Preparation of homogeneous vitreous materials for electronic and optical devices

Vitreous material builds up as series of solidified layers on inside walls of sealed quartz ampoule containing molten constituents of material, and forms well defined shapes to close dimensional tolerances. Ampoules are made of material which does not react with melt and has lower thermal expansion coefficient than solidified layer

Laser-fired contact optimization in c-Si solar cells

In this work we study the optimization of laser-fired contact (LFC) processing parameters, namely laser power and number of pulses, based on the electrical resistance measurement of an aluminum single LFC point. LFC process has been made through four passivation layers that are typically used in c-Si and mc-Si solar cell fabrication: thermally grown silicon oxide (SiO2), deposited phosphorus-doped amorphous silicon carbide (a-SiCx/H(n)), aluminum oxide (Al2O3) and silicon nitride (SiNx/H) films. Values for the LFC resistance normalized by the laser spot area in the range of 0.65–3 mΩ cm2 have been obtaine

Sample Entropy Computation on Signals with Missing Values

Sample entropy embeds time series into m-dimensional spaces and estimates entropy based on the distances between points in these spaces. However, when samples can be considered as missing or invalid, defining distance in the embedding space becomes problematic. Preprocessing techniques, such as deletion or interpolation, can be employed as a solution, producing time series without missing or invalid values. While deletion ignores missing values, interpolation replaces them using approximations based on neighboring points. This paper proposes a novel approach for the computation of sample entropy when values are considered as missing or invalid. The proposed algorithm accommodates points in the m-dimensional space and handles them there. A theoretical and experimental comparison of the proposed algorithm with deletion and interpolation demonstrates several advantages over these other two approaches. Notably, the deviation of the expected sample entropy value for the proposed methodology consistently proves to be lowest one

The Papyrus Digital Library: Discovering History in the News

Abstract. Digital archives comprise a valuable asset for effective information retrieval. In many cases, however, the special vocabulary of the archive restricts its access only to experts in the domain of the material it contains and, as a result, researchers of other disciplines or the general public cannot take full advantage of the wealth of information it offers. To this end, the Papyrus research project has worked towards a solution which makes cross-discipline search possible in digital libraries. The developed prototype showcases this approach demonstrating how we can discover history in news archives. In this demo we focus on demonstrating two of the end user tools available in the prototype, the cross-discipline search and the Papyrus browser

Analysis Of Active Harmonic Compensation Algorithms For Grid-Connected Photovoltaic Inverters

A review of various standards, concerning distributed generation, and different Active Harmonic Compensation (AHC) or Active Power Filtering (APF) methods are presented in this paper. Short overview of each control method is given. The experimentation results from various publications are taken into account evaluating the feasibility of an AHC algorithm to be integrated in a typical commercially available grid-connected Photovoltaic inverter. The comparison results are presented in a table. The results of this paper can be used for further investigation in deciding which particular algorithm to try to implement and experiment with.</p

A research of buildings demolition and waste recycling technologies

The main aim of this thesis is to analyze possible technologies of buildings deconstruction and demolition for different buildings constructions and to determine recycling and usage possibilities of formed demolition waste. In this thesis was analyzed literature sources in which were reviewed demolition models, alternative methods of demolition technologies and analyzed demolition technologies and their usability. Abandoned and improper explotation of buildings and formed construction waste recycling in Lithuania also was reviewed. In the research part was made a survey of companies engaging with demolition works, determined working price of concrete demolished building, recycling costs of formed waste and waste value as building material. This thesis is made from three chapters, thesis conclusions and references

Analysis of active harmonic compensation algorithms for grid-connected photovoltaic inverters / Aktyvusis harmonikų kompensavimas saulės elektrinių tinklo inverteriais – algoritmų analizė

A review of various standards, concerning distributed generation, and different Active Harmonic Compensation (AHC) or Active Power Filtering (APF) methods are presented in this paper. Short overview of each control method is given. The experimentation results from various publications are taken into account evaluating the feasibility of an AHC algorithm to be integrated in a typical commercially available grid-connected Photovoltaic inverter. The comparison results are presented in a table. The results of this paper can be used for further investigation in deciding which particular algorithm to try to implement and experiment with. Santrauka Pateikta standartų, taikomų paskirstytosioms elektrinėms jungti į žemos įtampos elektros skirstomuosius tinklus, apžvalga. Išnagrinėtas aktyvusis harmonikų kompensavimo (AHK) aspektas, esantis šiuose standartuose. Pateikti harmonikų limitai, kuriuos turi atitikti jungiamos į žemos įtampos elektros tinklą paskirstytosios elektrinės. Apžvelgti skirtingi AHK metodai, pateikta kiekvieno algoritmo analizė. Atsižvelgiant į galimybę AHK įgyvendinti šiuo metu komerciškai gaminamuose saulės elektrinių tinklo inverteriuose (SETI), tarpusavyje palyginti skirtingi AHK pagal algoritmų skaičiavimo intensyvumą, daviklių skaičių, topologiją, maksimaliai kompensuojamų harmonikų skaičių ir priklausomybę nuo apkrovos tipo. Reikšminiai žodžiai: saulės energija, saulės elektrinės tinklo inverteris (SETI), aktyvusis harmonikų kompensavimas.

The Research of Photovoltaic Converters Energy Quality Improvement Methods

Disertacijoje nagrinėjamos fotovoltinių keitiklių tiekiamos elektros energijos kokybės problemos. Disertacijoje sprendžiami fotovoltinių keitiklių pasyviojo harmonikų kompensavimo žemųjų dažnių filtru bei aktyviojo kompensavimo, kai kompensavimui naudojama keitiklio tiekiama fotovoltinė energija, uždaviniai. Darbe pasiūlyta kurti fotovoltinius keitiklius, skirtus ne tik aktyviosios elektros energijos tiekimui, bet ir tinklo energijos kokybės gerinimui, tiekiant ne tik pirmąją, bet ir būtinas tinklo srovės ir įtampos netiesinių iškraipymų kompensavimui aukštesniąsias srovės harmonikas. Disertaciją sudaro įvadas, trys skyriai, rezultatų apibendrinimas, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašai. Įvadiniame skyriuje aptariama tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, formuluojamas darbo tikslas ir uždaviniai, aprašoma tyrimų metodika, darbo mokslinis naujumas, darbo rezultatų praktinė reikšmė, ginamieji teiginiai. Įvado pabaigoje pristatomi pranešimai konferencijose ir disertacijos struktūra. Pirmasis skyrius skirtas literatūros apžvalgai. Jame pateikta fotovoltinių keitiklių ir jų tiekiamos energijos kokybės gerinimo metodų, paremtų pasyviojo ir aktyviojo harmonikų kompensavimo principais, analizė. Skyriaus pabaigoje formuluojamos išvados ir disertacijos uždaviniai. Antrajame skyriuje pateikti fotovoltinio keitiklio pasyviojo harmonikų kompensavimo metodo, naudojant žemųjų dažnių filtrą, eksperimentiniai tyrimai ir tyrimai naudojant modeliavimą. Gautos harmoninių iškraipymų priklausomybės nuo filtro elementų ir formuojamos keitiklio išėjimo įtampos parametrų. Atliktas energijos nuostolių filtre tyrimas, nustatyti būdai jų mažinimui. Trečiajame skyriuje pateikti aktyviojo harmonikų kompensavimo fotovoltinių modulių keitikliu tyrimų rezultatai. Sudaryta keitiklio pagrindinės harmonikos valdymo sistema, kurioje panaudotas rezonansinis valdiklis, atlikti šios sistemos tyrimai. Pasiūlytas ir keitiklyje pritaikytas aukštesniųjų harmonikų detektavimo metodas. Sudarytas fotovoltinio keitiklio su aktyviuoju harmonikų kompensavimu modelis dinaminių procesų modeliavimo programai Simulink, atliktas jo tyrimas modeliuojant. Panaudojant programuojamą inverterį sudarytas fotovoltinio keitiklio su aktyviuoju harmonikų kompensavimu tyrimų stendas ir atlikti keitiklio eksperimentiniai tyrimai. Gauti rezultatai parodė, kad fotovoltinis keitiklis geba atlikti aktyviojo harmonikų kompensavimo funkciją. Disertacijos tema paskelbti 7 straipsniai ir perskaityta 11 pranešimų mokslinėse konferencijose. Disertacijos darbai susieti su 2 mokslinių tyrimų projektais

Geography of political preference during the presidential elections

The electoral geography is one of the richest branches of political geography. The explanation of elections and their results is one of the interests of electoral geography. There were a lot of elections and referendums in Lithuania after 1990 but electoral geography is still developed poorly. There are just some scientific articles about this theme in Lithuania. The elections still remain an object of sociology and political science, though the political (electoral) behaviour (preference) of voters differs in regions strongly. The aim of the article is to determine the social and economical factors, which used to be influence on the political preference of voters during presidential elections since 1997 till 2002, and to establish the regions of the political preference in the period of 1997-2002. The magnitude of A. Paulauskas' electorate was depended on the share of national minorities and countryside voters, unemployment level, V. Adamkus' - the share of Lithuanians, urbanisation and unemployment (negatively) level, V. Landsbergis' - the share of Lithuanians and pensioners, K. Bobelis' - the share of Lithuanians during presidential elections in 1997.The bias of K. Bobelis' electorate was concentrated at Suvalkija region, the voters of other candidates were distributed in Lithuania evenly. In the second tour the electorate of V. Adamkus was concentrated in cities (except Vilnius) and Žemaitija. The share of pensioners was influenced on electorate of A. Paulauskas and V. Šerėnas, national minorities - on electorate of A. Paulauskas and K. Prunskienė, urbanisation - on support of V. Adamkus, the share of countryside voters - on electorate of V. Andriukaitis during presidential elections in 2002. The support of V. Adamkus took new features since 1997 till 2002: the electorate was concentrated in cities and became very weak in northern Žemaitija. There were A. Paulauskas' and K. Prunskienė' voters concentrated in eastern Lithuania. The President R. Paksas won evidently in northern Žemaitija and Šiauliai county, eastern Lithuania and southwest Lithuani