Tallinn University of Technology

About: Tallinn University of Technology is a education organization based out in Tallinn, Estonia. It is known for research contribution in the topics: European union & Computer science. The organization has 3688 authors who have published 10313 publications receiving 145058 citations. The organization is also known as: Tallinn Technical University & Tallinna Tehnikaülikool.

Acetylated microfibrillated cellulose as a toughening agent in poly(lactic acid)

Abstract: Composites from poly(lactic acid) (PLA) and acetylated microfibrillated cellulose (MFC) were prepared by a solvent casting technique. MFC, mechanically isolated from never-dried bleached birch Kraft pulp, was used as a reinforcement. The acetylation reaction was carried out at 105°C in toluene and proved to be an effective way of increasing the dispersion of MFC in a nonpolar solution of PLA in chloroform. The maximum acetyl content (10.3%) was achieved after 30 min of reaction time. This could be translated to a degree of substitution (DS) of 0.43. The acetylation was confirmed by Fourier transform infrared spectroscopy. MFC with a higher DS exhibited a more pronounced effect on the properties of PLA. Mechanical testing showed that Young's modulus increased by approximately 70% and the tensile strength increased by approximately 60% at a fiber weight fraction of 20%. At an MFC loading of 10 wt %, the strain at break and toughness, expressed as the work of fracture, increased by around 500%. The Young's modulus increased by approximately 15%, whereas the tensile strength remained the same. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012

Multi-Attribute Decision-Making Methods for Assessment of Quality in Bridges and Road Construction: State-of-the -Art Surveys

Abstract: Multi-attribute analysis (MAA) is a popular tool in many economical, managerial, and constructional problems. This document provides a review of international and national practices in investment decision support tools in bridges and road quality management. Cost benefit analysis (CBA) and MAA are principal methodologies in supporting decisionmaking in bridges and road quality management. The complexity of the applications shows significant differences in international practices. There are ongoing discussions among practitioners and researchers, regarding which one is more appropriate in supporting decisionmaking. It is suggested that more than one approach should be regarded as complementary instead of competitive means. MAA may be particularly helpful in early stages of project development and strategic planning. CBA is used most widely for project prioritization and selecting the final project from a set of alternatives. These methodologies are applicable to the problems with large numbers of scenarios and attributes. The research has concluded that multi-attribute decisionmaking methods are very useful for bridge and road construction.

Copulation in antiarch placoderms and the origin of gnathostome internal fertilization

Abstract: The discovery of claspers in fossils of antiarch placoderms, an ancient group of armoured fish, suggests that internal fertilization was the ancestral type of reproduction for all jawed vertebrates: this contrasts with the current understanding that external fertilization must be the ancestral state. It is usually assumed that internal fertilization by copulation, where it occurs, must have evolved from external fertilization such as free spawning. Many sharks, however, have internal fertilization facilitated by pelvic organs in the males known as claspers. Claspers have also been described in two groups of placoderms, the arthrodires and ptyctodonts, ancient jawed vertebrates known only as fossils, suggesting that internal fertilization in jawed vertebrates may have been the primitive state. Arthrodires and ptyctodonts are derived placoderms however, leaving open the possibility that they evolved claspers independently. This now seems unlikely following the description of claspers in a third and extremely primitive placoderm group, the antiarchs. This creates a new puzzle. Placoderms are often viewed as 'stem' gnathostomes from which all modern jawed vertebrates evolved. So either internal fertilization was primitive for all jawed vertebrates, or placoderms were an evolutionary dead-end in which claspers evolved several times independently. Reproduction in jawed vertebrates (gnathostomes) involves either external or internal fertilization1. It is commonly argued that internal fertilization can evolve from external, but not the reverse. Male copulatory claspers are present in certain placoderms2,3,4, fossil jawed vertebrates retrieved as a paraphyletic segment of the gnathostome stem group in recent studies5,6,7,8. This suggests that internal fertilization could be primitive for gnathostomes, but such a conclusion depends on demonstrating that copulation was not just a specialized feature of certain placoderm subgroups. The reproductive biology of antiarchs, consistently identified as the least crownward placoderms5,6,7,8 and thus of great interest in this context, has until now remained unknown. Here we show that certain antiarchs possessed dermal claspers in the males, while females bore paired dermal plates inferred to have facilitated copulation. These structures are not associated with pelvic fins. The clasper morphology resembles that of ptyctodonts, a more crownward placoderm group7,8, suggesting that all placoderm claspers are homologous and that internal fertilization characterized all placoderms. This implies that external fertilization and spawning, which characterize most extant aquatic gnathostomes, must be derived from internal fertilization, even though this transformation has been thought implausible. Alternatively, the substantial morphological evidence for placoderm paraphyly must be rejected.

Exposure to CuO nanoparticles changes the fatty acid composition of protozoa Tetrahymena thermophila.

Abstract: :Inthecurrentstudy,thetoxicitymechanismofnanosizedCuO(nCuO)tothefreshwaterciliatedprotozoaTetrahymenathermophilawas studied. Changes in fatty acid profile, lipid peroxidation metabolites and reactive oxygen species (ROS) were measured. BulkCuO and CuSO 4 served as controls for size and solubility and 3,5-dichorophenol (3,5-DCP) as a control for a chemical known todirectlyaffectthemembrane composition.Exposure toallcoppercompoundsinducedthegeneration ofROS,whereasnCuOwasmostpotent.Thelattereffectwasnotsolelyexplained bysolubilizedCu-ionsandwas apparentlyparticle-related.24hexposureofprotozoa to 80 mg/L of nCuO (EC50) significantly decreased the proportion of two major unsaturated fatty acids (UFA) (C18:3cis-6,9,12, C18:2 cis-9,12), while it increased the relative amount of two saturated fatty acids (SFA) (C18:0, C16:0). AnalogouseffectwasnotobservedwhenprotozoawereexposedtoequitoxicsuspensionsofbulkCuO,Cu-ionsor3,5-DCP.AschangesintheUFA:SFA upon exposure of protozoa to nCuO were not detected at 2 h exposure and no simultaneous dose- or time-dependentlipidperoxidationoccurred,itislikelythatoneoftheadaptationmechanismsofprotozoatonCuOwasloweringmembranefluiditybytheinhibitionofdenovosynthesisoffattyaciddesaturases.Thisisthefirststudyoftheeffectsofnanoparticlesonthemembranefatty acid composition.’INTRODUCTIONCopperisanessentialtraceelementinlivingorganismswhichplays a vital role in the function of proteins, but can also exerttoxic effects to cells due to its redox activity and affinity for thebinding sites of other metals.

Audiovisual emotion recognition in wild

Abstract: People express emotions through different modalities. Utilization of both verbal and nonverbal communication channels allows to create a system in which the emotional state is expressed more clearly and therefore easier to understand. Expanding the focus to several expression forms can facilitate research on emotion recognition as well as human–machine interaction. This article presents analysis of audiovisual information to recognize human emotions. A cross-corpus evaluation is done using three different databases as the training set (SAVEE, eNTERFACE’05 and RML) and AFEW (database simulating real-world conditions) as a testing set. Emotional speech is represented by commonly known audio and spectral features as well as MFCC coefficients. The SVM algorithm has been used for classification. In case of facial expression, faces in key frames are found using Viola–Jones face recognition algorithm and facial image emotion classification done by CNN (AlexNet). Multimodal emotion recognition is based on decision-level fusion. The performance of emotion recognition algorithm is compared with the validation of human decision makers.