Protein separation using a chitin monolith with a continuous flow system

This work was designed with two primary objectives. One is to test the hypothesis that initial microbial density has a significant effect on disinfection in a continuous flow system. The other is to validate the disinfection kinetics obtained from the batch studies in a continuous flow system. Four series of disinfection experiments were conducted at 15°C in phosphate buffer solution using a lab-scale continuously stirred tank reactor (CSTR). These experiments included the inactivation of E. coli in stationary phase using monochloramine (pH 7), the inactivation of E. coli in exponential phase using monochloramine (pH 7), the inactivation of B. subtilis vegetative cells in exponential phase using monochloramine (pH 7), and the inactivation of B. subtilis spores using ozone (pH 8). Prior to these experiments, the reactor was characterized as an ideal CSTR by performing step-input tracer tests. Statistical analyses of the CSTR disinfection data indicated that the initial microbial density had a significant effect on the inactivation of E. coli in stationary phase using monochloramine in the CSTR system. This result was consistent with the conclusion drawn from batch disinfection data analysis in a previous study. Effects of initial microbial density on disinfection efficiency were not observed in the other three series of experiments, suggesting that this effect might be specific to certain microorganisms in certain growth phases. The disinfection efficiency in a CSTR was predicted from the mathematical expression obtained from batch inactivation kinetics and the CSTR hydraulic characteristics. The predicted survival ratio was compared with the observed CSTR survival ratio in natural log units. For E. coli in both stationary phase and exponential phase, no significant difference existed between the two sets of data after system correction of the change of E. coli density in the tubing system, indicating that this approach could be used to predict the behavior of E. coli using monochloramine in continuous flow system from batch kinetics. For B. subtilis cells and spores, systematic differences between continuous flow and batch systems precluded the use of batch data for CSTR inactivation estimation.

This study compared the continuous positive airways pressure mode of the demand valve system of the Engstrom Erica ventilator with a custom-made continuous flow continuous positive airways pressure system in terms of the oxygen cost of breathing during weaning from mechanical ventilation. Ten consecutive patients in our intensive care unit, with thermodilution pulmonary artery flotation catheters in situ, were studied. Measurements were carried out under steady-state conditions, initially when breathing spontaneously with continuous positive airways pressure via the Erica and then when transition to the continuous flow system was achieved. There were no significant differences between the two methods of providing continuous positive airways pressure in terms of the measured and derived physiological variables studied, with the exception of oxygen consumption. Oxygen consumption with the continuous flow system was significantly less than with the Erica (142.8 (SEM 31.4) ml.min-1.m-2 compared with 165.8 (SEM 30.5) ml.min-1.m-2, p < 0.05). This difference reflects the reduced oxygen cost of breathing when the custom-made continuous flow system was used during weaning.

Removal of nitrate in semi and fully continuous-flow Donnan dialysis systems

In this retrospective study, we compared two systems, continuous flow (CF) (COBE Spectra) versus intermittent flow (IF) (Haemonetics V-50, M-30), in performance of therapeutic plateletapheresis (TP: N = 49 each) and therapeutic leukapheresis (TL: N = 29 each). Pre- and post-procedure cell reductions, specificity of removal, volumes removed, and incidence of adverse reactions were compared. Standard procedures with minor modifications, starch with IF only, and 180 minutes blood processing time were used. The CF system had a significantly lower percent reduction of platelets during TP at 43 +/- 17% than IF at 53 +/- 19%. However, no significant difference was found between CF and IF in percent reduction of white blood cells during TL with 49 +/- 16% and 42 +/- 14%, respectively. The CF system had significantly less hemoglobin reduction (5 +/- 4% vs. 19 +/- 9%, respectively) and white blood cell reduction (13 +/- 15% vs. 27 +/- 17%, respectively) for TP than IF and lower (not significant) hemoglobin reduction (9 +/- 8% vs. 12.4 +/- 8.2%, respectively) as well as platelet reduction (27 +/- 18% vs. 35 +/- 19%, respectively) for TL. CF also had significantly less volume removed than IF during TP (559 +/- 97 vs. 883 +/- 304, respectively) and TL (710 +/- 134 vs. 1405 +/- 421 ml, respectively). Incidence of reactions was lower for CF than IF during TP (8% vs. 10%, respectively) and during TL (14% vs. 21%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Heavy metal pollution has become a serious problem for living organisms. In this study, silk fibroin (SF)/ nylon-6 nanofiber matrices were formed by electrospinning and their surface was modified with calcium phosphate (CaP) crystals to increase the affinity of divalent heavy metals. The properties of matrices were evaluated as a filter matrix for copper adsorption from aqueous solution. Atten- uated total reflectance fourier transform infrared spectros- copy (ATR-FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXS), X-ray pho- toelectron spectroscopy (XPS), and alizarin red staining method were used for characterization. Adsorption studies were performed by batch and continuous system. The various parameters regarding adsorption process such as pH of solution, surface area, initial copper concentration, and flow rate were optimized. Toxicity values were assessed before and after the Cu(II) adsorption studies. The resultant SF/nylon-6 nanofiber matrices indicate an excellent fibrous structure without beads (fiber diameter at 250 ± 50 nm) and modified successfully with CaP crystals. Adsorption results showed that the removal efficiency of copper could reach 32 % by continuous flow system whereas 77 % by batch system. Acute toxicity bioassays using Vibrio fischeri showed that the toxicity decreased after continuous and batch flow systems. For desorption study, different concen- trations of various desorption solutions were used and the percentage of Cu(II) desorption was determined as 11 %, approximately.

Continuous flow systems have not been widely used in the study of benthic-pelagic coupling in marine systems. T h ~ s paper discusses the theoret~cal and practical use of continuous flow systems for the study of benthlc exchange processes and presents the results of experiments w h ~ c h compared continuous flow (open) and closed (batch) systems and investigated the sensitivity of exchange rates to residence t ~ m e s in a continuous flow system. Continuous flow systems minimize the problem of environmental dependency of benthic-pelagic exchange rates by maintaining initial experimental conditions throughout an ~ncubatlon. However, the selection of a supply rate (i .e. residence timc) is cntical in their operation. Variable res~dence times delineate 3 patterns of sediment-water exchange a hnear response which reflects an optimal supply rate, a feedback response which indicates deviation from initial experimental conditions (environmental dependency), and a washout response which results in an erroneous estimate of exchange. For either closed (batch) or continuous flow incubations, only linear responses result In valid estimates of sediment-water column exchange. Sediment oxygen consumption and benthic fluxes of NH,. NO,, PO, (1 station), and Si(OH), (both stations) were significantly greater when measured using continuous flow methodology than when using closed (batch) incubations. Sediment oxygen consumption as well a s fluxes of NO,+NO, varied directly with supply rdte, while fluxes of NH, were not significantly different over the range of supply rates tested. Examinations of overlying water nutrient concentrat~ons ~ndicated that observed differences in benthic fluxes between the 2 methods and the varying sensitivities of nutrient flux to supply rate were a function of the res~dence time of the overlying water In the core. Rates were s ~ m ~ l a r when both techniques resulted In linear rpsponses. Differences between techniques resulted when either feedback or washout responses were observed. The observed variable response among nutnents Indicated that the kinetics of ben th~c regeneration dlffer among nutrients and implies that operation of continuous flow systems (1.e. restdence time) should be opt~mized for the analyte under study. Open (continuous flow) systcms have many advantages for the determination of benthic-pelagic exchange rates. In a continuous flow system, initial experimental conditions are maintained throughout an incubation. This permits experiments of relatively long duration which allows ~ncreased statistical rigor and permits the direct study of causeeffect relationships through the use of experimental manipulations. The primary disadvantage of continuous flow systems lies in their labor-~ntensive operation.

A Comparison of the Growth of Daphnia Fed Continuously and at Regular Intervals

ABSTRACTThermal inactivation kinetics were evaluated in batch and continuous flow systems using phosphate buffer between 99 and 107°C for Bacillus cereus T and 128.5 and 139°C for Bacillus stearothermoohilus ATCC 12980 spores. zD‐Values for B. cereus spores in batch aid continuous flow systems were not significantly different; the continuous flow system was more lethal than the batch system. zD‐Values obtained using B. stearothermophilus spores in batch and continuous flow systems were different; the batch system was more lethal than the continuous flow system. Thus, use of batch generated data to predict or design continuous flow processes may not be accurate.

In Chapter 7 we introduced continuous flow systems having time-independent and place-dependent properties and, as a consequence, zero accumulation terms and continuous transport and production rates in their describing BE’s. There we focused on continuous plug flow systems as a subclass. In this chapter we turn to continuous mixed flow systems as a second subclass.

Continuous circulation of drilling fluid offers many benefits, including increased control of downhole pressure in relation to pore and fracture pressures along with enhanced wellbore cleaning. Although the concept of continuous circulation has been known to the industry for a long time, it has gained significance in recent years with real-time downhole pressure monitoring and control. Continuous circulation provides an uninterrupted data stream from downhole sensors and surface equipment even while making a connection, thereby never losing downhole pressure. Weatherford has developed a continuous flow system (CFS), including subs that crown the top of a drillpipe stand and an automated control system that switches mud flow between the top drive and the side flow port. During conventional drilling operations, CFS subs are passive drillstring components. When a new stand needs to be added, a CFS sub connected to a stand already drilled into the well is positioned in the rotary table, and a clamp carrying a side flowline is attached to it. Once the clamp has been securely attached, rig hands can move off the rig floor and conduct the rest of the operation from a remote control panel. At this point, the CFS sub works like a three-way valve. When a sleeve inside the CFS sub is pushed upward, it opens a side flow port on the sub and simultaneously closes an internal valve to cut off flow from the top drive. With concurrent operation of mud valves on a manifold skid, mud flow is redirected from the top drive to the side flow port before breaking the top-drive connection. Mud flow is also directed back to the top drive after adding a stand. The CFS can be used during trip-in and trip-out operations in an almost identical manner. Significant advantages of the CFS are easy implementation into the rig flow loop, automated switching of flow from the standpipe to the side entry port and back from a remote location, high consideration for personnel safety, limited impact on connection time, and a small footprint on the rig floor.

Biofloc technology (BFT) systems heavily rely on microbiota to mitigate ammonia toxicity and manage essential nutrient cycling. Understanding the diversity and functional role of microbiota within BFT-applied aquaculture systems is crucial for ensuring sustainable operations. Though some studies exist on BFT microbiota, research on microbial differences in Japanese eel aquaculture is still limited, hindering the wider application of BFT systems. In this study, we analyzed the characteristics of water quality factors and microbiota in Japanese eel (Anguilla japonica) breeding water, applying the BFT system. Using a metabarcoding approach, the diversity and community structure of aquatic microbiota were compared between BFT and continuous flow (CF) systems. The pH was significantly higher in CF water, while total ammonia nitrogen (TAN) and nitrite (NO2−-N) was higher in BFT water. Alpha diversity was significantly higher in BFT compared to CF systems, and it was correlated significantly with pH and TAN. In both BFT and CF water, the phyla Proteobacteria and Bacteroidota were found to be the most abundant. In the BFT water, a diverse array of bacterial taxa, including BFT-specific clades, were consistently present, while the microbiota in CF water was more variable and contained fewer specific taxa. In addition, bacterial functions related to nitrate reduction, sulfur compound oxidation, and chitinolysis were significantly more abundant in BFT than in CF systems. These findings highlight differences in water quality and microbiota between aquaculture systems, which can inform future research on the use of BFT for sustainable fish farming.

Continuous circulation of drilling fluid offers many benefits including increased control of downhole pressure in relation to pore and fracture pressures along with enhanced wellbore cleaning. While the concept of continuous circulation has been known for a long time, it has not been until recently that development of reliable systems have begun turning up. Continuous circulation provides an uninterrupted stream of data from sensors mounted downhole and on surface equipment even while making a connection, thereby never interrupting equivalent circulating density. Weatherford has developed a sub based continuous flow system (CFS) with an automated control system for switching mud flow between the top drive and side flow port. During conventional drilling operations, CFS subs are passive drill string components. When a new stand needs to be added, a CFS sub connected to the stand already drilled into the well is positioned in the rotary table and a clamp carrying a side flow line is attached to it. Once the clamp has been securely attached, rig hands can move off the rig floor with the rest of the operation taking place from a remote control panel. At this point CFS sub works like a three-way valve. When a sleeve inside CFS sub is pushed upward, it opens a side flow port on the sub simultaneously closing an internal valve to cut off flow from top drive. With concurrent operation of mud valves on a manifold skid, mud flow is redirected from the top drive to side flow port before breaking the top drive connection and back to the top drive after a new stand has been connected. Continuous flow system can be used during trip-in and trip-out operations in an almost identical manner. Significant strides have been made to introduce a new system with input from customers and exhaustive testing. The process of developing a new product can be long and tedious. It is important to lay out a road map to success not only with a thorough testing program but to make sure that once it has been tested the product is suitable to be utilized for field trials.

Determination of Cu(II) in environmental water samples using polymer inclusion membrane-TAC optode in a continuous flow system

Evaluation of fibre optical chemical sensors for flow analysis systems

The effects of ultrasonication of corn slurry, on particle size distribution and enzymatic hydrolysis was studied for the dry-grind mill ethanol industry. Two independent ultrasonic experiments were conducted at a frequency of 20 kHz; in batch and continuous systems. The ground corn slurry (33% m/v) was pumped at flow rates 10-28 L/min in continuous flow experiments, and sonicated at constant amplitude (20µmpeak-to-peak(p-p)). Ultrasonic batch experiments were conducted at varying amplitudes of 192-320µmp-p. After ultrasonication, StargenTM001 enzyme was added to the samples and a short 3h hydrolysis followed. The treated samples were found to yield 2-3 times more reducing sugar compared to the control (untreated) samples. In terms of energy density, the batch ultrasonic system was found to deliver 25-times more energy than the continuous flow systems. Although the experiments conducted in continuous system released less reducing sugar than the batch system, the continuous system was more energy efficient. The particle size of the sonicated corn slurry (both batch and continuous) was reduced relative to the controls (without treatment). The reduction of particle size was directly proportional to the energy input during sonication. The study suggests that both batch and continuous flow ultrasonic systems enhances enzymatic hydrolysis yield, reduces particle size of corn slurry and could be a potential effective pretreatment for corn slurry.