scholarly journals RESEARCH OF EFFICIENCY OF NANOSIZED POWDERED ICE-FORMING REAGENTS

2020 ◽  
pp. 31-40
Author(s):  
N.S. Kim ◽  
V.P. Korneev ◽  
A.M. Petrunin ◽  
A.V. Chastuhin ◽  
E.F. Voronin
Keyword(s):  
High Activity ◽  
Silver Iodide ◽  
High Surface ◽  
High Mountain ◽  
Laboratory Studies ◽  
Geophysical Institute ◽  
Low Efficiency ◽  
Nanosilica Particles ◽  
Central Aerological Observatory ◽  
High Surface Activity

The article discusses nanosized powdery ice-forming reagents, which are supposed to be used in the works on active action on clouds in order to regulate precipitation and hail suppression, as well as to dissipate supercooled fog. These ice-forming reagents have been obtained by the levilite method, in which a layer of silver iodide is deposited on the surface of nanosilica particles. Description of the methodology for studying the effectiveness of nanosized powdery ice-forming reagents, as well as the results of laboratory studies of their effectiveness obtained in different organizations is given. The results of studies of ice-forming reagents carried out at laboratories of RPA “Typhoon”, High-Mountain Geophysical Institute, JSC “Cheboksary production association n.a. V.I. Chapaev” and ANO “Agency of atmospheric technologies” have shown that the efficiency of these reagents differs significantly from those obtained earlier in the Central Aerological Observatory. It has been suggested that the low efficiency of nanosized ice-forming reagents is due to the high aggregation of the original nanosilicum particles, resulting from the high surface activity of these particles. Possible ways to reduce the degree of aggregation of powders by modifying the surface of the original nanoparticles aimed at decreasing the high activity of the nanosilica particles surface are discussed.

scholarly journals Use of depressants in the direct flotation of a silicate-carbonate phosphate ore

2014 ◽  
Vol 67 (2) ◽  
pp. 191-196
Author(s):  
Adalberto Leles de Souza ◽  
Rodrigo Oscar de Albuquerque ◽  
Fernando Soares Lameiras ◽  
Plínio Eduardo Praes ◽  
Antônio Eduardo Clark Peres
Keyword(s):  
High Surface ◽  
Mining Industry ◽  
Mineral Resources ◽  
Ionic Species ◽  
Separation Processes ◽  
Phosphate Ore ◽  
Superficial Similarity ◽  
Low Efficiency ◽  
Silicate Carbonate ◽  
High Surface Activity

A high demand for mineral resources observed in recent decades has led to an expansion in production in the mining industry. Different process alternatives have been proposed for selective separation between apatite and contaminants (carbonates and silicates) present in phosphate ores. Magnetic separation, calcination and gravity separation processes are methods that present low efficiency and high cost. Flotation is the most common process; however the selectivity is hampered by the superficial similarity of the chemical composition of phosphates and carbonates, high surface activity of the collectors used, interactions between dissolved ionic species of certain mineral with another and also interactions between dissolved ionic species and reagents. In this study, conducted in a laboratory scale, eight different depressants, organic and inorganic, were tested in the direct flotation of a Brazilian silicate-carbonate phosphate ore. The best performance in the depression of calcite and silicates was achieved with cassava starch.

scholarly journals Effects of Annealing Temperature on the Oxygen Evolution Reaction Activity of Copper–Cobalt Oxide Nanosheets

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 657
Author(s):  
Geul Han Kim ◽  
Yoo Sei Park ◽  
Juchan Yang ◽  
Myeong Je Jang ◽  
Jaehoon Jeong ◽  
...  
Keyword(s):  
High Activity ◽  
Cobalt Oxide ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Cobalt Hydroxide ◽  
Ni Foam ◽  
Electron Conduction

Developing high performance, highly stable, and low-cost electrodes for the oxygen evolution reaction (OER) is challenging in water electrolysis technology. However, Ir- and Ru-based OER catalysts with high OER efficiency are difficult to commercialize as precious metal-based catalysts. Therefore, the study of OER catalysts, which are replaced by non-precious metals and have high activity and stability, are necessary. In this study, a copper–cobalt oxide nanosheet (CCO) electrode was synthesized by the electrodeposition of copper–cobalt hydroxide (CCOH) on Ni foam followed by annealing. The CCOH was annealed at various temperatures, and the structure changed to that of CCO at temperatures above 250 °C. In addition, it was observed that the nanosheets agglomerated when annealed at 300 °C. The CCO electrode annealed at 250 °C had a high surface area and efficient electron conduction pathways as a result of the direct growth on the Ni foam. Thus, the prepared CCO electrode exhibited enhanced OER activity (1.6 V at 261 mA/cm2) compared to those of CCOH (1.6 V at 144 mA/cm2), Co3O4 (1.6 V at 39 mA/cm2), and commercial IrO2 (1.6 V at 14 mA/cm2) electrodes. The optimized catalyst also showed high activity and stability under high pH conditions, demonstrating its potential as a low cost, highly efficient OER electrode material.

Production and Properties of Biosurfactants from a Newly Isolated Pseudomonas fluorescens HW-6 Growing on Hexadecane

2006 ◽  
Vol 61 (7-8) ◽  
pp. 553-559 ◽  
Author(s):  
Evgenia Vasileva-Tonkova ◽  
Danka Galabova ◽  
Emilia Stoimenova ◽  
Zdravko Lalchev
Keyword(s):  
Pseudomonas Fluorescens ◽  
Industrial Wastewater ◽  
High Surface ◽  
Emulsifying Properties ◽  
Effective Surface ◽  
Mineral Oils ◽  
Air Water Interface ◽  
Polluted Sites ◽  
High Concentrations ◽  
High Surface Activity

The newly isolated from industrial wastewater Pseudomonas fluorescens strain HW-6 produced glycolipid biosurfactants at high concentrations (1.4-2.0 g l-1) when grown on hexadecane as a sole carbon source. Biosurfactants decreased the surface tension of the air/ water interface by 35 mN m-1 and possessed a low critical micelle concentration value of 20 mg l-1, which indicated high surface activity. They efficiently emulsified aromatic hydrocarbons, kerosene, n-paraffins and mineral oils. Biosurfactant production contributed to a significant increase in cell hydrophobicity correlated with an increased growth of the strain on hexadecane. The results suggested that the newly isolated strain of Ps. fluorescens and produced glycolipid biosurfactants with effective surface and emulsifying properties are very promising and could find application for bioremediation of hydrocarbon-polluted sites.

scholarly journals Atmospheric β-Caryophyllene-Derived Ozonolysis Products at Interfaces

2018 ◽  
Author(s):  
Ariana Gray Bé ◽  
Hilary M. Chase ◽  
Liu, Yangdongliu ◽  
Mary Alice Upshur ◽  
Zhang, Yue ◽  
...  
Keyword(s):  
Gas Phase ◽  
Structural Information ◽  
High Surface ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Laboratory Studies ◽  
Sum Frequency ◽  
Sum Frequency Generation Spectroscopy ◽  
Surface Active ◽  
Cloud Activation

<p>By integrating organic synthesis, secondary organic aerosol synthesis and collection, DFT calculations, and vibrational sum frequency generation spectroscopy, we identify close spectral matches between the surface vibrational spectra of β-caryophyllene-derived secondary organic material and those of β-caryophyllene aldehyde and β-caryophyllonic acid at various interfaces. Combined with the record high surface tension depression described previously for these same oxidation products, we discuss possibilities for an intrinsically chemical origin for cloud activation by terpene-derived surfactants. Although the present study does not unequivocally identify the synthesized and analyzed oxidation products on the β-caryophyllenederived SOM surfaces, these two compounds appear to be the most surface active out of the series, and have also been foci of previous β-caryophyllene field and laboratory studies.</p><p>An orientation analysis by phase-resolved SFG spectroscopy reveals a “pincer-like” configuration of the β-caryophyllene oxidation products, albeit on a model quartz surface, that somewhat resembles the orientation of inverse double-tailed surfactants at the surfaces biological systems. The structural information suggests that the less polar moiety of a surface-localized oxidation product, such as those studied here, may be the first site-of-contact for a gas-phase molecule approaching an SOA particle containing surface-active β-caryophyllene oxidation products.</p>

scholarly journals Coordination modulation of iridium single-atom catalyst maximizing water oxidation activity

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhanwu Lei ◽  
Wenbin Cai ◽  
Yifei Rao ◽  
Kuan Wang ◽  
Yuyuan Jiang ◽  
...  
Keyword(s):  
High Activity ◽  
Current Density ◽  
Water Oxidation ◽  
Distribution Density ◽  
High Surface ◽  
Single Atom ◽  
Surface Distribution ◽  
Oxidation Activity ◽  
Nanosheet Arrays ◽  
A Current

AbstractSingle-atom catalysts (SACs) have attracted tremendous research interests in various energy-related fields because of their high activity, selectivity and 100% atom utilization. However, it is still a challenge to enhance the intrinsic and specific activity of SACs. Herein, we present an approach to fabricate a high surface distribution density of iridium (Ir) SAC on nickel-iron sulfide nanosheet arrays substrate (Ir1/NFS), which delivers a high water oxidation activity. The Ir1/NFS catalyst offers a low overpotential of ~170 mV at a current density of 10 mA cm−2 and a high turnover frequency of 9.85 s−1 at an overpotential of 300 mV in 1.0 M KOH solution. At the same time, the Ir1/NFS catalyst exhibits a high stability performance, reaching a lifespan up to 350 hours at a current density of 100 mA cm−2. First-principles calculations reveal that the electronic structures of Ir atoms are significantly regulated by the sulfide substrate, endowing an energetically favorable reaction pathway. This work represents a promising strategy to fabricate high surface distribution density single-atom catalysts with high activity and durability for electrochemical water splitting.

scholarly journals VIII ALL-RUSSIAN CONFERENCE ON ATMOSPHERIC ELECTRICITY

2019 ◽  
pp. 11-18
Author(s):  
П.П. Фирстов ◽  
В.И. Козлов ◽  
Е.И. Малкин
Keyword(s):  
Atmospheric Electricity ◽  
High Mountain ◽  
Geophysical Institute ◽  
Russian Academy Of Sciences ◽  
Academy Of Sciences ◽  
Russian Conference

С 23 по 27 сентября 2019 г. в г. Нальчик состоялась VIII Всероссийская конференция по атмосферному электричеству. Конференция была организована Российской академией наук, Военно-космической академией имени А.Ф. Можайского (ВКА им. А.Ф. Можайского) и Высокогорным геофизическим институтом Росгидромета (ВГИ). В данной статье описана работа конференции и приведены некоторые положения из решения конференции. From September 23 to September 27, 2019, the VIII All-Russian Conference on Atmospheric Electricity was held in Nalchik. The conference was organized by the Russian Academy of Sciences, the A.F. Mozhaisk (All-Russian Academy of Sciences named after AF Mozhaisk) and the High Mountain Geophysical Institute of Roshydromet (VGI). This article describes the work of the conference and some of the provisions of the conference decision.

scholarly journals A novel biosensor based on Blu-ray disc coating film for determination of total amino acid content in tea leaves

RSC Advances ◽  
2021 ◽  
Vol 11 (63) ◽  
pp. 39666-39671
Author(s):  
Lanling Chu ◽  
Yunzheng Wang ◽  
Yu Zhou ◽  
Xuejun Kang
Keyword(s):  
Low Cost ◽  
High Surface ◽  
Amino Acid Content ◽  
Substrate Material ◽  
Total Amino Acid ◽  
Coating Film ◽  
The Novel ◽  
Total Amino Acid Content ◽  
High Surface Activity

The novel biosensor substrate material based on a simple BD coating film displayed preferable merits with high surface activity, low cost, easy making, easy using, and extensive application prospect.

The Effect of Nanosilica on the Early Strength of Alkali-Activated Portland Composite Cements

2019 ◽  
Vol 296 ◽  
pp. 21-26 ◽  
Author(s):  
Pavel V. Krivenko ◽  
Myroslav Sanytsky ◽  
Tetiana Kropyvnytska
Keyword(s):  
High Surface ◽  
Strength Properties ◽  
Surface Reactivity ◽  
Strength Development ◽  
Early Age ◽  
Composite Cement ◽  
Granulated Blast Furnace Slag ◽  
Natural Pozzolana ◽  
Nanosilica Particles ◽  
Composite Cements

Significant reduction of carbon footprint of the construction industry is achieved through the use of composite Portland cements. However, substitution levels of additives in the composite cements are limited due to slow strength development arising from low reactivity of the pozzolana compared to clinker phases especially at the early age. The aim of the study was to evaluate effect of nanosilica on formation of strength properties and structure at the early age. The Portland composite cement containing clinker, granulated blast furnace slag, zeolite tuff as natural pozzolana and limestone with additives of nanosilica, Na2SO4 and polycarboxylate ether was investigated. The results obtained with the help of PSD, XRD, DTA, TG and SEM techniques showed that addition into the cement paste of the nanosilica particles with high surface reactivity improved the composite cement microstructure and leaching of calcium became significantly lower, because nanosilica particles react with calcium hydroxide with the formation of a denser C-S-H gel at the early age of hardening.

scholarly journals Mesoporous Nanocast Electrocatalysts for Oxygen Reduction and Oxygen Evolution Reactions

Inorganics ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 98 ◽  
Author(s):  
Tatiana Priamushko ◽  
Rémy Guillet-Nicolas ◽  
Freddy Kleitz
Keyword(s):  
Oxygen Reduction ◽  
High Activity ◽  
Oxygen Evolution ◽  
Noble Metal ◽  
Noble Metals ◽  
Low Cost ◽  
High Surface ◽  
Clean Energy ◽  
Production Costs ◽  
Synthesis Methods

Catalyzed oxygen evolution and oxygen reduction reactions (OER and ORR, respectively) are of particular significance in many energy conversion and storage processes. During the last decade, they emerged as potential routes to sustain the ever-growing needs of the future clean energy market. Unfortunately, the state-of-the-art OER and ORR electrocatalysts, which are based on noble metals, are noticeably limited by a generally high activity towards one type of reaction only, high costs and relatively low abundance. Therefore, the development of (bi)functional low-cost non-noble metal or metal-free electrocatalysts is expected to increase the practical energy density and drastically reduce the production costs. Owing to their pore properties and high surface areas, mesoporous materials show high activity towards electrochemical reactions. Among all synthesis methods available for the synthesis of non-noble mesoporous metal oxides, the hard-templating (or nanocasting) approach is one of the most attractive in terms of achieving variable morphology and porosity of the materials. In this review, we thus focus on the recent advances in the design, synthesis, characterization and efficiency of non-noble metal OER and ORR electrocatalysts obtained via the nanocasting route. Critical aspects of these materials and perspectives for future developments are also discussed.

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