431 research outputs found
Perception of Interpersonal Behaviors Across Cultures
No full textCross-cultural psychology has played a very important role in identifying, describing, and even explaining psychological structures that are involved in the perception of interpersonal behavior. This chapter reviews work based on the research paradigm of subjective culture, which establishes that at least three interpersonal dimensions have been identified across cultures and historical periods: Association-Dissociation, Superordination-Subordination, and Intimacy-Formality. These three dimensions are often conceptualized as psychological universals, a notion that raises the question of the origins of the dimensions. By starting with the fundamental assumption that all social behavior is based on resource exchange, the chapter reviews a framework that attempts to account for the emergence of social meanings through time
Shear strength of furfurylated, N-methylol melamine and thermally modified wood bonded with three conventional adhesives
No full textThe shear strength of furfurylated, N-methylol melamine (NMM) and thermally modified wood bonded with emulsion polymer isocyanate, polyvinyl acetate (PVAc), and polyurethane (PU) adhesives was examined. Furfurylation and NMM modification of Scots pine had a significant negative effect on the bonding strength with all adhesives irrespective of the treatment intensity. The obtained low-shear strength values were related to the brittle nature of the wood after modifications rather to the failure of the bondline. PVAc showed a better bonding performance with both furfurylated and NMM modified wood while the combination of furfurylated wood and PU gave the highest reduction in bonding strength (47–51%). Shear strength also decreased significantly after thermal modification in both Scots pine (36–56%) and beech (34–48%) with all adhesives. With the exception of thermally modified beech samples bonded with PU, bondline was found to be the weakest link in thermally modified wood as it was revealed by the wood failure surfaces. Bondline thickness and effective penetration of adhesives did not relate to the shear strength of all modified wood materials. The lower shear strength of modified wood could be attributed to other factors, such as the reduced chemical bonding or mechanical interlocking of adhesives, and the reduced strength of brittle modified wood substrate.</p
Gross adhesive penetration in furfurylated, N-methylol melamine-modified and heat-treated wood examined by fluorescence microscopy
No full textThis study investigated the radial penetration of three conventional cold-set wood adhesives [emulsion polymer isocyanate (EPI), poly (vinyl acetate) (PVAc), one-component polyurethane (PU)] into various degrees of furfurylated and N-methylol melamine-modified (NMM) Scots pine, and heat-treated Scots pine and beech based on measurements of effective (EP) and maximum penetration (MP) from microscopic observations. EP of EPI adhesive decreased after modification with higher concentration of furfuryl alcohol while an improved penetration was recorded for PVAc into furfurylated wood. A deeper penetration was observed for all adhesives into wood treated with lower concentration of furfuryl alcohol. The EP of EPI and PU adhesives reduced after NMM treatment but it increased in the case of PVAc. In spite of reduction of EP of PU after NMM treatment, it represented a deeper penetration among all adhesives possibly due to its lower molecular weight. For Scots pine, increasing the treatment temperature improved EP of all adhesives while for beech, the EP of PU and PVAc increased largely in the case of samples treated at 195 °C. Visual analysis of fluorescence microscopy pictures provided more detailed information on modality of penetration. The results are useful for understanding the interaction among common adhesives and modified materials, and can be used in future research to explain the bonding behavior of modified wood.</p
(INVITED) Solution Processed High-k Dielectrics for Thin Film Transistors Employing Metal Oxide-based Semiconducting Channels
No full textWhilst progress on solution-processed oxide semiconductors has been rapidly advancing, research efforts towards the development of dielectric materials has been relatively slow, with most of the reported work performed using conventional dielectrics based on SiO2 that usually results in high voltage transistor operation and hence increased power consumption. This ever increasing demand for high performance thin film transistors based on metal oxide channels has given a boost to the development of alternatives to SiO2 gate dielectrics with desirable characteristics in terms of thermal stability, band offsets and interface quality. To that end and among the different approaches, the use of high-k dielectrics is arguably the most attractive option, since it can enable low leakage currents, through the use of physically thicker films, as well as low-voltage operation. This work reports on the structure and properties of a wide range of solution-processed binary and ternary gate dielectrics and their implementation in TFTs employing n and p type metal oxide-based semiconducting channels. It mainly focuses on the band offsets, dielectric and optical as well as the dielectric/semiconductor interface properties and their effects on the device operation. References: 1. M. Esro, R. Mazzocco, G. Vourlias, O. Kolosov, A. Krier, W. I. Milne and G. Adamopoulos, Solution processed lanthanum aluminate gate dielectrics for use in metal oxide-based thin film transistors, Appl. Phys. Lett. 106, 203507, 2015 2. M. Esro, S. Georgakopoulos, H. Lu, G. Vourlias, A. Krier, W. I. Milne, W. P. Gillin and G. Adamopoulos, Solution processed SnO2:Sb transparent conductive oxide as an alternative to indium tin oxide for applications in organic light emitting diodes, J. Mater. Chem. C, 4, 3563, 2016. 3. D. Afouxenidis, R. Mazzocco, G. Vourlias, P. J. Livesley, A. Krier, W. I. Milne, O. Kolosov and G. Adamopoulos, ZnO-based thin film transistors employing aluminum titanate gate dielectrics deposited by spray pyrolysis at ambient air, ACS Appl. Mater. Inter., 7, 7334, 2015. 4. M. Esro, G. Vourlias, C. Somerton, W. I. Milne and George Adamopoulos, High mobility ZnO thin film transistors based on solution-processed hafnium oxide gate dielectrics, Adv. Funct. Mater., 25, 134, 2015
Water uptake and wetting behaviour of furfurylated, <em>N</em>-methylol melamine modified and heat-treated wood
No full textThis study reports on the water uptake (WU) and wetting properties of different modified wood materials; furfurylated and N-methylol melamine (NMM) modified Scots pine, and heat-treated (Vacu3 method) Scots pine and beech. All modifications caused a substantial reduction in WU in the longitudinal, tangential and radial directions both after short (24 h) and long contact times (168, 336 h) with a saturated sponge. The water uptake coefficient (w t ) was reduced by approximately 71–89 % in furfurylated wood, with the higher weight percent gain (WPG) providing a slightly greater reduction. The reduction in WU was not found to depend on the NMM solid content. The NMM treatment had the maximum effect on the reduction of tangential w t by 80–84 % and was much smaller in the longitudinal direction (31–68 %). The treatment temperature of 195 °C gave lower WU values than treatment at 210 °C, and the only exception was the radial direction of Scots pine. The longitudinal w t of heat-treated beech represented the highest reduction by 81–89 %, while radial w t was less affected in both species. Sessile drop apparent contact angles for water and diidomethane and corresponding surface energies on planed tangential and radial wood surfaces revealed an increased hydrophobicity and reduced polarity of modified wood. Furfurylated and NMM modified tangential surfaces had a higher increase of apparent contact angles than the radial surfaces but this was not observed in the case of heat treatment. Heat-treated wood showed reduced wetting of surfaces only with water. Apparent contact angles did neither differ with treatment temperature nor with the NMM resin load. The disperse component of surface energy was slightly increased by 20 % maximum in modified wood, while the polar components showed a dramatic decrease by −30 to −90 % with no major differences among treatments and intensities, and between surfaces. The results provide a better understanding of the hygroscopic behaviour of modified wood, which might be useful to predict its adhesion with various polymers such as glues, coatings and paints.</p
‐Methylol melamine and 1,3‐dimethylol‐4,5‐dihydroxyethyleneurea
No full textThe main objective of this study was to assess the effect of two amino resins, N-methylol melamine (NMM) and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU), on the intrafiber and interfiber strengths and water absorption of two types of waste paper categories, office paper (OP), and old corrugated containers (OCCs). The tensile strength of individual fibers measured at zero span was reduced by increases in the resin concentrations. The dry tensile strengths of the recovered handsheets measured at a finite span were enhanced with increases in the weight percentage gain of the resins. The increasing of the resin concentration also significantly improved the intrabonding of the OP and OCCs in moist measuring conditions. The water absorption of the handsheets considerably decreased at the higher concentration of the thermosetting resins, especially with NMM. The results are promising for the use of NMM- and DMDHEU-treated recovered fibers as an alternative fiber resource for the production of laminated paper and also for the use of DMDHEU as a new N-methylol compound for laminated paper. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41290
(INVITED) Solution Processed SiO2 and high-k Dielectrics for MO-based CMOS TFTs
No full textWhilst progress on solution-processed oxide semiconductors has been rapidly advancing, research efforts towards the development of dielectric materials has been relatively slow, with most of the reported work performed using conventional dielectrics based on thermally grown SiO2. Silicon dioxide is the most widely used dielectric material for optical and electronic applications. The SiO2 has been produced by thermal oxidation of silicon, plasma enhanced chemical vapour deposition, sputtering, electron beam evaporation, atomic layer deposition etc. The conventional production of SiO2 by thermal oxidation by necessity requires the use of Si as the substrate and the other methods either produce low quality/poor interface material and/or require high deposition temperatures (>700 oC). The first part of the present work reports on the deposition and characterisation of SiO2 gate dielectrics grown by spray coating in air at moderate temperatures i.e. 350 oC from SiCl4 solutions in pentane-2,4-dione (0.1 M). The films were investigated by means of x-ray diffraction, XPS, UFM/AFM, admittance spectroscopy, UV-Vis absorption spectroscopy, spectroscopic ellipsometry and field-effect measurements. Analyses reveal smooth films (RRMS< 1 nm) of amorphous phase with dielectric constant of 3.8, optical band gap of 8.1 eV and leakage currents of 10-7 A/cm2 at 1 MV/cm. Both XPS and FTIR measurements further confirmed SiO2 structures. Thin film transistors based on thermally grown C60 and pentacene semiconducting channels employing both spray coated as well as thermally grown SiO2 gate dielectrics exhibit identical transport characteristics in terms of hysteresis, leakage currents, carrier mobility and on/off current modulation ratio. However, TFTs employing SiO2 gate dielectrics, usually require high voltage operation and hence increased power consumption. The ever increasing demand for high performance thin film transistors based on metal oxide channels has given a boost to the development of alternatives to SiO2 gate dielectrics with desirable characteristics in terms of thermal stability, band offsets and interface quality. To that end and among the different approaches, the use of high-k dielectrics is arguably the most attractive option, since it can enable low leakage currents, through the use of physically thicker films, as well as low-voltage operation. Thus the final part of the presentation will report on the structure and properties of a wide range of solution-processed binary and ternary gate dielectrics and their implementation in TFTs employing - similarly solution processed n and p type metal oxides semiconducting channels. It will focus on the band offsets, dielectric and optical as well as the dielectric/semiconductor interface properties and their effects on device operation. References 1. M. Esro, R. Mazzocco, G. Vourlias, O. Kolosov, A. Krier, W. I. Milne and G. Adamopoulos, Solution processed lanthanum aluminate gate dielectrics for use in metal oxide-based thin film transistors, Appl. Phys. Lett. 106, 203507, 2015 2. M. Esro, S. Georgakopoulos, H. Lu, G. Vourlias, A. Krier, W. I. Milne, W. P. Gillin and G. Adamopoulos, Solution processed SnO2:Sb transparent conductive oxide as an alternative to indium tin oxide for applications in organic light emitting diodes, J. Mater. Chem. C, 4, 3563, 2016. 3. D. Afouxenidis, R. Mazzocco, G. Vourlias, P. J. Livesley, A. Krier, W. I. Milne, O. Kolosov and G. Adamopoulos, ZnO-based thin film transistors employing aluminum titanate gate dielectrics deposited by spray pyrolysis at ambient air, ACS Appl. Mater. Inter., 7, 7334, 2015. 4. M. Esro, G. Vourlias, C. Somerton, W. I. Milne and George Adamopoulos, High mobility ZnO thin film transistors based on solution-processed hafnium oxide gate dielectrics, Adv. Funct. Mater., 25, 134, 2015
Decay resistance of ash, beech and maple wood modified with N-methylol melamine and a metal complex dye
No full textThis study evaluated the decay resistance of ash (Fraxinus excelsior L), beech (Fagus sylvatica L), and maple (Acer platanoides L) wood impregnated by a full cell process with N-methylol melamine (NMM) and combined NMM-metal complex dye (NMM-BS) in aqueous solutions. Basidiomycete decay testing involved incubation with Coniophora puteana (brown rot) and Trametes versicolor (white rot) according to a modified EN 113 (1996) standard, while for the soft rot fungal resistance was evaluated following the standard ENv 807 (2001). NMM and NMM-BS modifications at a WPG range of 7-11% provided decay protection against brown rot resulting in a mass loss less than the required limit (3%). The NMM and NMM-BS modified wood showed increased resistance to white rot decay; however, a higher WPG is needed to prohibit attack from this hardwood specific fungus. The metal-complex dye alone revealed biocidal effects against basidiomycetes. An increased WPG in NMM or NMM-BS had a positive impact against soft rot decay and the lowest mass losses after 32 weeks of exposure were obtained with NMM modification at about 18-21% WPG. NMM modification at this WPG range, however, was not sufficient to protect the wood from soft rot decay. The wood of beech and maple showed slightly higher resistance to all decay types than ash, probably due to the poorer degree of modification of the latter. (C) 2014 Elsevier Ltd. All rights reserved.AIF through the ZIM cooperation program [KF 2454601GZ9
Strength changes in ash, beech and maple wood modified with a n-methylol melamine compound and a metal-complex dye
No full textAsh, beech and maple wood was modified with aqueous solutions of methylated N-methylol melamine (NMM) and a metal-complex dye (BS) consisting of 10, 20, and 30 % NMM and 5 % BS. Static bending strength and stiffness, impact bending strength and hardness were examined to evaluate the suitability of modified wood for structural uses. The combined NMM-BS modification resulted in significant higher dynamic (MOEdyn) and static (MOE) moduli of elasticity for all species. Beech and maple exhibited enhanced static bending strength (MOR), while that of ash was unchanged. The higher stiffness and strength of NMM-BS modified wood is attributed to its higher wood density and lower EMC and to the stiff character of NMM resin incorporated in the wood matrix. Impact bending strength decreased substantially after modification as a result of reduced pliability of treated wood. Brinell hardness significantly increased with the weight percent gain (WPG) due to modification, and, unlike the other properties, it was positively correlated with the WPG.AIF through the ZIM cooperation program [KF 2454601GZ9
Strength changes in ash, beech and maple wood modified with a n-methylol melamine compound and a metal-complex dye
No full textAsh, beech and maple wood was modified with aqueous solutions of methylated N-methylol melamine (NMM) and a metal-complex dye (BS) consisting of 10, 20, and 30 % NMM and 5 % BS. Static bending strength and stiffness, impact bending strength and hardness were examined to evaluate the suitability of modified wood for structural uses. The combined NMM-BS modification resulted in significant higher dynamic (MOEdyn) and static (MOE) moduli of elasticity for all species. Beech and maple exhibited enhanced static bending strength (MOR), while that of ash was unchanged. The higher stiffness and strength of NMM-BS modified wood is attributed to its higher wood density and lower EMC and to the stiff character of NMM resin incorporated in the wood matrix. Impact bending strength decreased substantially after modification as a result of reduced pliability of treated wood. Brinell hardness significantly increased with the weight percent gain (WPG) due to modification, and, unlike the other properties, it was positively correlated with the WPG.AIF through the ZIM cooperation program [KF 2454601GZ9
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