The study combined photoelectrocatalytic technology (PEC) with electrical glassfiber filter (EGF) to decompose volatile organic compounds (VOCs). External electrical voltage was applied to retard the recombination of electron-electron hole pairs and increase the surface temperature of the photocatalysts coated on the electrical glassfiber filter, which could further decompose VOCs more effectively via photoelectrocatalytic technology. Acetone was selected as the gasous pollutant for this particular study. A commercial TiO2 photocatalyst (AG-160) was coated on GFF via impregnation to decompose acetone in a batch PEC reactor. Operation parameters investigated in this study included acetone concentration (50~400 ppm), electrical voltage (0~6,500V), water content (0~20,000 ppm), reaction temperature (40¢J~80¢J).The incident UV light of 365 nm wavelength was irradiated by three 15-wat low pressure mercury lamps (£f=365 nm) placing above the batch PEC reactor. The TiO2-coated EGF was placed at the center of the batch PEC reactor. Acetone was injected into the reactor by a gasket syringe to conduct the PEC decomposition test. Acetone was analyzed quantitatively by a gas chromatography with a flame ionization detector (GC/FID). Finally, a Langmuir-Hinshelwood kinetic (L-H) model was proposed to simulate the PEC reaction rate of acetone. Experimental results showed that the size range of the self-produced nano-sized photocatalyst prepared by sol-gel was 35~50 nm. Three duplicate tests of PC and PEC degradation of acetone indicated that TiO2 was not deactivated during the PC and PCE reactions, hence TiO2 can be reused in the experiments. Results obtained from the PC and PEC degradation experiments indicated that the PEC reaction rate was higher than the PC reaction rate.The PEC reaction rate increased with applied electrical voltage, and the highest decomposition efficiency occurred at 6,500 V. Electrical field generated by the differences of electrical voltage can effectively enhance the oxidation capability of TiO2 since electron (e-) can be conducted to retard the recombination of electron and electron hole pairs. Both PC and PEC technologies could be used to decompose acetone. Among them, PEC had highter decomposition efficiency of acetone than PC up to 34%. Rsults obtained from the operation parameter tests reaveled that raising electrical voltage could enhance the decomposition efficiency of acetone only for electrical voltages above 2,000 V. However, the decomposition efficiency of acetone tended to level off as electrical voltage became higher. Zero-order reaction rate of the PEC reaction was observed for initial acetone concentration of 100~400 ppm, while the PEC reaction decreased gradually for initial acetone concentration reaction below 100 ppm. It revealed that the PEC reaction was pseudo ozero-order for initial acetone concentration of 100~400 ppm, and pseudo first-order reaction for acetone concentration below 100 ppm. Additionally, the PC reaction rate increased with temperature at 45-80¢J. However the PEC reaction rate increased with temperature at 45-60¢J, and decreased with temperature at 60-80¢J. An adsorptive competition between acetone and water molecules at the active sites over TiO2 surface caused either promotion or inhibition of TiO2 decomposition depending on moisture content . For the PC and PEC reactions, the optimum operating condition of water vapor concentration was 10,000 ppm, but inhibition occurred when the water vapor concentration increased up to 20,000 ppm. Finally, the Langmuir-Hinshelwood kinetic model was applied to investiage the influences of reaction temperature, initial concentration of acetone, and water content on the photoelectrocatalytic reaction rate of acetone. Model simulation results showed that photoelectrocatalytic reaction rate constant of acetone(kLH) and adsorptive equilibrium constant(KA) increased with electrical voltage and acetone initial concentration. This study sevealed that experimental and simulated results were in good agreement. Thus, PEC reaction rate of acetone on the surface of TiO2 can be also succesfully simulated by the L-H kinetic model.

In this study, the effects of bioprocess operation parameters on aromatic amino acid synthesis performance of Bacillus acidocaldarius were investigated. Firstly, in laboratory scale shake-bioreactors, a defined medium was designed in terms of its carbon and nitrogen sources, to achieve the highest cell concentration. Thereafter, the effects of bioprocess operation parameters, i.e., pH and temperature were investigated / and the optimum medium contained (kg m-3): fructose, 8 / (NH4)2HPO4, 5 / CaCl2, 0.2 / KH2PO4, 2 / NaH2PO4.2H2O, 7.318 / Na2HPO4, 0.0438 / Mg(CH3COO)2.4H2O, 87&times / 10-3 / 1 , MgSO4.7H2O / 2&times / 10-3, FeSO4.7H2O / 2&times / 10-3, ZnSO4.7H2O / 15 &times / 10-5, MnSO4.H2O / 2&times / 10-5, CuSO4.5H2O with pH0 =5, T=55&amp / #61616 / C, N=175 min-1. In this medium, the bacteria produced L-tryptophan at the highest concentration of 0.204 kg m-3 and L-phenylalanine at a maximum concentration of 0.0106 kg m-3 with no L-tyrosine production. Finally the fermentation and oxygen transfer characteristics of the bioprocess were investigated in 3.0 dm3 pilot scale bioreactors. The effects of oxygen transfer were investigated at four different conditions at the parameters air inlet rates of QO/VR =0.2, and 0.5 vvm, and agitation rates of N= 250, 500, 750 min-1. The effect of pH was investigated at pH=5 uncontrolled and controlled operations. The variations in cell, fructose, amino acid and organic acid concentrations with the cultivation time / and using the dynamic method, the oxygen uptake rate and the liquid phase mass transfer coefficient values throughout the growth phase of the bioprocess / the yield and maintenance coefficients were determined. The aromatic amino acids produced at the highest and the least amount and frequency were L-tryptophan and L-tyrosine, respectively. The highest L-tryptophan production, 0.32 kg m-3 in 17 hour was at 0.2 vvm and 500 min-1. Among all operations, the highest L-tryptophan was produced at the lowest oxygen transfer condition. Controlled-pH conditions produced more L-tryptophan.

In this study, the effects of bioprocess design parameters on &amp / #946 / -lactamase production were systematically investigated using wild type Bacillus species. For this purpose, the research programme was carried out in mainly four parts. Initially, potential &amp / #946 / -lactamase producers were screened and Bacillus licheniformis ATCC 25972, a constitutive &amp / #946 / -lactamase producer, was selected. Next, the effects of bioprocess medium components, i.e., carbon sources (glucose, fructose, sucrose, citric acid and glycerol), inorganic nitrogen sources ((NH4)2HPO4 and NH4Cl) and organic nitrogen sources (yeast extract, peptone and casamino acids), were investigated in agitation and heating rate controlled laboratory scale bioreactors. Thereafter, by using the designed medium, the effects of bioprocess operation parameters, i.e., pH and temperature, on &amp / #946 / - lactamase activity were investigated in order to achieve a higher &amp / #946 / -lactamase production. Among the investigated bioprocess conditions, the highest &amp / #946 / - lactamase activity was obtained as 275 U cm-3, in the medium with 10.0 kg m-3 glucose, 1.2 kg m-3 (NH4)2HPO4, 8.0 kg m-3 yeast extract and the salt solution, at pH0=6.0, T=32&deg / C, N=200 min-1, which was 7.9 fold higher than the activity obtained in the reference medium. Finally, using the optimum bioprocess parameters obtained in laboratory scale experiments, the fermentation and oxygen transfer characteristics of the bioprocess were investigated in 3.0 dm3 pilot scale bioreactor, having temperature, pH, foam and stirring rate controls, at Q0/V=0.5 vvm and N=500 min-1 oxygen transfer conditions. The variations in &amp / #946 / - lactamase activity, cell, glucose, amino acid and organic acid concentrations with the cultivation time / the oxygen uptake rate and the liquid phase mass transfer coefficient values were determined. Throughout the bioprocess, overall oxygen transfer coefficient (KLa) varied between 0.008-0.016 s-1 / oxygen uptake rate varied between 0.001-0.003 mol m-3 s-1. Furthermore, rate limiting step analysis was performed / the yield and maintenance coefficients for the bioprocess as well as the kinetic parameters for &amp / #946 / -lactamase were determined.

In this study, the effects of bioprocess parameters on glucose isomerase roduction by Bacillus thermoantarcticus (DSMZ 9572) were investigated. For his purpose, firstly, in laboratory scale shake-bioreactors, a defined medium was designed in terms of its carbon and nitrogen sources, to achieve the highest glucose isomerase activity. Optimum concentrations of medium components were determined by a statistical approach, namely Response Surface Methodology (RSM). RSM defined the relationship between the response, glucose isomerase activity and the independent variables, medium components. The highest glucose isomerase volumetric activity was obtained as 1630 U L-1 in the optimized medium containing 10.64 kg m-3 xylan, 5.66 kg m-3 yeast extract, 5.92 kg m-3 (NH4)2SO4, 0.25 kg m-3 MgSO4.7H2O, 0.001 kg m-3 FeSO4.7H2O, 0.001 kg m-3 ZnSO4.7H2O , 0.000075 kg m-3 MnSO4. H2O, and 0.00001 kg m-3 CuSO4.5H2O at conditions: pH0= 6.0, T=55&deg / C, N=200 min-1. Then by using the designed medium, pH and oxygen transfer conditions of the bioprocess were investigated in 3.0 dm3 pilot scale bioreactor. The effect of pH was analyzed at pH=6 uncontrolled and controlled operations with the following conditions: air inlet rate of Q0/VR=0.5 vvm and agitation rate of N=500 min-1. The effects of oxygen transfer parameters were examined, at pH=6 controlled condition, at an air inlet rate of Q0/VR=0.5 vvm and the agitation rates of N=300,500,750 min-1. The variations in glucose isomerase activity, cell, amino acid and organic acid concentrations with the cell cultivation time, specific cell growth rate, the oxygen uptake rate, the liquid phase coefficient by using the dynamic method, maintenance coefficient for oxygen and yield coefficients were determined. The highest glucose isomerase volumetric activity and cell concentration, 1838 U L-1 and 2.26 kg m-3 at the 24th of the cell cultivation were attained at 0.5 vvm, 500 min 1 and pH=6 uncontrolled operation.

The first aim of this study is the development of extracellular recombinant therapeutic protease streptokinase producing Bacillus sp., and the second aim is to determine fermentation characteristics for streptokinase production. In this context, the signal (pre-) DNA sequence of B.licheniformis (DSM1969) extracellular serine alkaline protease enzyme gene (subC: Acc. No. X03341) was ligated to 5&rsquo / end of the streptokinase gene (skc: Acc. No. S46536) by SOE (Gene Splicing by Overlap Extension) method through PCR. The resulting hybrid gene pre(subC)::skc was cloned into the pUC19 plasmid. Then, the hybrid gene was sub-cloned to pMK4 plasmid which is an E. coli-Bacillus shuttle vector with high copy number and high stability. Recombinant plasmid pMK4::pre(subC)::skc was finally transferred into B. subtilis (npr- apr-) and B. licheniformis 749/C (ATCC 25972) species. Streptokinase production capacities of these two recombinant Bacillus species were compared. The highest production was observed in recombinant B. lichenifomis 749/C (ATCC 25972) strain in a defined medium which was optimized in terms of carbon and nitrogen sources by a statistical approach, namely Response Surface Methodology (RSM). RSM evaluated the streptokinase concentration as the response and the medium components as the independent variables. The highest recombinant streptokinase concentration was found as 0.0237 kgm-3 at glucose and (NH4)2HPO4 concentrations of 4.530 and 4.838 kgm-3 respectively. The fermentation and oxygen transfer characteristics of the streptokinase production were investigated in a 3 dm3 pilot scale batch bioreactor (Braun CT2-2) equipped with temperature, pH, foam, air inlet and agitation rate controls having a working volume of VR=1.65 dm3 using the production medium optimized for the recombinant B. lichenifomis 749/C (ATCC 25972) strain. Streptokinase and &amp / #946 / -lactamase activities, cell, glucose and organic acid concentrations, dissolved oxygen, pH, oxygen uptake rate, overall liquid phase mass transfer coefficient for oxygen, maintenance coefficient for oxygen, specific cell growth rate and yield coefficients were determined through the bioprocess. The bioprocess of recombinant streptokinase production was performed at uncontrolled pH of these bioreactor operation conditions: air inlet rate of Q0/VR=0.5 vvm, and the agitation rate of N=400min-1. The resulting streptokinase volumetric activity reached its maximum as 1.16 PUml-1 (0.0026 g/l streptokinase) at t=20 h.

Η παρούσα διατριβή μελετά τις δυνατότητες υπολογισμού του πεδίου ροής δύο λειτουργικών παραμέτρων συμπεριλαμβανομένων του εκπεμπόμενου θορύβου και των εκπεμπόμενων ρύπων. Εξετάζεται η αλληλεπίδραση της καύσης με το ρευστο-θερμοδυναμικό πεδίο και τις χημικές αντιδράσεις. Περιγράφονται συνοπτικά οι διέπουσες εξισώσεις, οι μέθοδοι και τα μοντέλα της τυρβώδους καύσης και επισημαίνονται τα πλεονεκτήματα του μοντέλου των μεγάλων δινών (LES) το οποίο επιλέχθηκε εδώ. Αναπτύσσεται ένας εύχρηστος, από την ρευστοδυναμική υπολογιστική μεθοδολογία, πολυβηματικός μηχανισμός για δύο καύσιμα άμεσου ενδιαφέροντος το μεθάνιο και το προπάνιο. Προτείνεται, δηλαδή, ένα απλοποιημένο χημικό σχήμα για την οξείδωση των βασικών καυσίμων το οποίο περιέχει τον σχηματισμό του NΟx και της παραγωγής καπναιθάλης. Μετά από ανάλυση του ρόλου της καύσης στην ακουστική διακρίνονται οι δύο χαρακτηριστικοί τύποι: του θορύβου τυρβώδους καύσης (βόμβος – roar) και του θορύβου από τις ταλαντώσεις της καύσης (combustion oscillation). Παρουσιάζεται η κυματική εξίσωση και εισάγεται η έννοια του θερμο-ακουστικού όρου ο οποίος είναι συνάρτηση της απελευθερωμένης θερμότητας (q) στην φλόγα και εμφανίζεται ως όρος πηγής στην βασική εξίσωση. Στη συνέχεια η φλόγα εξετάζεται ως αυτόνομος πηγή αλλά και ως ενισχυτής θορύβου. Με την προσέγγιση της Προσομοίωσης των Μεγάλων Δινών (Large Eddy Simulation, LES) αναπτύχθηκε μια μεθοδολογία υπολογισμού του θορύβου που εκπέμπεται από το μέτωπο τυρβωδών φλογών διάχυσης. Στο πλαίσιο της προτεινομένης μεθοδολογίας το αποτέλεσμα ήταν η ανάπτυξη ενός τρισδιάστατου προγνωστικού υπολογιστικού κώδικα. Στην συνέχεια υπολογίζεται το αεροθερμοδυναμικό τυρβώδες πεδίο ροής μέσω τελειοποίησης κωδίκων του Εργαστηρίου Τεχνικής Θερμοδυναμικής, των κωδίκων που αναπτύχθηκαν στο πλαίσιο της παρούσης εργασίας αλλά και του εμπορικού κώδικα Fluent. Η μεθοδολογία, που αναπτύχθηκε με την παρούσα ερευνητική εργασία, πιστοποιήθηκε μέσω μιας σειράς πρωτότυπων μετρήσεων, του εκπεμπόμενου θορύβου στις συρρέουσες, εφαπτόμενες και ανυψωμένες και ανακυκλοφορούσες (χαμηλού και υψηλού λόγου καυσίμου/αέρα) φλόγες, σε πρωτότυπες πειραματικές διατάξεις του Εργαστηρίου. Συγκεκριμένα διαμορφώθηκε ένας καινοτόμος αεροδυναμικός φλογοσυγκρατητής πολλαπλών εγχύσεων που διατηρεί μια πλούσια γκάμα φλογών με ιδιαίτερα χαμηλό λόγο καυσίμου/αέρα. Επιτεύχθηκαν πειραματικές μετρήσεις, του ορμικού και θερμοκρασιακού πεδίου διαφόρων μορφών τυρβωδών φλογών, συντάχθηκαν σχετικά διαγράμματα και υπολογίσθηκαν οι αρχικές και οριακές συνθήκες των πειραμάτων. / In the present work the calculation of two parameters, the radiated noise and pollutants are studied. The interaction between combustion, the aerothermodynamical field and the chemical reactions is studied. The equations, the methods and the models of turbulent combustion are described here and the advantages of the large eddy simulation model (LES) which has been chosen for this case, are marked. A multi-step chemistry mechanism is developed for two fuels of great interest: methane and propane. A simple chemical scheme for the oxidation of basic fuels which includes the formation of NOx and soot is suggested in the present work. After analyzing the role of combustion in the acoustics two types of noise are distinguished the turbulent combustion noise and the noise from combustion oscillation. The wave equation is presented and the definition of thermo acoustic term which is a function of the heat release q in flame and it appears as a source term in the basic equation. The flame is examined as an autonomous source as well as a noise amplifier. With the approach of large eddy simulation (LES) a methodology for the noise calculation is developed which noise is from the turbulent diffusion flame front. In the place of the suggested methodology the result was the development of a 3-D computational code. The turbulent aerothermodynamical flow field is computed by codes has been developed in the laboratory of technical thermodynamic and by the commercial code (fluent). The methodology, which has been developed in the present work, has been certificated through a series of original measurements of the emitted noise in coaxial, tangential and lifted flames in original experimentallayouts.