Environmental magnetism as a stream sediment tracer: an interpretation of the methodology and some case studies

Soil Research ◽  
1998 ◽  
Vol 36 (1) ◽  
pp. 167 ◽  
Author(s):  
R. H. Crockford ◽  
P. M. Fleming
Keyword(s):  
Grain Size ◽  
Case Studies ◽  
Environmental Magnetism ◽  
Extensive Discussion ◽  
Remanent Magnetisation ◽  
Grain Sizes ◽  
South Wales ◽  
Wide Range ◽  
River Confluences ◽  
The Difference

A comprehensive sediment sampling program was undertaken in the upper Molonglo catchment in south-eastern New South Wales to determine if mineral magnetics could be used to estimate sidestream contribution at river confluences in this environment. Some 12 confluences were examined over 1400 km 2 in 2 major basins and over 2 contrasting geological types. Sediment samples were divided into 7 size classes and the following magnetic properties measured: magnetic susceptibility at 2 frequencies, isothermal remanent magnetisation at 3 flux densities, and anhysteristic remanent magnetisation. The sidestream inputs were calculated for each particle size class from the range of magnetic parameters. Significant discrepancies and differences appeared in the resultant sidestream inputs, and this paper outlines the conclusions as to the reliability of the different analytical procedures. It is shown that both the concentration and magnetic grain size of ferrimagnetic minerals in the sediments must be taken into account. Where the difference in magnetic grain size between the upstream and sidestream sediments is small, the use of parameter crossplots or bulked magnetic ratios is generally not appropriate. The use of mass (concentration) magnetic values may be better. The difference in the demands of the crossplots and mass values methods is that crossplots require a wide range of mass magnetic concentrations in each branch, with the upstream and sidestream sediments having different magnetic grain sizes, whereas the mass values procedure does best with a very limited (but different) range of concentrations at the upstream and sidestream branches, but similar magnetic grain sizes. This paper provides an extensive discussion of the estimation technique using different parameter combinations, and uses 3 contrasting confluences as case studies.

The Processing of Ultrafine-Grained Materials Using High-Pressure Torsion

2007 ◽  
Vol 558-559 ◽  
pp. 1283-1294 ◽  
Author(s):  
Cheng Xu ◽  
Z. Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Metallic Materials ◽  
Grain Sizes ◽  
Ultrafine Grained ◽  
Wide Range ◽  
Ultrafine Grained Materials ◽  
Thin Disks

It is now well-established that processing through the application of severe plastic deformation (SPD) leads to a significant reduction in the grain size of a wide range of metallic materials. This paper examines the fabrication of ultrafine-grained materials using high-pressure torsion (HPT) where this process is attractive because it leads to exceptional grain refinement with grain sizes that often lie in the nanometer or submicrometer ranges. Two aspects of HPT are examined. First, processing by HPT is usually confined to samples in the form of very thin disks but recent experiments demonstrate the potential for extending HPT also to bulk samples. Second, since the strains imposed in HPT vary with the distance from the center of the disk, it is important to examine the development of inhomogeneities in disk samples processed by HPT.

Electroplated Cu Recrystallization in Damascene Structures at Elevated Temperatures

1999 ◽  
Vol 564 ◽  
Author(s):  
Qing-Tang Jiang ◽  
Michael E. Thomas ◽  
Gennadi Bersuker ◽  
Brendan Foran ◽  
Robert Mikkola ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Film Thickness ◽  
Grain Growth ◽  
Elevated Temperatures ◽  
Retardation Effect ◽  
Cu Films ◽  
Grain Sizes ◽  
Geometrical Constraints ◽  
The Difference

AbstractTransformations in electroplated Cu films from a fine to course grain crystal structure (average grain sizes went from ∼0.1 µm to several microns) were observed to strongly depend on film thickness and geometry. Thinner films underwent much slower transformations than thicker ones. A model is proposed which explains the difference in transformation rates in terms of the physical constraint experienced by the film since grain growth in thinner films is limited by film thickness. Geometrical constraints imposed by trench and via structures appear to have an even greater retardation effect on the grain growth. Experimental observations indicate that it takes much longer for Cu in damascene structures to go through grain size transformations than blanket films.

Effect of Low-Temperature Aging on Thermally-Induced Phase Transformation of NiTi Wire with a Wide Range of Grain Sizes

2021 ◽  
Vol 1042 ◽  
pp. 9-16
Author(s):  
Zhi Hao Zhao ◽  
Jian Ping Lin ◽  
Jun Ying Min ◽  
Yong Hou ◽  
Bo Sun
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
Low Temperature ◽  
Thermally Induced ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Wide Range ◽  
Low Temperature Aging ◽  
Niti Wires ◽  
Temperature Aging

Thermally-induced phase transformation (PT) is of significance and value to the application of NiTi alloy components. Low-temperature aging (LTA) treatment was used to alter PT characteristics of NiTi alloys avoiding undesirable grain growth. Effect of LTA on PT of NiTi wires with a wide range of grain sizes from 34 nm to 8021 nm was investigated in this study. As the average grain size varies from 34 to 217 nm, the temperature of the B2↔R transformation increase as a result of LTA, and the increasing effect is more obvious at a larger grain size. For NiTi alloys with average grain sizes ranging from 523 to 1106 nm, transformation sequence changes from B2↔B19' to B2↔R due to LTA. For the sample with an average grain size of 2190 nm, the B2↔B19' transformation is replaced by B2↔R←B19' after LTA. When the average grain size is larger than 2190 nm, transformation sequence changes from B2↔B19' to B2↔R↔B19' after LTA. Transmission emission microscope observations reveal that the above-mentioned PT behavior correlates with the coupled effect of grain size and precipitation. The precipitation of Ni4Ti3 in the grains with a size smaller than ~150 nm is inhibited after LTA, the temperature of B2→R of samples with average GS smaller than ~150 nm still is elevated due to the inhomogeneous grain size of NiTi wires.

Elimination of membrane compliance in undrained triaxial testing. I. Measurement and evaluation

1993 ◽  
Vol 30 (5) ◽  
pp. 727-738 ◽  
Author(s):  
P.G. Nicholson ◽  
R.B. Seed ◽  
H.A. Anwar
Keyword(s):  
Grain Size ◽  
Test Results ◽  
Factors Affecting ◽  
Grain Sizes ◽  
Wide Range ◽  
Specimen Density ◽  
Thin Membranes ◽  
Alternative Approaches ◽  
Measurement And Evaluation ◽  
Material Grain Size

Several alternative approaches have been suggested for evaluation and correction of the testing errors caused by membrane compliance. The degree to which membrane compliance may affect the results of an undrained test is a function of the soil grain size and overall geometry of the test specimen, as well as specimen density and range of effective confining stresses during a given test. Membrane-compliance effects may be negligible for fine sands and silts tested in conventional 71 mm diameter samples, since even very thin membranes cannot penetrate significantly into the small surficial voids. For medium to coarse sands and gravels, however, membrane-compliance effects may have a significant influence on test results. The scope of this paper is threefold: firstly, to review, examine, and evaluate the variety of methods to measure and characterize membrane compliance; secondly, to develop an improved understanding of the factors affecting membrane compliance; and thirdly, to provide an enhanced, updated, and expanded correlation for estimating membrane compliance characteristics as a function of material grain size for a range of soil types, including a wide range of gradation types and representative grain sizes from silts through gravels. Key words : membrane, penetration, compliance, undrained testing, triaxial, measurement, evaluation.

Influence of Grain Size and Grain Boundary of Workpiece on Micro EDM

2014 ◽  
Vol 941-944 ◽  
pp. 2116-2120 ◽  
Author(s):  
Qing Yu Liu ◽  
Qin He Zhang ◽  
Jian Hua Zhang ◽  
Min Zhang
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Micro Edm ◽  
Test Results ◽  
Machining Performance ◽  
Grain Sizes ◽  
Stainless Steel 304 ◽  
Micro Holes ◽  
The Difference ◽  
Micro Features

Micro EDM is used to machine micro features which are of the same size order as material microstructure of workpiece. Due to the difference of the thermal properties between the crystal grain and grain boundary, the machining performance of micro EDM varies with the crystal grain sizes of workpiece. This paper investigated on the influence of grain size and grain boundary on the machining performance of micro EDM. By drilling micro holes on two pieces of stainless steel 304 (SUS 304) which are different in grain sizes, test results revealed that the characteristics of micro EDM is influenced by grain sizes of workpiece materials significantly.

Modulated Hall-Effect Techniques for the Study of Transport Properties of Microcrystalline Silicon with Different Grain Sizes

1996 ◽  
Vol 420 ◽  
Author(s):  
P. Hapke ◽  
U. Backhausen ◽  
R. Carius ◽  
F. Finger ◽  
S. Ray
Keyword(s):  
Grain Size ◽  
Hall Effect ◽  
Transport Properties ◽  
Thermal Emission ◽  
Clear Correlation ◽  
Microcrystalline Silicon ◽  
Grain Sizes ◽  
Wide Range ◽  
Set Up ◽  
A Current

AbstractHighly doped μc-Si:H samples with a wide range of crystalline volume fractions and grain sizes have been investigated by Hall-effect experiments. We present an experimental set-up with a current modulation technique and a 6-pole contact geometry which allows the measurement of the Hall-effect on highly doped μc-Si:H down to 10K. The experimental results exhibit a clear correlation between the mobility μ and the grain size δ. Further, the results show that the transport in μc-Si:H can not be described by thermal emission over grain boundaries alone, additional transport paths, e.g. tunneling processes through the barriers have to be taken into account.

scholarly journals Joining Of Green Body And Dense Substrate For Indium Tin Oxide Under Uniaxial Pressure In An Open Condition

2015 ◽  
Vol 60 (2) ◽  
pp. 1209-1212
Author(s):  
G.-S. Moon ◽  
T.-J. Chung ◽  
S.-H. Yang ◽  
G.-S. Hong ◽  
K.-S. Oh
Keyword(s):  
Grain Size ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Transparent Conducting Oxide ◽  
Theoretical Density ◽  
Uniaxial Pressure ◽  
Green Body ◽  
Grain Sizes ◽  
Transparent Conducting ◽  
The Difference

Abstract The green body and dense substrate of indium tin oxide was joined by uniaxially pressing at 0.3 MPa at 1300°C to test the restoring of the eroded part of transparent conducting oxide target. The green body was sintered to 98% of theoretical density under the suppression of shrinkage along the boundary below 5%. The boundary between two parts was free of pore but could be recognized from the difference in grain sizes. The joined part had the virtually same density with the substrate, but the grain size was less than one fifth compared with that of substrate.

scholarly journals Clinical comparison of the stain removal efficacy of two air polishing powders

2017 ◽  
Vol 11 (03) ◽  
pp. 370-375
Author(s):  
Rosalin Hongsathavij ◽  
Yosvimol Kuphasuk ◽  
Kanyawat Rattanasuwan
Keyword(s):  
Grain Size ◽  
Sodium Bicarbonate ◽  
Patient Comfort ◽  
Patient Acceptance ◽  
Double Blind ◽  
Grain Sizes ◽  
Air Polishing ◽  
Clinical Comparison ◽  
Stain Removal ◽  
The Difference

ABSTRACT Objectives:Air polishing with sodium bicarbonate powders with a grain size of 40 μm is recommended for patient comfort. However, the efficacy of small grain size on stain removal has not been adequately studied. This study aimed to compare the stain removal efficacy of sodium bicarbonatepowders with grain sizes of 65 and 40 μm and to evaluate patient acceptance and operator opinion after using both air polishing powders. Materials and Methods: A double-blind, randomized, split-mouth study was conducted with 35 participants with moderate to heavy dental staining on both sides of the upper teeth. Removal of dental stains on the index teeth was performed using sodium bicarbonate powders with a grain size of either 65 or 40 μm. The time taken to completely remove all dental stains was recorded. After treatment, a questionnaire was used to evaluate patient acceptance and the operator's opinion.Results: The average time for the removal of all stains by powder was 4.5 ± 3.6 min with a grain size of 65 μm and 4.4 ± 3.8 min with a grain size of 40 μm. The difference in the average time between the two groups was not significant (P = 0.461). The operator's opinions of the two powders were identical, and patient acceptance did not differ significantly between the two types of powders.Conclusions: The 40 μm sodium bicarbonate powder removed dental stains as efficiently as the 65-μm powder. Powder handling and patient acceptance were comparable between grain sizes of 65 and 40 μm.

The Effect of Grain Boundaries and Second-Phase Particles on Hydride Precipitation in Zirconium Alloys

MRS Advances ◽  
2018 ◽  
Vol 3 (31) ◽  
pp. 1749-1754 ◽  
Author(s):  
Said El Chamaa ◽  
Mitesh Patel ◽  
Catrin M. Davies ◽  
Mark R. Wenman
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Zirconium Alloys ◽  
Second Phase ◽  
Distribution Profile ◽  
Grain Sizes ◽  
Hydride Precipitation ◽  
Nucleation Sites ◽  
Wide Range ◽  
Pure Zirconium

ABSTRACTUnderstanding the precipitation of brittle hydride phases is crucial in establishing a failure criterion for various zirconium alloy nuclear fuel cladding. Accordingly, it is important to quantify the sensitivity of hydride precipitation to the component microstructure. This experimental investigation focuses on two microstructural characteristics and their role as hydride nucleation sites: The grain size and the alloy chemical composition. Samples of commercially pure zirconium (Zr-702) and Zircaloy-4, each with a wide range of grain sizes, were hydrided to 100 ppm and micrographs of the hydride distribution were optically analyzed for inter-granular and intra-granular precipitate sites. For most grain sizes, it was found that a significantly lower fraction of the precipitated hydrides nucleated at grain boundaries in Zircaloy-4 than in Zr-702, suggesting that a higher SPP content encourages the formation of intra-granular hydrides. Moreover, this effect became more prominent as the grain size increased; large-grain specimens contained a higher fraction of intra-granular hydrides than small-grain specimens of both Zr-702 and Zircaloy-4, highlighting the potency of grain boundaries as nucleation sites and how SPPs can influence the hydride distribution profile.

Comparative Effects of High-Tech Visual Scene Displays and Low-Tech Isolated Picture Symbols on Engagement From Students With Multiple Disabilities

2019 ◽  
Vol 50 (4) ◽  
pp. 693-702 ◽  
Author(s):  
Christine Holyfield ◽  
Sydney Brooks ◽  
Allison Schluterman
Keyword(s):  
Language Learning ◽  
Augmentative And Alternative Communication ◽  
Visual Analysis ◽  
Multiple Disabilities ◽  
Visual Scene ◽  
Future Research ◽  
High Tech ◽  
Single Subject ◽  
Wide Range ◽  
The Difference

Purpose Augmentative and alternative communication (AAC) is an intervention approach that can promote communication and language in children with multiple disabilities who are beginning communicators. While a wide range of AAC technologies are available, little is known about the comparative effects of specific technology options. Given that engagement can be low for beginning communicators with multiple disabilities, the current study provides initial information about the comparative effects of 2 AAC technology options—high-tech visual scene displays (VSDs) and low-tech isolated picture symbols—on engagement. Method Three elementary-age beginning communicators with multiple disabilities participated. The study used a single-subject, alternating treatment design with each technology serving as a condition. Participants interacted with their school speech-language pathologists using each of the 2 technologies across 5 sessions in a block randomized order. Results According to visual analysis and nonoverlap of all pairs calculations, all 3 participants demonstrated more engagement with the high-tech VSDs than the low-tech isolated picture symbols as measured by their seconds of gaze toward each technology option. Despite the difference in engagement observed, there was no clear difference across the 2 conditions in engagement toward the communication partner or use of the AAC. Conclusions Clinicians can consider measuring engagement when evaluating AAC technology options for children with multiple disabilities and should consider evaluating high-tech VSDs as 1 technology option for them. Future research must explore the extent to which differences in engagement to particular AAC technologies result in differences in communication and language learning over time as might be expected.

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