scholarly journals Crystal critters: Self-ejection of crystals from heated, superhydrophobic surfaces

2021 ◽  
Vol 7 (18) ◽  
pp. eabe6960
Author(s):  
Samantha A. McBride ◽  
Henri-Louis Girard ◽  
Kripa K. Varanasi
Keyword(s):  
Saline Water ◽  
Mass Conservation ◽  
Industrial Processes ◽  
Cooperative Effects ◽  
Materials Engineering ◽  
Evaporative Crystallization ◽  
Unusual Phenomenon ◽  
Minimal Contact ◽  
Water Drops ◽  
Asymmetric Growth

Mineral or crystal fouling (the accumulation of precipitants on a material and damage associated with the same) is a pervasive problem in water treatment, thermoelectric power production, and numerous industrial processes. Growing efforts have focused on materials engineering strategies (e.g., superhydrophobicity) to prevent fouling. Here, we present a curious phenomenon in which crystals self-eject from heated, nanotextured superhydrophobic materials during evaporation of saline water drops. These crystal structures (crystal critters) have exceedingly minimal contact with the substrate and thus pre-empt crystal fouling. This unusual phenomenon is caused by cooperative effects of crystallization, evaporative flows, and nanoscale effects. The temperature dependence of the critter effect can be predicted using principles of mass conservation, and we demonstrate that self-propulsion can be generated via temperature gradients, which promote asymmetric growth. The insights on confinement-driven evaporative crystallization can be applied for antifouling by self-ejection of mineral foulants, for drop-based fluidic machines, or even for self-propulsion.

scholarly journals EFFECT OF A SALINE SOLUTION ON GROWTH AND CHEMICAL COMPOSITION OF ATRIPLEX NUMMULARIA

2012 ◽  
Vol 09 (18) ◽  
pp. 73-86
Author(s):  
Eliane Gonçalves ARAÚJO ◽  
Márcia Lima SILVA ◽  
Francisco Nobre de Abrantes NETO ◽  
Sheila Priscila Marques CABRAL ◽  
Carlos Alberto MARTINEZ-HUITLE ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Optical Emission Spectroscopy ◽  
Saline Solution ◽  
Saline Water ◽  
Evolutionary Process ◽  
Chemical Characterization ◽  
Optical Emission ◽  
Industrial Processes ◽  
Atriplex Nummularia ◽  
Anions And Cations

This study aimed to analyze the effect of a saline solution on growth and chemical composition of Atriplex nummularia. These species seedlings were planted in the Garden of the Federal University of Rio Grande do Norte. Chemical characterization was performed using the Ion Chromatography (IC) and Optical Emission Spectroscopy (ICP-OES). The results of this analysis highlighted the diversity of anions and cations absorbed by the plant during its evolutionary process. Based on this study it was concluded that the Atriplex could be used as a source of absorbing salts from soils contaminated by effluents from industrial processes in which the saline water has as an end product of their processes.

scholarly journals Drowning-out crystallization of sodium molybdate in aqueous-ethanol solutions

2020 ◽  
pp. 17-17
Author(s):  
Jesús Casas ◽  
Josué Lagos
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Crystallization Process ◽  
Aqueous Ethanol ◽  
Sodium Molybdate ◽  
Operating Costs ◽  
Industrial Processes ◽  
Saturation Control ◽  
Crystallization Method ◽  
Evaporative Crystallization

The drowning-out crystallization process of sodium molybdate (Na2MoO4) was studied in water-ethanol solutions at room temperature. Sodium molybdate was separated from the solution in well crystalline particles using less water and energy compared with the industrial processes that use evaporative crystallization. Results showed that crystallization of sodium molybdate di-hydrate was achieved after 20 or 40 minutes, in one or two operating stages for super-saturation control with the addition of 25 or 50 vol% ethanol respectively. Crystallization with ethanol could reduce the operating costs in about 32%, respect to conventional evaporative crystallization method and the exhausted ethanol in the aqueous solution could be recovered by distillation and then recycled into the process.

scholarly journals Wetting controls of droplet formation in step emulsification

2018 ◽  
Vol 115 (38) ◽  
pp. 9479-9484 ◽  
Author(s):  
Maximilian L. Eggersdorfer ◽  
Hansjörg Seybold ◽  
Alessandro Ofner ◽  
David A. Weitz ◽  
André R. Studart
Keyword(s):  
Contact Angle ◽  
Droplet Size ◽  
High Speed ◽  
Droplet Formation ◽  
Industrial Processes ◽  
Wetting Properties ◽  
The Past ◽  
Minimal Contact ◽  
Wetting Process ◽  
Insight Into

The formation of droplets is ubiquitous in many natural and industrial processes and has reached an unprecedented level of control with the emergence of milli- and microfluidics. Although important insight into the mechanisms of droplet formation has been gained over the past decades, a sound understanding of the physics underlying this phenomenon and the effect of the fluid’s flow and wetting properties on the droplet size and production rate is still missing, especially for the widely applied method of step emulsification. In this work, we elucidate the physical controls of microdroplet formation in step emulsification by using the wetting of fluidic channels as a tunable parameter to explore a broad set of emulsification conditions. With the help of high-speed measurements, we unequivocally show that the final droplet pinch-off is triggered by a Rayleigh–Plateau-type instability. The droplet size, however, is not determined by the Rayleigh–Plateau breakup, but by the initial wetting regime, where the fluid’s contact angle plays a crucial role. We develop a physical theory for the wetting process, which closely describes our experimental measurements without invoking any free fit parameter. Our theory predicts the initiation of the Rayleigh–Plateau breakup and the transition from dripping to jetting as a function of the fluid’s contact angle. Additionally, the theory solves the conundrum why there is a minimal contact angle of α = 2π/3 = 120° for which droplets can form.

scholarly journals Fast and Accurate Thickness Mapping of Thin Liquid Films

2019 ◽  
Vol 215 ◽  
pp. 12002
Author(s):  
Zhe Wang ◽  
Vincenzo Ferraro ◽  
Biagio Mandracchia ◽  
Ernesto Di Maio ◽  
Pier Luca Maffettone ◽  
...  
Keyword(s):  
Thin Film ◽  
Life Science ◽  
Liquid Films ◽  
Thin Liquid Films ◽  
Industrial Processes ◽  
Phase Imaging ◽  
Protein Films ◽  
Quantitative Phase Imaging ◽  
Materials Engineering ◽  
Level Of Details

The thickness of thin liquid films is of great interest to industrial processes and life science. However, there are not appropriate quantitative experimental tools for an adequate study of film evolution in case of not-ideal conditions. Here, we show the application of a holographic system for the evaluation of the 3D topography and thickness of evolving protein films. We use a custom holographic microscope that combines quantitative phase imaging with materials engineering. This technique offers an unprecedented level of details and we anticipate that it will promote a deeper understanding of the underlying physics of thin film dynamics.

Limnological characteristics, community metabolism and management strategies of a coastal sinkhole in Cuba (Cenote Jennifer)

2020 ◽  
Vol 56 ◽  
pp. 24
Author(s):  
Roberto González-De Zayas ◽  
Liosban Lantigua Ponce de León ◽  
Liezel Guerra Rodríguez ◽  
Felipe Matos Pupo ◽  
Leslie Hernández-Fernández
Keyword(s):  
Hydrogen Sulfide ◽  
Primary Productivity ◽  
Major Ions ◽  
Saline Water ◽  
Management Strategies ◽  
Tourist Destination ◽  
Community Metabolism ◽  
Morphological Studies ◽  
Made In ◽  
Limnological Parameters

The Cenote Jennifer is an important and unique aquatic sinkhole in Cayo Coco (Jardines del Rey Tourist Destination) that has brackish to saline water. Two samplings were made in 1998 and 2009, and 4 metabolism community experiments in 2009. Some limnological parameters were measured in both samplings (temperature, salinity, pH, dissolved oxygen major ions, hydrogen sulfide, nutrients and others). Community metabolism was measured through incubated oxygen concentration in clear and dark oxygen bottles. Results showed that the sinkhole limnology depends on rainfall and light incidence year, with some stratification episodes, due to halocline or oxycline presence, rather than thermocline. The sinkhole water was oligotrophic (total nitrogen of 41.5 ± 22.2 μmol l−1 and total phosphorus of 0.3 ± 0.2 μmol l−1) and with low productivity (gross primary productivity of 63.0 mg C m−2 d−1). Anoxia and hypoxia were present at the bottom with higher levels of hydrogen sulfide, lower pH and restricted influence of the adjacent sea (2 km away). To protect the Cenote Jennifer, tourist exploitation should be avoided and more resources to ecological and morphological studies should be allocated, and eventually use this aquatic system only for specialized diving. For conservation purposes, illegal garbage disposal in the surrounding forest should end.

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