Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Control theory. The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

Adequacy of lumped parameter models for SCR reactors with monolith structure

Abstract: Two-and one-dimensional steady-state isothermal mathematical models of monolith reactors for selective catalytic reduction (SCR) of NOx by NH3 are compared for circular, square and triangular geometry, as well as for linear and Rideal kinetics. Solutions for the two-dimensional model demonstrate that, as the reaction rate decreases from infinity to zero, the Sherwood number varies from the values of the Nusselt number characteristic of the Graetz-Nusselt problem with constant wall temperature to those with constant wall heat flux but with peripherally varying temperature. A lumped-parameter treatment, based on similarity with the constant wall temperature heat transfer problem, agrees satisfactorily with the solutions for a far more expensive two-dimensional model. The agreement is excellent for square channels, but the NH3 slip tends to be underestimated in the triangular geometry. The one-dimensional model reproduces successfully experimental effects of the NH3/NO feed ratio, and of the area velocity and the size of monolith channels.

An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A

Abstract: On August 17, 2017 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on the short gamma-ray burst GRB 170817A. Approximately 1.7 s prior to this GRB, the Laser Interferometer Gravitational-Wave Observatory (LIGO) triggered on a binary compact merger candidate associated with the GRB. This is the first unambiguous coincident observation of gravitational waves and electromagnetic radiation from a single astrophysical source and marks the start of gravitational-wave multi-messenger astronomy. We report the GBM observations and analysis of this ordinary short GRB, which extraordinarily confirms that at least some short GRBs are produced by binary compact mergers.

Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory.

Abstract: Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_CM = 110-170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory The average hadronic shower is 133 +- 016 (161 +- 021) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons

World squid fisheries

Abstract: Some 290 species of squids comprise the order Teuthida that belongs to the molluscan Class Cephalopoda Of these, about 30-40 squid species have substantial commercial importance around the world Squid fisheries make a rather small contribution to world landings from capture fisheries relative to that of fish, but the proportion has increased steadily over the last decade, with some signs of recent leveling off The present overview describes all substantial squid fisheries around the globe The main ecological and biological features of exploited stocks, and key aspects of fisheries management are presented for each commercial species of squid worldwide The history and fishing methods used in squid fisheries are also described Special attention has been paid to interactions between squid fisheries and marine ecosystems including the effects of fishing gear, the role of squid in ecosystem change induced by overfishing on groundfish, and ecosystem-based fishery management