2008-12-01

photodetector in the receiver is used as an optoelectronic mixer (OEM). Adding gain to the optoelectronic mixer allows the following transimpedance ...output is the low frequency difference signal, several orders of magnitude lower than the LO signal. Therefore, the gain of the transimpedance ... amplifier (TZA) following the photodetector can be increased, improving LADAR range. The metal-semiconductor- metal (MSM) Schottky detector is such a

Dupoly process for treatment of depleted uranium and production of beneficial end products

DOEpatents

Kalb, Paul D.; Adams, Jay W.; Lageraaen, Paul R.; Cooley, Carl R.

2000-02-29

The present invention provides a process of encapsulating depleted uranium by forming a homogenous mixture of depleted uranium and molten virgin or recycled thermoplastic polymer into desired shapes. Separate streams of depleted uranium and virgin or recycled thermoplastic polymer are simultaneously subjected to heating and mixing conditions. The heating and mixing conditions are provided by a thermokinetic mixer, continuous mixer or an extruder and preferably by a thermokinetic mixer or continuous mixer followed by an extruder. The resulting DUPoly shapes can be molded into radiation shielding material or can be used as counter weights for use in airplanes, helicopters, ships, missiles, armor or projectiles.

Methodology for calculating power consumption of planetary mixers

NASA Astrophysics Data System (ADS)

Antsiferov, S. I.; Voronov, V. P.; Evtushenko, E. I.; Yakovlev, E. A.

2018-03-01

The paper presents the methodology and equations for calculating the power consumption necessary to overcome the resistance of a dry mixture caused by the movement of cylindrical rods in the body of a planetary mixer, as well as the calculation of the power consumed by idling mixers of this type. The equations take into account the size and physico-mechanical properties of mixing material, the size and shape of the mixer's working elements and the kinematics of its movement. The dependence of the power consumption on the angle of rotation in the plane perpendicular to the axis of rotation of the working member is presented.

Integrated Microreactor for Chemical and Biochemical Applications

NASA Technical Reports Server (NTRS)

Schwesinger, N.; Dressler, L.; Frank, Th.; Wurmus, H.

1995-01-01

A completely integrated microreactor was developed that allows for the processing of very small amounts of chemical solutions. The entire system comprises several pumps and valves arranged in different branches as well as a mixing unit and a reaction chamber. The streaming path of each branch contains two valves and one pump each. The pumps are driven by piezoelectric elements mounted on thin glass membranes. Each pump is about 3.5 mm x 3.5 mm x 0.7 mm. A pumping rate up to 25 microliters per hour can be achieved. The operational voltage ranges between 40 and 200 V. A volume stroke up to 1.5 millimeter is achievable from the membrane structures. The valves are designed as passive valves. Sealing is by thin metal films. The dimension of a valve unit is 0.8 x 0.8. 07 mm. The ends of the separate streaming branches are arranged to meet in one point. This point acts as the beginning of a mixer unit which contains several fork-shaped channels. The arrangement of these channels allows for the division of the whole liquid stream into partial streams and their reuniting. A homogeneous mixing of solutions and/or gases can be observed after having passed about 10 of the fork elements. A reaction chamber is arranged behind the mixing unit to support the chemical reaction of special fluids. This unit contains heating elements placed outside of the chamber. The complete system is arranged in a modular structure and is built up of silicon. It comprises three silicon wafers bonded together by applying the silicon direct bonding technology. The silicon structures are made only by wet chemical etching processes. The fluid connections to the outside are realized using standard injection needles glued into v-shaped structures on the silicon wafers. It is possible to integrate other components, like sensors or electronic circuits using silicon as the basic material.

Characterization of MgB2 Superconducting Hot Electron Bolometers

NASA Technical Reports Server (NTRS)

Cunnane, D.; Kawamura, J. H.; Wolak, M. A.; Acharya, N.; Tan, T.; Xi, X. X.; Karasik, B. S.

2014-01-01

Hot-Electron Bolometer (HEB) mixers have proven to be the best tool for high-resolution spectroscopy at the Terahertz frequencies. However, the current state of the art NbN mixers suffer from a small intermediate frequency (IF) bandwidth as well as a low operating temperature. MgB2 is a promising material for HEB mixer technology in view of its high critical temperature and fast thermal relaxation allowing for a large IF bandwidth. In this work, we have fabricated and characterized thin-film (approximately 15 nanometers) MgB2-based spiral antenna-coupled HEB mixers on SiC substrate. We achieved the IF bandwidth greater than 8 gigahertz at 25 degrees Kelvin and the device noise temperature less than 4000 degrees Kelvin at 9 degrees Kelvin using a 600 gigahertz source. Using temperature dependencies of the radiation power dissipated in the device we have identified the optical loss in the integrated microantenna responsible as a cause of the limited sensitivity of the current mixer devices. From the analysis of the current-voltage (IV) characteristics, we have derived the effective thermal conductance of the mixer device and estimated the required local oscillator power in an optimized device to be approximately 1 microwatts.

Low-noise SIS mixer for far-infrared radio astronomy

NASA Astrophysics Data System (ADS)

Karpov, Alexandre; Miller, David; Rice, Frank R.; Stern, Jeffrey A.; Bumble, Bruce; LeDuc, Henry G.; Zmuidzinas, Jonas

2004-10-01

We present a low noise SIS mixer developed for the 1.2 THz band of the heterodyne spectrometer of the Herschel Space Observatory. With the launch of the Herschel SO in 2007, this device will be among the first SIS mixers flown in space. This SIS mixer has a quasi-optical design, with a double slot planar antenna and an extended spherical lens made of pure Si. The SIS junctions are Nb/AlN/NbTiN with a critical current density of about 30 KA/cm2 and with the junction area of a quarter of a micron square. Our mixer circuit uses two SIS junctions biased in parallel. To improve the simultaneous suppression of the Josephson current in each of them, we use diamond-shaped junctions. A low loss Nb/Au micro-strip transmission line is used for the first time in the mixer circuit well above the gap frequency of Nb. The minimum uncorrected Double Sideband receiver noise is 550 K (Y=1.34). The minimum receiver noise corrected for the local oscillator beam splitter and for the cryostat window is 340 K, about 6 hv/k, the lowest value achieved thus far in the THz frequencies range.

A Low Power 2.4 GHz CMOS Mixer Using Forward Body Bias Technique for Wireless Sensor Network

NASA Astrophysics Data System (ADS)

Yin, C. J.; Murad, S. A. Z.; Harun, A.; Ramli, M. M.; Zulkifli, T. Z. A.; Karim, J.

2018-03-01

Wireless sensor network (WSN) is a highly-demanded application since the evolution of wireless generation which is often used in recent communication technology. A radio frequency (RF) transceiver in WSN should have a low power consumption to support long operating times of mobile devices. A down-conversion mixer is responsible for frequency translation in a receiver. By operating a down-conversion mixer at a low supply voltage, the power consumed by WSN receiver can be greatly reduced. This paper presents a development of low power CMOS mixer using forward body bias technique for wireless sensor network. The proposed mixer is implemented using CMOS 0.13 μm Silterra technology. The forward body bias technique is adopted to obtain low power consumption. The simulation results indicate that a low power consumption of 0.91 mW is achieved at 1.6 V supply voltage. Moreover, the conversion gain (CG) of 21.83 dB, the noise figure (NF) of 16.51 dB and the input-referred third-order intercept point (IIP3) of 8.0 dB at 2.4 GHz are obtained. The proposed mixer is suitable for wireless sensor network.

Formation and Fluorimetric Characterization of Micelles in a Micro-flow Through System with Static Micro Mixer

PubMed Central

Schuch, Michael; Gross, G. Alexander; Köhler, J. Michael

2007-01-01

The formation and behaviour of micelles of sodium dodecylsulfate in water by use of a static micro mixer were studied. Trisbipyridylruthenium(II) was applied as indicator dye, 9-methylanthracene was used for fluorescence quenching. All experiments were carried out by a micro fluid arrangement with three syringe pumps, a 2+1 two-step static micro mixer (IPHT Jena) and a on-line micro fluorimetry including a luminescence diode for excitation, a blue glass filter (BG 7, Linos), two edge filters (RG 630, Linos) and a photo counting module (MP 900, Perkin Elmer). It was possible to measure the fluorescence inside the PTFE tube (inner diameter 0.5 mm) directly. A linear dependence of fluorescence intensity from dye concentration was observed in absence of quencher and surfactant as expected. An aggregation number of about 62 was found in the flow rate range between 300 and 800 μL/min. The fluorescence intensity increases slightly, but significant with increasing flow rate, if no quencher is present. In the presence of quencher, the fluorescence intensity decreases with decreasing surfactant concentration and with enhanced flow rate. The strength of the flow rate effect on the fluorescence increases with decreasing surfactant concentration. The size of micelles was determined in micro channels by the micro fluorimetric method in analogy to the conventional system. The micelles extract the quencher from the solution and lower, this way, the quenching effect. The size of micelles was estimated and it could be shown, that the flow rate has only low effect on the aggregation number at the investigated flow rates. The effect of flow rate and surfactant concentration on the fluorescence in the presence of quencher was interpreted as a shift in the micelle concentration due to the shear forces. It is expected, that the fluorescence intensity is lowered, if more quencher molecules are molecular disperse distributed inside the solution. Obviously, the lowered fluorescence intensity at higher flow rates suggests a reduction of the micelle density causing an increase of quencher concentration outside the micelles. PMID:28903241

Convex Grooves in Staggered Herringbone Mixer Improve Mixing Efficiency of Laminar Flow in Microchannel.

PubMed

Kwak, Tae Joon; Nam, Young Gyu; Najera, Maria Alejandra; Lee, Sang Woo; Strickler, J Rudi; Chang, Woo-Jin

2016-01-01

The liquid streams in a microchannel are hardly mixed to form laminar flow, and the mixing issue is well described by a low Reynolds number scheme. The staggered herringbone mixer (SHM) using repeated patterns of grooves in the microchannel have been proved to be an efficient passive micro-mixer. However, only a negative pattern of the staggered herringbone mixer has been used so far after it was first suggested, to the best of our knowledge. In this study, the mixing efficiencies from negative and positive staggered herringbone mixer patterns as well as from opposite flow directions were tested to investigate the effect of the micro-structure geometry on the surrounding laminar flow. The positive herringbone pattern showed better mixing efficiency than the conventionally used negative pattern. Also, generally used forward flow gives better mixing efficiency than reverse flow. The mixing was completed after two cycles of staggered herringbone mixer with both forward and reverse flow in a positive pattern. The traditional negative pattern showed complete mixing after four and five cycles in forward and reverse flow direction, respectively. The mixing effect in all geometries was numerically simulated, and the results confirmed more efficient mixing in the positive pattern than the negative. The results can further enable the design of a more efficient microfluidic mixer, as well as in depth understanding of the phenomena of positive and negative patterns existing in nature with regards to the surrounding fluids.

Convex Grooves in Staggered Herringbone Mixer Improve Mixing Efficiency of Laminar Flow in Microchannel

PubMed Central

Nam, Young Gyu; Najera, Maria Alejandra; Lee, Sang Woo; Strickler, J. Rudi; Chang, Woo-Jin

2016-01-01

The liquid streams in a microchannel are hardly mixed to form laminar flow, and the mixing issue is well described by a low Reynolds number scheme. The staggered herringbone mixer (SHM) using repeated patterns of grooves in the microchannel have been proved to be an efficient passive micro-mixer. However, only a negative pattern of the staggered herringbone mixer has been used so far after it was first suggested, to the best of our knowledge. In this study, the mixing efficiencies from negative and positive staggered herringbone mixer patterns as well as from opposite flow directions were tested to investigate the effect of the micro-structure geometry on the surrounding laminar flow. The positive herringbone pattern showed better mixing efficiency than the conventionally used negative pattern. Also, generally used forward flow gives better mixing efficiency than reverse flow. The mixing was completed after two cycles of staggered herringbone mixer with both forward and reverse flow in a positive pattern. The traditional negative pattern showed complete mixing after four and five cycles in forward and reverse flow direction, respectively. The mixing effect in all geometries was numerically simulated, and the results confirmed more efficient mixing in the positive pattern than the negative. The results can further enable the design of a more efficient microfluidic mixer, as well as in depth understanding of the phenomena of positive and negative patterns existing in nature with regards to the surrounding fluids. PMID:27814386

An easily fabricated three-dimensional threaded lemniscate-shaped micromixer for a wide range of flow rates

PubMed Central

Rafeie, Mehdi; Welleweerd, Marcel; Hassanzadeh-Barforoushi, Amin; Asadnia, Mohsen; Olthuis, Wouter; Ebrahimi Warkiani, Majid

2017-01-01

Mixing fluid samples or reactants is a paramount function in the fields of micro total analysis system (μTAS) and microchemical processing. However, rapid and efficient fluid mixing is difficult to achieve inside microchannels because of the difficulty of diffusive mass transfer in the laminar regime of the typical microfluidic flows. It has been well recorded that the mixing efficiency can be boosted by migrating from two-dimensional (2D) to three-dimensional (3D) geometries. Although several 3D chaotic mixers have been designed, most of them offer a high mixing efficiency only in a very limited range of Reynolds numbers (Re). In this work, we developed a 3D fine-threaded lemniscate-shaped micromixer whose maximum numerical and empirical efficiency is around 97% and 93%, respectively, and maintains its high performance (i.e., >90%) over a wide range of 1 < Re < 1000 which meets the requirements of both the μTAS and microchemical process applications. The 3D micromixer was designed based on two distinct mixing strategies, namely, the inducing of chaotic advection by the presence of Dean flow and diffusive mixing through thread-like grooves around the curved body of the mixers. First, a set of numerical simulations was performed to study the physics of the flow and to determine the essential geometrical parameters of the mixers. Second, a simple and cost-effective method was exploited to fabricate the convoluted structure of the micromixers through the removal of a 3D-printed wax structure from a block of cured polydimethylsiloxane. Finally, the fabricated mixers with different threads were tested using a fluorescent microscope demonstrating a good agreement with the results of the numerical simulation. We envisage that the strategy used in this work would expand the scope of the micromixer technology by broadening the range of efficient working flow rate and providing an easy way to the fabrication of 3D convoluted microstructures. PMID:28798843

An easily fabricated three-dimensional threaded lemniscate-shaped micromixer for a wide range of flow rates.

PubMed

Rafeie, Mehdi; Welleweerd, Marcel; Hassanzadeh-Barforoushi, Amin; Asadnia, Mohsen; Olthuis, Wouter; Ebrahimi Warkiani, Majid

2017-01-01

Mixing fluid samples or reactants is a paramount function in the fields of micro total analysis system (μTAS) and microchemical processing. However, rapid and efficient fluid mixing is difficult to achieve inside microchannels because of the difficulty of diffusive mass transfer in the laminar regime of the typical microfluidic flows. It has been well recorded that the mixing efficiency can be boosted by migrating from two-dimensional (2D) to three-dimensional (3D) geometries. Although several 3D chaotic mixers have been designed, most of them offer a high mixing efficiency only in a very limited range of Reynolds numbers ( Re ). In this work, we developed a 3D fine-threaded lemniscate-shaped micromixer whose maximum numerical and empirical efficiency is around 97% and 93%, respectively, and maintains its high performance (i.e., >90%) over a wide range of 1 <  Re  < 1000 which meets the requirements of both the μTAS and microchemical process applications. The 3D micromixer was designed based on two distinct mixing strategies, namely, the inducing of chaotic advection by the presence of Dean flow and diffusive mixing through thread-like grooves around the curved body of the mixers. First, a set of numerical simulations was performed to study the physics of the flow and to determine the essential geometrical parameters of the mixers. Second, a simple and cost-effective method was exploited to fabricate the convoluted structure of the micromixers through the removal of a 3D-printed wax structure from a block of cured polydimethylsiloxane. Finally, the fabricated mixers with different threads were tested using a fluorescent microscope demonstrating a good agreement with the results of the numerical simulation. We envisage that the strategy used in this work would expand the scope of the micromixer technology by broadening the range of efficient working flow rate and providing an easy way to the fabrication of 3D convoluted microstructures.

Liquid chromatography coupled to on-line post column derivatization for the determination of organic compounds: a review on instrumentation and chemistries.

PubMed

Zacharis, Constantinos K; Tzanavaras, Paraskevas D

2013-10-10

Analytical derivatization either in pre or post column modes is one of the most widely used sample pretreatment techniques coupled to liquid chromatography. In the present review article we selected to discuss the post column derivatization mode for the analysis of organic compounds. The first part of the review focuses to the instrumentation of post-column setups including not only fundamental components such as pumps and reactors but also less common parts such as static mixers and back-pressure regulators; the second part of the article discusses the most popular "chemistries" that are involved in post column applications, including reagent-less approaches and new sensing platforms such as the popular gold nanoparticles. Some representative recent applications are also presented as tables. Copyright © 2013 Elsevier B.V. All rights reserved.

Low NO(x) Combustor Development

NASA Technical Reports Server (NTRS)

Kastl, J. A.; Herberling, P. V.; Matulaitis, J. M.

2005-01-01

The goal of these efforts was the development of an ultra-low emissions, lean-burn combustor for the High Speed Civil Transport. The HSCT Mach 2.4 FLADE C1 Cycle was selected as the baseline engine cycle. A preliminary compilation of performance requirements for the HSCT combustor system was developed. The emissions goals of the program, baseline engine cycle, and standard combustor performance requirements were considered in developing the compilation of performance requirements. Seven combustor system designs were developed. The development of these system designs was facilitated by the use of spreadsheet-type models which predicted performance of the combustor systems over the entire flight envelope of the HSCT. A chemical kinetic model was developed for an LPP combustor and employed to study NO(x) formation kinetics, and CO burnout. These predictions helped to define the combustor residence time. Five fuel-air mixer concepts were analyzed for use in the combustor system designs. One of the seven system designs, one using the Swirl-Jet and Cyclone Swirler fuel-air mixers, was selected for a preliminary mechanical design study.

A quasi-optical flight mixer. [Schottky diodes and wire grid lenses

NASA Technical Reports Server (NTRS)

1978-01-01

A mechanically stable single block mixer design is described utilizing a recessed whisker and beamwidth equalization lens. A stripline I.F. matching section which is an integral part of the mixer is presented. Engineering measurements of wire grids and dielectric transmission loss near one millimeter wavelength are given and an anomolous I-V curve behavior observed during diode whiskering is discussed.

Numerical analysis on a passive chaotic micromixer with helical microchannel.

PubMed

Wang, Ruijin; Lin, Jianzhong

2006-01-01

In order to improve the mixing efficiency, the diffusion and mixing of species in the helical micro-mixer are simulated numerically. The results show that the mixing efficiency in the helical micromixer is much higher than that in the straight micro-channel and obviously higher than that in the serpentine micro-channel when Reynolds number is low. At high Reynolds number, even though the mixing efficiency in the helical micro-mixer is still much higher than that in the straight micro-channel, no obvious difference of mixing efficiency in the helical micro-mixer and serpentine micro-channel is found. The conclusions are helpful to optimize the structure of the micro-mixer.

670 GHz Schottky Diode Based Subharmonic Mixer with CPW Circuits and 70 GHz IF

NASA Technical Reports Server (NTRS)

Chattopadhyay, Goutam (Inventor); Schlecht, Erich T. (Inventor); Lee, Choonsup (Inventor); Lin, Robert H. (Inventor); Gill, John J. (Inventor); Sin, Seth (Inventor); Mehdi, Imran (Inventor)

2014-01-01

A coplanar waveguide (CPW) based subharmonic mixer working at 670 GHz using GaAs Schottky diodes. One example of the mixer has a LO input, an RF input and an IF output. Another possible mixer has a LO input, and IF input and an RF output. Each input or output is connected to a coplanar waveguide with a matching network. A pair of antiparallel diodes provides a signal at twice the LO frequency, which is then mixed with a second signal to provide signals having sum and difference frequencies. The output signal of interest is received after passing through a bandpass filter tuned to the frequency range of interest.

DUPoly process for treatment of depleted uranium and production of beneficial end products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalb, P.D.; Adams, J.W.; Lageraaen, P.R.

2000-02-29

The present invention provides a process of encapsulating depleted uranium by forming a homogeneous mixture of depleted uranium and molten virgin or recycled thermoplastic polymer into desired shapes. Separate streams of depleted uranium and virgin or recycled thermoplastic polymer are simultaneously subjected to heating and mixing conditions. The heating and mixing conditions are provided by a thermokinetic mixer, continuous mixer or an extruder and preferably by a thermokinetic mixer or continuous mixer followed by an extruder. The resulting DUPoly shapes can be molded into radiation shielding material or can be used as counter weights for use in airplanes, helicopters, ships,more » missiles, armor or projectiles.« less

Focal plane arrays for submillimeter waves using two-dimensional electron gas elements: A grant under the Innovative Research Program

NASA Technical Reports Server (NTRS)

Yngvesson, K. Sigfrid; Lau, Kei-May

1992-01-01

This final report describes a three-year research effort, aimed at developing new types of THz low noise receivers, based on bulk effect ('hot electron') nonlinearities in the Two-Dimensional Electron Gas (2DEG) Medium, and the inclusion of such receivers in focal plane arrays. 2DEG hot electron mixers have been demonstrated at 35 and 94 GHz with three orders of magnitude wider bandwidth than previous hot electron mixers, which use bulk InSb. The 2DEG mixers employ a new mode of operation, which was invented during this program. Only moderate cooling is required for this mode, to temperatures in the range 20-77 K. Based on the results of this research, it is now possible to design a hot electron mixer focal plane array for the THz range, which is anticipated to have a DSB receiver noise temperature of 500-1000K. In our work on this grant, we have found similar results the the Cronin group (resident at the University of Bath, UK). Neither group has so far demonstrated heterodyne detection in this mode, however. We discovered and explored some new effects in the magnetic field mode, and these are described in the report. In particular, detection of 94 GHz and 238 GHz, respectively, by a new effect, 'Shubnikov de Haas detection', was found to be considerably stronger in our materials than the cyclotron resonance detection. All experiments utilized devices with an active 2DEG region of size of the order of 10-40 micrometers long, and 20-200 micrometers wide, formed at the heterojunction between AlGaAs and GaAs. All device fabrication was performed in-house. The materials for the devices were also grown in-house, utilizing OMCVD (Organo Metallic Chemical Vapor Deposition). In the course of this grant, we developed new techniques for growing AlGaAs/GaAs with mobilities equalling the highest values published by any laboratory. We believe that the field of hot electron mixers and detectors will grow substantially in importance in the next few years, partly as a result of the opportunity given us through this grant, which represents the major effort in the US so far. We note, however, that parallel research on hot electron mixers in thin film superconductors in Russia, and recently in Sweden, have demonstrated mixing up to 1 THz, with the potential for low-noise receivers for frequencies up to many THz. The three groups recently assessed the relative adtantages of 2DEG and superconducting film mixers in a joint paper (Kollberg et al., 1992; see Appendix II).

Focal plane arrays for submillimeter waves using two-dimensional electron gas elements: A grant under the Innovative Research Program

NASA Astrophysics Data System (ADS)

Yngvesson, K. Sigfrid; Lau, Kei-May

1992-02-01

This final report describes a three-year research effort, aimed at developing new types of THz low noise receivers, based on bulk effect ('hot electron') nonlinearities in the Two-Dimensional Electron Gas (2DEG) Medium, and the inclusion of such receivers in focal plane arrays. 2DEG hot electron mixers have been demonstrated at 35 and 94 GHz with three orders of magnitude wider bandwidth than previous hot electron mixers, which use bulk InSb. The 2DEG mixers employ a new mode of operation, which was invented during this program. Only moderate cooling is required for this mode, to temperatures in the range 20-77 K. Based on the results of this research, it is now possible to design a hot electron mixer focal plane array for the THz range, which is anticipated to have a DSB receiver noise temperature of 500-1000K. In our work on this grant, we have found similar results the the Cronin group (resident at the University of Bath, UK). Neither group has so far demonstrated heterodyne detection in this mode, however. We discovered and explored some new effects in the magnetic field mode, and these are described in the report. In particular, detection of 94 GHz and 238 GHz, respectively, by a new effect, 'Shubnikov de Haas detection', was found to be considerably stronger in our materials than the cyclotron resonance detection. All experiments utilized devices with an active 2DEG region of size of the order of 10-40 micrometers long, and 20-200 micrometers wide, formed at the heterojunction between AlGaAs and GaAs. All device fabrication was performed in-house. The materials for the devices were also grown in-house, utilizing OMCVD (Organo Metallic Chemical Vapor Deposition). In the course of this grant, we developed new techniques for growing AlGaAs/GaAs with mobilities equalling the highest values published by any laboratory. We believe that the field of hot electron mixers and detectors will grow substantially in importance in the next few years, partly as a result of the opportunity given us through this grant, which represents the major effort in the US so far. We note, however, that parallel research on hot electron mixers in thin film superconductors in Russia, and recently in Sweden, have demonstrated mixing up to 1 THz, with the potential for low-noise receivers for frequencies up to many THz. The three groups recently assessed the relative adtantages of 2DEG and superconducting film mixers in a joint paper (Kollberg et al., 1992; see Appendix II).

Wide-bandwidth electron bolometric mixers - A 2DEG prototype and potential for low-noise THz receivers

NASA Technical Reports Server (NTRS)

Yang, Jian-Xun; Agahi, Farid; Dai, Dong; Musante, Charles F.; Grammer, Wes; Lau, Kei M.; Yngvesson, K. S.

1993-01-01

This paper presents a new type of electron bolometric ('hot electron') mixer. We have demonstrated a 3 order-of-magnitude improvement in the bandwidth compared with previously known types of electron bolometric mixers, by using the two-dimensional electron gas (2DEG) medium at the heterointerface between AlGaAs and GaAs. We have tested both in-house MOCVD-grown material and MBE material, with similar results. The conversion loss (Lc) at 94 GHz is presently 18 dB for a mixer operating at 20 K, and calculations indicate that Lc can be decreased to about 10 dB in future devices. Calculated and measured curves of Lc versus P(LO), and I(DC), respectively, agree well. We argue that there are several different configurations of electron bolometric mixers, which will all show wide bandwidth, and that these devices are likely to become important as low-noise THz receivers in the future.

Biasable, Balanced, Fundamental Submillimeter Monolithic Membrane Mixer

NASA Technical Reports Server (NTRS)

Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Gill, John; Velebir, James; Tsang, Raymond; Dengler, Robert; Lin, Robert

2010-01-01

This device is a biasable, submillimeter-wave, balanced mixer fabricated using JPL s monolithic membrane process a simplified version of planar membrane technology. The primary target application is instrumentation used for analysis of atmospheric constituents, pressure, temperature, winds, and other physical and chemical properties of the atmospheres of planets and comets. Other applications include high-sensitivity gas detection and analysis. This innovation uses a balanced configuration of two diodes allowing the radio frequency (RF) signal and local oscillator (LO) inputs to be separated. This removes the need for external diplexers that are inherently narrowband, bulky, and require mechanical tuning to change frequency. Additionally, this mixer uses DC bias-ability to improve its performance and versatility. In order to solve problems relating to circuit size, the GaAs membrane process was created. As much of the circuitry as possible is fabricated on-chip, making the circuit monolithic. The remainder of the circuitry is precision-machined into a waveguide block that holds the GaAs circuit. The most critical alignments are performed using micron-scale semiconductor technology, enabling wide bandwidth and high operating frequencies. The balanced mixer gets superior performance with less than 2 mW of LO power. This can be provided by a simple two-stage multiplier chain following an amplifier at around 90 GHz. Further, the diodes are arranged so that they can be biased. Biasing pushes the diodes closer to their switching voltage, so that less LO power is required to switch the diodes on and off. In the photo, the diodes are at the right end of the circuit. The LO comes from the waveguide at the right into a reduced-height section containing the diodes. Because the diodes are in series to the LO signal, they are both turned on and off simultaneously once per LO cycle. Conversely, the RF signal is picked up from the RF waveguide by the probe at the left, and flows rightward to the diodes. Because the RF is in a quasi- TEM (suspended, microstrip-like) mode, it impinges on the diodes in an anti-parallel mode that does not couple to the waveguide mode. This isolates the LO and RF signals. This operation is similar to a cross-bar mixer used at low frequencies, except the RF signal enters through the back-short end of the waveguide rather than through the side. The RF probe also conveys the down-converted intermediate frequency (IF) signal out to an off-chip circuit board through a simple LC low-pass filter to the left as indicated. The bias is brought to the diodes through a bypass capacitor at the top.

Liquid Oxygen Thermodynamic Vent System Testing with Helium Pressurization

NASA Technical Reports Server (NTRS)

VanDresar, Neil T.

2014-01-01

This report presents the results of several thermodynamic vent system (TVS) tests with liquid oxygen plus a test with liquid nitrogen. In all tests, the liquid was heated above its normal boiling point to 111 K for oxygen and 100 K for nitrogen. The elevated temperature was representative of tank conditions for a candidate lunar lander ascent stage. An initial test series was conducted with saturated oxygen liquid and vapor at 0.6 MPa. The initial series was followed by tests where the test tank was pressurized with gaseous helium to 1.4 to 1.6 MPa. For these tests, the helium mole fraction in the ullage was quite high, about 0.57 to 0.62. TVS behavior is different when helium is present than when helium is absent. The tank pressure becomes the sum of the vapor pressure and the partial pressure of helium. Therefore, tank pressure depends not only on temperature, as is the case for a pure liquid-vapor system, but also on helium density (i.e., the mass of helium divided by the ullage volume). Thus, properly controlling TVS operation is more challenging with helium pressurization than without helium pressurization. When helium was present, the liquid temperature would rise with each successive TVS cycle if tank pressure was kept within a constant control band. Alternatively, if the liquid temperature was maintained within a constant TVS control band, the tank pressure would drop with each TVS cycle. The final test series, which was conducted with liquid nitrogen pressurized with helium, demonstrated simultaneous pressure and temperature control during TVS operation. The simultaneous control was achieved by systematic injection of additional helium during each TVS cycle. Adding helium maintained the helium partial pressure as the liquid volume decreased because of TVS operation. The TVS demonstrations with liquid oxygen pressurized with helium were conducted with three different fluid-mixer configurations-a submerged axial jet mixer, a pair of spray hoops in the tank ullage, and combined use of the axial jet and spray hoops. A submerged liquid pump and compact heat exchanger located inside the test tank were used with all the mixer configurations. The initial series without helium and the final series with liquid nitrogen both used the axial jet mixer. The axial jet configuration successfully demonstrated the ability to control tank pressure; but in the normal-gravity environment, the temperature in the upper tank region (ullage and unwetted wall) was not controlled. The spray hoops and axial jet combination also successfully demonstrated pressure control as well as temperature control of the entire tank and contents. The spray-hoops-only configuration was not expected to be a reliable means of tank mixing because there was no direct means to produce liquid circulation. However, surprisingly good results also were obtained with the sprayhoops- only configuration (i.e., performance metrics such as cycle-averaged vent flowrate were similar to those obtained with the other configurations). A simple thermodynamic model was developed that correctly predicted the TVS behavior (temperature rise or pressure drop per TVS cycle) when helium was present in the ullage. The model predictions were correlated over a range of input parameters. The correlations show that temperature rise or pressure drop per cycle was proportional to both helium mole fraction and tank heat input. The response also depended on the tank fill fraction: the temperature rise or pressure drop (per TVS cycle) increased as the ullage volume decreased.

Compact terahertz passive spectrometer with wideband superconductor-insulator-superconductor mixer.

PubMed

Kikuchi, K; Kohjiro, S; Yamada, T; Shimizu, N; Wakatsuki, A

2012-02-01

We developed a compact terahertz (THz) spectrometer with a superconductor-insulator-superconductor (SIS) mixer, aiming to realize a portable and highly sensitive spectrometer to detect dangerous gases at disaster sites. The receiver cryostat which incorporates the SIS mixer and a small cryocooler except for a helium compressor has a weight of 27 kg and dimensions of 200 mm × 270 mm × 690 mm. In spite of the small cooling capacity of the cryocooler, the SIS mixer is successfully cooled lower than 4 K, and the temperature variation is suppressed for the sensitive measurement. By adopting a frequency sweeping system using photonic local oscillator, we demonstrated a spectroscopic measurement of CH(3)CN gas in 0.2-0.5 THz range.

Efficient gas-liquid contact using microfluidic membrane devices with staggered herringbone mixers.

PubMed

Femmer, Tim; Eggersdorfer, Max L; Kuehne, Alexander J C; Wessling, Matthias

2015-08-07

We describe a novel membrane based gas-liquid-contacting device with increased mass transport and reduced pressure loss by combining a membrane with a staggered herringbone static mixer. Herringbone structures are imposed on the microfluidic channel geometry via soft lithography, acting as mixers which introduce secondary flows at the membrane interface. Such flows include Dean vortices and Taylor flows generating effective mixing while improving mass transport and preventing concentration polarization in microfluidic channels. Furthermore, our static herringbone mixer membranes effectively reduce pressure losses leading to devices with enhanced transfer properties for microfluidic gas-liquid contact. We investigate the red blood cell distribution to tailor our devices towards miniaturised extracorporeal membrane oxygenation and improved comfort of patients with lung insufficiencies.

Full-scale altitude engine test of a turbofan exhaust-gas-forced mixer to reduce thrust specific fuel consumption

NASA Technical Reports Server (NTRS)

Cullom, R. R.; Johnson, R. L.

1977-01-01

The specific fuel consumption of a low-bypass-ratio, confluent-flow, turbofan engine was measured with and without a mixer installed. Tests were conducted for flight Mach numbers from 0.3 to 1.4 and altitudes from 10,670 to 14,630 meters (35,000 to 48,000 ft) for core-stream-to-fan-stream temperature ratios of 2.0 and 2.5 and mixing-length-to-diameter ratios of 0.95 and 1.74. For these test conditions, the reduction in specific fuel consumption varied from 2.5 percent to 4.0 percent. Pressure loss measurements as well as temperature and pressure surveys at the mixer inlet, the mixer exit, and the nozzle inlet were made.

Organic Separation Test Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

2014-09-22

Separable organics have been defined as “those organic compounds of very limited solubility in the bulk waste and that can form a separate liquid phase or layer” (Smalley and Nguyen 2013), and result from three main solvent extraction processes: U Plant Uranium Recovery Process, B Plant Waste Fractionation Process, and Plutonium Uranium Extraction (PUREX) Process. The primary organic solvents associated with tank solids are TBP, D2EHPA, and NPH. There is concern that, while this organic material is bound to the sludge particles as it is stored in the tanks, waste feed delivery activities, specifically transfer pump and mixer pump operations,more » could cause the organics to form a separated layer in the tank farms feed tank. Therefore, Washington River Protection Solutions (WRPS) is experimentally evaluating the potential of organic solvents separating from the tank solids (sludge) during waste feed delivery activities, specifically the waste mixing and transfer processes. Given the Hanford Tank Waste Treatment and Immobilization Plant (WTP) waste acceptance criteria per the Waste Feed Acceptance Criteria document (24590-WTP-RPT-MGT-11-014) that there is to be “no visible layer” of separable organics in the waste feed, this would result in the batch being unacceptable to transfer to WTP. This study is of particular importance to WRPS because of these WTP requirements.« less

8-beam local oscillator array at 47 THz generated by a phase grating and a quantum cascade laser

DOE PAGES

Mirzaei, B.; Silva, J. R. G.; Hayton, D.; ...

2017-11-13

We present an 8-beam local oscillator (LO) for the astronomically significant [OI] line at 4.7 THz. The beams are generated using a quantum cascade laser (QCL) in combination with a Fourier phase grating. The grating is fully characterized using a third order distributed feedback (DFB) QCL with a single mode emission at 4.7 THz as the input. The measured diffraction efficiency of 74.3% is in an excellent agreement with the calculated result of 75.4% using a 3D simulation. We show that the power distribution among the diffracted beams is uniform enough for pumping an array receiver. To validate the gratingmore » bandwidth, we apply a far-infrared (FIR) gas laser emission at 5.3 THz as the input and find a very similar performance in terms of efficiency, power distribution, and spatial configuration of the diffracted beams. Both results represent the highest operating frequencies of THz phase gratings reported in the literature. By injecting one of the eight diffracted 4.7 THz beams into a superconducting hot electron bolometer (HEB) mixer, we find that the coupled power, taking the optical loss into account, is in consistency with the QCL power value.« less

Low-cost fabrication and performance testing of Polydimethylsiloxane (PDMS) micromixers using an improved print-and-Peel (PAP) method

NASA Astrophysics Data System (ADS)

Abagon, Ma. Victoria; Buendia, Neil Daniel; Jasper Caracas, Corine; July Yap, Kristian

2018-03-01

The research presents different configurations of microfluidic mixers made from polydimethylsiloxane (PDMS) fabricated using an improved, low-cost print-and-peel (PAP) method. Processes, such as mixing, operated in the micro scale allow decreased equipment size-to-production capacity ratio and decreased energy consumption per unit product. In the study, saturated solutions of blue and yellow food dyes were introduced inside the channels using a LEGO® improvised microsyringe pump. Scanning Electron Microscopy (SEM) was used to determine the average depth of the fabricated micromixers which was found to be around 14 ¼m. The flows were observed and images were taken using a light microscope. The color intensities of the images were then measured using MATLAB®. From the relationship between color intensity and concentration, the mixing indices were calculated and found to be 0.9435 to 0.9941, which falls within the standard mixing index range (0.8 - 1.0) regardless of the flow rate and the configuration of the micromixer as verified through the two-way ANOVA. From the cost analysis, the cost of the device fabricated in this study is a hundred-fold less than expenses from standard fabrication procedures. Hence, the fabricated device provides an alternative for micromixers produced from expensive and conventional lithographic methods.

Systematic analysis of CMOS-micromachined inductors with application to mixer matching circuits

NASA Astrophysics Data System (ADS)

Wu, Jerry Chun-Li

The growing demand for consumer voice and data communication systems and military communication applications has created a need for low-power, low-cost, high-performance radio-frequency (RF) front-end. To achieve this goal, bringing passive components, especially inductors, to silicon is imperative. On-chip passive components such as inductors and capacitors generally enhance the reliability and efficiency of silicon-integrated RF cells. They can provide circuit solutions with superior performance and contribute to a higher level of integration. With passive components on chip, there is a great opportunity to have transformers, filters, and matching networks on chip. However, inductors on silicon have a low quality factor (Q) due to both substrate and metal loss. This dissertation demonstrates the systematic analysis of inductors fabricated using standard complementary metal-oxide-semiconductor (CMOS) and micro-electro-mechanical (MEMS) system technologies. We report system-on-chip inductor modeling, simulation, and measurements of effective inductance and quality factors. In this analysis methodology, a number of systematic simulations are performed on regular and micromachined inductors with different parameters such as spiral topology, number of turns, outer diameter, thickness, and percentage of substrate removed by using micromachining technologies. Three different novel support structures of the micromachined spiral inductor are proposed, analyzed, and implemented for larger size suspended inductors. The sensitivity of the structure support and different degree of substrate etching by post-processing is illustrated. The results provide guidelines for the selection of inductor parameters, post-processing methodologies, and its spiral supports to meet the RF design specifications and the stability requirements for mobile communication. The proposed CMOS-micromachined inductor is used in a low cost-effective double-balanced Gilbert mixer with on-chip matching network. The integrated mixer inductor was implemented and tested to prove the concept.

XY vs X Mixer in Quantum Alternating Operator Ansatz for Optimization Problems with Constraints

NASA Technical Reports Server (NTRS)

Wang, Zhihui; Rubin, Nicholas; Rieffel, Eleanor G.

2018-01-01

Quantum Approximate Optimization Algorithm, further generalized as Quantum Alternating Operator Ansatz (QAOA), is a family of algorithms for combinatorial optimization problems. It is a leading candidate to run on emerging universal quantum computers to gain insight into quantum heuristics. In constrained optimization, penalties are often introduced so that the ground state of the cost Hamiltonian encodes the solution (a standard practice in quantum annealing). An alternative is to choose a mixing Hamiltonian such that the constraint corresponds to a constant of motion and the quantum evolution stays in the feasible subspace. Better performance of the algorithm is speculated due to a much smaller search space. We consider problems with a constant Hamming weight as the constraint. We also compare different methods of generating the generalized W-state, which serves as a natural initial state for the Hamming-weight constraint. Using graph-coloring as an example, we compare the performance of using XY model as a mixer that preserves the Hamming weight with the performance of adding a penalty term in the cost Hamiltonian.

Assessment of Integrated Nozzle Performance

NASA Technical Reports Server (NTRS)

Lambert, H. H.; Mizukami, M.

1999-01-01

This presentation highlights the activities that researchers at the NASA Lewis Research Center (LeRC) have been and will be involved in to assess integrated nozzle performance. Three different test activities are discussed. First, the results of the Propulsion Airframe Integration for High Speed Research 1 (PAIHSR1) study are presented. The PAIHSR1 experiment was conducted in the LeRC 9 ft x l5 ft wind tunnel from December 1991 to January 1992. Second, an overview of the proposed Mixer/ejector Inlet Distortion Study (MIDIS-E) is presented. The objective of MIDIS-E is to assess the effects of applying discrete disturbances to the ejector inlet flow on the acoustic and aero-performance of a mixer/ejector nozzle. Finally, an overview of the High-Lift Engine Aero-acoustic Technology (HEAT) test is presented. The HEAT test is a cooperative effort between the propulsion system and high-lift device research communities to assess wing/nozzle integration effects. The experiment is scheduled for FY94 in the NASA Ames Research Center (ARC) 40 ft x 80 ft Low Speed Wind Tunnel (LSWT).

Phased-Array Study of Dual-Flow Jet Noise: Effect of Nozzles and Mixers

NASA Technical Reports Server (NTRS)

Soo Lee, Sang; Bridges, James

2006-01-01

A 16-microphone linear phased-array installed parallel to the jet axis and a 32-microphone azimuthal phased-array installed in the nozzle exit plane have been applied to identify the noise source distributions of nozzle exhaust systems with various internal mixers (lobed and axisymmetric) and nozzles (three different lengths). Measurements of velocity were also obtained using cross-stream stereo particle image velocimetry (PIV). Among the three nozzle lengths tested, the medium length nozzle was the quietest for all mixers at high frequency on the highest speed flow condition. Large differences in source strength distributions between nozzles and mixers occurred at or near the nozzle exit for this flow condition. The beamforming analyses from the azimuthal array for the 12-lobed mixer on the highest flow condition showed that the core flow and the lobe area were strong noise sources for the long and short nozzles. The 12 noisy spots associated with the lobe locations of the 12-lobed mixer with the long nozzle were very well detected for the frequencies 5 KHz and higher. Meanwhile, maps of the source strength of the axisymmetric splitter show that the outer shear layer was the most important noise source at most flow conditions. In general, there was a good correlation between the high turbulence regions from the PIV tests and the high noise source regions from the phased-array measurements.

Acoustic and Laser Doppler Anemometer Results for Confluent, 22-Lobed, and Unique-Lobed Mixer Exhaust Systems for Subsonic Jet Noise Reduction

NASA Technical Reports Server (NTRS)

Salikuddin, M.; Martens, S.; Shin, H.; Majjigi, R. K.; Krejsa, Gene (Technical Monitor)

2002-01-01

The objective of this task was to develop a design methodology and noise reduction concepts for high bypass exhaust systems which could be applied to both existing production and new advanced engine designs. Special emphasis was given to engine cycles with bypass ratios in the range of 4:1 to 7:1, where jet mixing noise was a primary noise source at full power takeoff conditions. The goal of this effort was to develop the design methodology for mixed-flow exhaust systems and other novel noise reduction concepts that would yield 3 EPNdB noise reduction relative to 1992 baseline technology. Two multi-lobed mixers, a 22-lobed axisymmetric and a 21-lobed with a unique lobe, were designed. These mixers along with a confluent mixer were tested with several fan nozzles of different lengths with and without acoustic treatment in GEAE's Cell 41 under the current subtask (Subtask C). In addition to the acoustic and LDA tests for the model mixer exhaust systems, a semi-empirical noise prediction method for mixer exhaust system is developed. Effort was also made to implement flowfield data for noise prediction by utilizing MGB code. In general, this study established an aero and acoustic diagnostic database to calibrate and refine current aero and acoustic prediction tools.

An inductorless active mixer using stacked nMOS/pMOS configuration and LO shaping technique

NASA Astrophysics Data System (ADS)

Guo, Benqing; Chen, Jun; Wang, Xuebing; Chen, Hongpeng

2018-04-01

In this paper, a CMOS active down-conversion mixer is presented for wideband applications. Specifically, a LO generation chain is suggested to convert AC LO signal to shaped trapezoid burst, which reduces the sinusoidal LO power level requirement by the mixer. The current-reuse technique by stacked nMOS/pMOS architecture is used to save the power consumption of the circuit. Moreover, this complementary configuration is also employed to compensate second-order nonlinearity of the circuit. Implemented in a 0.18-μm CMOS process, post-simulations show that, driven by only ‑10 dBm sinusoidal LO signal, the proposed inductorless mixer provides a maximal conversion gain of 15.7 dB and a noise figure (NF) of 9.1-12 dB across RF input frequency range 0.5-1.6 GHz. The IIP3 and IP1dB of 3.5 dBm and ‑4.8 dBm are obtained, respectively. The mixer core only consumes 3.6 mW from a 1.8-V supply.

AlGaAs/GaAs quasi-bulk effect mixers: Analysis and experiments

NASA Technical Reports Server (NTRS)

Yngvesson, K. S.; Yang, J.-X.; Agahi, F.; Dai, D.; Musante, C.; Grammer, W.; Lau, K. M.

1992-01-01

The lowest noise temperature for any receiver in the 0.5 to 1 THz range has been achieved with the bulk InSb hot electron mixer, which unfortunately suffers from the problem of having a very narrow bandwidth (1-2 MHz). We have demonstrated a three order of magnitude improvement in the bandwidth of hot electron mixers, by using the two-dimensional electron gas (2DEG) medium at the hetero-interface between AlGaAs and GaAs. We have tested both inhouse MOCVD-grown material, and MBE materials, with similar results. The conversion loss (L(sub c)) at 94 GHz is presently 18 dB for a mixer operating at 20 K, and calculations indicate that L(sub c) can be decreased to about 10 dB in future devices. Calculated and measured curves of L(sub c), versus PLO and IDC, respectively, agree well. We argue that there are several different configurations of hot electron mixers, which will also show wide bandwidth, and that these devices are likely to become important as low-noise THz receivers in the future.

A low noise 230 GHz heterodyne receiver employing .25 sq micron area Nb/AlO(x)/Nb tunnel junctions

NASA Technical Reports Server (NTRS)

Kooi, Jacob W.; Chan, M.; Phillips, T. G.; Bumble, B.; Leduc, H. G.

1992-01-01

Recent results for a full height rectangular waveguide mixer with an integrated IF matching network are reported. Two 0.25 sq micron Nb/AlO(x)/Nb superconducting insulating superconducting (SIS) tunnel junctions with a current density of about 8500 A/sq cm and omega RC of about 2.5 at 230 GHz have been tested. Detailed measurements of the receiver noise have been made from 200-290 GHz for both junctions at 4.2 K. The lowest receiver noise temperatures were recorded at 239 GHz, measuring 48 K DSB at 4.2 K and 40 K DSB at 2.1 K. The 230 GHz receiver incorporates a one octave wide integrated low pass filter and matching network which transforms the pumped IF junction impedance to 50 ohms over a wide range of impedances.

An In-Port Feeding System for Shipboard Personnel. Volume 3. A personnel, Equipment, and Facility Evaluation of the Enlisted Dining Facilities at NAS North Island and NAVSTA San Diego.

DTIC Science & Technology

1981-05-01

2.13 14.20 - Mixer S.D. 1.05 4.92 - Oven Proofer Range Glazes (bread) X 1.28 3.69 - Range S.D. 1.12 2.91 - Mixer Dough (breed) X 4.53 9.34 - Mixer SS.D...Steamer S.D. 0 - - Tomatoes X 16.00 17.00 - Range S.D. 21.21 12.73 - Steam kettle Fryer Desserts: Cookies X 1.92 10.97 - Range S.D. 1.21 1.85 - Mixer...88.30 Salad Dressing 550 24.07 51.21 Sandwiches 1,100 346.69 307.14 Beverages, cold 550 93.33 88.92 Dessert, cookies 550 15.05 67.19 Totals 550 599.94 lb

On the Application of Inverse-Mode SiGe HBTs in RF Receivers for the Mitigation of Single-Event Transients

NASA Astrophysics Data System (ADS)

Song, Ickhyun; Cho, Moon-Kyu; Oakley, Michael A.; Ildefonso, Adrian; Ju, Inchan; Buchner, Stephen P.; McMorrow, Dale; Paki, Pauline; Cressler, John. D.

2017-05-01

Best practice in mitigation strategies for single-event transients (SETs) in radio-frequency (RF) receiver modules is investigated using a variety of integrated receivers utilizing inverse-mode silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs). The receivers were designed and implemented in a 130-nm SiGe BiCMOS technology platform. In general, RF switches, low-noise amplifiers (LNAs), and downconversion mixers utilizing inverse-mode SiGe HBTs exhibit less susceptibility to SETs than conventional RF designs, in terms of transient peaks and duration, at the cost of RF performance. Under normal RF operation, the SET-hardened switch is mainly effective in peak reduction, while the LNA and the mixer exhibit reductions in transient peaks as well as transient duration.

Structural characteristics of a gas-liquid flow in a microchannel with a T-shaped mixer

NASA Astrophysics Data System (ADS)

Kuznetsov, V. V.; Kozulin, I. A.

2017-11-01

The results of experimental studies of the structural characteristics of a nitrogen-water mixture flow in a horizontal microchannel provided with a T-shaped mixer are presented. The experiments are performed in a channel with a rectangular cross section of 250 × 315 μm under the conditions of a dominating influence of capillary forces. Structural characteristics of the flow are determined using the two-beam laser scanning and high-speed video capture at a distance of 500 calibers from the inlet in a wide range of reduced gas- and liquid-flow rates. A new method for the identification of flow regimes is proposed based on the statistical treatment of the laser-scanning data, and a map of flow patterns is constructed.

Micromachined Millimeter- and Submillimeter-Wave SIS Heterodyne Receivers for Remote Sensing

NASA Technical Reports Server (NTRS)

Hu, Qing

1998-01-01

A heterodyne mixer with a micromachined horn antenna and a superconductor -insulator-superconductor (SIS) tunnel junction as mixing element is tested in the W-band (75-115 GHz) frequency range. Micromachined integrated horn antennas consist of a dipole antenna suspended on a thin Si3N4 dielectric membrane inside a pyramidal cavity etched in silicon. The mixer performance is optimized by using a backing plane behind the dipole antenna to tune out the capacitance of the tunnel junction. The lowest receiver noise temperature of 30+/-3 K without any correction) is measured at 106 GHz with a 3-dB bandwidth of 8 GHz. This sensitivity is comparable to the state-of-the-art waveguide and quasi-optical SIS receivers, showing the potential use of micromachined horn antennas in imaging arrays.

The Optimization Design of An AC-Electroosmotic Micro mixer

NASA Astrophysics Data System (ADS)

Wang, Yangyang; Suh, Yongkweon; Kang, Sangmo

2007-11-01

We propose the optimization design of an AC-electroosmotic micro-mixer, which is composed of a channel and a series of pairs of electrodes attached on the bottom wall in zigzag patterns. The AC electric field is applied to the electrodes so that a fluid flow takes place around the electrodes across the channel, thus contributing to the mixing of the fluid within the channel. We have performed numerical simulations by using a commercial code (CFX 10) to optimize the shape and pattern of the electrodes via the concept of mixing index. It is found that the best combination of two kinds of electrodes, which leads to good mixing performance, is not simply harmonic one. When the length ratio of the two kinds of electrodes closes to 2:1, we can get the best mixing effect. Furthermore, we will visualize the flow pattern and measure the velocity field with a PTV technique to validate the numerical simulations. In addition, the mixing pattern will be visualized via the experiment.

Surface Modified TiO2 Obscurants for Increased Safety and Performance

DTIC Science & Technology

2012-11-01

based obscurant devices in performance. 15. SUBJECT TERMS Obscurant, visible, IR , smoke, TiO2, aerosol, particle, surface modification...hexamethyldimethoxysilane IR Infrared wavelength LabRAM Lab scale Resonant Acoustic Mixer from Resodyn Corporation LPM Liters Per Minute M106 Currently fielded (Army...trinitrophloroglucinol UV-Vis Ultraviolet-visible wavelengths KEYWORDS Obscurant, visible, IR , smoke, TiO2, aerosol, particle, surface modification

Oxide_Oxide Ceramic Matrix Composite (CMC) Exhaust Mixer Development in the NASA Environmentally Responsible Aviation (ERA) Project

NASA Technical Reports Server (NTRS)

Kiser, J. Douglas; Bansal, Narottam P.; Szelagowski, James; Sokhey, Jagdish; Heffernan, Tab; Clegg, Joseph; Pierluissi, Anthony; Riedell, Jim; Wyen, Travis; Atmur, Steven;

Toward Realization of 2.4 GHz Balunless Narrowband Receiver Front-End for Short Range Wireless Applications.

PubMed

El-Desouki, Munir M; Qasim, Syed Manzoor; BenSaleh, Mohammed S; Deen, M Jamal

2015-05-07

The demand for radio frequency (RF) transceivers operating at 2.4 GHz band has attracted considerable research interest due to the advancement in short range wireless technologies. The performance of RF transceivers depends heavily on the transmitter and receiver front-ends. The receiver front-end is comprised of a low-noise amplifier (LNA) and a downconversion mixer. There are very few designs that focus on connecting the single-ended output LNA to a double-balanced mixer without the use of on-chip transformer, also known as a balun. The objective of designing such a receiver front-end is to achieve high integration and low power consumption. To meet these requirements, we present the design of fully-integrated 2.4 GHz receiver front-end, consisting of a narrow-band LNA and a double balanced mixer without using a balun. Here, the single-ended RF output signal of the LNA is translated into differential signal using an NMOS-PMOS (n-channel metal-oxide-semiconductor, p-channel metal-oxide-semiconductor) transistor differential pair instead of the conventional NMOS-NMOS transistor configuration, for the RF amplification stage of the double-balanced mixer. The proposed receiver circuit fabricated using TSMC 0.18 µm CMOS technology operates at 2.4 GHz and produces an output signal at 300 MHz. The fabricated receiver achieves a gain of 16.3 dB and consumes only 6.74 mW operating at 1.5 V, while utilizing 2.08 mm2 of chip area. Measurement results demonstrate the effectiveness and suitability of the proposed receiver for short-range wireless applications, such as in wireless sensor network (WSN).

Making Wide-IF SIS Mixers with Suspended Metal-Beam Leads

NASA Technical Reports Server (NTRS)

Kaul, Anupama; Bumble, Bruce; Lee, Karen; LeDuc, Henry; Rice, Frank; Zmuidzinas, Jonas

2005-01-01

A process that employs silicon-on-insulator (SOI) substrates and silicon (Si) micromachining has been devised for fabricating wide-intermediate-frequency-band (wide-IF) superconductor/insulator/superconductor (SIS) mixer devices that result in suspended gold beam leads used for radio-frequency grounding. The mixers are formed on 25- m-thick silicon membranes. They are designed to operate in the 200 to 300 GHz frequency band, wherein wide-IF receivers for tropospheric- chemistry and astrophysical investigations are necessary. The fabrication process can be divided into three sections: 1. The front-side process, in which SIS devices with beam leads are formed on a SOI wafer; 2. The backside process, in which the SOI wafer is wax-mounted onto a carrier wafer, then thinned, then partitioned into individual devices; and 3. The release process, in which the individual devices are separated using a lithographic dicing technique. The total thickness of the starting 4-in. (10.16-cm)-diameter SOI wafer includes 25 m for the Si device layer, 0.5 m for the buried oxide (BOX) layer, and 350 m the for Si-handle layer. The front-side process begins with deposition of an etch-stop layer of SiO2 or AlN(x), followed by deposition of a Nb/Al- AlN(x) /Nb trilayer in a load-locked DC magnetron sputtering system. The lithography for four of a total of five layers is performed in a commercial wafer-stepping apparatus. Diagnostic test dies are patterned concurrently at certain locations on the wafer, alongside the mixer devices, using a different mask set. The conventional, self-aligned lift-off process is used to pattern the SIS devices up to the wire level.

180-GHz I-Q Second Harmonic Resistive Mixer MMIC

NASA Technical Reports Server (NTRS)

Kangaslahti, Pekka P.; Lai, Richard; Mei, Xiaobing

2010-01-01

An indium phosphide MMIC (monolithic microwave integrated circuit) mixer was developed, processed, and tested in the NGC 35-nm-gate-length HEMT (high electron mobility transistor) process. This innovation is very compact in size and operates with very low LO power. Because it is a resistive mixer, this innovation does not require DC power. This is an enabling technology for the miniature receiver modules for the GeoSTAR instrument, which is the only viable option for the NRC decadal study mission PATH.

30 GHz monolithic balanced mixers using an ion-implanted FET-compatible 3-inch GaAs wafer process technology

NASA Technical Reports Server (NTRS)

Bauhahn, P.; Contolatis, A.; Sokolov, V.; Chao, C.

1986-01-01

An all ion-implanted Schottky barrier mixer diode which has a cutoff frequency greater than 1000 GHz has been developed. This new device is planar and FET-compatible and employs a projection lithography 3-inch wafer process. A Ka-band monolithic balanced mixer based on this device has been designed, fabricated and tested. A conversion loss of 8 dB has been measured with a LO drive of 10 dBm at 30 GHz.

HYBRID SILICON-ON-SAPPHIRE/SCALED CMOS INTERFERENCE MITIGATION FRONT END BASED ON SIMULTANEOUS NOISE CANCELLATION, ACTIVE-INTERFERENCE CANCELLATION AND N-PATH-MIXER FILTERING

DTIC Science & Technology

2017-04-01

INTERFERENCE-CANCELLATION AND N-PATH-MIXER FILTERING Harish Krishnaswamy, Negar Reiskarimian, and Linxiao Zhang Columbia University APRIL 2017 Final...INTERFERENCE-CANCELLATION AND N- PATH-MIXER FILTERING 5a. CONTRACT NUMBER FA8650-14-1-7414 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61101E/62716E 6...techniques for developing interference mitigation technology (IMT) enabling frequency-agile, reconfigurable filter -less receivers. Wideband noise

Ethylene thiourea: thyroid function in two groups of exposed workers.

PubMed Central

Smith, D M

1984-01-01

Ethylene thiourea is manufactured at one factory in the United Kingdom and is mixed into masterbatch rubber at another. Clinical examinations and thyroid function tests were carried out over a period of three years on eight process workers and five mixers and on matched controls. The results show that the exposed mixers, but not exposed process workers, have significantly lower levels of total thyroxine (T4) than the controls. One mixer had an appreciably raised level of thyroid stimulation hormone (TSH). PMID:6743584

Ethylene thiourea: thyroid function in two groups of exposed workers.

PubMed

Smith, D M

1984-08-01

Ethylene thiourea is manufactured at one factory in the United Kingdom and is mixed into masterbatch rubber at another. Clinical examinations and thyroid function tests were carried out over a period of three years on eight process workers and five mixers and on matched controls. The results show that the exposed mixers, but not exposed process workers, have significantly lower levels of total thyroxine (T4) than the controls. One mixer had an appreciably raised level of thyroid stimulation hormone (TSH).

Production of high-quality polydisperse construction mixes for additive 3D technologies.

NASA Astrophysics Data System (ADS)

Gerasimov, M. D.; Brazhnik, Yu V.; Gorshkov, P. S.; Latyshev, S. S.

2018-03-01

The paper describes a new design of a mixer allowing production of high quality polydisperse powders, used in additive 3D technologies. A new principle of dry powder particle mixing is considered, implementing a possibility of a close-to-ideal distribution of such particles in common space. A mathematical model of the mixer is presented, allowing evaluating quality indicators of the produced mixture. Experimental results are shown and rational values of process parameters of the mixer are obtained.

Variable volume combustor with aerodynamic support struts

DOEpatents

Ostebee, Heath Michael; Johnson, Thomas Edward; Stewart, Jason Thurman; Keener, Christopher Paul

2017-03-07

The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and providing the flow of fuel therethrough. The support struts may include an aerodynamic contoured shape so as to distribute evenly a flow of air to the micro-mixer fuel nozzles.

High-quality poly-dispersed mixtures applied in additive 3D technologies.

NASA Astrophysics Data System (ADS)

Gerasimov, M. D.; Brazhnik, Yu V.; Gorshkov, P. S.; Latyshev, S. S.

2018-03-01

The paper describes the new mixer design to obtain high-quality poly-dispersed powders applied in additive 3D technologies. It also considers a new mixing principle of dry powder particles ensuring the distribution of such particles in the total volume, which is close to ideal. The paper presents the mathematical model of mixer operation providing for the quality assessment of the ready mixtures. Besides, it demonstrates experimental results and obtained rational values of mixer process parameters.

Mixing and NOx Emission Calculations of Confined Reacting Jet Flows in Cylindrical and Annular Ducts

NASA Technical Reports Server (NTRS)

Oechsle, Victor L.; Connor, Christopher H.; Holdeman, James D. (Technical Monitor)

2000-01-01

Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A three-dimensional computational fluid dynamics (CFD) code has been used to predict the mixing flow field characteristics and NOx emission in a quench section of a rich-burn/quick-mix/lean-burn (RQL) combustor. Sixty configurations have been analyzed in both circular and annular geometries in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying the number of orifices per row and orifice shape. Other parameters such as J (momentum-flux ratio), MR (mass flowrate ratio), DR (density ratio), and mixer sector orifice ACd (effective orifice area) were maintained constant throughout the entire study. The results indicate that the mixing flow field can be correlated with the NOx production if they are referenced with the stoichiometric equivalence ratio value and not the equilibrium value. The mixing flowfields in both circular and annular mixers are different. The penetration of equal jets in both annular and circular geometries is vastly different which significantly affects the performance of the mixing section. In the computational results with the circular mixer, most of the NOx formation occurred behind the orifice starting at the orifice wake region. General trends have been observed in the NOx production as the number of orifices is changed and this appears to be common for all hole configurations and mixer types (circular or annular). The performance of any orifice shape (in producing minimum NOx) appears to be acceptable if the number of orifices can be freely varied in order to attain the optimum jet penetration.

Computational Fluid Dynamics (CFD) Simulations of Jet Mixing in Tanks of Different Scales

NASA Technical Reports Server (NTRS)

Breisacher, Kevin; Moder, Jeffrey

2010-01-01

For long-duration in-space storage of cryogenic propellants, an axial jet mixer is one concept for controlling tank pressure and reducing thermal stratification. Extensive ground-test data from the 1960s to the present exist for tank diameters of 10 ft or less. The design of axial jet mixers for tanks on the order of 30 ft diameter, such as those planned for the Ares V Earth Departure Stage (EDS) LH2 tank, will require scaling of available experimental data from much smaller tanks, as well designing for microgravity effects. This study will assess the ability for Computational Fluid Dynamics (CFD) to handle a change of scale of this magnitude by performing simulations of existing ground-based axial jet mixing experiments at two tank sizes differing by a factor of ten. Simulations of several axial jet configurations for an Ares V scale EDS LH2 tank during low Earth orbit (LEO) coast are evaluated and selected results are also presented. Data from jet mixing experiments performed in the 1960s by General Dynamics with water at two tank sizes (1 and 10 ft diameter) are used to evaluate CFD accuracy. Jet nozzle diameters ranged from 0.032 to 0.25 in. for the 1 ft diameter tank experiments and from 0.625 to 0.875 in. for the 10 ft diameter tank experiments. Thermally stratified layers were created in both tanks prior to turning on the jet mixer. Jet mixer efficiency was determined by monitoring the temperatures on thermocouple rakes in the tanks to time when the stratified layer was mixed out. Dye was frequently injected into the stratified tank and its penetration recorded. There were no velocities or turbulence quantities available in the experimental data. A commercially available, time accurate, multi-dimensional CFD code with free surface tracking (FLOW-3D from Flow Science, Inc.) is used for the simulations presented. Comparisons are made between computed temperatures at various axial locations in the tank at different times and those observed experimentally. The affect of various modeling parameters on the agreement obtained are assessed.

Apparatus for silicon nitride precursor solids recovery

DOEpatents

Crosbie, Gary M.; Predmesky, Ronald L.; Nicholson, John M.

1995-04-04

Method and apparatus are provided for collecting reaction product solids entrained in a gaseous outflow from a reaction situs, wherein the gaseous outflow includes a condensable vapor. A condensate is formed of the condensable vapor on static mixer surfaces within a static mixer heat exchanger. The entrained reaction product solids are captured in the condensate which can be collected for further processing, such as return to the reaction situs. In production of silicon imide, optionally integrated into a production process for making silicon nitride caramic, wherein reactant feed gas comprising silicon halide and substantially inert carrier gas is reacted with liquid ammonia in a reaction vessel, silicon imide reaction product solids entrained in a gaseous outflow comprising residual carrier gas and vaporized ammonia can be captured by forming a condensate of the ammonia vapor on static mixer surfaces of a static mixer heat exchanger.

Method for silicon nitride precursor solids recovery

DOEpatents

Crosbie, Gary M.; Predmesky, Ronald L.; Nicholson, John M.

1992-12-15

Method and apparatus are provided for collecting reaction product solids entrained in a gaseous outflow from a reaction situs, wherein the gaseous outflow includes a condensable vapor. A condensate is formed of the condensable vapor on static mixer surfaces within a static mixer heat exchanger. The entrained reaction product solids are captured in the condensate which can be collected for further processing, such as return to the reaction situs. In production of silicon imide, optionally integrated into a production process for making silicon nitride caramic, wherein reactant feed gas comprising silicon halide and substantially inert carrier gas is reacted with liquid ammonia in a reaction vessel, silicon imide reaction product solids entrained in a gaseous outflow comprising residual carrier gas and vaporized ammonia can be captured by forming a condensate of the ammonia vapor on static mixer surfaces of a static mixer heat exchanger.

Terahertz Radiation Heterodyne Detector Using Two-Dimensional Electron Gas in a GaN Heterostructure

NASA Technical Reports Server (NTRS)

Karasik, Boris S.; Gill, John J.; Mehdi, Imran; Crawford, Timothy J.; Sergeev, Andrei V.; Mitin, Vladimir V.

2012-01-01

High-resolution submillimeter/terahertz spectroscopy is important for studying atmospheric and interstellar molecular gaseous species. It typically uses heterodyne receivers where an unknown (weak) signal is mixed with a strong signal from the local oscillator (LO) operating at a slightly different frequency. The non-linear mixer devices for this frequency range are unique and are not off-the-shelf commercial products. Three types of THz mixers are commonly used: Schottky diode, superconducting hot-electron bolometer (HEB), and superconductor-insulation-superconductor (SIS) junction. A HEB mixer based on the two-dimensional electron gas (2DEG) formed at the interface of two slightly dissimilar semiconductors was developed. This mixer can operate at temperatures between 100 and 300 K, and thus can be used with just passive radiative cooling available even on small spacecraft.

Fiber optic multiplex optical transmission system

NASA Technical Reports Server (NTRS)

Bell, C. H. (Inventor)

1977-01-01

A multiplex optical transmission system which minimizes external interference while simultaneously receiving and transmitting video, digital data, and audio signals is described. Signals are received into subgroup mixers for blocking into respective frequency ranges. The outputs of these mixers are in turn fed to a master mixer which produces a composite electrical signal. An optical transmitter connected to the master mixer converts the composite signal into an optical signal and transmits it over a fiber optic cable to an optical receiver which receives the signal and converts it back to a composite electrical signal. A de-multiplexer is coupled to the output of the receiver for separating the composite signal back into composite video, digital data, and audio signals. A programmable optic patch board is interposed in the fiber optic cables for selectively connecting the optical signals to various receivers and transmitters.

Superconductive hot-electron-bolometer mixer receiver for 800-GHz operation

NASA Astrophysics Data System (ADS)

Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Papa, D. C.; Hunter, T. R.; Paine, S. N.; Patt, F.; Gol'Tsman, G.; Cherednichenko, S.; Voronov, B.; Gershenzon, E.

2000-04-01

In this paper, we describe a superconductive hot-electron-bolometer mixer receiver designed to operate in the partially transmissive 350-μm atmospheric window. The receiver employs an NbN thin-film microbridge as the mixer element, in which the main cooling mechanism of the hot electrons is through electron-phonon interaction. At a local-oscillator frequency of 808 GHz, the measured double-sideband receiver noise temperature is Trx=970 K, across a 1-GHz intermediate-frequency bandwidth centered at 1.8 GHz. We have measured the linearity of the receiver and the amount of local-oscillator power incident on the mixer for optimal operation, which is PLO ≈ 1 microwatt. This receiver was used in making observations as a facility instrument at the Heinrich Hertz Telescope, Mt. Graham, AZ, during the 1998-1999 winter observing season.

A Comparison of Combustion Dynamics for Multiple 7-Point Lean Direct Injection Combustor Configurations

NASA Technical Reports Server (NTRS)

Tacina, Kathleen M.; Hicks, Yolanda R.

2017-01-01

The combustion dynamics of two 7-point lean direct injection (LDI) combustor configurations are compared. This 7-point LDI configuration has a circular cross section, with a center ("pilot") fuel-air mixer surrounded by six outer ("main") fuel-air mixers. Each fuel-air mixer consists of an axial air swirler followed by a converging-diverging venturi. A simplex fuel injector is inserted through the center of the air swirler, with the fuel injector tip located near the venturi throat. All 7 fuel-air mixers are identical except for the swirler blade angle. In the 'all-60' configuration, the swirler blade angle was 60 deg for all fuel-air mixers. In the '45-60' configuration, the swirler blade angle was 60 deg on the center and 45 deg on the outer fuel-air mixers. Testing was done in a 5-atm flame tube with inlet air temperatures from 630 to 830 F and equivalence ratios from 0.2 to 0.7. Combustion dynamics were measured using a cooled PCB pressure transducer flush-mounted in the wall of the combustor test section. Both configurations had large pressure fluctuations (greater than 2 psi peak-peak) near 730 Hz, the quarter-wave frequency. The all-60 configuration also had large pressure fluctuations near 1170 Hz; the 45-60 configuration did not. The 45-60 configuration had large pressure fluctuations near 480 Hz; the all-60 configuration did not.

Noise and Bandwidth Measurements of Diffusion-Cooled Nb Hot-Electron Bolometer Mixers at Frequencies Above the Superconductive Energy Gap

NASA Technical Reports Server (NTRS)

Wyss, R. A.; Karasik, B. S.; McGrath, W. R.; Bumble, B.; LeDuc, H.

1999-01-01

Diffusion-cooled Nb hot-electron bolometer (HEB) mixers have the potential to simultaneously achieve high intermediate frequency (IF) bandwidths and low mixer noise temperatures for operation at THz frequencies (above the superconductive gap energy). We have measured the IF signal bandwidth at 630 GHz of Nb devices with lengths L = 0.3, 0.2, and 0.1 micrometer in a quasioptical mixer configuration employing twin-slot antennas. The 3-dB EF bandwidth increased from 1.2 GHz for the 0.3 gm long device to 9.2 GHz for the 0.1 gm long device. These results demonstrate the expected 1/L squared dependence of the IF bandwidth at submillimeter wave frequencies for the first time, as well as the largest EF bandwidth obtained to date. For the 0.1 gm device, which had the largest bandwidth, the double sideband (DSB) noise temperature of the receiver was 320-470 K at 630 GHz with an absorbed LO power of 35 nW, estimated using the isothermal method. A version of this mixer with the antenna length scaled for operation at 2.5 THz has also been tested. A DSB receiver noise temperature of 1800 plus or minus 100 K was achieved, which is about 1,000 K lower than our previously reported results. These results demonstrate that large EF bandwidth and low-noise operation of a diffusion-cooled HEB mixer is possible at THz frequencies with the same device geometry.

Linear Quadratic Tracking Design for a Generic Transport Aircraft with Structural Load Constraints

NASA Technical Reports Server (NTRS)

Burken, John J.; Frost, Susan A.; Taylor, Brian R.

2011-01-01

When designing control laws for systems with constraints added to the tracking performance, control allocation methods can be utilized. Control allocations methods are used when there are more command inputs than controlled variables. Constraints that require allocators are such task as; surface saturation limits, structural load limits, drag reduction constraints or actuator failures. Most transport aircraft have many actuated surfaces compared to the three controlled variables (such as angle of attack, roll rate & angle of side slip). To distribute the control effort among the redundant set of actuators a fixed mixer approach can be utilized or online control allocation techniques. The benefit of an online allocator is that constraints can be considered in the design whereas the fixed mixer cannot. However, an online control allocator mixer has a disadvantage of not guaranteeing a surface schedule, which can then produce ill defined loads on the aircraft. The load uncertainty and complexity has prevented some controller designs from using advanced allocation techniques. This paper considers actuator redundancy management for a class of over actuated systems with real-time structural load limits using linear quadratic tracking applied to the generic transport model. A roll maneuver example of an artificial load limit constraint is shown and compared to the same no load limitation maneuver.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickenheim, B.; Hansen, E.; Leishear, R.

A 10-inch READCO mixer is used for mixing the premix (45 (wt%) fly ash, 45 wt% slag, and 10 wt% portland cement) with salt solution in the Saltstone Production Facility (SPF). The Saltstone grout free falls into the grout hopper which feeds the suction line leading to the Watson SPX 100 duplex hose pump. The Watson SPX 100 pumps the grout through approximately 1500 feet of piping prior to being discharged into the Saltstone Disposal Facility (SDF) vaults. The existing grout hopper has been identified by the Saltstone Enhanced Low Activity Waste Disposal (ELAWD) project for re-design. The current nominalmore » working volume of this hopper is 12 gallons and does not permit handling an inadvertent addition of excess dry feeds. Saltstone Engineering has proposed a new hopper tank that will have a nominal working volume of 300 gallons and is agitated with a mechanical agitator. The larger volume hopper is designed to handle variability in the output of the READCO mixer and process upsets without entering set back during processing. The objectives of this task involve scaling the proposed hopper design and testing the scaled hopper for the following processing issues: (1) The effect of agitation on radar measurement. Formation of a vortex may affect the ability to accurately measure the tank level. The agitator was run at varying speeds and with varying grout viscosities to determine what parameters cause vortex formation and whether measurement accuracy is affected. (2) A dry feeds over addition. Engineering Calculating X-ESR-Z-00017 1 showed that an additional 300 pounds of dry premix added to a 300 gallon working volume would lower the water to premix ratio (W/P) from the nominal 0.60 to 0.53 based on a Salt Waste Processing Facility (SWPF) salt simulant. A grout with a W/P of 0.53 represents the upper bound of grout rheology that could be processed at the facility. A scaled amount of dry feeds will be added into the hopper to verify that this is a recoverable situation. (3) The necessity of baffles in the hopper. The preference of the facility is not to have baffles in the hopper; however, if the initial testing indicates inadequate agitation or difficulties with the radar measurement, baffles will be tested.« less

GUI for Computational Simulation of a Propellant Mixer

NASA Technical Reports Server (NTRS)

Figueroa, Fernando; Richter, Hanz; Barbieri, Enrique; Granger, Jamie

2005-01-01

Control Panel is a computer program that generates a graphical user interface (GUI) for computational simulation of a rocket-test-stand propellant mixer in which gaseous hydrogen (GH2) is injected into flowing liquid hydrogen (LH2) to obtain a combined flow having desired thermodynamic properties. The GUI is used in conjunction with software that models the mixer as a system having three inputs (the positions of the GH2 and LH2 inlet valves and an outlet valve) and three outputs (the pressure inside the mixer and the outlet flow temperature and flow rate). The user can specify valve characteristics and thermodynamic properties of the input fluids via userfriendly dialog boxes. The user can enter temporally varying input values or temporally varying desired output values. The GUI provides (1) a set-point calculator function for determining fixed valve positions that yield desired output values and (2) simulation functions that predict the response of the mixer to variations in the properties of the LH2 and GH2 and manual- or feedback-control variations in valve positions. The GUI enables scheduling of a sequence of operations that includes switching from manual to feedback control when a certain event occurs.

Numerical Analysis of Micromixers for Optimization of Mixing Action

NASA Astrophysics Data System (ADS)

Panta, Yogendra; Adhikari, Param

2011-03-01

Micro-bio/chemical applications often require rapid and uniform mixing of a number of fluid streams that carries bio/chemical species in the solution. At microscale, fluid flow is highly laminar with low Reynolds number, fluids mixing mechanism is primarily by diffusion and free from any turbulence. Demand for highly efficient micromixers for microfluidic networks is due to slower mixing process for larger bio-molecules such as peptides, proteins, and nucleic acids compared to micro-scale molecules. Passive and active mixers are two basic mixers that are currently in use for these applications. Passive mixers often require very long mixing channels where are most active mixers require bulky moving parts to stir the fluids. In this study, electroosmotic effects orthogonally aligned with the fluid flowstream are utilized for optimum mixing effect in various micromixers. Cross-dependencies among several geometrical, electrical, and fluid parameters and their significance are studied in order to achieve an optimum mixing effect. It has been planned to optimize the mixer by non-moving stirring actions provided by an external magnetic field. Acknowledgements to School of Graduate Studies and Research at YSU for URC Grant and RP Award 2009-2010.

Superconducting Nb DHEB Mixer Arrays for Far-Infrared Spectroscopy

NASA Technical Reports Server (NTRS)

Gerecht, E.; Reintsema, C. D.; Grossman, E. N.; Betz, A. L.; Boreiko, R. T.

2001-01-01

We are developing a heterodyne focal plane array with up to eight elements to study lines of the interstellar medium and planetary atmospheres with frequencies of 2 THz and above. Our fabrication process utilizes selective ion milling techniques to produce Nb Diffusion-Cooled Hot Electron Bolometric (DHEB) mixers from a bilayer thin film of Au/Nb deposited on a silicon substrate. A micro-bridge of 10 nm thick Nb forms the HEB device. The first generation of devices with lateral dimensions of 100 nm by 80 nm were fabricated at the feed of a broadband spiral antenna with a frequency response designed for up to 16 THz. Harmonic multiplier sources becoming available within the next few years should have sufficient power to provide a local-oscillator source for small-format, quasi-optically coupled arrays of these mixers. First generation devices measured at our laboratory have demonstrated a critical temperature (Tc) of 4.8 K with a 0.5 K transition width. These DHEB mixers are expected to have an optimum operational temperature of 1.8-2.0 K. The current four element array mixer block will ultimately be replaced by a dual polarization slot-ring array configuration with up to eight elements.

Performance analysis of vortex based mixers for confined flows

NASA Astrophysics Data System (ADS)

Buschhagen, Timo

The hybrid rocket is still sparsely employed within major space or defense projects due to their relatively poor combustion efficiency and low fuel grain regression rate. Although hybrid rockets can claim advantages in safety, environmental and performance aspects against established solid and liquid propellant systems, the boundary layer combustion process and the diffusion based mixing within a hybrid rocket grain port leaves the core flow unmixed and limits the system performance. One principle used to enhance the mixing of gaseous flows is to induce streamwise vorticity. The counter-rotating vortex pair (CVP) mixer utilizes this principle and introduces two vortices into a confined flow, generating a stirring motion in order to transport near wall media towards the core and vice versa. Recent studies investigated the velocity field introduced by this type of swirler. The current work is evaluating the mixing performance of the CVP concept, by using an experimental setup to simulate an axial primary pipe flow with a radially entering secondary flow. Hereby the primary flow is altered by the CVP swirler unit. The resulting setup therefore emulates a hybrid rocket motor with a cylindrical single port grain. In order to evaluate the mixing performance the secondary flow concentration at the pipe assembly exit is measured, utilizing a pressure-sensitive paint based procedure.

FRONT (SOUTH) ELEVATION, MIXER RUINS (CENTER) WITH STACKS (LEFT) AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FRONT (SOUTH) ELEVATION, MIXER RUINS (CENTER) WITH STACKS (LEFT) AND POWER HOUSE (RIGHT). - Tennessee Coal & Iron Company, Ensley Works, Open Hearth Furnace (Ruins), West of Ensley commercial & residential districts, Birmingham, Jefferson County, AL

FRONT (SOUTH) ELEVATION, MIXER RUINS (CENTER) WITH STACKS (LEFT) AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FRONT (SOUTH) ELEVATION, MIXER RUINS (CENTER) WITH STACKS (LEFT) AND POWER HOUSE (RIGHT - Tennessee Coal & Iron Company, Ensley Works, Open Hearth Furnace (Ruins), West of Ensley commercial & residential districts, Birmingham, Jefferson County, AL

Credit WCT. Original 2Y4" x 2Y4" color negative is housed ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit WCT. Original 2-Y4" x 2-Y4" color negative is housed in the JPL Photography Laboratory, Pasadena, California. JPL staff members Harold Anderson and John Morrow cast grain from the 1-gallon BakerPerkins model 4-PU mixer. A 1-pint Baker-Perkins model 2-PX mixer stands to the left in this view (JPL negative no. JPL-10295BC, 27 January 1989) - Jet Propulsion Laboratory Edwards Facility, Mixer & Casting Building, Edwards Air Force Base, Boron, Kern County, CA

Noise Temperature and IF Bandwidth of a 530 GHz Heterodyne Receiver Employing a Diffusion-Cooled Superconducting Hot-Electron Mixer

NASA Technical Reports Server (NTRS)

Skalare, A.; McGrath, W. R.; Bumble, B.; LeDuc, H. G.; Burke, P. J.; Verheijen, A. A.; Prober, D. E.

1995-01-01

We report on the first heterodyne measurements with a diffusion-cooled hot-electron bolometer mixer in the submillimeter wave band, using a waveguide mixer cooled to 2.2 K. The best receiver noise temperature at a local oscillator frequency of 533 GHz and an intermediate frequency of 1.4 GHz was 650 K (double sideband). The 3 dB IF roll-off frequency was around 1.7 to 1.9 GHz, with a weak dependence on the device bias conditions.

Variable volume combustor with aerodynamic fuel flanges for nozzle mounting

DOE Office of Scientific and Technical Information (OSTI.GOV)

McConnaughhay, Johnie Franklin; Keener, Christopher Paul; Johnson, Thomas Edward

2016-09-20

The present application provides a combustor for use with a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles and a fuel injection system for providing a flow of fuel to the micro-mixer fuel nozzles. The fuel injection system may include a number of support struts supporting the fuel nozzles and for providing the flow of fuel therethrough. The fuel injection system also may include a number of aerodynamic fuel flanges connecting the micro-mixer fuel nozzles and the support struts.

Experimental studies at the Idaho Chemical Processing Plant on actinide partitioning from acidic nuclear wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

McIssaac, L. D.; Baker, J. D.; Meikrantz, D. H.

1980-01-01

Wastes generated at ICPP and in the reprocessing of LWR fuel is discussed separately. DHDECMP is used as extractant. Studies on DHDECMP purification and toxicity, diluent effects, reaction kinetics, radioloysis, mixer-settler performance, etc. are reported. 10 tables, 3 figures. (DLC)

HgCdTe Photoconductive Mixers for 2-8 THz

NASA Technical Reports Server (NTRS)

Betz, A. L.; Boreiko, R. T.; Sivananthan, S.; Ashokan, R.

2001-01-01

Heterodyne spectroscopy has been taken to wavelengths as short as 63 micrometers with Schottky-diode mixers. Schottkys, however, are relatively insensitive compared to superconducting mixers such as the hot-electron microbolometer (HEB), which has an effective quantum efficiency of 3% at 120 micrometers (2.5 THz). Although HEB sensitivities are bound to improve, there will always be losses associated with antenna coupling of radiation into sub-micron size devices. Another approach to far infrared (FIR) mixer design is to use a photoconductive device which can be made much larger than a wavelength, and thus act as its own antenna. For example, HgCdTe photodiodes have been used as mixers in the lambda = 10 micrometers band for over 25 years, with sensitivities now only a factor of 2 from the quantum-noise-limit. HgCdTe can also be applied at FIR wavelengths, but surprisingly little work has been done to date. The exception is the pioneering work of Spears and Kostiuk and Spears, who developed HgCdTe photomixers for the 20-120 micrometer region. The spectral versatility of the HgCdTe alloy is well recognized for wavelengths as long as 8-20 micrometers. What is not so recognized, however, is that theoretically there is no long wavelength limit for appropriately composited HgCdTe. Although Spears successfully demonstrated a photoconductive response from HgCdTe at 120 micrometers, this initial effort was apparently never followed up, in part because of the difficulty of controlling the HgCdTe alloy composition with liquid-phase-epitaxy (LPE) techniques. With the availability of precise molecular-beam-epitaxy (MBE) since the early 1990's, it is now appropriate to reconsider HgCdTe for detector applications longward of lambda = 20 micrometers. We recently initiated an effort to fabricate detectors and mixers using II-VI materials for FIR wavelengths. Of particular interest are device structures called superlattices, which offer a number of advantages for high sensitivity direct detectors and very long wavelength heterodyne mixers.

2.32 THz quantum cascade laser frequency-locked to the harmonic of a microwave synthesizer source.

PubMed

Danylov, Andriy A; Light, Alexander R; Waldman, Jerry; Erickson, Neal R; Qian, Xifeng; Goodhue, William D

2012-12-03

Frequency stabilization of a THz quantum cascade laser (QCL) to the harmonic of a microwave source has been accomplished using a Schottky diode waveguide mixer designed for harmonic mixing. The 2.32 THz, 1.0 milliwatt CW QCL is coupled into the signal port of the mixer and a 110 GHz signal, derived from a harmonic of a microwave synthesizer, is coupled into the IF port. The difference frequency between the 21st harmonic of 110 GHz and the QCL is used in a discriminator to adjust the QCL bias current to stabilize the frequency. The short-term frequency jitter is reduced from 550 kHz to 4.5 kHz (FWHM) and the long-term frequency drift is eliminated. This performance is compared to that of several other THz QCL frequency stabilization techniques.

High-power terahertz lasers with excellent beam quality for local oscillator sources

NASA Astrophysics Data System (ADS)

Williams, Benjamin

Many molecular species that compose the interstellar medium have strong spectral features in the 2-5 THz range, and heterodyne spectroscopy is required to obtain ~km/s velocity resolution to resolve their complicated lineshapes and disentangle them from the background. Understanding the kinetics and energetics within the gas clouds of the interstellar medium is critical to understanding star formation processes and validating theories of galactic evolution. Herschel Observatory's heterodyne HIFI instrument provided several years of high-spectral-resolution measurements of the interstellar medium, although only up to 1.9 THz. The next frontier for heterodyne spectroscopy is the 2-6 THz region. However, development of heterodyne receivers above 2 THz has been severely hindered by a lack of convenient coherent sources of sufficient power to serve as local oscillators (LOs). The recently developed quantum-cascade (QC) lasers are emerging as candidates for LOs in the 1.5-5 THz range. The current generation of single-mode THz QC-lasers can provide a few milliwatts of power in a directive beam, and will be sufficient to pump single pixels and small-format heterodyne arrays (~10 elements). This proposal looks beyond the state-of-the-art, to the development of large format heterodyne arrays which contain on the order of 100-1000 elements. LO powers on the order of 10-100 mW delivered in a high-quality Gaussian beam will be needed to pump the mixer array - not only because of the microwatt mixer power requirement, but to account for large anticipated losses in LO coupling and distribution. Large format heterodyne array instruments are attractive for a dramatic speedup of mapping of the interstellar medium, particularly on airborne platforms such as the Stratospheric Observatory for Infrared Astronomy (SOFIA), and on long duration balloon platforms such as the Stratospheric Terahertz Observatory (STO), where observation time is limited. The research goal of this proposal is to demonstrate a new concept for terahertz quantum-cascade (QC) lasers designed to deliver scalable continuous-wave output power in the range of 10 to 100 mW or more in a near-diffraction limited output beam: a chip-scale THz quantum-cascade vertical-external-cavity-surface-emitting-laser (QC-VECSEL). We focus here on the development of a chip-scale version of size < 1 cm3 that oscillates in a single mode and can readily fit on a cold stage. The enabling technology for this proposed laser is an active metasurface reflector, which is comprised of a sparse array of antenna-coupled THz QC-laser sub-cavities. The metasurface reflector is part of the laser cavity such that multiple THz QC-laser sub-cavities are locked to a high-quality-factor cavity mode, which allows for scalable power combining with a favorable geometry for thermal dissipation and continuous-wave operation. We propose an integrated design, modeling, and experimental approach to design, fabricate, and characterize amplifying reflective QC metasurfaces and QC-VECSEL lasers. Demonstration laser devices will be developed at 2.7 THz and 4.7 THz, near the important frequencies for HD at 2.675 THz (for measurements of the hydrogen deuterium ratio and probing past star formation), and OI at 4.745 THz (a major coolant for photo-dissociation regions in giant molecular clouds). High resolution frequency measurements will be performed on a demonstration device at 2.7 THz will using downconversion with a Schottky diode sub-harmonic mixer to characterize the spectral purity, linewidth, and fine frequency tuning of this new type of QC-laser. This proposed laser is supporting technology for next-generation terahertz detectors.

FDC Mentor-Mentee Mixer Breaks the Ice Between Investigators and Trainees | Poster

Cancer.gov

The Frederick Diversity Committee’s mentor-mentee mixer gave research trainees, senior investigators, scientists, and administrative staff a chance to meet and mingle over refreshments and games following the Spring Research Festival.

High-frequency fluctuation measurements by far-infrared laser Faraday-effect polarimetry-interferometry and forward scattering system on MST.

PubMed

Ding, W X; Lin, L; Duff, J R; Brower, D L

2014-11-01

Magnetic fluctuation-induced transport driven by global tearing modes has been measured by Faraday-effect polarimetry and interferometry (phase measurements) in the MST reversed field pinch. However, the role of small-scale broadband magnetic and density turbulence in transport remains unknown. In order to investigate broadband magnetic turbulence, we plan to upgrade the existing detector system by using planar-diode fundamental waveguide mixers optimized for high sensitivity. Initial tests indicate these mixers have ×10 sensitivity improvement compared to currently employed corner-cube Schottky-diode mixers and ×5 lower noise. Compact mixer design will allow us to resolve the wavenumbers up to k ∼ 1-2 cm(-1) for beam width w = 1.5 cm and 15 cm(-1) for beam width w = 2 mm. The system can also be used to measure the scattered signal (amplitude measurement) induced by both plasma density and magnetic fluctuations.

Photoresponsive Passive Micromixers Based on Spiropyran Size-Tunable Hydrogels.

PubMed

Ter Schiphorst, Jeroen; Melpignano, Giuseppe G; Amirabadi, Hossein Eslami; Houben, Menno H J M; Bakker, Sterre; den Toonder, Jaap M J; Schenning, Albertus P H J

2018-01-01

Microfluidic devices allow the manipulation of fluids down to the micrometer scale and are receiving a lot of attention for applications where low volumes and high throughputs are required. In these micro channels, laminar flow usually dominates, which requires long residence times of the fluids, limiting the flow speed and throughput. Here a switchable passive mixer has been developed to control mixing and to easily clean microchannels. The mixer is based on a photoresponsive spiropyran based hydrogel of which the dimensions can be tuned by changing the intensity of the light. The size-tunable gels have been used to fabricate a passive slanted groove mixer that can be switched off by light allowing to change mixing of microfluidics to non-mixed flows. These findings open new possibilities for multi-purpose microfluidic devices where mixers and valves can be tuned by light. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Drug residues recovered in feed after various feedlot mixer truck cleanout procedures.

PubMed

Van Donkersgoed, Joyce; Sit, Dan; Gibbons, Nicole; Ramogida, Caterina; Hendrick, Steve

2010-01-01

A study was conducted to determine the effectiveness of two methods of equipment cleanout, sequencing or flushing, for reducing drug carryover in feedlot mixer trucks. Feed samples were collected from total mixed rations before and after various feed mixer equipment cleanout procedures. Medicated rations contained either 11 ppm of tylosin or 166 or 331 ppm of chlortetracycline. There were no differences between sequencing and flushing or between flushing with dry barley and flushing with barley silage in the median proportion of drug recovered in the next ration. A larger drug reduction was achieved using flush material at a volume of 10 versus 5% of the mixer capacity and mixing the flush material for 3 versus 4 min. Regardless of the drug or prescription concentrations in the total mixed rations or the equipment cleanout procedure used, concentrations of chlortetracycline and tylosin recovered were very low.

Instrumentation for measurement of aircraft noise and sonic boom

NASA Technical Reports Server (NTRS)

Zuckerwar, A. J. (Inventor)

1975-01-01

A jet aircraft noise and sonic boom measuring device which converts sound pressure into electric current is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable, amplified by a zero drive amplifier and recorded on magnetic tape. The converter is comprised of a local oscillator, a dual-gate field-effect transistor (FET) mixer and a voltage regulator/impedance translator. A carrier voltage that is applied to one of the gates of the FET mixer is generated by the local oscillator. The microphone signal is mixed with the carrier to produce an electrical current at the frequency of vibration of the microphone diaphragm by the FET mixer. The voltage of the local oscillator and mixer stages is regulated, the carrier at the output is eliminated, and a low output impedance at the cable terminals is provided by the voltage regulator/impedance translator.

40 CFR 63.176 - Quality improvement program for pumps.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., operating or maintenance practices, and pump or pump seal designs or technologies that have poorer than... shall also be used to determine if there are superior performing pump or pump seal technologies that are... average emission performance. A superior performing pump or pump seal technology is one with a leak...

40 CFR 63.176 - Quality improvement program for pumps.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., operating or maintenance practices, and pump or pump seal designs or technologies that have poorer than... shall also be used to determine if there are superior performing pump or pump seal technologies that are... average emission performance. A superior performing pump or pump seal technology is one with a leak...

40 CFR 63.1035 - Quality improvement program for pumps.

Code of Federal Regulations, 2013 CFR

2013-07-01

... determine the services, operating or maintenance practices, and pump or pump seal designs or technologies... analysis shall also be used to determine if there are superior performing pump or pump seal technologies... with poorer than average emission performance. A superior performing pump or pump seal technology is...

40 CFR 63.1035 - Quality improvement program for pumps.

Code of Federal Regulations, 2012 CFR

2012-07-01

... determine the services, operating or maintenance practices, and pump or pump seal designs or technologies... analysis shall also be used to determine if there are superior performing pump or pump seal technologies... with poorer than average emission performance. A superior performing pump or pump seal technology is...

40 CFR 63.1035 - Quality improvement program for pumps.

Code of Federal Regulations, 2011 CFR

2011-07-01

... determine the services, operating or maintenance practices, and pump or pump seal designs or technologies... analysis shall also be used to determine if there are superior performing pump or pump seal technologies... with poorer than average emission performance. A superior performing pump or pump seal technology is...

40 CFR 63.1035 - Quality improvement program for pumps.

Code of Federal Regulations, 2014 CFR

2014-07-01

... determine the services, operating or maintenance practices, and pump or pump seal designs or technologies... analysis shall also be used to determine if there are superior performing pump or pump seal technologies... with poorer than average emission performance. A superior performing pump or pump seal technology is...

40 CFR 63.176 - Quality improvement program for pumps.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., operating or maintenance practices, and pump or pump seal designs or technologies that have poorer than... shall also be used to determine if there are superior performing pump or pump seal technologies that are... average emission performance. A superior performing pump or pump seal technology is one with a leak...

LOX/LH2 vane pump for auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Hemminger, J. A.; Ulbricht, T. E.

1985-01-01

Positive displacement pumps offer potential efficiency advantages over centrifugal pumps for future low thrust space missions. Low flow rate applications, such as space station auxiliary propulsion or dedicated low thrust orbiter transfer vehicles, are typical of missions where low flow and high head rise challenge centrifugal pumps. The positive displacement vane pump for pumping of LOX and LH2 is investigated. This effort has included: (1) a testing program in which pump performance was investigated for differing pump clearances and for differing pump materials while pumping LN2, LOX, and LH2; and (2) an analysis effort, in which a comprehensive pump performance analysis computer code was developed and exercised. An overview of the theoretical framework of the performance analysis computer code is presented, along with a summary of analysis results. Experimental results are presented for pump operating in liquid nitrogen. Included are data on the effects on pump performance of pump clearance, speed, and pressure rise. Pump suction performance is also presented.

Microfluidic T-form mixer utilizing switching electroosmotic flow.

PubMed

Lin, Che-Hsin; Fu, Lung-Ming; Chien, Yu-Sheng

2004-09-15

This paper presents a microfluidic T-form mixer utilizing alternatively switching electroosmotic flow. The microfluidic device is fabricated on low-cost glass slides using a simple and reliable fabrication process. A switching DC field is used to generate an electroosmotic force which simultaneously drives and mixes the fluid samples. The proposed design eliminates the requirements for moving parts within the microfluidic device and delicate external control systems. Two operation modes, namely, a conventional switching mode and a novel pinched switching mode, are presented. Computer simulation is employed to predict the mixing performance attainable in both operation modes. The simulation results are then compared to those obtained experimentally. It is shown that a mixing performance as high as 97% can be achieved within a mixing distance of 1 mm downstream from the T-junction when a 60 V/cm driving voltage and a 2-Hz switching frequency are applied in the pinched switching operation mode. This study demonstrates how the driving voltage and switching frequency can be optimized to yield an enhanced mixing performance. The novel methods presented in this study provide a simple solution to mixing problems in the micro-total-analysis-systems field.

Characterization of mixing in an electroosmotically stirred continuous micro mixer

NASA Astrophysics Data System (ADS)

Beskok, Ali

2005-11-01

We present theoretical and numerical studies of mixing in a straight micro channel with zeta potential patterned surfaces. A steady pressure driven flow is maintained in the channel in addition to a time dependent electroosmotic flow, generated by a stream-wise AC electric field. The zeta potential patterns are placed critically in the channel to achieve spatially asymmetric time-dependent flow patterns that lead to chaotic stirring. Fixing the geometry, we performed parametric studies of passive particle motion that led to generation of Poincare sections and characterization of chaotic strength by finite time Lyapunov exponents. The parametric studies were performed as a function of the Womersley number (normalized AC frequency) and the ratio of Poiseuille flow and electroosmotic velocities. After determining the non-dimensional parameters that led to high chaotic strength, we performed spectral element simulations of species transport and mixing at high Peclet numbers, and characterized mixing efficiency using the Mixing Index inverse. Mixing lengths proportional to the natural logarithm of the Peclet number are reported. Using the optimum non-dimensional parameters and the typical magnitudes involved in electroosmotic flows, we were able to determine the physical dimensions and operation conditions for a prototype micro-mixer.

The Upper Atmosphere Research Satellite microwave limb sounder instrument

NASA Technical Reports Server (NTRS)

Barath, F. T.; Chavez, M. C.; Cofield, R. E.; Flower, D. A.; Frerking, M. A.; Gram, M. B.; Harris, W. M.; Holden, J. R.; Jarnot, R. F.; Kloezeman, W. G.

1993-01-01

The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric ClO, O3, H2O, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centred near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183- and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for 'total power' measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met.

Cold Aero Performance of a Two-Dimensional Mixer Ejector Nozzle

NASA Technical Reports Server (NTRS)

Balan, C.

2005-01-01

Since 1986, NASA and the U.S. aerospace industry have been assessing the economic viability and environmental acceptability of a second-generation supersonic civil transport, or High Speed Civil Transport (HSCT). Environmental acceptability in terms of airport community noise and economic viability are critical elements in this endeavor. Development of a propulsion system that satisfies strict airport noise regulations (FAR36 Stage III levels), at acceptable performance and weight, is critical to the success of any HSCT program. Two-dimensional mixer-ejector (2DME) exhaust systems are one approach in achieving this goal. In support of HSCT development, GEAE (GE Aircraft Engines), under contract to the NASA Glenn Research Center, conducted this test program at the NASA Langley 16 ft transonic wind tunnel to evaluate the cold aerodynamic performance aspects of the 2DME exhaust system concept. The effects of SAR (SAR, suppressor area ratio, = mixed-flow area/primary nozzle throat area), MAR (MAR = overall exhaust system exit/mixing-plane area), flap length, CER (suppressor chute expansion ratio), chute alignment, and free stream Mach number were investigated on a 1/11th cold aerodynamic scale model of a 2DME exhaust system.

The Upper Atmosphere Research Satellite microwave limb sounder instrument

NASA Astrophysics Data System (ADS)

Barath, F. T.; Chavez, M. C.; Cofield, R. E.; Flower, D. A.; Frerking, M. A.; Gram, M. B.; Harris, W. M.; Holden, J. R.; Jarnot, R. F.; Kloezeman, W. G.

1993-06-01

The microwave limb sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is the first satellite experiment using limb sounding techniques at microwave frequencies. Primary measurement objectives are stratospheric ClO, O3, H2O, temperature, and pressure. Measurements are of thermal emission: all are performed simultaneously and continuously and are not degraded by ice clouds or volcanic aerosols. The instrument has a 1.6-m mechanically scanning antenna system and contains heterodyne radiometers in spectral bands centred near 63, 183, and 205 GHz. The radiometers operate at ambient temperature and use Schottky-diode mixers with local oscillators derived from phase-locked Gunn oscillators. Frequency tripling by varactor multipliers generates the 183- and 205-GHz local oscillators, and quasi-optical techniques inject these into the mixers. Six 15-channel filter banks spectrally resolve stratospheric thermal emission lines and produce an output spectrum every 2 s. Thermal stability is sufficient for 'total power' measurements which do not require fast chopping. Radiometric calibration, consisting of measurements of cold space and an internal target, is performed every 65-s limb scan. Instrument in-orbit performance has been excellent, and all objectives are being met.

75 FR 65378 - Notice of Receipt of Complaint; Solicitation of Comments Relating to the Public Interest

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-22

... Certain Electronic Device Mixer Apparatus for use in the Audio Disc-Jockey Industry, DN 2761; the... within the United States after importation of certain electronic device mixer apparatus for use in the...

A Novel Split-Waveguide Mount Design For MM and SubMM wave frequency multipliers and Harmonic Mixers

NASA Technical Reports Server (NTRS)

Raisanen, Anti V.; Choudhury, Debabani; Dengler, Robert J.; Oswald, John E.; Siegel, Peter H.

1993-01-01

A novel split-waveguide mount for millimeter and submillimeter wave frequency multipliers and harmonic mixers is presented. It consists of only two pieces, block halves, which are mirror images of each other.

VERIFICATION TESTING OF HIGH-RATE MECHANICAL INDUCTION MIXERS FOR CHEMICAL DISINFECTANTS

EPA Science Inventory

This paper describes the results of verification testing of mechanical induction mixers for dispersion of chemical disinfectants in wet-weather flow (WWF) conducted under the U.S. Environmental Protection Agency's Environmental Technology Verification (ETV) WWF Pilot Program. Th...

High linearity current communicating passive mixer employing a simple resistor bias

NASA Astrophysics Data System (ADS)

Rongjiang, Liu; Guiliang, Guo; Yuepeng, Yan

2013-03-01

A high linearity current communicating passive mixer including the mixing cell and transimpedance amplifier (TIA) is introduced. It employs the resistor in the TIA to reduce the source voltage and the gate voltage of the mixing cell. The optimum linearity and the maximum symmetric switching operation are obtained at the same time. The mixer is implemented in a 0.25 μm CMOS process. The test shows that it achieves an input third-order intercept point of 13.32 dBm, conversion gain of 5.52 dB, and a single sideband noise figure of 20 dB.

The spurious response of microwave photonic mixer

NASA Astrophysics Data System (ADS)

Xiao, Yongchuan; Zhong, Guoshun; Qu, Pengfei; Sun, Lijun

2018-02-01

Microwave photonic mixer is a potential solution for wideband information systems due to the ultra-wide operating bandwidth, high LO-to-RF isolation, the intrinsic immunity to electromagnetic interference, and the compatibility with exsiting microwave photonic transmission systems. The spurious response of microwave photonic mixer cascading in series a pair of Mach-Zehnder interferometric intensity modulators has been simulated and analyzed in this paper. The low order spurious products caused by the nonlinearity of modulators are non-negligible, and the proper IF frequency and accurate bias-controlling are of great importance to mitigate the impact of spurious products.

A corner-reflector mixer mount for far infrared wavelengths.

PubMed

Zmuidzinas, J; Betz, A L; Boreiko, R T

1989-01-01

A new type of corner-reflector mixer mount, which has the advantages of ease of fabrication and assembly as well as frequency versatility, has been designed and constructed. The mixer works with arbitrary antenna lengths > or = 4 lambda with the reflector to antenna spacing adjusted to give a strong and symmetric central lobe. The predicted response patterns have been experimentally verified for various antenna lengths and operating frequencies between 800 and 2000 GHz. An important design feature is the incorporation of a microstrip matching network which eliminates IF impedance mismatch and provides mechanical isolation of the whisker antenna.

Influence of technical parameters of disk-shaped reactor on productivity of heat treatment of crushed wood

NASA Astrophysics Data System (ADS)

Safin, R. R.; Khasanshin, R. R.; Mukhametzyanov, S. R.

2018-03-01

The existing installations for heat treatment of the crushed wood are analyzed. The technology of heat treatment of the crushed wood in the devices of disk-shaped type is offered. The results of modeling for the purpose of determination of interrelation of the key design and technological parameters of the disk-shaped device are presented. It is established that the major factors, affecting duration of stay of the material in a device, are the speed of rotation of the mixer, the number of mixers and the number of rakes on the mixer.

The role of Mixer in patterning the early Xenopus embryo.

PubMed

Kofron, Matt; Wylie, Chris; Heasman, Janet

2004-05-01

The transcription factor VegT, is required in early Xenopus embryos for the formation of both the mesoderm and endoderm germ layers. Inherited as a maternal mRNA localized only in vegetal cells, VegT activates the transcription of a large number of transcription factors, as well as signaling ligands that induce cells in the vegetal mass to form endoderm, and the marginal zone to form mesoderm. It is important now to understand the extent to which transcription factors downstream of VegT play individual, or overlapping, roles in the specification and patterning of the endoderm and mesoderm. In addition, it is important to understand the mechanism that specifies the boundary between endoderm and mesoderm. One of the downstream targets of VegT, the homeodomain protein Mixer, is expressed at high levels at the mesoderm/endoderm boundary at the late blastula stage. We therefore examined its functions by blocking its translation using morpholino oligos. In Mixer-depleted embryos, the expression of many signaling ligands and transcription factors was affected. In particular, we found that the expression of several genes, including several normally expressed in mesoderm, was upregulated. Functional assays of Mixer-depleted vegetal cells showed that they have increased mesoderm-inducing activity. This demonstrates that Mixer plays an essential role in controlling the amount of mesoderm induction by the vegetal cells.

Wide-band operation of quasi-optical distributed superconductor/insulator/superconductor mixers with epitaxial NbN/AlN/NbN junctions

NASA Astrophysics Data System (ADS)

Kohjiro, S.; Shitov, S. V.; Wang, Z.; Uzawa, Y.; Miki, S.; Kawakami, A.; Shoji, A.

2004-05-01

For the optimum design of integrated receivers operating above the gap frequency of Nb, we have designed, fabricated and tested NbN-based quasi-optical superconductor/insulator/superconductor (SIS) mixers. The mixer chip incorporates a resonant half-wavelength epitaxial NbN/AlN/NbN junction, a twin-slot antenna and their coupling circuits. We adopted two kinds of coupling circuit between the antenna and the SIS junction: one is an in-phase feed with a length of 95 µm and the other is an anti-phase feed of 30 µm length. It was found that the anti-phase mixer reveals a 3 dB bandwidth of 43% of the centre frequency; the uncorrected double-sideband receiver noise temperature TRX = 691 K at 0.91 THz and TRX = 844 K at 0.80 THz, while 17% and TRX = 1250 K at 0.79 THz for the in-phase version. Possible reasons for this difference are discussed, which could be transmission loss and its robustness with respect to the variation of junction parameters. These experimental results suggest the NbN-based distributed mixer with the anti-phase feed is a better candidate for wide-band integrated receivers operating above 0.7 THz.

THz instrumentation for the Herschel Space Observatory's heterodyne instrument for far infrared

NASA Astrophysics Data System (ADS)

Pearson, John C.; Mehdi, Imran; Ward, John S.; Maiwald, Frank W.; Ferber, Robert R.; LeDuc, Henry G.; Schlecht, Erich T.; Gill, John J.; Hatch, William A.; Kawamura, Jonathan H.; Stern, Jeffrey A.; Gaier, Todd C.; Samoska, Lorene A.; Weinreb, Sander; Bumble, Bruce; Pukala, David M.; Javadi, Hamid H.; Finamore, Bradley P.; Lin, Robert H.; Dengler, Robert J.; Velebir, James R.; Luong, Edward M.; Tsang, Raymond; Peralta, Alejandro; Wells, Mary; Chun, William; Zmuidzinas, Jonas; Karpov, Alexandre; Phillips, Thomas; Miller, David; Maestrini, Alain E.; Erickson, Neal; Swift, Gerald; Liao, K. T.; Paquette, Michael

2004-10-01

The Heterodyne Instrument for Far Infrared (HIFI) on ESA's Herschel Space Observatory utilizes a variety of novel RF components in its five SIS receiver channels covering 480- 1250 GHz and two HEB receiver channels covering 1410-1910 GHz. The local oscillator unit will be passively cooled while the focal plane unit is cooled by superfluid helium and cold helium vapors. HIFI employs W-band GaAs amplifiers, InP HEMT low noise IF amplifiers, fixed tuned broadband planar diode multipliers, high power W-band Isolators, and novel material systems in the SIS mixers. The National Aeronautics and Space Administration through the Jet Propulsion Laboratory is managing the development of the highest frequency (1119-1250 GHz) SIS mixers, the local oscillators for the three highest frequency receivers as well as W-band power amplifiers, high power W-band isolators, varactor diode devices for all high frequency multipliers and InP HEMT components for all the receiver channels intermediate frequency amplifiers. The NASA developed components represent a significant advancement in the available performance. This paper presents an update of the performance and the current state of development.

THz Instrumentation for the Herschel Space Observatory's Heterodyne Instrument for Far Infrared

NASA Technical Reports Server (NTRS)

Pearson, J. C.; Mehdi, I.; Ward, J. S.; Maiwald, F.; Ferber, R. R.; Leduc, H. G.; Schlecht, E. T.; Gill, J. J.; Hatch, W. A.; Kawamura, J. H.;

40 CFR 63.9500 - What emission limitations must I meet?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Friction Materials Manufacturing..., reconstructed, or existing large solvent mixer at your friction materials manufacturing facility, you must limit...) For each new, reconstructed, or existing small solvent mixer at your friction materials manufacturing...

40 CFR 63.9500 - What emission limitations must I meet?

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Friction Materials Manufacturing..., reconstructed, or existing large solvent mixer at your friction materials manufacturing facility, you must limit...) For each new, reconstructed, or existing small solvent mixer at your friction materials manufacturing...

40 CFR 63.9500 - What emission limitations must I meet?

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Friction Materials Manufacturing..., reconstructed, or existing large solvent mixer at your friction materials manufacturing facility, you must limit...) For each new, reconstructed, or existing small solvent mixer at your friction materials manufacturing...

VERIFICATION TESTING OF HIGH-RATE MECHANICAL INDUCTION MIXERS FOR CHEMICAL DISINFECTANTS, Oregon

EPA Science Inventory

This paper describes the results of verification testing of mechanical induction mixers for dispersion of chemical disinfectants in wet-weather flow (WWF) conducted under the U.S. Environmental Protection Agency's Environmental Technology Verification (ETV) WWF Pilot Program. Th...

40 CFR 63.9500 - What emission limitations must I meet?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Friction Materials Manufacturing..., reconstructed, or existing large solvent mixer at your friction materials manufacturing facility, you must limit...) For each new, reconstructed, or existing small solvent mixer at your friction materials manufacturing...

16. VIEW OF THE CONCRETE MIXER THAT WAS USED AT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. VIEW OF THE CONCRETE MIXER THAT WAS USED AT THE MERCER MUSEUM AND ON THE INDIAN HOUSE TOWER. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

Quasi-Optical SIS Mixer Development

NASA Technical Reports Server (NTRS)

Zmuidzinas, J.

1997-01-01

This grant supported our ongoing development of sensitive quasi-optical SIS mixers for the submillimeter band. The technology developed under this grant is now being applied to NASA missions, including the NASA/USRA SOFIA airborne observatory and and the ESA/NASA FIRST/Herschel space astronomy mission.

Study of Reactive Melt Processing Behavior of Externally Plasticized Cellulose Acetate in Presence of Isocyanate

PubMed Central

Erdmann, Rafael; Kabasci, Stephan; Kurek, Joanna; Zepnik, Stefan

2014-01-01

Two types of externally plasticized cellulose acetate (CA) were chemically modified using 4,4'-methylene diphenyl diisocyanate (MDI) as crosslinking agent. Crosslinking was performed in the molten state by means of melt mixing in an internal mixer. The viscoelastic properties of the non-crosslinked, externally plasticized CA show typical temperature dependence, similar to conventional thermoplastics. A strong increase in storage modulus is observed with increasing crosslink density indicating that the crosslinked compounds exhibit predominately elastic response. The complex viscosity also increases considerably with increasing crosslink density and does not reach the typical Newtonian plateau at low radial frequencies any more. The viscoelastic properties correlate well with the data recorded online during reactive melt processing in the internal mixer. In comparison to the non-crosslinked CA, the crosslinked compounds show higher glass transition temperature, higher VICAT softening temperatures, improved thermal stability and lower plasticizer evaporation at evaluated temperatures. PMID:28788273

Study of Reactive Melt Processing Behavior of Externally Plasticized Cellulose Acetate in Presence of Isocyanate.

PubMed

Erdmann, Rafael; Kabasci, Stephan; Kurek, Joanna; Zepnik, Stefan

2014-12-04

Two types of externally plasticized cellulose acetate (CA) were chemically modified using 4,4'-methylene diphenyl diisocyanate (MDI) as crosslinking agent. Crosslinking was performed in the molten state by means of melt mixing in an internal mixer. The viscoelastic properties of the non-crosslinked, externally plasticized CA show typical temperature dependence, similar to conventional thermoplastics. A strong increase in storage modulus is observed with increasing crosslink density indicating that the crosslinked compounds exhibit predominately elastic response. The complex viscosity also increases considerably with increasing crosslink density and does not reach the typical Newtonian plateau at low radial frequencies any more. The viscoelastic properties correlate well with the data recorded online during reactive melt processing in the internal mixer. In comparison to the non-crosslinked CA, the crosslinked compounds show higher glass transition temperature, higher VICAT softening temperatures, improved thermal stability and lower plasticizer evaporation at evaluated temperatures.

Modeling and Simulation of a Nuclear Fuel Element Test Section

NASA Technical Reports Server (NTRS)

Moran, Robert P.; Emrich, William

2011-01-01

"The Nuclear Thermal Rocket Element Environmental Simulator" test section closely simulates the internal operating conditions of a thermal nuclear rocket. The purpose of testing is to determine the ideal fuel rod characteristics for optimum thermal heat transfer to their hydrogen cooling/working fluid while still maintaining fuel rod structural integrity. Working fluid exhaust temperatures of up to 5,000 degrees Fahrenheit can be encountered. The exhaust gas is rendered inert and massively reduced in temperature for analysis using a combination of water cooling channels and cool N2 gas injectors in the H2-N2 mixer portion of the test section. An extensive thermal fluid analysis was performed in support of the engineering design of the H2-N2 mixer in order to determine the maximum "mass flow rate"-"operating temperature" curve of the fuel elements hydrogen exhaust gas based on the test facilities available cooling N2 mass flow rate as the limiting factor.

Superconducting terahertz mixer using a transition-edge microbolometer

NASA Technical Reports Server (NTRS)

Prober, D. E.

1993-01-01

We present a new device concept for a mixer element for THz frequencies. This uses a superconducting transition-edge microbridge biased at the center of its superconducting transition near 4.2 K. It is fed from an antenna or waveguide structure. Power from a local oscillator and an RF signal produce a temperature and resulting resistance variation at the difference frequency. The new aspect is the use of a very short bridge in which rapid (less than 0.1 ns) outdiffusion of hot electrons occurs. This gives large intermediate frequency (IF) response. The mixer offers about 4 GHz IF bandwidth, about 80 ohm RF resistive impedance, good match to the IF amplifier, and requires only 1-20 nW of local oscillator power. The upper RF frequency is determined by antenna or waveguide properties. Predicted mixer conversion efficiency is 1/8, and predicted double-sideband receiver noise temperatures are 260 and 90 K for transition widths of 0.1 and 0.5 Tc, respectively.

A novel microfluidic mixer based on dual-hydrodynamic focusing for interrogating the kinetics of DNA-protein interaction.

PubMed

Li, Ying; Xu, Fei; Liu, Chao; Xu, Youzhi; Feng, Xiaojun; Liu, Bi-Feng

2013-08-21

Kinetic measurement of biomacromolecular interaction plays a significant role in revealing the underlying mechanisms of cellular activities. Due to the small diffusion coefficient of biomacromolecules, it is difficult to resolve the rapid kinetic process with traditional analytical methods such as stopped-flow or laminar mixers. Here, we demonstrated a unique continuous-flow laminar mixer based on microfluidic dual-hydrodynamic focusing to characterize the kinetics of DNA-protein interactions. The time window of this mixer for kinetics observation could cover from sub-milliseconds to seconds, which made it possible to capture the folding process with a wide dynamic range. Moreover, the sample consumption was remarkably reduced to <0.55 μL min⁻¹, over 1000-fold saving in comparison to those reported previously. We further interrogated the interaction kinetics of G-quadruplex and the single-stranded DNA binding protein, indicating that this novel micromixer would be a useful approach for analyzing the interaction kinetics of biomacromolecules.

Electrospray micromixer chip for on-line derivatization and kinetic studies.

PubMed

Abonnenc, Mélanie; Dayon, Loïc; Perruche, Brice; Lion, Niels; Girault, Hubert H

2008-05-01

An electrospray microchip for mass spectrometry comprising an integrated passive mixer to carry out on-chip chemical derivatizations is described. The microchip fabricated using UV-photoablation is composed of two microchannels linked together by a liquid junction. Downstream of this liquid junction, a mixing unit made of parallel oblique grooves is integrated to the microchannel in order to create flow perturbations. Several mixer designs are evaluated. The mixer efficiency is investigated both by fluorescence study and mass spectrometric monitoring of the tagging reaction of cysteinyl peptides with 1,4-benzoquinone. The comparisons with a microchip without a mixing unit and a kinetic model are used to assess the efficiency of the mixer showing tagging kinetics close to that of bulk reactions in an ideally mixed reactor. As an ultimate application, the electrospray micromixer is implemented in a LC-MS workflow. On-line derivatization of albumin tryptic peptides after a reversed-phase separation and counting of their cysteines drastically enhance the protein identification.

Noise tests of a model engine-over-the-wing STOL configuration using a multijet nozzle with deflector

NASA Technical Reports Server (NTRS)

Olsen, W. A.; Friedman, R.

1973-01-01

Noise data were obtained with a small scale model stationary STOL configuration that used an eight lobe mixer nozzle with deflector mounted above a 32-cm-chord wing section. The factors varied to determine their effect upon the noise were wing flap angle, nozzle shape, nozzle location, deflector configuration, and jet velocity. The noise from the mixer nozzle model was compared to the noise from a model using a circular nozzle of the same area. The mixer nozzle model was quieter at the low to middle frequencies, while the circular nozzle was quieter at high frequencies. The perceived noise level (PNL) was calculated for an aircraft 10 times larger than the model. The PNL at 500 feet for the mixer nozzle turned out to be within 1 db of the PNL for the circular nozzle. For some configurations at highly directional broadband noise, which could be eliminated by changes in nozzle and/or deflector location, occurred below the wing.

A compact D-band monolithic APDP-based sub-harmonic mixer

NASA Astrophysics Data System (ADS)

Zhang, Shengzhou; Sun, Lingling; Wang, Xiang; Wen, Jincai; Liu, Jun

2017-11-01

The paper presents a compact D-band monolithic sub-harmonic mixer (SHM) with 3 μm planar hyperabrupt schottky-varactor diodes offered by 70 nm GaAs mHEMT technology. According to empirical equivalent-circuit models, a wide-band large signal equivalent circuit model of the diode is proposed. Based on the extracted model, the mixer is implemented and optimized with a shunt-mounted anti-parallel diode pair (APDP) to fulfill the sub-harmonic mixing mechanism. Furthermore, a modified asymmetric three-transmission-line coupler is devised to achieve high-level coupling and minimize the chip size. The measured results show that the conversion gain varies between -13.9 dB and -17.5 dB from 110 GHz to 145 GHz, with a local oscillator (LO) power level of 14 dBm and an intermediate frequency (IF) of 1 GHz. The total chip size including probe GSG pads is 0.57 × 0.68mm2. In conclusion, the mixer exhibits outstanding figure-of-merits.

Qualification test of the Ross Double Planetary Mixer

NASA Technical Reports Server (NTRS)

Lueders, Kurt F.

1993-01-01

This test report describes the qualification test of the Ross Double Planetary Mixer used to mix room temperature vulcanized (RTV) silicone (Dow Corning 90-006-2) for the redesigned solid rocket motor (RSRM) nozzle joints. Testing was completed 18 June 1993 in the M-113A Nozzle Fabrication Facility at Thiokol Corporation, Space Operations, Brigham City, Utah. The Ross mixer provides better mixing and better control on temperature and humidity, resulting in better quality RTV and a longer usable pot life. The test began on 3 May 1993 and was stopped due to operator error during the tensile strength and elongation testing. Specimens were ruined without gathering any useful data. A 'no test' was declared, the problem was remedied, and the test was re-run with MSFC approval. The test was run and all pass/fail criteria were met, most with a considerable margin. The Ross Double Planetary Mixer met all certification objectives and is recommended for immediate use for mixing RTV silicone for RSRM nozzle joints.

A three-dimensional turbulent compressible flow model for ejector and fluted mixers

NASA Technical Reports Server (NTRS)

Rushmore, W. L.; Zelazny, S. W.

1978-01-01

A three dimensional finite element computer code was developed to analyze ejector and axisymmetric fluted mixer systems whose flow fields are not significantly influenced by streamwise diffusion effects. A two equation turbulence model was used to make comparisons between theory and data for various flow fields which are components of the ejector system, i.e., (1) turbulent boundary layer in a duct; (2) rectangular nozzle (free jet); (3) axisymmetric nozzle (free jet); (4) hypermixing nozzle (free jet); and (5) plane wall jet. Likewise, comparisons of the code with analytical results and/or other numerical solutions were made for components of the axisymmetric fluted mixer system. These included: (1) developing pipe flow; (2) developing flow in an annular pipe; (3) developing flow in an axisymmetric pipe with conical center body and no fluting and (4) developing fluted pipe flow. Finally, two demonstration cases are presented which show the code's ability to analyze both the ejector and axisymmetric fluted mixers.

Artificial sweeteners, caffeine, and alcohol intoxication in bar patrons.

PubMed

Rossheim, Matthew E; Thombs, Dennis L

2011-10-01

Previous laboratory research on alcohol absorption has found that substitution of artificially sweetened alcohol mixers for sucrose-based mixers has a marked effect on the rate of gastric emptying, resulting in elevated blood alcohol concentrations. Studies conducted in natural drinking settings, such as bars, have indicated that caffeine ingestion while drinking is associated with higher levels of intoxication. To our knowledge, research has not examined the effects of alcohol mixers that contain both an artificial sweetener and caffeine, that is, diet cola. Therefore, we assessed the event-specific association between diet cola consumption and alcohol intoxication in bar patrons. We sought to determine whether putative increases in blood alcohol, produced by accelerated gastric emptying following diet cola consumption, as identified in the laboratory, also appear in a natural setting associated with impaired driving. We conducted a secondary analysis of data from 2 nighttime field studies that collected anonymous information from 413 randomly selected bar patrons in 2008 and 2010. Data sets were merged and recoded to distinguish between energy drink, regular cola, diet cola, and noncaffeinated alcohol mixers. Caffeinated alcohol mixers were consumed by 33.9% of the patrons. Cola-caffeinated mixed drinks were much more popular than those mixed with energy drinks. A large majority of regular cola-caffeinated mixed drink consumers were men (75%), whereas diet cola-caffeinated mixed drink consumers were more likely to be women (57%). After adjusting for the number of drinks consumed and other potential confounders, number of diet cola mixed drinks had a significant association with patron intoxication (β = 0.233, p < 0.0001). Number of drinks mixed with regular (sucrose-sweetened) cola and energy drinks did not have significant associations with intoxication (p > 0.05). Caffeine's effect on intoxication may be most pronounced when mixers are artificially sweetened, that is, lack sucrose which slows the rate of gastric emptying of alcohol. Risks associated with on-premise drinking may be reduced by greater attention given to types of mixers, particularly diet colas. Copyright © 2011 by the Research Society on Alcoholism.

670-GHz Down- and Up-Converting HEMT-Based Mixers

NASA Technical Reports Server (NTRS)

Schlecht, Enrich T.; Chattopadhyay, Goutam; Lin, Robert H.; Sin, Seth; Deal, William; Rodriquez, Bryan; Bayuk, Brian; Leong, Kevin; Mei, Gerry

2012-01-01

A large category of scientific investigation takes advantage of the interactions of signals in the frequency range from 300 to 1,000 GHz and higher. This includes astronomy and atmospheric science, where spectral observations in this frequency range give information about molecular abundances, pressures, and temperatures of small-sized molecules such as water. Additionally, there is a minimum in the atmospheric absorption at around 670 GHz that makes this frequency useful for terrestrial imaging, radar, and possibly communications purposes. This is because 670 GHz is a good compromise for imaging and radar applications between spatial resolution (for a given antenna size) that favors higher frequencies, and atmospheric losses that favor lower frequencies. A similar trade-off applies to communications link budgets: higher frequencies allow smaller antennas, but incur a higher loss. All of these applications usually require converting the RF (radio frequency) signal at 670 GHz to a lower IF (intermediate frequency) for processing. Further, transmitting for communication and radar generally requires up-conversion from IF to the RF. The current state-of-the-art device for performing the frequency conversion is based on Schottky diode mixers for both up and down conversion in this frequency range for room-temperature operation. Devices that can operate at room temperature are generally required for terrestrial, military, and planetary applications that cannot tolerate the mass, bulk, and power consumption of cryogenic cooling. The technology has recently advanced to the point that amplifiers in the region up to nearly 1,000 GHz are feasible. Almost all of these have been based on indium phosphide pseudomorphic high-electron mobility transistors (pHEMTs), in the form of monolithic microwave integrated circuits (MMICs). Since the processing of HEMT amplifiers is quite differ en t from that of Schottky diodes, use of Schottky mixers requires separate MMICs for the mixers and amplifiers. Fabrication of all the down-/up-conversion circuitry on single MMICs, using a ll-HEMT circuits, would constitute a major advance in circuit simplicity.

Method of making compost and spawned compost, mushroom spawn and generating methane gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoller, B.B.

1981-04-28

Newly designed ribbon-type mixers provide an improved method for making composts, aerating composts, growing mushroom spawn, generating methane gas, and filling conveyors in the mushroom-growing industry. The mixers may be the double-ribbon type for purely mixing operations or the single-ribbon type for moving the material from one place to another. Both types can operate under pressure. In preparing compost for mushroom growing, operators can first use the airtight mixers for a preliminary anaerobic fermentation to produce methane, then by changing the atmosphere to an oxidizing one, complete the compost preparation under the necessary aerobic conditions.

A User's Guide for the Differential Reduced Ejector/Mixer Analysis "DREA" Program. 1.0

NASA Technical Reports Server (NTRS)

DeChant, Lawrence J.; Nadell, Shari-Beth

1999-01-01

A system of analytical and numerical two-dimensional mixer/ejector nozzle models that require minimal empirical input has been developed and programmed for use in conceptual and preliminary design. This report contains a user's guide describing the operation of the computer code, DREA (Differential Reduced Ejector/mixer Analysis), that contains these mathematical models. This program is currently being adopted by the Propulsion Systems Analysis Office at the NASA Glenn Research Center. A brief summary of the DREA method is provided, followed by detailed descriptions of the program input and output files. Sample cases demonstrating the application of the program are presented.

Terahertz Heterodyne Receiver with an Electron-Heating Mixer and a Heterodyne Based on the Quantum-Cascade Laser

NASA Astrophysics Data System (ADS)

Seliverstov, S. V.; Anfertyev, V. A.; Tretyakov, I. V.; Ozheredov, I. A.; Solyankin, P. M.; Revin, L. S.; Vaks, V. L.; Rusova, A. A.; Goltsman, G. N.; Shkurinov, A. P.

2017-12-01

We study characteristics of the laboratory prototype of a terahertz heterodyne receiver with an electron-heating mixer and a heterodyne based on the quantum-cascade laser. The results obtained demonstrate the possibility to use this receiver as a basis for creation of a high-sensitivity terahertz spectrometer, which can be used in many basic and practical applications. A significant advantage of this receiver will be the possibility of placing the mixer and heterodyne in the same cryostat, which will reduce the device dimensions considerably. The obtained experimental results are analyzed, and methods of optimizing the parameters of the receiver are proposed.

Factors which influence the behavior of turbofan forced mixer nozzles

NASA Technical Reports Server (NTRS)

Anderson, B. H.; Povinelli, L. A.

1981-01-01

A finite difference procedure was used to compute the mixing for three experimentally tested mixer geometries. Good agreement was obtained between analysis and experiment when the mechanisms responsible for secondary flow generation were properly modeled. Vorticity generation due to flow turning and vorticity generated within the centerbody lobe passage were found to be important. Results are presented for two different temperature ratios between fan and core streams and for two different free stream turbulence levels. It was concluded that the dominant mechanisms in turbofan mixers is associated with the secondary flows arising within the lobe region and their development within the mixing section.

This photocopy of an engineering drawing shows the BakerPerkins 150gallon ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

This photocopy of an engineering drawing shows the Baker-Perkins 150-gallon mixer installation in the building. Austin, Field & Fry, Architects Engineers, 22311 West Third Street, Los Angeles 57, California: Edwards Test Station Complex, Jet Propulsion Laboratory, California Institute of Technology, Edwards Air Force Base, Edwards, California: "150 Gallon Mixer System Bldg. E-34, Plans, Sections & Details," drawing no. E34/6-0, 10 July 1963. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering: engineering drawings of structures at JPL Edwards Facility. Drawings on file at JPL Plant Engineering, Pasadena, California - Jet Propulsion Laboratory Edwards Facility, Mixer, Edwards Air Force Base, Boron, Kern County, CA

Liquid/Gas Flow Mixers

NASA Technical Reports Server (NTRS)

Fabris, Gracio

1994-01-01

Improved devices mix gases and liquids into bubbly or foamy flows. Generates flowing, homogeneous foams or homogeneous dispersions of small, noncoalescing bubbles entrained in flowing liquids. Mixers useful in liquid-metal magnetohydrodynamic electric-power generator, froth flotation in mining industry, wastewater treatment, aerobic digestion, and stripping hydrocarbon contaminants from ground water.

Variable volume combustor

DOEpatents

Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

2017-01-17

The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

Development of hot-electron THz bolometric mixers using MgB2 thin films

NASA Astrophysics Data System (ADS)

Cunnane, Daniel; Kawamura, Jonathan; Karasik, Boris S.; Wolak, Matthaeus A.; Xi, X. X.

2014-07-01

Terahertz high-resolution spectroscopy of interstellar molecular clouds greatly relies on hot-electron superconducting bolometric (HEB) mixers. Current state-of-the-art receivers use mixer devices made from ultrathin (~ 3-5 nm) films of NbN with critical temperature ~ 9-11 K. Such mixers have been deployed on a number of groundbased, suborbital, and orbital platforms including the HIFI instrument on the Hershel Space Observatory. Despite its good sensitivity and well-established fabrication process, the NbN HEB mixer suffers from the narrow intermediate frequency (IF) bandwidth ~ 2-3 GHz and is limited to operation at liquid Helium temperature. As the heterodyne receivers are now trending towards "high THz" frequencies, the need in a larger IF bandwidth becomes more pressing since the same velocity resolution for a Doppler shifted line at 5 THz requires a 5-times greater IF bandwidth than at 1 THz. Our work is focusing on the realization of practical HEB mixers using ultrathin (10-20 nm) MgB2 films. They are prepared using a Hybrid Physical-Chemical Vapor Deposition (HPCVD) process yielding ultrathin films with critical temperature ~ 37-39 K. The expectation is that the combination of small thickness, high acoustic phonon transparency at the interface with the substrate, and very short electron-phonon relaxation time may lead to IF bandwidth ~ 10 GHz or even higher. SiC continues to be the most favorable substrate for MgB2 growth and as a result, a study has been conducted on the transparency of SiC at THz frequencies. FTIR measurements show that semi-insulating SiC substrates are at least as transparent as Si up to 2.5 THz. Currently films are passivated using a thin (10 nm) SiO2 layer which is deposited ex-situ via RF magnetron sputtering. Micron-sized spiral antenna-coupled HEB mixers have been fabricated using MgB2 films as thin as 10 nm. Fabrication was done using contact UV lithography and Ar Ion milling, with E-beam evaporated Au films deposited for the antenna. Measurements have been carried out on these devices in the DC, Microwave, and THz regimes. The devices are capable of mixing signals above 20 K indicating that operation may be possible using a cryogen-free cooling system. We will report the results of all measurements taken to indicate the local oscillator power requirements and the IF bandwidth of MgB2 HEB mixers.

Influence of Geometry and Flow Variations on NO Formation in the Quick Mixer of a Staged Combustor

NASA Technical Reports Server (NTRS)

Hatch, M. S.; Sowa, W. A.; Samuelsen, G. S.; Holdeman, J. D.

1995-01-01

Staged combustion, such as Rich-Burn/Quick-Mix/Lean-Burn (RQL), is a viable strategy to meet nitric oxide (NO) emission goals for both stationary and propulsion gas turbine engines. A critical element of the design is the quick mixer section where the potential for NO production is high. While numerical calculations of the quick mixer under reacting conditions have been conducted, the hostile environment and lack of appropriate diagnostics have, to date, precluded experimental probing of the reacting case. As an alternative to understanding the effect of geometry and flow variations on the production of NO in the quick mixer, the present paper presents (1) a series of non-reacting parametric studies, and (2) a computational method to extrapolate the results of the non-reacting experiments to reacting conditions. The results show that the rate of NO production is highest in the immediate vicinity of the injection plane. For a given momentum flux ratio between the jets and mainstream, the most effective mixing geometry is that which mixes effectively in both (1) the plane of injection, and (2) the wall regions downstream of the plan of injection. The tailoring of the mixing is key to minimize the NO formed. As a result, the best overall mixer with respect to the minimization of NO production may depend on the system specific characteristics of the particular application.

Measurement and Computation of Supersonic Flow in a Lobed Diffuser-Mixer for Trapped Vortex Combustors

NASA Technical Reports Server (NTRS)

Brankovic, Andreja; Ryder, Robert C., Jr.; Hendricks, Robert C.; Liu, Nan-Suey; Gallagher, John R.; Shouse, Dale T.; Roquemore, W. Melvyn; Cooper, Clayton S.; Burrus, David L.; Hendricks, John A.

2002-01-01

The trapped vortex combustor (TVC) pioneered by Air Force Research Laboratories (AFRL) is under consideration as an alternative to conventional gas turbine combustors. The TVC has demonstrated excellent operational characteristics such as high combustion efficiency, low NO(x) emissions, effective flame stabilization, excellent high-altitude relight capability, and operation in the lean-burn or rich burn-quick quench-lean burn (RQL) modes of combustion. It also has excellent potential for lowering the engine combustor weight. This performance at low to moderate combustor mach numbers has stimulated interest in its ability to operate at higher combustion mach number, and for aerospace, this implies potentially higher flight mach numbers. To this end, a lobed diffuser-mixer that enhances the fuel-air mixing in the TVC combustor core was designed and evaluated, with special attention paid to the potential shock system entering the combustor core. For the present investigation, the lobed diffuser-mixer combustor rig is in a full annular configuration featuring sixfold symmetry among the lobes, symmetry within each lobe, and plain parallel, symmetric incident flow. During hardware cold-flow testing, significant discrepancies were found between computed and measured values for the pitot-probe-averaged static pressure profiles at the lobe exit plane. Computational fluid dynamics (CFD) simulations were initiated to determine whether the static pressure probe was causing high local flow-field disturbances in the supersonic flow exiting the diffuser-mixer and whether shock wave impingement on the pitot probe tip, pressure ports, or surface was the cause of the discrepancies. Simulations were performed with and without the pitot probe present in the modeling. A comparison of static pressure profiles without the probe showed that static pressure was off by nearly a factor of 2 over much of the radial profile, even when taking into account potential axial displacement of the probe by up to 0.25 in. (0.64 cm). Including the pitot probe in the CFD modeling and data interpretation lead to good agreement between measurement and prediction. Graphical inspection of the results showed that the shock waves impinging on the probe surface were highly nonuniform, with static pressure varying circumferentially among the pressure ports by over 10 percent in some cases. As part of the measurement methodology, such measurements should be routinely supplemented with CFD analyses that include the pitot probe as part of the flow-path geometry.

FOREWORD: 6th International Conference on Pumps and Fans with Compressors and Wind Turbines (ICPF2013)

NASA Astrophysics Data System (ADS)

Wu, Yulin; Wang, Zhengwei; Yuan, Shouqi; Shi, Weidong; Liu, Shuhong; Luo, Xingqi; Wang, Fujun

2013-12-01

The 6th International Conference on Pumps and Fans with Compressors and Wind Turbines (ICPF 2013) was held in Beijing, China, 19-22 September 2013, which was jointly organized by Tsinghua University and Jiangsu University. The co-organizers were Zhejiang University, Zhejiang Sci-Tech University, The State Key Laboratory of Hydroscience and Engineering, The State Key Laboratory of Automotive Safety and Energy and Beijing International Science and Technology Cooperation Base for CO2 Utilization and Reduction. The sponsor of the conference was Concepts NREC. The First International Conference on Pumps and Systems (May 1992), the Second International Conference on Pumps and Fans (October 1995), the Third International Conference on Pumps and Fans (October 1998), and the Fourth International Conference on Pumps and Fans (26-29 August 2002) were all held in Beijing and were organized by the late famous Chinese professor on fluid machinery and engineering, Professor Zuyan Mei of Tsinghua University. The conference was interrupted by the death of Professor Mei in 2003. In order to commemorate Professor Mei, the organizing committee of ICPF decided to continue organizing the conference series. The Fifth Conference on Pumps and Systems (2010 ICPF) took place in Hangzhou, Zhejiang Province, China, 18-21 October 2010, and it was jointly organized by Zhejiang University and Tsinghua University. With the development of renewable energy and new energy in China and in the world, some small types of compressor and some types of pump, as well as wind turbines are developing very fast; therefore the ICPF2013 conference included compressors and wind turbines. The theme of the conference was the application of renewable energy of pumps, compressors, fans and blowers. The content of the conference was the basic study, design and experimental study of compressors, fans, blowers and pumps; the CFD application on pumps and fans, their transient behavior, unsteady flows and multi-phase flow; other fluid machinery and devices, such as, wind turbines, turbochargers and reversible pump-turbines, clearance and sealing, jets, filters and mixers; and their engineering application and their system behavior, especially, the application of the renewable energy of pumps, compressors, fans and blowers. The objective of the conference was to provide an opportunity for researchers, engineers and students to report on the latest developments in the fields of pumps, compressors, fans and turbochargers, as well as systems. The participants were encouraged to present their work in progress with a short lead time, and the conference promoted discussion of the problems encountered. The ICPF2013 brought together 191 scientists and researchers from 14 countries, affiliated with universities, technology centers and industrial firms to debate topics related to advanced technologies for pumps and fans, which would enhance the sustainable development of fluid machinery and fluid engineering. The Scientific Committee selected 166 technical papers on the following topics: (i) Principles of Fluid Machinery, (ii) Pumps, (iii) Compressors, Fans and Turbochargers, (iv) Turbines, (v) Cavitation and Multiphase Flow, (vi) Systems and Other Fluid Machinery, and 10 invited plenary and invited session lectures, which were presented at the conference, to be included in the proceedings. All the papers of ICPF2013, which were published in this volume of IOP Conference Series: Materials Science and Engineering, have been peer reviewed through processes administered by the editors of the ICPF2013, those are Yulin Wu, Zhengwei Wang, Shouqi Yuan, Weidong Shi, Shuhong Liu, Xingqi Luo and Fujun Wang. We sincerely hope that the 6th International Conference on Pumps and Fans with Compressors and Wind Turbines is a significant step forward in the worldwide efforts to address the present challenges facing modern fluid machines. Professor Yulin Wu Chairman of the Local Organizing Committee 6th International Conference on Pumps and Fans with Compressors and Wind Turbines (ICPF2013) October 2013 The PDF contains a list of organizers, sponsors and committees.

Multilevel fluidic flow control in a rotationally-driven polyester film microdevice created using laser print, cut and laminate.

PubMed

Ouyang, Yiwen; Li, Jingyi; Phaneuf, Christopher; Riehl, Paul S; Forest, Craig; Begley, Matthew; Haverstick, Doris M; Landers, James P

2016-01-21

This paper presents a simple and cost-effective polyester toner microchip fabricated with laser print and cut lithography (PCL) to use with a battery-powered centrifugal platform for fluid handling. The combination of the PCL microfluidic disc and centrifugal platform: (1) allows parallel aliquoting of two different reagents of four different volumes ranging from nL to μL with an accuracy comparable to a piston-driven air pipette; (2) incorporates a reciprocating mixing unit driven by a surface-tension pump for further dilution of reagents, and (3) is amenable to larger scale integration of assay multiplexing (including all valves and mixers) without substantially increasing fabrication cost and time. For a proof of principle, a 10 min colorimetric assay for the quantitation of the protein level in the human blood plasma samples is demonstrated on chip with a limit of detection of ∼5 mg mL(-1) and coefficient of variance of ∼7%.

A time domain based method for the accurate measurement of Q-factor and resonance frequency of microwave resonators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gyüre, B.; Márkus, B. G.; Bernáth, B.

2015-09-15

We present a novel method to determine the resonant frequency and quality factor of microwave resonators which is faster, more stable, and conceptually simpler than the yet existing techniques. The microwave resonator is pumped with the microwave radiation at a frequency away from its resonance. It then emits an exponentially decaying radiation at its eigen-frequency when the excitation is rapidly switched off. The emitted microwave signal is down-converted with a microwave mixer, digitized, and its Fourier transformation (FT) directly yields the resonance curve in a single shot. Being a FT based method, this technique possesses the Fellgett (multiplex) and Connesmore » (accuracy) advantages and it conceptually mimics that of pulsed nuclear magnetic resonance. We also establish a novel benchmark to compare accuracy of the different approaches of microwave resonator measurements. This shows that the present method has similar accuracy to the existing ones, which are based on sweeping or modulating the frequency of the microwave radiation.« less

Thermodynamic performance of multi-stage gradational lead screw vacuum pump

NASA Astrophysics Data System (ADS)

Zhao, Fan; Zhang, Shiwei; Sun, Kun; Zhang, Zhijun

2018-02-01

As a kind of dry mechanical vacuum pump, the twin-screw vacuum pump has an outstanding pumping performance during operation, widely used in the semiconductor industry. Compared with the constant lead screw (CLS) vacuum pump, the gradational lead screw (GLS) vacuum pump is more popularly applied in recent years. Nevertheless, not many comparative studies on the thermodynamic performance of GLS vacuum pump can be found in the literature. Our study focuses on one type of GLS vacuum pump, the multi-stage gradational lead screw (MGLS) vacuum pump, gives a detailed description of its construction and illustrates it with the drawing. Based on the structural analysis, the thermodynamic procedure is divided into four distinctive processes, including sucking process, transferring (compressing) process, backlashing process and exhausting process. The internal mechanism of each process is qualitatively illustrated and the mathematical expressions of seven thermodynamic parameters are given under the ideal situation. The performance curves of MGLS vacuum pump are plotted by MATLAB software and compared with those of the CLS vacuum pump in the same case. The results can well explain why the MGLS vacuum pump has more favorable pumping performance than the CLS vacuum pump in saving energy, reducing noise and heat dissipation.

An example of a chaotic micromixer: the cross-channel micromixer

NASA Astrophysics Data System (ADS)

Dodge, Arash; Jullien, Marie-Caroline; Lee, Yi-Kuen; Niu, X.; Okkels, Fridolin; Tabeling, Patrick

2004-06-01

In this article dedicated to micromixing, we concentrate here on a particular micromixer - the 'cross-channel micromixer'. This mixer exploits an oscillatory perturbation to induce chaotic trajectories, favoring mixing. We present here theory, numerical simulations and experiments performed on this system. To cite this article: A. Dodge et al., C. R. Physique 5 (2004).

A 1.5 THz hot-electron bolometer mixer operated by a planar diode based local oscillator

NASA Technical Reports Server (NTRS)

Tong, C. Y. E.; Meledin, D.; Blundell, R.; Erickson, N.; Mehdi, I.; Goltsman, G.

2003-01-01

We have developed a 1.5 THz superconducting NbN Hot-Electron Bolometer mixer. It is oprated by an all-solid-state Local Oscillator comprising of a cascade of 4 planar doublers following an MMIC based W-band power amplifier.

29 CFR 1926.702 - Requirements for equipment and tools.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Concrete and Masonry... the ejection system is not to be operated. (b) Concrete mixers. Concrete mixers with one cubic yard... the skip of materials; and (2) Guardrails installed on each side of the skip. (c) Power concrete...

29 CFR 570.62 - Occupations involved in the operation of bakery machines (Order 11).

Code of Federal Regulations, 2013 CFR

2013-07-01

..., or cleaning any horizontal or vertical dough mixer; batter mixer; bread dividing, rounding, or molding machine; dough brake; dough sheeter; combination bread slicing and wrapping machine; or cake cutting band saw. (2) The occupation of setting up or adjusting a cookie or cracker machine. (b...

29 CFR 570.62 - Occupations involved in the operation of bakery machines (Order 11).

Code of Federal Regulations, 2014 CFR

2014-07-01

..., or cleaning any horizontal or vertical dough mixer; batter mixer; bread dividing, rounding, or molding machine; dough brake; dough sheeter; combination bread slicing and wrapping machine; or cake cutting band saw. (2) The occupation of setting up or adjusting a cookie or cracker machine. (b...

29 CFR 570.62 - Occupations involved in the operation of bakery machines (Order 11).

Code of Federal Regulations, 2011 CFR

2011-07-01

..., or cleaning any horizontal or vertical dough mixer; batter mixer; bread dividing, rounding, or molding machine; dough brake; dough sheeter; combination bread slicing and wrapping machine; or cake cutting band saw. (2) The occupation of setting up or adjusting a cookie or cracker machine. (b...

29 CFR 570.62 - Occupations involved in the operation of bakery machines (Order 11).

Code of Federal Regulations, 2012 CFR

2012-07-01

..., or cleaning any horizontal or vertical dough mixer; batter mixer; bread dividing, rounding, or molding machine; dough brake; dough sheeter; combination bread slicing and wrapping machine; or cake cutting band saw. (2) The occupation of setting up or adjusting a cookie or cracker machine. (b...

Analysis of a High-Tc Hot-Electron Superconducting Mixer for Terahertz Applications

NASA Technical Reports Server (NTRS)

Karasik, B. S.; McGrath, W. R.; Gaidis, M. C.

1996-01-01

The prospects of a YBa2Cu3O7(delta)(YBCO) hot-electron bolometer (HEB) mixer for a THz heterodyne receiver is discussed. The modeled device is a submicron bridge made from a 10 nm thick film on a high thermal conductance substrate.

88. VIEW OF THE CONCRETE MIXER THAT WAS USED AT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

88. VIEW OF THE CONCRETE MIXER THAT WAS USED AT THE MERCER MUSEUM AND ON THE INDIAN HOUSE TOWER. SAME VIEW AS PA-107-16. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

7 CFR 58.228 - Dump hoppers, screens, mixers and conveyors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT... DAIRY PRODUCTS 1 General Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Equipment and Utensils § 58.228 Dump hoppers, screens, mixers and conveyors. The product contact...

40 CFR 65.116 - Quality improvement program for pumps.

Code of Federal Regulations, 2014 CFR

2014-07-01

... category of pumps or pump seal technology. The design standards shall specify known critical parameters..., and pump or pump seal designs or technologies that have poorer than average emission performance and... there are superior performing pump or pump seal technologies that are applicable to the service(s...

40 CFR 65.116 - Quality improvement program for pumps.

Code of Federal Regulations, 2013 CFR

2013-07-01

... category of pumps or pump seal technology. The design standards shall specify known critical parameters..., and pump or pump seal designs or technologies that have poorer than average emission performance and... there are superior performing pump or pump seal technologies that are applicable to the service(s...

40 CFR 65.116 - Quality improvement program for pumps.

Code of Federal Regulations, 2012 CFR

2012-07-01

... category of pumps or pump seal technology. The design standards shall specify known critical parameters..., and pump or pump seal designs or technologies that have poorer than average emission performance and... there are superior performing pump or pump seal technologies that are applicable to the service(s...

40 CFR 65.116 - Quality improvement program for pumps.

Code of Federal Regulations, 2011 CFR

2011-07-01

... category of pumps or pump seal technology. The design standards shall specify known critical parameters..., and pump or pump seal designs or technologies that have poorer than average emission performance and... there are superior performing pump or pump seal technologies that are applicable to the service(s...

40 CFR 65.116 - Quality improvement program for pumps.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., and pump or pump seal designs or technologies that have poorer than average emission performance and...), operating conditions, or pump or pump seal designs associated with poorer than average emission performance... poorer than average performance except as provided in paragraph (d)(6)(v) of this section. The trial...

Cryogenic Propellant Long-term Storage With Zero Boil-off

NASA Technical Reports Server (NTRS)

Hedayat, A.; Hastings, L. J.; Sims, J.; Plachta, D. W.

2001-01-01

Significant boil-off losses of cryogenic propellant storage systems in long-duration space mission applications result in additional propellant and large tanks. The zero boil-off (ZBO) concept consists of an active cryo-cooling system integrated with traditional passive thermal insulation. The potential mass reductions with the ZBO concept are Substantial; therefore, further exploration through technology programs has been initiated within NASA. A large-scale demonstration of the ZBO concept has been devised utilizing the Marshall Space Flight Center (MSFC) Multipurpose Hydrogen Test Bed (MHTB) along with a cryo-cooler unit. The cryo-cooler with the MHTB and spraybar recirculation/mixer system in a manner that enables thermal energy removal at a rate that equals the total tank heat leak. The liquid hydrogen is withdrawn from the tank, passed through a heat exchanger, and then the chilled liquid is sprayed back into the tank through a spraybar. The test series will be performed over a 30-40 day period. Tests will be conducted at multiple fill levels and various mixer operational cycles to demonstrate concept viability and to provide benchmark data to be used in analytical model development. In this paper. analytical models for heat flows through the MHTB tank, cryo-cooler performance. and spraybar performance will be presented.

A novel generation of 3D SAR-based passive micromixer: efficient mixing and low pressure drop at a low Reynolds number

NASA Astrophysics Data System (ADS)

Viktorov, Vladimir; Nimafar, Mohammad

2013-05-01

This study introduces a novel generation of 3D splitting and recombination (SAR) passive micromixer with microstructures placed on the top and bottom floors of microchannels called a ‘chain mixer’. Both experimental verification and numerical analysis of the flow structure of this type of passive micromixer have been performed to evaluate the mixing performance and pressure drop of the microchannel, respectively. We propose here two types of chain mixer—chain 1 and chain 2—and compare their mixing performance and pressure drop with other micromixers, T-, o- and tear-drop micromixers. Experimental tests carried out in the laminar flow regime with a low Reynolds number range, 0.083 ≤ Re ≤ 4.166, and image-based techniques are used to evaluate the mixing efficiency. Also, the computational fluid dynamics code, ANSYS FLUENT-13.0 has been used to analyze the flow and pressure drop in the microchannel. Experimental results show that the chain and tear-drop mixer's efficiency is very high because of the SAR process: specifically, an efficiency of up to 98% can be achieved at the tested Reynolds number. The results also show that chain mixers have a lower required pressure drop in comparison with a tear-drop micromixer.

Surface plasmon quantum cascade lasers as terahertz local oscillators.

PubMed

Hajenius, M; Khosropanah, P; Hovenier, J N; Gao, J R; Klapwijk, T M; Barbieri, S; Dhillon, S; Filloux, P; Sirtori, C; Ritchie, D A; Beere, H E

2008-02-15

We characterize a heterodyne receiver based on a surface-plasmon waveguide quantum cascade laser (QCL) emitting at 2.84 THz as a local oscillator, and an NbN hot electron bolometer as a mixer. We find that the envelope of the far-field pattern of the QCL is diffraction-limited and superimposed onto interference fringes, which are similar to those found in narrow double-metal waveguide QCLs. Compared to the latter, a more directional beam allows for better coupling of the radiation power to the mixer. We obtain a receiver noise temperature of 1050 K when the mixer is at 2 K, which, to our knowledge, is the highest sensitivity reported at frequencies beyond 2.5 THz.

All-optical, ultra-wideband microwave I/Q mixer and image-reject frequency down-converter.

PubMed

Gao, Yongsheng; Wen, Aijun; Chen, Wei; Li, Xiaoyan

2017-03-15

An all-optical and ultra-wideband microwave in-phase/quadrature (I/Q) mixer, based on a dual-parallel Mach-Zehnder modulator and a wavelength division multiplexer, is proposed. Due to the simultaneous frequency down-conversion and 360-deg tunable phase shifting in the optical domain, the proposed I/Q mixer has the advantages of high conversion gain and excellent quadrature phase balance (<±1.3 deg⁡) with a wide operating frequency from 10 to 40 GHz. Assisted by an analog or digital intermediate-frequency quadrature coupler, an image-reject frequency down-converter is then implemented, with an image rejection exceeding 50 dB over the working band.

Accurate and rapid micromixer for integrated microfluidic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Dam, R. Michael; Liu, Kan; Shen, Kwang -Fu Clifton

2015-09-22

The invention may provide a microfluidic mixer having a droplet generator and a droplet mixer in selective fluid connection with the droplet generator. The droplet generator comprises first and second fluid chambers that are structured to be filled with respective first and second fluids that can each be held in isolation for a selectable period of time. The first and second fluid chambers are further structured to be reconfigured into a single combined chamber to allow the first and second fluids in the first and second fluid chambers to come into fluid contact with each other in the combined chambermore » for a selectable period of time prior to being brought into the droplet mixer.« less

Design of an Efficient Turbulent Micro-Mixer for Protein Folding Experiments

NASA Astrophysics Data System (ADS)

Inguva, Venkatesh; Perot, Blair

2015-11-01

Protein folding studies require the development of micro-mixers that require less sample, mix at faster rates, and still provide a high signal to noise ratio. Chaotic to marginally turbulent micro-mixers are promising candidates for this application. In this study, various turbulence and unsteadiness generation concepts are explored that avoid cavitation. The mixing enhancements include flow turning regions, flow splitters, and vortex shedding. The relative effectiveness of these different approaches for rapid micro-mixing is discussed. Simulations found that flow turning regions provided the best mixing profile. Experimental validation of the optimal design is verified through laser confocal microscopy experiments. This work is support by the National Science Foundation.

Results From a Parametric Acoustic Liner Experiment Using P and W GEN1 HSR Mixer/Ejector Model

NASA Technical Reports Server (NTRS)

Boyd, Kathleen C.; Wolter, John D.

2004-01-01

This report documents the results of an acoustic liner test performed using a Gen 1 HSR mixer/ejector model installed on the Jet Exit Rig in the Nozzle Acoustic Test Rig in the Aeroacoustic Propulsion Laboratory or NASA Glenn Research Center. Acoustic liner effectiveness and single-component thrust performance results are discussed. Results from 26 different types of single-degree-of-freedom and bulk material liners are compared with each other and against a hardwall baseline. Design parameters involving all aspects of the facesheet, the backing cavity, and the type of bulk material were varied in order to study the effects of these design features on the acoustic impedance, acoustic effectiveness and on nozzle thrust performance. Overall, the bulk absorber liners are more effective at reducing the jet noise than the single-degree-of-freedom liners. Many of the design parameters had little effect on acoustic effectiveness, such as facesheeet hole diameter and honeycomb cell size. A relatively large variation in the impedance of the bulk absorber in a bulk liner is required to have a significant impact on the noise reduction. The thrust results exhibit a number of consistent trends, supporting the validity of this new addition to the facility. In general, the thrust results indicate that thrust performance benefits from increased facesheet thickness and decreased facesheet porosity.

Complex modeling of technological processes in pneumatic mixers for production of dry construction mixtures

NASA Astrophysics Data System (ADS)

Orekhova, T. N.; Nosov, O. A.; Prokopenko, V. S.; Kachaev, A. E.

2018-03-01

The improvement of the design of the pneumatic mixers aimed at the possibility of obtaining homogeneous disperse systems, while the resource and energy saving issues play an important role in the conditions of enterprises that use this type of equipment in their technological chain, is described in the article.

Summary of JAYGO mixing and FSM-1 application of castable inhibitor and liner

NASA Technical Reports Server (NTRS)

Evans, Kurt B.

1990-01-01

Two JAYGO planetary mixers (12 and 42 gallon) are being qualified to mix STW5-3224 liner and STW5-3223 castable inhibitor. These mixers are an integral part of a mix process which allows for safe addition of the asbestos component. An essential part of the engineering evaluation (ETP-0347) of these mixers is the generation of static test fire data. Ultimately, these results will help confirm the adequacy of these mixers for production mixing of liner and inhibitor. (These data are not required for qualification of the Certification Test Plan CTP-0125). The details on the mixing, inhibiting, and sling-lining of JAYGO-mixed castable inhibitor and liner which were applied to the FSM-1 segments are presented. The objectives are the following: (1) to document processing events surrounding the JAYO mixing of castable inhibitor and liner, and the subsequent inhibiting and sling lining onto the FSM-1 segments; and (2) to substantiate the measured properties of these JAYGO-mixed materials (rheological and mechanical) and compare these properties to existing production database.

House microbiotas as sources of lactic acid bacteria and yeasts in traditional Italian sourdoughs.

PubMed

Minervini, Fabio; Lattanzi, Anna; De Angelis, Maria; Celano, Giuseppe; Gobbetti, Marco

2015-12-01

This study aimed at understanding the extent of contamination by lactic acid bacteria (LAB) and yeasts from the house microbiotas during sourdough back-slopping. Besides sourdoughs, wall, air, storage box, dough mixer and flour of four bakeries were analyzed. Based on plate counts, LAB and yeasts dominated the house microbiota. Based on high throughput sequencing of the 16S rRNA genes, flour harbored the highest number of Firmicutes, but only few of them adapted to storage box, dough mixer and sourdough. Lactobacillus sanfranciscensis showed the highest abundance in dough mixer and sourdoughs. Lactobacillus plantarum persisted only in storage box, dough mixer and sourdough of two bakeries. Weissella cibaria also showed higher adaptability in sourdough than in bakery equipment, suggesting that flour is the main origin of this species. Based on 18S rRNA data, Saccharomyces cerevisiae was the dominant yeast in house and sourdough microbiotas, excepted one bakery dominated by Kazachstania exigua. The results of this study suggest that the dominant species of sourdough LAB and yeasts dominated also the house microbiota. Copyright © 2015 Elsevier Ltd. All rights reserved.

Soft Mixer Assignment in a Hierarchical Generative Model of Natural Scene Statistics

PubMed Central

Schwartz, Odelia; Sejnowski, Terrence J.; Dayan, Peter

2010-01-01

Gaussian scale mixture models offer a top-down description of signal generation that captures key bottom-up statistical characteristics of filter responses to images. However, the pattern of dependence among the filters for this class of models is prespecified. We propose a novel extension to the gaussian scale mixture model that learns the pattern of dependence from observed inputs and thereby induces a hierarchical representation of these inputs. Specifically, we propose that inputs are generated by gaussian variables (modeling local filter structure), multiplied by a mixer variable that is assigned probabilistically to each input from a set of possible mixers. We demonstrate inference of both components of the generative model, for synthesized data and for different classes of natural images, such as a generic ensemble and faces. For natural images, the mixer variable assignments show invariances resembling those of complex cells in visual cortex; the statistics of the gaussian components of the model are in accord with the outputs of divisive normalization models. We also show how our model helps interrelate a wide range of models of image statistics and cortical processing. PMID:16999575

Prediction of pump cavitation performance

NASA Technical Reports Server (NTRS)

Moore, R. D.

1974-01-01

A method for predicting pump cavitation performance with various liquids, liquid temperatures, and rotative speeds is presented. Use of the method requires that two sets of test data be available for the pump of interest. Good agreement between predicted and experimental results of cavitation performance was obtained for several pumps operated in liquids which exhibit a wide range of properties. Two cavitation parameters which qualitatively evaluate pump cavitation performance are also presented.

Approaches of truck drivers and non-truck drivers toward reckless on-road behavior.

PubMed

Rosenbloom, Tova; Eldror, Ehud; Shahar, Amit

2009-07-01

The purpose of the study was to compare the reported approaches of truck drivers to those of non-truck drivers toward reckless on-road behaviors. One hundred and sixty-seven adult males, including 70 non-truck drivers, completed the questionnaires voluntarily. The truck drivers were employees of a concrete manufacturing company working at various company plants throughout Israel. Seventy were professional mixer truckers and 27 were tip-truckers. The participants completed the Reckless Driving Self-Report Scale based on Taubman Ben-Ari et al. [Taubman Ben-Ari, O., Florian, V., Mikulincer, M., 1999. The impact of mortality salience on reckless driving: a test of terror management mechanisms. Journal of Personality and Social Psychology 76, 35-45], adapted for truck drivers for this study. It was expected that non-professional, as compared to professional (truck) drivers, would be more permissive regarding reckless driving, since driving risks are less prominent in their daily driving experience. An ANOVA performed on mean reckless-driving scores yielded significant results. The post hoc Schéffe test indicated significantly higher reckless-driving scores for automobile drivers as compared to both mixer-truck driver scores and tip-truck driver scores. In addition, the reckless-driving scores for mixer-truck drivers were significantly higher than the tip-truck driver scores. We discuss various explanations for the findings and consider possible implications for training strategies in organizations as well as for media campaigns focused on mutual safe road use of truck drivers and private vehicle drivers.

Forward Behavioral Modeling of a Three-Way Amplitude Modulator-Based Transmitter Using an Augmented Memory Polynomial

PubMed Central

Chatrath, Jatin; Aziz, Mohsin; Helaoui, Mohamed

2018-01-01

Reconfigurable and multi-standard RF front-ends for wireless communication and sensor networks have gained importance as building blocks for the Internet of Things. Simpler and highly-efficient transmitter architectures, which can transmit better quality signals with reduced impairments, are an important step in this direction. In this regard, mixer-less transmitter architecture, namely, the three-way amplitude modulator-based transmitter, avoids the use of imperfect mixers and frequency up-converters, and their resulting distortions, leading to an improved signal quality. In this work, an augmented memory polynomial-based model for the behavioral modeling of such mixer-less transmitter architecture is proposed. Extensive simulations and measurements have been carried out in order to validate the accuracy of the proposed modeling strategy. The performance of the proposed model is evaluated using normalized mean square error (NMSE) for long-term evolution (LTE) signals. NMSE for a LTE signal of 1.4 MHz bandwidth with 100,000 samples for digital combining and analog combining are recorded as −36.41 dB and −36.9 dB, respectively. Similarly, for a 5 MHz signal the proposed models achieves −31.93 dB and −32.08 dB NMSE using digital and analog combining, respectively. For further validation of the proposed model, amplitude-to-amplitude (AM-AM), amplitude-to-phase (AM-PM), and the spectral response of the modeled and measured data are plotted, reasonably meeting the desired modeling criteria. PMID:29510501

Modeling of diesel/CNG mixing in a pre-injection chamber

NASA Astrophysics Data System (ADS)

Abdul-Wahhab, H. A.; Aziz, A. R. A.; Al-Kayiem, H. H.; Nasif, M. S.

2015-12-01

Diesel engines performance can be improved by adding combustible gases to the liquid diesel. In this paper, the propagation of a two phase flow liquid-gas fuel mixture into a pre-mixer is investigated numerically by computational fluid dynamics simulation. CNG was injected into the diesel within a cylindrical conduit operates as pre-mixer. Four injection models of Diesel-CNG were simulated using ANSYS-FLUENT commercial software. Two CNG jet diameters were used of 1 and 2 mm and the diesel pipe diameter was 9 mm. Two configurations were considered for the gas injection. In the first the gas was injected from one side while for the second two side entries were used. The CNG to Diesel pressure ratio was varied between 1.5 and 3. The CNG to Diesel mass flow ratios were varied between 0.7 and 0.9. The results demonstrate that using double-sided injection increased the homogeneity of the mixture due to the swirl and acceleration of the mixture. Mass fraction, in both cases, was found to increase as the mixture flows towards the exit. As a result, this enhanced mixing is likely to lead to improvement in the combustion performance.

Performance of a Ka-band transponder breadboard for deep-space applications

NASA Technical Reports Server (NTRS)

Mysoor, N. R.; Lane, J. P.; Kayalar, S.; Kermode, A. W.

1995-01-01

This article summarizes the design concepts applied in the development of and advanced Ka-band (34.4 GHz/32 GHz) transponder breadboard for the next generation of space communications systems applications. The selected architecture upgrades the X-band (7.2 GHz/8.4 GHz) deep-space transponder (DST) to provide Da-band up/Ka- and X-band down capability. The Ka-band transponder breadboard incorporates several state-of-the-art components, including sampling mixers, a Ka-band dielectric resonator oscillator, and microwave monolithic integrated circuits (MMICs). The MMICs that were tested in the breadboard include upconverters, downconverters, automatic gain control circuits, mixers, phase modulators, and amplifiers. The measured receiver dynamic range, tracking range, acquisition rate, static phase error, and phase jitter characteristics of the Ka-band breadboard interfaced to the advanced engineering model X-band DST are in good agreement with the expected performance. The results show a receiver tracking threshold of -149 dBm with a dynamic range of 80 dB and a downlink phase jitter of 7 deg rms. The analytical results of phase noise and Allan standard deviation are in good agreement with the experimental results.

Laboratory Investigations in Support of Carbon Dioxide-Limestone Sequestration in the Ocean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dan Golomb; Eugene Barry; David Ryan

2005-11-01

This semi-annual progress reports includes further findings on CO{sub 2}-in-Water (C/W) emulsions stabilized by fine particles. In previous semi-annual reports we described the formation of stable C/W emulsions using pulverized limestone (CaCO{sub 3}), flyash, beach sand, shale and lizardite, a rock rich in magnesium silicate. For the creation of these emulsions we used a High-Pressure Batch Reactor (HPBR) equipped with view windows for illumination and video camera recording. For deep ocean sequestration, a C/W emulsion using pulverized limestone may be the most suitable. (a) Limestone (mainly CaCO{sub 3}) is cheap and plentiful; (b) limestone is innocuous for marine organisms (inmore » fact, it is the natural ingredient of shells and corals); (c) it buffers the carbonic acid that forms when CO{sub 2} dissolves in water. For large-scale sequestration of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion a device is needed that mixes the ingredients, liquid carbon dioxide, seawater, and a slurry of pulverized limestone in seawater continuously, rather than incrementally as in a batch reactor. A practical mixing device is a Kenics-type static mixer. The static mixer has no moving parts, and the shear force for mixing is provided by the hydrostatic pressure of liquid CO{sub 2} and CaCO{sub 3} slurry in the delivery pipes from the shore to the disposal depth. This semi-annual progress report is dedicated to the description of the static mixer and the results that have been obtained using a bench-scale static mixer for the continuous formation of a CO{sub 2}/H{sub 2}O/CaCO{sub 3} emulsion. The static mixer has an ID of 0.63 cm, length 23.5 cm, number of baffles 27. Under pressure, a slurry of CaCO{sub 3} in artificial seawater (3.5% by weight NaCl) and liquid CO{sub 2} are co-injected into the mixer. From the mixer, the resulting emulsion flows into a Jerguson cell with two oblong windows on opposite sides, then it is vented. A fully ported ball valve inserted after the Jerguson cell allows the emulsion to be stopped in the cell. In such a manner the emulsion can be photographed while it is flowing through the cell, or after it has stagnated in the cell. A slurry of 10 g/L CaCO{sub 3} (Sigma Chemicals C-4830 reagent grade) in artificial seawater, co-injected into the static mixer at a rate of 1.5 L/min with liquid CO{sub 2} at a rate of 150 mL/min, at temperature 5-10 C, pressure 10 MPa, produced an emulsion with mean globule diameter in the 70-100 {micro}m range. In a HPBR, using the same materials, proportions, temperature and pressure, mixed with a magnetic stir bar at 1300 rpm, the mean globule diameter is in the 200-300 {micro}m range. Evidently, the static mixer produces an emulsion with smaller globule diameters and narrower distribution of globule diameters than a batch reactor.« less

Microwave phase conjugation using artificial nonlinear microwave surfaces

NASA Astrophysics Data System (ADS)

Chang, Yian

1997-09-01

A new technique is developed and demonstrated to simulate nonlinear materials in the microwave and millimeter wave regime. Such materials are required to extend nonlinear optical techniques into longer wavelength areas. Using an array of antenna coupled mixers as an artificial nonlinear surface, we have demonstrated two-dimensional free space microwave phase conjugation at 10 GHz. The basic concept is to replace the weak nonlinearity of electron distribution in a crystal with the strong nonlinear V-I response of a P-N junction. This demnstration uses a three-wave mixing method with the effective nonlinear susceptibility χ(2) provided by an artificial nonlinear surface. The pump signal at 2ω (20 GHz) can be injected to the mixing elements electrically or optically. Electrical injection was first used to prove the concept of artificial nonlinear surfaces. However, due to the loss and size of microwave components, electrical injection is not practical for an array of artificial nonlinear surfaces, as would be needed in a three-dimensional free space phase conjugation setup. Therefore optical injection was implemented to carry the 2ω microwave pump signal in phase to all mixing elements. In both cases, two-dimensional free space phase conjugation was observed by directly measuring the electric field amplitude and phase distribution. The electric field wavefronts exhibited retro-directivity and auto- correction characteristics of phase conjugation. This demonstration surface also shows a power gain of 10 dB, which is desired for potential communication applications.

Pressure Regulator With Internal Ejector Circulation Pump, Flow and Pressure Measurement Porting, and Fuel Cell System Integration Options

NASA Technical Reports Server (NTRS)

Vasquez, Arturo

2011-01-01

An advanced reactant pressure regulator with an internal ejector reactant circulation pump has been developed to support NASA's future fuel cell power systems needs. These needs include reliable and safe operation in variable-gravity environments, and for exploration activities with both manned and un manned vehicles. This product was developed for use in Proton Exchange Membrane Fuel Cell (PEMFC) power plant reactant circulation systems, but the design could also be applied to other fuel cell system types, (e.g., solid-oxide or alkaline) or for other gas pressure regulation and circulation needs. The regulator design includes porting for measurement of flow and pressure at key points in the system, and also includes several fuel cell system integration options. NASA has recognized ejectors as a viable alternative to mechanical pumps for use in spacecraft fuel cell power systems. The ejector motive force is provided by a variable, high-pressure supply gas that travels through the ejector s jet nozzle, whereby the pressure energy of the fluid stream is converted to kinetic energy in the gas jet. The ejector can produce circulation-to-consumption-flow ratios that are relatively high (2-3 times), and this phenomenon can potentially (with proper consideration of the remainder of the fuel cell system s design) be used to provide completely for reactant pre-humidification and product water removal in a fuel cell system. Specifically, a custom pressure regulator has been developed that includes: (1) an ejector reactant circulation pump (with interchangeable jet nozzles and mixer sections, gas-tight sliding and static seals in required locations, and internal fluid porting for pressure-sensing at the regulator's control elements) and (2) internal fluid porting to allow for flow rate and system pressure measurements. The fluid porting also allows for inclusion of purge, relief, and vacuum-breaker check valves on the regulator assembly. In addition, this regulator could also be used with NASA's advanced nonflow-through fuel cell power systems by simply incorporating a jet nozzle with an appropriate nozzle diameter.

Nonimaging light concentrator with uniform irradiance

DOEpatents

Winston, Roland; Gee, Randy C.

2003-04-01

A nonimaging light concentrator system including a primary collector of light, an optical mixer disposed near the focal zone for collecting light from the primary collector, the optical mixer having a transparent entrance aperture, an internally reflective housing for substantially total internal reflection of light, a transparent exit aperture and an array of photovoltaic cells disposed near the transparent exit aperture.

Design of an exhaust mixer nozzle for the Avco-Lycoming Quiet Clean General Aviation Turbofan (QCGAT)

NASA Technical Reports Server (NTRS)

Hurley, J. F.; Anson, L.; Wilson, C.

1978-01-01

This report describes the design configuration and method used to design the forced engine exhaust to bypass air mixing system for Lycoming's QCGAT engine. This mixer is an integral part of the total engine and nacelle system and was configured to reduce the propulsion system noise and fuel consumption levels.

29 CFR 570.62 - Occupations involved in the operation of bakery machines (Order 11).

Code of Federal Regulations, 2010 CFR

2010-07-01

... dough mixer; batter mixer; bread dividing, rounding, or molding machine; dough brake; dough sheeter... cookie or cracker machine. (b) Exceptions. (1) This section shall not apply to the operation, including... as prohibited by § 570.61(a)(4). (2) This section shall not apply to the operation of pizza-dough...

Digital-Difference Processing For Collision Avoidance.

NASA Technical Reports Server (NTRS)

Shores, Paul; Lichtenberg, Chris; Kobayashi, Herbert S.; Cunningham, Allen R.

1988-01-01

Digital system for automotive crash avoidance measures and displays difference in frequency between two sinusoidal input signals of slightly different frequencies. Designed for use with Doppler radars. Characterized as digital mixer coupled to frequency counter measuring difference frequency in mixer output. Technique determines target path mathematically. Used for tracking cars, missiles, bullets, baseballs, and other fast-moving objects.

77 FR 6560 - Notice of a Project Waiver of the Buy American Requirement of the American Recovery and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-08

... Section 1605 of ARRA. This action permits the purchase of the selected vertical linear motion mixers not...: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: The Regional Administrator of EPA Region 6 is... purchase of ten (10) vertical linear motion mixers for the Clean Water State Revolving Fund (CWSRF) Hornsby...

A Simple Experiment for Teaching Process Intensification by Static Mixing in Chemical Reaction Engineering

ERIC Educational Resources Information Center

Baz-Rodríguez, Sergio; Herrera-Soberanis, Natali; Rodríguez-Novelo, Miguel; Guillén-Francisc, Juana; Rocha-Uribe, José

2016-01-01

An experiment for teaching mixing intensification in reaction engineering is described. For this, a simple tubular reactor was constructed; helical static mixer elements were fabricated from stainless steel strips and inserted into the reactor. With and without the internals, the equipment operates as a static mixer reactor or a laminar flow…

INTERIOR VIEW, LOOKING WEST, WITH CRANE OPERATOR, TED SEALS, POURING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR VIEW, LOOKING WEST, WITH CRANE OPERATOR, TED SEALS, POURING MOLTEN METAL INTO A 1,300 TON ELECTRIC HOLDING FURNACE OR MIXER. AN ELECTRONIC SCALE RECORDED THAT 50.5 TONS OF METAL WERE POURED INTO THE FURNACE DURING THIS POUR. - American Cast Iron Pipe Company, Mixer Building, 1501 Thirty-first Avenue North, Birmingham, Jefferson County, AL

Influence of melt mixer on injection molding of thermoset elastomers

NASA Astrophysics Data System (ADS)

Rochman, Arif; Zahra, Keith

2016-10-01

One of the drawbacks in injection molding is that the plasticizing screw is short such that polymers having high concentrations of additives, such as thermoset elastomers, might not mix homogeneously within the short period of time during the plasticizing stage. In this study, various melt mixers inside the nozzle chamber, together forming a mixing nozzle, were developed. Three different materials were investigated, namely nitrile butadiene rubber (NBR), ethylene propylene-diene monomer (EPDM) and fluorocarbon (FKM). The use of these melt mixers resulted in better homogeneity and properties of the molded parts despite a curing time reduction of 10 s. This was due to the increase in mixing and shearing introduced a higher rate of crosslinking formation in the molded parts.

Source conductance scaling for high frequency superconducting quasiparticle receivers

NASA Technical Reports Server (NTRS)

Ke, Qing; Feldman, M. J.

1992-01-01

It has been suggested that the optimum source conductance G(sub s) for the superconductor-insulator-superconductor (SIS) quasiparticle mixer should have a l/f dependence. This would imply that the critical current density of SIS junctions used for mixing should increase as frequency squared, a stringent constraint on the design of submillimeter SIS mixers, rather than in simple proportion to frequency as previously believed. We have used Tucker's quantum theory of mixing for extensive numerical calculations to determine G(sub s) for an optimized SIS receiver. We find that G(sub s) is very roughly independent of frequency (except for the best junctions at low frequency), and discuss the implications of our results for the design of submillimeter SIS mixers.

Facile fabrication of a rigid and chemically resistant micromixer system from photocurable inorganic polymer by static liquid photolithography (SLP).

PubMed

Fang, Qingling; Kim, Dong-Pyo; Li, Xiaodong; Yoon, Tae-Ho; Li, Yihe

2011-08-21

Highly effective mixing in microchannels is important for most chemical reactions conducted in microfluidic chips. To obtain a rigid and chemically resistant micromixer system at low cost, we fabricated a Y-shaped microchannel with built-in mixer structures by static liquid photolithography (SLP) from methacrylated polyvinylsilazane (MPVSZ) as an inorganic polymer photoresist which was then converted to a silicate phase by hydrolysis in vaporized ammonia atmosphere at 80 °C. The microchannel incorporating herringbone mixer structures was bonded with a matching polydimethylsiloxane (PDMS) open channel which was pre-coated by perhydropolysilazane (PHPS)-based mixture, and finally treated by additional hydrolysis at room temperature to convert the PHPS layer to a silica phase. Finally, the chemical resistance of the microfluidic system with embedded micromixer was confirmed with various solvents, and the excellent mixing performance in a short mixing length of 2.3 cm was demonstrated by injecting two different colored fluids into the microchannel. This journal is © The Royal Society of Chemistry 2011

A 850 GHz SIS receiver employing silicon micro-machining technology

NASA Technical Reports Server (NTRS)

Kooi, J. W.; Pety, J.; Schaffer, P. L.; Phillips, T. G.; Bumble, B.; LeDuc, H. G.; Walker, C. K.

1996-01-01

A 850 GHz superconductor-insulator-superconductor (SIS) heterodyne receiver which uses a radiofrequency tuned niobium tunnel junction fabricated on a 1 micron thick silicon nitrate membrane, is reported. From video and heterodyne measurements, it was calculated that the niobium film loss in the radiofrequency matching network is about 6.8 dB at 822 GHz. These results are approximately a factor of two higher than the theoretical loss predicted by the Mattis-Bardeen theory in the extreme anomalous limit. The junction design and the receiver configuration are described, including the mixer block, the membrane construction and the cooled optics. The performance tests using a Fourier transform spectrometer to measure the response of the radiofrequency matching network, and the SIS simulations of the receiver response to cold and hot loads, the infrared noise contribution and the overall mixer conversion efficiency, are reported. It is concluded that the receiver response is limited by the absorption loss in the radiofrequency matching network.

Separation dynamics of dense dispersions in laminar pipe flows: An experimental and numerical study

NASA Astrophysics Data System (ADS)

Voulgaropoulos, Victor; Jamshidi, Rashid; Zainal Abidin, M. I. I.; Angeli, Panagiota

2017-11-01

The physical mechanisms governing the separation of dense liquid dispersed flows in pipes are not well understood. In this work, both experiments and numerical simulations are performed to investigate these mechanisms. Liquid-liquid dispersions are generated using a static mixer and their evolution is studied along a horizontal pipe (26mm ID) at laminar flow and input dispersed phase volume fractions up to 50%. To conduct optical measurements (PLIF and PIV) in the dense dispersions, the refractive index of both liquids is matched. Measurements are carried out at two axial locations downstream the mixer (15D and 135D, where D is the pipe diameter). Homogeneous dispersions, observed at 15D, segregate at 135D. The packing of the drops results in asymmetric velocity profiles and high slip velocities. The mixture approach is used in the numerical simulations, including gravity and shear-induced diffusion of drops. The predictions on separation and on velocity fields agree well with the experiments. Research funded by Chevron.

A single active nanoelectromechanical tuning fork front-end radio-frequency receiver

NASA Astrophysics Data System (ADS)

Bartsch, Sebastian T.; Rusu, A.; Ionescu, Adrian M.

2012-06-01

Nanoelectromechanical systems (NEMS) offer the potential to revolutionize fundamental methods employed for signal processing in today’s telecommunication systems, owing to their spectral purity and the prospect of integration with existing technology. In this work we present a novel, front-end receiver topology based on a single device silicon nanoelectromechanical mixer-filter. The operation is demonstrated by using the signal amplification in a field effect transistor (FET) merged into a tuning fork resonator. The combination of both a transistor and a mechanical element into a hybrid unit enables on-chip functionality and performance previously unachievable in silicon. Signal mixing, filtering and demodulation are experimentally demonstrated at very high frequencies ( > 100 MHz), maintaining a high quality factor of Q = 800 and stable operation at near ambient pressure (0.1 atm) and room temperature (T = 300 K). The results show that, ultimately miniaturized, silicon NEMS can be utilized to realize multi-band, single-chip receiver systems based on NEMS mixer-filter arrays with reduced system complexity and power consumption.

Performance of a vane driven-gear pump

NASA Technical Reports Server (NTRS)

Heald, R H

1921-01-01

Given here are the results of a test conducted in a wind tunnel on the performance of a vane-driven gear pump used to pump gasoline upward into a small tank located within the upper wing from which it flows by gravity to the engine carburetor. Information is given on the efficiency of the pump, the head resistance of the vanes, the performance and characteristics of the unit with and without housing about the vanes, the pump performance when motor driven, and resistance and power characteristics.

Blood warming, pump heating and haemolysis in low-flow extracorporeal life support; an in vitro study using freshly donated human blood.

PubMed

Kusters, R W J; Simons, A P; Lancé, M D; Ganushchak, Y M; Bekers, O; Weerwind, P W

2017-01-01

Low-flow extracorporeal life support can be used for cardiopulmonary support of paediatric and neonatal patients and is also emerging as a therapy for patients suffering from exacerbation of chronic obstructive pulmonary disease. However, pump heating and haemolysis have proven to negatively affect the system and outcome. This in vitro study aimed at gaining insight into blood warming, pump heating and haemolysis related to the performance of a new low-flow centrifugal pump. Pump performance in the 400-1,500 ml/min flow range was modulated using small-sized dual-lumen catheters and freshly donated human blood. Measurements included plasma free haemoglobin, blood temperature, pump speed, pump pressure, blood flow and thermographic imaging. Blood warming (ΔT max =0.5°C) had no relationship with pump performance or haemolysis (R 2 max =0.05). Pump performance-related parameters revealed no relevant relationships with haemolysis (R 2 max =0.36). Thermography showed no relevant heat zones in the pump (T max =36°C). Concerning blood warming, pump heating and haemolysis, we deem the centrifugal pump applicable for low-flow extracorporeal circulation.

The noncavitating performance and life of a small vane-type positive displacement pump in liquid hydrogen

NASA Technical Reports Server (NTRS)

Ulbricht, T. E.; Hemminger, J. A.

1986-01-01

The low flow rate and high head rise requirements of hydrogen/oxygen auxiliary propulsion systems make the application of centrifugal pumps difficult. Positive displacement pumps are well-suited for these flow conditions, but little is known about their performance and life characteristics in liquid hydrogen. An experimental and analytical investigation was conducted to determine the performance and life characteristics of a vane-type, positive displacement pump. In the experimental part of this effort, mass flow rate and shaft torque were determined as functions of shaft speed and pump pressure rise. Since liquid hydrogen offers little lubrication in a rubbing situation, pump life is an issue. During the life test, the pump was operated intermittently for 10 hr at the steady-state point of 0.074 lbm/sec (0.03 kg/sec) flow rate, 3000 psid (2.07 MPa) pressure rise, and 8000 rpm (838 rad/sec) shaft speed. Pump performance was monitored during the life test series and the results indicated no loss in performance. Material loss from the vanes was recorded and wear of the other components was documented. In the analytical part of this effort, a comprehensive pump performance analysis computer code, developed in-house, was used to predict pump performance. The results of the experimental investigation are presented and compared with the results of the analysis. Results of the life test are also presented.

Reductant injection and mixing system

DOEpatents

Reeves, Matt; Henry, Cary A.; Ruth, Michael J.

2016-02-16

A gaseous reductant injection and mixing system is described herein. The system includes an injector for injecting a gaseous reductant into an exhaust gas stream, and a mixer attached to a surface of the injector. The injector includes a plurality of apertures through which the gaseous reductant is injected into an exhaust gas stream. The mixer includes a plurality of fluid deflecting elements.

Pesticide Safety for Non-Certified Mixers, Loaders and Applicators = Uso Seguro de Pesticidas para Mezcladores, Cargadores y Aplicadores no Certificados.

ERIC Educational Resources Information Center

Poli, Bonnie; Fluker, Sam S.

Written in English and Spanish and completely illustrated, this manual provides basic safety information for pesticide workers. Mixers, loaders, and applicators work with pesticides at their greatest strength and have the highest risk of poisoning. Understanding the pesticide label is the first step to pesticide safety. The words…

A Handheld LED Coloured-Light Mixer for Students to Learn Collaboratively the Primary Colours of Light

ERIC Educational Resources Information Center

Nopparatjamjomras, Suchai; Chitaree, Ratchapak; Panijpan, Bhinyo

2009-01-01

To overcome students' inaccurate prior knowledge on primary additive colours, a coloured-light mixer has been constructed to enable students to observe directly the colours produced and reach the conclusion by themselves that the three primary colours of light are red, green, and blue (NOT red, yellow, and blue). Three closely packed tiny…