Mechanical and microstructural characterization of poly(N-isopropylacrylamide) hydrogels and its nanocomposites

2021 ◽  
pp. 146442072098830
Author(s):  
Necmi Dusunceli ◽  
Catalina Gabriela Sanporean ◽  
Aleksey D Drozdov ◽  
Jesper de Claville Christiansen ◽  
Florina-Elena Comanici
Keyword(s):  
Mechanical Behavior ◽  
Microstructural Analysis ◽  
Compressive Loading ◽  
Microstructural Characterization ◽  
Ammonium Persulfate ◽  
Mechanical Responses ◽  
Highly Nonlinear ◽  
Nonlinear Mechanical ◽  
The Mathematical Model

Mechanical behavior dependency of the poly(N-isopropylacrylamide) hydrogel related to the amount of initiator, crosslinker, and nanoparticles was investigated. An experimental approach has been undertaken to observe these dependencies and assess the amount of initiator (ammonium persulfate), crosslinker (N, N′-methylene-bisacrylamide), and nanoparticles (graphene oxide) on the macroscopic responses of poly(N-isopropylacrylamide). Different amounts of initiator, crosslinker, and nanoparticle were used to manufacture specimens for the compression test. The specimens were subjected to compressive loading up to breakage to investigate the breaking behavior of poly(N-isopropylacrylamide). The responses of these specimens indicated that the mechanical behavior of poly(N-isopropylacrylamide) was highly nonlinear and depends on these ingredients. The mechanical responses of poly(N-isopropylacrylamide) were simulated using the ideal network model. The simulation results of the mathematical model substantially complied with the experimental data of poly(N-isopropylacrylamide). In addition, a more in-depth microstructural analysis was performed on these specimens. The analysis results allowed us to correlate the dependent amounts of the ingredients on the nonlinear, mechanical behavior of poly(N-isopropylacrylamide).

Microstructural characterization of AIN sintered with Y2O3

1988 ◽  
Vol 46 ◽  
pp. 578-579
Author(s):  
S-K. Chiang
Keyword(s):  
Microstructural Analysis ◽  
Microstructural Characterization ◽  
Packaging Material ◽  
Oxygen Impurity ◽  
Microstructural Investigation ◽  
Intergranular Phase ◽  
Processing History ◽  
Triple Points ◽  
Standard Techniques

Aluminum nitride's high thermal but low electrical conductivity make it a potential ceramic packaging material. Processing history, however, can have significant effects on these properties and studies aimed at correlating them to the processing and microstructure are sparse.Pure AIN cannot be readily sintered without additives. Addition of Y2O3 significantly improves its densification behavior and the results presented here concern microstructural analysis of AIN sintered with Y2O3.High-purity AIN powder (containing 1.24% oxygen impurity) with 3 or 9 weight% Y2O3 added was sintered in N2 at 1850°C for 1 hour followed by a further 3 hours at 1900°C. Samples made using this treatment were >95% dense. Specimens for microstructural investigation were prepared using standard techniques and examined using a JEOL 200 CX AEM.The general microstructure of all specimens consists of AIN grains with pockets of intergranular phase(s) located at triple points and some grain boundaries (FIG. 1).

Synthesis and Microstructural Analysis of Si3N4 Nanorods

2002 ◽  
Vol 8 (1) ◽  
pp. 5-10 ◽  
Author(s):  
Y.H. Gao ◽  
Y. Bando ◽  
K. Kurashima ◽  
T. Sato
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Activated Carbon ◽  
Carbothermal Reduction ◽  
Microstructural Analysis ◽  
Microstructural Characterization ◽  
X Ray ◽  
Transmission Electron ◽  
Closest Packing

α-Si3N4 nanorods with 20–80 nm width were synthesized by carbothermal reduction of SiO with amorphous activated carbon (AAC) as a reductant. Microstructural characterization of the synthesized nanorods was carried out by high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray analysis. Many Si3N4 nanorods were found to be twisted. Each twisted nanorod contained several straight Si3N4 parts. The straight parts had the rod axes orientated along the 〈1010〉 direction, which is the closest packing direction of α-Si3N4. There were two kinds of joints between the two adjacent straight Si3N4 parts. Formation mechanism of the Si3N4 nanorods is discussed.

Effect of Parawood Ash on Drying Shrinkage, Compressive Strength and Microstructural Characterization of Metakaolin-Based Geopolymer Mortar

2013 ◽  
Vol 594-595 ◽  
pp. 411-415 ◽  
Author(s):  
Danupon Tonnayopas ◽  
Abideng Hawa ◽  
Woraphot Prachasaree ◽  
Pichai Taneerananon
Keyword(s):  
Compressive Strength ◽  
Microstructural Analysis ◽  
Drying Shrinkage ◽  
Microstructural Characterization ◽  
Partial Replacement ◽  
X Ray Diffraction ◽  
Microscopy Techniques ◽  
Metakaolin Geopolymer ◽  
Test Result

Drying shrinkage, compressive strength and microstructural analysis of metakaolin based geopolymers partial replacement with Parawood ash was investigated. It was involved different SiO2/Al2O3 and CaO/SiO2 ratios. Characterization of geopolymer mortar was determined on drying shrinkage, compressive strength, mineral phases and microstructure was analysed by X-ray diffraction and scanning electron microscopy techniques. Test result of highest compressive strength was about 71 MPa at 6-h (4-h in oven at 80oC and 2-h ambient temperature). Voids-cement ratio is the most effect on the unconfined compressive strength of this metakaolin geopolymer mortar.

Microstructural Characterization of Clay-Based Ceramics with the Addition of Granite Residues

2019 ◽  
Vol 958 ◽  
pp. 123-128
Author(s):  
Monica Castoldi Borlini Gadioli ◽  
Mariane Costalonga de Aguiar ◽  
Carlos Maurício Fontes Vieira ◽  
Fabio da Costa Garcia Filho ◽  
Sergio Neves Monteiro
Keyword(s):  
Microstructural Analysis ◽  
High Capacity ◽  
Microstructural Characterization ◽  
Ceramic Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ornamental Stones ◽  
Lower Porosity ◽  
Scanning Electron

Million tons of ornamental stones residues are produced every year. Most of this residue is disposed without any kind of processing or treatment. Moreover, disposal occurs without a prospective of reuse or recycling. The incorporation into ceramics is a possible alternative for part of this residue. Clay-based ceramics have high capacity of incorporation of industrial residues. This work aimed to conduct a microstructural characterization of clay-based ceramics with incorporation of granite residues in the composition of the ceramic matrix. Specimens were produced with the addition of 0, 10, 20 and 30 wt. % of granite residues. The specimens were prepared by uniaxial pressing and sintered at temperatures of 1050 and 1200°C. For the microstructural analysis were carried out by scanning electron microscopy and X-ray diffraction. The results indicated that the incorporated ceramics sintered at 1200oC presented higher densification and lower porosity as compared with those sintered at 1050oC.

A Numerical Method for Simulating Nonlinear Mechanical Responses of Tensegrity Structures Under Large Deformations

2013 ◽  
Vol 80 (6) ◽  
Author(s):  
Li-Yuan Zhang ◽  
Yue Li ◽  
Yan-Ping Cao ◽  
Xi-Qiao Feng ◽  
Huajian Gao
Keyword(s):  
Numerical Method ◽  
Large Scale ◽  
Large Deformations ◽  
Design Analysis ◽  
Tensegrity Structures ◽  
Mechanical Responses ◽  
Highly Nonlinear ◽  
Nonlinear Mechanical

An efficient numerical method is developed to analyze the mechanical responses of tensegrity structures subjected to various actuations that lead to large and highly nonlinear (e.g., hardening or softening) deformations. The proposed method, whose accuracy and efficacy are demonstrated through a number of representative examples, holds promise for applications in design, analysis, and safety evaluations of large-scale tensegrity structures.

scholarly journals Mechanical behavior and microstructural characterization of different zirconia polycrystals in different thicknesses

2021 ◽  
Vol 13 (6) ◽  
pp. 385
Author(s):  
Laura Viviana Calvache Arcila ◽  
Nathália de Carvalho Ramos ◽  
Tiago Moreira Bastos Campos ◽  
Kiara Serafini Dapieve ◽  
Luiz Felipe Valandro ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Microstructural Characterization

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

Microstructural Characterization of Au-Ge-Ni based ohmic contacts to GaAs/AlGaAs modfet device

1987 ◽  
Vol 45 ◽  
pp. 326-327
Author(s):  
A.K. Rai ◽  
A.K. Petford-Long ◽  
A. Ezis ◽  
D.W. Langer
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Microstructural Characterization ◽  
Almost Everywhere ◽  
Spacer Layer ◽  
Good Contact ◽  
The Relationship ◽  
Lower Contact

Considerable amount of work has been done in studying the relationship between the contact resistance and the microstructure of the Au-Ge-Ni based ohmic contacts to n-GaAs. It has been found that the lower contact resistivity is due to the presence of Ge rich and Au free regions (good contact area) in contact with GaAs. Thus in order to obtain an ohmic contact with lower contact resistance one should obtain a uniformly alloyed region of good contact areas almost everywhere. This can possibly be accomplished by utilizing various alloying schemes. In this work microstructural characterization, employing TEM techniques, of the sequentially deposited Au-Ge-Ni based ohmic contact to the MODFET device is presented.The substrate used in the present work consists of 1 μm thick buffer layer of GaAs grown on a semi-insulating GaAs substrate followed by a 25 Å spacer layer of undoped AlGaAs.

Microstructural characterization of a cast RENi5-based alloy

1993 ◽  
Vol 51 ◽  
pp. 1176-1177
Author(s):  
G. M. Micha ◽  
L. Zhang
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Microstructural Characterization ◽  
Binary Compound ◽  
Nickel Metal ◽  
Cast Material ◽  
Nickel Metal Hydride ◽  
Transmission Electron ◽  
Cast Condition

RENi5 (RE: rare earth) based alloys have been extensively evaluated for use as an electrode material for nickel-metal hydride batteries. A variety of alloys have been developed from the prototype intermetallic compound LaNi5. The use of mischmetal as a source of rare earth combined with transition metal and Al substitutions for Ni has caused the evolution of the alloy from a binary compound to one containing eight or more elements. This study evaluated the microstructural features of a complex commercial RENi5 based alloy using scanning and transmission electron microscopy.The alloy was evaluated in the as-cast condition. Its chemistry in at. pct. determined by bulk techniques was 12.1 La, 3.2 Ce, 1.5 Pr, 4.9 Nd, 50.2 Ni, 10.4 Co, 5.3 Mn and 2.0 Al. The as-cast material was of low strength, very brittle and contained a multitude of internal cracks. TEM foils could only be prepared by first embedding pieces of the alloy in epoxy.

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