Methods, algorithms and computer codes for calculation of electron-impact excitation parameters

We describe the computer codes, developed at Vilnius University, for the calculation of electron-impact excitation cross sections, collision strengths, and excitation rates in the plane-wave Born approximation. These codes utilize the multireference atomic wavefunctions which are also adopted to calculate radiative transition parameters of complex many-electron ions. This leads to consistent data sets suitable in plasma modelling codes. Two versions of electron scattering codes are considered in the present work, both of them employing configuration interaction method for inclusion of correlation effects and Breit-Pauli approximation to account for relativistic effects. These versions differ only by one-electron radial orbitals, where the first one employs the non-relativistic numerical radial orbitals, while another version uses the quasirelativistic radial orbitals. The accuracy of produced results is assessed by comparing radiative transition and electron-impact excitation data for neutral hydrogen, helium and lithium atoms as well as highly-charged tungsten ions with theoretical and experimental data available from other sources.Comment: Lithuan. J. Physic

Some friction knots improvements in agricultural machinery

This article contains the material on the research of polyamide slide bearings aiming to use them wider in agricultural machinery. The brief analysis of polymeric materials is provided in order to find out which of them is more suitable for the production of sliding bearings. The laboratory injection molding machine of the polyamide slide bearings was designed and manufactured by pressure to carry out the research, also a stand for slide bearings laboratory testing and other equipment were produced. They are not included in this article. After some bearings’ laboratory tests, they were tested under operating conditions. Detailed tests were carried out determining the smallest space in the slip knot between the inner bearing diameter and the shaft. The observed phenomenon that after inserting the bushing into its housing, within a period of 72 hours, the inner diameter decreases and stabilizes was taken into account. The long-term bearings research was carried out in aggressive environments (dust, water, oil). As a result, conclusions can be drawn about the wider usage of them in agricultural machiney. The long-term bearings research in grass harvesting machinery was carried out (duration – 6 months) in order to investigate the appropriateness of the choice of materials for the production of bearings, as well as the lubrication regime and their operational reliability. While performing operating tests after treating the material, recommendations for a wider use of polymeric bearings, which are presented at the end of the article, were prepared

IV klasės mokinių interesų ir polinkių naudingam darbui psichologinė analizė

The article analyses children’s interests and aptitudes for different types of useful work that have formed in the occupational education family and under the effect of primary grades of secondary school. Having used a method of individual discussion with the 4th grade urban (100 students) and rural (50 students) school students, the author of the article presents materials describing an initial psychological preparedness of children at our republic and discloses in part some psychological peculiarities for the formation of occupational interests and aptitudes. When analyzing the prevailing interests, two types of students were identified: 1) children with expressed interests for different types of mental work, and 2) children with interests for different types of physical work. The majority of children surveyed were attributed to the first type. Conversations showed that only 28% of 4th grade students systemically perform job assignments within their families (except for learning tasks) or perform them accidently at the order of adults. It is characteristic that children who are not taught useful work within their family are also characterized for poorer academic progress at school. 4th grade students insufficiently perceive and appreciate the significance of adult work. Two-thirds of the children surveyed indicated that adults work only for their personal interest in the satisfaction of family needs. Insufficiently developed children’s interests and aptitudes for physical work, specific blue-color occupations, show specific shortcomings of occupational education in the family and at school. Together with the identified psychological peculiarities, the author also provides specific pedagogical recommendations for parents and primary grade teachers seeking to improve psychological preparedness for work of the future communism builders.Straipsnyje analizuojami vaikų interesai ir polinkiai įvairioms naudingo darbo rūšims, susiformavę darbinio ugdymo šeimoje ir vidurinės mokyklos pradinėse klasėse įtakoje. Naudojęs individualių pokalbių metodiką su 4-os klasės miesto (100 mokinių) ir kaimo (50 mokinių) mokyklų mokiniais, straipsnio autorius pateikia medžiagą, apibūdinančią mūsų respublikos vaikų pradinį psichologinį pasirengimą darbui, ir, iš dalies, atskleidžia kai kuriuos darbinių interesų ir polinkių formavimo psichologinius ypatumus. Nagrinėjant vyraujančius interesus, aptikti du mokinių tipai: 1) vaikai su aiškiai išreikštais interesais įvairioms protinio darbo rūšims ir 2) vaikai su interesais įvairioms fizinio darbo rūšims. Pirmam tipui priskirtina didžioji tirtų vaikų dalis. Pokalbiai parodė, kad tik 28% ketvirtokų sistemingai atlieka darbinius pavedimus šeimoje. Likusi dalis arba iš viso neturi jokių darbinių įpareigojimų (išskyrus mokymosi užduotis), arba atlieka atsitiktinai liepus suaugusiems. Būdinga, kad vaikai, nemokomi šeimoje naudingo darbo, pasižymi ir žemesniu pažangumu mokykloje. Ketvirtų klasių mokiniai nepakankamai supranta ir vertina suaugusiųjų darbo reikšmę. 67% vaikų, dalyvavusių pokalbiuose, nurodydavo, kad suaugę dirba tik dėl savo asmeninių interesų, tenkinant šeimos poreikius. Nepakankamai išvystyti vaikų interesai ir polinkiai fiziniam darbui, konkrečioms darbinėms profesijoms rodo konkrečius darbinio ugdymo trūkumus šeimoje ir mokykloje. Kartu su nustatytais psichologiniais ypatumais autorius pateikia ir konkrečias pedagogines rekomendacijas tėvams ir pradinių klasių mokytojams, siekiant pagerinti psichologinį būsimų komunizmo statytojų pasirengimą darbui

Some friction knots improvements in agricultural machinery

This article contains the material on the research of polyamide slide bearings aiming to use them wider in agricultural machinery. The brief analysis of polymeric materials is provided in order to find out which of them is more suitable for the production of sliding bearings. The laboratory injection molding machine of the polyamide slide bearings was designed and manufactured by pressure to carry out the research, also a stand for slide bearings laboratory testing and other equipment were produced. They are not included in this article. After some bearings’ laboratory tests, they were tested under operating conditions. Detailed tests were carried out determining the smallest space in the slip knot between the inner bearing diameter and the shaft. The observed phenomenon that after inserting the bushing into its housing, within a period of 72 hours, the inner diameter decreases and stabilizes was taken into account. The long-term bearings research was carried out in aggressive environments (dust, water, oil). As a result, conclusions can be drawn about the wider usage of them in agricultural machiney. The long-term bearings research in grass harvesting machinery was carried out (duration – 6 months) in order to investigate the appropriateness of the choice of materials for the production of bearings, as well as the lubrication regime and their operational reliability. While performing operating tests after treating the material, recommendations for a wider use of polymeric bearings, which are presented at the end of the article, were prepared

Refractory Materials for Biofuel Boilers

The energy equipment usable for solid biofuel incineration usually operates upon aggressive conditions. The internal structures (lining) of the equipment are made of refractory materials that are affected by combined loads: thermal, mechanical and chemical (i.e. high temperature–up to 1200°C, chemical impact of alkaline compounds and slag, repeating thermal shocks, abrasive effect caused by solid particles and so on). A majority of traditional refractories usable for lining in such equipment are not durable. Upon certain conditions of use (such as high local temperatures, influence of alkaline biofuel combustion products and so on), durability of the traditional materials is 1–2 years only. The opportunities of new refractory materials application should be set upon taking into account the conditions of operation for biofuel boilers of specific types. In this section - the data on the peculiarities of using refractory materials in biofuel boilers are reviewed, and the impact of aggressive operating conditions of such thermal equipment on the properties of refractory materials is discussed. In addition, the investigations results of refractory castables alkali resistance and its explosive spalling are discussed. The recommendations for use of refractory materials in biofuel boilers are also presented

Analysis of exhaust gas composition of internal combustion engines using liquefied petroleum gas

The problems of implementation of liquefied petroleum gas (LPG) supply systems are related with the fact that they are alternative systems used in engines constructed and optimized for work with other kinds of fuel. So assemblers of the systems have to evaluate power losses and at the same time ecological requirements. The experiment is devoted to the analysis of gas composition of engines working at different modes in order to specify the particularity of LPG system tuning and to obtain data for the evaluation of environmental pollution by numerical car dynamics models. It is estimated that the algorithms of current LPG systems balance between ecological requirements and optimization of external characteristics of engines, and the gas systems are characterized by a great inertia. Also, it is determined that more precise tuning algorithms must be constructed, and more tuning points and tuning, when an engine works in standard modes, must be foreseen. Vidaus degimo variklio, varomo suskystintosiomis dujomis, išmetamųjų dujų sudėties tyrimas Santrauka Naudojant suskystintųjų dujų sistemas automobiliuose, pritaikytuose veikti benzinu, susiduriama su įvairiomis, aplinkos taršos problemomis. Todėl sistemų montuotojai turi įvertinti ne tik galios nuostolius, bet ir kaip tos sistemos atitinka ekologinius reikalavimus. Eksperimentuojant siekta ištirti variklio, veikiančio įvairiais režimais, išmetamųjų dujų sudėtį, nustatyti tokios sistemos derinimo ypatumus ir gauti ekologinės taršos vertinimo duomenis analizuojant automobilio skaitmeninius dinaminius modelius. Nustatyta, kad būtina sudaryti tikslesnius suskystintųjų dujų sistemų reguliavimo algoritmus, numatyti daugiau derinimo taškų ir derinti variklį apkrovus, jam veikiant tipiniais režimais. Firstd Published Online: 14 Oct 2010 Reikšminiai žodžiai: išorinė vidaus degimo variklio charakteristika, suskystintosios dujos, aplinkos tarša, išmetamosios dujos

Investigation of influence of nano-reinforcement on the mechanical properties of composite materials

The present work studies the possibility to decrease the formation of micro and nano cracks around short fibres in fibre-reinforced concrete (FRC) composite with the help of nano-reinforcement, which is carbon nanotubes, or micro reinforcement, which is carbon short fibres and nano-fillers. Tensile and bending strength of FRC depends on the spatial distribution of fibres inside a material, type of fibre and cement matrix, as well as an effective micromechanical work of each fibre while pulling out of the concrete matrix. Shrinkage stresses, acting in the matrix in the vicinity of a fibre, lead to the formation of micro-cracks. Such micro-cracks were observed experimentally and were investigated numerically performing broad modelling based on the finite element method (FEM). The investigation was focused on the micromechanical behaviour of a single steel fibre in a cement matrix. Numerical modelling results demonstrated a high level of shrinkage overstresses around steel fibres in concrete. The role of nano and micro admixtures, nanotubes, short carbon fibres as well as the role of water/cement ratio in a high performance concrete matrix, changing (increasing or decreasing) the friction force between the matrix and the steel fibre, were investigated experimentally by way of per­forming a single fibre pull-out tests. The high scatters of experimental results were obtained in performed pull-out tests. At the same time, for the same series of samples, a positive role of micro and nano admixtures and carbon nanotubes in the increase of pull-out force was recognised

Geopolymers based on spent catalyst residue from a fluid catalytic cracking (FCC) process

This paper assesses the use of alkali activation technology in the valorization of a spent fluid catalytic cracking (FCC) catalyst, which is a residue derived from the oil-cracking process, to produce geopolymer binders. In particular, the effects of activation conditions on the structural characteristics of the spent catalyst- based geopolymers are determined. The zeolitic phases present in the spent catalyst are the main phases participating in the geopolymerization reaction, which is driven by the conversion of the zeolitic material to a highly Al-substituted aluminosilicate binder gel. Higher alkali content and SiO2/Na2O ratio lead to a denser structure with a higher degree of geopolymer gel formation and increased degree of crosslinking, as identified through 29Si MAS NMR. These results highlight the feasibility of using spent FCC catalyst as a precursor for geopolymer production.This study was sponsored by research scholarship BES-2008-002440 and EEBB-2011-43847 from the Ministerio de Ciencia y Tecnologia of Spain, the European regional development fund (FEDER), and the Universitat Politecnica de Valencia (Spain). The participation of SAB and JLP was funded by the Australian Research Council through the Discovery Projects program, and also including partial funding through the Particulate Fluids Processing Centre, a Special Research Centre of the ARC. The authors wish to acknowledge the Advanced Microscopy Facility at The University of Melbourne for assistance with the electron microscopy experiments conducted in this study.Rodriguez Martinez, ED.; Bernal, SA.; Provis, JL.; Gehman, JD.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Borrachero Rosado, MV. (2013). Geopolymers based on spent catalyst residue from a fluid catalytic cracking (FCC) process. Fuel. 109:493-502. https://doi.org/10.1016/j.fuel.2013.02.053S49350210

Image of Juzef Pilsudski in the lithuanian press 1926 y. - 1935 y.

Lenkijos maršalas Juzefas Pilsudskis – viena prieštaringiausių asmenybių, kilusių iš Lietuvos. Žemaitiško užsispyrimo ir atkaklumo, plačių savo laiku kairiųjų pažiūrų, nuoširdžiai Tėvynę mylinti ir jos klestėjimo siekianti, kartais dėl savo romantizmu persmelktų užmojų kitų nesuprasta asmenybė. Taip Juzefą Pilsudskį mes galime apibudinti šiandien. Bet 1926 – 1935 metais lietuvių periodika apie jį rašė kitaip. Kodėl ir kaip Juzefas Pilsudskis apibudinamas 1926 – 1935 metų lietuviškoje spaudoje? Tai aptarti ir yra šio tyrimo tikslas. 1926 metais Lenkijoje susidarė krizinė padėtis: apsigynusi nuo Bolševikinės Rusijos, aneksavusi Vilnių ir Vilniaus kraštą bei dalį rytų slavų žemių, Lenkija turėjo didžiulę kariuomenę, kurios išlaikymas kainavo labai daug. Gyventojai tuo buvo nepatenkinti. Vyriausybės buvo silpnos ir nuolatos performuojamos, grėsė suirutė. Kaimyninėse šalyse formavosi diktatūros. Tokiu sudėtingu laikotarpiu įvykius savo naudai sugebėjo nukreipti tuo metu labai kaimynų lietuvių nemėgiamas Juzefas Pilsudskis. Visa tai tiesiogiai atsispindi lietuvių spaudoje. Dienraščiai „Lietuvos žinios“, „Lietuva“, „Lietuvos aidas“, „Lietuvos keleivis“ objektyviai aprašo, kaip Juzefas Pilsudskis atėjo į valdžią, kaip ją sustiprino ir kokių pertvarkymų ėmėsi. Savaitraščiai „Trimitas“, Šaltinis“, „Mūsų rytojus“ kritikuoja Vilniaus krašto užgrobimą, tuo pačiu švelniai puoselėdami Lietuvos gyventojų viltis, pasitaikius palankiai progai, aneksuotas teritorijas susigrąžinti. Aštriausiai kritika dėstoma leidiniuose „Lietuva“ ir „Trimitas“. Visi šie leidiniai Juzefą Pilsudskį vaizduoja kaip griežtą ir stiprios rankos politiką vykdantį kaimyninės valstybės vadovą. Tačiau jam susirgus ir mirus, lietuvių spauda išsamiai aprašo pasiruošimą Lenkijos lyderio laidotuvėms, tuo pačiu aptardama jo nuveiktus darbus. Šia proga publikuojami netgi žymiausio to laiko Lietuvos teisininko Mykolo Riomerio Juzefą Pilsudskį, kaip išskirtinę asmenybę, vertinantys straipsniai. Tokių straipsnių daugiau mes randame tik mūsų laikais, kai, minint įvairias Juzefo Pilsudskio sukaktis, imamasi vertinti jo veiklą iš laiko perspektyvos. Taigi, mūsų laikais Juzefas Pilsudskis vertinamas ne tik kaip autoritariškas Lenkijos vadovas, bet ir kaip charizmos kupina asmenybė.Polish marshal Juzef Pilsudski is one of the most controversial individuals originating from Lithuania. He was stubborn and persistent as a true Samogitian. He was also open-mindedly left-wing politician. He loved his homeland and seeked that it would thrive. Because of these qualities, he was sometimes misunderstood. All these qualities mentioned above were attributed to him only recently. In 1926 - 1935 he was viewed very differently. My thesis is aimed at analysing how Juzef Pilsudski was seen at that time and why he was perceived that way. Poland in 1926 was going through a crisis: after defending itself from Bolshevik Russia, Poland annexed Vilnius and the region around it and some parts of slavic lands. Poland was able to achieve it using its extensive military, which cost a fortune to maintain. People were not happy about it. The government was unstable and often reformed. This could easily lead to upheaval. Neighbouring countries had dictatorships taking over their governments. In this difficult time Juzef Pilsudski managed to use the situation for his benefit. For that he was not favored by lithuanians. That can be clearly seen in the press from that time. Daily papers such as “Lietuvos zinios”, “Lietuva”, “Lietuvos aidas”, “Lietuvos keleivis” objectively portray how Juzef Pilsudski took over the government and reformed it. Weekly papers “Trimitas”, “Saltinis'', “Musu rytojus” criticize annexation of the region of Vilnius, while at the same time keeping up hopes of lithaunian people that once the opportunity presents itself, these lands will be returned to Lithuania. The harshest critics of Pilsudski were “Lietuva” and “Trimitas”. All these papers portrayed him as a stern and tough ruler. However, after his death, papers in Lithuania covered all the proceedings of his funeral and his life work in depth. Famous lithuanian lawyer, Mykolas Riomeris, even published articles, where he calls Juzef Pilsudski an extraordinary person. Similar articles praising Pilsudski can only be found in modern days which are dedicated to honour various anniversaries. In these articles, Juzef Pilsudski and his work is analysed from the perspective of time. Therefore, he is described not only as an authoritarian leader of Poland but also as a very charismatic personality.Istorijos katedraHumanitarinių mokslų fakulteta

Application of geo-social queries

There is a huge amount of data generated on social networks on daily basis. Data from social networks and GPS data collected from users' mobile devices makes a Geo-Social Network. In this paper Geo-Social queries are implemented to analyze data from Geo-Social network. This data can be used for finding target audiences for advertisements or selecting rescue teams for disaster recovery. A model for executing Geo-Social queries and algorithms for query processing system is presented in this paper. Functions for evaluating geographical and social distances are defined. For evaluation of social distance between users, structural equivalence measure is used in this paper. With the help of Geo-Social queries, location prediction model of next user check-in is created. Quality threshold clustering algorithm is used to create clusters of check-ins. Check-ins are clustered together to find familiar regions for each user in Geo-Social network. Finding familiar regions for each user allows to classify check-ins into performed near familiar areas and performed in new ares. In this paper user's movement among clusters is modeled with Markov Chains model. An implementation of query processing system is presented by using real data from Gowalla social network. Location predictions are performed by different methods. First method uses user's location to predict location of next check-in. In another method location data of user's friends is used to make predictions. Third method combines user's location and his friends location data for prediction making. Finally, user's location and time of check-ins is used to make predictions. These methods are compared showing, that different method allows to achieve different prediction success rate. Finally, algorithms to make location recommendations for users in social networks are presented. Recommendations providing is tested on different types of users. Results described in this paper show, that Geo-Social queries are a useful tool for looking for insights in Geo-Social data. Implementation of Markov chains model in Geo-Social querying gives good results for predicting location of user's next check-in. Also Analysis of data from Gowalla social network show that users are making enough check-ins for using this data in Geo-Social queries. Results of simulations of recommendations making model show that accuracy of recommendations varies when different model parameters values are used