A New Paradigm Unifying the Concepts in Particle Abrasion and Breakage

This study introduces a new paradigm that unifies abrasion and breakage concepts, allowing for a holistic understanding of the comminution process. The significance of this paradigm lies in its ability to present both abrasion and breakage in a single big picture because both processes can co-occur under loading as particles are subjected to friction as well as collision. A comprehensive descriptive framework is employed to this end, which operates in a log-transformed surface-area-to-volume ratio ($A/V$) and volume ($V$) space. This space facilitates a holistic characterization of the four-dimensional particle geometry features, i.e., volume ($V$), surface area ($A$), size ($D$), and shape (${\beta}$). Consequently, this approach enables to systematically relate the co-occurring abrasion and breakage process to co-evolving particle shape and size. Transformative concepts including the breakage line, sphere line, and average shape-conserving line are introduced to describe the limit states and a special comminution process. This approach also uncovers a self-similar nature in evolving particle geometry during comminution, which will be a significant discovery for the granular materials research community given the most fundamental properties observed in natural phenomena.Comment: 10 pages, 5 figures; No difference from arXiv:2306.04635v1 except the first page stam

Growth of ultra-uniform graphene using a Ni/W bilayer metal catalyst

We investigated a bilayer catalyst system consisting of polycrystalline Ni and W films for growing mono-layer graphene over large areas. Highly uniform graphene was grown on Ni/W bilayer film with 100% coverage. The graphene grown on Ni/W bilayer film and transferred onto an insulating substrate exhibited average hole and electron mobilities of 727 and 340 cm(2)V(-1)s(-1), respectively. A probable growth mechanism is proposed based on X-ray diffractometry and transmission electron microscopy, which suggests that the reaction between diffused carbon and tungsten atoms results in formation of tungsten carbides. This reaction allows the control of carbon precipitation and prevents the growth of non-uniform multilayer graphene on the Ni surface; this has not been straightforwardly achieved before. These results could be of importance in better understanding mono-layer graphene growth, and suggest a facile fabrication route for electronic applications. (C) 2015 AIP Publishing LLCopen0

Reinforcing effects of methamphetamine in an animal model of Attention-Deficit/Hyperactivity Disorder-the Spontaneously Hypertensive Rat

Substrains of the Spontaneously Hypertensive rat (SHR), a putative animal model of Attention-Deficit/Hyperactivity Disorder (ADHD), have demonstrated increased sensitivity to many drugs of abuse, including psychostimulants. Therefore, it was suggested that studies in SHR may help elucidate ADHD and comorbidity with substance use disorder (SUD). However, the drug intake profile of the SHR in the most relevant animal model of drug addiction, the self-administration (SA) test, and its response on the conditioned place preference (CPP) paradigm are not yet determined. In the present study, we employed SA and CPP tests to investigate the reinforcing effects of the psychostimulant methamphetamine in an SHR substrain obtained from Charles River, Japan (SHR/NCrlCrlj). Concurrent tests were also performed in Wistar rats, the strain representing "normal" heterogeneous population. To address if the presence of ADHD behaviors further increases sensitivity to the rewarding effect of methamphetamine during adolescence, a critical period for the onset of drug abuse, CPP tests were especially conducted in adolescent Wistar and SHR/NCrlCrlj. We found that the SHR/NCrlCrlj also acquired methamphetamine SA and CPP, indicating reinforcing effects of methamphetamine in this ADHD animal model. However, we did not observe increased responsiveness of the SHR/NCrlCrlj to methamphetamine in both SA and CPP assays. This indicates that the reinforcing effects of methamphetamine may be similar in strains and that the SHR/NCrlCrlj may not adequately model ADHD and increased sensitivity to methamphetamine

GAIT ASYMMETRY IN CHILDREN WITH DOWN SYNDROME

It has been reported that approximately 80% of children with Down syndrome (OS) exhibit gait problems (Matteo, 2002), characterized by flat-footed contact with no heel-strike, excessive abduction of the leg in the swing phase, and abnormal knee and hip f1exions throughout the gait cycle (Parker et aI., 1986). Due to muscle hypotonia, muscle weakness, !igamentous laXity, and other orthopedic abnormalities, different gait characteristics exist. The purpose of this study was to investigate the gait (walking and running) asymmetry in children with OS