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A mountain bike carbon reinforced polymeric frame failed in two pieces during cycling over a grass meadow at a speed of about 25 km/h. This has caused the shoulder dislocation of the driver, also last author of this paper. Here, we demonstrate evidence of macroscopic numerous pre‐existing and propagating defects, such as wrinkles, voids and delaminations, resulting in low mechanical properties of this frame. Numerical dynamic simulations conclude the paper and suggest a further cause of frame weakening, due to defect‐resonance interaction. The paper suggests that the design of carbon fiber reinforced plastic frame for mountain bikes may require new scientific and technological advancements for the safety of the riders, at least today carefully eliminating pre‐existing defects and tomorrow proposing bioinspired flaw tolerant solutions. [ABSTRACT FROM AUTHOR]

TNF signaling is an essential regulator of cellular homeostasis. Through its two receptors TNFR1 and TNFR2, soluble versus membrane-bound TNF enable cell death or survival in a variety of cell types. TNF-TNFRs signaling orchestrates important biological functions such as inflammation, neuronal activity as well as tissue de- and regeneration. TNF-TNFRs signaling is a therapeutic target for neurodegenerative diseases such as multiple sclerosis (MS) and Alzheimer’s disease (AD), but animal and clinical studies yielded conflicting findings. Here, we ask whether a sequential modulation of TNFR1 and TNFR2 signaling is beneficial in experimental autoimmune encephalomyelitis (EAE), an experimental mouse model that recapitulates inflammatory and demyelinating aspects of MS. To this end, human TNFR1 antagonist and TNFR2 agonist were administered peripherally at different stages of disease development in TNFR-humanized mice. We found that stimulating TNFR2 before onset of symptoms leads to improved response to anti-TNFR1 therapeutic treatment. This sequential treatment was more effective in decreasing paralysis symptoms and demyelination, when compared to single treatments. Interestingly, the frequency of the different immune cell subsets is unaffected by TNFR modulation. Nevertheless, treatment with only a TNFR1 antagonist increases T-cell infiltration in the central nervous system (CNS) and B-cell cuffing at the perivascular sites, whereas a TNFR2 agonist promotes Treg CNS accumulation. Our findings highlight the complicated nature of TNF signaling which requires a timely balance of selective activation and inhibition of TNFRs in order to exert therapeutic effects in the context of CNS autoimmunity. [ABSTRACT FROM AUTHOR]

The global energy matrix is based on the use of fossil fuels, which are the main contributors of the greenhouse effect. There are several different alternatives to minimize this problem, such as the pelletization of agroforestry wastes for bioenergy purposes. The aim of this research was to evaluate the potential of forest biomass (eucalyptus wood [E]) and agricultural residues of coffee processing (parchment [P], silver skin [S] and coffee husk [C H) for pellets production focusing on the generation of energy and to classify them according to commercialization standards. Different proportions of forest biomass mixed with coffee residues were evaluated and used for the production of the pellets with six compositions (EPC H and EPS). Additionally, three coffee processing residues were individually pelleted (100% pure). The pellets with the composition eucalyptus-parchment-coffee husk (E C PC H) had greater durability (98.17%), hardness (37.12 kg) and net energy density (11.60 GJ m−3), and are eligible for commercialization and export according to European standards (type B). The pellets produced with biomass blends provide better energy results (16.51–17.08 MJ kg−1), compared to pellets produced only with C H (15.76 MJ kg−1) and S (16.26 MJ kg−1). The biomass blends positively influenced the bulk density, mechanical durability, and combustibility of pellets. Image 10468 • Pellets produced with coffee residues met the standards of European. • The use of biomass with good properties, improves the quality of pellet with mixtures. • High percentage of ashes lead to exclusion of raw material to production of pellets. • Pellets produced with coffee residues can compete with wood pellets to generate heat. [ABSTRACT FROM AUTHOR]

The aim of this research is to examine the distribution’s evolution of the industrial sector in the municipalities of Santa Catarina State and its transformations for the years 2002, 2009 and 2016. We used two methodologies to measure the evolution: Principal Component Analysis to build an Industrial Municipal Index (IMI) of Santa Catarina cities, which is used with Spatial Data Analysis. The Moran's I statistics appoint to regions of industrial concentration witch areas are spatially autocorrelated. The results revealed an increase in the IMI average, although in the most industrialized regions there was a reduction, such as in Joinville, Jaraguá do Sul, Blumenau and Brusque. [ABSTRACT FROM AUTHOR]

The worldwide increase in the demand for wood pellets has led to increased interest in the use of biomass feedstock. However, the quality of pellets depends directly on the biomass feedstocks. This paper brings new insights about the influence of lignin distribution, physicochemical characteristics, and microstructure on the quality of pellets. The aim of the study was to characterize the physical, chemical, mechanical and energy properties of pellets produced from Pinus radiata (PR), Eucalyptus nitens (EN), Paulownia elongata × fortune (P), and Miscanthus × giganteus (MG), as well as to use microscopic techniques to examine how lignin distribution influences the mechanical properties. The findings show that the pellets made from PR were more suitable for bioenergy production compared to those produced with EN, P, and MG. Anatomical structure proved to be important in relation to pellet quality. The clear areas on the surface of the pellets presented relationship with the percentage of biomass lignin (which ranged from 26.4 to 34.2%). The P and PR pellets were more durable and had fewer empty spaces between particles. The pellets made from EN, which was the material most difficult to compact, had abundant cracks. Image 1 • Wood, bark and branches of Miscanthus can be used to produce pellets for energy use. • The energy ranking was Pinus radiata > Eucalyptus nitens > Paulownia > Miscanthus. • Cl content is the main factor limiting the quality of Eucalyptus nitens pellets. • High percentages of lignin distributed outside the fibers increase pellet durability. • The uncracked area of the pellets was positively correlated with the lignin content. [ABSTRACT FROM AUTHOR]

This study investigated the self-healing properties of PA6/COC blends, in particular, the impact of three compatibilizers on the rheological, microstructural, and thermomechanical properties. Dynamic rheological analysis revealed that ethylene glycidyl methacrylate (E-GMA) played a crucial role in reducing interfacial tension and promoting PA6 chain entanglement with COC domains. Mechanical tests showed that poly(ethylene)-graft-maleic anhydride (PE-g-MAH) and polyolefin elastomer-graft-maleic anhydride (POE-g-MAH) compatibilizers enhanced elongation at break, while E-GMA had a milder effect. A thermal healing process at 140 °C for 1 h was carried out on specimens broken in fracture toughness tests, performed under quasi-static and impact conditions, and healing efficiency (HE) was evaluated as the ratio of critical stress intensity factors of healed and virgin samples. All the compatibilizers increased HE, especially E-GMA, achieving 28.5% and 68% in quasi-static and impact conditions, respectively. SEM images of specimens tested in quasi-static conditions showed that all the compatibilizers induced PA6 plasticization and crack corrugation, thus hindering COC flow in the crack zone. Conversely, under impact conditions, E-GMA led to the formation of brittle fractures with planar surfaces, promoting COC flow and thus higher HE values. This study demonstrated that compatibilizers, loading mode, and fracture surface morphologies strongly influenced self-healing performance. [ABSTRACT FROM AUTHOR]

This university extension project aimed to evaluate the effectiveness of an educational activity group formed by dyslipidemic patients in relation to nutritional status, intake of fat and fiber and lipid profile. In this study participated 29 individuals, adults and elderly of both sexes. There were two groups: group 1 (n=14), which lasted five months and fortnightly meetings and, group 2 (n=15), three months with weekly meetings. In the first (M0) and penultimate (M1) meeting were applied simplified food frequency questionnaires; measured the height and weight and obtained the values of Body Mass Index (BMI) and; analyzed the serum lipid profile. In 8 and 4 months after the end of the activity of groups 1 and 2, respectively, the subjects underwent the same evaluation again. A total of 16 patients were excluded, totaling 13 participants, mean age 57.5 ± 10.4 years. The weight and BMI remained unchanged during the study. There was a gradual decrease in mean score fat in both groups, but this improvement was only statistically significant from the beginning (M0) to the period after the end of the activity (M2) (group 1, p=0.0303 and group 2, p=0.0008). This modification in fat intake behavior observed in M2 only reflected in the serum lipid profile of group 1 patients, who showed a significant reduction in triglycerides (p=0.0426). Thus, it is observed that educational activities such as these should be encouraged and practiced in the context of health promotion in primary care and should be part of a continuing education program. [ABSTRACT FROM AUTHOR]

Graphical abstract HT LiCoO 2 synthesized using the cathodes of LIBs as raw materials as catalyst for OER. Highlights • Thermal synthesis of HT LiCoO 2 from Co(OH) 2 recycled from spent Li-ion batteries. • HT LiCoO 2 is used as an electrocatalyst for the oxygen evolution reaction. • Cyclic voltammetry and chronoamperometry tests of HT LiCoO 2 for OER. • The activation free energy of the reaction of OER. Abstract Development of novel materials based on inexpensive metals is crucial for renewable energy storage technologies. Furthermore, the recycling of compounds, such as lithium cobaltate (LiCoO 2) from Li-ion battery cathodes, contributes to the recovery of important elements, such as Co and Li. The applicability of high-temperature (HT) LiCoO 2 as a multifunctional material has been tested. In this work, HT LiCoO 2 is used as an electrocatalyst for the oxygen evolution reaction (OER). Cyclic voltammetry and chronoamperometry tests show that the evolution of oxygen starts at 0.35 V accompanied by the formation of Co4+ ions. The activation free energy of the reaction calculated using Tafel plot is 28.0 kJ mol−1 and electrochemical impedance spectroscopy elucidates an equivalent circuit with a transfer charge resistance of 1.55 Ω, Warburg impedance of 150.3 Ω, and constant phase elements of 3.50 and 1.35 m F inside the pores and at the double layer, respectively. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (xGnP), expanded graphite (EG), multiwall carbon nanotubes (MWCNTs), and carbon black (CB) were dispersed in various amounts in a thermosetting polyurethane (PU) matrix derived from castor oil and composite plaques were obtained by compression molding. The electrical percolation threshold was found to be 0.1 vol% for MWCNT, 0.5 vol% for xGnP, 2.8 vol% for CB, and 2.7 vol% for EG‐filled systems. The relation between electrical conductivity, morphology, and electromagnetic interference shielding effectiveness (EMI SE) of the resulting composites was studied to understand how the EMI SE is influenced by morphology and electrical conductivity of each filler. The composites display significantly distinct EMI SE values, depending on the type of carbon filler and its volume fraction. Composite based in PU/EG and PU/xGnP exhibited the highest EMI SE values (70 and 47 −dB, respectively); however, PU/MWCNT composites showed higher EMI SE (24 −dB) value at the same filler content (3 vol%) than the other composite system. POLYM. COMPOS., 40:E78–E87, 2019. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The effects of carbonaceous nanoparticles, such as graphene (GNP) and multiwall carbon nanotube (CNT) on the mechanical and electrical properties of acrylonitrile-butadiene-styrene (ABS) nanocomposites have been investigated. Samples with various filler loadings were produced by solvent free process. Composites ABS/GNP showed higher stiffness, better creep stability and processability, but slightly lower tensile strength and electrical properties (low conductivity) when compared with ABS/CNT nanocomposites. Tensile modulus, tensile strength and creep stability of the nanocomposite, with 6 wt % of GNP, were increased by 47%, 1% and 42%, respectively, while analogous ABS/CNT nanocomposite showed respective values of 23%, 12% and 20%. The electrical percolation threshold was achieved at 7.3 wt % for GNP and 0.9 wt % for CNT. The peculiar behaviour of conductive CNT nanocomposites was also evidenced by the observation of the Joule's effect after application of voltages of 12 and 24 V. Moreover, comparative parameters encompassing stiffness, melt flow and resistivity were proposed for a comprehensive evaluation of the effects of the fillers. [ABSTRACT FROM AUTHOR]

Novel polyvinyl alcohol (PVOH) based biodegradable composites were prepared by a hand lay‐up process using ultrathin beech laminae cut by a specialized planer machine, and the resulting materials were thermo‐mechanically characterized. Density measured showed how the adopted procedure led to laminates having a high porosity degree (about 50% by volume) and an elevated wood concentration (about 80% by weight). In fact, because the wood fibers were perfectly cut (not pressed and abraded), wood porosity was partially filled by the PVOH resin, as documented by field emission scanning electron microscope (FESEM) micrographs. The occlusion of wood porosity by the PVOH matrix resulted to be beneficial for the tensile mechanical properties of the composites. In fact, quasi‐static tensile tests and DMTA analysis revealed how the stiffness (E, E′) and strength (σb) values of the composites both along longitudinal and transversal directions were considerably higher than those of the constituents. On the other hand, the values of the specific energy adsorbed under impact conditions by the composites samples were rather low, if compared to the neat matrix. POLYM. COMPOS., 39:1116–1124, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Manganese oxide was electrochemically synthesized from spent zinc–manganese oxide alkaline batteries. The recycled MnO 2 was then used as electrochemical pseudocapacitors. According to Raman spectroscopy, X-Ray Diffraction and XPS analysis primarily α-MnO 2 films were grown at 25 °C and 80 °C, under galvanostatic conditions (i = 10 mAcm −2 ) and at a charge density of 1.0 Ccm −2 . A charge efficiency of 88.0% was obtained in the anodic electrodeposition of MnO 2 at 25 °C and 80 °C. The effect of temperature on the anodic electrodeposition and the film capacitance was evaluated by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. The α-MnO 2 film grown at 80 °C exhibited a porous surface, and higher specific capacitance of 367.30 F g −1 at 1.0 mV −1 and 386.30 F g −1 at 1.25 A g −1 . The α-MnO 2 film grown at 25 °C showed a specific capacitance of 66.80 F g −1 at 1.0 mV −1 and 127.06 F g −1 at 1.25 A g −1 . [ABSTRACT FROM AUTHOR]

The article presents the discussion on material circularity in rubber products. Topics include crumb rubber being used for the production of rubber-modified-asphalt, playground surfaces, artificial turfs, insulating panels; and principal devulcanization strategies containing chemical, ultrasonic, microwave, biological and thermo-mechanical methods .

In this work, cobalt has been recycled from a spent lithium-ion battery (LIB) to synthetize high-temperature (HT) LiCoO 2 . In the leaching process, the cathode and anode materials are mixed with sulfuric acid and hydrogen peroxide by stirring and heating. The leaching liquor is filtrated to separate the carbon graphite anode. Cobalt hydroxide is precipitated after the addition of potassium hydroxide to the leaching solution. Cobalt hydroxide and lithium carbonate are the precursor materials for the thermal synthesis of HT LiCoO 2 at 800 °C for 5 h. The electrochemical behavior of the synthesized material is tested by cyclic voltammetry and cycling tests; the results indicate intercalation and deintercalation of lithium ions into and from the HT LiCoO 2 structure. The cathode from the spent LIB and the synthesized material are characterized by X-ray diffraction, Raman spectroscopy with mapping, scanning electron microscopy, and transmission electron microscopy. [ABSTRACT FROM AUTHOR]

The main focus of this study is to characterize the interfacial interactions between silica nanoparticles and polypropylene and to investigate how the surface properties and morphology of the silica nanoparticles affect the elastic response of the silica-polypropylene composites. The composites were prepared by melt compounding and injection molding. Both non-functionalized and dimethyldichlorosilane-functionalized silica nanoparticles were used. Three-component composites were also prepared by including selected formulations of both poly(propylene- g-maleic anhydride) copolymer (PPgMA) and different types of silica. It was found that both silica types are nucleating agents for PP and significantly alter its crystallization behavior. A strong correlation between the glass transition temperature ( Tg) and the tensile modulus in silica-PP nanocomposites indicated the presence of a secondary reinforcing mechanism that is the pinning of the polymer chains on the silica surface. The presence of a complex constrained phase, represented by immobilized amorphous and transcrystalline phases, forming at the filler surface, was assessed by modulated differential scanning calorimetry and dynamic mechanical analysis. Finally, the interfacial interactions were correlated to the tensile and viscoelastic properties using the theoretical models proposed by Pukanszky and Sumita et al., respectively, and comparing the predictions of the models to experimental results. POLYM. COMPOS., 37:2018-2026, 2016. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

A cyclic olefin copolymer (COC) matrix was melt compounded with various amounts of fumed silica nanoparticles (1, 3 and 5 vol%) and the resulting materials were foamed through supercritical carbon dioxide. Foams were produced at four different foaming pressures (90, 110, 130, and 150 bar), keeping all other processing parameters constant. The main physical properties of both bulk and foamed samples were investigated in order to assess the role of both nanofiller content and foaming pressure. It was observed that the density values of the foamed materials decreased as the foaming pressure increased and that the presence of nanofillers leads to slightly denser materials. Both scanning and transmission electron microscopy evidenced the presence of filler aggregates on the bulk composites. These aggregates resulted to be elongated along the cell wall direction upon foaming. Dynamic mechanical thermal analysis, quasi-static tensile tests, and creep tests evidenced a positive effect played by nanosilica in improving the stiffness, the strength, and the creep stability of the polymer matrix for all foaming pressures. The application of a theoretical model for closed-cell foams highlighted how the stiffening effect provided by the nanosilica networking is mostly effective at elevated filler amounts and reduced foaming pressure values. [ABSTRACT FROM AUTHOR]

Electrospun mats have been prepared by blending emeraldine base (EB) or DBSA-doped polyaniline (PANI.DBSA) with poly(vinylidene fluoride) (PVDF). In order to understand the effect of doped and undoped PANI on the structure and properties of PVDF/PANI mats, the electrical conductivity, doping degree and morphology of the electrospun mats were investigated. The effect of PANI.DBSA and EB content on the properties of PVDF solution and fibers morphology was investigated. The addition of either doped or undoped PANI increases the viscosity of the PVDF solution, but the ionic conductivity was changed significantly by adding doped PANI. The PVDF/EB fibers manifested a core-sheath structure, while PANI agglomerates were homogeneously distributed in the PVDF/PANI.DBSA. This morphology associated to the high porosity of mat resulted in insulating mats, even when 23 wt% of PANI salt was used and high doping levels were achieved. The PVDF/EB mats obtained from electrospinning displayed a considerable doping level, indicating that the electrical field could induce the protonation of PANI. [ABSTRACT FROM AUTHOR]

The article presents a study that assesses the effect of bandage use on motor performance and pain in people with knee osteoarthritis during obstacle crossing. It measures the vertical and anterior components of the ground reaction force during crossing using a force plate while pain is tested using the visual analogue scale. It is suggested that bandage allows more rapid movements, reduces the overload on the locomotor system, and estimates the force applied against the ground.

Linear low-density polyethylene (LLDPE)-based composites were prepared through melt compounding and hot pressing using both untreated and treated halloysite nanotubes (HNT) up to filler contents of 8 wt% to assess the role of the filler exfoliation and surface treatment on the thermal, mechanical, and rheological properties of the resulting composites. The addition of treated nanoparticles resulted in a better dispersion of the filler within the matrix, as confirmed by observations conducted at scanning and transmission electron microscopies. A decrease in both complex viscosity and shear storage modulus was recorded for all LLDPE-HNT nanocomposites in the molten state. Differential scanning calorimetry analysis evidenced that HNT addition produced an increase of the crystallization peak temperature, while thermogravimetric analysis showed a remarkable improvement of the thermal stability with the nanofiller content. The addition of treated HNT nanoparticles induced better improvements in elastic modulus and tensile properties at break without significant loss in ductility. The fracture toughness, evaluated by the essential work of fracture approach, showed remarkable improvements (up to a factor of 2) with addition of treated HNT. Conversely, incorporation of untreated HNT produced an adverse effect on the fracture toughness when considering the nanocomposite filled with 8 wt% HNT. Both creep tests and dynamic mechanical analyses showed an overall enhancement of the viscoelastic properties due to addition of HNT, revealing higher improvements in nanocomposites added with treated HNT. POLYM. COMPOS., 36:869-883, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The effects of various types and amounts of fumed silica and graphite nanoplatelets on the microstructure and thermomechanical properties of polypropylene composites containing 5, 10, and 20 wt% of short glass fibers have been analyzed. Hybrid composites were produced by melt compounding and compression molding. The aspect ratio of the short glass fiber decreased with the fiber loading and the nanofiller amount. The tensile strength and elastic modulus increased, while the elongation at break decreased as the content of both short glass fiber and nanofiller increased. A two-population model, based on the Halpin–Tsai and Tsai–Pagano composite theories, was used to predict the elastic modulus of the nano-micro hybrid composites. Experimental values appear to be reasonably consistent with model predictions. Tensile energy to break under impact conditions increased with the short glass fiber content but decreased with nanofiller amount. Moreover, storage modulus and creep stability were remarkably enhanced in short glass fiber composites by the presence of both nanofillers. [ABSTRACT FROM AUTHOR]

Nonlinear viscoelastic creep was studied on polypropylene/fumed silica nanocomposites. The free-volume theory of nonlinear viscoelastic creep was successfully applied to obtain generalized creep master curves using a tensile compliance vs. internal time superposition in the region of nonlinear viscoelasticity. Concurrently, a time-temperature superposition approach was also adopted for the construction of creep master curves. A good agreement between the time-strain and the time-temperature superposition approaches was assessed by comparing the master curves obtained from the two data reduction methods. Both approaches evidenced a remarkable stabilizing effect induced by the nanoparticles that was observed especially for higher creep stresses and at increased temperatures and, considering the correspondent superposition principle, at long loading times. At the same time, both storage and loss moduli measured through dynamic mechanical analyses, were enhanced in all nanocomposites. Activation energy values obtained from the analysis of dynamic multi-frequency tests were in good accordance with those referred to creep tests. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the properties of hybrid composites made by epoxy reinforced with short glass fibers (GF) and exfoliated graphite nanoplatelets (GNP) were determined as a function of the GF loading. The addition of GNP, either within the matrix or at the GF surface (GFc), promoted the formation of a stronger GF–epoxy interface, as evaluated by the single-fiber microdebonding test, resulting in an increase of the interfacial shear strength by ∼60% exhibited by the hybrid epoxy composite reinforced with 5wt% GNP. Quasi-static tensile tests and impact tests were performed in order to explore how the combined effect of the nano- and micro- size reinforcements affected the macroscopic mechanical properties under low and high strain rates. The improved tensile modulus, ultimate tensile strength and impact resistance exhibited by the hybrid composites revealed that it is possible to introduce the nano-materials at the fiber/matrix interface and significantly improve the interfacial properties, leading to lighter and stronger composites. Furthermore, the storage modulus and the viscoelastic behavior of GF/epoxy composites were remarkably enhanced upon addition of GNP, indicating strong GNP–polymer interactions and immobilization of the polymer chains. In conclusion, the combined effect of nano-materials and micro-size reinforcements can be exploited to produce light-weight hybrid composites with enhanced mechanical properties. [Copyright &y& Elsevier]

Basalt and E-glass fibers fabrics were combined with carbon fiber fabrics in order to prepare epoxy-based interlaminar hybrid composites and to investigate the hybridization effect on the flexural and impact properties of the resulting laminates. The flexural modulus of the composites depended on their composition according to a rule of mixture, while an important synergistic effect was detected for the ultimate flexural properties. Charpy impact tests evidenced a strength increase as basalt and glass fibers content increased. Interestingly, hybridization with basalt fibers promoted an increase of the adsorbed impact energy due to an enhancement of the fracture propagation component. [ABSTRACT FROM AUTHOR]

Single-polymer short-fibers composites (SPSFCs) were obtained by including Vectran®fibers in a Vectran®matrix. A thermal annealing treatment was optimized to increase the melting temperature, mechanical properties, and thermal stability of pristine Vectran®fibers, and a two-step process was successfully developed to consolidate SPSFCs containing up to 30 wt.% of reinforcement. The composites exhibited a remarkable improvement of the tensile modulus (up to 161%) and a decrease of elongation at break in comparison with the unfilled matrix. A slight decrease of the composites tensile strength was also observed which suggested an investigation of the matrix–reinforcement interfacial adhesion. SEM observations evidenced some pull-out phenomena, indicating a poor interfacial adhesion. A plasma surface treatment on the reinforcing fibers was performed in order to increase the interfacial adhesion in the composites. The results showed an increase of almost 180% in the tensile modulus compared with the unfilled matrix and fiber breakage as main fracture mechanism. [ABSTRACT FROM PUBLISHER]

Abstract: An evaluation of the fibre/matrix interfacial shear strength was performed by the single-fibre fragmentation tests on polypropylene–glass fibre microcomposites filled with various types and amounts of silica nanoparticles. In particular, both non-functionalized and dimethyldichlorosilane-functionalized silica nanoparticles were added up to a weight content of 7%. Moreover, the effect of various amounts of maleic anhydride modified polypropylene (PPgMA) on the fibre/matrix adhesion was also investigated, including some selected formulations containing both PPgMA and silica nanoparticles. Interfacial shear strength was found to remarkably increase (up to a factor of about 5 for a 7wt% content of surface treated nanoparticles) with respect to the case of neat polypropylene matrix. The observed effect was explained by considering that silica nanoparticles increase the work of adhesion of polypropylene with respect to glass, as proven by contact angle measurements in different liquids. In addition, silica nanoparticles promoted a remarkable enhancement of both elastic modulus and creep stability of the selected polypropylene matrix. [Copyright &y& Elsevier]

A linear low density polyethylene matrix was melt compounded with a given amount (2 vol.%) of both untreated (hydrophilic) and surface treated (hydrophobic) fumed silica nanoparticles with the aim to investigate the influence of the time under processing conditions on the microstructure and thermo-mechanical properties of the resulting materials. Crosslinking reactions induced by thermal processing caused a remarkable increase of the melt viscosity, as revealed by the melt flow index values of both neat matrix and nanocomposites. Thermal oxidation of the matrix was slightly reduced by the introduction of fumed silica nanoparticles, especially for long compounding times. Differential scanning calorimetry evidenced how silica nanoparticles had a nucleating effect on the matrix, while both the melting temperature and the relative crystallinity were decreased by the compounding process. Nanosilica addition promoted a general improvement of the tensile properties, that progressively decreased with the processing time. [ABSTRACT FROM AUTHOR]

This paper suggests a new interpretation of Ulysses' expression 'di retro al sol' in Inf. xxvi.117, based on the astronomic and poetic heritage of Antiquity. Instead of the usual interpretation of the phrase as 'westwards', it is possible to consider this indication as a reference to the annual pathway of the sun, and to infer that it means 'beyond the tropic of Capricorn'. The hypothesis is reinforced by the interpretation of a similar expression found in Virgil's Aeneid. Petrarca's development of the theme of the Antipodes is also considered. [ABSTRACT FROM AUTHOR]

Fabrics of basalt (BFs), E-glass (GFs), and carbon (CFs) fibers with the same areal density were used to prepare epoxy-based laminates. The BF laminates presented elastic moduli and strength values higher than those of the corresponding GF laminates, with tensile strength values near to that of CF laminates. Investigation of the behavior under fatigue conditions indicated superior performances of BF laminates with respect to the corresponding GF composites, with an improved capability of sustaining progressive damaging and slightly higher damping properties. As far as the fatigue behavior is concerned, BFs may therefore represent a valid substitute of GFs in structural composites. [ABSTRACT FROM AUTHOR]

High-density polyethylene-based nanocomposites were prepared through a melt compounding process by using surface functionalized fumed silica nanoparticles in various amounts, in order to investigate their capability to improve both mechanical properties and resistance to thermal degradation. The fine dispersion of silica aggregates led to noticeable improvements of both the elastic modulus and of the stress at yield proportionally to the filler content, while the tensile properties at break were not impaired even at elevated filler content. Thermogravimetric analysis showed that the selected nanoparticles were extremely effective both in increasing the decomposition temperature and in decreasing the mass loss rate, even at relatively low filler loadings. The formation of a char enriched layer, limiting the diffusion of the oxygen through the nanofilled samples, was responsible of noticeable improvements of the limiting oxygen index, especially at elevated silica loadings. In contrast with commonly reported literature results, cone calorimeter tests also revealed the efficacy of functionalized nanoparticles in delaying the time to ignition and in decreasing the heat release rate values. Therefore, the addition of functionalized fumed silica nanoparticles could represent an effective way to enhance the flammability properties of polyolefin matrices even at low filler concentrations. [ABSTRACT FROM AUTHOR]

An alternative route for the production of graphene-polymer nanocomposites is proposed. First graphene oxide lamellae are homogenously dispersed in a polyvinyl alcohol matrix. In a second step, mild thermal treatments are carried out on composites in order to promote a thermal reduction of the graphene oxide into reduced graphene oxide. The occurrence of an in situ reduction of graphene oxide is confirmed by various experimental techniques, such as differential scanning calorimetry, thermogravimetric analysis and electrical resistivity measurements. [ABSTRACT FROM AUTHOR]

The microstructure and thermomechanical behaviour of a novel fully biodegradable polyvinyl alcohol (PVOH)-based single-polymer composite (SPC) is presented. Three kinds of PVOH stapled fibres, having different melting temperatures and tensile mechanical properties, were considered as a reinforcement, whilst plasticized PVOH granules were selected as a continuous matrix. Calorimetric tests on the constituents showed significantly different melting temperatures between the matrix and the fibres, thus evidencing adequate processing windows for the preparation of SPCs. On the other hand, scanning electron microscopy on the cryofractured surfaces of melt-mixed and compression-moulded SPCs experimentally proved that the morphological integrity of the reinforcement was maintained only when high melting temperature fibres were utilized. Quasi-static mechanical tensile tests highlighted the capability of the selected PVOH fibres to remarkably increase the elastic modulus, the stress at yield and the Vicat softening temperature of the PVOH matrix. Moreover, dynamic storage modulus and glass transition temperature of SPC increased with respect to the neat PVOH over the whole range of considered temperatures, whilst short-term creep stability was strongly improved, proportionally to the fibre content. The application of a time-temperature superposition principle to creep data confirmed the effectiveness of these fibres in increasing the long-term creep stability of the resulting materials. [ABSTRACT FROM AUTHOR]

Abstract: The role of fumed silica nanoparticles, having different surface area and surface treatments, on the fracture behaviour of a linear low density polyethylene (LLDPE) matrix was investigated. Tensile tests under quasi-static and impact conditions evidenced beneficial effects on both the elastic modulus and the strain at yield. By the essential work of fracture approach, increments of both the initiation and the propagation components of the specific essential work of fracture terms were highlighted. Dilatometric measurements excluded the filler–matrix debonding as a possible toughening mechanism, while a progressive alignment of silica aggregates was detected by TEM observations. [Copyright &y& Elsevier]

Abstract: Two nanosized carbonaceous fillers, vapor grown carbon nanofibers and exfoliated graphite nanoplatelets, were used to prepare poly(lactide acid) composites at various concentrations from 0 up to 20wt.%. The two fillers were also combined in order to explore possible synergistic actions. Two compounding processes, melt mixing and polymer dissolution, and two forming methods, injection and compression molding, were used to manufacture the composites. The flexural properties, impact strength, storage and loss modulus, Vicat softening temperature, and electrical conductivity of neat matrix and composites were determined as a function of the filler type and content, and of the processing method used. The filler dispersion within the polymer matrix, the presence of agglomerates and the existence of voids were studied using field-emission scanning electron microscopy. It is concluded that compounding by polymer dissolution followed by compression molding leads to composites with the lowest percolation threshold and surface conductivity and highest storage modulus whereas extrusion injection molding results in composites with the highest mechanical properties. The results can be used to engineer biodegradable composites with specific properties for targeted applications. [Copyright &y& Elsevier]

The viscoelastic nature of the Poisson's ratio of a semicrystalline poly (butylene terephthalate) is highlighted by investigating its dependence on time, temperature and strain rate, under two types of loading conditions: i) constant deformation rate tests, in which the transverse strain is measured in tensile ramps at various temperatures and at two strain rates; and ii) constant deformation tests, in which, under a constant axial deformation, the transverse strain is measured as a function of time in isothermal experiments performed at various temperatures. In both testing configurations, axial and transverse deformations are measured by means of a biaxial contact extensometer, and a correction procedure is adopted in order to compensate the lateral penetration of the extensometer knives. Poisson's ratio displays the typical features of a retardation function, increasing with time and temperature, and decreasing with strain rate. This behaviour has been compared to that of simultaneously measured relaxation modulus. [ABSTRACT FROM AUTHOR]

Abstract: Microstructural and thermo-mechanical characterization were performed on epoxy–clay nanocomposites, to be used as matrix for continuous carbon fiber reinforced composites, containing various amounts of clays having different hydrophilicity. XRD tests displayed that the dispersion degree of the clay lamellae was strictly correlated to their hydrophilicity, while DSC tests revealed that the crosslinking degree was negatively affected by the presence of most hydrophilic clays. Therefore, the balance between polymer–filler interaction and crosslinking degree influenced the final properties of the resulting composites. The mechanical behaviour, both under quasi-static and impact conditions, was positively affected by resin nanomodification. Fracture toughness and threshold to crack initiation under cyclic loading were also interestingly improved. While the effect of nanoclay introduction on the quasi-static tensile properties of the carbon/epoxy laminates was negligible, Charpy impact tests on nanomodified epoxy/carbon fiber cross-ply laminates evidenced slight enhancements of the elastic modulus and of the energy adsorption capacity with respect to the unfilled epoxy–carbon composites. Moreover, drop weight test on laminates evidenced improvements in energy absorption capacity due to resin nanomodification. [Copyright &y& Elsevier]

Both untreated and calcined fumed alumina nanoparticles were dispersed into an epoxy-based adhesive at various percentages. The glass transition temperature of the nanofilled adhesives increased up to an optimal filler loading and then decreased, probably due to concurrent and contrasting effects of chain blocking and reduction of the crosslinking degree. Tensile modulus, stress at break, and fracture toughness of bulk adhesive were positively affected by the presence of untreated alumina nanoparticles at an optimal filler content. Mechanical tests on single-lap aluminum bonded joints indicated that untreated alumina nanoparticles markedly improved both the shear strength and fatigue life of the bonded joints. In particular, the shear strength increased by about 60% for an optimal filler content of 1 vol.%, and an adhesive failure mechanism was evidenced for all the tested specimens. Concurrently, a relevant decrease of the equilibrium contact angle with water was observed for nanofilled bulk adhesives. In summary, alumina nanoparticles can effectively improve the mechanical performances of epoxy structural adhesives, both by increasing their mechanical properties and by enhancing the interfacial wettability with an aluminum substrate. [ABSTRACT FROM AUTHOR]

Thin transparent films of polyurethane—clay nanocomposites were prepared by dispersing different amounts of commercial organo-modified clay in a mixture of cycloaliphatic amines used as chain extender of a blocking prepolymer, in order to investigate the role of the filler content on the thermo-mechanical behavior of the resulting composites. X-ray diffraction measurements evidenced the formation of an intercalated structure, regardless to the clay loading. Furthermore, the optical clarity of the samples was not substantially compromised by the nanofiller addition even at elevated clay amounts. Interestingly, the relatively strong polymer—filler interaction led to a substantial reduction of the matrix crosslinking degree for high clay loadings. Consequently, the relative thermal lifetime was positively affected by the presence of clay up to a filler content of 7 wt%, while uniaxial tensile tests under quasi-static and impact conditions evidenced an increase of the elastic modulus proportional to the clay concentration, without impairing the original tensile properties at break. [ABSTRACT FROM PUBLISHER]

Linear low density polyethylene (LLDPE) was melt compounded with various amounts of a cycloolefin copolymer (COC). Scanning and transmission electron microscopy evidenced, at qualitative level, some interfacial adhesion between LLDPE and COC. Another indication of interactions between the components was the increase of crystallinity degree with rising COC content and the enhancement of COC glass transition temperature with the LLDPE fraction. In order to explain this behaviour, the incorporation of ethylene segments of COC into the LLDPE crystalline phase, leading to an increased number of norbornene units in the remaining COC component undergoing the glass transition, was hypothesized. The thermo-oxidative degradation stability of LLDPE was substantially enhanced by COC introduction for filler contents higher than 20 wt%, especially when an oxidative atmosphere was considered. An increasing fraction of COC in the blends was responsible for an enhancement of the elastic modulus and of a decrease in the strain at break, while tensile strength passed through a minimum, in agreement with the model predictions based on the equivalent box model and equations provided by the percolation theory. The introduction of a rising COC amount in the blends increased the maximum load sustained by the samples in impact tests, but decreased the blend ductility. Concurrently, a significant reduction of the creep compliance of LLDPE was observed for COC fractions higher than 20 wt%. [ABSTRACT FROM AUTHOR]

Zirconia nanoparticles were synthesized by a sol-gel route and dispersed into an epoxy base for structural adhesives. Nanoparticles were used as-synthesized or after calcination. Moreover, the effect of silane functionalization was also investigated. According to preliminary tensile mechanical tests on bulk nanocomposite samples, calcined and untreated zirconia nanoparticles were selected for the preparation of adhesives with various filler contents. The glass transition temperature increased up to a filler content of 1 vol% and then decreased, probably due to the concurrent and contrasting effects of chain blocking and reduction of the crosslinking degree. Also tensile modulus, stress at break and fracture toughness of bulk adhesives samples were positively affected by the presence of an optimal amount of zirconia nanoparticles. Mechanical tests on single lap aluminium bonded joints indicated that zirconia nanoparticles led to relevant enhancements of the shear strength of the joints. In particular, the shear strength increased by about 60% for an optimal filler content of 1 vol%, and an adhesive failure mechanism was evidenced for all the tested specimens. Concurrently, a significant decrease of the equilibrium contact angle with water was observed for adhesives containing zirconia nanoparticles. It can therefore be concluded that the addition of zirconia nanoparticles can effectively improve epoxy adhesives, both by increasing their mechanical properties and by enhancing the interfacial wettability with an aluminium substrate. [ABSTRACT FROM AUTHOR]

Abstract: The chemical preparation of a tin-doped spinel ferrite via the co-precipitation method rendered a sample containing 48.2mass% Fe3+, 11.8mass% Fe2+ and 13.0mass% Sn. Powder X-ray diffractometry data collected with synchrotron radiation source revealed the co-existence of two crystallographic phases: one with cubic (spatial group, Fd3m) spinel and other with trigonal–hexagonal () structure. 57Fe Mössbauer spectroscopy analysis confirmed the occurrence of two tin-doped phases, with relative spectral areas of 50.6% and 49.4%; deduced chemical structures of these two phases correspond to and , (⊕, cation vacancy), respectively. The measured value for saturation magnetization σ =30JT−1 kg−1 for this sample leads to a Sn4+-ferrite with σ =60JT−1 kg−1. The magnetic hyperfine field detected with 119Sn Mössbauer spectroscopy was interpreted as being due to a supertransferred magnetic moment from iron cations to Sn4+ in octahedral sites of these iron oxides lattices. [ABSTRACT FROM AUTHOR]

Abstract: The annealing treatment of drawn LCP nanocomposite monofilaments is discussed here. Upon annealing, an unstable structure is generated which presents a strong dependence on the annealing time sequence and temperature as observed by DSC. Moreover, it seems that increasing the draw down of the fiber restricts the formation of this new (unstable) structure. Based on dynamic mechanical analysis and on solid state 13C NMR, the nature of the newly-formed structure is elucidated, and based on sequence ordering within the non-oriented amorphous phase in the copolymer, a 10% change in the monomer proportion in the ordered phase is observed after annealing. [Copyright &y& Elsevier]

Abstract: The precision (i.e. the repeatability) of the essential work of fracture (EWF) method in determining the fracture parameters of a highly extendible linear low-density-polyethylene film is investigated. In order to minimize any interference from external variables, a random data collection procedure is adopted to extract, from a large data set, various EWF samples with sizes ranging from 11 to 150 data points. Two different notching procedures have been considered, involving different tools (scalpel or razor blade) and cutting methodologies. The notching procedure has only a marginal influence in terms of the correlation coefficient of the linear regression and standard error on the specific essential work of fracture (w e). However, the mean of w e values is markedly affected by the notching procedure, being its influence on the specific non-essential work of fracture (βw p) parameter relatively lower. The dispersion of the w e and βw p data around their mean values decreases as the sample size increases, with a trend clearly affected by the notching procedure. [Copyright &y& Elsevier]

Objective.— To contrast the cervical range of motion (CROM) in women with episodic migraine (EM), transformed migraine (TM), and controls without migraine headaches. Background.— Migraineurs often complain about neck pain. Furthermore, neck problems can worsen the headaches in individuals with migraine. Individuals with neck pain usually have reduced CROM. Nonetheless, studies assessing the CROM in migraineurs are scarce. Methods.— Our sample was selected in an outpatient headache clinic, and consisted of 45 women aged 20-54 years old, 15 per group. Cervical mobility was evaluated in movements of flexion, extension, right lateral flexion, left lateral flexion, right rotation, and left rotation using the CROM technique, and was contrasted among the groups. Migraine clinical patterns were also evaluated (frequency, duration of migraine, pain in the moment of evaluation, pain in movement, and pain localization) as a function of CROM. Results.— Compared with controls, individuals with TM had numerically inferior CROM in all parameters, and significant reduction in 3 of them: extension (59.3 vs 68.1, P = .02), left lateral flexion (44.5 vs 49.1, P = .03), and right rotation (62.2 vs 69.6, P = .02). Compared with individuals with migraine, the TM group presented significantly reduced mobility only for extension (59.3 vs 68.4, P = .02). Migraineurs also had numerically inferior ROM, contrasted to controls, in 5 of the 6 parameters, although significance was seen just for right rotation (60.8 vs 68.6 P < .01). There was no correlation between cervical mobility and migraine parameters. The CROM was not reduced for the symptomatic side of migraine, in cases of unilateral pain. Conclusion.— Contrasted to controls, individuals with episodic and TM have decreased cervical range of motion. [ABSTRACT FROM AUTHOR]

The effect of the deformation temperature on the energy stored in post-yield deformed poly(butylene terephthalate) PBT, was studied by means of DSC tests. Deformed specimens were rapidly cooled after unloading, in order to avoid the energy relaxation processes occurring before the DSC measurements. Cooling revealed to have a significant contribution on the whole stored energy, as shown by DSC tests conducted on undeformed PBT specimens conditioned at various temperatures. This work is aimed at separating the effects due to cooling and those ascribed to deformation on the energy storage and release processes, permitting to better understand previous findings on post-yield compressed PBT. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the correlation between interlaminar fracture toughness and impact energy absorption for the fracture of epoxy–carbon laminates was studied. Carbon fibres–epoxy cross-ply prepreg layers were interleaved with thin (26μm) poly(ethylene-terephthalate) (PET) films. Before the composite preparation, circular holes 1mm in diameter were drilled in the PET films at several densities (from 0 up to 44holes/cm2) in order to selectively increase the interlaminar contact area between the epoxy–carbon laminae. In this way, the interlaminar contact area was gradually varied from 0%, corresponding to the case in which non-perforated PET films were used, up to 100% in the case of non-interleaved laminates. The Mode I interlaminar fracture toughness of the resulting laminates was determined according to the ASTM D-5528-01 standard test method on double cantilever beam (DCB) specimens. The critical values of the strain energy release rate determined at the point at which the load versus opening displacement curve becomes non-linear (G IC,NL) resulted to vary from 40 up to 260J/m2, depending on the interlaminar contact area. All the laminates were then characterized by three point bending tests performed both under quasi-static (5mm/min) and impact (2m/s) loading conditions. The elastic modulus of the laminates resulted to be practically independent of the level of interlaminar adhesion, while the bending strength decreased as the interlaminar fracture toughness decreased. The total energy to fracture evaluated under impact conditions showed a non-monotonic correlation with the interlaminar fracture toughness, reaching a maximum level in correspondence of a G IC,NL value of about 60J/m2. At the same time, the ductility index, i.e. the ratio between the propagation and the initiation energies, evaluated by instrumented Charpy impact tests, markedly increased as the interlaminar fracture toughness decreased. [Copyright &y& Elsevier]

Abstract: The Boltzmann superposition principle (BSP) valid for “standard linear solids” is presented in all textbooks on viscoelasticity. In practice, the BSP is not applicable to viscoelastic polymers because (i) the apparent limit (if any) of the stress–strain linearity is very low, (ii) real deformations (stresses) are not infinitesimal, and (iii) tensile deformations give rise to additional free volume, which affects all currently running deformation processes. Consistent application of the free volume approach, including the strain-induced free volume, allowed us to derive and verify a new type of the internal time–tensile strain superposition for a series of single-step nonlinear creeps [J. Kolařík, A. Pegoretti, Nonlinear tensile creep of polypropylene: time–strain superposition and creep prediction, Polymer 47 (1) (2006) 346]. The Boltzmann-like superposition principle for multistep nonlinear tensile creep, proposed in this paper, consists of (i) the separation of individual creeps, (ii) their reconstruction for the initial free volume by introducing a specific internal time, and (iii) the superposition of the reconstructed creeps. The procedure is demonstrated using creep data for three types of commercial polypropylene. [Copyright &y& Elsevier]

Abstract: Optically transparent polyurethane-clay nanocomposite films were prepared by dispersing 5wt% of various commercial organo-clays in a mixture of cycloaliphatic amines used as chain extender-cross-linker of a blocked prepolymer. For the first time, vibration-induced equilibrium contact angle measurements were successfully employed to rank the selected organo-clays accordingly to their hydrophobicity order. Polymer–clay intercalation degree in the nanocomposites, as assessed from X-ray diffraction, was strongly correlated to the water–clay equilibrium contact angle. Moreover, as the clay intercalation degree increased, a decrease of the cross-linking degree of the polyurethane matrix occured. Uniaxial tensile tests under quasi-static and impact conditions, and isothermal thermogravimetric analysis were performed on both unfilled polyurethane matrix and nanocomposites. Secant tensile modulus, tensile energy to break, and thermal lifetime showed a non monotonic trend with a maximum as a function of the intercalation degree. This behaviour is discussed considering that two concomitant and contrasting effects develop as the polymer–clay intercalation degree increases: a positive improvement of the filler matrix interactions, and a negative reduction of the matrix cross-linking degree. [Copyright &y& Elsevier]

Abstract: The cathode of spent Zn-MnO2 primary batteries is made up of mainly Mn3O4 and α-MnO2. Energy dispersive X-ray analysis of the cathode surface also shows the presence of zinc from the anode and chloride from the electrolyte. Manganese was recovered by precipitation, electrodeposition and anodization. X-ray diffraction measurements confirmed that the Mn3O4 material was recycled by chemical precipitation. The charge efficiency by electrodeposition was 85% at 25.0mAcm−2. In the current density range studied, the potential/current density plots follow a Tafel-like relation. In the anodic process, the material oxidizes at the electrode/solution interface and precipitates to the bottom of the cell. Only a fraction corresponding to 20% of the charge density is deposited onto the electrode. This happens because Mn2+ oxidizes to Mn3+, which then suffers disproportionation. [Copyright &y& Elsevier]

Abstract: Essential work of fracture (EWF) tests have been conducted on neat and rubber toughened polyamide-66 in order to measure the essential specific work of fracture (w e) and the non-essential specific work of fracture (βw p) parameters. Further, the w e value has been partitioned into two terms, one related to the specific energy contribution for yielding up to the onset of fracture (w e,init), and another one representing the subsequent crack propagation process (w e,prop), respectively. EWF tests performed on neat polyamide-66 specimens conditioned up to various equilibrium moisture contents clearly indicate that w e markedly increases as the material moisture content rises, and that this trend is mainly associated with the increase of its crack propagation component (w e,prop), the initiation related term (w e,init) being practically independent of the humidity level. The inclusion of various amounts (7, 16, and 25wt%) of rubber particles (a random ethylene–acrylic ester–maleic anhydride terpolymer) into the polyamide-66 matrix induces a large increase of the w e parameter. It is interesting to observe that the w e,init and w e,prop terms display different trends with the rubber content. Most of the toughening effect of the rubber particles can be attributed to a large increase of the propagation-related term, the fracture initiation term decreasing with the rubber content. Finally, the loading rate effects on the fracture behaviour have been investigated for polyamide-66 toughened with 25wt% rubber. An increase of the loading rate causes an increase of the crack-initiation related term w e,init, while the crack-propagation related parameter w e,prop decreases. As a consequence, the specific term w e shows a non-monotonic trend with the loading rate. [Copyright &y& Elsevier]

In the analysis of a newspaper page an important step is the clustering of various text blocks into logical units, i.e., into articles. We propose three algorithms based on text processing techniques to cluster articles in newspaper pages. Based on the complexity of the three algorithms and experiments on actual pages from the Italian newspaper L'Adige, we select one of the algorithms as the preferred choice to solve the textual clustering problem. [ABSTRACT FROM AUTHOR]