Method to Improve the Linearity of Active Commutating Mixers Using Dynamic Current Injection

A double balanced (DBM) CMOS mixer providing high linearity is presented in this paper. A cross-coupled pair used in the IF stage of the mixer to dynamically inject current into the to mixer provide a high linearity. The proposed DBM was fabricated using a standard 130-nm CMOS process and was tested on-wafer. The double balanced mixer delivers 10 dB conversion gain, 9.5 dBm IIP3, and input P1dB of -2.4 dBm. RF bandwidth of the proposed mixer is 6 GHz, covering 0.5 GHz to 6.5 GHz with IF bandwidth of 300 MHz. RF to IF and LO to IF isolation are also better than 59 dB in the whole frequency band. The circuit uses an area of 0.015 mm2 excluding bonding pads and draw 4.5mW from a 1.2V supply.

Method to Improve the Conversion Gain Flatness of Transformer-Coupled Mixers

A 4-10 GHz, on-chip balun based current commutating mixer is proposed. Tunable resistive feedback is used at the transconductance stage for wideband response, and interlaced stacked transformer is adopted for good balance of the balun. Measurement results show that a conversion gain of 13.5 dB, an IIP3 of 4 dBm and a noise figure of 14 dB are achieved with 5.6 mW power consumption under 1.2 V supply. The simulated amplitude and phase imbalance is within 0.9 dB and ±2◦ over the band.

Scale-up of mixer granulators for effective liquid distribution

There is considerable anecdotal evidence from industry that poor wetting and liquid distribution can lead to broad granule size distributions in mixer granulators. Current scale-up scenarios lead to poor liquid distribution and a wider product size distribution. There are two issues to consider when scaling up: the size and nature of the spray zone and the powder flow patterns as a function of granulator scale. Short, nucleation-only experiments in a 25L PMA Fielder mixer using lactose powder with water and HPC solutions demonstrated the existence of different nucleation regimes depending on the spray flux Psi(a)-from drop-controlled nucleation to caking. In the drop-controlled regime at low Psi(a) values. each drop forms a single nucleus and the nuclei distribution is controlled by the spray droplet size distribution. As Psi(a) increases, the distribution broadens rapidly as the droplets overlap and coalesce in the spray zone. The results are in excellent agreement with previous experiments and confirm that for drop-controlled nucleation. Psi(a) should be less than 0.1. Granulator flow studies showed that there are two powder flow regimes-bumping and roping. The powder flow goes through a transition from bumping to roping as impeller speed is increased. The roping regime gives good bed turn over and stable flow patterns. This regime is recommended for good liquid distribution and nucleation. Powder surface velocities as a function of impeller speed were measured using high-speed video equipment and MetaMorph image analysis software, Powder surface velocities were 0.2 to 1 ms(-1)-an order of magnitude lower than the impeller tip speed. Assuming geometrically similar granulators, impeller speed should be set to maintain constant Froude number during scale-up rather than constant tip speed to ensure operation in the roping regime. (C) 2002 Published by Elsevier Science B.V.

Continuous Counter-current Solvent Extraction of Magnesium and Calcium from Lithium-rich Brine

Solvent extraction of calcium and magnesium impurities from a lithium-rich brine (Ca ~ 2,000 ppm, Mg ~ 50 ppm, Li ~ 30,000 ppm) was investigated using a continuous counter-current solvent extraction mixer-settler set-up. The literature review includes a general review about resources, demands and production methods of Li followed by basics of solvent extraction. Experimental section includes batch experiments for investigation of pH isotherms of three extractants; D2EHPA, Versatic 10 and LIX 984 with concentrations of 0.52, 0.53 and 0.50 M in kerosene respectively. Based on pH isotherms LIX 984 showed no affinity for solvent extraction of Mg and Ca at pH ≤ 8 while D2EHPA and Versatic 10 were effective in extraction of Ca and Mg. Based on constructed pH isotherms, loading isotherms of D2EHPA (at pH 3.5 and 3.9) and Versatic 10 (at pH 7 and 8) were further investigated. Furthermore based on McCabe-Thiele method, two extraction stages and one stripping stage (using HCl acid with concentration of 2 M for Versatic 10 and 3 M for D2EHPA) was practiced in continuous runs. Merits of Versatic 10 in comparison to D2EHPA are higher selectivity for Ca and Mg, faster phase disengagement, no detrimental change in viscosity due to shear amount of metal extraction and lower acidity in stripping. On the other hand D2EHPA has less aqueous solubility and is capable of removing Mg and Ca simultaneously even at higher Ca loading (A/O in continuous runs > 1). In general, shorter residence time (~ 2 min), lower temperature (~23 °C), lower pH values (6.5-7.0 for Versatic 10 and 3.5-3.7 for D2EHPA) and a moderately low A/O value (< 1:1) would cause removal of 100% of Ca and nearly 100% of Mg while keeping Li loss less than 4%, much lower than the conventional precipitation in which 20% of Li is lost.

Organizational maintenance manual : drier-mixer, bituminous-concrete materials, wheel mounted, gasoline engine driven, 2 wheels, pneumatic tires, 3 to 10 ton per hr (Wylie model PM-415-MIL), FSN 3895-755-4761.

"April 1966."

Organizational maintenance repair parts and special tools lists : mixer, rotary tiller, diesel engine driven, 4 wheel, pneumatic tires, self-propelled, with flat hook tines (Rex Chainbelt, Inc. model HDTM), FSN 3895-987-5536).

"10 February 1970"--Change no. 1.

Operator's manual [microform] : truck tractor, line haul, 50,000 GVWR, 6 x 4, M915 (NSN 2320-01-028-4396), truck tractor, light equipment transporter (let), 56,000 CVWR, 6 x 6, w/winch, M916 (NSN 2320-01-028-4396), truck tractor, medium equipment transporter (met), 75,000 GVWR, 8 x 6, w/winch, M920 (NSN 2320-01-028-4397) : truck chassis, 75,000 BVWR, 8 x 6 for 20 ton dump truck, M917 (NSN 3806-01-028-4389), truck chassis, 56,000 GVWR, 6 x 8, for bituminous distributor truck, M918 (NSN 3805-01-028-4390), truck chassis, 75,000 GVWR, 8 x 6, for concrete mobile mixer truck, M819 (NSN 3856-01-4391).

"May 1980."

Operator, organizational, field, and depot maintenance manual : mixer, concrete, trailer mounted, gasoline driven, 16 cu ft (Chain Belt model HBG), FSN 3895-835-4512.

Includes index.

Operator's, manual : mixer, concrete, trailer mounted: gasoline driven: 16 cu ft (construction machinery model 16 SM), FSN 3895-807-7985.

"June 1963."

Technical manual, direct and general support maintenance manual : mixer, concrete, 4 wheel trailer mounted, gasoline engine driven, non tilt, 16 cu. ft., (T.L. Smith Company model 499A), FSN 3895-444-1531.

Includes index.

Operator, organizational, direct support, general support, and depot maintenance manual : drier-mixer, bituminous-concrete material, wheel mounted, GED, 2 wheel, pneumatic tires, 3 to 10 ton per hr, McConnaughay model HTD-A-67, FSN 3895-832-6230.

Includes index.

Technical manual, operator and organizational maintenance manual : mixer, concrete, 4 wheel trailer mounted, gasoline engine driven, non tilt, 16 cu. ft. (T.L. Smith Company model 499A), FSN 3895-444-1531.

"January 1972."

Operator, organizational, direct support, general support, and depot maintenance manual : mixer, bituminous material, non-self-loading, diesel engine driven (Barber-Greene model KA-60) FSN 3895-933-0577 with elevator, bucket type ... components of mixing plant, asphalt ....

"April 1968."

Operation instructions : concrete - mobile mixer body, M919, model 8CM-24/F, NSN 3895-01-028-4391 : Daffin Mobile Products Division of Barber-Greene Company.

"DAAE07-77-C-4211."

Direct support and general support maintenance : concrete-mobile mixer body, M919, model 8CM-24/F, NSN 3895-01-028-4391.

"September 1980."