Adhesion of acorn barnacles on surface-active borate glasses

Concerns about the bioaccumulation of toxic antifouling compounds have necessitated the search for alternative strategies to combat marine biofouling. Because many biologically essential minerals have deleterious effects on organisms at high concentration, one approach to preventing the settlement of marine foulers is increasing the local concentration of ions that are naturally present in seawater. Here, we used surface-active borate glasses as a platform to directly deliver ions (Na + , Mg 2+ and BO 4 3− ) to the adhesive interface under acorn barnacles ( Amphibalanus ( =Balanus ) amphitrite ). Additionally, surface-active glasses formed reaction layers at the glass–water interface, presenting another challenge to fouling organisms. Proteomics analysis showed that cement deposited on the gelatinous reaction layers is more soluble than cement deposited on insoluble glasses, indicating the reaction layer and/or released ions disrupted adhesion processes. Laboratory experiments showed that the majority (greater than 79%) of adult barnacles re-attached to silica-free borate glasses for 14 days could be released and, more importantly, barnacle larvae did not settle on the glasses. The formation of microbial biofilms in field tests diminished the performance of the materials. While periodic water jetting (120 psi) did not prevent the formation of biofilms, weekly cleaning did dramatically reduce macrofouling on magnesium aluminoborate glass to levels below a commercial foul-release coating. This article is part of the theme issue ‘Transdisciplinary approaches to the study of adhesion and adhesives in biological systems’.

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Designing biomimetic antifouling surfaces

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2010.0195 ◽

2010 ◽

Vol 368 (1929) ◽

pp. 4729-4754 ◽

Cited By ~ 123

Author(s):

Maria Salta ◽

Julian A. Wharton ◽

Paul Stoodley ◽

Simon P. Dennington ◽

Liam R. Goodes ◽

...

Keyword(s):

Detrimental Effect ◽

Hydrodynamic Drag ◽

Biologically Inspired ◽

Marine Life ◽

Marine Biofouling ◽

Surface Active ◽

Fouling Organisms ◽

Operational Range ◽

Fuel Costs ◽

Naval Fleets

Marine biofouling is the accumulation of biological material on underwater surfaces, which has plagued both commercial and naval fleets. Biomimetic approaches may well provide new insights into designing and developing alternative, non-toxic, surface-active antifouling (AF) technologies. In the marine environment, all submerged surfaces are affected by the attachment of fouling organisms, such as bacteria, diatoms, algae and invertebrates, causing increased hydrodynamic drag, resulting in increased fuel consumption, and decreased speed and operational range. There are also additional expenses of dry-docking, together with increased fuel costs and corrosion, which are all important economic factors that demand the prevention of biofouling. Past solutions to AF have generally used toxic paints or coatings that have had a detrimental effect on marine life worldwide. The prohibited use of these antifoulants has led to the search for biologically inspired AF strategies. This review will explore the natural and biomimetic AF surface strategies for marine systems.

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Sensing Electrochemical Signals Using a Nitrogen-Vacancy Center in Diamond

Nanomaterials ◽

10.3390/nano11020358 ◽

2021 ◽

Vol 11 (2) ◽

pp. 358

Author(s):

Hossein T. Dinani ◽

Enrique Muñoz ◽

Jeronimo R. Maze

Keyword(s):

Electric Field ◽

Electron Spin ◽

Electrolyte Solution ◽

High Sensitivity ◽

Theoretical Work ◽

Coherence Time ◽

Nitrogen Vacancy ◽

Local Concentration ◽

Concentration Of Ions ◽

Nv Center

Chemical sensors with high sensitivity that can be used under extreme conditions and can be miniaturized are of high interest in science and industry. The nitrogen-vacancy (NV) center in diamond is an ideal candidate as a nanosensor due to the long coherence time of its electron spin and its optical accessibility. In this theoretical work, we propose the use of an NV center to detect electrochemical signals emerging from an electrolyte solution, thus obtaining a concentration sensor. For this purpose, we propose the use of the inhomogeneous dephasing rate of the electron spin of the NV center (1/T2★) as a signal. We show that for a range of mean ionic concentrations in the bulk of the electrolyte solution, the electric field fluctuations produced by the diffusional fluctuations in the local concentration of ions result in dephasing rates that can be inferred from free induction decay measurements. Moreover, we show that for a range of concentrations, the electric field generated at the position of the NV center can be used to estimate the concentration of ions.

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Specific Binding of Rubidium in Chlorella

The Journal of General Physiology ◽

10.1085/jgp.45.5.959 ◽

1962 ◽

Vol 45 (5) ◽

pp. 959-977 ◽

Cited By ~ 18

Author(s):

Dan Cohen

Keyword(s):

Active Transport ◽

Binding Sites ◽

Specific Binding ◽

High Concentration ◽

External Concentration ◽

Specific Binding Sites ◽

Dense Suspension ◽

Concentration Of Ions ◽

The Individual ◽

A Site

Specific binding sites for potassium, which may be components of the carriers for active transport for K in Chlorella, were characterized by their capacity to bind rubidium. A dense suspension was allowed to take up Rb86 from a low concentration of Rb86 and a high concentration of ions which saturate non-specific sites. The amount bound was derived from the increase in the external concentration of Rb86 following addition of excess potassium. The sites were heterogeneous. The average affinity of Rb and various other ions for the sites was determined by plotting the degree of displacement of Rb86 against log molar concentration of the individual ions. Interpolation gave the concentration for 50 per cent displacement of Rb, which is inversely related to affinity. The order of affinity was not changed when the cells were frozen, or boiled either in water or in 70 per cent ethanol. The affinity is maximal for ions with a crystalline radius of 1.3 to 1.5 A and a high polarizability, and is not related to the hydrated radius or valency. It is suggested that binding groups in a site are rigidly arranged, the irregular space between them being 2.6 to 3.0 A across, so that affinity is high for ions of this diameter and high polarizability.

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Extended Downhole Protection by Preservative Biocides as Demonstrated in High Pressure, High Temperature Bioreactors

10.2118/204377-ms ◽

2021 ◽

Author(s):

Joseph Ferrar ◽

Philip Maun ◽

Kenneth Wunch ◽

Joseph Moore ◽

Jana Rajan ◽

...

Keyword(s):

High Pressure ◽

High Temperature ◽

Active Ingredient ◽

Detectable Level ◽

High Concentration ◽

Similar Time ◽

High Pressure High Temperature ◽

Surface Active ◽

Shale Reservoirs ◽

Biocide Treatment

Abstract Preservative biocides are designed to control microbial growth and biogenic souring in the downhole environment. We report the prevention of biogenic souring by 4,4-dimethyloxazolidine (DMO, a preservative biocide) and glutaraldehyde as compared to that afforded by tributyl tetradecyl phosphonium chloride (TTPC, a cationic surface-active biocide), in a first-of-its kind suite of High Pressure, High Temperature (HPHT) Bioreactors that simulate hydraulically fractured shale reservoirs. The design of these new bioreactors, which recreate the downhole environment (temperatures, pressures, formation solids, and frac additives) in a controlled laboratory environment, enables the evaluation of biocides under field-relevant conditions. The bioreactors receiving either no biocide treatment or treatment with a high concentration of TTPC (50 ppm active ingredient) rapidly soured within the first two weeks of shut-in, and all surpassed the maximum detectable level of H2S (343 ppm) after the addition of live microbes to the reactors. Conversely, a higher loading of DMO (150 pppm active ingredient) maintained H2S concentrations below the minimum dectable level (5 ppm) for six weeks, and held H2S concentrations to 10.3 +/- 5.2 ppm after fifteen weeks of shut-in and two post shut-in microbial rechallenges. In a second study, a lower concentration of DMO (50 ppm active ingredient) maintained H2S concentrations below the minimum detectable level through the addition of live microbes after three weeks, and H2S concentrations only registered above 10 ppm upon a second addition of live microbes after five weeks. In this same study (which was performed at moderate temperatures), a 50 ppm (active ingredient) treatment of glutaraldehyde also maintained H2S concentrations below the minimum detectable level through the addition of live microbes after three weeks, and H2S concentrations registered 15.0 +/- 9.7 ppm H2S after four weeks. Similar time scales of protection are observed for each treatment condition through the enumeration of microbes present in each reactor. The differentiation in antimicrobial activity (and specifically, prevention of biogenic souring) afforded by DMO and glutaraldehyde suggests that such nonionic, preservative biocides are a superior choice for maintaining control over problematic microorganisms as compared to surface-active biocides like TTPC at the concentrations tested. The significant duration of efficacy provided by DMO and glutaraldehyde in this first-of-its-kind suite of simulated reservoirs demonstrates that comprehensive preservation and prevention of biogenic souring from completion through to production is feasible. Such comprehensive, prolonged protection is especially relevant for extended shut-ins or drilled but uncompleted wells (DUCS) such as those experienced during the COVID-19 pandemic. The environment simulated within the bioreactors demonstrates that the compatibility afforded by a preservative biocide offers downhole protection that cationic, surface-active biocides do not.

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The effects of surfactants on drop deformation and breakup

Journal of Fluid Mechanics ◽

10.1017/s0022112090003226 ◽

1990 ◽

Vol 220 ◽

pp. 161-186 ◽

Cited By ~ 263

Author(s):

H. A. Stone ◽

L. G. Leal

Keyword(s):

Equation Of State ◽

Interfacial Tension ◽

Active Material ◽

Interfacial Area ◽

Boundary Integral ◽

Boundary Integral Method ◽

Drop Deformation ◽

Local Concentration ◽

Interfacial Velocity ◽

Surface Active

The effects of surface-active agents on drop deformation and breakup in extensional flows at low Reynolds numbers are described. In this free-boundary problem, determination of the interfacial velocity requires knowledge of the distribution of surfactant, which, in turn, requires knowledge of the interfacial velocity field. We account for this explicit coupling of the unknown drop shape and the evolving surfactant distribution. An analytical result valid for nearly spherical distortions is presented first. Finite drop deformation is studied numerically using the boundary-integral method in conjunction with the time-dependent convective–diffusion equation for surfactant transport. This procedure accurately follows interfacial tension variations, produced by non-uniform surfactant distribution, on the evolving interface. The numerical method allows for an arbitrary equation of state relating interfacial tension to the local concentration of surfactant, although calculations are presented only for the common linear equation of state. Also, only the case of insoluble surfactant is studied.The analytical and numerical results indicate that at low capillary numbers the presence of surfactant causes larger deformation than would occur for a drop with a constant interfacial tension equal to the initial equilibrium value. The increased deformation occurs owing to surfactant being swept to the end of the drop where it acts to locally lower the interfacial tension, which therefore requires increased deformation to satisfy the normal stress balance. However, at larger capillary numbers and finite deformations, this convective effect competes with ‘dilution’ of the surfactant due to interfacial area increases. These two different effects of surface-active material are illustrated and discussed and their influence on the critical capillary number for breakup is presented.

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Water quality in a small network - problems and a proposal for their solution

Water Practice & Technology ◽

10.2166/wpt.2009.048 ◽

2009 ◽

Vol 4 (3) ◽

Cited By ~ 1

Author(s):

D. Kowalski

Keyword(s):

Water Quality ◽

Water Loss ◽

Cost Estimation ◽

Relevant Literature ◽

Field Tests ◽

Lead Contamination ◽

High Concentration ◽

Supply Networks ◽

Water Companies ◽

Water Outflow

The paper deals with the problem of deterioration of water quality in water supply networks. On the basis of relevant literature and his own research, the author points to a common occurrence of this phenomenon. The case study of a 3.5 km town network presented in the paper confirms the situation. The field tests of the water quality in that network detected a high concentration of iron and presence of lead contamination from PVC pipes. One of the methods of counteracting water quality deterioration used by water companies is flushing, accomplished as water outflow by fire hydrants. Unfortunately this method has several disadvantages, such as substantial water loss and the resulting costs. These factors dictate limitation of the flushing frequency as well of the duration of the process. In addition, the house pipes are not flushed at all. As a conceptual solution to this problem the author proposes, is the implementation of mobile flushing stations. The closed cycle applied during the flushing process can essentially reduce the water loss. The proposed solution has been tested by computer simulations. A simplified cost estimation of the implementation of the solution has also been presented.

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Effect of hydrogel on the turf grass species growing under salt stress

Annals of Warsaw University of Life Sciences – SGGW Land Reclamation ◽

10.2478/v10060-008-0092-4 ◽

2011 ◽

Vol 43 (1) ◽

pp. 47-55 ◽

Cited By ~ 2

Author(s):

Hadam Anna ◽

Wrochna Mariola ◽

Karaczun Zbigniew

Keyword(s):

Salt Stress ◽

Matter Content ◽

Point Of View ◽

Grass Species ◽

High Concentration ◽

Fresh Matter ◽

Turf Grass ◽

The Road ◽

Concentration Of Ions ◽

Main Factor

Effect of hydrogel on the turf grass species growing under salt stress Hydrogels can absorb huge amount of water and so are able to decrease the drought stress in plants. They are used in horticulture and agriculture for years. It is possible that they may be applied also on the grass near - road areas. Because of water deficient and high salinity growth of plants in these conditions is however hard. Meanwhile, too high concentration of ions in soil can decrease efficacy of hydrogel, since it can absorb water and cations as well. Nevertheless there is still too less studies on such problem. From this point of view it seems that the complex assessment of hydrogels effect on urban lawn grass is needed. The aim of the study was therefore the evaluation of grasses condition after their cultivation under salt stress with and without hydrogels amendment. Experience was conducted for four months in the controlled green house conditions. The efficacy of hydrogels amendment was measured by the grass reactions (turfs height, fresh matter content and level of membranes injury) on three levels of salinity. The results allowed concluding that, concentration of the road de- icing salt was the main factor, which affected condition of all tested species. This reaction was independent on the presence of hydrogel. Nevertheless under low and medium saline conditions watersorbent weakened significantly influence of salt stress on the grass.

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Present Status of Research and Application of Chemical Combination Flooding Technique and its Future

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.396-398.1248 ◽

2011 ◽

Vol 396-398 ◽

pp. 1248-1259 ◽

Cited By ~ 3

Author(s):

You Yi Zhu ◽

Qing Feng Hou ◽

Guo Qing Jian ◽

De Sheng Ma

Keyword(s):

Oil Recovery ◽

Field Tests ◽

Development Trend ◽

Current Status ◽

High Concentration ◽

Water Emulsion ◽

Asp Flooding ◽

Chemical Combination ◽

Combination System ◽

Pilot Tests

Chemical combination flooding technique is one of EOR techniques. The current status of chemical combination flooding including EOR mechanism, formula study, field test and application have been introduced and discussed. The problems met in field tests and future development trend of chemical combination flooding are directed. Synergistic effect among alkali, surfactant and polymer in ASP combination flooding, can improve both displacing efficiency and swept efficiency due to the increase of viscosity of displacing liquid and decrease in interfacial tension between oil and water. Emulsion ability of the chemical combination system can also improve the displacing efficiency. In addition, viscoelasticity of the combination system is also beneficial to improve the displacing efficiency. There are two main research tendencies for the formula system of chemical combination flooding. One is the high concentration small slug size system leaded by U.S., which can get high oil recovery but the cost is high. The other is a low concentration large slug size system leaded by China, which has good results and relatively low cost. With recent development of new polymers and surfactants, the chemical combination flooding has been will be widely used in different reservoirs. Pilot tests of ASP flooding in China have increased the oil recovery significantly. And such process has been extended to industrial tests and application. A serial of technologies has formed during ASP flooding field tests. Two main problems are shorter pump-checking period and higher cost of produced liquid handing. In order to avoid the negative effect of alkali, SP flooding pilot tests have been deployed. The general trend of chemical combination flooding technique is changing from strong-alkali ASP flooding to weak-alkali ASP flooding and alkali-free SP flooding. The application target reservoirs have extended from integral sandstone reservoirs to conglomerate reservoirs, complicated fault block reservoirs and carbonate reservoirs, from low temperature and low salinity reservoirs to high temperature and high salinity reservoirs.

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