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The static bending properties, different strain rates and interlaminar shear strength (ILSS) of carbon-fiber-reinforced polymers (CFRP) with two epoxy resins nano-enhanced with carbon nanofibers (CNFs) are studied. The effect on ILSS behavior from aggressive environments, such as hydrochloric acid (HCl), sodium hydroxide (NaOH), water and temperature, are also analyzed. The laminates with Sicomin resin and 0.75 wt.% CNFs and with Ebalta resin with 0.5 wt.% CNFs show significant improvements in terms of bending stress and bending stiffness, up to 10%. The values of ILLS increase for higher values of strain rate, and in both resins, the nano-enhanced laminates with CNFs show better results to strain-rate sensitivity. A linear relationship between the logarithm of the strain rate was determined to predict the bending stress, bending stiffness, bending strain and ILSS for all laminates. The aggressive solutions significantly affect the ILSS, and their effects are strongly dependent on the concentration. Nevertheless, the alkaline solution promotes higher decreases in ILSS and the addition of CNFs is not beneficial. Regardless of the immersion in water or exposure to high temperatures a decrease in ILSS is observed, but, in this case, CNF content reduces the degradation of the laminates.

The polymeric optical fibre technology can be successfully used for UV spectrum range radiation measurements.Anew type of fluorescent optical fibre optode is presented. The used fluorescent wave-shifter was used for UV-VIS conversion and radiation measurements. The linear characteristic with sensitivity 480 mW−1 is presented for UV range 7.2-13.6 mW. Presented optode construction advantages (small dimensions, low weight, high immunity to electromagnetic fields and distributed sensor architecture possibility) are attractive for numerous composite based engineering applications.

The demand for mixed joints of hard-welded steels used in civil engineering and transport is increasing. An example of this can be welding of pins of high-strength steel S690 QL (1.8928) with the arms of a movable platform made of DOCOL 1200M steel from the AHSS group. This joint is difficult to make properly, due to significant differences in the thickness of welded elements and different chemical composition of both steels. The thickness of the cylindrical pin is 40 mm, the diameter of the pin is 50 mm. The thickness of the metal sheet used for the mobile platform arm is 2 mm. . Joints of varying thickness and chemical composition may have cracks in the heat affected zone and in the weld. The purpose of the article is to determine the most appropriate welding parameters and the selection of filler materials that will allow to obtain the correct joint without welding defects.

The compound of poly(lactic acid) (PLA) and cellulose was made by the emulsion-solvent evaporation technique in order to obtain spheres which are then compression molded to produce a biocomposite film. The effect of the dispersant (poly(vinyl alcohol)&mdash, PVA)/PLA ratio on the spheres yield was studied. Moreover, to evaluate the effect of cellulose particle size and surface chemistry on the process yield, unbleached eucalypt kraft pulp and microcrystalline cellulose (MCC), both unmodified and physically or chemically modified were used. PLA/cellulose spheres were characterized regarding its physical properties. It was found that the spheres yield is essentially determined by the PVA/PLA ratio and the percentage of cellulose incorporation is greatly affected by the surface chemistry of cellulose. Regarding the films, DSC runs showed a significant effect of the cellulose type incorporated into PLA matrix on the cold crystallization temperature and on the degree of crystallinity of the biocomposite films. The measurement of tensile properties of the biocomposite films revealed that the strength, elongation at break and toughness (tensile energy absorption at break) of the films incorporating unmodified and chemically modified MCC were substantially improved.

The aim of this work is to determine the values of the hardness and elastic modulus of the phases present in CaZrO3-MgO-ZrO2 composites and to analyse their contribution to the composite properties. Two materials previously developed with the same major phases (CaZrO3, MgO and c-ZrO2) present in different volume fractions and grain size have been analysed. The hardness and Young´s modulus of each phase determined by nanoindentation are independent from the specific composite and coincident with nanoindentation values for single phase bulk materials. The contribution of the individual phases to Young´s modulus of the multiphase materials is in agreement with calculations using the nanoindentation values and the Voight upper limit of the “rule of mixtures”. Scale dependence due to microcracking has been observed for microhardness values of the composites and differences between calculations and experimental values are related to this effect., This work was performed in the frame of the CYTEDnetwork HOREF(312RT0453)and was supported by the Spanish Government underprojectMAT2013-48426-C2-1-R.AbílioP.Silvaacknowledges thefinancialsupportofJECSTrustthroughmobilityContract201597 and Instituto de Cerámica y Vidrio–CSIC.

The wear behaviour of a fine grained and dense CaZrO3-MgO composite is presented. Un-lubricated Pin-on-disc tests at room temperature have been performed using 10 N as normal force and 0.10–0.15 ms-1 as sliding rate and ZrO2 and steel counterparts. The coefficient of friction versus the sliding distance and the specific wear, together with a complete microstructural analysis of the worn surfaces by field emission scanning electron microscopy is reported. The composite presents a wear resistance similar to other ceramics under ceramic/ceramic sliding contact and improved wear resistance in contact with steel. Initial wear is dominated by abrasion independently of the chemical nature of the counterpart. The second stage wear depends on the characteristics of the third body formed. Zirconia leads to a brittle particulate third body with little protective capability. Steel forms a strongly bonded and plastic cermet third body that protects the material limiting the level of further wear. Fil: Silva, Abílio. Instituto de Ceramica y Vidrio de Madrid; España. Universidade Beira Interior; Portugal Fil: Booth, Raul Fernando Nicolas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina. Instituto de Ceramica y Vidrio de Madrid; España Fil: Garrido, Liliana Beatriz. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Aglietti, Esteban Fausto. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Pena, Pilar. Instituto de Ceramica y Vidrio de Madrid; España Fil: Baudín, Carmen. Instituto de Ceramica y Vidrio de Madrid; España

Processing and properties of two fine grain and dense CaZrO3-MgO based composites obtained by reaction sintering of pure ZrO2 and dolomite (CaMg(CO3)2) are described. Two dolomites with different levels of impurities were used to fabricate the materials: high purity (impurity content ≈1.2 wt.%, material DBZ) and impure dolomite (impurity content ≈6.12 wt.%, material DNZ). Mixtures (molar 1:1) were attrition milled and the reaction and sintering processes were studied using dynamical techniques (DTA-TG and dilatometry). Adequate sintering schedule was selected using the controlled sintering technique. The role of impurities on the physical characteristics, microstructure and mechanical properties of the obtained composites was analysed. Noticeable changes in microstructure, porosity, grain size and phases, were observed as function of final sintering temperature at 1350, 1400, 1450 °C, and impurity content. The obtained microstructures are discussed on the basis of the phase equilibrium relationships. Fil: Booth, Raul Fernando Nicolas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina. Instituto de Ceramica y Vidrio de Madrid; España Fil: Garrido, Liliana Beatriz. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Aglietti, Esteban Fausto. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Tecnología de Recursos Minerales y Cerámica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Tecnología de Recursos Minerales y Cerámica; Argentina Fil: Silva, Abílio. Instituto de Ceramica y Vidrio de Madrid; España. University of Beira Interior; Portugal Fil: Pena, Pilar. Instituto de Ceramica y Vidrio de Madrid; España Fil: Baudín, Carmen. Instituto de Ceramica y Vidrio de Madrid; España

This work aims to contribute for the development of bioglass scaffolds to be used in bone tissue regeneration. Starting from the classic quaternarian composition of the bioglass 45s5 it was added potassium oxide and magnesium oxide in order to obtain the optimised system: SiO2-CaO-Na2O-MgO-K2O-P2O5, improving the mechanical resistance and the bioactivity behaviour. The mixture was reached by a fusion at 1500 ºC followed by thermal shock, the resulting bioglass was milled to get a particle size less than 40 µm and it was homogenised with a porogen agent (salt), resulting the pressed specimens at 100 MPa of 100, 60, 50, and 40 wt.% of bioglass. After sintering, bleaching and maturation, it was evaluated the mechanical behaviour, toxicity and bioactivity, proving the viability and potential of this simplified method of scaffold’s manufacture, also putting in evidence the advantages of the using salt as a porogen agent in the morphology and structure obtained.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.8581

The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric-bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration.

This paper presents the results of the hygrothermal effect on the impact response of carbon/epoxy composites and the benefits gained from doping the epoxy resin with nanoclays previously subjected to a silane treatment appropriate for the resin. The nanoclay reinforcement increased the maximum load and the elastic recovery of the composites. The thermal degradation caused by exposure to 60°C for 10 days was insignificant, while the immersion in water at 60°C for 30 days led to a continuous reduction in the maximum load and the elastic recovery. Multiple impacts resulted in a continuous and nearly linear degradation of the impact response both of dry and environmentally assisted specimens.

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Much has been discussed about the advantages regarding the thermomechanical performance of self-flow refractory castables (SFRC), with very little or no addition of calcium aluminate cement (CAC) when compared to conventional composites with cement. Previous works demonstrated that a 100% alumina SFRC with optimized particle size distribution simultaneously results in high-flowability fresh paste and high mechanical strength. In this work, the thermomechanical behaviour of zero-cement ceramic matrix is compared to that of the equivalent composite with 1% CAC content. The results show that the differences in performance can be related to differences in hydration mechanisms, namely the formation sequence of calcium aluminate hydrates, which results in increased open porosity. With lower dried strength, the all-alumina castable presents lower porosity, higher mechanical strength and uncompromised thermal shock resistance, being a valuable option when fast drying or rough green handling can be avoided.

In this work, alumina powders in five different commercially available size ranges were used to prepare various refractory castable mixtures, defined using the statistical design of mixture experiments (STATISTICA, StatSoft Inc.) and the EMMA 3.3 software (Elkem Materials). Those mixtures were characterized for packing density, Andreasen particle size distribution modulus ( q ), flowability and after sintering properties, in order to investigate the relationships between these variables. The optimization of matrix and aggregate sizes and matrix-aggregate proportion, subjected to different property requirements, brought to light the relationships between q , specific surface area (SSA) and maximum paste thickness (MPT). Those relationships were investigated for three fundamental processing steps, namely, dry powders, fresh paste and consolidated dried and sintered bodies. The optimized all-alumina castable was found to require 47.5 wt.% of a fine size matrix with high flowability, which provides the necessary flow bed for 52.5 wt.% of coarse aggregates, resulting in a gap-sized particle size distribution, and presented a fresh paste flowability index above 130% with minimum added water (28 mg/m 2 ) and sintered modulus of rupture above 50 MPa.