Tabular Two-Dimensional Correlation Analysis for Multifaceted Characterization Data

We propose tabular two-dimensional correlation analysis for extracting features from multifaceted characterization data, essential for understanding material properties. This method visualizes similarities and phase lags in structural parameter changes through heatmaps, combining hierarchical clustering and asynchronous correlations. We applied the proposed method to datasets of carbon nanotube (CNTs) films annealed at various temperatures and revealed the complexity of their hierarchical structures, which include elements like voids, bundles, and amorphous carbon. Our analysis addresses the challenge of attempting to understand the sequence of structural changes, especially in multifaceted characterization data where 11 structural parameters derived from 8 characterization methods interact with complex behavior. The results show how phase lags (asynchronous changes from stimuli) and parameter similarities can illuminate the sequence of structural changes in materials, providing insights into phenomena like the removal of amorphous carbon and graphitization in annealed CNTs. This approach is beneficial even with limited data and holds promise for a wide range of material analyses, demonstrating its potential in elucidating complex material behaviors and properties.Comment: 15 pages, 4 figure

Very high-cycle fatigue properties of 90° unidirectional CFRP laminates and evaluation of fatigue limits by free volume measurement using positron microscopy

The objective of this study was to experimentally evaluate the fatigue limit of 90° unidirectional carbon fiber reinforced plastic (CFRP) laminates. The very high-cycle fatigue properties of the specimens were evaluated using ultrasonic and electromagnetic fatigue testing machines. Ultrasonic fatigue tests were conducted to obtain the fatigue properties under the giga-cycle regime. The specimen geometry was designed to resonate at 20 kHz, the specimen consisted of CFRP laminate and a metal tab to connect to the horn end of the testing machine. Additionally, the free volume of the matrix material, namely, epoxy resin, of the CFRP laminates was evaluated using the positron annihilation method. A slit was introduced in the specimen surface to identify the location of damage development, which facilitated the free volume measurement by positron microscopy. The obtained S-N curves reveal that failure did not occur at strain levels lower than εmax = 0.75% at the slit tip for all specimens up to N = 1.0 × 109 cycles. The free volume measurement for a specimen set above the threshold strain level revealed that the free volume increased in size and decreased in amount as the number of cycles increased. The test results revealed that the opposite trend existed below the threshold, which suggests that a fatigue limit may exist

Transport of small and neutral solutes through reverse osmosis membranes: Role of skin layer conformation of the polyamide film

The polyamide skin layer of reverse osmosis (RO) membranes was characterised using advanced and complementary analytical techniques to investigate the mechanisms underlying the permeation of contaminants of emerging concern in potable water reuse ? N-nitrosodimethylamine (NDMA) and N-nitrosomethylethylamine (NMEA). This study used five RO membrane samples with similar membrane properties. The five RO membrane samples spanned over a large range of water permeance (0.9?5.8 L/m2 h bar) as well as permeation of NDMA (9?66%) and NMEA (3?29%). Despite these differences among the five RO membranes, characterisations of the skin layer using positron annihilation lifetime spectroscopy, atomic force microscopy and field emission scanning electron microscopy revealed almost no variation in their free-volume hole-radius (0.270?0.275 nm), effective surface area (198?212%) and thickness (30?35 nm) of the skin layer. The results suggest that there could be other RO skin layer properties, such as the interconnectivity of the protuberances within the polyamide skin layer additional to the free-volume hole-size and thickness of the skin layer, which can also govern water and solute permeation

Newly constructed compact accelerator-based neutron facility at AIST

We have constructed a compact accelerator-based neutron facility at the National Institute of Advanced Industrial Science and Technology (AIST) in Japan aiming at development of structural materials of transportation vehicles for weight reduction. The facility consists of electron linear accelerator, neutron source, and a neutron beamline with a measurement hutch. Currently we are commissioning the accelerator and expecting a first neutron beam in 2019

Newly constructed compact accelerator-based neutron facility at AIST

We have constructed a compact accelerator-based neutron facility at the National Institute of Advanced Industrial Science and Technology (AIST) in Japan aiming at development of structural materials of transportation vehicles for weight reduction. The facility consists of electron linear accelerator, neutron source, and a neutron beamline with a measurement hutch. Currently we are commissioning the accelerator and expecting a first neutron beam in 2019

Synthesis of antihydrogen atoms in a CUSP trap

ASACUSA collaboration has been making a path to realize high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atom in flight for stringent test of the CPT symmetry. Recently, we have succeeded in synthesizing our first cold antihydrogen atoms employing a CUSP trap. It is expected that synthesized antihydrogen atoms in the low-field-seeking states are preferentially focused along the cusp magnetic field axis whereas those in the high-field-seeking states are not focused, resulting in the formation of a spin-polarized antihydrogen beam. We report the recent results of antihydrogen atom synthesis and beam production developed with the CUSP trap. \ua9 2012 Springer Science+Business Media B.V