Combined effects of SiO 2 ratio and purity on physical properties and microstructure of in situ alumina‐mullite ceramic

2021 ◽  
Author(s):  
Rafael Salomão ◽  
Leandro Fernandes ◽  
Natalia C. M. Spera
Keyword(s):  
Physical Properties ◽  
Combined Effects ◽  
Mullite Ceramic

scholarly journals Microstructural Characteristics of Frazil Particles and the Physical Properties of Frazil Ice in the Yellow River, China

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 617
Author(s):  
Yaodan Zhang ◽  
Zhijun Li ◽  
Yuanren Xiu ◽  
Chunjiang Li ◽  
Baosen Zhang ◽  
...  
Keyword(s):  
Physical Properties ◽  
Yellow River ◽  
The Yellow River ◽  
Ice Crystal ◽  
Microstructural Characteristics ◽  
Air Bubble ◽  
Frazil Ice ◽  
Sediment Content ◽  
Crystal Diameter

Frazil particles, ice crystals or slushy granules that form in turbulent water, change the freezing properties of ice to create “frazil ice”. To understand the microstructural characteristics of these particles and the physical properties of frazil ice in greater depth, an in situ sampler was designed to collect frazil particles in the Yellow River. The ice crystal microstructural characteristics of the frazil particles (morphology, size, air bubble, and sediment) were observed under a microscope, and their nucleation mechanism was analyzed according to its microstructure. The physical properties of frazil ice (ice crystal microstructure, air bubble, ice density, and sediment content) were also observed. The results showed that these microstructures of frazil particles can be divided into four types: granular, dendritic, needle-like, and serrated. The size of the measured frazil particles ranged from 0.1 to 25 mm. Compared with columnar ice, the crystal microstructure of frazil ice is irregular, with a mean crystal diameter less than 5 mm extending in all directions. The crystal grain size and ice density of frazil ice are smaller than columnar ice, but the bubble and sediment content are larger.

In situ polymerized poly(butylene succinate)/silica nanocomposites: Physical properties and biodegradation

2008 ◽  
Vol 93 (5) ◽  
pp. 889-895 ◽  
Author(s):  
Sang-Il Han ◽  
Jung Seop Lim ◽  
Dong Kook Kim ◽  
Mal Nam Kim ◽  
Seung Soon Im
Keyword(s):  
Physical Properties ◽  
Butylene Succinate ◽  
Silica Nanocomposites

scholarly journals Flow-law hypotheses for ice-sheet modeling

1992 ◽  
Vol 38 (129) ◽  
pp. 245-256 ◽  
Author(s):  
Richard B. Alley
Keyword(s):  
Physical Properties ◽  
Ice Sheets ◽  
Diffusion Control ◽  
Ice Streams ◽  
Ice Shelves ◽  
Dislocation Glide ◽  
Ice Sheet Modeling ◽  
Flow Law ◽  
Power Law Creep

AbstractIce-flow modeling requires a flow law relating strain rates to stresses in situ, but a flow law cannot be measured directly in ice sheets. Microscopic processes such as dislocation glide and boundary diffusion control both the flow law for ice and the development of physical properties such as grain-size andc-axis fabric. These microscopic processes can be inferred from observations of the physical properties, and the flow law can then be estimated from the microscopic processes.A review of available literature shows that this approach can be imperfectly successful. Interior regions of large ice sheets probably have depth-varying flow-law “constants”, with the stress exponent,n, for power-law creep less than 3 in upper regions and equal to 3 only in deep ice;nprobably equals 3 through most of the thickness of ice shelves and ice streams.

scholarly journals Influence of expanded graphite (EG) and graphene oxide (GO) on physical properties of PET based nanocomposites

2014 ◽  
Vol 16 (4) ◽  
pp. 45-50 ◽  
Author(s):  
Sandra Paszkiewicz ◽  
Małgorzata Nachman ◽  
Anna Szymczyk ◽  
Zdeno Špitalský ◽  
Jaroslav Mosnáček ◽  
...  
Keyword(s):  
Physical Properties ◽  
In Situ Polymerization ◽  
Crystallization Rate ◽  
Expanded Graphite ◽  
Exfoliated Graphene ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Agglomeration Of Nanoparticles ◽  
Graphite Sheets

Abstract This work is the continuation and refinement of already published communications based on PET/EG nanocomposites prepared by in situ polymerization1, 2. In this study, nanocomposites based on poly(ethylene terephthalate) with expanded graphite were compared to those with functionalized graphite sheets (GO). The results suggest that the degree of dispersion of nanoparticles in the PET matrix has important effect on the structure and physical properties of the nanocomposites. The existence of graphene sheets nanoparticles enhances the crystallization rate of PET. It has been confirmed that in situ polymerization is the effective method for preparation nanocomposites which can avoid the agglomeration of nanoparticles in polymer matrices and improve the interfacial interaction between nanofiller and polymer matrix. The obtained results have shown also that due to the presence of functional groups on GO surface the interactions with PET matrix can be stronger than in the case of exfoliated graphene (EG) and matrix.

Effect of soil physical properties on the long-term performance of planted Scots pine in Finnish Lapland

2010 ◽  
Vol 90 (3) ◽  
pp. 451-465 ◽  
Author(s):  
K. Mäkitalo ◽  
V. Alenius ◽  
J. Heiskanen ◽  
K. Mikkola
Keyword(s):  
Physical Properties ◽  
Water Content ◽  
Scots Pine ◽  
Soil Physical Properties ◽  
Height Growth ◽  
Site Preparation ◽  
Preparation Methods ◽  
Finnish Lapland

Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst.) forests dominate in Finnish Lapland. This study examined the long-term effects of soil physical properties and conditions measured in intact intermediate areas, as well as site preparation, on the survival and height growth of planted pine on eight experimental sites, 25-27 yr after reforestation. On the four originally spruce-dominated sites, pine survival was the highest on sites with a high soil air-filled porosity (AFP) near saturation (at -1 kPa), a high van Genuchten parameter, and a low soil water content (SWC) in situ, and height growth was the fastest on sites with a high soil AFP in situ and a high van Genuchten parameter n, and on sites reaching a soil AFP of ca. 0.20 m3 m-3 at a high matric potential after saturation. Survival, but not mean height, was enhanced on the spruce sites by intensive site preparation methods such as ploughing instead of lighter site preparation methods. On the four originally pine-dominated sites, site preparation affected the mean height but not survival. The use of SWC as a sole criterion for sites suitable for pine reforestation was tested and found to be uncertain. Key words: Boreal forest soils, soil water content, air-filled porosity, van Genuchten function, site preparation, reforestation, Scots pine

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