9,982 research outputs found
A Comparative Analysis of Hydrogen Storage Characteristics in AZ31 Magnesium Alloy with the Addition of Graphene and Carbon Nanotubes via Ball Milling Process
In the present investigation, an examination was conducted on the hydrogen storage performance of industrial waste grade AZ31 magnesium alloy when combined with either Carbon Nanotubes or Graphene. This study aims to understand the enhancement of hydrogen storage properties reinforced with polymer materials, such as Graphene or Carbon Nanotubes. The experimental samples, composed of AZ31 Magnesium Alloy combined with either Carbon Nanotubes or Graphene, were crafted through gravity casting. Thereafter, a high-energy ball milling process was employed to further refine the hydrogen storage material powders. The micrographic structures of all the sample powders were analyzed by x-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Additionally, the average particle size distributions of the sample powders were quantified for comprehensive characterization. The absorbed and desorbed hydrogen capacity and kinetics was calculated by a Sievert's type apparatus. Overall, the performance of the sample powder AZ31-0.1G showed the highest absorption and desorption at a rate of 0.0036 wt%/s and 0.0084 wt%/s. Moreover, the hydrogen capacity of AZ31-0.1G reached the highest value at 5.32 wt%. The acquired data unveils that with the adding of either Graphene or Carbon Nanotubes as additives significantly improved the hydrogen storage capacity of AZ31 magnesium alloy
Probing WIMPs in space-based gravitational wave experiments
Although searches for dark matter have lasted for decades, no convincing
signal has been found without ambiguity in underground detections, cosmic ray
observations, and collider experiments. We show by example that gravitational
wave (GW) observations can be a supplement to dark matter detections if the
production of dark matter follows a strong first-order cosmological phase
transition. We explore this possibility in a complex singlet extension of the
standard model with CP symmetry. We demonstrate three benchmarks in which the
GW signals from the first-order phase transition are loud enough for future
space-based GW observations, for example, BBO, U-DECIGO, LISA, Taiji, and
TianQin. While satisfying the constraints from the XENON1T experiment and the
Fermi-LAT gamma-ray observations, the dark matter candidate with its mass
around ~TeV in these scenarios has a correct relic abundance obtained
by the Planck observations of the cosmic microwave background radiation.Comment: 11 pages, 2 figures, 2 table
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