Static abnormal grain growth (SAGG) was studied in Al-Mg alloy AA5182 sheet by varying four processing parameters: deformation temperature, strain rate, annealing temperature, and annealing time. SAGG is a secondary recrystallization process related to geometric dynamic recrystallization (GDRX) and requires both deformation at elevated temperature and subsequent static annealing. A minimum temperature is required for both SAGG and GDRX. Recrystallized grains only develop at strains larger than the critical strain for SAGG, [epsilon]SAGG. The size of the recrystallized grains is inversely related to and controlled by the density of SAGG nuclei, which increases as local strain increases. The results of this study suggest that SAGG is controlled by two thermally-activated mechanisms, dynamic recovery and recrystallization. During deformation, dynamic recovery increases as deformation temperature increases or strain rate decreases, increasing the critical strain for SAGG. SAGG is subject to an incubation time that decreases as annealing temperature increases. SAGG can produce grains large enough to reduce yield strength by 20 to 50 percent. The results of this study suggest strategies for avoiding SAGG during hot-metal forming operations by varying processing conditions to increase [epsilon]SAGG. / text

Η εργασία ασχολείται με διάφορα εμπορικά εργαλεία αξιολόγησης λογισμικού (τόσο ανοιχτού κώδικα όσο και επί πληρωμή). Επίσης έγιναν δοκιμαστικές αναλύσεις μεγάλων εμπορικών προγραμμάτων και συγκριτικές αξιολογήσεις. Τέλος στα πλαίσια της εργασίας αναπτύχθηκε εργαλείο στατικής ανάλυσης λογισμικού. / This thesis is occupied with various tools for software analysis(both open source and paid tools).Also large software programms have been tested and analyzed and results evaluated and compared.Finally a static software analysis tool has been developed.

Η παρούσα διπλωματική εργασία πραγματεύεται την στατική και αντισεισμική μελέτη και σχεδιασμό του Β’ Κτηρίου Διοίκησης Ε.Α.Π. Ο φέροντας οργανισμός του συγκεκριμένου κτηρίου συνίσταται από μεταλλική ανωδομή με σύμμικτες πλάκες και υπόγειο οπλισμένου σκυροδέματος. Η ανάλυση έγινε βάση των αρχών που επιβάλλουν οι Ευρωκώδικες 1, 3, 4 και ο Ελληνικός Κανονισμός Ωπλισμένου Σκυροδέματος (Ε.Κ.Ω.Σ.) καθώς και ο Ελληνικός Αντισεισμικός Κανονισμός (Ε.Α.Κ.). Η ανάλυση έγινε από τα προγράμματα FESPA, που έχει αναπτυχθεί από την εταιρία LH ΛΟΓΙΣΜΙΚΗ, και STRAD, STEEL, που έχουν αναπτυχθεί από την εταιρία 4Μ. Η εργασία αποτελείται από έξι(6) κεφάλαια. Στο πρώτο κεφάλαιο γίνεται μια σύντομη εισαγωγή στο οπλισμένο σκυρόδεμα και τον δομικό χάλυβα. Παρουσιάζονται οι δυνατότητες καθώς και οι αδυναμίες του κάθε υλικού κατασκευής. Επίσης, γίνεται μια συνοπτική περιγραφή της κατασκευής που πρόκειται να αναλυθεί και να διαστασιολογηθεί. Στο δεύτερο κεφάλαιο γίνεται η παρουσίαση των βασικών αρχών των Ευρωκώδικων 1,3,4, του ΕΚΩΣ και του ΕΑΚ σύμφωνα με τις οποίες γίνεται η ανάλυση και διαστασιολόγηση της κατασκευής. Στο τρίτο κεφάλαιο παρουσιάζονται τα προγράμματα FESPA, STRAD και STEEL με τα οποία πραγματοποιείται η ανάλυση και η διαστασιολόγηση της κατασκευής. Παρουσιάζονται κατά σειρά η μέθοδος με την οποία εκτελούν την στατική, αλλά και τη δυναμική-φασματική ανάλυση, οι συμβάσεις αξόνων και μελών, οι έλεγχοι που πραγματοποιούνται κ.α. Στο τέταρτο κεφάλαιο, γίνεται η εύρεση των απαραίτητων για την ανάλυση δεδομένων σύμφωνα με τις αρχές που δίνονται στο κεφάλαιο 2. Κατ’αρχήν παρουσιάζεται το μοντέλο της κατασκευής. Έπειτα, προσδιορίζονται κατασκευαστικά στοιχεία όπως το πάχος πλακών, προσδιορίζονται τα φορτία λόγω ίδιου βάρους, φορτία επικαλύψεων και τοιχοποιίας, ωφέλιμα φορτία, φορτία χιονιού και ανέμου. Καθορίζονται τα φασματικά δεδομένα που απαιτούνται για την δυναμική-φασματική ανάλυση της κατασκευής. Τέλος, γίνεται αναφορά στο τρόπο που έγινε η προσομοίωση και εξιδανίκευση του φορέα και στις παραδοχές που χρειάστηκαν για να γίνει. Στο πέμπτο κεφάλαιο-που ίσως είναι και το ουσιαστικότερο όλων-γίνεται ο έλεγχος και η διαστασιολόγηση της κατασκευής με κάθε πρόγραμμα ξεχωριστά. Συγκεκριμένα γίνεται ο έλεγχος των μελών, από δομικό χάλυβα και από οπλισμένο σκυρόδεμα, σε επίπεδο διατομής και μέλους καθώς και ο αναλυτικός έλεγχος των δυσμενέστερων μελών, γίνονται οι έλεγχοι λειτουργικότητας και παραμορφώσεων (όπως έλεγχος επιρροής φαινομένων δεύτερης τάξης και έλεγχος βλαβών) και τέλος παρουσιάζεται η ανάλυση και η διαστασιολόγηση του υπογείου και της θεμελίωσης. Στο έκτο και τελευταίο κεφάλαιο γίνεται η επίλυση των σύμμικτων πλακών της οροφής ισογείου και της οροφής α’ ορόφου. Συγκεκριμένα γίνεται η επιλογή της γεωμετρίας των σύμμικτων πλακών και ο έλεγχος τους σε κάμψη, εγκάρσια και διαμήκη διάτμηση, λειτουργικότητας και ρηγμάτωσης. Επειδή τα συγκεκριμένα προγράμματα δεν επιλύουν σύμμικτες πλάκες, η επίλυσή τους έγινε στο χέρι και στη συνέχεια τα αποτελέσματα δόθηκαν στα προγράμματα ώστε να γίνει η επίλυση όλου του φορέα. / This project concerns a static-earthquake resistant construction of a building in the University of Patras.

This dissertation develops technology for microfluidic point-of-care immunoassay devices. This research (2004–2007) improved microfluidic immunoassay performance by reducing reagent consumption, decreasing analysis time, increasing sensitivity, and integrating processes using a lab-on-a-chip. Estimates show that typical hospital laboratories can save $1.0 million per year by using microfluidic chips. Our first objective was to enhance mixing in a microfluidic channel, which had been one of the main barriers to using these devices. Another goal of our studies was to simplify immunoassays by eliminating surfactants. Manufacturers of latex immunoassays add surfactants to prevent non-specific aggregation of microspheres. However, these same surfactants can cause false positives (and negatives) during diagnostic testing. This work, published in Appendix A (© 2006 Elsevier) shows that highly carboxylated polystyrene (HCPS) microspheres can replace surfactants and induce rapid mixing via diffusion in microfluidic devices. Our second objective was to develop a microfluidic device using fiber optics to detect static light scattering (SLS) of microspheres in Appendix B (© 2007 Elsevier). Fiber optics were used to deliver light emitting diode (LED) or laser light. A miniature spectrometer was used to measure 45° forward light scattering collected by optical fiber. Latex microspheres coated with PR3 proteins were used to test for the vasculitis marker, anti-PR3. No false negatives or positives were observed. A limit of detection (LOD) of 50 ng mL⁻¹ was demonstrated. This optical detection system works without fluorescence or chemiluminescence markers. It is cost effective, small, and re-usable with simple rinsing. The final objective in this dissertation, published in Appendix C (© 2007 Elsevier), developed a multiplex immunoassay. A lab-on-a-chip was used to detect multiple antibodies using microsphere light scattering and quantum dot (QD) emission. We conjugated QDs onto microspheres and named this configuration “nano-on-micro” or “NOM”. Upon radiation with UV light, strong light scattering is observed. Since QDs also provide fluorescent emission, we are able to use increased light scattering for detecting antigen-antibody reactions, and decreased QD emission to identify which antibody is present.

Nonadhesive hydrate slurries have been shown to exhibit low viscosities in a field-scale flow loop when formed under appropriate conditions. The factors that favor formation of low-viscosity hydrate slurries include high Reynolds Number and Capillary Number, and high mass transfer and heat transfer rates. High liquid loading and high superficial fluid velocities are found to be conducive to the formation of low viscosity hydrate slurries. Dispersed bubble flow has been observed to facilitate flowable hydrate slurry production. Alternatively, the formation of nonadhesive hydrates at moderate superficial velocity is possible when a static mixer is used upstream of the hydrate formation location. For certain fields, low-viscosity hydrate slurry technology could eliminate the need for insulation and hydrate inhibitor chemicals (revised version of ICGH 2008 paper 5818) .

There has recently been a resurgence in interest in techniques for effective programming of multi-core computers. Most programmers find general-purpose concurrent programming to be extremely difficult. This difficulty severely limits the number of applications that currently benefit from multi-core computers. There already exist many concurrent solutions for the class of regular applications, which include various algorithms for linear algebra. For the class of irregular applications, which operate on dynamic and pointer- and graph-based structures, efficient concurrent solutions have so far remained elusive. Dataflow analysis applications, which are often found in compilers and program analysis tools, have received particularly little attention with regard to execution on multi-core machines. Operating on the theory that the Actor model, which structures computations as systems of asynchronously-communicating entities, is a more appropriate method for representing irregular algorithms than the shared-memory model, this work presents a concurrent Actor-based formulation of the IFDS, or Interprocedural Finite Distributive Subset, dataflow analysis algorithm. The implementation of this algorithm is done using the Scala language and its Actors library. This algorithm achieves significant speedup on multi-core machines without using any optimistic execution. This work contributes to Actor research by showing how the Actor model can be practically applied to a dataflow analysis problem. This work contributes to static analysis research by showing how a dataflow analysis algorithm can effectively make use of multi-core machines, allowing the possibility of faster and more precise analyses.

Šiame dokumente aprašytas darbas susideda iš trijų dalių. Pirmoje dalyje atlikome inžinerinę programinio kodo valdymo sistemos „SourceHQ“ analizę ir projektavimą. Palyginome rinkoje esančius analogus, jų privalumus ir trūkumus. Glaustai pateikėme architektūrą ir aprašėme pasirinktus realizavimo sprendimus. Dokumento antroje dalyje ištyrėme jau egzistuojančias statinės kodo analizė taisykles ir pasiūlėme jas išplėsti naujomis. Aprašėme analizei naudojamus įrankius, jų veikimo principus ir pateikiamus rezultatus. Paskutinėje darbo dalyje ištyrėme ir eksperimentiškai išbandėme naujai realizuotas mūsų pasiūlytas taisykles. Palyginome testų rezultatus programų veikimo našumo charakteristikos aspektais. Įrodėme mūsų programinio kodo statinės analizės taisyklės privalumus. / This final master’s thesis consists of three major parts. The first section covers engineering aspects of source code management system called “SourceHQ” that we developed, including its analysis and design details. We will provide key details and basis of chosen technologies, business analysis, and design decisions as well as discuss system functionality and its future prospects. The second part is dedicated to testing and ensuring system quality, which led us to design and develop custom static source code analysis rules. We will formulate and explain their potential use and benefits. We will describe additional tools and methods being used and provide main results of static source code analysis. In the final part of our work we go deeper into static source code analysis. We perform experiments based on our designed and developed custom rules on various .NET Framework applications and systems. We cover major performance benefits and drawbacks of every rule separately and display how this approach lets developers optimize their source code in an early development stage. We provide research data based on extensive experiments and conclude how using FxCop tool provided with our improved custom code analysis rules can automatically discover and suggest improvements in CIL code.

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.

Šiuo metu daugumoje automatinio valdymo sistemų struktūrų yra įtaisų kurie pagerina šių sistemų kokybines charakteristikas. Šie įtaisai yra vadinami reguliatoriais. Reguliatoriai formuoja objekto valdymo dėsnį, todėl panaudojant reguliatorius galima originalios sistemos valdymo kokybinius parametrus nustatytu tikslumu priartinti prie norimos sistemos charakteristikų. Šio darbo tikslas ištirti elektromechaninės greičio stabilizavimo sistemos dinamikos kokybės pagerinimo metodą pagrįstą keičiamos struktūros greičio reguliatoriumi. Šiame darbe buvo sudarytas elektromechaninės greičio stabilizavimo sistemos su keičiamos struktūros reguliatoriumi imitacinis modelis MATLAB/SIMULINK programa. Pagal tiesioginį kokybės rodiklį – reguliavimo trukmę, buvo nustatyta geriausioji greičio reguliatoriaus valdymo dėsnio perjungimo momento priklausomybė nuo greičio nustatymo signalo bei statinės apkrovos, tuo užtikrinant geriausią elektromechaninės greičio stabilizavimo sistemos dinamikos kokybę. Tiriamos sistemos statinės apkrovos nustatymui pereinamajame režime pritaikytas Luenbergerio stebiklis. Gauti rezultatai yra universalūs ir buvo sėkmingai pritaikyti nuolatinės srovės elektros pavarai, panaudojant programuojamą duomenų lentelę Lookup Table, imituojant automatinį reguliatoriaus valdymo dėsnio keitimą iš proporcinio (P) į proporcinį integruojantį (PI). / Currently in the majority of automatic control systems are the devices that improve the qualitative characteristics of these systems. These devices – controllers. Controllers form the object's control law, so using controllers is possible quality parameters of the original control system to place closer to the desired characteristics of the system. The aim of this work is the investigation of the dynamical quality improvement method of the electromechanical velocity stabilization system based on the variable structure velocity controller. The MATLAB/SIMULINK model of the electromechanical speed stabilization system with variable structure controller has been created. According to the quality indicator – settling time, it has been determined the control law switching parameter dependence on the static load and the command input ensuring the best dynamical quality of the electromechanical speed stabilization system. The Luenberger observer has been applied for the static load estimation during the transient regime of the electromechanical speed stabilization system. The obtained results are universal and have been successfully applied for the DC electric drive model simulaiting the automatic control law change from the proportional (P) to the proportional integral (PI) using Lookup Table.

Vaikų ir paauglių fizinio pajėgumo lygis mažėja (Tomkinson et al., 2003; Tomkinson et al., 2007). Tai kelia nerimą, todėl kad šiose amžiaus grupėse fizinio pajėgumo lygis yra glaudžiai susijęs su fizine ir protine sveikata, kaip trumpalaike, taip ir ilgalaike (Malina, 1996; Ortega et al., 2008). Mokslininkai padarė išvadą, kad visi vaikai, ir turintys ir neturintys sveikatos sutrikimų, turi būti skatinami didesniam bendram fiziniam aktyvumui, bet ypač vidutinio ir didelio intensyvumo fiziniam aktyvumui (Kao et al., 2009). Pagal „Kūno kultūros silpnesnės sveikatos moksleiviams metodines rekomendacijas“ vaikai yra skirstomi i medicinines fizinio pajėgumo grupes, kurios atitinka moksleivio sveikatos būklę, fizinį išsivystymą, svarbiausių organizmo sistemų ir organų funkcinę būklę bei fizinį parengtumą. Nėra tirta, ar tikrai moksleivių, priskirtų paruošiamajai grupei, fizinis pajėgumas yra mažesnis, nei tų, kurie neturi objektyvios priežasties gauti mažesnį fizinį krūvį per kūno kultūros pamokas. Tam, kad sužinoti, kas turi įtakos fiziniam pajėgumui, papildomai buvo išskirta sportuojančiųjų moksleivių grupė ir vertinamas bendro fizinio aktyvumo ir skirtingo jo intensyvumo ryšys su fiziniu pajėgumu ir sveikata. Hipotezė: Moksleivių fizinis pajėgumas labiau priklausys nuo fizinio aktyvumo, nei nuo sveikatos būklės, kurią atspindi priklausymas pagrindinei ar parengiamajai (medicininei fizinio pajėgumo) grupei. Tyrimo tikslas: išanalizuoti moksleivių fizinio pajėgumo komponentų... [toliau žr. visą tekstą] / Longitudinal studies show a decline in physical fitness level in children and adolescents (Tomkinson et al., 2003; Tomkinson et al., 2007). It causes concern about youth health because the level of physical fitness of this age groups is closely related to physical and mental health (Malina, 1996; Ortega et al., 2008). Both healthy children and children with health problems should be encouraged to engage in more physical activity especially moderate or vigorous physical activity (Kao et al., 2009). According to „Physical activity for weaker health schoolchildren recommendations” (Švedas et al.., 2003), schoolchildren are divided into medical physical fitness groups. These groups are formed according to health condition, physical development, main body system functioning, and physical fitness level. There are no data about real physical fitness level of preparation group compared with main group schoolchildren who have no reason to get lower loading during physical education. In our study we separated school children, participating in sport activity, and measured total physical activity, different intensity of physical activity, and their association with physical fitness and health. Hypothesis: the physical fitness of school children more dependent on physical activity than health condition or belonging to lower physical fitness group. Aim of research: to analyze the association between schoolchildren physical fitness components, physical activity and health according to... [to full text]