it is generally recognised that ‘zero’ as we understand the concept today originated in two geographically separated cultures: the maya and indian. however, if zero merely signified a magnitude or a direction separator (i.e. separating those above the zero level from those below the zero level), the egyptian zero, nfr, dating back at least four thousand years, amply served these purposes. if ze...

The use of micromobility (MM), a form sustainable urban mobility which has expected effects such as reducing traffic congestion and greenhouse gases, been rapidly increasing across the world. However, this growth resulted in considerable number MM-related accidents. Most previous studies have explored MM user injuries to improve safety users, but threat pedestrians by is not yet fully understoo...

In this study, nanoscale zero-valent copper (nZVC) as catalyst activated persulfate (PS) was used for the degradation of p-chlorophenol (p-CP) under ultrasonic (US) irradiation in aqueous solution. The effect of different operational parameters such as solution pH (3.5-10.5), PS concentration (1-7.5 mm/L), nZVC dosage (5-35 mg/L) and initial p-CP concentration (10-100 mg/L) were evaluated at di...

for an arbitrary ring $r$, the zero-divisor graph of $r$, denoted by $gamma (r)$, is an undirected simple graph that its vertices are all nonzero zero-divisors of $r$ in which any two vertices $x$ and $y$ are adjacent if and only if either $xy=0$ or $yx=0$. it is well-known that for any commutative ring $r$, $gamma (r) cong gamma (t(r))$ where $t(r)$ is the (total) quotient ring of $r$. in this...