Bubble kinematics in a sheared foam

We characterize the kinematics of bubbles in a sheared two-dimensional foam using statistical measures. We consider the distributions of both bubble velocities and displacements. The results are discussed in the context of the expected behavior for a thermal system and simulations of the bubble model. There is general agreement between the experiments and the simulation, but notable differences in the velocity distributions point to interesting elements of the sheared foam not captured by prevalent models

Linear differential pressure sensor Patent

Design and development of pressure sensor for measuring differential pressures of few pounds per square inc

Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture

Integrated multi-trophic aquaculture pays more attention as a bio-integrated food production system that serves as a model of sustainable aquaculture, minimizes waste discharge, increases diversity and yields multiple products. The objectives of this research were to analyze the efficiency of total ammonia nitrogen biofiltration and its effect on carrying capacity of fish rearing units. Pilot-scale bioreactor was designed with eight run-raceways (two meters of each) that assembled in series. Race 1-3 were used to stock silky worm (Tubifex sp) as detrivorous converter, then race 4-8 were used to plant three species of leaf-vegetable as photoautotrophic converters, i.e; spinach (Ipomoea reptana), green mustard (Brassica juncea) and basil (Ocimum basilicum). The three plants were placed in randomized block design based on water flow direction. Mass balance of nutrient analysis, was applied to figure out the efficiency of bio-filtration and its effect on carrying capacity of rearing units. The result of the experiment showed that 86.5 % of total ammonia nitrogen removal was achieved in 32 days of culturing period. This efficiency able to support the carrying capacity of the fish tank up to 25.95 kg/lpm with maximum density was 62.69 kg/m3 of fish biomass productio

Some Observations of Flow Patterns and Statistical Properties of Three Component Flows

Vertical air-water flows, solids-water flows and three component air-solids-water flows were investigated in a Three Component Flow Facility. Visual observations of the flow patterns show that three component flows undergo transition and can exhibit strong unsteady vortical motions. Measurements of the fluctuations in cross-sectionally averaged volume fraction measurements were made. The statistical properties of the fluctuations are presented in terms of their amplitude and coherent time scale in the form of the Signal To Noise Ratio (STNR) and the Time Constant (symbol), respectively. Remarkably, the solids-water flows and the dispersed bubbly air-water flows exhibit almost identical values of STNR for the same volume fraction. Equally remarkable in the linear relationship between the Time Constant and the mean bubble or particle velocity; this relationship is found to have the same constant of proportionality for both species in the well behaved disperse regime. In the two-component churn-turbulent and the three-component agitated vortical regimes, the variables (symbol) and STNR significantly deviate from their dispersed regime values. The onset of large coherent structures characteristic of these regimes is reflected by a rise in the amplitude of the fluctuations and a marked increase in their coherent time scale. The results of this study demonstrate the large information content in the fluctuations of the measured quantity, both as a flow regime indicator and as a measure of flow quantities in two- and three-component flows

Sophisticated software systems for small self-contained space shuttle payload G285

The increasing development of small microprocessor systems has allowed the use of more advanced software in the area of control systems. This paper discusses the development of software for small Space Shuttle Getaway Special Project payloads using payload G285 as a case example. The development process behind a space related software package (as in any software package) is a major factor. The design process for G285 is discussed in some detail along with the general scheme behind data acquisition and thermal environmental control for a space related payload. Additionally, key concepts in a software system concern the implementation of redundant systems, error detection, and error response. All of these factors are discussed

Impact of Bioparticle Recirculation in a Circulating Fluidized Bed Biofilm Reactor on Simultaneous Organic and Nitrogen Removal

The Circulating Fluidized Bed Biofilm Reactor (CFBBR), a bioparticle technology designed for biological nutrient removal, has been implemented to achieve considerable biodegradation efficiency and low sludge production, compared with activated sludge system and typical biofilm technology. The inherent advantages of bioparticle technology are enhanced substantially by the CFBBR, for example, decoupling of hydraulic retention time (HRT) from solids retention time (SRT), large specific surface area, ideal conditions for biofilm ecosystem. In this work, bioparticle recirculation, as a novel control method for bioparticle system, was demonstrated in CFBBRs. To verify the impact of bioparticle recirculation on the reactor performance, bio-kinetics and hydrodynamic behavior, three lab-scale CFBBRs were developed and tested for carbon and nitrogen removal from synthetic wastewater as well as municipal wastewater. During all extended experiments, bioparticles are slowly transferred from the Riser (Anoxic column) to the Downer (Aerobic column) for specific bio-reactions, and then recirculating back to the Riser for refreshment. A low shear stress was maintained in order to achieve rich biofilm conditions, where the predation process was encouraged. Furthermore, a novel one-dimensional (1D) bioparticle model successfully combined hydrodynamic parameters with biofilm kinetics to simulate dynamic surface area and dynamic shear stress in bioparticle process. Two lab-scale CFBBRs fed with synthetic wastewater were applied for extended experimental tests and pseudo-steady-state study of bioparticle recirculation. Over the 285 days of synthetic wastewater experiments in a lab-scale (4 L) CFBBR, over 95% COD removal and 85% TN removal were achieved during slow bioparticle circulation between Riser (Anoxic) and Downer (Aerobic). Furthermore, with sodium acetate as the carbon source, an extremely low net sludge yield of 0.034 mgVSS/mgCOD was observed concomitant with the appearance of macro-consumers and aquatic worms. Another extended (200 days) experiment of a lab-scale (8.5 L) CFBBR demonstrated the feasibility of the pseudo-steady-state for integrated COD, nitrogen removal and worm predation, and the results proved that the worm predation has a significant impact on the pseudo-steady-state performance of the CFBBR, decreasing biomass yield and oxygen concentration while increasing expanded bed height. Subsequently, Bioparticle Enrichment-Predation circulation (BEP circulation), comprised enrichment (in Riser Bottom section), transportation (in Riser Top section), predator-cultivation (in Downer Top), and deactivation (in Downer Bottom), was proposed as a novel bioparticle recirculation pattern, which effectively improves performance and enhances stability of CFBBR. The bioparticle process involving worm predation proved to be achievable through a self-balancing worm bioparticle process and BEP circulation, and a self-balancing micro-community along with BEP circulation would provide an effective control of the bioparticle system integrated COD and nitrogen removal as well as strong predation. A CFBBR model was established based on 1D-bioparticle model to investigate hydrodynamic conditions of CFBBR. The model integrated the anoxic riser and aerobic downer, and bioparticle circulation was simulated as a function of expanded bed growth. Experimental data from a 6-L CFBBR fed with municipal wastewater was used to validate the simulation. The CFBBR model can be used to quantify the bed voidage in the riser, and expanded bed height and bed voidage in the downer to achieve good biodegradation performance, optimize the up-flow velocity in both the riser and the downer, then calculate the amount of media for the system. The impact of bioparticle circulation rate (vs) was also studied in the lab, verifyied by three different vs i.e. 50 g bare particle/d, 100 g bare particle/d and 200 g bare particle/d. The range of operational bioparticle circulation rate was calculated by 1D-bioparticle model, which provides crucial control parameter for the CFBBR