Effect of the Processing Parameters on the Fabrication of MgAl2O4 Foams

Stable MgAl2O4 foams (7–21 vol.%) were manufactured using a natural extract from the pericarp of the soap-nut fruit, saponin being the main component, as the foaming agent. The soap-nut extract is soluble in water, biodegradable, non-toxic, and has similar properties to commercial tensoactives. The stability and characteristics of the porous structure of the ceramic foams were evaluated in terms of the amount of foaming agent, content of MgAl2O4 particles, time and speed of stirring of the slurry, type of agitator, and drying temperature. It was found that the foaming capacity decreased with the percent of foaming agent and ceramic, whereas the time and speed of stirring enhanced the foamability. Foaming trials showed that stirring aqueous slurries with 3 wt.% of soap-nut extract for 2 min at 1070 or 2120 rpm, depending on the type of agitator, produced stable MgAl2O4 foams when drying at 60 °C. The mechanism of foaming is discussed. The foams were sintered at 1400 °C for 1 h under an Ar atmosphere. Observation of the sintered foam structures in the scanning electron microscope revealed nearly spherical cells with very good interconnectivity and strength to be manipulated, making them suitable as preforms for manufacturing Al-based composites by pressureless infiltration.

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A new species of Cribraria (Myxomycetes) from Australia

Novosti sistematiki nizshikh rastenii ◽

10.31111/nsnr/2018.52.2.379 ◽

2018 ◽

Vol 52 (2) ◽

pp. 379-385 ◽

Cited By ~ 1

Author(s):

S. L. Stephenson ◽

Yu. K. Novozhilov ◽

P. Wellman

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

New Species ◽

Lemon Yellow ◽

Moist Chamber ◽

Light Yellow ◽

Dark Violet ◽

The Stability ◽

A New Species ◽

Scanning Electron

A new species of Cribraria, described herein as C. bicolor, appeared in moist chamber cultures on samples of the bark of Eucalyptus sp. collected at two localities in Australia. The morphology of representative specimens was examined by light and scanning electron microscopy, and micrographs of relevant morphological details of sporocarps and spores are provided. The species has a number of distinct and unique morphological features, including a glossy bright-violet globose sporotheca and a two-colored long stalk which is bright-red over the lower one-third and light yellow or lemon-yellow over the upper two-thirds. The combination of these characteristics as well as a shallow calyculus which is dark-violet when viewed under a dissecting microscope and bright red in transmitted light when mounted in lactophenol makes C. bicolor a well-defined morphospecies when compared to all other species of Cribraria. The stability of the taxonomic characters of the species was confirmed by an examination of a number of specimens.

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The force effects of two types of polyethylene terephthalate glyc-olmodified clear aligners immersed in artificial saliva

Scientific Reports ◽

10.1038/s41598-021-89425-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Biao Xiang ◽

Xingxing Wang ◽

Gang Wu ◽

Yichen Xu ◽

Menghan Wang ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Polyethylene Terephthalate ◽

Artificial Saliva ◽

Orthodontic Force ◽

The Mean ◽

The Stability ◽

Scanning Electron

AbstractNumerous factors can influence the force exerted by clear aligners on teeth. This study aimed to investigate the stability of the force delivered by two different material appliances. 90 clear aligners with 2 materials and three different activations were designed and fabricated. Then, a device was employed to measure the force generated by the two types of PET-G material appliances immersed in artificial saliva for 0, 3, 7, 10, 14 days. Scanning electron microscopy was applied to observe the morphologic alterations on the aligner surfaces, respectively. The forces generated by different activation appliance exhibited differently, 0.0 mm < 0.1 mm < 0.2 mm. In addition, increasing the immersion times and the orthodontic force also decreased, but the forces decreased differently. Compared with the forces of conventional PETG appliances with 0.20 mm activation, the modified PETG appliances with the same activation exhibited significantly higher mean force. When comparing the mean force for modified PETG appliances after 10 and 14 days with conventional PETG appliances, the delivery forces exhibited significant differences (P < 0.05). The force delivered by both materials decreased obviously following artificial saliva immersion, and the force generated by modified aligners exhibited better stability than conventional aligners.

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Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part I: Membrane Synthesis and Characterization

Nanomaterials ◽

10.3390/nano11030607 ◽

2021 ◽

Vol 11 (3) ◽

pp. 607

Author(s):

Carolina Hermida-Merino ◽

Fernando Pardo ◽

Gabriel Zarca ◽

João M. M. Araújo ◽

Ane Urtiaga ◽

...

Keyword(s):

Polymer Membranes ◽

Small Addition ◽

Polymeric Membranes ◽

Synthesis And Characterization ◽

Complete Disappearance ◽

Optical Profilometry ◽

Scanning Calorimetry ◽

Exfoliated Graphene ◽

The Stability ◽

Scanning Electron

In this work, polymeric membranes functionalized with ionic liquids (ILs) and exfoliated graphene nanoplatelets (xGnP) were developed and characterized. These membranes based on graphene ionanofluids (IoNFs) are promising materials for gas separation. The stability of the selected IoNFs in the polymer membranes was determined by thermogravimetric analysis (TGA). The morphology of membranes was characterized using scanning electron microscope (SEM) and interferometric optical profilometry (WLOP). SEM results evidence that upon the small addition of xGnP into the IL-dominated environment, the interaction between IL and xGnP facilitates the migration of xGnP to the surface, while suppressing the interaction between IL and Pebax®1657. Fourier transform infrared spectroscopy (FTIR) was also used to determine the polymer–IoNF interactions and the distribution of the IL in the polymer matrix. Finally, the thermodynamic properties and phase transitions (polymer–IoNF) of these functionalized membranes were studied using differential scanning calorimetry (DSC). This analysis showed a gradual decrease in the melting point of the polyamide (PA6) blocks with a decrease in the corresponding melting enthalpy and a complete disappearance of the crystallinity of the polyether (PEO) phase with increasing IL content. This evidences the high compatibility and good mixing of the polymer and the IoNF.

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A Novel Approach to Fabricate Foam Ceramics from Steel Slag

Advances in Materials Science and Engineering ◽

10.1155/2020/4649082 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Yu Zheng ◽

Xudong Luo ◽

Jinlong Yang ◽

Wenlong Huo ◽

Chi Kang

Keyword(s):

Compressive Strength ◽

Ph Value ◽

Steel Slag ◽

Raw Material ◽

Solid Loading ◽

Insulation Material ◽

Ceramic Foams ◽

Novel Approach ◽

The Stability ◽

First Time

A novel approach is used for fabricating steel slag foam ceramics based on the particle-stabilized foaming method. In this work, steel slag was used as the raw material and propyl gallate (PG) was used as the surface modifier. For the first time, steel slag ceramic foams were successfully fabricated based on particle-stabilized foams. The results show that the stability of the ceramic foams was closely related to the pH value and PG concentration. The porosity and compressive strength could be controlled by changing the solid loading of steel slag and sintering temperature. The porosity of steel slag foam ceramics ranged from 85.6% to 62.53%, and the compressive strength was from 1.74 MPa to 10.42 MPa. The thermal conductivity of steel slag foam ceramics was only 0.067 W (m·K)−1, which shows that it could be used as a thermal insulation material.

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The Photoluminescence Enhancement and Stability of Porous Silicon by Cathodic Reduction and Acid Treatment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.887-888.458 ◽

2014 ◽

Vol 887-888 ◽

pp. 458-461

Author(s):

Chang Qing Li ◽

Kun Wang ◽

Pei Jia Liu ◽

Qi Ming

Keyword(s):

Electron Microscope ◽

Porous Silicon ◽

Acid Treatment ◽

Cathodic Reduction ◽

Luminescence Properties ◽

Sem Images ◽

Photoluminescence Enhancement ◽

The Stability ◽

Scanning Electron ◽

Cathode Reduction

Porous silicon (PSi) was fabricated by using electrochemical anodic etching method. Then acid treatment and cathode reduction treatment were employed to improve the luminescence properties and stability of PSi material. Photoluminescence (PL) measurements and scanning electron microscope (SEM) were used to observe the luminescence properties and microstructure of samples, respectively. The results of PL measurements showed that the PL intensity and the stability of luminescence of samples after cathodic reduction and acid treatment were significantly improved. The SEM images showed that the porosity of PSi may be increased through the cathodic reduction treated.

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Identification of Nd163 phase in melt-textured NdBa2Cu3O7−δ bulk samples

Journal of Materials Research ◽

10.1557/jmr.2003.0288 ◽

2003 ◽

Vol 18 (9) ◽

pp. 2050-2054 ◽

Cited By ~ 4

Author(s):

Marcello Gombos ◽

Vicente Gomis ◽

Anna Esther Carrillo ◽

Antonio Vecchione ◽

Sandro Pace ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Optical Microscopy ◽

Room Temperature ◽

Polarized Light ◽

Energy Dispersive ◽

X Ray ◽

Spontaneous Formation ◽

The Stability ◽

Scanning Electron

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.

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Influence of Processing Parameters and Different Content of Tib2 Ceramics on the Properties of Composites Sintered by High Pressure -High Temperature (HP-HT) Method

Archives of Metallurgy and Materials ◽

10.2478/amm-2014-0033 ◽

2014 ◽

Vol 59 (1) ◽

pp. 205-209 ◽

Cited By ~ 17

Author(s):

I. Sulima ◽

L. Jaworska ◽

P. Figiel

Keyword(s):

High Pressure ◽

High Temperature ◽

Processing Parameters ◽

Structure Changes ◽

High Pressure High Temperature ◽

Mechanical And Physical Properties ◽

Temperature And Pressure ◽

Different Content ◽

Scanning Electron ◽

Properties Of Composites

Abstract In this paper the properties of the austenitic stainless steel reinforced with various volume fractions of TiB2 ceramics have been studied. The high pressure- high temperature (HP-HT) method of sintering was applied to the formation of composites. Samples were sintered at pressure of 5 and 7 ±0.2 GPa and temperatures of 1273 K and 1573 K. For the tested materials, the relative density, Young’s modulus and hardness were measured. In order to investigate the structure changes, the scanning electron microscope was used. The obtained results show that the temperature and pressure influence on the mechanical and physical properties of the investigated composites.

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Study on the Calamine/Sodium Alginate Modified Viscose Fiber

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.418-420.192 ◽

2011 ◽

Vol 418-420 ◽

pp. 192-195

Author(s):

Dong Qi Liu ◽

Ying Liu ◽

Shu Fa Han ◽

Yu Feng Zhang ◽

Cui Yu Yin

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Sodium Alginate ◽

Mechanical Performance ◽

Viscose Fiber ◽

Alginate Solution ◽

Fiber Properties ◽

Injection Methods ◽

The Stability ◽

Scanning Electron

In this article we successfully prepared calamine / sodium alginate viscose fiber. Good dispersion and stability of the modified solution was prepared by dispersing calamine in alkaline solution of sodium alginate, and then mixed it with viscose spinning solution by spinning injection methods. Moreover, the stability of calamine / sodium alginate solution, the effect of concentration of calamine on the fiber properties is studied in this paper. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and physical mechanical performance are test to characterize the structure and the performance of the calamine / sodium alginate viscose fiber.

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Water Based Colloidal Processing of Ceramic Laminates

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.333.39 ◽

2007 ◽

Vol 333 ◽

pp. 39-48 ◽

Cited By ~ 6

Author(s):

Antonio Javier Sanchez-Herencia

Keyword(s):

Processing Parameters ◽

Colloidal Processing ◽

Water Separation ◽

Green Strength ◽

Water Based ◽

The Stability ◽

Deflection Criteria ◽

Joining Strength ◽

Processing Techniques ◽

Laminated Structures

Multilayered materials and coating are complex structures proposed among others to face the structural requirements of ceramics. The development of reinforcement mechanism by laminated structures can be due to deflection criteria or to the presence of residual stresses and requires of tailored laminates. These designs are characterized by the phases, thickness and distribution of the layers as well as the joining strength between them. In this sense water based colloidal processing techniques are used to fabricate layered structures by consolidating the layers from fluid dispersions of the powders in water. In these processing methods the phases presented in the final laminate are mainly given by the composition of the starting slurries while the changes in thickness and sharpness of the layers are controlled by acting on the processing parameters. The achievement of stable slurries is a shared step for all the colloidal processing techniques. In the water based slurries the stability will be dominated by the polar media, the surface behavior of the particles and the presence of dispersant additives to increase the repulsion between particles. The stable slurry ensures an effective milling and dispersion of the phases as well as high solid loadings, if required. Further processes associated to shaping and consolidation of the layers requires the incorporation of additives and-or water removal. The shaping methods based on aqueous slurries can be classified taking into account the process of solid-water separation. For each of those shaping methods, the nature and amount of the additives is different in order to get the optimum rheological behavior and green strength after drying. Depending on the thickness of layers and coatings as well as the shape and dimensions of the samples, the shaping method can be selected alone and combined with others.

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Hydroxypropylsulfonation/Caproylation of Cornstarch to Enhance Its Adhesion to PLA Fibers for PLA Sizing

Polymers ◽

10.3390/polym11071197 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1197 ◽

Cited By ~ 8

Author(s):

Wei Li ◽

Jie Wu ◽

Xingui Cheng ◽

Lanjuan Wu ◽

Zhi Liu ◽

...

Keyword(s):

Electron Microscopy ◽

Internal Stress ◽

Mechanical Behaviors ◽

Cohesive Failure ◽

Adhesive Layers ◽

Adhesion Measurement ◽

Acid Sodium Salt ◽

The Stability ◽

The Impact ◽

Scanning Electron

The impact of hydroxypropylsulfonation/caproylation on the adhesion of cornstarch to polylactic acid (PLA) fibers was investigated for ameliorating the applications such as PLA sizing. The hydroxypropylsulfonated and caproylated cornstarch (HCS) samples with different degrees of substitution (DS) were synthesized by a hydroxypropylsulfonation of acid-converted cornstarch (ACS) with 3-chloro-2-hydroxy-1-propanesulfonic acid sodium salt (CHPS-Na) and subsequently a caproylation with caproic anhydride (CA). The HCS granules were characterized by Fourier transform infrared spectroscopic and scanning electron microscopy. The adhesion was evaluated by measuring the bonding forces of the PLA roving impregnated. The mechanical behaviors of the adhesive layers were estimated by determining the properties of the films. The results of adhesion measurement were also analyzed especially through the wetting and spreading of the paste on the fiber surfaces, as well as the failure type, internal stress and mechanical behaviors of the adhesive layers among fibers. Additionally, apparent viscosity and its stability of the pastes were also determined. It was found that hydroxypropylsulfonation/caproylation was not only able to obviously improve the adhesion of ACS to PLA fibers, but also capable of further improving the adhesion of hydroxypropylsulfonated starch (HS) to the fibers. With the rise in the total DS, the adhesion gradually increased. The two substituents improved the wetting and spreading, reduced the internal stress, lowered the probabilities of interfacial failure and cohesive failure, decreased the film brittleness, and increased the van der Waals force at the interfaces. Moreover, the HCS samples with a stability of above 85% could meet the demand on the stability for sizing. Considering the experimental results of the adhesion and the analysis of the results, HCS showed potential in the application of PLA sizing.

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