scholarly journals Electroactive Hydrogels Made with Polyvinyl Alcohol/Cellulose Nanocrystals

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1615 ◽  
Author(s):  
Tippabattini Jayaramudu ◽  
Hyun-U Ko ◽  
Hyun Kim ◽  
Jung Kim ◽  
Ruth Muthoka ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Active Drug ◽  
X Ray Diffraction ◽  
Uptake Capacity ◽  
X Ray ◽  
Freeze Thaw ◽  
Actuation Mechanism ◽  
Water Uptake Capacity ◽  
Electrostatic Effect ◽  
Scanning Electron

This paper reports a nontoxic, soft and electroactive hydrogel made with polyvinyl alcohol (PVA) and cellulose nanocrystal (CNC). The CNC incorporating PVA-CNC hydrogels were prepared using a freeze–thaw technique with different CNC concentrations. Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy results proved the good miscibility of CNCs with PVA. The optical transparency, water uptake capacity and mechanical properties of the prepared hydrogels were investigated in this study. The CNC incorporating PVA-CNC hydrogels showed improved displacement output in the presence of an electric field and the displacement increased with an increase in the CNC concentration. The possible actuation mechanism was an electrostatic effect and the displacement improvement of the hydrogel associated with its enhanced dielectric properties and softness. Since the prepared PVA-CNC hydrogel is nontoxic and electroactive, it can be used for biomimetic soft robots, actively reconfigurable lenses and active drug-release applications.

Preparation and Properties of Sintering Brick from Iron Tailings

2012 ◽  
Vol 512-515 ◽  
pp. 1023-1027
Author(s):  
Ran Fang Zuo ◽  
Gao Xiang Du ◽  
Le Fu Mei ◽  
Wei Juan Guo ◽  
Jing Hui Liao
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Bulk Density ◽  
Raw Materials ◽  
Loss On Ignition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw ◽  
Scanning Electron

The main objective of this paper was to investigate the addition of iron tailing sintering brick production, in the presence of clay, coal refuses and bentonite. Mixtures containing raw materials of sintering brick and iron tailings were prepared at different proportions (up to 55 wt %), fired at 980°C. Freeze/thaw durability, drying and firing shrinkages were investigated as well as the loss on ignition, bulk density and compressive strength of the fired samples. Their mechanical and microstructure properties were also investigated by differential thermal analysis (DTA/TG), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that compressive strengths of the brick samples are higher than that required by the standards MU15 of GB5101-2003, up to 21.79Mpa with 40% iron tailings corresponding to its higher bulk density completely. Moreover, the results showed that it has such advantages as no lime blowing, uniform color, good freeze/thaw resistance and slight universal frost.

Spray dried hydroxyapatite-polyvinyl alcohol biocomposites

2016 ◽  
Vol 36 (8) ◽  
pp. 795-804 ◽  
Author(s):  
Tuğba Başargan ◽  
Nalan Erdöl-Aydın ◽  
Gülhayat Nasün-Saygılı
Keyword(s):  
Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
Spray Dryer ◽  
Drying Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pva Solutions ◽  
Spray Dried ◽  
Scanning Electron

Abstract In this study, hydroxyapatite/polyvinyl alcohol (HAp-PVA) biocomposites were prepared using a spray drying method. HAp-PVA solutions fed to spray dryer were prepared by two different routes, namely, physical and in situ biomimetric methods. In the former method, HAp was synthesized without the presence of polymer and then HAp particles were incorporated into a PVA solution. In the second one, hydroxyapatite was in situ synthesized in the presence of PVA. Experiments were also run to investigate the effect of the molecular weight of PVA on the structure of spray-dried biocomposites. Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and particle size analyses were performed to characterize the produced HAp-PVA composites.

Experiment Study on the Effect of GGBFS on Frost Resistance of Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 207-212 ◽  
Author(s):  
Shi Yi Zhang ◽  
Ying Fang Fan ◽  
Qi Wang
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Plain Concrete ◽  
Industrial Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Scanning Electron

High volume utilization of industrial wastes and by products is the solution for high disposal coast. The anti-frost of high performance concrete is a key factor for safe utilization of concrete structure containing industrial wastes under severe environment. In this paper, to understand the property on anti-frost of high performance containing ground granulated blast furnace slag (GGBFS) under cold marine environment. Some comparison studies were conducted on plain concrete by rapid freeze-thaw cycle test. During the rapid freeze-thaw cycle test, the mass loss and relative elastic modulus were measured regularly at the prescribed conditioning ages. The development of microstructure in concrete was analyzed through scanning electron microscopy (SEM) and X-ray diffraction (XRD). The rapid freeze-thaw cycle test results show that the plain concrete was destroyed severely at 150 freeze-thaw cycles. After 225 freeze-thaw cycles, the mass loss and the relative dynamic modulus of elasticity of GGBFS concrete decrease 1.3% and 26.11%, respectively, that indicates that GGBFS significantly improve the anti-frost performance of concrete; The addition of GGBFS can accelerate the cement hydration reaction, promote more Ca (OH)2 crystals shift to C-S-H gel and help to increase the density of the micro-structure of concrete, which can prevent the formation of micro-cracks and suppress the propagation of cracks and thus effectively improve the durability of concrete. KEY WORDS: GGBFS; freeze-thaw durability; microstructure; scanning electron microscopy; X-ray diffraction.

scholarly journals The Zr-Doped CaO CO2 Sorbent Fabricated by Wet High-Energy Milling

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4110
Author(s):  
Vyacheslav V. Rodaev ◽  
Svetlana S. Razlivalova
Keyword(s):  
Zirconium Dioxide ◽  
High Energy ◽  
Co2 Uptake ◽  
Fabrication Technique ◽  
X Ray Diffraction ◽  
Uptake Capacity ◽  
X Ray ◽  
Co2 Sorbent ◽  
First Time ◽  
Scanning Electron

We fabricated the Zr-doped CaO sorbent for high-temperature CO2 capture by the wet high-energy co-milling of calcium carbonate and natural zirconium dioxide (baddeleyite) for the first time. The morphology of the material was examined by scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. Its CO2 uptake capacity was determined using thermogravimetric analysis. After 50 carbonation–calcination cycles, the Zr-doped CaO sorbent characterized by a high enough CO2 uptake capacity of 8.6 mmol/g and unchanged microstructure due to CaZrO3 nanoparticles uniformly distributed in the CaO matrix to prevent CaCO3 sintering under carbonation. The proposed easy-to-implement CaO-based sorbents fabrication technique is promising for industrial application.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

Sign in / Sign up

Export Citation Format

Share Document