Σε έναν μεγάλο αριθμό βιομηχανικών διεργασιών απαιτείται η διαδικασία της μίξης δύο ή περισσοτέρων υλικών για την παρασκευή του τελικού προιόντος.Ο πιο συνηθισμένος τρόπος μίξης είναι η ανάδευση ενός ή περισσοτέρων υλικών σε μια δεξαμενή. Η δεξαμενή καθώς και ο υπόλοιπος απαραίτητος εξοπλισμός όπως το στροφείο που πραγματοποιεί την ανάδευση, πρέπει να είναι με τέτοιο τρόπο σχεδιασμένος ώστε να είναι σε θέση αφ’ενός να φέρει εις πέρας την διαδικασία της μίξης και την παραγωγή του τελικού αποτελέσματος, τηρώντας κάποιες προδιαγραφές, αφ’εταίρου να είναι μηχανικά ευσταθής και ασφαλής. Λόγω διαφόρων αναγκών κατά την παραγωγική διαδικασία είναι απαραίτητη η αντικατάσταση των σωληνώσεων για την μεταφορά ενός υγρού από μια δεξαμενή επεξεργασίας ή αποθήκευσης σε άλλη, με την χρησιμοποίηση συστημάτων μεταφοράς της δεξαμενής. Άλλοι λόγοι επιβάλλουν την ταυτόχρονη μεταφορά και ανάδευση υλικών σε μια δεξαμενή, ή η δεξαμενή ανάδευσης να είναι στερεωμένη σε μεταλλικά ικριώματα ή να είναι στερεωμένη πάνω σε μεταλλικούς δοκούς. Έτσι, στην περίπτωση του συστήματος μεταφοράς μιας δεξαμενής από ένα σημείο σε κάποιο άλλο πρέπει κανείς να εξετάσει τις διαταραχές που υφίσταται το υγρό που περιέχει η δεξαμενή για παράδειγμα, εξαιτίας της κίνησης της δεξαμενής, για την αποφυγή υπερχείλισης του υγρού. Επιπλέον στην περίπτωση όπου τα υλικά που περιέχει μια δεξαμενή αναδεύονται κατά την μεταφορά της ή αυτή είναι στερεωμένη σε μεταλλικά ικριώματα, πρέπει να εξετάσει κανείς τις επιδράσεις της ανάδευσης στην σταθερότητα της δεξαμενής, και συνεπώς και στο σύστημα στήριξης ή μεταφοράς της ώστε να παρέχεται η αξιοπιστία και η ασφάλεια του συστήματος. Στην παρούσα εργασία χρησιμοποιήθηκε μια δεξαμενή ανάδευσης που περιείχε νερό, και μελετήσαμε τις επιδράσεις που είχε η ανάδευση του νερού, στην ισορροπία της δεξαμενής, καταγράφοντας την κατανομή του βάρους της. Στο πρώτο κεφάλαιο δίνονται διάφοροι ορισμοί και εξισώσεις που περιγράφουν ένα ρευστό και την κίνησή του. Στο δεύτερο κεφάλαιο περιγράφονται οι μονάδες που απαρτίζουν ένα σύστημα ανάδευσης, και στο τρίτο τα αποτελέσματα των φορτίσεων της δεξαμενής κατά την ανάδευσή της, στην πειραματική διάταξη που πραγματοποιήθηκε. / In a large number of industrial processes the mixing of two or more materials is necessary for the production of a final product. The most common form of mixing is the stirring of one or more materials in a mixing tank. The tank as well as the rest of the necessary equipment, for example the impeller which is responsible for the stirring process, must be designed in such a way that it is able to successfully complete the mixing process and produce the final product, according to certain specifications, while keeping mechanical stability and safety. Different needs may arise during the production of a final product. One of these may be the need to replace the pipes which are responsible for transferring one liquid material placed in a tank to another tank, with the use of a transferring system for the tank. Another need may be the simultaneous transfer and stirring of materials in a tank or the stirring tank may need to be stabilized on metal beams. In all these cases, one must evaluate the disturbances and the vibrations which effect the liquid and the tank, in order to ensure the efficiency, stability and safety of the mixing and transfer systems. In the present experimental thesis paper, a stirring tank was used that contained water, and the effects of the stirring of the water on the stability of the tank were studied and analyzed, through the recording of the distribution of the weight during the mixing. The first chapter contains definitions and equations that describe the motion of a fluid. The next chapter describes the parts that comprise a stirring system. Lastly, the third chapter contains the results, the analysis, and the conclusions of the experimental process.

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As part of a global drive to produce renewable electricity, devices are being designed to harness energy from the waves and tidal currents. Physical scale model testing is an important part of the development process for this and other technologies. The FloWave Ocean Energy Research Facility at The University of Edinburgh is designed to conduct these tests. Here it is possible to produce multi-directional waves combined with currents in the circular tank, re-creating the complexity of the ocean. The research was driven by commercial requirements of the facility, aiming to highlight what can be learnt from testing at scale with complex conditions in a controlled environment. To enable this, it was first necessary to extend the characterisation of this new facility. Wave generation and reflections were assessed in a previous project. In this work, flow measurements taken throughout the test volume of the tank, allowed spatial and temporal variations in the currents to be determined. Waves and currents interact in a complex manner, compounded by the method of reproducing them in a tank. The influence of currents on waves in the basin was assessed. This included cases with an oblique angle between them, on which little has been published. The other part of the project addressed issues to be considered when testing in a combined wave-current basin such as FloWave. • At many sites of interest for offshore renewable energy, waves are influenced by water depth. Implications of not scaling depth consistently were considered, and design diagrams produced to facilitate understanding and quantification of potential errors. • At FloWave, waves are generated in still water around the outside of the tank. A process was therefore developed and verified to produce the desired combined conditions in the central test area following their interaction with the current. • There is a wealth of published guidance on tank testing, for ships, offshore structures, and more recently renewable energy. This has been reviewed and suggestions offered to augment this by including testing in the more advanced conditions possible in a facility like FloWave. • Tools and guidance have been developed to highlight many of the issues to be considered by clients prior to testing at FloWave. This aims to facilitate planning of a test programme by highlighting potential knowledge gaps and recording decisions made. Flowcharts have been produced to represent this graphically, with a corresponding checklist of questions for clients, which have been trialled in a pilot study. Outputs from this research are being used to help deliver both academic and commercial client tests at FloWave. The test area in currents was shown to be > 50m2 with < 10% variation in flow, and the combined wave-current conditions possible have been explored. Results that are important when designing client test plans.

As a young child, my father once told me that it is impossible to know and understand everything. At first I did not believe him, but as I grew up, I realised why he said it. This realisation did not, however, dawn on me overnight. During my training many textbooks and lecturers painted the picture of a world that can be described by a few simple laws. When I finished my training and started to work as a water engineer, I realised that this was only an illusion. The difference between theory and practise was bigger than I thought. I eventually came to the realisation, through the wisdom of many others, that this gap between theory and reality is not only due to the limitations of science and technology, but also to beliefs. Often these beliefs are so intertwined with science and technology that the scientists and technologists themselves are not aware of it. This study attempts to explain why differences between theory and practise exist. The modelling of water treatment process tanks is used as a vehicle to demonstrate this. In the process it is shown that scientists and technologists cannot use models in a responsible manner without also considering the broader philosophical aspects. My personal most satisfying contribution was to demonstrate the influence of philosophical views on process tank design methods. The study also makes original contributions in the field of water treatment process tank modelling. Computational Fluid Dynamic models are used in an attempt to understand water treatment process tanks better. This modelling technique applies a combination of scientific, technological and modelling concepts. An appropriate question by many technical readers will be why a significant portion of this text includes philosophical concepts if the title of the study deals with process tank modelling? First the arguments presented and the process of argumentation, can assist many scientists and engineers to develop a much broader view of science, technology and models. A second reason for this inclusion is the background it gives to where theories originated and how they were developed. Most importantly, however, the realisation of the inherent shortcomings of theories came much later and this is the third reason for its inclusion. It deals with exposing invalid assumptions and misconceptions that are held in the design of some process tanks. These misconceptions often originate from a philosophical view rather than a scientific observation. The fourth reason is to demonstrate the importance of normative aspects in the practise of science and technology. Finally, it can also benefit philosophers in the sense that they can see how philosophy can be applied to very practical problems. A need that is unsatisfied in many scientific and technical fields. / Prof. J. Haarhoff

This diploma thesis deals with analysis of particular elements of ground water storage tanks, their comparison and describtion of their characteristic. Basic information of designing volume of accumulation tank is included in the first part followed by a key section where particular construction parts and elements are described. In the next section, new types of water tanks are mentioned. In the final section of this thesis, study of 5 existing water tanks was accomplished. A technical recommendation is summed up in the final part that can be taken into account when constructing a new water storage tank.

Interest and research on herbicide-resistant cropping systems has increased dramatically since the introduction of glyphosate-resistant crops in 1996. New advances in herbicide-resistant cropping systems, such as dicambaresistant soybean and cotton, provide opportunities to help alleviate selection pressure currently applied by glyphosate-only systems. While there is no doubt dicamba-resistant genetics will have a huge impact on production practice, there are questions that must be answered about possible interactions with dicamba and glyphosate tank mixtures. The primary objectives of this research were to evaluate the effect of glyphosate/dicamba combinations on common Mississippi weed species, as well as determine effects of these combinations on absorption and translocation of dicamba. Four monocots: johnsongrass, barnyardgrass, large crabgrass, and broadleaf signalgrass; and four dicots: sicklepod, hemp sesbania, prickly sida, and pitted morningglory, were chosen to represent troublesome weed species. Plants were sprayed at the 4±1 leaf stage with glyphosate, dicamba, and combinations of the two herbicides. Rates were chosen with the goal of achieving 40 to 70% control in order to determine synergistic/antagonistic responses. Antagonism was observed in each species tested. Increasing rates of both herbicides alleviated the antagonism in most weeds. A synergistic response was observed in all graminaceous species and pitted morningglory when herbicide rates increased. Barnyardgrass and sicklepod were selected to quantify absorption and translocation of 14C-dicamba in order to account for interactions observed from tank-mix combinations. Rates for dicamba and glyphosate were selected based on results from the interaction study. Dicamba, glyphosate, and tank-mix combinations were applied to sicklepod and barnyardgrass before treatment with 14C-dicamba. Plants were harvested 4, 12, 24, and 72 h after treatment. The addition of glyphosate to dicamba resulted in reduced translocation of 14C-dicamba in both species. While the data did indicate a translocation interaction, glyphosate and dicamba combinations effectively overcame antagonism effects when higher rates were applied on sicklepod and barnyardgrass.

Approved for public release; distribution is unlimited / This thesis presents the design test and evaluation of a fiber optic remote monitoring system. Practical aspects of loss measurement, link analysis, receiver design, and controller implementation are examined. The fundamental operation of the system relies on conversion of the voltage data to be a variable frequency TTL pulse train. The pulse train modulates a 1300 nm laser, which transmits the telemetry data via single mode fiber to the shore station. One of the two test voltages can be selected by the shore-based controller, via the bidirectional link. Laboratory test results are included / This thesis presents the design, test and evaluation of a fiber optic remote monitoring system. Practical aspects of loss measurement, link analysis, receiver design, and controller implementation are examined. The fundamental operation of the system relies on conversion of the voltage data to a variable frequency TTL pulse train. The pulse train modulates a 1300 nm laser, which transmits the telemetry data via single mode fiber to the shore station. One of two test voltages can be selected by the shore-based controller, via the bidirectional link. Laboratory test results are included. / http://archive.org/details/longhaulunderwat00dena / United States Navy / Lieutenant Commander, United States Navy

The hydrodynamics of an agitated tank have been studied byphase-Doppler anemometry. The focus is on the impeller anddischarge region of a 45o pitched blade turbine (PBT). Thestudy includes agitation of pure water as well as of a dilutesuspension of process particles. A three-dimensionalphase-Doppler anemometer is used to measure local,instantaneous, three-dimensional velocities of the fluid and ofthe suspended particles. A shaft encoding technique is used toresolve the turbulent fluctuations from the periodic velocityfluctuation due to the impeller blades, and to provide moredetailed information about the variations relative to theimpeller blade. Velocity bias is corrected for by the total3-dimensional velocity. The mean flow field, the fluctuating velocities, and thecomplete Reynolds stress tensor, are reported for the liquidphase flow. The periodic fluctuations in the flow that aregenerated by the impeller blades are eliminated in theexamination of the turbulence. The anisotropy of the turbulenceis assessed by the invariants of the anisotropy tensor. Thetrailing vortex structure is demonstrated to be associated withhigh kinetic energy and strong anisotropy of the turbulence.The vortex is still observable 130-140 degrees behind theblade. It gradually moves down from the impeller blade but thelocation in radial direction remains essentially unchanged. Theinfluence of the periodic fluctuations is examined and it isshown that the turbulence appears more isotropic when theperiodic fluctuations are not eliminated. The solid particle concentration is low below the impellerand is high above the impeller tip. The particles diverge fromthe liquid flow mean direction, especially below the agitatorclose to the tip where the strongest turbulence is found.Periodic fluctuations in the particle concentration relate tothe variations found in the angle-resolved mean velocity andfluctuating velocity. The ratio of the maximum to the minimumconcentration is about 2.0 in the present study. The baffles influence on the conditions in the impellerregion, and this influence can be observed on the fluid meanvelocity field, the angle-resolved velocities, the kineticenergy, and on the behavior of larger process particles. In theimpeller region the highest kinetic energies are about 15%higher upstream of the baffle than at the middle plane betweenthe baffles. The highest energy level in the middle plane isactually the lowest value and is therefore not representativewhen rotation symmetry is assumed. Local energy dissipation rates have been investigated, andthe integration of the local energy dissipation rates overdifferent control volumes has been compared with macroscopicenergy balance calculations. The discrepancy is significant.Different reasons have been analyzed and recommendations forfurther investigation are given. I n the outflow region there is a significant variation alsoin the direction of the instantaneous velocity, which may leadto direction bias in the case of non-spherical measurementvolume. In order to account for this direction bias, amathematical model is developed to estimate the projected areaof the measurement volume in LDA or PDA. It is shown that theprojected area variation can lead to a significant directionbias in determination of time averaged values and localparticle concentration in a highly turbulent stirred tank flow.This bias is however negligible for an orthogonal optical setup, as is used in the present study. <b>Keywords:</b>Hydrodynamics, phase-Doppler anemometer,suspension, pitched-blade turbine, anisotropy, turbulence,Reynolds stresses, trailing vortex, kinetic energy, stirredtank

The main aim of this thesis is to implement a voltage-controlled oscillator for a Galileo/GPS receiver with a center frequency of 1.5 GHz in 150 nm CMOS process. As the designed VCO has to be integrated in a phase locked loop, VCO gain is selected high enough for the PLL to lock even with process variations. A new state of art architecture called double harmonic tuned VCO is selected and designed for this GPS application. It uses a complex combination of inductors and capacitors to reduce phase-noise of the VCO by suppressing second harmonic oscillations in the tail node of VCO. The designed VCO shows significant improvement in phase-noise performance compared to a normal LC tank VCO by reducing phase-noise around 4 dBc/Hz. The VCO has a phase-noise of -128 dBc/Hz at 1 MHz offset from center frequency with a power consumption of 5 mW and a tuning range of about 257 MHz for a 1 V tuning voltage range.