scholarly journals Endolithic phototrophs: Examples from cave-like environments

2021 ◽  
pp. 123-137
Author(s):  
Slađana Popović ◽  
Nataša Nikolić ◽  
Dragana Predojević ◽  
Olga Jakovljević ◽  
Tonči Rađa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Harsh Environments ◽  
Rock Matrix ◽  
Low Diversity ◽  
Rock Substratum ◽  
Geomorphological Features ◽  
Scanning Electron ◽  
Desirable Trait

Endoliths are more frequently found in extremely harsh environments, but they can inhabit mesic climate and subterranean habitats as well. Whether they are adapted to life inside rocks or do they seek refuge in this way, remains largely unknown for caves and pits. Consequently, subterranean habitats in limestone areas, were explored: three caves in Serbia (Cerjanska, Petnička and Potpeć) and one pit in Croatia (Keranova Golubinka). Sampling of rock substratum containing endoliths was performed at various distances from the entrance, at sites characterized by a lower level of light intensity. Phototrophs were separated from the rock matrix using 10% hydrochloric acid and analyzed using light microscopy. In general, low diversity of endoliths was observed, but representatives from Cyanobacteria, Chlorophyta and Xanthophyta were found. Cyanobacteria, more precisely coccoid forms (genera Aphanocapsa, Chroococcidiopsis, Gloeocapsa, Gloeocapsopsis, Synechococcus), were dominant. The most interesting cyanobacterial taxon, Leptolyngbya-like taxon, representing a true endolith (euendolith), was found in the Petnička Cave. This taxon and its relation to the substratum, as well as chasmoendolithic community from the Keranova Golubinka Pit, were observed using Scanning electron microscopy (SEM). It was observed that chasmoendoliths inhabit already existing surface rock cracks and fissures, while a true endolith actively bores into the substratum. Non-metric multidimensional scaling (NMDS) was performed to observe the similarity between the sampling sites. Endoliths can grow inside the rocks, making them very successful biodeteriogens, which is not a desirable trait for caves and pits that are characterized by various attractive geomorphological features that need to be preserved. Thus, considering these habitats, more attention should be paid to the endolith community in the future.

Surface Morphology and the Adsorptive Behavior of Coconut Active Carbon

2013 ◽  
Vol 690-693 ◽  
pp. 1029-1032
Author(s):  
Xiao Qiang Li ◽  
Li Juan Lan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Active Carbon ◽  
Adsorption Process ◽  
Hydrochloric Acid Concentration ◽  
Impregnation Method ◽  
Adsorption Experiment ◽  
Adsorptive Behavior ◽  
Scanning Electron

Active carbon modified by hydrochloric acid was prepared with impregnation method. The synthesized material was characterized by scanning electron microscopy. It was proved that plenty of pores with diameter of about 5-10μm were exist on the surface of active carbon. The adsorption process with toluene was performed over the modified active carbon to investigate the adsorptive efficiency. For comparison, other porous materials were also performed the adsorption experiment. The results showed that active carbon modified by hydrochloric acid has high adsorptive efficiency for toluene. The results proved that adsorptive performance of active carbon increased with the hydrochloric acid concentration.

scholarly journals Deposition of Gold (III) from Hydrochloric Acid Solutions on Carbon Nanotubes under Hydrothermal Conditions

2019 ◽  
pp. 494-502 ◽  
Author(s):  
Roman V. Borisov ◽  
Oleg V. Belousov ◽  
Anatoliy M. Zhizhaev
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Elevated Temperatures ◽  
Acid Solutions ◽  
Hydrothermal Conditions ◽  
Gold Particles ◽  
Hydrochloric Acid Solutions ◽  
Scanning Electron

The paper deals with the recovery of gold (III) from hydrochloric acid solutions on carbon based nanotube material at elevated temperatures under autoclave conditions. It is established that the quantitative recovery of gold (III) from hydrochloric acid solution upon its contact with carbon material occurs at a temperature of 170 °C for 240 minutes. The morphological features of metallic gold particles are studies by scanning electron microscopy

scholarly journals Copper corrosion inhibitors based on polyvinyl alcohol and silver nanoparticles

2019 ◽  
Vol 25 (3) ◽  
pp. 267-275 ◽  
Author(s):  
Roxana Grecu ◽  
Adriana Samide ◽  
Gabriela Iacobescu ◽  
Nicoleta Cioateră ◽  
Alexandru Popescu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silver Nanoparticles ◽  
Hydrochloric Acid ◽  
Polyvinyl Alcohol ◽  
Acid Solution ◽  
Corrosion Inhibitors ◽  
Copper Surface ◽  
Copper Corrosion ◽  
Scanning Electron

Polyvinyl alcohol (PVA) and silver nanoparticles/poly(vinyl) alcohol system (nAg/PVA) were investigated as copper corrosion inhibitors in hydrochloric acid solution by electrochemical measurements, such as potentiodynamic polarization and cyclic voltammetry associated with the atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) analysis. The potentiodynamic curves processed as a semilogarithmic diagram were employed for corrosion current density (icorr) computing that reached the highest value for copper corrosion in uninhibited hydrochloric acid solution and the lowest value in nAg/PVA inhibitor presence, resulting in a picked-up inhibition performance, greater than 95%. Recording ten cycles of CV, the initiation, development and stability of upper-layer formed on the copper surface in the presence of inhibitors was confirmed. It can be asserted that PVA acts by the adsorption of Cu(II)-PVA complexes or crosslinked PVA-copper aggregates and additionally, in the presence of nAg/PVA of some compounds involving silver attached to PVA. AFM 3D images showed completely different morphologies of the copper surface layers formed in the absence and presence of inhibitors. Just like AFM, a more regular and uniform arrangement of the surface layer, due to the silver interconnected to PVA macromolecular chain, was displayed by scanning electron microscopy (SEM) images.

scholarly journals Durability of Superamphiphobic Polyester Fabrics in Simulated Aerodynamic Icing Conditions

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1058
Author(s):  
Alexandre Laroche ◽  
Linda Ritzen ◽  
Javier Alejandro Mayén Guillén ◽  
Vittorio Vercillo ◽  
Maria D’Acunzi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Prolonged Exposure ◽  
Harsh Environments ◽  
Angle Measurements ◽  
Coated Fabrics ◽  
Liquid Repellency ◽  
Physical Changes ◽  
Scanning Electron

Fabrics treated to repel water, superhydrophobic, and water and oil, superamphiphobic, have numerous industrial and consumer-level benefits. However, the liquid repellency decreases in the course of time. This is largely due to chemical or physical changes of the coating due to prolonged exposure to relatively harsh environments. To develop more durable fabric treatments for specific applications, it is necessary to measure the extent to which the treated fabrics retain their low-wettability after being subjected to controlled aggressive environmental conditions. In this study, plain weave fabrics made from polyester filaments and coated with silicone nanofilaments in-solution were exposed to aerodynamic icing conditions. The coated fabrics showed superhydrophobic behavior, or superamphiphobic for those that were fluorinated. The wettability of the fabrics was progressively evaluated by contact angle and roll-off-angle measurements. The coated fabrics were able to maintain their low-wettability characteristics after exposure to water droplet clouds at airspeeds up to 120 m/s, despite damage to the silicone nanofilaments, visible through scanning electron microscopy.

scholarly journals Studies on the preparation of lead(II) chloride from galvanizing plant wastes

2013 ◽  
Vol 47 (4) ◽  
pp. 415-420 ◽  
Author(s):  
MM Rahman ◽  
AJMT Neger ◽  
A Gafur ◽  
ASW Kurny
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Diffraction Analysis ◽  
Atomic Absorption ◽  
Spectroscopic Analysis ◽  
Lead Chloride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Galvanizing plant wastes containing 71.82% lead was leached in hydrochloric acid. Lead was precipitated from the leach liquor as lead chloride and purified by recrystallisation. The process parameters like concentration of hydrochloric acid, time of leaching, mode of reaction, number of re-crystallization etc. were optimised. Nearly 70% of lead contained by the waste material could be leached out and converted to lead(II) chloride. The product (PbCl2) was characterised by atomic absorption spectroscopy, thermogravimetric analysis, x-ray diffraction analysis, and scanning electron microscopy. Atomic absorption spectroscopic analysis showed that the product was 93% pure. X-ray diffraction analysis confirmed that the product possess cotunnite phase having orthorhombic structure. The needle like shape of the prepared PbCl2 crystal was confirmed by scanning electron microscopy. Physical properties like melting point and density were also very close to those reported in literature. Bangladesh J. Sci. Ind. Res. 47(4), 415-420, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.14071

Study of Solvent Extraction of Mercury(II) with Dibenzo-18-Crown-6 from Hydrochloric Acid Solution into Benzene

1999 ◽  
Vol 23 (5) ◽  
pp. 299-299
Author(s):  
Rita Giovannetti ◽  
Vito Bartocci ◽  
Laura Petetta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solvent Extraction ◽  
Hydrochloric Acid ◽  
Acid Solution ◽  
Hydrochloric Acid Solution ◽  
Energy Dispersive ◽  
Chloro Complexes ◽  
X Ray ◽  
Scanning Electron

The effect of Li+, K+, NH+4, Ca2+ or Sr2+ in the extraction of mercury(II) as chloro-complexes from solutions in hydrochloric acid with dibenzo-18-crown-6 (DB18C6) into benzene and the stoichiometries of the reactions have been studied. The crystalline extracted species were characterized by morphological and microanalysis measurements by scanning electron microscopy and energy dispersive X-ray spectrometry respectively.

Preparation of Zeolite A from Natural Stellerite

2012 ◽  
Vol 624 ◽  
pp. 287-290
Author(s):  
Chun Ying Zhang ◽  
Nan Chun Chen ◽  
Xiao Hu Zhang ◽  
Quan Tang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Crystallization Time ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
End Products ◽  
Ft Ir ◽  
Scanning Electron

Zeolite A was prepared from natural stellerite under hydrothermal conditions.The experiments were carried at different crystallization temperatures and times，the experimental results and synthetical factors were analyzed and researched. The end products have been characterized by using FT–IR, X–ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that zeolite A was synthesized on the condition of the crystallization temperature at 90~100°C and the crystallization time for 6 hours with 15% hydrochloric acid of stellerite modifying，according to certain proportion of stellerite.

Chrysophycean stomatocysts from Xinjiang Province, China

Phytotaxa ◽  
2016 ◽  
Vol 288 (1) ◽  
pp. 41 ◽  
Author(s):  
WANTING PANG ◽  
QUANXI WANG
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Central Asia ◽  
Working Group ◽  
First Report ◽  
Low Diversity ◽  
Scanning Electron

Chrysophycean stomatocysts from 167 samples taken at 35 localities in Xinjiang Province, China were observed by scanning electron microscopy. The stomatocysts assemblages are characterized by low diversity and low abundance. Only 19 morphotypes were identified, of which nine are new to science. New stomatocysts were described following International Statospore Working Group (ISWG) guidelines. This is the first report of chrysophycean stomatocysts from Central Asia.

Preparation of Silicon Dioxide Fiber via Sol-Gel Process

2008 ◽  
Vol 368-372 ◽  
pp. 794-796
Author(s):  
Xiao Hui Wang ◽  
Xiao Ping Liang ◽  
Shao Bo Xin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrochloric Acid ◽  
Silicon Dioxide ◽  
Sol Gel ◽  
Tetraethyl Orthosilicate ◽  
Molar Ratio ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Scanning Electron

Silicon dioxide gel fibers were prepared by hydrolysis reaction of tetraethyl orthosilicate (TEOS). TEOS was used as basic materials, anhydrous ethanol (EtOH) as solvent and hydrochloric acid (HCl) as the catalyst. The best proportion of the chosen materials (TEOS, EtOH, H2O and HCl) was 1:1:1.5:0.03(molar ratio).Gel fibers were investigated by thermogravimetry (TG). Silicon dioxide fibers were obtained by treating the gel fibers at different temperatures. The calcined fibers were characterized by scanning electron microscopy (SEM). The optimal sintering schedule was obtained. Silicon dioxide fiber dried at 200°C for 1 hour then calcined at 800°C for 3 hours was the best.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

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