scholarly journals Rhodochrosite Oxidation by Dissolved Oxygen and the Formation of Mn Oxide Product: The Impact of Goethite as a Foreign Solid Substrate

2021 ◽  
Author(s):  
Seonyi Namgung ◽  
Giehyeon Lee
Keyword(s):  
Dissolved Oxygen ◽  
Solid Substrate ◽  
Oxide Product ◽  
Mn Oxide ◽  
The Impact

Evaluation of Toxicity in Receiving Streams

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2357-2360
Author(s):  
J. Zagorc-Koncan ◽  
M. Dular
Keyword(s):  
Dissolved Oxygen ◽  
Toxic Substances ◽  
Toxicity Evaluation ◽  
Copper Cyanide ◽  
Polluted River ◽  
Design Information ◽  
Point Of Entry ◽  
Receiving Stream ◽  
The Impact

A laboratory river model for the study of self-purification inhibition in a stream containing toxic substances is presented. It enables an engineering - technological prediction of the impact of toxic substances or wastewaters on dissolved oxygen (DO) profile in an organically polluted river downstream from the point of entry of toxic effluent thus providing rapidly and inexpensively significant design information to an environmental scientist or engineer. The method was applied to the toxicity evaluation of wastewaters from electroplating industry. The effects of copper, cyanide (representing two significant constituents of this type of wastewaters) and wastewater from electroplating industry on the biodegradation of organic municipal pollution in receiving stream were evaluated experimentally.

Considering the impact of intermittent discharges when modelling overflows

1998 ◽  
Vol 38 (10) ◽  
pp. 23-30
Author(s):  
Sarah Jubb ◽  
Philip Hulme ◽  
Ian Guymer ◽  
John Martin
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Preliminary Investigation ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Combined Sewer Overflows ◽  
River Hydraulics ◽  
Combined Sewer ◽  
The Impact ◽  
Curve Equation

This paper describes a preliminary investigation that identified factors important in the prediction of river water quality, especially regarding dissolved oxygen (DO) concentration. Intermittent discharges from combined sewer overflows (CSOs) within the sewerage, and overflows at water reclamation works (WRW) cause dynamic conditions with respect to both river hydraulics and water quality. The impact of such discharges has been investigated under both wet and dry weather flow conditions. Data collected from the River Maun, UK, has shown that an immediate, transient oxygen demand exists downstream of an outfall during storm conditions. The presence of a delayed oxygen demand has also been identified. With regard to modelling, initial investigations used a simplified channel and the Streeter-Phelps (1925) dissolved oxygen sag curve equation. Later, a model taking into account hydrodynamic, transport and dispersion processes was used. This suggested that processes other than water phase degradation of organic matter significantly affect the dissolved oxygen concentration downstream of the location of an intermittent discharge. It is proposed that the dynamic rate of reaeration and the sediment oxygen demand should be the focus of further investigation.

scholarly journals Citizen Science Tools Reveal Changes in Estuarine Water Quality Following Demolition of Buildings

2021 ◽  
Vol 13 (9) ◽  
pp. 1683
Author(s):  
Nandini Menon ◽  
Grinson George ◽  
Rajamohananpillai Ranith ◽  
Velakandy Sajin ◽  
Shreya Murali ◽  
...  
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Citizen Science ◽  
Secchi Depth ◽  
Lake Water Quality ◽  
Demolition Waste ◽  
Water Colour ◽  
Water Quality Variables ◽  
The Impact

Turbidity and water colour are two easily measurable properties used to monitor pollution. Here, we highlight the utility of a low-cost device—3D printed, hand-held Mini Secchi disk (3DMSD) with Forel-Ule (FU) colour scale sticker on its outer casing—in combination with a mobile phone application (‘TurbAqua’) that was provided to laymen for assessing the water quality of a shallow lake region after demolition of four high-rise buildings on the shores of the lake. The demolition of the buildings in January 2020 on the banks of a tropical estuary—Vembanad Lake (a Ramsar site) in southern India—for violation of Indian Coastal Regulation Zone norms created public uproar, owing to the consequences of subsequent air and water pollution. Measurements of Secchi depth and water colour using the 3DMSD along with measurements of other important water quality variables such as temperature, salinity, pH, and dissolved oxygen (DO) using portable instruments were taken for a duration of five weeks after the demolition to assess the changes in water quality. Paired t-test analyses of variations in water quality variables between the second week of demolition and consecutive weeks up to the fifth week showed that there were significant increases in pH, dissolved oxygen, and Secchi depth over time, i.e., the impact of demolition waste on the Vembanad Lake water quality was found to be relatively short-lived, with water clarity, colour, and DO returning to levels typical of that period of year within 4–5 weeks. With increasing duration after demolition, there was a general decrease in the FU colour index to 17 at most stations, but it did not drop to 15 or below, i.e., towards green or blue colour indicating clearer waters, during the sampling period. There was no significant change in salinity from the second week to the fifth week after demolition, suggesting little influence of other factors (e.g., precipitation or changes in tidal currents) on the inferred impact of demolition waste. Comparison with pre-demolition conditions in the previous year (2019) showed that the relative changes in DO, Secchi depth, and pH were very high in 2020, clearly depicting the impact of demolition waste on the water quality of the lake. Match-ups of the turbidity of the water column immediately before and after the demolition using Sentinel 2 data were in good agreement with the in situ data collected. Our study highlights the power of citizen science tools in monitoring lakes and managing water resources and articulates how these activities provide support to Sustainable Development Goal (SDG) targets on Health (Goal 3), Water quality (Goal 6), and Life under the water (Goal 14).

scholarly journals Numerical Analysis of the Impact on Dissolved Oxygen by the Breakwater in Ofunato Bay

2014 ◽  
Vol 70 (2) ◽  
pp. I_421-I_425
Author(s):  
Ken FURUDOI ◽  
Shigeki SAKAI ◽  
Kazuo MURAKAMI ◽  
Yoshiyuki NAKAMURA ◽  
Ikuo ABE ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Dissolved Oxygen ◽  
The Impact

scholarly journals Numerical Simulations of the Impact and Spreading of a Particulate Drop on a Solid Substrate

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Hyun Jun Jeong ◽  
Wook Ryol Hwang ◽  
Chongyoup Kim
Keyword(s):  
Numerical Simulations ◽  
Solid Surface ◽  
Reynolds Numbers ◽  
Suspended Particles ◽  
Solid Substrate ◽  
Oscillatory Behavior ◽  
Navier Stokes ◽  
Droplet Spreading ◽  
Navier Stokes Equation ◽  
The Impact

We present two-dimensional numerical simulations of the impact and spreading of a droplet containing a number of small particles on a flat solid surface, just after hitting the solid surface, to understand particle effects on spreading dynamics of a particle-laden droplet for the application to the industrial inkjet printing process. The Navier-Stokes equation is solved by a finite-element-based computational scheme that employs the level-set method for the accurate interface description between the drop fluid and air and a fictitious domain method for suspended particles to account for full hydrodynamic interaction. Focusing on the particle effect on droplet spreading and recoil behaviors, we report that suspended particles suppress the droplet oscillation and deformation, by investigating the drop deformations for various Reynolds numbers. This suppressed oscillatory behavior of the particulate droplet has been interpreted with the enhanced energy dissipation due to the presence of particles.

scholarly journals Impact of Global Warming on Dissolved Oxygen and BOD Assimilative Capacity of the World’s Rivers: Modeling Analysis

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2408
Author(s):  
Steven C. Chapra ◽  
Luis A. Camacho ◽  
Graham B. McBride
Keyword(s):  
Dissolved Oxygen ◽  
Natural Waters ◽  
Cold Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Assimilative Capacity ◽  
Mountainous Regions ◽  
Modeling Analysis ◽  
Lower Oxygen ◽  
The Impact

For rivers and streams, the impact of rising water temperature on biochemical oxygen demand (BOD) assimilative capacity depends on the interplay of two independent factors: the waterbody’s dissolved oxygen (DO) saturation and its self-purification rate (i.e., the balance between BOD oxidation and reaeration). Although both processes increase with rising water temperatures, oxygen depletion due to BOD oxidation increases faster than reaeration. The net result is that rising temperatures will decrease the ability of the world’s natural waters to assimilate oxygen-demanding wastes beyond the damage due to reduced saturation alone. This effect should be worse for nitrogenous BOD than for carbonaceous BOD because of the former’s higher sensitivity to rising water temperatures. Focusing on streams and rivers, the classic Streeter–Phelps model was used to determine the magnitude of the maximum or “critical” DO deficit that can be calculated analytically as a function of the mixing-point BOD concentration, DO saturation, and the self-purification rate. The results indicate that high-velocity streams will be the most sensitive to rising temperatures. This is significant because such systems typically occur in mountainous regions where they are also subject to lower oxygen saturation due to decreased oxygen partial pressure. Further, they are dominated by salmonids and other cold-water fish that require higher oxygen levels than warm-water species. Due to their high reaeration rates, such systems typically exhibit high self-purification constants and consequently have higher assimilation capacities than slower moving lowland rivers. For slow-moving rivers, the total sustainable mixing-point concentration for CBOD is primarily dictated by saturation reductions. For faster flowing streams, the sensitivity of the total sustainable load is more equally dependent on temperature-induced reductions in both saturation and self-purification.

Experiments on the breakup of drop-impact crowns by Marangoni holes

2018 ◽  
Vol 844 ◽  
pp. 162-186 ◽  
Author(s):  
Abdulrahman B. Aljedaani ◽  
Chunliang Wang ◽  
Aditya Jetly ◽  
S. T. Thoroddsen
Keyword(s):  
Surface Tension ◽  
Lower Surface ◽  
High Viscosity ◽  
Solid Substrate ◽  
Immiscible Liquid ◽  
Hole Formation ◽  
Low Viscosity ◽  
Stress Changes ◽  
Lower Surface Tension ◽  
The Impact

We investigate experimentally the breakup of the Edgerton crown due to Marangoni instability when a highly viscous drop impacts on a thin film of lower-viscosity liquid, which also has different surface tension than the drop liquid. The presence of this low-viscosity film modifies the boundary condition, giving effective slip to the drop along the solid substrate. This allows the high-viscosity drop to form a regular bowl-shaped crown, which rises vertically away from the solid and subsequently breaks up through the formation of a multitude of Marangoni holes. Previous experiments have proposed that the breakup of the crown results from a spray of fine droplets ejected from the thin low-viscosity film on the solid, e.g. Thoroddsen et al. (J. Fluid Mech., vol. 557, 2006, pp. 63–72). These droplets can hit the inner side of the crown forming spots with lower surface tension, which drives a thinning patch leading to the hole formation. We test the validity of this assumption with close-up imaging to identify individual spray droplets, to show how they hit the crown and their lower surface tension drive the hole formation. The experiments indicate that every Marangoni-driven patch/hole is promoted by the impact of such a microdroplet. Surprisingly, in experiments with pools of higher surface tension, we also see hole formation. Here the Marangoni stress changes direction and the hole formation looks qualitatively different, with holes and ruptures forming in a repeatable fashion at the centre of each spray droplet impact. Impacts onto films of the same liquid, or onto an immiscible liquid, do not in general form holes. We furthermore characterize the effects of drop viscosity and substrate-film thickness on the overall evolution of the crown. We also measure the three characteristic velocities associated with the hole formation: i.e. the Marangoni-driven growth of the thinning patches, the rupture speed of the resulting thin films inside these patches and finally the growth rate of the fully formed holes in the crown wall.

Corrosion of Co in BEOL interconnects in dilute HF solution

2018 ◽  
Vol 282 ◽  
pp. 256-262
Author(s):  
Yuya Akanishi ◽  
Els Kesters ◽  
Quoc Toan Le ◽  
Frank Holsteyns
Keyword(s):  
Dissolved Oxygen ◽  
Etch Rate ◽  
Galvanic Corrosion ◽  
Barrier Structure ◽  
Corrosion Prevention ◽  
Atmospheric Air ◽  
The Impact

The impact of dissolved oxygen (O2) on cobalt (Co) corrosion in dilute HF (dHF) solution was studied. It was confirmed that Co etch rate was enhanced as the amount of dissolved O2 in the HF solution increased. The Co etch rate was also found to increase radially outward when performed on a single-wafer spin process in atmospheric air due to the uptake of O2 during the dispense process. The galvanic corrosion of Co was investigated with two types of structures with a Co/Cu interface in different dissolved O2 concentrations, i.e. (1) Co bump structures on Cu and (2) Cu lines with a Co/TaN liner/barrier structure. By controlling both the dissolved and the atmospheric O2 levels, galvanic corrosion prevention at the Co/Cu interface was achieved.

Anomalous transport of heat and salt by a long-lived anticyclonic eddy  in the northeast tropical Pacific Ocean

2021 ◽  
Author(s):  
Kaveh Purkiani ◽  
Maren Walter ◽  
Matthias Haeckel ◽  
Katja Schmidt ◽  
André Paul ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Dissolved Oxygen ◽  
Mesoscale Eddy ◽  
Tropical Pacific ◽  
Anticyclonic Eddy ◽  
Altimeter Data ◽  
Positive Temperature ◽  
Tropical Pacific Ocean ◽  
High Rotational Speed ◽  
The Impact

<p><span>During RV Sonne expedition SO268 to the northeast tropical Pacific Ocean between March and May 2019, the impact of a mesoscale eddy on the seawater properties was investigated by conducting a multiple of observations. A subsequent analysis of an altimeter data revealed the formation of an anticyclonic mesoscale eddy in the Tehuantepec gulf between 15 and 20 June 2018 with a mean radius of 185 km and an average speed of 13 cm/s. This extremely long-lived eddy carried sea-water characteristics from near coastal Mexican waters westward far into the open ocean. The water mass stayed largely isolated during the 11 months of travel time due to high rotational speed.</span></p><p><span>The eddy exhibited a conical-shape vertical structure with concurrent deepening of the main thermocline. The water in the eddy core showed an extreme positive temperature anomaly of 8</span><sup><span>◦</span></sup><span>C, a negative salinity anomaly of -0.5 psu and a positive dissolved oxygen concentration anomaly of +160 μmol/kg centered at 80 m depth. The sub-surface impact of the eddy is clearly evident in the temperature and salinity profiles at a depth of 1500 m. For dissolved oxygen the eddy-induced anomaly reached even deeper to the seafloor.</span></p><p><span>This study provides new insights to the offshore transport of heat and salt driven by the long-lived anticyclonic eddy in the northeast tropical Pacific Ocean. Considering the water column trapped within the eddy, a positive heat transport anomaly of 1-3 ×10</span><sup><span>11</span></sup><span> W and a negative salt transport anomaly of -8×10</span><sup><span>3</span></sup><span> kg/s were estimated. However, due to the rare occurrence of long-lived anticyclone eddies in this region, they likely do not play a significant role in affecting the heat and salt balance of the northeastern tropical Pacific Ocean. </span></p>

scholarly journals Bioprocess considerations for T‐cell therapy: Investigating the impact of agitation, dissolved oxygen, and pH on T‐cell expansion and differentiation

2020 ◽  
Vol 117 (10) ◽  
pp. 3018-3028 ◽  
Author(s):  
Arman Amini ◽  
Vincent Wiegmann ◽  
Hamza Patel ◽  
Farlan Veraitch ◽  
Frank Baganz
Keyword(s):  
T Cell ◽  
Cell Therapy ◽  
Dissolved Oxygen ◽  
Cell Expansion ◽  
T Cell Therapy ◽  
T Cell Expansion ◽  
The Impact
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