Recent Advances in Homogeneous Metal-Catalyzed Aerobic C–H Oxidation of Benzylic Compounds

Csp(3)-H oxidation of benzylic methylene compounds is an established strategy for the synthesis of aromatic ketones, esters, and amides. The need for more sustainable oxidizers has encouraged researchers to explore the use of molecular oxygen. In particular, homogeneous metal-catalyzed aerobic oxidation of benzylic methylenes has attracted much attention. This account summarizes the development of this oxidative strategy in the last two decades, examining key factors such as reaction yields, substrate: catalyst ratio, substrate scope, selectivity over other oxidation byproducts, and reaction conditions including solvents and temperature. Finally, several mechanistic proposals to explain the observed results will be discussed.(IT-774-13 (Basque Government) and CTQ2017-86630-P (Spanish Ministry of Economy and Competitiveness) projects

Egitura-zehaztapenerako ariketa ebatziak

104 p.Egitura-determinazioan jarduten duten ikasleen zein profesionalen trebakuntzan laguntzea da ariketa ebatziz osoturiko liburu honen helburu nagusia. Azken finean, lehen ariketa errazetatik hasita azken adibide konplexuenera, ikaslea gidatzea da liburu honen zeregina. UV-Vis, IR, MS, eta NMR espektro sinpleak lantzen dira lehenik, ondoren gaur egungo esperimentu aurreratuagoetara helduz, seinale/banda/tontorren esanahaia eta beren ondorioa igarri nahi den konposatu ezezagunaren egituran adibide praktikoen bitartez azaltzen direlarik. Halaber, eskuratutako informazioa nola bildu, ustezko egitura kimikoa (ezaugarri estereokimikoak ere barne) proposatzeko eta esleipenerako irispideak ematen dira

Seats and their anchorages strength in coaches under rollover.

The introduction of safety belts in the passengers’ seats of coaches could have important repercussions increasing their safety under frontal impact and rollover. This type of vehicles has a particularity from cars or trucks: the safety belts are fixed directly to the seats and not to the vehicle structures. A lot of work has been made in Europe (and it is being made) to define requirements for seats, seats’ anchorages, restraint systems and safety belts’ anchorages to guarantee the correct retention of the passengers in their seats under frontal impacts. In case of rollover, the belted passengers increase the energy that must be absorbed by the superstructure because some of their mass must be considered us rigidly joined to the vehicle. This situation has been taking into account in the current European legislation (Regulation UN-ECE 66, Revision 01). This version of the Regulation has increased the requirements for the superstructure to assure that the behaviour of the superstructure is as good as in the vehicles without belted passengers preserving the survival space. This new revision is going to be mandatory for new types from October 2010 (and for new matriculations from October 2017), but a considerable number of coaches’ manufactures are modifying their structures under this new revision because they take in mind that if the safety belts are yet included in the coaches, the superstructure must be in accordance. This is an important effort of redesign: more resistant structures but without weight increase

CO2 emissions from a spark ignition engine operatin on natural-hydrogen blends (HCNG)

The addition of hydrogen to natural gas could be a short-term alternative to today’s fossil fuels, as greenhouse gas emissions may be reduced. The aim of this study is to evaluate the emissions and performance of a spark ignition engine fuelled by pure natural gas, pure hydrogen, and different blends of hydrogen and natural gas (HCNG). Increasing the hydrogen fraction leads to variations in cylinder pressure and CO2 emissions. In this study, a combustion model based on thermodynamic equations is used, considering separate zones for burned and unburned gases. The results show that the maximum cylinder pressure rises as the fraction of hydrogen in the blend increases. The presence of hydrogen in the blend leads to a decrease in CO2 emissions. Due to the properties of hydrogen, leaner fuel–air mixtures can be used along with the appropriate spark timing, leading to an improvement in engine emissions with no loss of performance

1.3 MÉTODOS Y TÉCNICAS DE LA INVESTIGACIÓN

SÓLO VISIÓN PROYECTABLE

UNIDAD III: TECNICAS DE RECOPILACION Y REGISTRO DE DATOS

SOLO VISION PROYECTABLE

Nuevos Requisitos y Avances en Seguridad Pasiva en Autobuses y Autocares: Situación Actual y Necesidades

La seguridad pasiva en los autobuses y autocares viene marcada fundamentalmente por la aparición de reglamentación que impone requisitos a las estructuras y sistemas de retención de estos vehículos para garantizar la seguridad de sus ocupantes. En los últimos años se han realizado numerosos avances en seguridad que han conllevado (y siguen arrastrando) la necesidad de estudios de investigación para determinar qué requisitos hay que imponer sobre los mismos (niveles de esfuerzos, deformación, energía…). En la reglamentación Europea destacan: - Seguridad ante impactos frontales, con la incorporación de cinturones de seguridad, que ha conllevado un gran esfuerzo y modificaciones tanto a los fabricantes de asientos, carroceros como a las oficinas técnicas. - Seguridad ante vuelco, con el aumento en los requisitos de resistencia estructural a vuelco, que está suponiendo hoy por hoy nuevas soluciones técnicas para las carrocerías. El trabajo presenta un resumen de la situación actual así como de los principales estudios prelegislativos realizados por el INSIA-UPM para determinar que requisitos deben cumplir estos vehículos, en función de la accidentalidad existente, fundamentalmente a vuelco y ante impacto frontal. Se destacan también las carencias existentes actualmente. Por ejemplo tenemos reglamentación que verifique la resistencia estructural a vuelco y la correcta retención de los pasajeros ante impacto frontal. Pero no hay nada que garantice la resistencia estructural ante impacto frontal ni la correcta retención en caso de vuelco. Este trabajo presenta algunas ideas en estos aspectos (cálculos y ensayos)