Investigation of Physical and Mechanical Characteristics of Rubber Materials Exposed to High-Pressure Hydrogen.

Rubber materials play a key role in preventing hydrogen gas leakage in high-pressure hydrogen facilities. Therefore, it is necessary to investigate rubber materials exposed to high-pressure hydrogen to ensure operational safety. In this study, permeation, volume swelling, hydrogen content, and mechanical characteristics of acrylonitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluorocarbon (FKM) samples exposed to pressures of 35 and 70 MPa were investigated.

Characterizing the Diffusion Property of Hydrogen Sorption and Desorption Processes in Several Spherical-Shaped Polymers.

We developed a method for characterizing permeation parameters in hydrogen sorption and desorption processes in polymers using the volumetric measurement technique. The technique was utilized for three polymers: nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), and fluoroelastomer (FKM). The total uptake (C∞), total desorbed content (C0), diffusivity in sorption (D), and diffusivity in desorption (D) of hydrogen in the polymers were determined versus the sample diameter used in both processes.

Characterization technique of gases permeation properties in polymers: H, He, N and Ar gas.

We demonstrate a simple experimental technology for characterizing the gas permeation properties of H, He, N and Ar absorbed in polymers. This is based on the volumetric measurement of released gas and an upgraded diffusion analysis program after high-pressure exposure. Three channel measurements of sorption content of gases emitted from polymers after decompression are simultaneously conducted, and then, the gas uptake/diffusivity as a function of exposed pressure are determined in nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM) rubbers, low-density polyethylene (LDPE) and high-density polyethylene (HDPE), which are used for gas sealing materials under high pressure.

Volume Dependence of Hydrogen Diffusion for Sorption and Desorption Processes in Cylindrical-Shaped Polymers.

In the actual application of gas transport properties under high pressure, the important factors are sample size dependence and permeation efficiency, related to gas sorption. With a modified volumetric analysis technique, we firstly measured the overall diffusion properties and equilibrium times for reaching the saturation of hydrogen content in both hydrogen sorption and desorption processes. The measured parameters of total uptake (), total desorbed content (), diffusion coefficient in sorption (), diffusion coefficient in desorption (), sorption equilibrium time () and desorption equilibrium time () of hydrogen in two polymers were determined relative to the diameter and thickness of the cylindrical-shaped polymers in the two processes.

Hydrogen Sensing Using Paper Sensors with Pencil Marks Decorated with Palladium.

Paper-based sensors fabricated using the pencil-on-paper method are expected to find wide usage in many fields owing to their low cost and high reproducibility. Here, hydrogen (H) detection was realized by applying palladium (Pd) nanoparticles (NPs) to electronic circuits printed on paper using a metal mask and a pencil. We confirmed that multilayered graphene was produced by the pencil, and then characterized Pd NPs were added to the pencil marks.

Real-Time Monitoring of a Botulinum Neurotoxin Using All-Carbon Nanotube-Based Field-Effect Transistor Devices.

The possibility of exposure to botulinum neurotoxin (BoNT), a powerful and potential bioterrorism agent, is considered to be ever increasing. The current gold-standard assay, live-mouse lethality, exhibits high sensitivity but has limitations including long assay times, whereas other assays evince rapidity but lack factors such as real-time monitoring or portability. In this study, we aimed to devise a novel detection system that could detect BoNT at below-nanomolar concentrations in the form of a stretchable biosensor.

Mechanical test method and properties of a carbon nanomaterial with a high aspect ratio.

Superior nanomaterials have been developed and applied to many fields, and improved characteristic of nanomaterials have been studied. Measurement of the mechanical properties for nanomaterials is important to ensure the reliability and predict the service life times of products containing nanomaterials. However, it is challenging to measure the mechanical properties of nanomaterials due to their very small dimensions.

Unzipped Nanotube Sheet Films Converted from Spun Multi-Walled Carbon Nanotubes by O2 Plasma.

Large-scale graphene or carbon nanotube (CNT) films are good candidates for transparent flexible electrodes, and the strong interest in graphene and CNT films has motivated the scalable production of a good-conductivity and an optically transmitting film. Unzipping techniques for converting CNTs to graphene are especially worthy of notice. Here, we performed nanotube unzipping of the spun multi-walled carbon nanotubes (MWCNTs) to produce networked graphene nanoribbon (GNR) sheet films using an 02 plasma etching method, after which we produced the spun MWCNT film by continually pulling MWCNTs down from the vertical well aligned MWCNTs on the substrate.

The Mechanical and Electrical Properties of a Single Carbon Nanofiber Induced by Applying Tensile Strain.

Carbon nanofibers (CNFs) are good candidates for nano-system applications because they have the excellent mechanical and the electrical properties. The mechanical and electrical properties of a single CNF were measured. A tensile test and a measurement of the electrical resistance of CNFs during elongation were performed inside a scanning electron microscope.

Biomedical applications of holographic microspectroscopy [invited].

The identification and quantification of specific molecules are crucial for studying the pathophysiology of cells, tissues, and organs as well as diagnosis and treatment of diseases. Recent advances in holographic microspectroscopy, based on quantitative phase imaging or optical coherence tomography techniques, show promise for label-free noninvasive optical detection and quantification of specific molecules in living cells and tissues (e.g.

Revisiting whitlockite, the second most abundant biomineral in bone: nanocrystal synthesis in physiologically relevant conditions and biocompatibility evaluation.

The synthesis of pure whitlockite (WH: Ca18Mg2(HPO4)2(PO4)12) has remained a challenge even though it is the second most abundant inorganic in living bone. Although a few reports about the precipitation of WH in heterogeneous phases have been published, to date, synthesizing WH without utilizing any effects of a buffer or various other ions remains difficult. Thus, the related research fields have encountered difficulties and have not been fully developed.

Apocynin regulates cytokine production of CD8(+) T cells.

Apocynin is known to suppress the production of reactive oxygen species (ROS) by inhibiting NADPH oxidases, specifically phagocytic NADPH oxidase (PHOX or NOX2). Given the pro-inflammatory effects of ROS, apocynin has been studied extensively for its use as a therapeutic agent in various disease models. While the effects of apocynin on neutrophils and monocytes have been investigated, it remains to be elucidated whether apocynin modulates the effector function of T cells.

Growth of spin-capable multi-walled carbon nanotubes and flexible transparent sheet films.

Iron-catalyzed spin-capable multi-walled carbon nanotubes (MWCNTs) were grown on a SiO2 wafer by chemical vapor deposition, which was carried out at 780 degrees C using C2H2 and H2 gases. We fabricated a flexible transparent film using the spun MWCNTs. The MWCNT sheets were produced by being continuously pulled out from well-aligned MWCNTs grown on a substrate.

The mechanical properties and test of a single ZnO nanorod inside scanning electron microscopy.

The bending and tensile tests of the ZnO nanorods were carried out by controlling a force sensor and a nano-manipulator inside a scanning electron microscope (SEM). The force sensor was mounted on the nano-manipulator, was controlled with the nano-manipulate. The load response during the mechanical test for the ZnO nanorod was obtained by using the force sensor which is formed as a cantilever.

The effect of two neighboring defects on the mechanical properties of carbon nanotubes.

The tensile behavior of single-walled nanotubes (SWNTs) having two defects (vacancy or Stone-Wales) positioned next to each other was simulated in this study to investigate the influence of the spatial arrangement of defects on the mechanical properties. The simulations were performed using classical molecular dynamics (MD) at the atomic scale. Two neighboring vacancy defects reduced the failure strength as much as 46% and the failure strain as much as 80% in comparison with those of pristine SWNTs, while two neighboring Stone-Wales defects reduced them as much as 34% and 70% respectively.

Combined structural refinement of Bi3.5La0.5Ti3O12 using neutron and X-ray powder diffraction data.

A combined structural refinement of Bi3.5La0.5Ti3O12 against both neutron and X-ray diffraction data was performed at 298 K on the basis of the Raman study.

A nondestructive method for estimation of the fracture toughness of CrMoV rotor steels based on ultrasonic nonlinearity.

The objective of this paper is to develop a nondestructive method for estimating the fracture toughness (K(IC)) of CrMoV steels used as the rotor material of steam turbines in power plants. To achieve this objective, a number of CrMoV steel samples were heat-treated, and the fracture appearance transition temperature (FATT) was determined as a function of aging time. Nonlinear ultrasonics was employed as the theoretical basis to explain the harmonic generation in a damaged material, and the nonlinearity parameter of the second harmonic wave was the experimental measure used to be correlated to the fracture toughness of the rotor steel.