Effect Of Water Flow Rate Research Articles

Development of High-Speed and Large-Scale Culture Technology of Marine Algae Using Seawater With High Concentrations of Dissolved Carbon Dioxide

The effective use of marine biomass has recently been identified as a feasible method of renewable energy production. Therefore, to facilitate the effective use of algae biomass, it is essential to develop techniques for the mass production of algal cultures. It is also important to develop artificial culture techniques that are not affected by natural phenomena such as weather. This study utilized a newly developed culture technology that uses seawater with high concentrations of dissolved CO2 (CO2 seawater). The experiments in this study were conducted to test the effects of CO2 seawater on algal growth. In addition to experimental conditions that were previously investigated in industrial algae farming scenarios, it is also necessary to consider the effects of new parameters associated with increased CO2 concentrations. The following four conditions were experimentally investigated: (1) the tolerance of algae to changes in pH, (2) the effect of CO2 seawater on long-term culture growth, (3) the effect of continuous culture experiments, and (4) the effect of water flow rate on cultured algae. The results in terms of having excelled especially indicate that a 1-month long-term algae culture period in seawater with CO2 concentration of 1.0% led to growth that was approximately 4.5 times faster than growth in seawater without the CO2 additive. Furthermore, the results also provided useful information regarding the proper flow rate needed to enhance algal growth.

Hydrolysis and oxidation of sodium toluene sulfonate in sub-/supercritical water in the presence of CO2 or H2O2

The hydrolysis of sodium toluene sulfonate (STS) in sub-/supercritical water in the presence of CO2 was investigated using a continuous flow system at the constant pressure of 250bar. The effect of water flow-rates, reaction temperature and CO2 flow-rates on the hydrolysis of STS was investigated. Results showed that hydrolysis of STS increases with the increase in temperature and CO2 flow rate. The optimum reaction conditions calculated by partial factorial design were 452°C, water flow rate of 2.3mLmin−1 and CO2 flow rate of 0.08mLmin−1. Furthermore, supercritical water was used for total removal of STS from industrial wastewater using H2O2 as an oxidant. Results showed that at temperatures higher than 350°C more than 99% of STS is oxidized while COD remains high until reaction temperature of 450°C after which COD of solution diminished 81%.

Effect of water flow rate on polyculture of koi carp (Cyprinus carpio var. koi) and goldfish (Carassius auratus) with water spinach (Ipomoea aquatica) in recirculating aquaponic system

A 45-day experiment was conducted for standardization of water flow rate for koi carp (Cyprinus carpio var. koi) and gold fish (Carassius auratus) along with water spinach (Ipomoea aquatica) in water recirculating aquaponic system. Different flow rates, viz., 0.8, 2.4, and 4 l min−1, were assigned as T1, T2, and T3, respectively, with stocking density ratio of 1:2 for koi carp and goldfish. Treatment T1 showed maximum fish growth in terms of percentage weight gain and specific growth rate. Plant height, percentage height gain, and yield of water spinach plants were observed highest in treatment T1 as compared to T2 and T3. All the treatments effectively removed nutrients, but treatment T1 showed maximum percentage of nutrient removal (NO3-N, PO4-P, and K). The plant growth and nutrient removal were increased with decrease in flow rate. Flow rate in T1 (0.8 l min−1) showed the highest growth in both fish species. Thus, 0.8 l min−1 can be suggested as optimum water flow rate for the polyculture of koi carp and goldfish with water spinach in an aquaponic system.

An Electrochemical Impedance Spectroscopy Study and Two Phase Flow Analysis of the Anode of Polymer Electrolyte Membrane Water Electrolysers

The effect of water flow rate on the performance of a polymer electrolyte membrane water electrolyser (PEMWE) was studied using an unpressurised lab-scale (25 cm2) cell. The linear polarisation curves obtained showed a voltage increase at higher current densities that increased with water flow rate. Electrochemical impedance spectroscopy (EIS) showed that while lower water flow rates lead to higher cell temperatures and reduced membrane resistance, mass transport losses dominate at high current density. As the water flow is exclusively in the bubbly regime, increase in mass transport limitation is attributed to bubble formation dynamics and reduced gas void fraction at higher water flow rates. Figure 1

Determinacion del flujo de agua para la biorremediacion en sistemas recirculados acuaculturales utilizando tapetes microbianos construidos

The effect of water flow rate was evaluated on the microbial mats efficiency to remove total ammonia nitrogen (TAN, NH4 + -N+ NH3-N), nitrite (N-NO2 - ), nitrate (N-NO3 - ) and orthophosphate (P-PO4 -3 ) in a pilot recirculation system for the culture of the Pacific white shrimp, Litopenaeus vannamei. Four water flow rates were evaluated during 40 days: 5.2 ± 0.3 (A), 6.6 ± 1.3 (B), 8.4 ± 0.3 (C), and 12.2 ± 0.7 (D) L min -1 . The concentrations of TAN and nitrites were significantly lower (P 0.05). No differences in the removal of orthophosphate between treatments (P > 0.05) were found, and their concentration in the culture systems reached values of 4.63 ± 0.76 mg L -1 . The growth rate of shrimp remained close to the expected value of 0.7 g week -1 . This study showed that the water flow rate has a significant effect on the microbial mats capacity for the bioremediation of ammonium and nitrite in recirculating systems. It is recommended to continue with the identification of other variables that could affect the optimal functioning of microbial mats in RAS.

Electrochemical Production of 70 wt ppm Ozone Water

The effects of water flow rate and current density on the ozone concentration in anode water were investigated using a new electrochemical ozone production (EOP) system. The absorption coefficient of O3 at 290nm in water was found to be 720L mol−1cm−1, about twice as large as that in the gas phase, 374L mol−1cm−1. The O3 concentration increased with increasing current density and decreasing anode water flow rate. The highest O3 concentration of 70wtppm was observed when the water flow rate was 100mL/min, the current density was 2.13A/cm2, and the cell pressure was 0.2MPa. This concentration is the highest reported for a once-through EOP system. As the anode water flow rate decreased, the current efficiency of O3 production also decreased owing to the formation of O3 and O2 gases, which reduce the catalytically active area of the Pt anode. The high current efficiency of 29.1% at a water flow rate of 820mL/min decreased to as low as 6.7% at 92mL/min. The results of pressure dependence measurements of the current efficiency of O3 production and the O3 concentration in anode water suggest that high-pressure operation has a slightly positive effect on them.

A Numerical Study Onfire Suppression of Water Mist in Microgravity

Water mist technology has been developed and regarded as a promising substitute fire-extinguishing agent in spacecraft. In this paper, a numerical simulation method is introduced to investigate the effect of water mist size, velocity and flow rateon the fire suppressionefficiencyin microgravity. The fire extinguishing efficiency is better for the finer water mist in microgravity due to better heat transfer and more rapid vaporization. The evaporation cooling is the dominant mechanism of fire suppression in microgravity.As for the water mist velocity, the performance of fire suppression is affected slightly in microgravity. The results on the effect of water flow rate show that the flow rate should be higher than a critical value to suppress the fire effectively.

Effect of water flow rates on growth of Cyprinus carpio var. koi (Cyprinus carpio L., 1758) and spinach plant in aquaponic system

The experiment was aimed at standardization of water flow rate in aquaponic system in order to correlate nutrient removal and water quality with growth of Cyprinus carpio var. koi (koi carp fingerlings) and Beta vulgaris var. bengalensis (spinach). Different flow rates, i.e., 3.2, 1.5, and 1.0 l min−1, were assigned as treatments T1, T2, and T3, respectively, with spinach plants (28 plant m−2), whereas S1 and S2 were the treatments having flow rates of 1.5 and 1.0 l min−1, respectively, without plants. Control (C) was set at flow rates of 3.2 l min−1 without plants. Treatment T2 (1.5 l min−1) showed highest weight gain of koi carp fingerlings and also height gain of spinach plants as compared to other treatments. There was no significant difference in length gain, percentage weight gain, specific growth rate, feed conversion ratio, feed efficiency ratio, and protein efficiency ratio as compared to other treatments and control. All the treatments, T1, T2, and T3, effectively remove nitrate (77–78 %), phosphate (47.04–55.06 %), and potassium (22.85–29.16 %) from fish effluent tanks. These results suggest that flow rates 3.2, 1.5, and 1.0 l min−1 were effective under aquaponic system. Of which, 1.5 l min−1 can be suggested as optimum water flow rate for the growth of spinach and koi carp in aquaponic system as percentage weight gain in fish, percentage height gain, and yield of plants were higher compared to flow rates 3.2 and 1.0 l min−1.

Effect of Water Flow Rate on Decontamination Efficiency of Emergency Safety Showers

AbstractStandards for overhead emergency safety showers used for decontamination in laboratories and production sites specify the spray pattern and the water flow rate. Up to now, there has not been a scientific basis for these requirements. The decontamination of water‐soluble contaminants has been investigated using 15 customary shower heads at different water flow rates. A general relationship between water flow rate and decontamination effectiveness could not be established: At a low flow rate, the wash‐off time in general did not exceed the time observed at considerably higher flow rates. The shortest decontamination time has been found with a spray pattern that does not fulfil current standards.

Insights into transport velocity of colloid-associated plutonium relative to tritium in porous media.

Although faster transport velocities of colloid-associated actinides, bacteria, and virus than nonreactive solutes have been observed in laboratory and field experiments, some questions still need to be answered. To accurately determine the relative velocity (UPu/UT) of 239Pu and tritium representative of the bulk water, a conceptual model of electrostatic interactions coupled with the parabolic water velocity profile in pore channels is developed. Based on the expression for UPu/UT derived from this model, we study the effects of water flow rates and ionic strengths on the UPu/UT. Also, the velocity relationship between Pu, tritium and Sr2+ is explored. The results show that UPu/UT increased fairly linearly with decreasing water flow rates; UPu/UT declined approximately exponentially with increasing Na+ concentrations; the charge properties of colloid-associated Pu (negative), tritium (neutral) and Sr2+ (positive) had a close association with their transport velocities as UPu : UT : USr2+ = 1.41 : 1 : 0.579.

Experimental study of gas evolution in heterogeneous shallow subsurface formations during leakage of stored CO2

A concern for geologic carbon sequestration is the potential for stored CO2 to leak upward into valuable shallow aquifers where it can cause potentially detrimental impacts to groundwater resources. Understanding the mechanisms of CO2 migration and predicting its movement in shallow aquifers is a critical part of determining those impacts. During leakage, CO2 dissolved in brines may travel upward, potentially causing the gas to be released from solution (exsolve). Exsolved gas may accumulate at soil layer transitions, or flow into the vadose zone and ultimately the atmosphere. For this study, a series of intermediate-scale laboratory experiments were conducted to observe CO2 gas evolution in heterogeneous porous media. Results indicate that: (1) heterogeneous interfaces as well as flow constrictions through discontinuities in low-permeability layers enhance the evolution of gas phase, provided the water pressure at those layers is less than the pressure at which the flowing water was saturated with CO2, (2) higher contrast between the sands in a 1-D heterogeneous system leads to faster gas evolution, and (3) the effects of water flow rate on the evolution of the gas phase are sensitive to two-dimensional water flow pattern fluctuations.

Techniques for Determining Small Fractions of Oil Components in the Sea Water Flow by Rotation of Vibration Plane

In this study, the results of the effect of water-flow rate and air fraction component on intensity, I, are presented and discussed. The study which was carried out at Bergen University in Norway, presents the impact of monochromatic defects on polarization and measurements of small oil fractions of various crude oils are presented. When there was refraction, it was observed that in static sea-water 38 = flow static µ µ and in both cases flow µ was

Effects of Water Flow Rate on Shear Bond Strength of Orthodontic Bracket Bonded to Enamel Surface After Er:YAG Laser Ablation

The aim of present study was to evaluate the effect of water flow rate on enamel surface roughness and shear bond strength (SBS) of orthodontic brackets after Er:YAG laser ablation. It is well known that external water supply is a fundamental requirement for Er:YAG laser efficiency on dental hard tissues. However, there is no consensus considering the water flow rate used during Er:YAG laser ablation. Eighty sound human upper premolar teeth were used in the present study. Seventy-six teeth were assigned into four groups according to surface treatments. The 37% phosphoric acid-etched group served as the control. Er:YAG laser irradiation was performed in three subgroups with water flow rates of 25, 36, and 48 mL/min, respectively. All specimens were subjected to a SBS test. One specimen from each different surface treatment modality was examined by scanning electron microscopy. Kruskal-Wallis test was used to compare the SBS value of each group. Although the control group had the highest SBS value, statistically no significant differences were found among groups. Er:YAG laser application with a water flow rate of 48 mL/min produced better enamel surface alterations without any thermal damage to yield higher SBS values.

Implant Fixture Heat Transfer During Abutment Preparation

The purpose of the study was to evaluate the effect of water flow rate on the heat transmission in implants during abutment preparation using a diamond bur in a high-speed dental turbine. Titanium-alloy abutments (n = 32) were connected to a titanium-alloy implant embedded in an acrylic resin within a water bath at a controlled temperature of 37°C. The specimens were equally distributed into 2 groups (16 each) according to the water flow rate used during the preparation phase. Group 1 had a water flow rate of 24 mL/min, and group 2 had a water flow rate of 40 mL/min. Each abutment was prepared in the axial plane for 1 minute and in the occlusal plane for 1 minute with a coarse tapered diamond bur using a high-speed dental handpiece. Thermocouples embedded at the cervix of the implant surface were used to record the temperature of heat transmission from the abutment preparation. Heat generation was measured at 3 distinct times (immediately and 30 seconds and 60 seconds after the end of preparation). Statistical analyses were carried out using 2-way analysis of variance and the Student t test. Water flow rates (24 mL vs 40 mL) and time interval had no statistically significant effect on the implant's temperature change during the abutment preparation stage (P = .431 and P = .064, respectively). Increasing the water flow rate from 24 to 40 mL/min had no influence on the temperature of the implant fixture recorded during preparation of the abutment.

Effect of Water Flow Rate on Decontamination Efficiency of Emergency Safety Showers

AbstractNormen für Überkopf‐Personennotduschen in Laboratorien und Betrieben zum Abspülen von Gefahrstoffkontaminationen stellen Anforderungen an das Sprühbild und an den Wasservolumenstrom – bislang ohne wissenschaftlich gesicherte Grundlage. In einer praxisorientierten Untersuchung an 15 anwendungsüblichen Duschköpfen wurde die Abspülwirkung für wasserlösliche Kontaminanten bei 20 bis 110 L min–1 Wasservolumenstrom untersucht. Ein Zusammenhang zwischen Wirkung und Volumenstrom konnte nicht gezeigt werden: Bei 30 L min–1 Wasser ist die Abspülzeit nicht generell länger als bei wesentlich höheren Volumenströmen. Die kürzeste Abspülzeit wurde an Notduschen mit nicht‐normkonformem Sprühbild gefunden.

Electrochemical Pre-Oxidation of Drinking Water by On-Site Electro-Generation of Hydrogen Peroxide

Hydrogen peroxide is a green oxidizer. On-site electrochemical production of hydrogen peroxide has potential to become a new way for raw water pre-oxidation. The performance of electro-generation hydrogen peroxide was studied in the electrochemical reactor equipped with graphite felt as cathode and RuO2-IrO2-coated titanium mesh as anode. The effect of water flow rate, air flow rate and current density on concentration of hydrogen peroxide and energy consumption was studied. Results indicate that the optimal condition for the lowest energy consumption is to directly produce 5 mg/L of hydrogen peroxide as compared with producing high concentration followed by dilution. It was found that electrochemical pre-oxidation technology had a good effect on sterilization and removing turbidity and stink for raw water.

Effect of Water Flow Rate and Stocking Density on Nursing Hatchery-Reared Juvenile Oysters, Crassostrea belcheri in a Semi-Closed Recirculation System

Juveniles of hatchery-reared oysters (Crassostrea belcheri) were grown in a semi-closed recirculation system at water flow rates of 0.5, 1, 2, and 4 l min−1. Growth rate increased with increasing water flow rate (P < 0.05) over four weeks. No significant differences in survival were found among water flow rates (P > 0.05). Four stocking density treatments were compared: 4, 8, 12, and 16 juveniles cm−2. Stocking density affected the growth of animals, with higher growth rates obtained at the lower densities. Optimum stocking density based on growth rate was obtained for oysters at 12 juveniles cm−2. Survival of oysters declined with increasing density (P < 0.05) over four weeks. Among the treatments tested, a water flow rate of 4 l min−1 and stocking density of 12 juveniles cm−2 are suitable for nursing hatchery-reared juvenile oysters (C. belcheri) in a semi-closed recirculation system.

Laboratory study on the adsorption of Mn2+ on suspended and deposited amorphous Al(OH)3 in drinking water distribution systems

Manganese (II) is commonly present in drinking water. This paper mainly focuses on the adsorption of manganese on suspended and deposited amorphous Al(OH)3 solids. The effects of water flow rate and water quality parameters, including solution pH and the concentrations of Mn2+, humic acid, and co-existing cations on adsorption were investigated. It was found that chemical adsorption mainly took place in drinking water with pHs above 7.5; suspended Al(OH)3 showed strong adsorption capacity for Mn2+. When the total Mn2+ input was 3 mg/L, 1.0 g solid could accumulate approximately 24.0 mg of Mn2+ at 15 °C. In drinking water with pHs below 7.5, because of H+ inhibition, active reaction sites on amorphous Al(OH)3 surface were much less. The adsorption of Mn2+ on Al(OH)3 changed gradually from chemical coordination to physical adsorption. In drinking water with high concentrations of Ca2+, Mg2+, Fe3+, and HA, the removal of Mn2+ was enhanced due to the effects of co-precipitation and adsorption. In solution with 1.0 mg/L HA, the residual concentration of Mn2+ was below 0.005 mg/L, much lower than the limit value required by the Chinese Standard for Drinking Water Quality. Unlike suspended Al(OH)3, deposited Al(OH)3 had a much lower adsorption capacity of 0.85 mg/g, and the variation in flow rate and major water quality parameters had little effect on it. Improved managements of water age, pipe flushing and mechanical cleaning were suggested to control residual Mn2+.

Experimental Study on Optimization of the Agglomeration Process for Producing Instant Sugar by Conical Fluidized Bed Agglomerator

This study was conducted to determine the optimal processing conditions for manufacturing instant sugar. The instant sugar was produced with a batch fluid bed agglomerator under the following conditions: inlet air temperature 60–90°C; water flow rate 1–3 mL min−1; and spraying time 1–10 min. The optimal conditions were estimated using response surface methodology as follows: inlet air temperature of 74.4°C, water flow rate of 2.85 mL min−1, and spraying time of 10 min. Subsequently, particle density of 1,550 kg m−3, poured density of 470.13 kg m−3, tapped density of 599.8 kg m−3, porosity of 62.1%, mean diameter of 324.66 µm, flowing time of 6.39 s, yield percentage of 78.96%, and desirability of 0.46 were obtained as optimal amounts. The results showed that the quadratic effects of water flow rate and spraying time on flowing time and particle density as well as the effects of spraying time and inlet air temperature on mean diameter and flowing time were significant. Within the temperature range of 60–90°C, the impact of spraying time and water flow rate on instant sugar properties had preference over inlet air temperature. Moreover, the optimal instant sugar required less dissolution time compare to various industrial sugar samples.

Water Flow Affects Zooplankton Feeding by the Scleractinian CoralGalaxea fascicularison a Polyp and Colony Level

Several factors may affect heterotrophic feeding of benthic marine invertebrates, including water flow rate and polyp context (i.e., the presence of neighbouring polyps). We tested the interactive effects of water flow rate and polyp context on zooplankton feeding by the scleractinian coralGalaxea fascicularis. Single polyps and colonies were incubated in a flow cell for 30 minutes with an ambientArtemianauplii concentration of 10,000 L−1and water flow rates ranging from 1.25 to 40 cm s−1. Water flow rate and polyp context showed significant main and interactive effects on feeding rates ofG. fascicularispolyps. More specifically, feeding rates were optimal at flow rates of 1.25 cm s−1for single polyps and 5 to 10 cm s−1for polyps inhabiting colonies. The presence of epizoic acoelomorph flatworms may have negatively affected the observed feeding rates, especially at high flow. Our results demonstrate that water flow affects coral feeding and thus heterotrophic nutrient input at both a polyp and colony level. These findings are of relevance to our understanding of how biotic and abiotic factors interact on coral heterotrophy and may serve to optimise coral aquaculture.