Analiza potencijala izgradnje energetskih postrojenja loženih različitim tipovima biomase u Hrvatskoj i odabir lokacija

Tema diplomskog rada je analiza potencijala izgradnje energetskih postrojenja loženih različitim tipovima biomase, te odabir makro-lokacija za izgradnju energetskih postrojenja. \Na odabranim makro-lokacijama potrebno je izvršiti analizu tehničkog i energetskog potencijala, te cijene biomase pri čemu se na osam lokacija vrši analiza cijena šumske biomase dok se na preostale dvije lokacije analizira cijena poljoprivredne biomase na pragu elektrane. Uvodni dio diplomskog rada sadrži općenite podatke o biomasi kao što su podjela biomase, transformacija biomase te energetske vrijednosti različitih tipova biomase. Također je u uvodu napravljena usporedba između potrošnje biomase i plinskog goriva u Hrvatskoj u periodu od 1990. do 2006. godine. Metodologija izračuna tehničkog i energetskog potencijala, te cijene biomase na pragu elektrane za različite tipova biomase dana je u drugom dijelu rada. Pored ovoga opisan je i postupak izrade ekonomske analize za odabrane makro-lokacije. U završnom dijelu rada dani su rezultati za tehnički i energetski potencijal različitih tipova biomase. Pored potencijala izračunat je profil ponude biomase, te cijena biomase na pragu elektrane. Na samom kraju rada prikazani su rezultati iz ekonomske analize za tri odabrane lokacije na kojima se planira izgradnja energetskih postrojenja loženih na slamu, kukuruzovinu i na šumske ostatke

A 100% renewable energy system in the year 2050: The case of Macedonia

The most important problems the energy sector faces in Macedonia are an unfavourable energy mix with a high prevalence of lignite, a strong dependence on energy import, poor condition of the energy system and inefficiency in energy production and use. This paper investigates the prospects for realization of the 100% renewable energy system in Macedonia by making use of the EnergyPLAN model. Analysis was conducted for two renewable scenarios designed for the years 2030 and 2050. First scenario, the 50% renewable energy system, has been created for the year 2030 and represents the first step towards the 100% renewable energy future of Macedonia. The second scenario has been designed for the 100% renewable energy system based only on the renewable energy sources in the year 2050. Special attention in the design of these systems has been given to intermittent renewable energy sources and to storage technologies. The analysis reveals that at the moment the 50% renewable energy system seems much more likely than the 100% renewable energy system, but with additional energy efficiency measures, which will lead to a decrease of consumption and with installation of new generation capacities this goal can be easily achieved

Fragility and reliability analyses of soil -pile -bridge pier interaction

U radu je prikazana procedura evaluacije seizmičkih performansi interakcije šip-tlo inkrementalnom nelinearnom dinamičkom analizom (INDA -Incremental Nonlinear Dynamic Analysis). Ulazni signal u sistemu je tretiran preko generisanih veštačkih akcelerograma, a koji su dodatno procesirani po slojevima tla do osnovne stene. Postprocesiranje INDA analiza izvršeno je posebno za stub, a posebno za šip, tako da su konstruisane krive PGA=f(DR) u kapacitativnom domenu. Za ovako konstruisane krive određeni su performansni nivoi, a na osnovu određenih DR i PGA parametara sprovedene su regresione analize. Krive povredljivosti su konstruisane na osnovu rešenja regresione analize i teorije verovatnoće log-normalne raspodele. Takođe, konstruisane su i krive pouzdanosti na osnovu rešenja analize povredljivosti. Metodološki postupak za analizu seizmičkih performansi, prezentovan u ovom istraživanju, omogućava integrisano kvantitativno-kvalitativno razmatranje i evaluaciju kompleksne interakcije konstrukcija-tlo (SFSI -Soil-Foundation-Structure Interaction).The purpose of this paper is to present the methodology for performance-based seismic evaluation of soil-pile-bridge pier interaction using the incremental nonlinear dynamic analysis (INDA). The system's input signal was treated through the generated artificial accelerograms which were subsequently processed by soil layers and for the bedrock. The INDA analysis was post processed separately for the pier and for the pile, so that the constructed PGA=f(DR) curves are in the capacitive domain. For these curves the authors identified the performance levels, while the regression analyses were conducted based on the specific DR and PGA parameters. Fragility curves were constructed based on the solutions of regression analysis and the probability theory of log-normal distribution. Based on the results of fragility analysis, reliability curves were also constructed. The methodological procedure for seismic performance analysis presented in this study provides an integrated quantitative-qualitative consideration and evaluation of the complex soil-foundation-structure interaction (SFSI)

Buckling analysis of 3D model of slender pile in interaction with soil using finite element method

U radu je prikazano modeliranje i analiza rezultata stabilnosti vitkih šipova primenom metode konačnih elemenata. Formulisan je koncept za modifikovanu analizu stabilnosti 3D modela šip-naglavna ploča-tlo formiran od solid konačnih elemenata za dva tipa modela tla: jednoslojni i dvoslojni. Veza šip-tlo je modelirana primenom kontaktnih link elemenata. Izrazi za nivo normalizovane vrednosti kritične sile Pcr/PE 3D modela šip-naglavna ploča-tlo izvedeni su primenom regresionih analiza za stepenu funkciju. Na osnovu sprovedenih numeričkih testova i regresionih analiza izvedeni su izrazi za koeficijent dužine izvijanja b u funkciji dužine šipa, krutosti šipa i krutosti tla. Istraživanjem je pokazano da je primena sofisticiranih matematičkih modela i numeričkih analiza opravdana i neophodna u cilju kvalitetnijeg uvida u ponašanje vitkog šipa sa aspekta stabilnosti. Ukazano je na kompleksan oblik izvijanja vitkog šipa sa većim brojem polutalasa.The paper describes the modelling and stability analysis of slender piles using finite element method. The concept of a modified stability analysis of 3D model pile-soil-pile cap is formulated; it is formed from solid finite element models for the two types of soil, and a single-pile. Connection in pile-soil contact is modelled using link elements. The terms of the level of normalized critical load Pcr/PE 3D model of pile-soil-pile cap are derived using regression analysis of the power function. On the basis of performed numerical tests and regression analyses expressions are derived for the buckling length coefficient b as a function of pile length, pile stiffness and soil stiffness. Research has shown that the use of sophisticated mathematical models and numerical analysis is justified and necessary in order to gain better insight into the behaviour of slender piles in terms of stability. The paper points to the complex shape of the buckling of slender piles with a number of half waves

Buckling analysis of 3D model of slender pile in interaction with soil using finite element method

U radu je prikazano modeliranje i analiza rezultata stabilnosti vitkih šipova primenom metode konačnih elemenata. Formulisan je koncept za modifikovanu analizu stabilnosti 3D modela šip-naglavna ploča-tlo formiran od solid konačnih elemenata za dva tipa modela tla: jednoslojni i dvoslojni. Veza šip-tlo je modelirana primenom kontaktnih link elemenata. Izrazi za nivo normalizovane vrednosti kritične sile Pcr/PE 3D modela šip-naglavna ploča-tlo izvedeni su primenom regresionih analiza za stepenu funkciju. Na osnovu sprovedenih numeričkih testova i regresionih analiza izvedeni su izrazi za koeficijent dužine izvijanja b u funkciji dužine šipa, krutosti šipa i krutosti tla. Istraživanjem je pokazano da je primena sofisticiranih matematičkih modela i numeričkih analiza opravdana i neophodna u cilju kvalitetnijeg uvida u ponašanje vitkog šipa sa aspekta stabilnosti. Ukazano je na kompleksan oblik izvijanja vitkog šipa sa većim brojem polutalasa.The paper describes the modelling and stability analysis of slender piles using finite element method. The concept of a modified stability analysis of 3D model pile-soil-pile cap is formulated; it is formed from solid finite element models for the two types of soil, and a single-pile. Connection in pile-soil contact is modelled using link elements. The terms of the level of normalized critical load Pcr/PE 3D model of pile-soil-pile cap are derived using regression analysis of the power function. On the basis of performed numerical tests and regression analyses expressions are derived for the buckling length coefficient b as a function of pile length, pile stiffness and soil stiffness. Research has shown that the use of sophisticated mathematical models and numerical analysis is justified and necessary in order to gain better insight into the behaviour of slender piles in terms of stability. The paper points to the complex shape of the buckling of slender piles with a number of half waves

Multidisciplinary Approach to the Assessment of Seismic Performances and Rehabilitation of Bridges: Nonlinear Analyses, Probability Theory and Optimization Theory

AbstractThe paper presents a multidisciplinary approach to the assessment of seismic performances based on the Performance-Based Earthquake Engineering (PBEE), taking into account the multi-criteria optimization theory in analyzing the priority methods for bridge rehabilitation/strengthening. One bridge model was subjected to nonlinear static pushover analyses (NSPA), target displacement analyses using the spectrum capacity method (CSM), vulnerability analyses, and reliability analyses, while for a damaged bridge, in addition to be considered using the above methods, was also analyzed using the VIKOR method of multi-criteria optimization. Seismic performances were determined based on monitoring the system's plastification and analyzing the relevant parameters for the level of target displacement, such as target displacement, total shear force, spectral displacement, spectral acceleration, vibration period, damping and ductility. The phases of damage were considered using the probabilistic analysis of vulnerability and reliability: slight, moderate, extensive and complete, as a function of system ductility