The Advanced Encryption Standard (AES) was developed by Joan Daemen and Vincent Rjimen and endorsed by the National Institute of Standards and Technology in 2001. It was designed to replace the aging Data Encryption Standard (DES) and be useful for a wide range of applications with varying throughput, area, power dissipation and energy consumption requirements. Field Programmable Gate Arrays (FPGAs) are flexible and reconfigurable integrated circuits that are useful for many different applications including the implementation of AES. Though they are highly flexible, FPGAs are often less efficient than Application Specific Integrated Circuits (ASICs); they tend to operate slower, take up more space and dissipate more power. There have been many FPGA AES implementations that focus on obtaining high throughput or low area usage, but very little research done in the area of low power or energy efficient FPGA based AES; in fact, it is rare for estimates on power dissipation to be made at all. This thesis presents a methodology to evaluate the energy efficiency of FPGA based AES designs and proposes a novel FPGA AES implementation which is highly flexible and energy efficient. The proposed methodology is implemented as part of a novel scripting tool, the AES Energy Analyzer, which is able to fully characterize the power dissipation and energy efficiency of FPGA based AES designs. Additionally, this thesis introduces a new FPGA power reduction technique called Opportunistic Combinational Operand Gating (OCOG) which is used in the proposed energy efficient implementation. The AES Energy Analyzer was able to estimate the power dissipation and energy efficiency of the proposed AES design during its most commonly performed operations. It was found that the proposed implementation consumes less energy per operation than any previous FPGA based AES implementations that included power estimations. Finally, the use of Opportunistic Combinational Operand Gating on an AES cipher was found to reduce its dynamic power consumption by up to 17% when compared to an identical design that did not employ the technique.

Desiccant cooling is a technology that, based on a open psychrometric cycle, is able to provide cooling using heat as the main energy carrier. This technology uses a considerably smaller amount of electricity than refrigerators based on the vapor-compression cycle, which is an electricity driven cycle. Electricity is often more expensive than other types of energy and has CO2 emissions associated with its generation , so desiccant cooling has the potential of achieving both economic and environmental benefits. In addition to this, the heat the desiccant cooling cycle needs to work can be supplied at relative low temperatures, so it can use heat coming from the district heating grid, from a solar collector or even waste heat coming from industries. The system which will be studied in this report is a desiccant cooling system based on the model designed by the company Munters AB. The systems relies on several components: a desiccant rotor, a rotary heat exchanger two evaporative humidifiers and two heating coils. It is a flexible system that is able to provide cooling in summer and heat during winter. This study performs a deep economic and environmental analysis of the desiccant cooling systems, comparing it with traditional vapor compression based systems: In order to achieve this objective a user-friendly software was created, called the DCSS – Desiccant Cooling Simulation Software – that simulates the operation of the system during a year and performs automatically all the necessary calculations. This study demonstrates that economic savings up to 54% percent can be achieved in the running costs of desiccant cooling systems when compared to traditional compressor cooling systems, and  reductions up to39% in the CO2 emissions. It also demonstrates that desiccant cooling is more appropriate in dry climate zones with low latent heat generation gains. In addition to that, the DSCC software created will help further studies about the physical, economic and environmental feasibility of installing desiccant cooling systems in different locations.

The Advanced Encryption Standard (AES) was developed by Joan Daemen and Vincent Rjimen and endorsed by the National Institute of Standards and Technology in 2001. It was designed to replace the aging Data Encryption Standard (DES) and be useful for a wide range of applications with varying throughput, area, power dissipation and energy consumption requirements. Field Programmable Gate Arrays (FPGAs) are flexible and reconfigurable integrated circuits that are useful for many different applications including the implementation of AES. Though they are highly flexible, FPGAs are often less efficient than Application Specific Integrated Circuits (ASICs); they tend to operate slower, take up more space and dissipate more power. There have been many FPGA AES implementations that focus on obtaining high throughput or low area usage, but very little research done in the area of low power or energy efficient FPGA based AES; in fact, it is rare for estimates on power dissipation to be made at all. This thesis presents a methodology to evaluate the energy efficiency of FPGA based AES designs and proposes a novel FPGA AES implementation which is highly flexible and energy efficient. The proposed methodology is implemented as part of a novel scripting tool, the AES Energy Analyzer, which is able to fully characterize the power dissipation and energy efficiency of FPGA based AES designs. Additionally, this thesis introduces a new FPGA power reduction technique called Opportunistic Combinational Operand Gating (OCOG) which is used in the proposed energy efficient implementation. The AES Energy Analyzer was able to estimate the power dissipation and energy efficiency of the proposed AES design during its most commonly performed operations. It was found that the proposed implementation consumes less energy per operation than any previous FPGA based AES implementations that included power estimations. Finally, the use of Opportunistic Combinational Operand Gating on an AES cipher was found to reduce its dynamic power consumption by up to 17% when compared to an identical design that did not employ the technique.

Two different Statistical Energy Analysis (SEA) models of a single turbo-prop engine propeller aircraft have been developed to predict the interior and exterior noise levels. The commercial software VA One is used for the analysis. First model is a pure SEA model developed with ribbed plates on the aircraft exterior. Second model is a hybrid model which employs finite element (FE) modeling of aircraft components with low modal density. These models have been analyzed for three different flight conditions, namely, take-off, cruise and climb for three different damping loss factors in each condition. Wind tunnel measurements are used to estimate the turbulent boundary layer (TBL) information on the surface of the aircraft. Propeller noise together with TBL loading are then used as the excitation for the models. Flow paths of energy are identified and cabin interior noise levels are predicted for the developed models. Results of analyses are comparatively evaluated.

Two sample statistical energy analysis (SEA) models are generated for a section of the fuselage panel of an aircraft, namely the uniform panel model which includes the frames and stringers, and the ribbed panel model in which the frames and stringers are smeared into the skin. Turbulent boundary layer (TBL) excitation is used as the primary acoustic excitation source. Stress levels are estimated from the average velocity data of the panels. The stress results are found comply with those obtained by the AGARD method. Effect of radiation from panels to exterior and interior of the sample skin panel as well as the pressurization of the skin panels are investigated separately to analyze their effects on the stress levels. The method is then used in the analysis of center fuselage skin panels on a basic training aircraft. Two models are generated for the aircraft analysis, namely the complete aircraft model and the simplified model which excludes the wings and the empennage. In addition to TBL, propeller noise is used as the primary acoustic excitation source. The effects of the wings and the empennage on the stress levels in the center fuselage skin panels are also investigated along with the radiation from panels to the exterior and interior of the aircraft and pressurization of the pilot cabin.

A poly-generation system can be defined as the simultaneous and collocated generation of two or more energy supply types, aimed to maximize the utilization of the thermodynamic potential (efficiency) of the consumed energy resources. A Polygeneration system may involve co-generation (power and heat) or tri-generation (power, heat, and cold) processes and may also be connected to a district energy system. A poly-generation plant reclaims heat in a useful form that would be wasted otherwise in separate electricity and heat (and chilled water in some cases) generating systems. By this way a poly-generation plant provides a variety of benefits including improved efficiency and fuel savings, reduction of the primary energy demand total cost of utility service and unit fuel cost, independency for energy and protection of environment. With the overall efficiencies in the range of 70-90%, poly-generation systems are gaining popularity all around the world. including Turkey. In spite of all their potential benefits and increasing interest for poly-generation systems, there is not yet any rating, testing, metrication and classification guidelines and standards. It is indeed very important to rate the performance and energy savings potential, determine the heat and power outputs, estimate the system efficiency and the ratio of the split of the power produced between thermal and electric. These are the information which are hard to determine since there are not enough common test standards, rating standards and nor consensus-based terminology for combined heat and power systems in the world literature. Even the classification of the cogeneration systems is hardly globalized. Aim of this study is to develop a common procedure with respect to the above shortcomings for testing and rating poly-generation systems under realistic operating conditions with accurate formulae which will help to contribute energy and exergy economy by establishing a robust metrication standard based on new evaluation parameters. This study aims to find a procedure to evaluate a poly-generation system by establishing standard test methods and evaluation tools in terms of parameters like energy and exergy characteristics of thermal and electric loads, temperature demand and power split for determining operational characteristics of the system. This may be achieved by revising and expanding DIRECTIVE 2004/8/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL. A case study is expected to be based on a trigeneration power plant to be received within the framework of the EU FP6 HEGEL Poly-generation project, to be tested at METU, which has a capacity of 145 kW electric and 160 kW useful heat.

This research demonstrates the usage of numerical acoustics to model sound and vibrational energy propagation in HVAC ducts and plenums. Noise and vibration in HVAC systems propagates along three primary paths that can be classified as airborne direct, airborne indirect and structure-borne. The airborne direct path was simulated using acoustic FEM with special boundary conditions to handle the diffuse acoustic field loading and the baffled termination. The insertion loss for a number of different plenum geometries was compared to published measurement results. Results were in good agreement both below and above the cutoff frequency. Additionally, the airborne indirect path, often termed breakout noise by the HVAC community, was assessed using Statistical Energy Analysis (SEA). This path was examined experimentally by placing a loudspeaker inside the air handler and measuring the sound power transmitted through the walls. SEA results compared favorably with the measured results in one-third octave bands even at low frequencies. Finally, the structure-borne path was considered by exciting the walls of the aforementioned air handler using an electromagnetic shaker. The panel vibration and the sound power radiated from the panels were measured. Results were compared with the SEA with good agreement provided that SEA loss factors were determined experimentally.

Σκοπός της παρούσας εργασίας είναι η μελέτη της επίδρασης των εισροών στην ποιότητα του εδάφους των καλλιεργειών, στο οροπέδιο της κοινότητας Ομαλών στη νήσο Κεφαλληνία, μέσω της αξιοποίησης των στοιχείων που προκύπτουν από την δομή και την περιγραφή του συγκεκριμένου αγροτικού οικοσυστήματος. Η μελέτη έγινε σε βιολογικούς και συμβατικούς ελαιώνες και αμπελώνες και διήρκησε 1 χρόνο. Κατά την διάρκεια του χρόνου αυτού, πραγματοποιήθηκαν δειγματοληψίες από τα υπό μελέτη εδάφη και προσδιορίσθηκαν χημικές και βιολογικές ιδιότητες. Συγκεκριμένα προσδιορίστηκαν το pH, η Ικανότητα Ανταλλαγής Κατιόντων, η οργανική ουσία, η Ηλεκτρική αγωγιμότητα, ο φώσφορος, τα ανταλλάξιμα κατιόντα K, Na και Mg, το ολικό άζωτο, το βόριο τα νιτρικά και η εδαφική αναπνοή. Για την αξιοποίηση των αποτελεσμάτων των εδαφολογικών αναλύσεων ήταν απαραίτητη η γνώση των καλλιεργητικών πρακτικών που εφαρμόζονται στα αγροτεμάχια καθώς και οι ποσότητες των εισροών σε αυτά. Για το σκοπό αυτό πραγματοποιήθηκαν συνεντεύξεις σε αγρότες της περιοχής με την χρήση ερωτηματολογίων ανοιχτού τύπου. Από τα ερωτηματολόγια προέκυψε ότι η υψηλότερη ενεργειακή εισροή στο εδαφικό υποσύστημα είναι η κοπριά τόσο στην περίπτωση της βιολογικής καλλιέργειας όσο και συμβατικής καλλιέργειας ελιάς και αμπέλου. Η εντατική χρήση υψηλών ποσοτήτων κοπριάς συμβάλλει στην βελτίωση των χημικών και βιολογικών ιδιοτήτων του εδάφους αλλά εγκυμονεί κινδύνους για την ποιότητα του. / In the following research the effects of agroecosystem inputs on soil quality of crops at plateau Omala of Cephalonia island via the exploitation of elements that result through the study of the structure and the description of particular agroecosystem, were studied. The research had a duration of above 1 year, in which samplings from the soil and their chemical and biological attributes were not only realized but also evaluated concretely pH,Cation Exchange Capacity, organic matter, Electrical Conductivity, the phosphor, Exchangeable Cations K, Na and Mg, total N, NO3, the boron and the microbial rate, were measured. For the exploitation of results of soil analysis it was essential to have obtain knowledge of farming practices that is applied in the farmyards as well as the quantities of inputs. This aim was realised through interviews with farmers of the region with the use of open type questionnaires. The result of these questionnaires was that the higher energy input in the soil subsystem is manure. The intensive use of high quantities of manure contributes to the improvement of the chemical and biological attributes of soil but gestates dangers for soil quality.

Orientador: José Luz Silveira / Resumo: Neste trabalho são apresentados analises energética e econômica de duas configurações de plantas para a produção de biodiesel e biohidrogênio, integrando queima de parte do glicerol produzido no processo. O biodiesel estudado é produzido pela transesterificação de óleo de soja e o hidrogênio é produzido pela reforma a vapor do glicerol. O glicerol queimado é utilizado para produzir vapor de água necessário para o processo de reforma do glicerol. Na primeira configuração, o vapor para o processo de reforma é produzido num gerador de vapor convencional (caldeira convencional) que queima uma mistura de glicerol e gás natural. Na segunda configuração, considera-se uso de sistema de cogeração com microturbina a gás e caldeira de recuperação com queima suplementar de glicerol e gás natural com produção de vapor para o processo de reforma. A análise energética baseia-se numa planta que opera 7920 h/ano e produz 17820 m3/ano de biodiesel. Na configuração utilizando gerador de vapor convencional é possível produzir 222,47 ton/ano (312,53 Nm3/h) de hidrogênio; o sistema com cogeração produz 227,07 ton/ano (318,98 Nm3/h) de hidrogênio e além disso permite produzir 27,40 kW de eletricidade. A análise econômica é feita para as duas configurações consideradas visando alocar os custos de produção do biodiesel, hidrogênio e eletricidade. Além destes são determinados os custos de produção dos produtos intermediários, tais como glicerol e vapor de processo. Da análise de engenharia econômic... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

abstract: Building Envelope includes walls, roofs and openings, which react to the outdoor environmental condition. Today, with the increasing use of glass in building envelope, the energy usage of the buildings is increasing, especially in the offices and commercial buildings. Use of right glass type and control triggers helps to optimize the energy use, by tradeoff between optical and thermal properties. The part of the research looks at the different control triggers and its range that governs the use of electrochromic glass to regulate the energy usage in building. All different control trigger that can be possibly used for regulating the clear and tint state of glass were analyzed with most appropriate range. Its range was triggered such that 80% time of the glass is trigger between the ranges. The other building parameters like window wall ratio and orientations were also investigated. The other half of the research study looks into the feasibility of using the Electrochromic windows, as it is ought to be the main factor governing the market usage of Electrochromic windows and to investigate the possible ways to make it feasible. Different LCC parameters were studied to make it market feasible product. This study shows that installing this technology with most appropriate trigger range can reduce annual building energy consumption from 6-8% but still cost of the technology is 3 times the ASHRAE glass, which results in 70-90 years of payback. This study concludes that south orientation saves up to 3-5% of energy and 4-6% of cooling tons while north orientation gives negligible saving using EC glass. LCC parameters show that there is relative change in increasing the net saving for different parameters but none except 50% of the present glass cost is the possible option where significant change is observed. / Dissertation/Thesis / M.S.D. Architecture 2012