In this thesis we propose, analyze, and investigate numerically a novel two-level Galerkin reduced order model (2L-ROM) for the efficient and accurate numerical simulation of the steady Navier-Stokes equations. In the first step of the 2L-ROM, a relatively low-dimensional nonlinear system is solved. In the second step, the Navier-Stokes equations are linearized around the solution found in the first step, and a higher-dimensional system for the linearized problem is solved. We prove an error bound for the new 2L-ROM and compare it to the standard Galerkin ROM, or one-level ROM (1L-ROM), in the numerical simulation of the steady Burgers equation. The 2L-ROM significantly decreases (by a factor of 2 and even 3) the 1L-ROM computational cost, without compromising its numerical accuracy. / Master of Science / In this thesis we introduce a new method for efficiently and accurately simulating fluid flow, the Navier-Stokes equations, called the two-level Galerkin reduced order model (2L-ROM). The 2L-ROM involves solving a relatively low-dimensional nonlinear system in the first step, followed by a higher-dimensional linearized system in the second step. We show that this method produces highly accurate results while significantly reducing computational costs compared to previous methods. We provide a comparison between the 2L-ROM and the standard Galerkin ROM, or one-level ROM (1L-ROM), by modeling the steady Burgers equation, as an example. Our results demonstrate that the 2L-ROM reduces the computational cost of the 1L-ROM by a factor of 2 to 3 without sacrificing accuracy.

Dynamical systems are useful tools for modeling many complex physical phenomena. In many situations, we do not have access to the governing equations to create these models. Instead, we have access to data in the form of input-output measurements. Data-driven approaches use these measurements to construct reduced order models (ROMs), a small scale model that well approximates the true system, directly from input/output data. Frequency domain data-driven methods, which require access to values (and in some cases to derivatives) of the transfer function, have been very successful in constructing high-fidelity ROMs from data. However, at times this frequency domain data can be difficult to obtain or one might have only access to time-domain data. Recently, Burohman et al. [2020] introduced a framework to approximate transfer function values using only time-domain data. We first discuss improvements to this method to allow a more efficient and more robust numerical implementation. Then, we develop an algorithm that performs optimal-H2 approximation using purely time-domain data; thus significantly extending the applicability of H2-optimal approximation without a need for frequency domain sampling. We also investigate how well other established frequency-based ROM techniques (such as the Loewner Framework, Adaptive Anderson-Antoulas Algorithm, and Vector Fitting) perform on this identified data, and compare them to the optimal-H2 model. / Master of Science / Dynamical systems are useful tools for modeling many phenomena found in physics, chemistry, biology, and other fields of science. A dynamical system is a system of ordinary differential equations (ODEs), together with a state to output mapping. These typically result from a spatial discretization of a partial differential equation (PDE). For every dynamical system, there is a corresponding transfer function in the frequency domain that directly links an input to the system with its corresponding output. For some phenomena where the underlying system does not have a known governing PDE, we are forced to use observations of system input-output behavior to construct models of the system. Such models are called data-driven models. If in addition, we seek a model that can well approximate the true system while keeping the number of degrees of freedom low (e.g., for fast simulation of the system or lightweight memory requirements), we refer to the resulting model as a reduced order model (ROM). There are well established ROM methods that assume access to transfer function input-output data, but such data may be costly or impossible to obtain. This thesis expands upon a method introduced by Burohman et al. [2020] to infer values and derivatives of the transfer function using time domain input-output data. The first contribution of this thesis is to provide a robust and efficient implementation for the data informativity framework. We then provide an algorithm for constructing a ROM that is optimal in a frequency domain sense from time domain data. Finally, we investigate how other established frequency domain ROM techniques perform on the learned frequency domain data.

In orbit, finding the "bottom" of your coffee cup is a non-trivial task. Subtle forces often masked by gravity influence the containment and transport of fluids aboard spacecraft, often in surprising non-intuitive ways. Terrestrial experience with capillary forces is typically relegated to the micro-scale, but engineering community exposure to large length scale capillary fluidics critical to spacecraft fluid management design is low indeed. Low-cost drop towers and fast-to-flight International Space Station (ISS) experiments are increasing designer exposure to this fresh field of study. This work first provides a wide variety of drop tower tests that demonstrate fundamental and applied capillary fluidics phenomena related to liquid droplets and gas bubbles. New observations in droplet auto-ejection, droplet combustion, forced jet combustion, puddle jumping, bubble jumping, and passive phase separation are presented. We also present the Capillary Beverage Experiment on ISS as a fun and enlightening application of capillary fluidics where containment and passive control of poorly wetting aqueous capillary systems is observed. Astronauts are able to smell their coffee from the open stable container while still drinking in an Earth-like manner with the role of gravity replaced by the combined effects of surface tension, wetting, and special container geometry. The design, manufacture, low-g demonstrations, and quantitative performance of the Space Cups are highlighted. Comparisons of numerical simulations, drop tower experiments, and ISS experiments testify to the prospects of new no-moving-parts capillary solutions for certain water-based life support operations aboard spacecraft.

No description available.

Erkenntnisse aus paläoklimatologischen Studien, theoretischen Betrachtungen und Modellsimulationen deuten darauf hin, dass anthropogene Emissionen von Treibhausgasen und Aerosolen zu großskaligen, singulären Klimaereignissen führen könnten. Diese bezeichnen stark nichtlineare, abrupte Klimaänderungen, mit regionalen bis hin zu globalen Auswirkungen. Ziel dieser Arbeit ist die Entwicklung von Modellen zweier maßgeblicher Komponenten des Klimasystems, die singuläres Verhalten aufweisen könnten: die atlantische thermohaline Zirkulation (THC) und der indische Monsun. Diese Modelle sind so konzipiert, dass sie den Anforderungen der "Integrated Assessment"-Modellierung genügen, d.h., sie sind realistisch, recheneffizient, transparent und flexibel. <br /> <br /> Das THC-Modell ist ein einfaches, interhemisphärisches Boxmodell, das anhand von Daten kalibriert wird, die mit einem gekoppelten Klimamodell mittlerer Komplexität erzeugt wurden. Das Modell wird durch die globale Mitteltemperatur angetrieben, die mit Hilfe eines linearen Downscaling-Verfahrens in regionale Wärme- und Süßwasserflüsse übersetzt wird. Die Ergebnisse einer Vielzahl von zeitabhängigen Simulationen zeigen, dass das Modell in der Lage ist, maßgebliche Eigenschaften des Verhaltens komplexer Klimamodelle wiederzugeben, wie die Sensitivität bezüglich des Ausmaßes, der regionalen Verteilung und der Rate der Klimaänderung. <br /> <br /> Der indische Monsun wird anhand eines neuartigen eindimensionalen Boxmodells der tropischen Atmosphäre beschrieben. Dieses enthält Parmetrisierungen der Oberflächen- und Strahlungsflüsse, des hydrologischen Kreislaufs und derHydrologie der Landoberfläche. Trotz des hohen Idealisierungsgrades ist das Modell in der Lage, relevante Aspekte der beobachteten Monsundynamik, wie z.B. den Jahresgang des Niederschlags und das Eintritts- sowie Rückzugsdatum des Sommermonsuns, zufrieden stellend zu simulieren. Außerdem erfasst das Modell die Sensitivitätdes Monsuns bezüglich Änderungen der Treibhausgas- und Aerosolkonzentrationen, die aus komplexeren Modellen bekannt sind. <br /> <br /> Eine vereinfachte Version des Monsunmodells wird für die Untersuchung des qualitativen Systemverhaltens in Abhängigkeit von Änderungen der Randbedingungen eingesetzt. Das bemerkenswerteste Ergebnis ist das Auftreten einer Sattelknotenbifurkation des Sommermonsuns für kritische Werte der Albedo oder der Sonneneinstrahlung. Darüber hinaus weist das Modell zwei stabile Zustände auf: neben dem niederschlagsreichen Sommermonsun besteht ein Zustand, der sich durch einen schwachen hydrologischen Kreislauf auszeichnet. Das Beachtliche an diesen Ergebnissen ist, dass anthropogene Störungen der plantetaren Albedo, wie Schwefelemissionen und/oder Landnutzungsänderungen, zu einer Destabilisierung des indischen Monsuns führen könnten. <br /> <br /> Das THC-Boxmodell findet exemplarische Anwendung in einem "Integrated Assessment" von Klimaschutzstrategien. Basierend auf dem konzeptionellen und methodischen Gerüst des Leitplankenansatzes werden Emissionskorridore (d.h. zulässige Spannen an CO2-Emissionen) berechnet, die das Risiko eines THC-Zusammenbruchs begrenzen sowie sozioökonomische Randbedingungen berücksichtigen. Die Ergebnisse zeigen u.a. eine starke Abhängigkeit der Breite der Emissionskorridore von der Klima- und hydrologischen Sensitivität. Für kleine Werte einer oder beider Sensitivitäten liegt der obere Korridorrand bei weit höheren Emissionswerten als jene, die von plausiblen Emissionsszenarien für das 21. Jahrhundert erreicht werden. Für große Werte der Sensitivitäten hingegen, verlassen schon niedrige Emissionsszenarien den Korridor in den frühen Jahrzehnten des 21. Jahrhunderts. Dies impliziert eine Abkehr von den gegenwärtigen Emissionstrends innherhalb der kommenden Jahrzehnte, wenn das Risko eines THC Zusammenbruchs gering gehalten werden soll. <br /> <br /> Anhand einer Vielzahl von Anwendungen - von Sensitivitäts- über Bifurkationsanalysen hin zu integrierter Modellierung - zeigt diese Arbeit den Wert reduzierter Modelle auf. Die Ergebnisse und die daraus zu ziehenden Schlussfolgerungen liefern einen wertvollen Beitrag zu der wissenschaftlichen und politischen Diskussion bezüglich der Folgen des anthropogenen Klimawandels und der langfristigen Klimaschutzziele. / Concerns have been raised that anthropogenic climate change could lead to large-scale singular climate events, i.e., abrupt nonlinear climate changes with repercussions on regional to global scales. One central goal of this thesis is the development of models of two representative components of the climate system that could exhibit singular behavior: the Atlantic thermohaline circulation (THC) and the Indian monsoon. These models are conceived so as to fulfill the main requirements of integrated assessment modeling, i.e., reliability, computational efficiency, transparency and flexibility. <br /> <br /> The model of the THC is an interhemispheric four-box model calibrated against data generated with a coupled climate model of intermediate complexity. It is designed to be driven by global mean temperature change which is translated into regional fluxes of heat and freshwater through a linear down-scaling procedure. Results of a large number of transient climate change simulations indicate that the reduced-form THC model is able to emulate key features of the behavior of comprehensive climate models such as the sensitivity of the THC to the amount, regional distribution and rate of change in the heat and freshwater fluxes. <br /> <br /> The Indian monsoon is described by a novel one-dimensional box model of the tropical atmosphere. It includes representations of the radiative and surface fluxes, the hydrological cycle and surface hydrology. Despite its high degree of idealization, the model satisfactorily captures relevant aspects of the observed monsoon dynamics, such as the annual course of precipitation and the onset and withdrawal of the summer monsoon. Also, the model exhibits the sensitivity to changes in greenhouse gas and sulfate aerosol concentrations that are known from comprehensive models. <br /> <br /> A simplified version of the monsoon model is employed for the identification of changes in the qualitative system behavior against changes in boundary conditions. The most notable result is that under summer conditions a saddle-node bifurcation occurs at critical values of the planetary albedo or insolation. Furthermore, the system exhibits two stable equilibria: besides the wet summer monsoon, a stable state exists which is characterized by a weak hydrological cycle. These results are remarkable insofar, as they indicate that anthropogenic perturbations of the planetary albedo such as sulfur emissions and/or land-use changes could destabilize the Indian summer monsoon. <br /> <br /> The reduced-form THC model is employed in an exemplary integrated assessment application. Drawing on the conceptual and methodological framework of the tolerable windows approach, emissions corridors (i.e., admissible ranges of CO2- emissions) are derived that limit the risk of a THC collapse while considering expectations about the socio-economically acceptable pace of emissions reductions. Results indicate, for example, a large dependency of the width of the emissions corridor on climate and hydrological sensitivity: for low values of climate and/or hydrological sensitivity, the corridor boundaries are far from being transgressed by any plausible emissions scenario for the 21st century. In contrast, for high values of both quantities low non-intervention scenarios leave the corridor already in the early decades of the 21st century. This implies that if the risk of a THC collapse is to be kept low, business-as-usual paths would need to be abandoned within the next two decades. <br /> <br /> All in all, this thesis highlights the value of reduced-form modeling by presenting a number of applications of this class of models, ranging from sensitivity and bifurcation analysis to integrated assessment. The results achieved and conclusions drawn provide a useful contribution to the scientific and policy debate about the consequences of anthropogenic climate change and the long-term goals of climate protection. <br><br>--- <br> Anmerkung:<br> Die Autorin ist Trägerin des von der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam vergebenen Michelson-Preises für die beste Promotion des Jahres 2003/2004.

Šiuo metu Lietuvoje gana aktualus lengvatinių PVM tarifų taikymo klausimas. Lengvatinių PVM tarifų poveikis prekių/paslaugų kainai, jų paklausai, naujų darbo vietų kūrimui, valstybės pajamoms – aktuali tema ne tik Lietuvoje, bet ir visoje Europos Sąjungoje. Tai įrodo vis gausėjantys ekonomistų straipsniai mokslo leidiniuose, įvairių institucijų atliekamos PVM lengvatų poveikio analizės. Be to, lengvatinio PVM tarifo taikymo tikslingumas – dažnas visuomenės diskusijų ir žiniasklaidos susidomėjimo objektas. Darbo tikslas – išanalizuoti ir įvertinti lengvatinių pridėtinės vertės mokesčio tarifų taikymo tikslingumą, atliekant analizę. Darbo objektas – lengvatinių pridėtinės vertės mokesčio tarifų taikymas Lietuvoje ir Europos Sąjungoje bei jų poveikis ekonomikai. Darbo tikslui pasiekti buvo iškelti tokie uždaviniai: apibūdinti pridėtinės vertės mokestį, nustatant jo vietą mokesčių sistemoje ir aptariant jo reikšmingumą šalies biudžetui; išanalizuoti pagrindinius teisės aktus, reglamentuojančius pridėtinės vertės mokesčio taikymą Lietuvoje ir Europos Sąjungoje, bei išanalizuoti lengvatinių pridėtinės vertės mokesčio tarifų taikymo reglamentavimą Europos Sąjungoje ir Lietuvoje; išanalizuoti lengvatinių pridėtinės vertės mokesčio tarifų kaitą Lietuvoje; palyginti Lietuvoje ir kitose Europos Sąjungos valstybėse narėse taikomų lengvatinių pridėtinės vertės mokesčio tarifų dydžius ir jais apmokestinamų prekių/paslaugų grupes; palyginti pardavimų, apmokestinamų lengvatiniais... [toliau žr. visą tekstą] / The effect of the value added tax decrease (VAT) on prices, inquiry, employment and public revenue is subjected regularly to the intensive debate not only in Lithuania, but also in the whole European Union (EU). The importance of reduced VAT effect shows growing number of economic articles, also the application of the reduced VAT is a frequent discussion object in the society and in the media. The goal of the work is to analyze the importance of the application of the reduced VAT sentences. The object of the work is the economic effects of the application of the reduced VAT sentences in Lithuania and in the European Union. To reach a purpose of the work, such tasks are issued: To define VAT and to explain its importance; to analyze the most important VAT laws; to analyze the alternation of the reduced VAT sentences in Lithuania; to compare the reduced VAT sentences in Lithuania and in the EU; to compare the categories of goods and services which are taxed on the VAT sentence in the EU; to compare the interest of the base of the reduced price in the EU; to explain the purposes of the VAT decrease; to analyze the price effects, production effects and occupation effects of VAT decrease; to overlook views of different institutions. In the work such working methods are applied: Analysis of the juridical documents and the nonfiction literature; contents analysis; analysis of the statistical information; Comparative analysis and a review of the electronic data base. Work hypothesis... [to full text]

No description available.

Made available in DSpace on 2016-03-15T19:36:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-18 / Fundo Mackenzie de Pesquisa / A two-dimensional structure with a thickness of one atom in a Bravais lattice in a "honeycomb". So it is known graphene, with interesting property both in basal plane as the edges of the material. Consisting of carbon atoms in its sp2 hybridization, graphene has applications to mechanical areas, electrical, optical, chemistry, biology. This requires mastered the techniques of obtaining graphene. This paper presents the study of obtaining exfoliated material, seeking to control the process as well as obtain graphene by electrochemical. The process of obtaining exfoliation is important because through it can obtain more control over the exfoliated material. The material obtained was analyzed by Raman spectroscopy. Our results show that it is possible to obtain exfoliated material, and as the spectra material by analyzing the intensity of the peaks. / Uma estrutura bidimensional com a espessura de um átomo, em uma rede de bravais em forma de favos de mel . Assim é conhecido o grafeno, com propriedade interessante tanto no plano basal como nas bordas do material. Constituído de átomos de carbono em sua hibridização sp2, o grafeno possui aplicações às áreas de mecânica, elétrica, ótica, química, biologia. Para isso é necessário dominar as técnicas de obtenção de grafeno. Este trabalho apresenta o estudo da obtenção de material esfoliado, buscando controle no processo, além de se obter grafeno por via eletroquímica. O processo de obtenção por esfoliação eletroquímica é importante, pois por meio dele pode-se adquirir mais controle sobre o material esfoliado. O material obtido foi analisado através da técnica de Espectroscopia Raman. Os resultados mostraram que é possível obter material esfoliado e a análise deste material através da intensidade das bandas de seu espectro Raman.

Graphene sheets, one atom thick, two dimensional layers of carbon atoms, have gained enormous importance over the past few years due to their unique attributes - high electronic, thermal conductivities and exceptional mechanical strength. Chemical reduction of graphene oxide (GO) has been considered as a viable route for large scale production of graphene sheets. The reduced graphene oxide (r -GO) sheets although their conductivities are comparatively lower than that of graphene are nevertheless versatile material for applications in thin films and composites. An important consideration in the design of solution processing techniques for the preparation of processable graphene sheets is the dispersibility of GO and r -GO in different solvents, especially aqueous dispersibility. While GO is dispersible in water over a wide range of pH values, r -GO shows poor dispersibility and over a limited range of pH values. Graphene oxide, the oxidized form of graphene, are single atomic layers with lateral dimension that can extend to hundreds of nanometers. The sheets contain a sizable fraction of carbons that are sp3 hybridized and covalently bonded to oxygen in the form of epoxy, carbonyls as well as ionizable hydroxyl and carboxylic functional groups located on the rim of the sheets. The remaining carbons form isolated sp2 graphene like networks. On reduction the oxygen functionalities are removed and the sp2 network partially restored. This thesis focuses on the aqueous dispersibility of GO and r -GO, and describes a strategy to enhance the dispersibility of r -GO by cyclodextrin functionalization. Chapter 1 of the thesis provides a brief review of the synthetic procedures and structure of GO and r -GO while Chapter 2 describes the experimental methods and characterization techniques used in the thesis. The chemistry underlying the aqueous dispersibility of GO and r -GO at different values of pH have been investigated by zeta potential measurements, pH titrations and infrared spectroscopy (Chapter 3). These measurements show that r -GO sheets have ionizable groups with a single pKa value (8.0) while GO sheets have groups that are more acidic (pKa = 4.3), in addition to groups with pKa values of 6.6 and 9.0. Infrared spectroscopy has been used to follow the sequence of ionization events. In both GO and r -GO sheets, it is ionization of the carboxylic groups that is primarily responsible for the build up of charge, but on GO sheets, the presence of phenolic and hydroxyl groups in close proximity to the carboxylic groups lowers the pKa value by stabilizing the carboxylate anion, resulting in superior water dispersibility. Till recently GO was primarily considered only as an easily available precursor for chemical routes to r -GO but it has now been recognized as an interesting material in its own right. Two such attributes that have attracted wide spread attention are the in- trinsic and tunable fluorescence of GO as well as formation of liquid crystalline phases. Aqueous dispersions of GO exhibit strong pH dependent fluorescence in the visible region that originates, in part, from the oxygenated functionalities present. In Chapter 4, the spectral migration on nanosecond timescales of the pH dependent features in the fluores- cence spectra of GO is described. The changes in the steady state fluorescence spectra with pH have been correlated with the sequence of dissociation events that occur in GO dispersions at different values of pH described in Chapter 3, from time resolved emission spectra (TRES) constructed from the wavelength dependent fluorescence decay curves, it is shown that the migration is associated with excited state proton transfer. Both ‘intramolecular’ and ‘intermolecular’ transfers involving the quasimolecular oxygenated aromatic fragments are observed. Aqueous dispersions of GO constitute a distinctive class of 2D-anisotropic colloids with competing interactions - long range electrostatic repulsion, originating from ionized carboxylic groups located on the rim of the sheets and weak dispersive attractive interactions originating from the un-oxidized sp2 graphitic domains. In Chapter 5, it is shown that, colloidal dispersions of GO are intrinsically frustrated, exhibiting a range of arrested or metastable states, encompassing fluid, glass and gels that coexist with liquid crystalline order. These states can be accessed by varying the relative magnitudes of the repulsive and attractive forces by changing the ionic strength of the medium, by addition of salt and/or the concentration of the dispersion. At low salt concentrations, where long range electrostatic repulsions dominates, the formation of a repulsive Wigner glass is observed while at high salt concentrations, when attractive forces dominate, the formation of gels that exhibits a nematic to columnar liquid crystalline transition. These studies highlights how the chemical structure of GO - hydrophilic ionizable groups and hydrophobic graphitic domains coexisting on a single sheet - gives rise to a rich and complex phase diagram. The poor dispersibility of r -GO in aqueous media limits its use in practical applica- tions. To enhance the dispersibility, r -GO sheets have been functionalized by covalently linking -cyclodextrin ( -CD) cavities to the sheets via an amide linkage (Chapter 6). The functionalized -CD: rGO sheets, in contrast to r -GO, are dispersible over a wide range of pH values (2 - 13). Zeta potential measurements indicate that there is more than one factor responsible for the dispersibility. It is shown that planar aromatic molecules adsorbed on the r -GO sheet as well as nonplanar molecules included in the tethered -CD cavities have their fluorescence effectively quenched by the -CD: rGO sheets. The -CD: rGO sheets combine the hydrophobicity associated with r -GO along with the hydrophobicity of the cyclodextrin cavities in a single water dispersible material. Resonance Raman spectroscopy is a powerful analytical tool for detecting and identi- fying analytes, but the associated strong fluorescence background severely limits the use of the technique. In Chapter 7, it is shown that the cyclodextrin functionalized -CD: rGO sheets, described in Chapter 6, provides a versatile platform for resonance Raman detection. Planar aromatic and dye molecules that adsorb on the r -GO graphitic domains and non-planar molecules included within the tethered -CD cavities have their fluorescence effectively quenched. Using the water dispersible -CD: rGO sheets, it is possible to record the resonance Raman spectra of adsorbed and included organic chromophores directly in aqueous media without having to extract or deposit on a substrate. The Raman signal intensities show a linear dependence with the concentration of analyte present in water. This is significant, as it allows for the identification and estimation of organic analytes present in water by resonance Raman spectroscopy.

Detta kandidatarbete undersöker Pierre Schaeffers (2012 [1952]) begrepp musique concrète samt dess metoder och tekniker. Musique concrète kan beskrivas som en samling kompositionsmetoder som utgår från inspelade ljud av omvärlden utan inblandning av musikinstrument, musikteori, eller ljud genererade från elektroniska källor. Vi använde Schaffers begrepp reduced listening, vilket är en lyssningsmetod där man bortser från ljudets källa och fokuserar på dess akustiska egenskaper, (vilket Michel Chion (1994) senare expanderade på). Jøran Rudi (2011) skriver om R. Murray Schafer’s begrepp Hi-Fi och Lo-Fi, vilket vi använde för att kategorisera ljuden som användes och platserna som spelades in. I designprocessen applicerade och experimenterade vi med metoder och tekniker från den aktuella forskningen för att utforska och dokumentera arbetsprocessen i gestaltningsprototyperna. Detta arbete resulterade i en samling kompositioner utefter Lo-Fi och Hi-Fi inom musique concrète där vi fick en bredare förståelse för de aktuella metoderna och teknikerna. / This bachelor thesis examines Pierre Schaeffer’s (2012 [1952]) term musique concrète as well as it’s methods and techniques. Musique concrète can be described as a collection of compositional methods that uses recorded sounds from the surrounding world as a startingpoint, without the use of musical instruments, music theory, or electronically produced sounds. We used Schaeffer’s term reduced listening (which Michel Chion (1994) later expanded upon). Jøran Rudi (2011) writes about R. Murray Schafer’s term Hi-Fi and Lo-Fi,and these terms were later used by us to categorise and record sounds from the environment. Investigation and experimentation with the various methods and techniques ensued in the design process in order to explore and document the work process of the prototypes. This process resulted in a collection of musique concrète compositions stemming from the Lo-Fi och Hi-Fi processes through which we gained more knowledge and understanding of themethods and techniques involved.