Any finite set of lines in the real projective plane determines a cell complex; these complexes and their combinatorial properties have been a subject of study at least since 1826 [9]. More recently, Levi [6] considered a topological generalization of this notion, defined as follows: Consider a simple closed curve in RP2 which does not separate RP2; this is called a pseudoline. (It is clear tha...

Improving efficiency of hydrogen cooling in cryogenic conditions is important for the wider applications energy systems. The approach investigated this study based on a Ranque-Hilsch vortex tube (RHVT) that generates temperature separation working fluid. simplicity RHVT also valuable characteristic In present work, novel shapes are computationally with goal to raise process. Specifically, smoot...

The Ogee Spillway is one of the most crucial flood control structures, and it developed at same time as dams. Spillway's downstream portions experience scouring due to flow, a problem that persists in reality. This paper aims investigate hydraulic performance stepped block dissipater using three-dimensional simulation model. dissipated was given new distribution may be one, two, or three rows t...

Introduction: Natural materials are more efficient and attractive than synthetic materials. In this study, the sound absorption behavior by natural kenaf composite and Micro-Perforated Panel (MPP) at low and medium frequency region was investigated. Material and Methods: Initially, the results of kenaf fibers with a thickness of 10 mm were validated by the Finite Element Method (FEM) based on ...

We introduce a new combinatorial object, the double-permutation sequence, and use it to encode a family of mutually disjoint compact convex sets in the plane in a way that captures many of its combinatorial properties. We use this encoding to give a new proof of the Edelsbrunner-Sharir theorem that a collection of n compact convex sets in the plane cannot be met by straight lines in more than 2...

On the basis of perodic density functional theory (DFT) calculations, we have addressed the geometric structures and electronic properties of water layers on flat and stepped Pb surfaces. In contrast to late d-band metals, on Pb(111) the energy minimum structure does not correspond to an ice-like hexagonal arrangement at a coverage of 2/3, but rather to a distorted structure at a coverage of 1 ...

Although the pressure chamber has gained wide acceptance as a convenient method for the measurement of plant water status, the relationship between the pressure observed in the chamber and other parameters of plant water status remains unclear. If one assumes that the spatial arrangement of water in the shoot is the same under pressure as it was in the intact plant, the positive pressure (P) an...

Two dimensional optical fiber measurement system is used to investigate experimentally the arc motion and reignition with four different configurations of quenching chamber in an AC contactor. It demonstrates that the splitter plate arrangement has significant effect on the arc motion in arc quenching chamber, and fixing arc runner in the first and last splitter plates benefits to arc motion, a...

This paper presents a parametric study of steel I- beam with stepped flanges by using finite element analysis. Stepped flange beam is used in structures to decrease the negative bending moments near interior supports that causes failure due to buckling. Steps in the cross section can be achieved by adding cover plates to the beam flanges, changing the size of the hot rolled section, or changing...

We use a regular arrangement of kirigami elements to demonstrate an inverse design paradigm for folding a flat surface into complex target configurations. We first present a scheme using arrays of disclination defect pairs on the dual to the honeycomb lattice; by arranging these defect pairs properly with respect to each other and choosing an appropriate fold pattern a target stepped surface ca...