1.5-V square-root domain first-order filter with multiple operating points

Tip clearance has a great effect on the flow and pressure fluctuation characteristics in a multiphase pump, especially at multiple operating points. The phase distribution and pressure fluctuation in tip clearance in a multiphase pump are revealed using the CFD (computational fluid dynamics) technology and high-speed photography methods. In this paper, the phase distribution, the gas-liquid two-phase velocity slip, and the pressure fluctuation intensity are comprehensively analyzed. Results show with the increase of the tip clearance, the multiphase pump pressurization performance is obviously deteriorated. In the meantime, the gas accumulation mainly occurs at the hub, the blade suction side (SS), and the tip clearance, and the maximum gas-liquid two-phase velocity difference is near the impeller streamwise of 0.4. In addition, the tip clearance improves the gas-liquid two-phase distribution in the pump, that is, the larger the tip clearance is, the more uniform the gas-liquid distribution becomes. Furthermore, the gas leads to the maximum pressure fluctuation intensity in the tip clearance which is closer to the tip leakage flow (TLF) outlet, and has a greater effect on the degree of flow separation in the tip clearance.

Download Full-text

New Mathematical Modeling Approach for Predicting Microbial Inactivation by High Hydrostatic Pressure

Applied and Environmental Microbiology ◽

10.1128/aem.02211-06 ◽

2007 ◽

Vol 73 (8) ◽

pp. 2468-2478 ◽

Cited By ~ 35

Author(s):

Bernadette Klotz ◽

D. Leo Pyle ◽

Bernard M. Mackey

Keyword(s):

Microbial Inactivation ◽

Inactivation Kinetics ◽

Published Data ◽

Model Parameters ◽

Order Kinetic ◽

Square Root ◽

Additional Time ◽

Decimal Reduction Time ◽

First Order ◽

Primary Model

ABSTRACT A new primary model based on a thermodynamically consistent first-order kinetic approach was constructed to describe non-log-linear inactivation kinetics of pressure-treated bacteria. The model assumes a first-order process in which the specific inactivation rate changes inversely with the square root of time. The model gave reasonable fits to experimental data over six to seven orders of magnitude. It was also tested on 138 published data sets and provided good fits in about 70% of cases in which the shape of the curve followed the typical convex upward form. In the remainder of published examples, curves contained additional shoulder regions or extended tail regions. Curves with shoulders could be accommodated by including an additional time delay parameter and curves with tails shoulders could be accommodated by omitting points in the tail beyond the point at which survival levels remained more or less constant. The model parameters varied regularly with pressure, which may reflect a genuine mechanistic basis for the model. This property also allowed the calculation of (a) parameters analogous to the decimal reduction time D and z, the temperature increase needed to change the D value by a factor of 10, in thermal processing, and hence the processing conditions needed to attain a desired level of inactivation; and (b) the apparent thermodynamic volumes of activation associated with the lethal events. The hypothesis that inactivation rates changed as a function of the square root of time would be consistent with a diffusion-limited process.

Download Full-text

Direct Action of Light in Naturally Pigmented Muscle Fibers

The Journal of General Physiology ◽

10.1085/jgp.46.2.333 ◽

1962 ◽

Vol 46 (2) ◽

pp. 333-342 ◽

Cited By ~ 24

Author(s):

Howard H. Seliger

Keyword(s):

Visual Pigment ◽

Absorption Maximum ◽

Pupil Diameter ◽

Direct Action ◽

Pigment Epithelium ◽

Action Spectrum ◽

Square Root ◽

Light Reaction ◽

First Order ◽

Iris Sphincter

Contraction due to light in excised eel irises appears to follow a simple first order law. The action spectrum for contraction has a maximum which agrees with the eel rhodopsin absorption maximum. Inasmuch as rhodopsin is the rod pigment-opsin complex and the iris sphincter pupillae evolves from the pigment epithelium of the retina in the region of the iris, the muscle pigment might be the same as the visual pigment. In the human eye the contraction of the iris sphincter is activated only by light incident on the retina and the pupil diameter varies inversely with the square root of the light intensity. The inverse first power relation observed in the present experiments suggests a more primitive origin for the light reaction in eel irises. Relaxation is a much slower process and can be approximated as the sum of two first order processes.

Download Full-text

Design of STATCOM damping control with multiple operating points: a multimodel LMI approach

IEE Proceedings - Generation Transmission and Distribution ◽

10.1049/ip-gtd:20050417 ◽

2006 ◽

Vol 153 (4) ◽

pp. 375 ◽

Cited By ~ 20

Author(s):

C.-F. Xue ◽

X.-P. Zhang ◽

K.R. Godfrey

Keyword(s):

Lmi Approach ◽

Damping Control ◽

Operating Points ◽

Multiple Operating Points

Download Full-text

Application of NMI to the Design of FACTS Damping Control with Multiple Operating Points

2007 IEEE International Conference on System of Systems Engineering ◽

10.1109/sysose.2007.4304310 ◽

2007 ◽

Cited By ~ 1

Author(s):

X.-P. Zhang ◽

C.-F. Xue ◽

K. R. Godfrey

Keyword(s):

Damping Control ◽

Operating Points ◽

Multiple Operating Points

Download Full-text

Improved Electronically-Tunable Current-Mode Square-Root-Domain First-Order Multifunction Filter

Journal of Circuits System and Computers ◽

10.1142/s0218126621501905 ◽

2021 ◽

pp. 2150190

Author(s):

Manoj Kumar Jain

Keyword(s):

Transient Response ◽

Current Mode ◽

Square Root ◽

Spice Simulation ◽

First Order ◽

Low Pass ◽

Multifunction Filter ◽

Simulation Results ◽

Electronically Tunable ◽

High Pass

Some time back, Kircay reported an electronically-tunable current-mode square-root-domain first-order filter capable of realizing low-pass (LP), high-pass (HP) and all-pass (AP) filter functions. When simulated in SPICE, Kircay’s circuit has been found to exhibit DC offsets in case of LP and AP responses and incorrect transient response in case of HP response. In this paper, an improved circuit overcoming these difficulties/deficiencies has been suggested and its workability of the improved circuit as well as its capability in meeting the intended objectives has been demonstrated by SPICE simulation results.

Download Full-text