Search results for " ferro"

Comparing Performances of Turbo-roundabouts and Double-lane Roundabouts

2012

Starting from assumptions regarding the arrival process of circulating streams and according to models based on the gap-acceptance theory, the paper is aimed at comparing operational performances between basic turbo-roundabouts and double-lane roundabouts. The paper proposes applications of the Hagring model for entry capacity estimations at double-lane roundabouts and turbo-roundabouts, these latter, in particular, featured by movements with only one or two conflicting traffic streams. This model allows to use, in fact, a bunched exponential distribution to quantify the distribution of major vehicle headways; it also considers specific values different by each lane for behavioural paramete…

La cultura delle vie di trasporto.

2010

Notiziario della SIIV su Le Strade N.1454, Gennaio/Febbraio 2010 (casa Ed. la fiaccola,Milano)-ISSN: 0373-2916.

ALTA FORMAZIONE ALLA RICERCA. A BRESCIA DAL 5 AL 9 SETTEMBRE, LA NONA EDIZIONE DELLA SCUOLA ESTIVA SIIV

2011

Pagina associativa della Società Italiana di Infrastrutture Viarie sulla rivista Le Strade vol.9 N. 1470 anno CXIII (casa Ed. la fiaccola, Milano)-ISSN: 0373-2916, PAG. 158

A scuola di grandi infrastrutture

2011

Pagina associativa della Società Italiana di Infrastrutture Viarie sulla rivista Le Strade vol.10 N. 1471 anno CXIII (casa Ed. la fiaccola,Milano)-ISSN: 0373-2916, PAG. 127

Mn, Fe, Zn and As speciation in a fast-growing ferromanganese marine nodule

2004

The speciation of Mn, Fe, As and Zn in a fast-growing (0.02mm/yr), shallow-marine ferromanganese nodule has been examined by micro X-ray fluorescence, micro X-ray diffraction, and micro X-ray absorption spectroscopy. This nodule exhibits alternating Fe-rich and Mn-rich layers reflecting redox variations in water chemistry. Fe occurs as two-line ferrihydrite. The As is strictly associated with Fe and is mostly pentavalent, with an environment similar to that of As sorbed on or coprecipitated with synthetic ferrihydrite. The Mn is in the form of turbostratic birnessite with ~;10 percent trivalent manganese in the layers and probably ~;8 percent corner-sharing metal octahedra in the interlayer…

Traffic simulation models calibration using speed–density relationship: An automated procedure based on genetic algorithm

2016

Calibration of traffic models.Calibration as optimization problem.Use of genetic algorithm. This paper presents the first results of a research which applied a genetic algorithm to calibrate a microscopic traffic simulation model based on speed-density relationships. A large set of traffic data collected from the A22 Freeway, Italy, was used and a comparison was performed between the field measurements and the simulation outputs obtained for a test freeway segment by using the Aimsun microscopic simulator.The calibration was formulated as an optimization problem to be solved based on a genetic algorithm; the objective function was defined in order to minimize the differences between the sim…

A PSO algorithm for designing 3d highway alignments adopting polynomial solutions

2017

Intelligent optimization algorithms for highway alignments have produced good results so far. However, considering the numerous constraints and factors directly implied in the infrastructure design, the researchers' efforts usually focus only on simplifying the alignment choice, supporting engineers in the design phase. Implementing strategic considerations regarding comfort and safety would be also very important. In this paper, the authors propose a method for designing improved 3D highway alignments using a specific optimization algorithm, based on a Swarm Intelligence technique, adopting an innovative polynomial transition curve as the unique horizontal curvature element, called PPC (Po…

Stima dei costi della sicurezza nei cantieri: ancora troppe incertezze

2009

Estimation of Passenger Car Equivalents for single-lane roundabouts using a microsimulation-based procedure

2017

Calibration of microscopic traffic simulation models for single-lane roundabouts.Use of a meta-analytical estimation of critical and follow up headways.Use of a genetic algorithm-based procedure.Calculation of passenger car equivalents for single-lane roundabouts. Passenger car equivalents for heavy vehicles are required to carry out capacity calculations and perform operational analysis of any road entity (roadway segments or intersections). At single-lane roundabouts, the constraints to the vehicular trajectories imposed by the curvilinear geometric design and the driver's gap acceptance behaviour are expected to produce an impact of the heavy vehicles on the quality of traffic flow diffe…

Comparative enantioseparation of planar chiral ferrocenes on polysaccharide‐based chiral stationary phases

2022

Planar chiral ferrocenes are well-known compounds that have attracted interest for application in synthesis, catalysis, material science, and medicinal chemistry for several decades. In spite of the fact that asymmetric synthesis procedures for obtaining enantiomerically enriched ferrocenes are available, sometimes, the accessible enantiomeric excess of the chiral products is unsatisfactory. In such cases and for resolution of racemic planar chiral ferrocenes, enantioselective high-performance liquid chromatography (HPLC) on polysaccharide-based chiral stationary phases (CSPs) has been used in quite a few literature articles. However, although moderate/high enantioselectivities have been ob…