scholarly journals Dynamics and healing behavior of metallosupramolecular polymers

2021 ◽  
Vol 7 (18) ◽  
pp. eabe4154
Author(s):  
Laura N. Neumann ◽  
Emad Oveisi ◽  
Albrecht Petzold ◽  
Robert W. Style ◽  
Thomas Thurn-Albrecht ◽  
...  
Keyword(s):  
Contact Time ◽  
High Spatial Resolution ◽  
Glassy Polymers ◽  
Self Healing ◽  
Physical Damage ◽  
X Ray ◽  
Diffusion Depth ◽  
Spectrum Imaging ◽  
Materials Used ◽  
Mechanical Recovery

Self-healing or healable polymers can recuperate their function after physical damage. This process involves diffusion of macromolecules across severed interfaces until the structure of the interphase matches that of the pristine material. However, monitoring this nanoscale process and relating it to the mechanical recovery remain elusive. We report that studying diffusion across healed interfaces and a correlation of contact time, diffusion depth, and mechanical properties is possible when two metallosupramolecular polymers assembled with different lanthanoid salts are mended. The materials used display similar properties, while the metal ions can be tracked with high spatial resolution by energy-dispersive x-ray spectrum imaging. We find that healing actual defects requires an interphase thickness in excess of 100 nm, 10 times more than previously established for self-adhesion of smooth films of glassy polymers.

scholarly journals The Archaeometallurgical Evaluation of Three Bronze Socketed Axes, Discovered in Eastern Romania

2021 ◽  
Vol 11 (4) ◽  
pp. 1811
Author(s):  
Viorica Vasilache ◽  
Vasile Diaconu ◽  
Otilia Mircea ◽  
Ana Drob ◽  
Ion Sandu
Keyword(s):  
Electron Microscopy ◽  
Optical Microscopy ◽  
Corrosion Layer ◽  
Surface Structures ◽  
Manufacturing Processes ◽  
Metal Core ◽  
Physical Damage ◽  
Chemical Alteration ◽  
X Ray ◽  
Materials Used

This paper presents the study of three bronze socketed axes discovered in Neamţ County, Romania. The surface structures and those from the interface of the corrosion layer with the metal core of the basic alloy were analyzed, in order to elucidate the nature of the materials used and the manufacturing processes. The analyzes by optical microscopy (OM) and electron microscopy (SEM), coupled with X-ray spectrometry (EDX), revealed the type of their degradation during the depositional period, as a result of the processes of chemical alteration and physical damage. A series of metallurgical techniques used were also established, as well as the identification of some finishing and decoration processes that led to the establishment of the objects’ functionality.

High Spatial Resolution Compositional Analysis at Interfaces

1980 ◽  
Vol 38 ◽  
pp. 356-359
Author(s):  
John B. Vander Sande ◽  
Thomas F. Kelly ◽  
Douglas Imeson
Keyword(s):  
Electron Microscope ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Thin Specimen ◽  
X Ray ◽  
Volume Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the scanning transmission electron microscope (STEM) a fine probe of electrons is scanned across the thin specimen, or the probe is stationarily placed on a volume of interest, and various products of the electron-specimen interaction are then collected and used for image formation or microanalysis. The microanalysis modes usually employed in STEM include, but are not restricted to, energy dispersive X-ray analysis, electron energy loss spectroscopy, and microdiffraction.

scholarly journals Release of toxic methylene blue from water by mesoporous silicalite-1: characterization, kinetics and isotherm studies

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Sabarish Radoor ◽  
Jasila Karayil ◽  
Aswathy Jayakumar ◽  
Jyotishkumar Parameswaranpillai ◽  
Suchart Siengchin
Keyword(s):  
Electron Microscopy ◽  
Contact Time ◽  
Dye Removal ◽  
Batch Adsorption ◽  
Aqueous Environment ◽  
Order Kinetic ◽  
Adsorption Method ◽  
X Ray ◽  
Ft Ir ◽  
Adsorption Desorption

AbstractIn the present work, we have developed a mesoporous silicalite-1 using CMC as a template for the removal of MB from aqueous solution. The synthesized silicalite-1 were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Energy-dispersive X-ray spectroscopy (EDAX) and N2 adsorption–desorption isotherm (BET). XRD and FT-IR analysis confirmed the formation of crystallinity and development of MFI structure in the mesoporous silicalite-1. The adsorption of MB dye on mesoporous silicalite-1 was conducted by batch adsorption method. The effect of various parameters such as adsorbent dosage, initial dye concentration, contact time and temperature on the dye uptake ability of silicalite-1 was investigated. The operating parameters for the maximum adsorption are silicalite-1 dosage (0.1 wt%), contact time (240 min), initial dye concentration (10 ppm) and temperature (30 ℃). The MB dye removal onto mesoporous silicalite-1 followed pseudo-second-order kinetic and Freundlich isotherm. The silicalite-1 exhibits 86% removal efficiency even after six adsorption–desorption cycle. Therefore, the developed mesoporous silicalite-1 is an effective eco-friendly adsorbent for MB dye removal from aqueous environment.

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

scholarly journals High-Spatial-Resolution Bone Densitometry with Dual-Energy X-ray Absorptiometric Region-free Analysis

Radiology ◽  
2015 ◽  
Vol 275 (1) ◽  
pp. 310-310 ◽  
Author(s):  
Richard M. Morris ◽  
Lang Yang ◽  
Miguel A. Martín-Fernández ◽  
Jose M. Pozo ◽  
Alejandro F. Frangi ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Bone Densitometry ◽  
High Spatial Resolution ◽  
Dual Energy ◽  
X Ray

Use of X-ray computed tomography for studying the desiccation cracking and self-healing of fine soil during drying–wetting paths

2021 ◽  
pp. 106255
Author(s):  
Mohammed Zaidi ◽  
Nasre-Dine Ahfir ◽  
Abdellah Alem ◽  
Said Taibi ◽  
Bouabid El Mansouri ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Self Healing ◽  
X Ray ◽  
Fine Soil ◽  
Desiccation Cracking ◽  
X Ray Computed

Small-angle x-ray scattering studies of crazed glassy polymers

1983 ◽  
Vol 21 (6) ◽  
pp. 969-982 ◽  
Author(s):  
Paul A. Westbrook ◽  
John F. Fellers ◽  
Robert W. Hendricks ◽  
J. S. Lin
Keyword(s):  
Small Angle ◽  
Glassy Polymers ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Enhancing removal efficiency of anionic dye (Cibacron blue) using waste potato peels powder

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kahina Bouhadjra ◽  
Wahiba Lemlikchi ◽  
Azedine Ferhati ◽  
Samuel Mignard
Keyword(s):  
Experimental Data ◽  
Contact Time ◽  
Potato Peel ◽  
X Ray ◽  
Cibacron Blue ◽  
Anionic Dye ◽  
Experimental Parameters ◽  
Optimum Ph ◽  
Potato Peels ◽  
Scanning Electron

AbstractIn the present study, the potato peel waste (PP) was used for the removal of the anionic dye Cibacron Blue P3R from an aqueous solution, activated with phosphoric acid (PPa) and calcined at 800 °C (PPc). The materials were characterized by Scanning Electron Microscope, Energy dispersive X-ray analysis and Fourier Transform Infrared Spectroscopy. The effects of various experimental parameters (pH, dye concentration, contact time) were also studied. The experimental results have shown that PPc has a greater capacity compared to pp and ppa. The capacity of PP bio-char (PPc) is 270.3 mg g−1 compared to PP (100 mg g−1) and PPa (125 mg g−1). Equilibrium experiments at 180 min for all materials were carried out at optimum pH (2.2): 76.41, 88.6 and 94% for PP, PPa and PPc respectively; and the Langmuir models agreed very well with experimental data. The ability of sorbent for the sorption of CB dye follows this order: calcined > activated > native materials. Potato peel biochar (PPc) can be considered a promising adsorbent for removing persistent dyes from water.

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