Use of recycled carbon fibre as an additive in the manufacture of porous bricks more durable against salt crystallization

Within the framework of the Sustainable Development Goals of the Agenda 2030, the circular economy is being promoted as a means of ensuring a sustainable use of resources and a reduction in the amount of waste produced. The aim is to reduce the demand for often scarce raw materials through the continuous reuse, recycling and regeneration of materials and products. This paper explores the use of carbon fibre from wind turbine blades as an additive in the production of new efficient bricks. Clay mixes with 0, 5 and 10 wt% additive were fired at three temperatures (800, 950 and 1100 ºC) and the fired bricks were analysed from mineralogical and physical points of view to determine their suitability for use in the construction industry. The results show that carbon fibre improves the durability of the bricks, which became 16 % more porous as the firing temperature increased. However, the compressive strength of the bricks with 10 wt% carbon fibre was about 50 % lower than that of the control bricks made without additive. It is interesting to note that the distribution of the carbon fibres within the brick varies considerably and that they are shorter and wider in the core of the samples. These results could offer an alternative line for new product development in the brick industry. The bricks tested here are an example of a circular economy in which waste from one industrial process (wind turbine blades) is reused as an input in another (brick manufacture). The environmental benefits achieved are twofold: reduced demand for clay and recycling of decommissioned turbine blades, which are currently amassed in wind turbine graveyards.Funding for open access charge Universidad de Granada/CBUA.Junta de Andalucía Research Group RNM179Research Project B-RNM-188-UGR20 of the Regional Ministry of University, Research and Innovation of the Junta de Andalucía and FEDER, a way of making Europ

Novel reactivation allows effective reuse of Nafion® super-acid nano-catalyst

An alternative clean regeneration method to calcination on special grade resins, i.e. Nafion, is introduced. The reactivation strategy makes use of advanced oxidation processes (Fenton and non-Fenton) to remove the organic deposits generated from sequential catalytic cycles. Hot water treatment was considered as a control case to evaluate the extraction capacity of water itself at the oxidative conditions. Advanced oxidation processes were effective in reactivating the Nafion SAC-13 resin, which also rendered a cleaner and more sustainable reactivation process. Beta zeolite was studied as model fouled system prior to the Nafion SAC-13. Even though zeolites are considered to be thermally stable, this approach can be used when a full preservation of the acid sites is required. As far as resin Nafion SAC-13 is concerned, organic species deposition was found to be responsible of a selective poisoning of the sulfonic groups in Nafion, with a consequent drop in catalytic activity of the octanoic acid esterification with methanol. The Nafion resin was reactivated either with H2O2 or with Fenton chemistry; the resin remained stable under these oxidative conditions, which is the benefit of the presented non­thermal methodologies as compared to calcination. The optimal method showed full recovery of the initial activity and 90% of the final conversion. This methodology seems attractive for a whole-range of organic catalytic reactions, including those related to biomass valorization, that require the use of highly acidic catalysts, such as acidic resins, in liquid phase reactions

Regular Path Clauses and Their Application in Solving Loops

A well-established approach to reasoning about loops during program analysis is to capture the effect of a loop by extracting recurrences from the loop; these express relationships between the values of variables, or program properties such as cost, on successive loop iterations. Recurrence solvers are capable of computing closed forms for some recurrences, thus deriving precise relationships capturing the complete loop execution. However, many recurrences extracted from loops cannot be solved, due to their having multiple recursive cases or multiple arguments. In the literature, several techniques for approximating the solution of unsolvable recurrences have been proposed. The approach presented in this paper is to define transformations based on regular path expressions and loop counters that (i) transform multi-path loops to single-path loops, giving rise to recurrences with a single recursive case, and (ii) transform multi-argument recurrences to single-argument recurrences, thus enabling the use of recurrence solvers on the transformed recurrences. Using this approach, precise solutions can sometimes be obtained that are not obtained by approximation methods

HBPEI-grafted carbon nanotubes for the effective retention of Pd2+ and Pt2+ through complexation

Hyperbranched poly(ethyleneimine) (HBPEI) molecules in solution present high capacity to form stable complexes with transition metal ions due to the large number of amino groups ready to form chelates. We grafted HBPEI molecules to a multi-walled carbon nanotube (MWCNT) surface through covalent bonding, preparing solid hybrids which retain the chemical properties of the free poly-alkylamine molecules. In this way, we are able to transfer the complexation capacity of such molecules to a solid material adequate to act as a high-capacity sorbent for metal transition ions. We tested the HBPEI/MWCNT hybrids for the retention of Pd2+ and Pt2+ and the retention values obtained are much larger than those previously reported with fast retention kinetics. The kinetics and the XPS analysis of the metal ion/HBPEI/ MWCNT ensemble indicate that the retention takes place through the formation of chelates with two or three nitrogen atoms and with Cl− anions as co-ligands. Moreover, the results allow us to tune the metal loading on the hybrids by controlling the solution conditions. This is important because the XPS valence band analysis demonstrates that metal complexation directly modifies the electronic behaviour of the carbon nanotubes, which supports the stable covalent bond between HBPEI molecules and MWCNT and opens the possibility for tuning the electronic properties of the tubes.The financial support of the MINECO (projects MAT2014- 60104-C2-1-R and MAT2014-60104-C2-2-R), FEDER program, Autonomous Regional Government (J. de Andalucía, group RNM342) and Programa de Fortalecimiento de la I+D+i from UGR is acknowledged. The technical assistance of Centre of Instrumental Facilities, STI, of the University of Jaén is also acknowledged

Convergent validity of two items to differentiate between active and sedentary students

Este estudio examina la validez y fiabilidad de dos ítems de actividad física (AF) incluidos en el CHIP-CE para discriminar entre escolares activos y sedentarios. Se realizó un estudio observacional-transversal, con 1.073 escolares de ambos sexos, de 10-13 años. Mediante los ítems 13 y 28 del CHIP-CE se clasificó a los escolares como activos o sedentarios. La validez convergente fue examinada utilizando como criterio variables de adiposidad, lipídicas, metabólicas, de presión arterial y de fitness. El coeficiente de correlación de Spearman entre los dos ítems fue de 0,60. Los coeficientes de correlación de Spearman entre la media de los dos items de AF y las variables de salud mostraron valores más altos con el % grasa corporal, la insulina basal, la frecuencia cardiaca de recuperación y el fitness. La escala de dos ítems extraída del CHIP-CE es un instrumento válido para clasificar a los escolares en activos o sedentarios.This study examined the validity and reliability of two physical activity Child Health and Illness Profile - Child Edition (CHIP-CE) items to differentiate between active and sedentary students. An observational cross-sectional study design was used with 1,073 students from 11 to 13 years old, from 20 schools in the province of Cuenca (Spain). Item 13 and item 28 of the CHIP-CE, a generic childhood quality of life instrument, were evaluated. Convergent validity was examined using adiposity, lipidic, metabolic, blood pressure and cardiorespiratory fitness variables as criteria. The Spearman coefficient of correlation between the two items was 0.60. The Spearman correlation coefficients between the physical activity items and the anthropometric, lipidic, metabolic, blood pressure and cardiorespiratory fitness variables showed higher values with percentage body fat, fasting insulin, recovery heart rate and cardiorespiratory fitness. Our two-item questionnaire exhibited acceptable validity and high internal consistency for classifying students as either active or sedentary.Este estudio fue financiado por la Consejería de Sanidad de Castilla-La Mancha (beca GC03060-00). Financiación adicional fue obtenida del Ministerio de Sanidad y Consumo, Instituto de Salud Carlos III, Red de Investigación en Actividades Preventivas y de Promoción de Salud (grant RD06/0018/0038)

Caracterización química de la Fibra de Coco (Cocus nucifera L.) de México utilizando Espectroscopía de Infrarrojo (FTIR)

There is a growing interest in products with less environmental impact, this makes the use of natural fibers a viable alternative. The use of materials of biological origin is increasing in an attempt to reduce the amount of thermoplastic polymers from non-renewable sources. In this framework, the work characterizes the chemical characterization of coconut fiber (Cocus nucifera L.), by means of infrared spectroscopy (FTIR), and the spectra of the fibers of coconut, from two important growing sites, the Acapulco and San Jerónimo de Juárez regions, in the state of Guerrero, Mexico, the results obtained are compared with other spectra of other natural fibers, due to the high content of lignin, properties are attributed viscoelastic, by which it is inferred that when the fibers are subjected to a compression load or an impact force, the amorphous region (lignin) functions as a buffer and is resilient to the applied phenomena, a desirable characteristic in packaging materials, this proves that the coconut fiber with natural binder, could be a proposal to be used as packing material in packaging, the data corroborate a high percentage of cellulose and lignin present in the samples studied.Existe un creciente interés en productos con menor impacto ambiental, esto hace que el uso de fibras naturales sea una alternativa viable. El uso de materiales de origen biológico está aumentando en un intento de reducir la cantidad de polímeros termoplásticos de fuentes no renovables. En este marco se presenta el trabajo caracterización química de la fibra de coco (Cocus nucifera L.), mediante espectroscopía de infrarrojo (FTIR) , y se muestran los espectros de las fibras de coco, de dos lugares de cultivo importantes, la región de Acapulco y San Jerónimo de Juárez, en el estado de Guerrero, México , los resultados obtenidos son comparados con otros espectros de otras fibras naturales, debido al alto contenido de lignina se le atribuyen propiedades viscoelásticas, por lo que se infiere que al ser sometidas las fibras a una carga de compresión o una fuerza de impacto, la región amorfa (lignina) funciona como amortiguador y es resiliente a los fenómenos aplicados, una característica deseable en los materiales de embalaje, esto prueba que la fibra de coco con aglomerante natural, pudiera ser una propuesta para usarse como material de relleno en embalajes, los datos corroboran un alto porcentaje de celulosa y lignina presenteen las muestras estudiadas

Simultaneous PCR detection of ica cluster and methicillin and mupirocin resistance genes in catheter-isolated Staphylococcus

Recent data show that more than 50% of catheter-associated bloodstream infections are caused by staphylococci. Staphylococcal infections produced by intercellular-adhesion cluster (ica) carriers can be even more problematic due to the presence of methicillin and mupirocin resistance genes. In the present study, a multiplex PCR protocol that allows the simultaneous identification of staphylococci and detection of both the ica and methicillin and/or mupirocin resistance genes was developed. Furthermore, the method allows differential detection of the ica locus from Staphylococcus aureus and Staphylococcus epidermidis. [Int Microbiol 2004; 7(1):63–66