Valorization of keratin biofibers for removing heavy metals from aqueous solutions

Four common waste keratin biofibers (human hair, dog hair, chicken feathers, and degreased wool) have been used as biosorbents for the removal of heavy metal ions from aqueous solutions. Different parameters of the biosorption processes were optimized in batch systems. For multiple-metal systems, consisting of a mixture of eight metal ions [Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II)], the total metal biosorption increased in the order: degreased wool¿>¿chicken feathers¿>¿human hair¿>¿dog hair. From the kinetic models tested, the pseudo-second-order model provided better results. Furthermore, biosorption isotherms of Pb(II) with the different keratin biofibers fitted the Langmuir model. Surface morphology of the biosorbents were analyzed before and after the sorption using Fourier transform infrared spectroscopy and scanning electron microscopy. The keratin biofibers tested are potentially good sorbents of metal ions, with degreased wool and chicken feathers being the more efficient onesPostprint (author's final draft

Classical and quantum-linearized descriptions of degenerate optomechanical parametric oscillators

Recent advances in the development of modern quantum technologies have opened the possibility of studying the interplay between spontaneous parametric down-conversion and optomechanics, two of the most fundamental nonlinear optical processes. Apart from practical reasons, such scenario is very interesting from a fundamental point of view, because it allows exploring the optomechanical interaction in the presence of a strongly quantum-correlated field, the spontaneously down-converted mode. In this work we analyze such problem from two approximate but valuable perspectives: the classical limit and the limit of small quantum fluctuations. We show that, in the presence of optomechanical coupling, the well-known classical phase diagram of the optical problem gets modified by the appearance of new dynamical instabilities. As for the quantum-mechanical description, we prove the ability of the squeezed down-converted field to cool down the mechanical motion not only to thermal but also to squeezed thermal mechanical states, and in a way that can be much less sensitive to parameters (e.g., detuning of the driving laser) than standard sideband cooling.Comment: New version including the quantum linearized description of the system and appendices. Accepted in Physical Review

Properties and optimal manufacturing conditions of chicken feathers thermoplastics biocomposites

The aim of this study was the analysis and characterization of composites based on thermoplastics (ethylene vinyl acetate, polypropilene and high-density polyethylene) and chicken feathers. Several composite samples with a content of 20% v/v of chicken feathers have been studied to determine the optimal manufacturing conditions of temperature, mixing time, and mixing speed to achieve the best tensile properties. The results have shown that the addition of micronized chicken feather (20% v/v) to thermoplastic matrices increases stiffness and provides a more brittle behavior. Ethylene vinyl acetate matrix also shows an ability to participate in second-order intermolecular interactions with chicken feathers, providing better tensile properties (tensile strength and toughness) than polypropilene and high-density polyethylene. Optimal manufacturing conditions were found for a mixing time of around 5min; a mixing speed of 50rmin 1 ; and temperature values of 160 C in case of high-density polyethylene, 120 C for ethylene vinyl acetate, and 170 C for polypropilene. Fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy analysis have been performed in order to provide further understanding of the compatibility and microstructural features that support the tensile properties of the materialsPostprint (author’s final draft

Oxidative degradation of a novel AMP/AEP blend designed for CO2 capture based on partial oxy-combustion technology

Versión aceptada. Embargo 24 mesesSolvent degradation and volatile compound emissions are two of the major concerns about the deployment of carbon capture technologies based on chemical absorption. In this context, partial oxy-combustion might reduce the solvent degradation due to the use of a higher CO2 concentrated flue gas. This work evaluates the oxidative degradation of a novel AMP/AEP blend, namely POS #1, under partial oxy-combustion conditions. The effects of temperature and flue gas composition were evaluated in terms of solvent loss, degradation rates, NH3 emissions and degradation products. The experiments were set at temperatures up to 70 °C and two levels of O2 concentration – 3%v/v and 6%v/v. The CO2 concentration of the flue gas ranged between 15%v/v and 60%v/v CO2. The novel solvent POS#1 showed high resistance to degrade and resulted in lower degradation rates than MEA in all the operating conditions evaluated in this work. The maximum degradation of AEP and AMP was 24% and 19%, respectively. MEA degraded almost double under the same conditions. Temperature and O2 concentration enhanced the oxidative degradation of POS #1. However, the use of higher CO2 concentration in the flue gas led to lower degradation rates of AEP and AMP and hence oxidative degradation was partially inhibited under partial oxy-combustion conditions. The presence of higher CO2 content in the flue gas decreased the NH3 production and a 70% reduction of its emissions was achieved as the CO2 concentration shifted from 15%v/v to 60%v/v. Other major degradation compounds such as formate and 2,4-lutidine were also decreased. New degradation products were not identified so that the suggested degradation pathways proposed in the literature were not influenced by the presence of higher CO2 concentrations.Ministerio de Economia y Competitividad CTM-2014-58573-RUnión Europea, European Development Research Fund (EDRF

The international cooperation of businesses in order to improve local public services

Changes in local government policies about the management of public services has been the focus of many investigations all around the world. However, what has not been studies is how some of the new models have relied upon international business alliances in order to improve the public services provided. A qualitative analysis, based on case studies of alliances between Colombian and Spanish companies, have been performed to help address this question. The results indicate that the changes in local policies have not only improved the public services but, with the agreements signed, a strong and agile partnership has been achieve

Comparar los efectos de la resistencia del concreto en losas aligeradas e=0.20 m, curado con diferentes métodos, Chiclayo - 2018

El tema de tesis “Comparar los efectos de la resistencia del concreto en losas Aligeradas e=0.20 m, curado con diferentes métodos” es una investigación de tipo experimental – aplicativa – descriptiva. En la presente tesis de investigación tuvo como objetivo principal es determinar la resistencia a la compresión de las losas de concreto, por efecto de los diferentes métodos de curados. Se realizaron varios tipos de ensayos incluido el diseño de mezclas, pruebas de granulometría gruesa, pruebas de granulometría fina, cálculo de la humedad, peso específico y peso unitario grueso de los agregados que intervinieron. Por lo que, al utilizar tres tipos de curado con aditivo en losas aligeradas, curado con arroceras y con bolsas de cemento se concluyó que la variación entre la resistencia de los concretos depende directamente del método de curado, Los cuales no llegaron a la resistencia requerida f’c=210 kg/cm2. Los ensayos de realizaron en la escuela de ingeniería civil de la universidad “Cesar Vallejo”

Experiència per a la integració compartida de competències genèriques a les assignatures d’experimentació en enginyeria química

Peer Reviewe

CONPLUMAS: valorización de residuos biogénicos fibrosos para la obtención de nuevos materiales

Postprint (published version

Evolution et principes fondamentaux des essais de solidité: lumière et intempérie

El objetivo del presente trabajo es mostrar la evolución y los fundamentos que sustentan los ensayos normalizados modernos de solidez a la luz y a la intemperie de los textiles, para comprender el porqué de los mismos y la validez de los métodos actualesThe aim of this paper is to show the evolution and fundamentals of modern standardized methods to measure colour fastness of textiles to light and weathering, to understand the reasons of their development and the validity of the current testsLe but de cet article est de montrer l'évolution et les bases des essais normalisés modernes de solidité à la lumière et aux intempéries de textiles, afin de comprendre les raisons et la validité des méthodes actuellesPeer Reviewe