The research of characteristics of electric arc on weld pool formation

Stability and controllability of a welding arc have a large influence on both the weld quality and welding productivity in the process of welding. Metal fusing and weld forming depend on the forces affecting the arc. Welding current creates electromagnetic forces, which basically define the influence of arc forces on molten metal. While estimating the magnitude of the influence of electromagnetic forces, it is necessary to investigate the radial distribution of arc pressure on the surface of a weld pool and take into account the dependence of distribution of electromagnetic forces on the non-consumable electrode tip geometry

The research of characteristics of electric arc on weld pool formation

Stability and controllability of a welding arc have a large influence on both the weld quality and welding productivity in the process of welding. Metal fusing and weld forming depend on the forces affecting the arc. Welding current creates electromagnetic forces, which basically define the influence of arc forces on molten metal. While estimating the magnitude of the influence of electromagnetic forces, it is necessary to investigate the radial distribution of arc pressure on the surface of a weld pool and take into account the dependence of distribution of electromagnetic forces on the non-consumable electrode tip geometry

Learning Needle Pick-And-Place without expert demonstrations

We introduce a novel approach for learning a complex multi-stage needle pick-and-place manipulation task for surgical applications using Reinforcement Learning without expert demonstrations or explicit curriculum. The proposed method is based on a recursive decomposition of the original task into a sequence of sub-tasks with increasing complexity and utilizes an actor-critic algorithm with deterministic policy output. In this work, exploratory bottlenecks have been used by a human expert as convenient boundary points for partitioning complex tasks into simpler subunits. Our method has successfully learnt a policy for the needle pick-and-place task, whereas the state-of-the-art TD3+HER method is unable to achieve success without the help of expert demonstrations. Comparison results show that our method achieves the highest performance with a 91% average success rate

Constructing a Human Atrial Fibre Atlas

Atrial anisotropy affects electrical propagation patterns, anchor locations of atrial reentrant drivers, and atrial mechanics. However, patient-specific atrial fibre fields and anisotropy measurements are not currently available, and consequently assigning fibre fields to atrial models is challenging. We aimed to construct an atrial fibre atlas from a high-resolution DTMRI dataset that optimally reproduces electrophysiology simulation predictions corresponding to patient-specific fibre fields, and to develop a methodology for automatically assigning fibres to patient-specific anatomies. We extended an atrial coordinate system to map the pulmonary veins, vena cava and appendages to standardised positions in the coordinate system corresponding to the average location across the anatomies. We then expressed each fibre field in this atrial coordinate system and calculated an average fibre field. To assess the effects of fibre field on patient-specific modelling predictions, we calculated paced activation time maps and electrical driver locations during AF. In total, 756 activation time maps were calculated (7 anatomies with 9 fibre maps and 2 pacing locations, for the endocardial, epicardial and bilayer surface models of the LA and RA). Patient-specific fibre fields had a relatively small effect on average paced activation maps (range of mean local activation time difference for LA fields: 2.67-3.60 ms, and for RA fields: 2.29-3.44 ms), but had a larger effect on maximum LAT differences (range for LA 12.7-16.6%; range for RA 11.9-15.0%). A total of 126 phase singularity density maps were calculated (7 anatomies with 9 fibre maps for the LA and RA bilayer models). The fibre field corresponding to anatomy 1 had the highest median PS density map correlation coefficient for LA bilayer simulations (0.44 compared to the other correlations, ranging from 0.14 to 0.39), while the average fibre field had the highest correlation for the RA bilayer simulations (0.61 compared to the other correlations, ranging from 0.37 to 0.56). For sinus rhythm simulations, average activation time is robust to fibre field direction; however, maximum differences can still be significant. Patient specific fibres are more important for arrhythmia simulations, particularly in the left atrium. We propose using the fibre field corresponding to DTMRI dataset 1 for LA simulations, and the average fibre field for RA simulations as these optimally predicted arrhythmia properties

The effect of seaweed fertilizer on summer rapeseed

Laboratoriniuose tyrimuose koncentruoti trąšos su jūros dumbliais tirpalai turėjo įtakos vasarinių rapsų dygimui, šaknų ir kaleoptilių vystymuisi. Geriausias rezultatas gautas vasarinius rapsus apipurškiant 0,1 proc. vnt. koncentracijos trąšų su jūros dumbliais tirpalu. Šiame variante vasariniai rapsai tolygiausiai sudygo, šaknelių ir kaleoptilių ilgiai buvo vienodžiausi, išsivystė stipri šaknų sistema, kuri leidžia tikėtis gero derlingumo ir atsparesnių augalų blogoms meteorologinėms sąlygoms. Lauko eksperimente trąšos su jūros dumbliais turėjo įtakos vasarinių rapsų derlingumui ir cheminei sudėčiai. Naudojant trąšas su jūros dumbliais vasarinių rapsų derlingumas esmingai padidėjo nuo 0,37 iki 0,42 t ha-1 ir atitinkamai siekė 2,89 ir 2,94 t ha-1. Trąšos su jūros dumbliais taip pat turėjo įtakos vasarinių rapsų riebalų kiekiui. Riebalų kiekio esminis padidėjimas 1,10 proc. vnt. pastebėtas vasarinius rapsus tręšiant Eurofertil plius NP 37 Physio trąšomis prieš sėją, stiebo augimo pradžioje Sulfammo 30 ir butanizacijos tarpsnyje Fertileader Gold trąšomis. Trąšos su jūros dumbliais baltymų ir gliukozinolatų kiekiams esminės įtakos neturėjo.The laboratory studies of the concentrated fertilizer with seaweed liquid had an impact on oilseed of summer rapeseed germination, root and the development of coleoptiles. The best result was reached by sputtering 0.1 percents units concentration of fertilizer with seaweed on the summer rapeseed. For this fertilizing version the summer rapeseed most germinated, and root and coleoptiles lengths had been the same and it had developed the strong root system, which allowed expecting a good yield and planting more resistant to bad weather conditions. The experiment on field of fertilizer with seaweed had affected the productivity and chemical composition of summer rapeseed. Using the fertilizer with seaweed the productivity of summer rapeseed was substantially increased from 0.37 to 0.42 t ha-1, respectively reached 2.89 and 2.94 t ha-1. The fertilizers with seaweed had also influenced the fat content of summer rapeseed. It was observed the substantial increase of 1.10 percents for unit on the summer rapeseed fertilized with Eurofertil plius NP 37 Physio before sowing, at stage of stem growth time fertilized with Sulfammo 30, at bud formation time with Fertileader Gold. The fertilizers with seaweed hadn’t significant influence to protein and glucosinolate contents.Žemės ūkio akademijaVytauto Didžiojo universiteta

Bringing politics closer to the people: responsiveness of public election comitees in lithuanian local government

Bringing Politics Closer to the People: Responsiveness of Public Election Comitees in Lithuanian Local Government Nowadays representative democracy faces many challenges and it is easy to notice these challenges in such a young democratic country as Lithuania. Hanna Pitkin noted that one of the main factors that determines quality of democracy is responsiveness so this research tried to find out how responsiveness works, specifically, in Lithuanian local government after electoral reforms were introduced in 2015. Aim of these reforms was to bring politics closer to the people so an assumption was made that recently elected public election comitees are characterized by the biggest and the most various responsiveness in Lithuanian politics. Goal of this work was to understand what kind of responsiveness reveals itself in representation perceptions of these newly elected city council members and why, how and when it functions. To achieve this goal qualitative research method was adopted: 19 semi structured interviews were organized in Kaunas and Alytus – cities in whose councils public election comitees formed the biggest ruling majorities. Members of these coalitions were asked to share their political experience of representing interests of citizens. Questionnaire was constructed under H. Eulau and P. Karps study „Puzzle of Representation“, also, other scholar works in the field of political representation. Theoretical basis and research data allowed to classify perceptible responsiveness into different types while showing each one‘s features. The most common types of responsiveness observed in the concepts of representation formed by Lithuanian local politicians were service responsiveness, pragmatic responsiveness and selective a posteriori responsiveness. Cases of nonresponsiveness were spotted either. After classification was made, causes of current trends also were disclosed. One of the most interesting findings – repeated responsiveness concepts among those city council members who call themselves competent professionals in their field of work. These people came to politics to solve the problems they faced while working so they are either characterized by selective a posteriori responsiveness in their work related area or nonresponsiveness because some of them feel that ordinary people do not comprehend their field, also, they admit that they do not comprehend other fields themselves so they do not interfere with the issues in that other fields. Research findings have opened deeper insights about results of Lithuanian electoral reforms that were implemented in order to make local politics in the country more responsive by allowing non-party candidates to be elected. These non-party members of public election comitees believe that openness helps them to be much more responsive than party members, also, mayors believe that they are more responsive than previous mayors because now they are accountable not only to council members but also to citizens. On the other hand, it was also revealed that changes were not so effective like politicians expected themselves. While analyzing democratic representation problems such as political distrust and passivity, investigating council members perpective might seem not so purposeful after learning that many of them do not consider themselves as politicians because they do not see any politics in a farm compared municipality. However, while discussing possibilities of bringing politics closer to the people, it seems important to investigate political institution which is really close to everyone – local government. This research showed how representatives at this level perceive the concept of representation and how does this concept become the satisfaction of citizens interests in real life

The welding deformations of chrome-nickel stainless steels

Stainless steels are widely used for manufacturing important constructions. Because of their properties, welding deformations of stainless steels are larger than those of mild steels. Therefore it is important to foresee forthcoming welding deformations and their extent. Welding deformations are often calculated using analytical approaches or finite element analysis. In this article the methodologies of Okerblom, Walter, Horst Pflug, Sparagen – Ettinger, Blodgett and finite element analysis, were applied to calculate deformations. The experimental study of deformations was made using austenitic stainless steel X8CrNiTi 18-10. The results of analytic analysis were compared with the results of the experimental analysis

Opera productions of Jean-Pierre Ponnelle, the American years, 1958--1987

grantor: University of TorontoJean-Pierre Ponnelle (1932-1988) has been internationally acclaimed as one of the leading opera directors/designers of this century. He was a multi-faceted artist who fused a high degree of musical knowledge with a boundless theatrical imagination. The force of his conceptual designs for ballets and spoken plays eventually led him to adopt the role of director for operas on stage and film. As a director he worked with the leading conductors and singer-actors of his day in almost every major opera house in the world. The range of his successes covered an enormous range of operas representing every period, genre and style from Monteverdi and Rossini to Wagner and Strauss. Ponnelle was instrumental in reinstating the seria operas of Mozart into the active repertoire and was a formidable champion for new works such as Reimann's 'Lear ' and 'Troades.' The scope of this study encompasses operas that Ponnelle staged in the United States, but also includes many references to his productions in Europe and to his opera films. Since the works examined do not represent the totality of the director's accomplishments, this study does not purport to be exhaustive. However, in choosing the productions the writer considered those that were most representative of his style and which had the greatest critical and popular impact. The principal argument of this dissertation is that Ponnelle's productions were noteworthy for the intrinsic role which music played in their conception and realization. The first chapter acquaints the reader with the multi-faceted artist and his repertoire. The second introduces the main points of his musical methodology and includes a discussion of his ideas against his practice. The remaining chapters analyze representative stage productions and films, with an emphasis on how he utilized music in both design and staging.Ph.D

The effect of seaweed fertilizer on summer rapeseed

The purposes of this job to assessment the fertilizer rates and count forms effectiveness of seaweed fertilizer on summer rapeseed. It was made precision field trials at limnoglacial loam on carbonaceous till, deeper in clay loam, Aleksandro Stulginskio University in 2011 to assess the impact of seaweed fertilizers on yield of summer rapeseed. The ber. yielding (2.94 t ha"1) produced of summer rapeseed fertilized with Eurofertil 37 Physio at stage of main fertilizer time, at stage of sprouting fertilized with ammonium nitrate, at stage of 4-6 leaf fertilized with Fertiactyl Starter and at stage of stem growth time fertilized with Sulfamo 30. On purpose to reach for more fat content of seeds the summer rapeseec is better to fertilize with Fertileader Gold at stage of bud formation than to fertilize with Fertiactyl Starter at stage of 4- 6 leaf. The protein content of summer rapeseeds seeds to different fertilizers growths slightly. The used forms effectiveness on glucosinolate content of seeds has not been establishedVytauto Didžiojo universitetasŽemės ūkio akademij