scholarly journals Impact of microstructure evolution on the difference between geometric and reactive surface areas in natural chalk

2018 ◽  
Vol 115 ◽  
pp. 151-159 ◽  
Author(s):  
Y. Yang ◽  
S. Bruns ◽  
S.L.S. Stipp ◽  
H.O. Sørensen
Keyword(s):  
Microstructure Evolution ◽  
Reactive Surface ◽  
Surface Areas ◽  
The Difference

Surface Microstructure Evolution Upon Silicidation of Ni(Pt) and the Different Responses to Metal Etch

2013 ◽  
Author(s):  
Wentao Qin ◽  
Dorai Iyer ◽  
Jim Morgan ◽  
Carroll Casteel ◽  
Robert Watkins ◽  
...  
Keyword(s):  
Thin Film ◽  
Oxide Film ◽  
Microstructure Evolution ◽  
Depth Profiling ◽  
Surface Microstructure ◽  
The Difference ◽  
Surface Microstructures ◽  
Pt Films

Abstract Ni(5 at.%Pt ) films were silicided at a temperature below 400 °C and at 550 °C. The two silicidation temperatures had produced different responses to the subsequent metal etch. Catastrophic removal of the silicide was seen with the low silicidation temperature, while the desired etch selectivity was achieved with the high silicidation temperature. The surface microstructures developed were characterized with TEM and Auger depth profiling. The data correlate with both silicidation temperatures and ultimately the difference in the response to the metal etch. With the high silicidation temperature, there existed a thin Si-oxide film that was close to the surface and embedded with particles which contain metals. This thin film is expected to contribute significantly to the desired etch selectivity. The formation of this layer is interpreted thermodynamically.

Sludge Conditioning: Effects of Sludge Biochemical Composition

1985 ◽  
Vol 17 (4-5) ◽  
pp. 505-515 ◽  
Author(s):  
P. T. Bowen ◽  
T. M. Keinath
Keyword(s):  
Lipid Content ◽  
Strong Correlation ◽  
Biochemical Composition ◽  
Carbohydrate Content ◽  
Reactive Surface ◽  
Low Correlation ◽  
Sludge Conditioning ◽  
The Difference ◽  
Polymer Interaction ◽  
Three Components

Variations in response of three different sludges to conditioning with organic polyelectrolytes were evaluated with respect to the carbohydrate, protein and lipid content of the sludges. These biochemicals comprise the surfaces of most sludges. The difference in the concentration of these compounds is intrinsic to the sludge type. Polymer Index (PI) , a measure of minimum polymer dose required to achieve maximum dewaterability, was statistically related to each of the three components. Carbohydrate content correlated most strongly with PI. As carbohydrate content increases, PI was found to decrease indicating better polymer performance. Biopolymers, which are composed mainly of carbohydrates may surround the cells forming a highly reactive surface. These exocellular materials also promote bioflocculation. Both actions result in a lower polymer requirement for destabilizing the sludge. Protein and lipid were not observed to have strong correlation with PI. Cellular surfaces and structures are composed of these components. The low correlation indicates these components are less favored than carbohydrates for polymer interaction.

Modeling and Simulation of Microstructure Evolution of Cast Mg Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1562-1568 ◽  
Author(s):  
Liang Huo ◽  
Zhi Qiang Han ◽  
Bai Cheng Liu
Keyword(s):  
Solute Transport ◽  
Magnesium Alloys ◽  
Microstructure Evolution ◽  
Local Equilibrium ◽  
Equilibrium Composition ◽  
Mg Alloy ◽  
Dendrite Morphology ◽  
Dendrites Growth ◽  
The Difference ◽  
Cast Magnesium

A cellular automaton (CA) model has been developed for simulating the microstructure evolution and dendrite morphology of cast magnesium alloys. The growth kinetics of dendrite tips is determined by the difference between local equilibrium composition and local actual composition obtained by solving the solute transport equation. Two sets of meshes, a hexagonal mesh and an orthogonal mesh, are used in the model to perform the simulation. The hexagonal mesh is used to perform CA calculation to reflect the texture of Mg alloy dendrites, and the orthogonal mesh is used to solve the solute transport equations. The model was applied to simulate single dendrite evolution and columnar dendrites growth of AZ91D Mg alloy, as well as multi-grain growth of Mg-10Gd-2Y-0.5Zr (wt%) Mg alloy. Permanent mold step-shaped castings of the two Mg alloys were poured and metallographic examinations were carried out for validating the present model. The simulation results agree well with metallographic results. The model can be applied to simulate the microstructure evolution and dendrite morphology of magnesium alloys.

scholarly journals Isochronal Phase Transformation in Bimodal Ti-55531

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 790 ◽  
Author(s):  
Fuwen Chen ◽  
Guanglong Xu ◽  
Kechao Zhou ◽  
Hui Chang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Activation Energy ◽  
Phase Transformation ◽  
Microstructure Evolution ◽  
Continuous Heating ◽  
Interface Curvature ◽  
The Difference ◽  
Treatment Procedures ◽  
And Control

Bimodal microstructures where globular α and acicular α phases are embedded in the β matrix are commonly used in industry-relevant Ti-55531. To optimize the performance of Ti-55531 through heat treatment, it is crucial to understand and control the phase transformation in the as-received bimodal Ti-55531 as well as its microstructure evolution. In this work, the isochronal phase transformations and microstructure evolution in the bimodal Ti-55531 during the continuous heating were systematically studied by combining dilatometry, XRD phase analyses, and SEM observation. The β → α transformation occurred at 678 K only with the acicular α. When the temperature was higher than 788 K, α → β transformation took place in two separate stages (i.e., αacicular → β and αglobular → β transformation). The dissolution of αglobular occurred after the dissolution of αacicular was completed. Due to the difference in the chemical composition and interface curvature between αacicular and αglobular, the average activation energy for αacicular → β transformation was lower than that for the αglobular → β transformation. The isochronal phase transformation and microstructure evolution during continuous heating in the present work could be used to optimize heat treatment procedures for desired mechanical properties.

scholarly journals High Efficient YVPO4 Luminescent Materials Activated by Europium

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 658
Author(s):  
Tamara Minakova ◽  
Sergey Mjakin ◽  
Vadim Bakhmetyev ◽  
Maxim Sychov ◽  
Ilya Zyatikov ◽  
...  
Keyword(s):  
Specific Surface ◽  
Particle Surface ◽  
Synthesis Method ◽  
Luminescent Materials ◽  
Acid Base ◽  
Surface Areas ◽  
High Temperature Synthesis ◽  
High Efficient ◽  
Specific Surface Areas ◽  
The Difference

YPO4:Eu, YVO4:Eu, and YVPO4:Eu based phosphors with various Eu(III) activator contents and phosphate-vanadate ratios were synthesized by the self-propagating high-temperature synthesis method. The samples were characterized by scanning electron microscopy, nitrogen sorption, acid-base indicators and photoluminescence. The particle surface features with a finely dispersed structure comprising all the involved elements. The pore structure and the specific surface areas of the samples were different depending on the compositions of the samples. The most finely dispersed sample was YVO4:Eu samples. The specific surface areas of the YPO4:Eu samples were 10 to 15 times greater than those of vanadate samples. The phosphors samples had a slightly basic (YVO4:Eu, YVPO4:Eu) or slightly acidic (YPO4:Eu) properties of the surface with different contents of Lewis and Brönsted sites. The differences in the compositions and acid-base state resulted in the difference in the intensity and brightness of the photoluminescence (PL) of the samples. The yttrium-phosphate-vanadate phosphors of the mixed YVxP1−xO4-Eu had higher brightness and PL intensity than those samples with similar phosphate as well as vanadate phosphors.

Microstructure and Mechanical Properties of Al-0.5 at.% X (=Si, Ag, Mg) Alloys Highly Deformed by ARB Process

2008 ◽  
Vol 584-586 ◽  
pp. 547-552 ◽  
Author(s):  
Daisuke Terada ◽  
Toshiaki Masui ◽  
Naoya Kamikawa ◽  
Nobuhiro Tsuji
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Microstructure Evolution ◽  
High Purity ◽  
Uniform Elongation ◽  
Mg Alloys ◽  
The Other ◽  
Other Hand ◽  
The Difference ◽  
Lamellar Boundary

Effect of solid solution elements on microstructure evolution and mechanical properties was investigated using a high purity Al (purity 99.99%) and Al-0.5 at.% X ( X = Si, Ag, Mg ) alloys deformed by accumulative roll bonding (ARB) process up to 7 cycles (equivalent strain of 5.6) at ambient temperature. The ARB-processed high purity Al showed the equiaxed microstructure having mean grain size of 750 nm. On the other hand, the microstructure of the ARB-processed Al-0.5at.%X alloys showed lamellar boundary structures elongated along RD. The mean lamellar boundary spacing significantly differed depending on the alloying elements, which suggested that solute atoms had a significant effect on microstructure evolution. The difference in the grain size was regarded to be caused by the difference in recovery processes in the alloys. The tensile strength of the alloys increased with increasing the number of ARB cycles. In the Al-Si and Al-Ag alloys, the post-uniform elongation increased with increasing the number of the ARB cycles. On the other hand, the elongation of the Al-Mg hardly changed during the ARB process.

Relative benthic disturbances of conventional and novel otter boards

2015 ◽  
Vol 72 (8) ◽  
pp. 2450-2456 ◽  
Author(s):  
Matthew J. McHugh ◽  
Matt K. Broadhurst ◽  
David J. Sterling ◽  
Russell B. Millar ◽  
Greg Skilleter ◽  
...  
Keyword(s):  
Surface Area ◽  
Angle Of Attack ◽  
Base Plate ◽  
Benthic Fish ◽  
Bottom Contact ◽  
Surface Areas ◽  
The Difference ◽  
Australian Estuary ◽  
Quantitative Assessments

Abstract Reducing otter-board angle of attack (AOA) has been proposed as a way to limit the habitat impacts of demersal trawls, but there are few quantitative assessments. This study tested the hypothesis that a novel otter-board design, termed the “batwing” (comprising a 0.1-m wide sled with an offset sail at 20° AOA) would have relatively fewer bottom impacts than a conventional flat-rectangular otter board (35° AOA, with a similar hydrodynamic spreading force). Pairs of each otter board were suspended beneath a purpose-built rig comprising a beam and posterior semi-pelagic collection net and repeatedly deployed across established trawl grounds in an Australian estuary. Compared with the conventional otter boards, the batwings displaced significantly fewer empty shells (Anadara trapezia and Spisula trigonella) by 89% and school prawns (Metapenaeus macleayi) by up to 78%. These rates were similar to the difference in base-plate bottom contact (87%). Further, the batwing damaged proportionally fewer damaged shells, attributed to their displacement away from the board's surface area. Other debris (lighter pieces of wood) and benthic fish (bridled gobies, Arenigobius bifrenatus) were not as greatly mobilised (i.e. reduced by 50 and 25%, respectively); possibly due to their position on or slightly off the bottom, and a similar influence of hydrodynamic displacement by the hydro-vane surface areas. Although the consequences of reducing otter-board bottom contact largely remain unknown, low AOA designs like the batwing may represent a practical option for fisheries where trawling is perceived to be hazardous to sensitive habitats.

scholarly journals Comparative Study of Pore Structure Characteristics between Mudstone and Coal under Different Particle Size Conditions

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8435
Author(s):  
Jianguo Zhang ◽  
Xiyuan Li ◽  
Jihong Jiao ◽  
Jianbao Liu ◽  
Feng Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Pore Structure ◽  
Mercury Intrusion Porosimetry ◽  
Coal Bed ◽  
Particle Sizes ◽  
N2 Adsorption ◽  
Structure Characteristics ◽  
Surface Areas ◽  
The Difference ◽  
And Migration

In order to investigate the difference of pore structure characteristics between mudstone and coal under different particle size conditions, samples acquired from Henan province were smashed and screened into three different particle sizes (20–40, 80–100, and >200 mesh) to conduct the experiments, using the high-pressure mercury intrusion porosimetry (MIP) and low-temperature N2 adsorption (LT-N2A) techniques. The results demonstrated that the proportion of open pores or semi-enclosed pores increased, and the pores became preferable contacted each other for both mudstone and coal during the crushing process. These variations of pore structure characteristics in the coal were beneficial to methane storage and migration. The total specific surface areas and pore volumes all showed a tendency of increasing continually for both mudstone and coal, as the particle sizes decreased from the LT-N2A test. The mudstone and coal were non-rigid aggregates with micropores, plate-shaped pores, and slit-shaped pores developed inside. The effect of the crushing process on the pore shape for the mudstone and coal was inappreciable. Moreover, the influence of the particle sizes on the mesopore was the most significant, followed by the macropore; and on the micropore, the influence was negligible for both mudstone and coal. The crushing process only had a significant impact on the pore structure of mudstone with a particle size of less than 100 mesh, while it could still alter the pore structure of coal with a particle size of larger than 100 mesh. It is believed that this work has a significant meaning to explore the diffusion and migration rules of coal-bed methane in coal.

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