Shape Stabilized Bio-Based PCMs Formed by Coaxial Electrospinning Technique

2012 ◽  
Author(s):  
Wen Hu ◽  
Xun Yu
Keyword(s):  
Electron Microscopy ◽  
Phase Change Materials ◽  
Environmental Scanning Electron Microscopy ◽  
Tensile Tests ◽  
Coaxial Electrospinning ◽  
Environmental Scanning ◽  
Fiber Morphology ◽  
Electrospinning Technique ◽  
Good Thermal Stability ◽  
Transmission Electron

Shape stabilized phase change materials was successfully prepared by encapsulating natural soy wax into polyurethane nanofibers. Coaxial electrospinning technique was used in this study. The morphology of the composites were characterized through environmental scanning electron microscopy (ESEM), Transmission electron microscopy (TEM), the thermal behaviors of the composites were also investigated. The results indicated that coaxial electrospinning resulted in a uniform fiber morphology with a core-shell structure, and a homogeneous wax distribution throughout the core of the fibers. Thermal analysis results show that the enthalpy increase with wax content. The fibrous structures exhibited balanced thermal storage and releasing properties for thermo-regulating function. The thermal properties were unaltered after 100 heating-cooling cycles tests, demonstrating that the composite fibers had good thermal stability and reliability. Tensile tests also indicate that the presence of wax enhanced the modulus and lowered the tensile strain.

scholarly journals Multifunctional Epoxy/Nanocomposites Based on Natural Moroccan Clays with High Antimicrobial Activity: Morphological, Thermal and Mechanical Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
M. Monsif ◽  
A. Zerouale ◽  
N. Idrissi Kandri ◽  
R. Bertani ◽  
A. Bartolozzi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antimicrobial Activity ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Clay Nanocomposites ◽  
Mechanical And Thermal Properties ◽  
Clay Dispersion ◽  
Mechanical Stirring ◽  
Antimicrobial Materials ◽  
Transmission Electron

In this study, a series of new epoxy/clay nanocomposites (ECN) has been prepared and characterized in order to investigate the properties and compare the effect of the unmodified Moroccan clay on the structure and properties of the composite materials. Five natural clays have been used to reinforce the neat epoxy resin with 1% wt and 5% wt achieving the clay dispersion only through strong milling and mechanical stirring without previous organic modifications of the clays. The quality of clay dispersion in the epoxy matrix and the morphology of nanocomposites have been studied by transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), and X-ray diffraction (XRD). The mechanical and thermal properties have also been investigated. The antimicrobial activity of the nanocomposites has been tested against E. coli and S. aureus in order to evaluate their applicability as advanced antimicrobial materials. The results showed that the epoxy/crude clay nanocomposites exhibited a high inhibition action attending 99% against both bacteria in the case of the clay labeled A5.

Characterization of Multilayer Thin Film Structures for Gas Sensor Applications

1995 ◽  
Vol 382 ◽  
Author(s):  
M. Dibattista ◽  
S. V. Patel ◽  
K. D. Wise ◽  
J. L. Gland ◽  
J. F. Mansfield ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensor ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Sensing Properties ◽  
Force Microscopy ◽  
Sensor Applications ◽  
Transmission Electron ◽  
Silicon Based ◽  
And Control

ABSTRACTA nicrofabricated silicon-based chemical gas sensor with a discontinuous film of Pt / TiOx, as the active sensing component has been characterized by atomic force microscopy, environmental scanning electron microscopy, and transmission electron microscopy. A study of the device's multilayer structure and of the thin sensing film is undertaken to understand and control the sensing properties of the metal / semiconducting materials. The purpose of this research is to advance the understanding of the conduction mechanism and provide a basis for optimizing the sensing properties and microstructure of the sensing device.

Effect of solids retention time on floc structure

2002 ◽  
Vol 46 (1-2) ◽  
pp. 431-438 ◽  
Author(s):  
S.N. Liss ◽  
B.Q. Liao ◽  
I.G. Droppo ◽  
D.G. Allen ◽  
G.G. Leppard
Keyword(s):  
Electron Microscopy ◽  
Retention Time ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Compact Structure ◽  
Sludge Flocs ◽  
Floc Structure ◽  
Transmission Electron ◽  
Solids Retention Time ◽  
Solids Retention

Correlative microscopy was applied to study the influence of solids retention time on activated sludge floc structure. Conventional optical microscopy revealed flocs at lower SRTs (4 and 9 days) to be irregular in shape while flocs at higher SRTs (16 and 20 days) had a more spherical and compact structure. Flocs were examined by environmental scanning electron microscopy (ESEM) and by transmission electron microscopy (TEM) coupled with energy-dispersive spectroscopy (EDS). Distinctive differences in floc structure and the arrangement of EPS were revealed. Flocs from higher SRTs were less hydrated and were found to possess a dense EPS layer that covers much of the surface. Extracellular osmiophilic granules present in these flocs indicate that the cells at the higher SRT may produce more lipid-like material. This EPS layer appears to decrease the floc surface roughness and protects the interior cells from disruption by changes in the external environment. Sludge flocs at higher SRTs were found to be physically more stable than those at lower SRTs.

scholarly journals Wet-STEM Tomography: Principles, Potentialities and Limitations

2014 ◽  
Vol 20 (2) ◽  
pp. 366-375 ◽  
Author(s):  
Karine Masenelli-Varlot ◽  
Annie Malchère ◽  
José Ferreira ◽  
Hamed Heidari Mezerji ◽  
Sara Bals ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Three Dimensional ◽  
Environmental Scanning Electron Microscopy ◽  
Inorganic Materials ◽  
Dimensional Structure ◽  
Environmental Scanning ◽  
Minimum Thickness ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Specific Device

AbstractThe characterization of biological and inorganic materials by determining their three-dimensional structure in conditions closer to their native state is a major challenge of technological research. Environmental scanning electron microscopy (ESEM) provides access to the observation of hydrated samples in water environments. Here, we present a specific device for ESEM in the scanning transmission electron microscopy mode, allowing the acquisition of tilt-series suitable for tomographic reconstructions. The resolution which can be obtained with this device is first determined. Then, we demonstrate the feasibility of tomography on wet materials. The example studied here is hydrophilic mesoporous silica (MCM-41). Finally, the minimum thickness of water which can be detected is calculated from Monte Carlo simulations and compared with the resolution expected in the tomograms.

Thermo-Reversible Protein Fibrillar Hydrogels

2006 ◽  
Vol 953 ◽  
Author(s):  
Aline Miller ◽  
Alberto Saiani ◽  
Hui Yan
Keyword(s):  
Electron Microscopy ◽  
Protein Denaturation ◽  
Pure Water ◽  
Environmental Scanning Electron Microscopy ◽  
Low Ph ◽  
Environmental Scanning ◽  
Egg White Lysozyme ◽  
Transmission Electron ◽  
Alkaline Conditions ◽  
Physical And Chemical

ABSTRACTHen egg white lysozyme (HEWL) was exposed to various physical and chemical denaturing environments to encourage protein denaturation and consequent gelation. Its phase behavior was examined as a function of pH, temperature and also in the presence of the reductant dithiothreitol (DTT). Transparent viscoelastic gels form at low pH values while opaque gels form under alkaline conditions. No increase in viscosity was observed for systems in pure water unless 20 mM of DTT was added, which is known to break the disulfide bridges present in HEWL. The microstructure of the gel was studied using transmission electron microscopy (TEM) and environmental scanning electron microscopy (ESEM). Gels formed at low pH contain fibrils ∼10 nm in diameter with various lengths while at high pH the gels are dominated by particulate aggregates. Thinner fibrils that are 4-6 nm in diameter are observed in the gels formed in the presence of DTT. In this case the distinct feature of the gels is they are thermoreversible and can be melted and reformed easily by varying the temperature.

Structural and Morphological Transformation of NaX Zeolite Crystals at High Temperature

2007 ◽  
Vol 336-338 ◽  
pp. 405-408
Author(s):  
Young Mi Kim ◽  
Ik Jin Kim
Keyword(s):  
Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Morphological Transformation ◽  
Nax Zeolite ◽  
Large Size ◽  
Transmission Electron ◽  
Bet Analysis ◽  
Ft Ir ◽  
Zeolite Crystals

Well-shaped octahedral crystals of NaX zeolite of a large size of 30μm were synthesized by a hydrothermal method in a mother solution having a 3.5Na2O : Al2O3 : 2.1SiO2 : 593~2000H2O composition. Thermal treatment of NaX zeolite crystals results in the formation of an intermediate amorphous phase (T < 1000oC) and crystalline phase of aluminium silicate at temperature above 800 and 900oC. Environmental scanning electron microscopy (ESEM), High resolution Transmission Electron Microscopy (HRTEM), X-ray powder diffraction (XRD), Fourier transform infrared(FT-IR) spectroscopy, DTA/TGA and BET analysis were used to characterize the initial materials and the obtained products after various heat treatments.

Synthesis and Characterization of TMA-A Zeolite Nanocrystals

2007 ◽  
Vol 124-126 ◽  
pp. 563-566
Author(s):  
Young Mi Kim ◽  
Seok Ju Lee ◽  
Ik Jin Kim
Keyword(s):  
Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray ◽  
Transmission Electron ◽  
Bet Analysis ◽  
Ft Ir ◽  
Average Lattice ◽  
Ft Ir Spectroscopy

Well-controlled cubic nanocrystal of TMA-A zeolite with a size of 60~100 nm were synthesized by a hydrothermal method in a solution having a Al(i-pro)3 : 2.2 TEOS : 2.4 TMAOH: 0.3 NaOH : 200H2O composition. The single TMA-A nanocrystals has an average lattice constant of 24.61 Å having a surface area of 742.36 m2/g. Thermal treatment of TMA zeolite crystals results in the formation of an amorphous above 900oC. Environmental scanning electron microscopy (ESEM). high resolution transmission electron microscopy(HRTEM), X-ray powder diffraction(XRD), fourier transform infrared(FT-IR) spectroscopy, DTA/TGA and BET analysis were used to characterize the initial materials and the obtained products after various heat treatments.

Examination of Hard Segment and Soft Segment Phase Separation in Polyurethane Medical Materials by Electron Microscopy Techniques

2005 ◽  
Vol 12 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Jennifer E. Taylor ◽  
Peter R. Laity ◽  
Steven S. Wong ◽  
Keith Norris ◽  
Peck Khunkamchoo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hard Segment ◽  
Soft Segment ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Dynamic Surface ◽  
Transmission Electron ◽  
Medical Materials ◽  
Microscopy Techniques ◽  
Surface Morphologies

A combination of transmission electron microscopy (TEM) andin situtensile testing in an environmental scanning electron microscopy (ESEM) was used to evaluate the static bulk and dynamic surface morphologies of medical polyurethanes. TEM results showed phase-separated hard segment and soft segment structures. Surface morphology as a function of strain was studied using ESEM in conjunction with a tensometer.

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