Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas¿liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17¿-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17¿-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions. / Ministry of Higher Education in Libya and the Libyan Cultural Centre and Educational Bureau in London.

No description available.

Current methods for measuring energy flow rate in a pipe use a variety of invasive sensors, including temperature sensors, turbine flow meters, and vortex shedding devices. These systems are costly to buy and install. A new approach that uses non-invasive sensors that are easy to install and less expensive has been developed. A thermal interrogation method using heat flux and temperature measurements is used. A transient thermal model, lumped capacitance method LCM, before and during activation of an external heater provides estimates of the fluid heat transfer coefficient ℎ and fluid temperature. The major components of the system are a thin-foil thermocouple, a heat flux sensor (PHFS), and a heater. To minimize the thermal contact resistance 𝑅" between the thermocouple thickness and the pipe surface, two thermocouples, welded and parallel, were tested together in the same set-up. Values of heat transfer coefficient ℎ, thermal contact resistance 𝑅", time constant 𝜏, and the water temperature °C, were determined by using a parameter estimation code which depends on the minimum root mean square 𝑅𝑀𝑆 error between the analytical and experimental sensor temperature values. The time for processing data to get the parameter estimation values is from three to four minutes. The experiments were done over a range of flow rates (1.5 gallon/minute to 14.5 gallon/minute). A correlation between the heat transfer coefficient ℎ and the flow rate 𝑄 was done for both the parallel and the welded thermocouples. Overall, the parallel thermocouple is better than the welded thermocouple. The parallel thermocouple gives small average thermal contact resistance 𝑎𝑣𝑒𝑟𝑎𝑔𝑒 𝑅"=0.00001 (𝑚2.°C/𝑊), and consistence values of water temperature and heat transfer coefficient ℎ, with good repeatability and sensitivity. Consequently, a non-invasive energy flow rate meter or (BTU) meter can be used to estimate the flow rate and the fluid temperature in real life. / MS / Today, the measuring energy flow rate, measuring flow rate and the fluid temperature, in a pipe is crucial in many engineering fields. In addition, there has been increased use of energy flow rate meters in the renewable energy system and other applications such as solar thermal and geothermal to estimate the useful thermal energy. Some of the commercial energy flow rate meters are using an invasive sensor, has to be inside the pipe, including turbine flow meter and vortex shedding device. These systems are expensive and difficult to install. A new approach that uses non-invasive sensors, attached on the outside of the pipe, that are easy to install and less expensive has been developed by using the heat flux and temperature measurements. A parameter estimation routine was used to analyze the data which depends on the minimum root mean square 𝑅𝑀𝑆 error between the calculated and experimental temperature values. A correlation between the unknown parameter, heat transfer coefficient (ℎ), and the measured flow rate 𝑄 was done to estimate the flow rate. The results show that the new non-invasive system has good repeatability, 15.45%, high sensitivity, and it is easy to install. Consequently, a non-invasive energy flow rate meter or (BTU) meter can be used to estimate the flow rate and the fluid temperature in real life.

This work presents the development of a novel and non-invasive method that measures fluid flow rate and temperature in pipes. While current non-invasive flow meters are able to measure pipe flow rate, they cannot simultaneously measure the internal temperature of the fluid flow, which limits their widespread application. Moreover, devices that are able to determine flow temperature are primarily intrusive and require constant maintenance, which can shut down operation, resulting in downtime and economic loss. Consequently, non-invasive flow rate and temperature measurement systems are becoming increasingly attractive for a variety of operations, including for use in leak detection, energy metering, energy optimization, and oil and gas production, to name a few. In this work, a new solution method and parameter estimation scheme are developed and deployed to non-invasively determine fluid flow rate and temperature in a pipe. This new method is utilized in conjunction with a sensor-based apparatus--"namely, the Combined Heat Flux and Temperature Sensor (CHFT+), which employs simultaneous heat flux and temperature measurements for non-invasive thermal interrogation (NITI). In this work, the CHFT+ sensor embodiment is referred to as the British Thermal Unit (BTU) Meter. The fluid's flow rate and temperature are determined by estimating the fluid's convection heat transfer coefficient and the sensor-pipe thermal contact resistance. The new solution method and parameter estimation scheme were validated using both simulated and experimental data. The experimental data was validated for accuracy using a commercially available FR1118P10 Inline Flowmeter by Sotera Systems (Fort Wayne, IN) and a ThermaGate sensor by ThermaSENSE Corp. (Roanoke, VA). This study's experimental results displayed excellent agreement with values estimated from the aforementioned methods. Once tested in conjunction with the non-invasive BTU Meter, the proposed solution and parameter estimation scheme displayed an excellent level of validity and reliability in the results. Given the proposed BTU Meter's non-invasive design and experimental results, the developed solution and parameter estimation scheme shows promise for use in a variety of different residential, commercial, and industrial applications. / MS

No description available.

The objective of this research was to investigate the performance of two-phase spray cooling with HFC-134a and HFO-1234yf refrigerants using practical enhanced heat transfer surfaces. Results of the study were expected to provide a quantitative spray cooling performance comparison with working fluids representing the current and next-generation mobile air conditioning refrigerants, and demonstrate the feasibility of this approach as an alternative active cooling technology for the thermal management of high heat flux power electronics (i.e., IGBTs) in electric-drive vehicles. Potential benefits of two-phase spray cooling include achieving more efficient and reliable operation, as well as compact and lightweight system design that would lead to cost reduction. The experimental work involved testing of four different enhanced boiling surfaces in comparison to a plain reference surface, using a commercial pressure-atomizing spray nozzle at a range of liquid flow rates for each refrigerant to determine the spray cooling performance with respect to heat transfer coefficient (HTC) and critical heat flux (CHF). The heater surfaces were prepared using dual-stage electroplating, brush coating, sanding, and particle blasting, all featuring "practical" room temperature processes that do not require specialized equipment. Based on the obtained results, HFC-134a provided a better heat transfer performance through higher HTC and CHF values compared to HFO-1234yf at all tested surfaces and flow rates. While majority of the tested surfaces provided comparable HTC and modestly higher CHF values compared to the reference surface, one of the enhanced surfaces offered significant heat transfer enhancement.

La micro-oxygénation des vins, par la dispersion de bulles d’oxygène, est une pratique de plus en plus utilisée dans le domaine de l’œnologie. Cette technique n’est pas toujours convenablement maitrisée par manque de connaissances scientifiques sur les paramètres régissant le transfert de l’oxygène. La recherche s'est focalisée sur l'étude des coefficients de transfert en fonction des composés du vin (CO2, éthanol, sucrose, consommateurs d’oxygène) et des conditions opératoires (type de diffuseur, température, rapport entre hauteur et diamètre du contenant de liquide). Les résultats montrent que lors de la micro-oxygénation, le dioxyde de carbone dissous et le sucrose ont une incidence négative sur le transfert alors que la présence d’éthanol améliore le transfert. En ce qui concerne les conditions opératoires, l’augmentation de débit de gaz et l’augmentation de rapport entre la hauteur et le diamètre de la cuve de micro-oxygénation joue positivement sur le transfert d’oxygène La surface spécifique des bulles et le coefficient de transfert de matière ont pu être dissociés pour les vins. La nature tensio-active des composés du vin semble être un élément important sur le transfert de matière. Les connaissances acquises ont été appliquées à la micro-oxygénation au cours de deux étapes de l'élaboration des vins : la fermentation alcoolique avec la maitrise de l’apport d’oxygène et la simulation de la technique d’élevage en barrique par micro-oxygénation couplée à l’ajout de copeaux de bois. Une nouvelle approche concerne l'étude d'un contacteur membranaire qui permet le transfert d’oxygène par diffusion. / Micro-oxygenation of the wines, by the dispersion of oxygen bubbles, is a practice increasingly used in oenology. This technique is not always suitably controlled for lack of scientific knowledge on the parameters governing the transfer of oxygen. Research was focused on the study of transfer coefficients in function of wine components (CO2, ethanol, sucrose, consuming oxygen) and of operating conditions (type of diffuser, temperature, relationship between height and diameter of the container of liquid). The results show that during micro-oxygenation, the dissolved carbon dioxide and the sucrose have a negative incidence on the transfer whereas the presence of ethanol improves the transfer. As operating conditions are concerned, the increase in gas output and the increase in micro-oxygenation tank height/diameter ratio positively influence oxygen transfer. For wines, the specific surface of the bubbles and the mass transfer coefficient could be dissociated. The surfactant nature of wine components seems to be the most important factor in mass transfer. The knowledge so acquired was applied to micro-oxygenation during two stages of wine making: alcoholic fermentation with the oxygen yield control and the simulation of ageing technique in barrels coupled with the wood chips addition. A new approach relates to the study of a membrane contactor application allowing the oxygen transfer by diffusion.

Αντικείμενο της διατριβής είναι η υπολογιστική και πειραματική διερεύνηση των φαι-νομένων μεταφοράς θερμότητας και μάζας σε πρότυπη εργαστηριακή μονάδα μηχανικής ξήρανσης δια συναγωγής, η οποία σχεδιάσθηκε, κατασκευάσθηκε και εξοπλίσθηκε με μετρητικό εξοπλισμό και ολοκληρωμένο σύστημα ελέγχου, συλλογής και επεξεργασίας των πειραματικών μετρήσεων. Στην εργαστηριακή μονάδα ξήρανσης παρέχεται η δυνατότητα μεταβολής και ελέγχου των βασικών παραμέτρων από τις οποίες επηρεάζεται η θερμική διεργασία της ξήρανσης, όπως η ταχύτητα, η θερμοκρασία και η υγρασία του αέρα ξήρανσης. Η μέτρηση της αποβολής της περιεχομένης υγρασίας στο υπό ξήρανση προϊόν πραγματοποιείται μέσω δυναμοκυψελών υψηλής ακρίβειας, ενώ η χωρική κατανομή της ταχύτητας ροής στην είσοδο του θαλάμου ξήρανσης κατά τη διεξαγωγή κάθε κύκλου πειραμάτων συνεχώς μετρείται με συστοιχία σωλήνων pitot και ενός συστήματος συγκροτούμενου από ηλεκτροβαλβίδες και μορφομετατροπέα πίεσης. Η χωρική κατανομή της θερμοκρασίας και της ταχύτητας στον θάλαμο ξήρανσης είναι δυνατή μέσω αισθητηρίων που προσαρμόζονται σε καρτεσιανό σύστημα μετακίνησης ελεγχόμενου από υπολογιστή το οποίο σχεδιάσθηκε, κατασκευάσθηκε και τοποθετήθηκε στην έξοδο του κατακόρυφου θαλάμου ξήρανσης αποτελώντας πλέον αναπόσπαστο τμήμα της εργαστηριακής μονάδας. Όλες οι μετρήσεις πραγματοποιήθηκαν στον κατακόρυφο θάλαμο ξήρανσης, ενώ παρέχεται η δυνατότητα διεξαγωγής μετρήσεων και στο θάλαμο ξήρανσης οριζόντιας διάταξης. Στα πλαίσια της διατριβής, έγινε συστηματική πειραματική διερεύνηση της ξήρανσης δια συναγωγής σε φέτες κυδωνιών και μελετήθηκε η επίδραση διαφόρων παραμέτρων που επηρεάζουν τη θερμική διεργασία της ξήρανσης σε αυτό το αγροτικό προϊόν, για θερμοκρασίες αέρα 40, 50 και 60οC και ταχύτητες αέρα 1, 2 και 3 m/s. Σκοπός των με-τρήσεων ήταν ο προσδιορισμός: (i) της επίδρασης της θερμοκρασίας και της ταχύτητας του αέρα στις καμπύλες ξήρανσης κυλινδρικών φετών κυδωνιού, (ii) της επίδρασης του πάχους των κυλινδρικών φετών του κυδωνιού στις καμπύλες ξήρανσης, (iii) της επίδρασης του προσανατολισμού των κυλινδρικών φετών κυδωνιού, ως προς τη διεύθυνση της προσπίπτουσας ροής, στις καμπύλες ξήρανσης, (iv) της προσαρμογής των καμπύλων ξήρανσης σε διάφορα απλά μοντέλα ξήρανσης λεπτού στρώματος, v) των ενεργών συντελεστών διάχυσης υγρασίας για την κάθε περίπτωση με την μέθοδο της κλίσης (slope method) και οι οποίοι συσχετίστηκαν με τη θερμοκρασία του αέρα ξήρανσης έτσι ώστε ο συντελεστής διάχυσης της υγρασίας να εκφρασθεί με την εξίσωση μορφής τύπου Arrhenius και vi) των διεπιφανειακών συντελεστών μεταφοράς θερμότητας και μάζας οι οποίοι στη εκφράζονται ως συνάρτηση των αδιάστατων αριθμών Nu, Re και Pr με τη μορφή Nu=aRebPr1/3. Η προσομοίωση του ρευστοθερμικού πεδίου στο θάλαμο ξήρανσης και ο υπολογισμός των διεπιφανειακών συντελεστών μεταφοράς θερμότητας και μάζας γύρω από την επι-φάνειας του προϊόντος πραγματοποιήθηκε με χρήση της εργαλείων της υπολογιστικής ρευστοδυναμικής (CFD). Έγιναν προσομοιώσεις CFD μόνιμης κατάστασης (steady-state), θεωρώντας τυρβώδη ροή ενώ ο θάλαμος ξήρανσης και η κυλινδρική φέτα του κυδωνιού εξιδανικεύθηκε ως μια δισδιάστατη αξονοσυμμετρική διαμόρφωση. Ως μοντέλο τύρβης χρησιμοποιήθηκε το μοντέλο SST (Shear Stress Transport) k-ω, ενώ για την προσέγγιση του οριακού στρώματος στα τοιχώματα του προϊόντος επιλέχθηκε το μοντέλο LRNM (Low Reynolds Number Model). Από την επίλυση των πεδίων ροής και θερμοκρασίας προσδιορίσθηκαν οι κατανομές των διεπιφανειακών συντελεστών στην προσήνεμη και στην υπήνεμη πλευρά της κυλινδρικής φέτας του κυδωνιού για όλες τις πειραματικές συνθήκες. Από τον υπολογισμό του μέσων σταθμισμένων τιμών του διεπιφανειακού συντελεστή μεταφοράς θερμότητας συνάγεται μια συσχέτιση των αδιάστατων αριθμών Nu, Re και Pr, στη μορφή Nu=aRebPr1/3, που ως εύρημα εμπλουτίζει την υφιστάμενη βιβλιογραφία. Στο τελικό στάδιο της διατριβής, αναπτύχθηκε και αποτιμήθηκε σε σύγκριση με τις πειραματικές μετρήσεις ένα μονοδιάστατο αριθμητικό μοντέλο μη-μόνιμης μεταφοράς θερμότητας και μάζας για την προσομοίωση των καμπυλών ξήρανσης σε κυλινδρικές φέτες κυδωνιών. Στο μοντέλο, η μεταφορά θερμότητας εντός του προϊόντος γίνεται με αγωγή ενώ η μεταφορά μάζας γίνεται με υγρή διάχυση, με την εξάτμιση του περιεχόμενου νερού στις φέτες του κυδωνιών να λαμβάνει χώρα από την προσήνεμη και την υπήνεμη επιφάνεια. Στο αριθμητικό μοντέλο, λαμβάνεται υπόψη η συρρίκνωση της κυλινδρικής φέτας του κυδωνιού, θεωρώντας ότι ο όγκος της προϊόντος μειώνεται κάθε φορά κατά τον όγκο του νερού που εξατμίζεται τις δύο επιφάνειες της φέτας. Στον αριθμητικό κώδικα, οι θερμοφυσικές ιδιότητες του κυδωνιού και του αέρα προσδιορίζονται από σχέσεις που συναντώνται στη βιβλιογραφία, ο ενεργός συντελεστής διάχυσης της υγρασίας εισάγεται ως αποτέλεσμα της επεξεργασίας των πειραματικών μετρήσεων, ενώ για τους συντελεστές μεταφοράς χρησιμοποιήθηκαν οι μέσες σταθμισμένες τιμές των διεπιφανειακών συντελεστών μεταφοράς θερμότητας και μάζας, ως αποτέλεσμα των CFD προσομοιώσεων και για περίπτωση μη-συζυγούς προσέγγισης (non-conjugated approach). Στοχεύοντας στην καλύτερη προσαρμογή των πειραματικών μετρήσεων και των υπολογιστικών αποτελεσμάτων, χρησιμοποιήθηκε η ανάλυση μη-γραμμικής παλινδρόμησης, με τους αλγόριθμους SQP (Sequential Quadratic Programming) και εσωτερικού σημείου (internal point), για τον προσδιορισμό των συντελεστών της εξίσωσης διάχυσης της υγρασίας, με μικρή όμως βελτίωση των υπολογιστικών αποτελεσμάτων, σε συνδυασμό με τη σημαντική αύξηση του χρόνου υπολογισμού. Συμπερασματικά, από τη συνολική αξιολόγηση των αποτελεσμάτων του αριθμητικού κώδικα αποδείχθηκε ότι το προτεινόμενο αριθμητικό μοντέλο που βασίζεται στη διάχυση είναι ικανό να περιγράψει αποτελεσματικά τη σύζευξη της μεταφοράς της θερμότητας και της μάζας όπως και να αποτυπώσει ικανοποιητικά τη χρονική εξέλιξη της περιεχόμενης υγρασίας και θερμοκρασίας εντός του προϊόντος, με την ελάχιστη χρήση πειραματικών μεταβλητών εισόδου ενώ έχει ελάχιστες υπολογιστικές απαιτήσεις. Για αυτούς τους λόγους μπορεί να θεωρηθεί κατάλληλο για την ανάλυση της διαδικασίας της ξήρανσης δια συναγωγής σε οποιοδήποτε οργανικό ή μη-οργανικό προϊόν. / The objective subject of this thesis is the computational and experimental investigation of heat and mass transfer phenomena in a new laboratory mechanical convection drying unit, which was designed, constructed and equipped with measuring equipment and an integrated control system of collection and processing of experimental measurements. In laboratory drying unit there is an option to change and control the main parameters of which affected the thermal drying process, such as speed, temperature and humidity of the drying air. Measurement of the removal of moisture content in the dried product is carried out through high-precision load cells, and the spatial distribution of the flow velocity at the entrance of the drying chamber during of each experiment, is continuously measured by pitot tube array and a system composed of solenoids and a pressure transducer. The spatial distribution of temperature and velocity in the drying chamber is possible by means of sensors fitted to a computer controlled cartesian motion system which is designed, constructed and placed at the outlet of the vertical drying chamber, constituting an integral part of the facility. All measurements were performed on the vertical drying chamber while it is possible to conduct measurements in a horizontal layout of the drying chamber. In this thesis became systematic experimental investigation of convective drying sliced quince and studied the effect of various parameters affecting the thermal drying process in this agricultural product, for air temperatures of 40, 50 and 60°C and air velocities 1, 2 and 3 m/s. The purpose of the measurements was to determine: (i) the effect of temperature and air velocity in drying curves of cylindrical quince slice, (ii) the effect of the thickness of the cylindrical slice of quince in drying curves, (iii) the effect of the orientation of the cylindrical quince slice, in the direction of incident flow, in the drying curves (iv) the adjusting of the drying curves in several simple thin layer drying models v) the effective moisture diffusivity coefficients for each case with the slope method which correlated with the temperature of the drying air so that the diffusion coefficient of moisture be expressed by Arrhenius type equation form and vi ) the interfacial heat and mass transfer coefficients which expressed as a function of dimensionless numbers Nu, Re and Pr in the form Nu = aRebPr1/3. The simulation of the flow and temperature fields in the drying chamber and the calcu-lation of the interfacial heat and mass transfer coefficients around the surface of the product were performed using the tools of Computational Fluid Dynamics (CFD). CFD simulations were steady state, considering turbulent flow while drying chamber and cy-lindrical slice of quince specialized as an axisymmetric two-dimensional configuration. As turbulence model was used the SST k-ω model while on the approximation of the boundary layer near the walls of the product the LRNM was chosen. By solving the flow and temperature fields determined distributions of interfacial heat and mass transfer coefficients in front and rear of the cylindrical slice of quince for all experimental conditions. The calculation of the weighted average prices of the interfacial heat transfer coefficient indicates a correlation between dimensionless numbers Nu, Re and Pr, in the form Nu = aRebPr1/3, which as finding enriches the existing literature. In the final stage of the thesis, developed and evaluated in comparison with the experi-mental measurements, a one-dimensional transient numerical model of heat and mass transfer to simulate drying curves in cylindrical slices of quince. The heat transfer inside the quince is considered to be by conduction while the moisture transfer is considered to be governed solely by liquid diffusion. Evaporation is considered to take place only from the windward and leeward surface of the quince slice. The numerical model takes into account the shrinkage of the cylindrical slice of quince, assuming that the cylindrical volume decreases each time as much as the volume of water that evaporates on both surfaces of the slice. The numerical code used the thermophysical properties of quince and air from the literature, the effective diffusion coefficient of moisture experimentally determined by the method of the slopes, while the transfer coefficients used the weighted average prices of interfacial heat and mass transfer coefficients derived from the simulations with CFD (non-conjugated approach). In order to achieve higher accuracy between experimental data and predictions, a non-linear regression analysis, using an Arrhenius type effective diffusion equation, was also performed. However, preliminary result, obtained using the SQP (Sequential Quadratic Programming) and Interior Point algorithms for the minimization of the Chi-square function (χ2) showed only small improvement of the calculated results with a significant increase of the computational cost. In conclusion, the overall assessment of the results of the numeric code shown that the proposed numerical model based on diffusion is able to effectively describe the coupling of heat transfer and mass, as to capture the time evolution of moisture content and temperature within the product, with minimum use of experimental input variables and minimum computational requirements. For these reasons it may be considered appropriate to analyze the convective drying process in any organic or non-organic product.

Objectives set by the EU means that all buildings after 2020 has to be nearly zero energy buildings. This means that thicker layers of insulation have to be added in the wall construction which makes the wall thicker. It means that the living area will be reduced. Vacuum insulation is a highly effective type of insulation and because of its low thermal conductivity it has the ability to reduce the thickness in wall structures. This project investigates a proposal to apply vacuum insulation in one-storey buildings. In order to achieve the goals of the project, a proposal for a one-storey building was developed. Calculations have been made and the proposal was developed as an alternative to show how to construct a family home containing vacuum insulation. The empirical data was collected through interviews, document analysis and literature studies. The collected data was analyzed together with the theoretical framework that has been developed through literature studies and document analysis. Creating a wall construction containing vacuum insulation as a primary insulation usually means that the wall will be considerably thinner than a wall construction with traditional insulation. This means that living area can be saved. Vacuum insulation has to be protected properly as it is easily punctured where upon it loses the most of its insulation capacity. Vacuum insulation is not common on the Swedish construction market today, this is due to many factors, including its high price. Vacuum insulation is a good problem solver which can be used in bay windows to gain extra space. One can also make use for it in tight spaces. From an economic point of view vacuum insulation offers the greatest advantages in cities where living space is considerably higher than in rural areas. To take part of the work there is no need for prior knowledge about vacuum insulation. The project focuses only on wall structures in the single-storey villas, therefor, no indentations has been made on the floor- and roof structures or other building types. The project only focuses on newly constructed buildings. No calculations are made for moisture or production costs. / Mål uppsatta av EU innebär att samtliga byggnader som uppförs vid år 2020 måste vara nära-nollenergihus. För väggarna i konstruktionen innebär det att tjockare lager av isolering måste adderas vilket ger bredare väggkonstruktioner. Bredare väggkonstruktioner innebär även att boarean minskas. Vakuumisolering är ett högeffektivt isoleringsmaterial som genom sin låga värmeledningsförmåga har möjligheten att minska tjockleken vid väggkonstruktioner på grund av dess tunna skikt. Arbetet utreder ett förslag att applicera vakuumisolering i enplansvillor. För att uppnå arbetets mål har ett förslag på enplansvilla tagits fram. Beräkningar har gjorts och förslaget är framtaget som ett alternativ för att visa hur en villa innehållande vakuumisolering kan utformas. Det empiriska materialet har samlats in genom intervjuer, dokumentanalyser samt litteraturstudier. Empirin analyseras sedan tillsammans med det framtagna teoretiska ramverket genom litteraturstudier och dokumentanalyser. Att skapa en väggkonstruktion med vakuumisolering som primär isolering betyder oftast att väggen blir avsevärt mycket tunnare än en väggkonstruktion av traditionell isolering, vilket betyder att boarea kan sparas. Vakuumisolering måste skyddas på rätt sätt i väggkonstruktioner eftersom materialet lätt punkteras varpå det förlorar den största delen av sin isoleringsförmåga. Idag är inte vakuumisolering utbrett på den svenska byggmarknaden vilket beror på många faktorer, bland annat dess höga pris. Vakuumisolering är en väldigt bra problemlösare som med fördel kan användas i burspråk för att vinna extra utrymme. Det kan även användas i trånga utrymmen som elnischar. Ur ekonomisk synpunkt ger vakuumisolering störst fördel i städer där boarea per kvadratmeter är högre än motsvarande på landsbygden. För att ta del av arbetet krävs inga förkunskaper om vakuumisolering. Arbetet fokuserar endast på väggkonstruktioner i enplansvillor, därför har inga fördjupningar skett på golv- och takkonstruktioner eller andra byggnadstyper. Enbart nybyggnationer av trästommar är utrett. Beräkningar är inte gjorda för fukt och produktionskostnader.

<p>U okviru doktorske disertacije izvedena su eksperimentalna istraživanja osnovnih hidrodinamičkih i maseno-prenosnih karakteristika airlift reaktora sa spoljnom recirkulacijom sa ugrađenom vi&scaron;ekanalnom cevnom membranom u silaznu cev (ALSRM). ALSRM je radio na dva načina rada: bez mehurova u silaznoj cevi (način rada A) i sa mehurovima u silaznoj cevi (način rada B) u zavisnosti od nivoa tečnosti u gasnom separatoru. Ispitivani su uticaji prividne brzine gasa, povr&scaron;inskih osobina tečne faze, tipa distributora gasa i prisustva mehurova gasa u silaznoj cevi na sadržaj gasa, brzinu tečnosti u silaznoj cevi i zapreminski koeficijent prenosa mase u tečnoj fazi u ALSRM. Rezultati su poređeni sa vrednostima dobijenim u istom reaktoru ali bez membrane (ALSR). Sadržaj gasa u uzlaznoj i silaznoj cevi određivan je pomoću piezometarskih cevi merenjem hidrostatičkog pritiska na dnu i vrhu uzlazne i silazne cevi. Brzina tečnosti merena je pomoću konduktometrijskih elektroda dok je zapreminski koeficijent prenosa mase dobijen primenom dinamičke metode merenjem promene koncentracije kiseonika u vremenu optičkom elektrodom. Eksperimentalni rezultati pokazuju da sadržaj gasa, brzina tečnosti i zapreminski koeficijent prenosa mase zavise od prividne brzine gasa, vrste alkohola i tipa distributora gasa kod oba reaktora. Vi&scaron;ekanalna cevna membrana u silaznoj cevi uzrokovala je povećanje ukupnog koeficijenta trenja za 90% i time dovela do smanjenja brzine tečnosti u silaznoj cevi do 50%. Smanjena brzina tečnosti u silaznoj cevi povećala je sadržaj gasa do 16%. Predložene neuronske mreže i empirijske korelacije odlično predviđaju vrednosti za sadržaj gasa, brzinu tečnosti i zapreminski koeficijent prenosa mase.</p> / <p>An objective of this study was to investigate the hydrodynamics and the gas-liquid mass transfer coefficient of an external-loop airlift membrane reactor (ELAMR). The ELAMR was operated in two modes: without (mode A), and with bubbles in the downcomer (mode B), depending on the liquid level in the gas separator. The influence of superficial gas velocity, gas distributor&rsquo;s geometry and various diluted alcohol solutions on hydrodynamics and gas-liquid mass transfer coefficient of the ELAMR was studied. Results are commented with respect to the external loop airlift reactor of the same geometry but without membrane in the downcomer (ELAR). The gas holdup values in the riser and the downcomer were obtained by measuring the pressures at the bottom and the top of the riser and downcomer using piezometric tubes. The liquid velocity in the downcomer was determined by the tracer response method by two conductivity probes in the downcomer. The volumetric mass transfer coefficient was obtained by using the dynamic oxygenation method by dissolved oxygen probe. According to experimental results gas holdup, liquid velocity and gas-liquid mass transfer coefficient depend on superficial gas velocity, type of alcohol solution and gas distributor for both reactors. Due to the presence of the multichannel membrane in the downcomer, the overall hydrodynamic resistance increased up to 90%, the liquid velocity in the downcomer decreased up to 50%, while the gas holdup in the riser of the ELAMR increased maximally by 16%. The values of the gas holdup, the liquid velocity and the gas-liquid mass transfer coefficient predicted by the application of empirical power law correlations and feed forward back propagation neural network (ANN) are in very good agreement with experimental values.</p>