823 research outputs found
Thermogravimetric and kinetic analysis of the decomposition of solid recovered fuel from municipal solid waste
The thermal decomposition of a solid recovered fuel has been studied using thermogravimetry, in order to get information about the main steps in the decomposition of such material. The study comprises two different atmospheres: inert and oxidative. The kinetics of decomposition is determined at three different heating rates using the same kinetic constants and model for both atmospheres at all the heating rates simultaneously. A good correlation of the TG data is obtained using three nth-order parallel reactions.Authors acknowledge the financial support for this work provided by PROMETEOII/2014/007 of Generalitat Valenciana (Spain) and CTQ2013-41006-R (Spanish Ministry of Economy and Competitiveness)
Modeling the thermal decomposition of automotive shredder residue
The pyrolysis and combustion of automotive shredder residue (ASR) were studied by dynamic thermogravimetry and derivative thermogravimetry at heating rates of 5, 15 and 30 K min−1 at atmospheric pressure. For the simulation of pyrolysis and combustion processes, two different kinetic models are proposed. One of them is based on the distribution of activation energies (DAEM), with three pools of reactants (three pseudocomponents) because of the complexity of the samples studied. The other model assumes a simple first-order decomposition of the three different fractions. The experimental thermogravimetric data of pyrolysis (oxygen absence) and combustion (at two different oxygen concentrations) processes were simultaneously fitted to determine a single set of kinetic parameters able to describe both processes at the different heating rates. The comparison of the models permits to discuss the importance to consider a DAEM. The experimental results and kinetic parameters may provide useful data for the design of thermal decomposition processing system using ASR as feedstock.Support for this work was provided by the CTQ2013-41006-R project from the Ministry of Economy and Competitiveness (Spain) and the PROMETEOII/2014/007 project from the Valencian Community Government (Spain)
Who discovered the binary system and arithmetic? Did Leibniz plagiarize Caramuel?
Gottfried Wilhelm Leibniz (1646–1716) is the self-proclaimed inventor of the binary system and is considered as such by most historians of mathematics and/or mathematicians. Really though, we owe the groundwork of today’s computing not to Leibniz but to the Englishman Thomas Harriot and the Spaniard Juan Caramuel de Lobkowitz (1606–1682), whom Leibniz plagiarized. This plagiarism has been identified on the basis of several facts: Caramuel’s work on the binary system is earlier than Leibniz’s, Leibniz was acquainted—both directly and indirectly—with Caramuel’s work and Leibniz had a natural tendency to plagiarize scientific works.2017-1
Regulation of sonic hedgehog-GLI1 downstream target genes PTCH1, Cyclin D2, Plakoglobin, PAX6 and NKX2.2 and their epigenetic status in medulloblastoma and astrocytoma
Abstract Background The Sonic hedgehog (Shh) signaling pathway is critical for cell growth and differentiation. Impairment of this pathway can result in both birth defects and cancer. Despite its importance in cancer development, the Shh pathway has not been thoroughly investigated in tumorigenesis of brain tumors. In this study, we sought to understand the regulatory roles of GLI1, the immediate downstream activator of the Shh signaling pathway on its downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6 in medulloblastoma and astrocytic tumors. Methods We silenced GLI1 expression in medulloblastoma and astrocytic cell lines by transfection of siRNA against GLI1. Subsequently, we performed RT-PCR and quantitative real time RT-PCR (qRT-PCR) to assay the expression of downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6. We also attempted to correlate the pattern of expression of GLI1 and its regulated genes in 14 cell lines and 41 primary medulloblastoma and astrocytoma tumor samples. We also assessed the methylation status of the Cyclin D2 and PTCH1 promoters in these 14 cell lines and 58 primary tumor samples. Results Silencing expression of GLI1 resulted up-regulation of all target genes in the medulloblastoma cell line, while only PTCH1 was up-regulated in astrocytoma. We also observed methylation of the cyclin D2 promoter in a significant number of astrocytoma cell lines (63%) and primary astrocytoma tumor samples (32%), but not at all in any medulloblastoma samples. PTCH1 promoter methylation was less frequently observed than Cyclin D2 promoter methylation in astrocytomas, and not at all in medulloblastomas. Conclusions Our results demonstrate different regulatory mechanisms of Shh-GLI1 signaling. These differences vary according to the downstream target gene affected, the origin of the tissue, as well as epigenetic regulation of some of these genes.http://deepblue.lib.umich.edu/bitstream/2027.42/78313/1/1471-2407-10-614.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78313/2/1471-2407-10-614.pdfPeer Reviewe
Sistemas caóticos y su aplicación a la encriptación de señales
La sincronización y control de señales caóticas es una activa área de investigación por sus posibles aplicaciones en telecomunicaciones y transmisión de señales [1, 2, 3, 4]. En el presente trabajo se estudia un sistema de comunicación basado
en la sincronización de dos sistemas no lineales caóticos, cada uno modelado a partir de las ecuaciones de movimiento de un péndulo forzado amortiguado y que se encuentran en el mismo punto de operación del espacio de parámetros.
Synchronization and control of chaotic signals is an active research area because of its applications
in telecommunications and secure signal transmission [1,2,3,4]. In this work a communication system
based in the synchronization of two chaotic nonlinear systems, each one being modeled by the motion
equations of a driven damped pendulum and operated in the same parameter space region is shown. Two
communication channels were used: the first one for the synchronizing signal and the second one for the
sent message. By using two channels the initial conditions sensibility problem is solved. In the receiver
system a feedback loop as a proportional controller is used in order to drive quickly the error between the
decoder and encoder states to zero. The last two facts make the system to be robust to external pertubative
signals such as noise in the communication channels
What does it mean for half of an empty cavity to be full?
21 págs.; 8 figs.; 2 app.; PACS numbers: 03.67.Bg, 03.70.+k, 11.10.-z© 2015 American Physical Society. It is well known that the vacuum state of a quantum field is spatially entangled. This is true in both free and confined spaces, for example, in an optical cavity. The obvious consequence of this, however, is surprising and intuitively challenging: namely, that in a mathematical sense, half of an empty cavity is not empty. Formally this is clear, but what does this physically mean in terms of, say, measurements that can actually be made? In this paper we utilize a local quantization procedure along with the tools of Gaussian quantum mechanics to characterize the particle content in the reduced state of a subregion within a cavity and expose the spatial profile of its entanglement with the opposite region. We then go on to discuss a thought experiment in which a mirror is very quickly introduced between the regions. In so doing we expose a simple and physically concrete answer to the above question: the real excitations created by slamming down the mirror are mathematically equivalent to those previously attributed to the reduced states of the subregions. Performing such an experiment in the laboratory may be an excellent method of verifying vacuum entanglement, and we conclude by discussing different possibilities of achieving this aim.This work is supported by Spanish MICINN
Projects FIS2011-29287 and CAM research consortium
QUITEMAD+ S2013/ICE-2801. E. B. acknowledges support
by the Michael Smith Foreign Study Supplements
Program, M. del R. was supported by a CSIC JAEPREDOC
grant and H. Westman was supported by the
JAE-DOC 2011 CSIC & ESF program. A. D. was supported
by the National Science Center, Sonata BIS Grant
No. 2012/07/E/ST2/01402.Peer Reviewe
Emissions from pyrolysis and combustion of automotive shredder residue
The present work has been carried out to verify the feasibility of thermal valorization of an automobile shredder residue (ASR). With this aim, the thermal decomposition of this waste has been studied in a laboratory scale reactor in order to analyze the pollutants emitted under different operating conditions. The emission factors of carbon oxides, light hydrocarbons, PAHs, PCPhs, PCBzs, PBPhs, PCDD/Fs, dioxin-like PCBs and PBDD/Fs were determined at two temperatures, 600 and 850ºC, and under varying oxygen ratios ranging from 0 (pure pyrolysis) to 1.5 (over-stoichiometric oxidation). After analyzing all these compounds we conclude that thermal valorization of ASR may be an efficient way to achieve the targets established in the Directive 2000/53/EC.Support for this work was provided by the CTQ2013-41006-R project from the Ministry of Economy and Competitiveness (Spain) and the PROMETEOII/2014/007 project from the Valencian Community Government (Spain)
Pollutant formation in the pyrolysis and combustion of Automotive Shredder Residue
The present work has been carried out to verify the feasibility of thermal valorization of an automobile shredder residue (ASR). With this aim, the thermal decomposition of this waste has been studied in a laboratory scale reactor, analyzing the pollutants emitted under different operating conditions. The emission factors of carbon oxides, light hydrocarbons, PAHs, PCPhs, PCBzs, PBPhs, PCDD/Fs, dioxin-like PCBs and PBDD/Fs were determined at two temperatures, 600 and 850 °C, and under different oxygen ratios ranging from 0 (pure pyrolysis) to 1.5 (over-stoichiometric oxidation). After analyzing all these compounds, we conclude that thermal valorization of ASR is a clean way to treat this waste.Support for this work was provided by the CTQ2013-41006-R project from the Ministry of Economy and Competitiveness (Spain) and the PROMETEOII/2014/007 project from the Valencian Community Government (Spain)
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