The goal of this work is to extend the state-of-the-art in digital medical X-ray imaging as it pertains to real-time, low-noise imaging and multi-mode imager functionality. One focus of this research in digital flat-panel imagers is to increase the detective quantum efficiency, particularly at low X-ray exposures, in order to enable low-noise imaging applications such as fluoroscopy or tomographic mammography. Another focus of this research is in the creation of a multi-mode imager, such as a combined radiographic and fluoroscopic (R&F) imager, which will reduce hospital costs, both in terms of equipment acquisition and storage space. To that end, we propose a novel three-transistor multi-mode digital flat-panel imager with a dynamic range capable for use in R&F applications, with a particular focus on noise optimization for low-noise real-time digital flat-panel X-ray fluoroscopy. This work involves the derivation and optimization of the total input referred noise of an active pixel sensor (APS) in terms of the on-pixel thin-film transistor device dimensions. It is determined that in order to minimize noise, all non-transistor capacitances at the pixel sense node needed to be minimized. This leads to a design where the on-pixel storage capacitance is eliminated; and instead the gate capacitance of the sense-node transistor is used to store the incoming X-ray converted charge. This work allows researchers to gain insight into the fundamental noise operation of active pixels used in medical imaging, and to appropriately choose device dimensions. Due to the inherent large feature sizes of thin-film transistors, active pixel flat-panel X-ray medical imagers offer lower resolution than their film-screen counterparts. By demonstrating the desirability of smaller device dimensions for reduced noise and the elimination of a storage capacitor, this research frees some of the area constraints that exist in active pixel flat-panel imagers, allowing for smaller pixels, and thus higher resolution medical imagers. The noise analysis and optimization as a function of pixel TFT device dimensions in this work is applicable to any amorphous silicon (a-Si) based charge-sensitive pixel, and is easily extended to other device technologies such as polysilicon (poly-Si). iv In addition, experimental results of a 64x64 pixel four-transistor APS imaging array fabricated in a-Si technology and mated with an a-Se photoconductor for use in medical X-ray imaging is presented. MTF results and transient response in the presence of X-rays (image lag) for the APS array are poor, which is ascribed to high charge trapping at the silicon nitride/a-Se interface. Improvements to the silicon nitride passivation layer and pixel layout are suggested to reduce this charge trapping. The prototype imager is compared directly with a state-of-the-art a-Si PPS imaging array and demonstrates good SNR performance for X-ray exposures down to 1.5μR. Pixel design and fabrication process improvements are suggested for low-exposure APS testing and improved low-noise performance.

Microstructural evolution in a naturally-aged and cold-rolled AA6451 aluminum alloy during a non-isothermal annealing process, which leads to significant grain refinement, is investigated through: (a) conducting a comprehensive experimental analysis and (b) developing a computational modeling technique. The underlying mechanisms of annealing have been investigated through analysing interactive phenomena between precipitation and concurrent recovery and recrystallization. It is shown that the interactions between solute elements, clusters, and fine precipitates with dislocations restrict dynamic and static recovery during deformation and subsequent annealing. Inhibition of recovery favours recrystallization that initiates at 300oC and progresses through a nucleation and growth mechanism. Despite localized inhomogeneities, nucleation mainly occurs in non-recovered high energy sites which are uniformly distributed within the entire structure. Growth of the recrystallized nuclei is restricted by pinning precipitates that undergo a concurrent coarsening process. The fine, uniform distribution of recrystallized nuclei and their limited growth result in the formation of a fine-grained microstructure, after completion of recrystallization. The acquired knowledge has been used to develop a computational modeling technique for simulating microstructural evolution of the alloy. Microstructural states are simulated by integrating analytical approaches in a Monte Carlo algorithm. The effects of deformation-induced and pre-existing inhomogeneities, as well as precipitate coarsening and grain boundary pinning on the competitive recovery-recrystallization process are included in the simulation algorithm. The developed technique is implemented to predict the microstructural evolution during isothermal and non-isothermal annealing of AA6xxx sheets. A good quantitative agreement is found between the model predictions and the results from the experimental investigations.

Ce travail a pour but de comprendre l'effet de la compensation du dopage sur les performances des cellules photovoltaïques à base de silicium de qualité solaire purifié par voie métallurgique. Après avoir développé la physique des matériaux compensés, l'influence de la compensation a été étudiée à l'échelle de la plaquette. Nous avons mis en évidence une forte réduction non prédite de la mobilité des porteurs. Au contraire, la compensation du dopage s'est avérée bénéfique à la durée de vie volumique. Nous avons précisé les propriétés recombinantes des dopants. L'étude a été transposée à l'échelle de la cellule. Des rendements de 16% ont été obtenus sur des cellules fortement dopées et compensées. La présence de nombreuses associations entre impuretés dopantes et défauts nous a conduits à l'élaboration d'un algorithme permettant de simuler la cinétique de ce type d'association. Enfin, deux techniques innovantes de mesure des teneurs en dopants et en oxygène interstitiel ont été présentées.

Adaptyvios virtualios mokymo(si) aplinkos (AVMA) kontekste analizuojama mokymo(si) programa bei jo verifikacijos strategijų pritaikymas. Mokymo(si) programa - terminas, apibūdinantis kiekvieno registruoto vartotojo galimybę modifikuotoje VMA pasirinkti studijuotinas temas, mokymo medžiagos pateikimo pavidalą, pasirinkti pageidaujamą mokymosi lygmenį. Verifikacija – procesas, kuris yra vykdomas modifikuotoje VMA susikurtame mokymosi plane, siekiant nustatyti, ar ką tik sudarytas nustatymų rinkinys atitinka realius besimokančiojo poreikius. Tam patikrinti naudojamos įvairios strategijos, kurios ne visada būna optimalios, o dažnai ir stabdančios mokymosi procesą. Taikant mokslinėje literatūroje apra��ytas strategijas arba ieškant naujų, siekiama surasti tinkamiausią verifikacijos strategiją ir pritaikant ją VMA. / This paper in a condensed form presents a model of the component for a virtual learning environment (VLE), which enriches it with some adaptive features. Such features are curriculum and verification strategies. First one is understood as the set of courses and their content, which learner can choose according his needs. Second one understanding as process, which execute in modifies VLE and check knowledge of learner’s of course material using tests and after it update curriculum that satisfies the needs of the learner. Verification’s strategies used often are not optimal and delays study process. The aim of this work is definition of verification strategy, which is applied for correction of prebuild learner’s curriculum, and implementation of it into VLE.

Specialiųjų poreikių vaikai – tai mūsų visuomenės dalis, todėl būtina gilintis į jų problemų sprendimą, padėti prisitaikyti prie juos supančios aplinkos, pritapti ir surasti savo vietą visuomenėje. Neįgaliųjų vaikų integracija – viena iš aktualiausių diskusijų, mokslinių konferencijų bei mokslinės literatūros temų. Tyrimo tikslas – atskleisti mokinių, besimokančių pagal individualizuotas programas socialinį – edukacinį portretą. Tyrimo uždaviniai: 1. Atlikus mokslinės literatūros analizę, atskleisti mokinių, turinčių specialiųjų poreikių integravimo galimybes. 2. Aptarti mokinių, turinčių specialiųjų poreikių, socialinį – edukacinį portretą instituciniu ( mokyklos ) lygmeniu. 3. Atskleisti mokinių, turinčių specialiųjų poreikių, socialini- edukacinį portretą mokymosi veiklos lygmeniu. 4. Aptarti mokinių, turinčių specialiųjų poreikių, socialinį – edukacinį portretą tarpasmeniniu lygmeniu. Tyrimo metodai: mokslinės literatūros analizė, Q tipo duomenų rinkimas ( anketinė apklausa), lyginamoji analizė, kokybinė ir statistinė duomenų analizė. Anketos parengtos trims respondentų grupėms: 5-9 klasių, specialiųjų poreikių turintiems mokiniams ( 39 mokiniai ), mokytojams ( 23 mokytojai ) ir tėvams ( 27 tėvai) Respondentų nuomone vaikų besimokančių pagal individualizuotas programas, padėtis bendrojo lavinimo mokykloje pasireiškia vienodais lūkesčiais, ugdymo tikslais ir metodais, tai viena iš svarbiausių teigiamos vaiko savijautos mokykloje prielaidų. Tyrimo metu... [toliau žr. visą tekstą] / Special needs children - is our society, it is necessary to look into their problems, to adapt to their environment, to adapt and find their place in society. Integration of Disabled Children - one of the most pressing debates, conferences and literature themes. Purpose of the survey - to reveal students' learning under individualized programs of social - educational portrait. The tasks were: 1. After the literature analysis, detection of students with special needs into opportunities. 2. Discuss pupils with special needs, social - educational portrait of institutional (school) level. 3. Reveal students with special needs, socio-educational profile for learning at the operational level. 4. Discuss pupils with special needs, social - educational portrait interpersonal level. Research methods include literature review, Q-type data collection (questionnaire), a comparative analysis of qualitative and statistical data analysis. Profiles of respondents drawn three groups: 5-9 grade, special needs pupils (39 pupils), teachers (23 teachers) and parents (27 parents) Felt to be individualized according to children's learning programs on secondary school gets the same expectations, educational goals and methods, it is one of the most important positive well-being of the child's school history. The study showed that the individualization of educational programs for students released - a long-term, systematic, planned event. The analysis of pupils with social -... [to full text]

Mokyklinės matematikos mokymo(si) priemonė skirta vyresniųjų klasių moksleiviams, kurioje pateikta matematikos mokyklinio brandos egzamino temų teorija ir uždavinių pavyzdžiai, savikontrolės uždaviniai ir kontroliniai testai. / The mathematics tool for learning is targeted to the students of higher forms and includes the theory of particular topics and task examples, self-monitoring, check tests and assessment tasks.

Magistro darbo santrauka Magistro darbe atlikta teorinė pedagogų pasirengimo ugdyti mokinius, turinčius specialiųjų ugdymo poreikių, analizė. Iškelta hipotezė, kad bendrojo lavinimo mokyklų pedagogai nuvertina savo kompetencijas tenkinti aukštesniųjų klasių mokinių specialiuosius ugdymosi poreikius ir tai didele dalimi lemia nepakankamas pastangas ugdyti šiuos mokinius. Anketinės apklausos metodu buvo atliktas tyrimas, kurio tikslas – ištirti pedagogų poţiūrį į kompetencijas tenkinti aukštesniųjų klasių mokinių poreikius. Atlikta statistinė (aprašomoji daţnių, procentų) duomenų analizė. Tyrime dalyvavo 180 bendrojo lavinimo mokyklų aukštesniųjų klasių pedagogų, ugdančių aukštesniųjų klasių mokinius, turinčius specialiųjų ugdymosi poreikių. Empirinėje dalyje nagrinėjama: pedagogų pasirengimas ugdyti mokinius, turinčius specialiųjų ugdymosi poreikių; pedagogų nuomonės apie mokinių, turinčių specialiųjų ugdymosi poreikių, mokymą; jų suvokiamus šių mokinių ugdymo tikslus ir patiriamas problemas; pedagogų profesinių kompetencijų įsivertinimas; pedagogų profesinės saviugdos poreikiai. Svarbiausios empirinio tyrimo išvados: 1. Mokinius, turinčius specialiųjų poreikių, mokytojai laiko lygiaverčiais mokyklos bendruomenės nariais, o mokinių individualių ugdymosi poreikių tenkinimą – svarbiausiu jų mokymo bruoţu. Tačiau mokymo(si) pasiekimai, mokytojų nuomone, labiausiai priklauso nuo šeimos ir paties vaiko. 2. Dauguma pedagogų, ugdydami specialiųjų poreikių mokinius, siekia formuoti... [toliau žr. visą tekstą] / Summary The paper deals with the theoretical analysis of the teachers’ preparedness to educate the pupils with special educational needs. It was brought up the hypothesis that general education school teachers devalue their competences to satisfy the special educational needs for the senior pupils and that is the basic influence to bear on incomplete efforts to educate these pupils. The research was fulfilled using the results of the inquest. It’s goal – to survey teachers’ attitude towards the competence to meet the requirements for senior pupils with special educational needs. The analysis of the statistic (descriptive rate, percentage) data was done. 180 general education school teachers, working with the senior pupils with special educational needs, participated in this research. In empirical part are analyzed: teachers’ preparedness to work with the pupils with special educational needs; teachers’ opinion about the education of the pupils with special educational needs; their comprehensible educational goals and accident – prone problems teaching these pupils; the self – evaluation of teachers pedagogical professional competences; teachers’ professional self – education needs. The most important empirical conclusions that were drawn are: 1. Teachers consider the pupils with special educational needs as the equal members of school community; the satisfaction of pupils’ individual educational needs is hold as the main feature of their teaching. But the achievements of... [to full text]

Al-Si based alloys are commonly used in the automobile industry due to their superior properties, high strength to weight ratio, corrosion resistance, recyclability, etc. These alloys are fabricated by casting and powder metallurgy techniques in which porosity is a common feature. The presence of pores is accompanied by a decrease in mechanical properties, i.e., a drop in hardness and ductility of the materials. In the present study, an attempt was made to understand the effect of surface porosity on the tribological property. A380M and Al-6wt% Si alloys were used to prepare specimens containing 2.6 to 6.9% porosity via casting and 1 to 6.7% porosity via powder metallurgy techniques, respectively. Dry sliding wear behavior was investigated in the load range 6-20 N against an AISI 52100 bearing steel ball using a reciprocating ball-on-flat configuration at a frequency range of 4-20 Hz for cast and 15 Hz for P/M samples.

Visais laikais aritmetika buvo svarbus mokomasis dalykas mokykloje: mokiniai susipažįsta su natūraliaisiais ir trupmeniniais skaičiais, išmoksta aritmetikos veiksmų, sudarančių sudėtingą pakopinę struktūrą. Kiekvienas paprastas veiksmas yra sudėtingesnių veiksmų sudėtinis elementas, todėl svarbu, kad kiekvieną paprastesnį veiksmą mokinys išmoktų atlikti greitai ir be klaidų, „negalvodamas“. Daugumai mokinių aritmetikos veiksmų atlikimo sunkumai yra pagrindinė priežastis, trukdanti mokytis ne tik aritmetikos, bet ir kitų matematikos temų. Todėl svarbu ieškoti būdų, metodų ir priemonių, kaip padėti mokiniams įveikti šiuos kliuvinius. Manoma, kad mokymo(si) turinį perkeliant į elektroninę erdvę, pavyks rasti būdų, leisiančių veiksmingiau organizuoti mokymo(si) procesą. Vis dažniau kalbama apie virtualiąsias mokymo(si) aplinka, kur mokymo(si) turinys pateikiamas nepriklausomais medžiagos gabalėliais – virtualiaisiais mokymo(si) objektais. Šiuo disertaciniu tyrimu siekta nustatyti, kokios yra virtualiųjų mokymo(si) objektų taikymo galimybės ir veiksmingumas, ugdant mokinių gebėjimus atlikti aritmetikos veiksmus IV–V klasėse. / In all times arithmetic has been an important subject at school: pupils familiarize themselves with natural and fractional numbers, learn arithmetic operations, acquire computation abilities. Actions of teaching and learning mathematics make up a complicated tiered structure. Every simple operation is a constituent of more complicated operations; therefore, the pupil has to learn to perform these operations quickly and without mistakes, „without thinking“. For the majority of pupils difficulties in performing arithmetic operations is the main reason hindering not only to learn arithmetic but also other topics of mathematics. Therefore, it is important to search for the ways, methods and means facilitating pupils to cope with these hindrances. It is supposed that as the content of teaching and learning moves to the electronic space, ways enabling to control and manage the teaching and learning process will be successfully found. More often virtual teaching and learning environments are mentioned, where the content of teaching and learning is presented in independent pieces of teaching material – virtual teaching and learning objects This dissertation research was designed to determine what is a virtual teaching and learning objects the application possibilities and efficiency, developing pupils' abilities to perform arithmetic operations in forms 4 and 5.

Bakalauro darbą „Elektroninės mokymo(si) priemonės „Fizika lentelėse“ sukūrimas ir analizė“ sudaro įvadas, 3 skyriai, išvados, priedai, 1 kompaktinis diskas. Darbo apimtis 35 lapai. Darbe pateikiama 19 paveikslų. Įvade pateikiamas darbo aktualumas, tikslai ir uždaviniai. Pirmajame skyriuje aprašomas apibendrinančios medžiagos panaudojimas ir reikalingumas mokyme ir mokymesi, išanalizuota literatūra, atlikta internetinių mokomųjų priemonių apžvalga, parašytas apibendrinimas. Antrajame skyriuje pristatomos darbe naudojamos informaciniės technologijos. Trečiajame skyriuje aprašomi elektroninės mokymo(si) priemonės „Fizika lentelėse“ metodiniai reikalavimai, svetainės pateikimas ir apipavidalinimas, svetainės struktūra ir navigacija, bei nurodomas svetainės turinys. Atlikta trumpa svetainės turinio apžvalga. Elektroninė mokymo(si) priemonė „Fizika lentelėse“ bus patalpinta ir naudojama fizikos mokyklos „Fotonas“ internetiniame puslapyje. Naudojantis internetiniais paieškos varikliais nesunkiai randama internete. / The batchelor„s thesis „Measure of E-ducation (E-study) “Physics tables” establishment and analysis” consists of an introduction, 3 chapters, conclusions, attachments, a compact disc. This study consists of 35 pages including addendum, 19 pictures. Introduction contains: relevance of the research, goals and objectives. In the first section the usage as well as the necessity of presumptive material in teaching and learning is described, the literature is reviewed, the overview of online educational tools is done, and summation is written. The second section presents the information technology used in the present paper. The third section describes the electronic training means "Physics Tables" methodological requirements, the website presentation and design, site structure and navigation as well as shows the content of the site. A brief overview of the site content was conducted. E – education tool "Physics tables“ will be placed and used in the school of physics „Fotonas“ website. Using online search engines easily found on the Internet.