The incorporation of construction and demolition wastes as recycled mixed aggregates in non-structural concrete precast pieces

Concern for the environment has lately heightened awareness about the need for recycling in the construction industry. However, some standards, such as the Spanish standard, only accept the recycling of aggregates derived from concrete, which limits the extensive use of construction and demolition waste, which are produced in much bigger volumes. The aim of this work was to explore the possibility of using recycled mixed aggregates (RMA) in the preparation of precast non-structural concretes. To that end different percentages of natural aggregate were replaced by RMA in non-structural elements (25, 50, 75 and 100%). Contents of cement, water, and the dosages commonly used by companies were unchanged by the introduction of RMA. The characterization of the prepared elements has been done using the specific tests for each type of non-structural element (terrazzo for indoor use, hollow tiles, kerbstones and paving blocks): compression and flexural strength, water absorption, dimensional tolerances, abrasion and slipping resistance. The paving blocks, kerbstones, and hollow tiles prepared were tested for 360 days. The stability of the tested properties confirmed the possibility of using these wastes on an industrial scale satisfying the standard requirements. However, the surface of terrazzo with RMA is not as good as that prepared with natural aggregate.

Triassic redbeds in the Malaguide Complex (Betic Cordillera — Spain): petrography, geochemistry and geodynamic implications

Sandstone petrography and mudstone mineralogy and geochemistry of Triassic mudstones and sandstones from continental redbeds of the Malaguide Complex (Betic Cordillera, southern Spain) provide useful information on provenance, palaeoclimate and geodynamics during the early stages of the Pangea break-up, and on their diagenetic evolution. The sandstones are quartzarenites to sub-litharenites, with minor lithic fragments and rare feldspars. The mudstone samples show a PAAS like elemental distribution. The samples likely record recycling processes from their metasedimentary basement rocks that significantly affected the weathering indices, and monitors cumulative effects, including a first cycle of weathering at the source rocks. Sandstone composition and chemical–mineralogical features of mudstones record a provenance derived from continental block and recycled orogen that were weathered under warm and episodically wet climate. Source areas were located towards the east of the present-day Malaguide outcrops, and were formed by fairly silicic rock types, made up mainly of Palaezoic metasedimentary rocks, similar to those of the Paleozoic underlying series, with subordinate contributions from magmatic–metamorphic sources, and a rare supply from mafic metavolcanic rocks. Clay-mineral distribution of mudstones is dominated by illite and illite/smectite mixed-layer that result from differences in provenance, weathering, and burial/temperature history. Illite crystallinity values, illitization of kaolinite, occurrence of typical authigenic minerals and apatite fission-track studies, coupled with a subsidence analysis of the whole Malaguide succession suggest burial depths of at least 4–6 km with temperatures of 140–160 °C, typical of the burial diagenetic stage, and confirm the Middle Miocene exhumation of the Betic Internal Domain tectonic stack topped by the Malaguide Complex.

Compositional and Geochemical Signatures for the Sedimentary Evolution of the Middle Triassic–Lower Jurassic Continental Redbeds from Western-Central Mediterranean Alpine Chains

Compositional and chemical analyses suggest that Middle Triassic–Lower Liassic continental redbeds (in the internal domains of the Betic, Maghrebian, and Apenninic chains) can be considered a regional lithosome marking the Triassic-Jurassic rift-valley stage of Tethyan rifting, which led to the Pangaea breakup and subsequent development of a mosaic of plates and microplates. Sandstones are quartzose to quartzolithic and represent a provenance of continental block and recycled orogen, made up mainly of Paleozoic metasedimentary rocks similar to those underlying the redbeds. Mudrocks display K enrichments; intense paleoweathering under a hot, episodically humid climate with a prolonged dry season; and sediment recycling. Redbeds experienced temperatures in the range of 100°–160°C and lithostatic/tectonic loading of more than 4 km. These redbeds represent an important stratigraphic signature to reconstruct a continental block (Mesomediterranean Microplate) that separated different realms of the western Tethys from Middle-Late Jurassic to Miocene, when it was completely involved in Alpine orogenesis.

Pràctica 11. Què podem fer davant d’un xiquet...

Les realitats de les escoles infantils són molt diverses, ja que no solament integren xiquets amb diferents capacitats per a aprendre, interessos i motivacions, sinó també xiquets amb diferents contextos socials i culturals de procedència. Aquest fet, conjuntament amb la diversitat de centres i professionals que els integren, fa que l’escola siga un laboratori per a l’aprenentatge professional i que el dia a dia proporcione moltes d’experiències enriquidores i plenes de coneixement. En aquesta pràctica apareixen alguns dubtes i necessitats reals manifestades per mestres i educadors d’escoles infantils. La seua senzillesa i claredat és un indicador que en educació infantil el que importa és el concret, el proper i els petits detalls de les coses sense deixar de ser per això menys rellevants.

Nuevos materiales absorbentes acústicos obtenidos a partir de restos de botellas de plástico

En el ámbito de acústica de la edificación es común el uso de materiales fibrosos como materiales absorbentes acústicos. Uno de estos materiales cada vez más utilizado es la lana de poliéster. Un problema que presenta el chip virgen de poliéster es que se obtiene del petróleo, cuyo precio no hace más que incrementarse en los últimos años. En este trabajo se presenta una lana de poliéster alternativa, obtenida mediante el tratamiento del PET, a través del conveniente ciclo de reciclado de botellas de plástico. Se comparan valores del coeficiente de absorción; en incidencia normal y en cámara reverberante de los materiales elaborados a partir de chip virgen y de las nuevas lanas obtenidas del PET. Además, se propone un modelo empírico de comportamiento acústico de estas nuevas lanas. Los resultados obtenidos han sido favorables, la fibra virgen ya ha sido sustituida por fibra reciclada en su proceso de fabricación.

Evaluation of Two Alternative Procedures for Measuring Airflow Resistance of Sound Absorbing Materials

It is well known that sound absorption and sound transmission properties of open porous materials are highly dependent on their airflow resistance values. Low values of airflow resistance indicate little resistance for air streaming through the porous material and high values are a sign that most of the pores inside the material are closed. The laboratory procedures for measuring airflow resistance have been stan- dardized by several organizations, including ISO and ASTM for both alternate flow and continuous flow. However, practical implementation of these standardized methods could be both complex and expensive. In this work, two indirect alternative measurement procedures were compared against the alternate flow standardized technique. The techniques were tested using three families of eco-friendly sound absorbent materials: recycled polyurethane foams, coconut natural fibres, and recycled polyester fibres. It is found that the values of airflow resistance measured using both alternative methods are very similar. There is also a good correlation between the values obtained through alternative and standardized methods.

Tirant lo Blanch plurilingüe. De la traducció com a eina per estudiar millor els originals i escampar-ne el coneixement

La novel·la del cavaller valencià Joanot Martorell, Tirant lo Blanch (València, 1490; amb una segona edició a Barcelona, també incunable, 1497), és un magnífic representant de la cultura dels valencians i, en general, de la Corona d'Aragó. Aquesta novel·la és una obra mestra de la literatura medieval i del Renaixement i una aportació fonamental de la Corona d'Aragó, i, més en concret, de les Lletres Valencianes, al desenvolupament de la novel·la moderna i al cànon cultural occidentals. L'obra de Martorell ha gaudit sempre un reconegut prestigi, ja d'ençà que Miguel de Cervantes, al capítol sisé del Quixot, en digués "el mejor libro del mundo"; i és establert que el Tirant va influir en diversos dels aspectes que han contribuït a individuar el Quixot com una obra que no encaixava en el panorama dels "libros de caballería" castellans de l'època i que, tanmateix -i per això mateix- contribueixen a l'enorme valor afegit de l'obra de Cervantes. Tirant lo Blanch, a través de Tirante el Blanco, aporta un cabal fonamental per a fer possible el to i inclús l'estil polifònic i el tractament en cert punt irònic de la mimesi literària tan característic en l'obra de Cervantes gràcies al contrast entre la bogeria llibresca d'Alonso Quijano i el sentit comú de Sancho (NAVARRO 2011). Tirant-Tirante no perd mai de vista la realitat, fins i tot mor al llit, d'un mal real i humà, una angina de pit, després de dictar personalment el seu testament i després de deixar els seus assumptes arreglats. El Quixot també morirà, en un context i ambient de realitat, i no com solia produir-se la mort en els llibres de cavalleries. En definitiva, de la mateixa manera que la seua versió original, aquesta versió en espanyol constitueix una obra excepcional en el context de la literatura de tema cavalleresc en l'Edat Mitjana i poc o no res té a envejar a les obres de Chrétien de Troyes o amb la Quête du Saint Graal o la Vulgata en conjunt (MARTINES, 1995; HAUF, 1995).

El año de la primera campaña de vacunación oral contra la poliomielitis según la prensa de Santander (1963)

La poliomielitis emergió como una devastadora epidemia en los países desarrollados durante la primera mitad del siglo XX. Los hallazgos de una vacuna inactivada por Salk (1955) y otra atenuada por Sabin (1957) ofrecieron una solución para eliminarla, coincidiendo con el periodo de mayor incidencia de la enfermedad en España (1950-1963). La respuesta de las autoridades sanitarias españolas no se concretó hasta el año de 1963, cuando el Ministerio de Fomento organizó una campaña nacional de inmunización con vacuna inactivada. Estudios epidemiológicos realizados por investigadores de la Escuela Nacional de Sanidad llevaron al convencimiento de utilizar la vacuna atenuada y a un cambio de estrategia que originó en otoño del mismo año una nueva campaña nacional a cargo del Ministerio de la Gobernación. Este estudio de caso analiza la difusión mediática de ambas campañas en Santander, mediante una revisión de las noticias de prensa publicadas en 2 diarios de ámbito provincial.

Cobalt-Impregnated Magnetite as General Heterogeneous Catalyst for the Hydroacylation Reaction of Azodicarboxylates

Catalysts consisting of cobalt and nickel impregnated on magnetite have been prepared, characterized and used for the hydroacylation reaction of different azodicarboxylate compounds with aldehydes, using nearly stoichiometric amounts of both reagents in only 3 h. Furthermore, this reaction has been conducted with the smallest amount of catalyst. The cobalt catalyst is stable enough to be removed by magnetic decantation and recycled ten-fold without any detrimental effect on the results.

Acoustic properties of porous concrete made from arlite and vermiculite lightweight aggregates

The use of sustainable materials is becoming a common practice for noise abatement in building and civil engineering industries. In this context, many applications have been found for porous concrete made from lightweight aggregates. This work investigates the acoustic properties of porous concrete made from arlite and vermiculite lightweight aggregates. These natural resources can still be regarded as sustainable since they can be recycled and do not generate environmentally hazardous waste. The experimental basis used consists of different type specimens whose acoustic performance is assessed in an impedance tube. Additionally, a simple theoretical model for granular porous media, based on parameters measurable with basic experimental procedures, is adopted to predict the acoustic properties of the prepared mixes. The theoretical predictions compare well with the absorption measurements. Preliminary results show the good absorption capability of these materials, making them a promising alternative to traditional porous concrete solutions.

Palladium(II) oxide impregnated on magnetite as a catalyst for the synthesis of 4-arylcoumarins via a Heck-arylation/cyclization process

Heck-arylation/cyclization was achieved using heterogeneous palladium(II) oxide impregnated on magnetite catalyst (2.5 mol%) with a lower catalyst loading than that reported for similar processes. Ethanol was used as a non-toxic and bio-renewable solvent. Good yields were afforded using a broad range of substrates (40–98%). The catalyst could be partially recycled, and analyses confirmed the almost total reduction of palladium(II) oxide to palladium(0) as well as the iodine poissoning effect, which is the main barrier to complete recyclability.

Silica Microparticles Supported Gold and Copper Ferrite Nanoparticles: A Magnetically Recyclable Bimetallic Catalyst for Sonogashira Reaction

Novel silica supported gold and copper ferrite nanoparticles (NPs) have been synthesized, characterized and used as a separable dual catalyst in Sonogashira type reaction. These Au.CuFe2O4@Silica NPs show a high efficiency as catalyst in the alkynylation not only of aryl iodides but also aryl bromides. By using only 0.5 mol% loading and t-BuOK as base in N,N-dimethylacetamide as solvent, aryl iodides react at 115 ºC in 1 d, whereas for aryl bromides the cross-coupling takes place at 130 ºC in 2 d. The catalyst can be successfully recycled using an external magnet for four consecutive runs.

La Legenda aurea com a font del teatre hagiogràfic català de tècnica medieval: un tast comparatiu

En aquest treball ens proposem estudiar la influència de la Legenda aurea de Jacobus de Voragine en el teatre hagiogràfic català de tècnica medieval, en concret en tres de les consuetes del ms. 1139 de la BNC: la de sant Jordi, dedicada a l’episodi de la donzella i el drac; la de la conversió de sant Cristòfol i la de sant Mateu. Comptem amb algunes aproximacions anteriors, com és el cas de les consideracions que féu Josep Romeu en la seua edició de les peces hagiogràfiques d’aquest manuscrit (1957). En aquest sentit, aprofitem les seues indicacions com a punt de partida per a oferir una anàlisi més detallada de la manera en què els drames hagiogràfics adapten algunes de les vides contingudes en l’obra de Voragine. Per no allargar-nos excessivament, ens centrem en aquestes tres consuetes, ja que poden ser prou representatives dels diferents tipus d’adaptació teatral de la Legenda aurea.