Pyrolysis and char reactivity of a poor-quality refuse-derived fuel (RDF) from municipal solid waste

The present study focuses on analyzing the pyrolysis and combustion behaviors of a refuse-derived fuel (RDF), which is generated in a MSW treatment plant located in Zaragoza (Spain). Pyrolysis experiments were carried out in a TGA apparatus and a fixed-bed reactor at different peak temperatures (400 and 600 °C) and heating rates (5 and 40 °C min- 1). The reactivity towards oxygen of produced chars was also measured in the same TGA device at a heating rate of 10 °C min- 1 and a final temperature of 800 °C. Pyrolysis results were significantly affected by peak temperature and heating rate. The found effect of peak temperature on char and fixed-carbon yields as well as on measured properties (H:C and O:C ratios, BET surface area and average pore diameter) was in agreement with previous studies. However, the effect of heating rate, especially on the release rate of volatiles, could be explained by a change in the pyrolysis reaction scheme. The RDF-derived chars obtained at the highest heating rate showed a higher reactivity in air. In addition, an increase in peak temperature also led to a higher reactivity. This result can indicate that the carbon present in the RDF-derived char is dispersed within an ash matrix containing a high number of active sites, the distribution of which could be improved when heating rate (and, to a lesser extent, peak temperature) is increased. The addition of 10 wt.% RDF to two-phase olive mill waste prior to slow pyrolysis led to an apparent increase in the carbonization efficiency as well as to an enhancement of the resultant char''s reactivity in air

Application of principal component analysis to identify pollen subtypes in Miconia (Melastomataceae)

Miconia Ruiz et Pav. es un género característico de regiones selváticas que en Argentina está representado por 10 especies. El objetivo de este trabajo fue la identificación de posibles subtipos polínicos en las especies argentinas de este género señalado como estenopalínico por estudios previos. Se midieron 60 granos de polen de cada una de las especies al microscopio óptico y se realizó un análisis de componentes principales y un árbol de recorrido mínimo, basados en una matríz de especies y variables morfométricas de los granos. Fueron seleccionados dos componentes principales que en conjunto explicaron el 77% de la variación total de los datos. La mayoría de las variables se correlacionaron con el componente 1. Seis especies se definieron en tres subtipos, restando cuatro que no pudieron ser incluidas en ninguno de ellos por presentar caracteres intermedios. Se concluyó que el análisis multivariado constituye una posible herramienta para ayudar a diferenciar subtipos polínicos dentro de géneros estenopalínicos.Miconia Ruiz et Pav. inhabits forest regions being represented in Argentina by 10 species. The aim of this study was to identify possible pollen subtypes in the Argentine species of Miconia. Previous studies found that the genus is stenopalynous. Pollen grains of each species were measured with an optical microscope and a PCA was conducted based on a matrix of species versus morphometric variables of pollen grains. Two components were selected because these explained together 77% of the total variation in the data. Most of the variables were correlated with component 1. Three pollen subtypes were defined in the genus, but four of the species could not be included in any of them because they presented intermediated characters. It was concluded that multivariate analysis is a possible tool that helps to differentiate pollen subtypes within stenopalynous genera.Fil: Ceballos, Sergio Javier. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: García, Maria E.. Fundación Miguel Lillo; ArgentinaFil: Slanis, Alberto C.. Fundación Miguel Lillo; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Reyes, Nora J. F.. Fundación Miguel Lillo; Argentin

Microtensile bond strength of several adhesive systems to different dentin depths

Abstract no. 15published_or_final_versio

Market Interest Rate Dynamics in Times of Financial Turmoil

The significant reduction of the monetary policy rate (MPR) during 2009 has offset the rise in lending rates caused by increased uncertainty in the country and abroad. This paper comes to this conclusion after examining the evolution of interest rates of consumer and commercial loans in order to distinguish between the effects caused by MPR transmission from those caused by the increases in risk premiums occurred in 2008. The above is done through counterfactual simulations using the relevant variables.

Polycomb RING1A- and RING1B-dependent histone H2A monoubiquitylation at pericentromeric regions promotes S-phase progression

The functions of polycomb products extend beyond their well-known activity as transcriptional regulators to include genome duplication processes. Polycomb activities during DNA replication and DNA damage repair are unclear, particularly without induced replicative stress.We have used a cellularmodel of conditionally inactive polycomb E3 ligases (RING1A and RING1B), which monoubiquitylate lysine 119 of histone H2A (H2AK119Ub), to examine DNA replication in unperturbed cells. We identify slow elongation and fork stalling during DNA replication that is associated with the accumulation of mid and late S-phase cells. Signs of replicative stress and colocalisation of double-strand breaks with chromocenters, the sites of coalesced pericentromeric heterocromatic (PCH) domains, were enriched in cells at mid S-phase, the stage at which PCH is replicated. Altered replication was rescued by targeted monoubiquitylation of PCH through methyl- CpG binding domain protein 1. The acute senescence associated with the depletion of RING1 proteins, which is mediated by p21 (also known as CDKN1A) upregulation, could be uncoupled from a response to DNA damage. These findings link cell proliferation and the polycomb proteins RING1A and RING1B to S-phase progression through a specific function in PCH replication.Ministerio de Economı́a y Competitividad BFU2010-18146, SAF2013-47997, BFU2013-42918-

Associahedra via spines

An associahedron is a polytope whose vertices correspond to triangulations of a convex polygon and whose edges correspond to flips between them. Using labeled polygons, C. Hohlweg and C. Lange constructed various realizations of the associahedron with relevant properties related to the symmetric group and the classical permutahedron. We introduce the spine of a triangulation as its dual tree together with a labeling and an orientation. This notion extends the classical understanding of the associahedron via binary trees, introduces a new perspective on C. Hohlweg and C. Lange's construction closer to J.-L. Loday's original approach, and sheds light upon the combinatorial and geometric properties of the resulting realizations of the associahedron. It also leads to noteworthy proofs which shorten and simplify previous approaches.Comment: 27 pages, 11 figures. Version 5: minor correction