Investigation of Defect InP(001) Surface by Low Energy Ion Scаttering Spectroscopy

In this paper presents the computer simulation results on the investigations of the ion scattering processe on the defect InP(001)<110>,<ī10> surface under low-energy grazing ion bombardment have been presented. The peculiarities trajectories of the scattered ions from surface defect, atomic chain and semichannel have been investigated by computer simulation. It was found some trajectories nearby surface atomic chain which have loop shape and a line form. At grazing ion incidence, from a correlation of the experimental and calculated energy distributions of the scattered particles, one may determine a spatial extension of the missing atom on the monocrystal surface damaged by the ion bombardment.

Geometry effects in topologically confined bilayer graphene loops

We investigate the electronic confinement in bilayer graphene by topological loops of different shapes. These loops are created by lateral gates acting via gap inversion on the two graphene sheets. For large-area loops the spectrum is well described by a quantization rule depending only on the loop perimeter. For small sizes, the spectrum depends on the loop shape. We find that zero-energy states exhibit a characteristic pattern that strongly depends on the spatial symmetry. We show this by considering loops of higher to lower symmetry (circle, square, rectangle and irregular polygon). Interestingly, magnetic field causes valley splittings of the states, an asymmetry between energy reversal states, flux periodicities and the emergence of persistent currents.

Construindo o laço do planeta marte em relação às estrelas distantes no sistema copernicano

O presente trabalho visa apresentar uma proposta de construção aproximada do movimento de Marte, que gera para um observador na Terra um formato de laço em relação às estrelas distantes na perspectiva do sistema copernicano. Para tal, utilizaremos o conhecido software GeoGebra. Crescendo consideravelmente, o software está sempre sendo atualizado e chega a reunir fóruns e grupos, contando em sua plataforma com uma gigantesca variedade de atividades para a matemática e a ciência. Dentre as muitas possibilidades, o modelo que escolhemos nos gerará um cenário para se pensar sobre a história das ideias envolvidas. Acreditamos que por intermédio de trabalhos deste tipo é possível promover uma discussão mais ampla e interdisciplinar sobre os conceitos que utilizamos, indo além dos brevíssimos recortes apresentados em livros didáticos. The present work aims to present a proposal for an approximate construction of the Mars movement, which generates for an observer on Earth a loop shape in relation to distant stars in the perspective of the Copernican system. For this, we will use the well-known GeoGebra software. Growing considerably, the software is always being updated and comes to gather forums and groups, counting on its platform a huge variety of activities for mathematics and science. Among the many possibilities, the model we choose will provide us with a scenario to think about the history of the ideas involved. We believe that through works of this type it is possible to promote a broader and interdisciplinary discussion on the concepts we use, going beyond the very brief cutouts presented in textbooks.

Calculation of interlock, 1 × 1 rib, and single jersey knitted fabrics shrinkage during the dyeing process after determining loop shape

This study investigated existing dimensional variations in knitted fabrics produced by weft-knitting technology for knitting and dry relaxation, dyed and dry relaxation, and dyed and wash relaxation for the interlock, 1 × 1 rib, and single jersey structures. This paper demonstrates that once the structure has been knitted, the shape that the loop takes in the fabric, and loop length and loop width, for each relaxation state will be the main factor responsible for dimensional variations in cotton knitted fabrics. It also shows how loop length affects knitted fabric dimensions when knitting machine parameters are modified by varying the use of feeders, and obtaining more loosely or more tightly knitted fabrics. In this study a model to predict the longitudinal and transversal shrinkage of interlock, 1 × 1 rib, and single jersey fabrics after the dyeing process is presented. This avoids following the conventional analysis procedure according to Standard UNE-EN ISO 6330 of September 2012 and, thus, avoids investing relatively long calculation times, which speeds up the production process by avoiding product lots being stopped. These results are important for textile industry technicians as they substantially simplify production calculations in weft-knitted fabrics companies. This work offers an effective method for predicting the longitudinal and transversal shrinkage and width of knitting fabrics after the dyeing process from the loop dimension after the knitting process. The application of the study results may help businesses to significantly save time and, consequently, imply an intermediate product stock investment saving.

Right ventricular pressure-volume loop shape and systolic pressure change in pulmonary hypertension

Right ventricular (RV) function determines outcome in pulmonary arterial hypertension (PAH). RV pressure-volume loops - the gold standard for measuring RV function - are difficult to analyze. Our aim was to investigate whether simple assessments of RV pressure-volume loop morphology and RV systolic pressure differential reflect PAH severity and RV function. We analyzed multi-beat RV pressure-volume loops (obtained by conductance catheterization with preload reduction) in 77 patients with PAH and 15 patients without pulmonary hypertension in two centers. Patients were categorized according to their pressure-volume loop shape (triangular, quadratic, trapezoid, or notched). RV systolic pressure differential was defined as end-systolic minus beginning-systolic pressure (ESP−BSP); augmentation index as ESP−BSP/pulse pressure; pulmonary arterial capacitance (PAC) as stroke volume/pulse pressure; and RV-arterial coupling as end-systolic/arterial elastance (Ees/Ea). Trapezoid and notched pressure-volume loops were associated with the highest afterload (Ea), augmentation index, pulmonary vascular resistance (PVR), mean pulmonary arterial pressure, stroke work, and B-type natriuretic peptide, and the lowest Ees/Ea and PAC. Multivariate linear regression identified Ea, PVR, and stroke work as the main determinants of ESP−BSP. ESP−BSP also significantly correlated with multi-beat Ees/Ea (Spearman's rho: −0.518, P < 0.001). A separate retrospective analysis of 113 patients with PAH showed that ESP−BSP obtained by routine right heart catheterization significantly correlated with a non-invasive surrogate of RV-arterial coupling (tricuspid annular plane systolic excursion/pulmonary arterial systolic pressure ratio; rho: −0.376, P < 0.001). In conclusion, pressure-volume loop shape and RV systolic pressure differential predominately depend on afterload and PAH severity and reflect RV-arterial coupling in PAH.

Investigation of Mechanical Strains in Thermal Compensation Loop of Superconducting NbTi Cable during Bending and Cyclic Operation

In the paper, the thermal compensation loops on a composite, superconducting NbTi cable were investigated. This type of cable is used in the superconducting, fast ramping magnets of the SIS100 synchrotron, part of the Facility for Antiproton and Ion Research (FAIR) under construction in Darmstadt, Germany. The influence of space restrictions and electromagnetic cross-talk on the design of the thermal compensation loop was discussed. Plastic deformation of cable components during bending was analyzed by numerical simulations and experiments. A three-dimensional numerical model of the cable was prepared with individual superconducting wires in contact with a central cooling pipe. The bending of a straight cable into a compensation loop shape was simulated, followed by cyclic operation of the cable during thermal cycles. The maximum strains in the superconducting strands and cooling tube were analyzed and discussed.

Experimental study of loop shape using 0.025-inch ERCP guidewires (with videos)

Background and study aims Duct penetration by the guidewire sometimes occurs during endoscopic retrograde cholangiography, which might lead to adverse events such as acute pancreatitis. To prevent duct penetration, making a loop shape with the guidewire might provide a useful technique. The aim of this experimental study was thus to evaluate which types of guidewire can most easily form a loop shape. Methods This experimental study evaluated six guidewires (0.025-inch, angle type): MICHISUJI; VisiGlide 2; Jagwire; Pathcorse; RevoWave-α UltraHard 2; and M-through. Flexibility of the tip, shaft stiffness, and the ability to form a loop were evaluated for each type in an ex vivo model. Deformation behavior was also recorded on video, and factors suitable for making a loop shape in each guidewire were evaluated. Results Flexibility and stiffness of each guidewire differed significantly. During an experimental study regrading deformation behavior before forming a loop shape, maximum load was lower for MICHISUJI (6.8 g) than for other guidewires (Jagwire [11.3 g], M-through [12.9 g], VisiGlide 2 [12.9 g], Revowave [21 g], and Pathcorse [25.4 g]). Mean time required to achieve a loop shape was as follows: MICHISUJI, 6.2 seconds; M-through, 8.7 seconds; VisiGlide 2, 11.0 seconds; and Revowave, 7.1 seconds. Conclusion In conclusion, characteristics of flexibility and stiffness among guidewires were significantly different in the ex-vivo study. In the experimental study regrading deformation behavior until achieving a loop shape, maximum load also differed. To evaluate whether guidewires easily form a loop shape, clinical study is needed.

Right Knee—The Weakest Point of the Best Ultramarathon Runners of the World? A Case Study

The impact of ultramarathons (UM) on the organs, especially in professional athletes, is poorly understood. We tested a 36-year-old UM male runner before and after winning a 24-h marathon. The primary goal of the study was cardiovascular assessment. The athlete experienced right knee pain for the first time after 12 h of running (approximately 130 km), which intensified, affecting his performance. The competitors ran on a 1984 m rectangle-loop (950 × 42 m) in an atypical clockwise fashion. The winner completed 516 rectangular corners. Right knee Magnetic Resonance Imaging (MRI) one day after the run showed general overload in addition to degenerative as well as specific features associated with “turning to the right”. Re-examination after three years revealed none of these findings. Different kinds of overloading of the right lower limb, including right knee pain, were indicated in 6 of 10 competitors from the top 20, including a woman who set the world record. The affected competitors suggested as cause for discomfort the shape of the loop and running direction. They believed that changing the direction of the run during the competition and an athletics stadium loop shape on a 2000–2500 m length is better for 24-h UM runners. In the absence of technical alternatives, the “necessary evil” is a counterclockwise run (also Association of Athletics Federations IAAF recommendation). Results suggest that a one-way, clockwise, 24-h UM run had an adverse effect on the athlete’s right knee, as a result of unsymmetrical load. Organizers of 24-h UM runs should consider the shape of the competition loop and apply the principle of uniform load on the musculoskeletal system (alternate directions run). In case of technical impossibility, it would be better to run counterclockwise, which is more common, preferred by runners, and recommended by the IAAF.