• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 117
  • 82
  • 6
  • 5
  • 4
  • 4
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 231
  • 140
  • 111
  • 86
  • 52
  • 39
  • 39
  • 35
  • 34
  • 34
  • 31
  • 30
  • 28
  • 26
  • 25
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Redox cycling for an in-situ enzyme labeled immunoassay on interdigitated array electrodes

Kim, Sangkyung 20 August 2004 (has links)
This research is directed towards developing a more sensitive and rapid electrochemical sensor for enzyme labeled immunoassays by coupling redox cycling at interdigitated electrode arrays (IDA) with the enzyme label b-galactosidase. Coplanar and comb IDA electrodes with a 2.4 mm gap were fabricated and their redox cycling currents were measured. ANSYS was used to model steady state currents for electrodes with different geometries. Comb IDA electrodes enhanced the signal about 3 times more than the coplanar IDAs, which agreed with the results of the simulation. Magnetic microbead-based enzyme assay, as a typical example of biochemical detection, was done using the comb and coplanar IDAs. The enzymes could be placed close to the sensing electrodes (~10 mm for the comb IDAs) and detection took less than 1 min with a limit of detection of 70 amole of b-galactosidase. We conclude that faster and more sensitive assays can be achieved with the comb IDA. A paramagnetic bead assay has also been demonstrated for detection of bacteriophage MS2, used as a simulant for biothreat viruses, such as small pox. The immunoassay was carried out in a microfluidic format with the IDA, reference and counter electrodes integrated on the same chip. Detection of 90 ng/mL MS2 or 1.5x1010 MS2 particles/mL was demonstrated.
112

Modeling Consciousness: A Comparison Of Computational Models

Gok, Selvi Elif 01 September 2009 (has links) (PDF)
There has been a recent flurry of activity in consciousness research. Although an operational definition of consciousness has not yet been developed, philosophy has come to identify a set of features and aspects that are thought to be associated with the various elements of consciousness. On the other hand, there have been several recent attempts to develop computational models of consciousness that are claimed to capture or illustrate one or more aspects of consciousness. As a plausible substitute to evaluating how well the current computational models model consciousness, this study examines how the current computational models fare in modeling those aspects and features of consciousness identified by philosophy. Following a detailed and critical review of the literature of philosophy of consciousness, this study constructs a composite and eclectic list of features and aspects that would be expected in any successful model of consciousness. The study then evaluates, from the viewpoint of that list, some of the current self-claimed computational models of consciousness, specifically CLARION, IDA, ACT-R and model proposed in the Cleeremans&#039 / review and study. The computational models studied are evaluated with respect to each identified aspect and feature of consciousness.
113

Ida B. Wells, Catherine Impey, and trans-Atlantic dimensions of the nineteenth century anti-lynching movement

Jordan, Brucella Wiggins. January 1900 (has links)
Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains v, 298 p. Includes abstract. Includes bibliographical references (p. 286-298).
114

Effekter vid tilläggsisolering av kallvindar ur fuktsynpunkt / Moisture effects of additional insulation in cold attics

Schill, Elin, Flodins, Tina January 2015 (has links)
Ekonomiska aspekter och krav på minskad energianvändning leder bland annat till tilläggsisolering av vindsbjälklag och byte av uppvärmningssystem. Åtgärderna ger ett kallare och fuktigare klimat på vinden vilket gynnar mögeltillväxt. Minst 60 % av alla traditionella vindar med självdrag kan anses ha riklig tillväxt av mögelsvamp (Ahrenens och Borglund 2007). Syftet med denna studie är att ta ett steg i rätt riktning om vilka åtgärder som kan göras på de vindar som idag är angripna. I denna studie har tre vindars fukttillstånd utretts och jämförts. Ett av objekten har simulerats och utsatts för olika åtgärder. Simuleringarna bekräftar att minskad isolering ger ett torrare klimat på vinden. En ökning av ventilationen ger liten men knappt märkbar förbättring av vindsklimatet. Hög värmekapacitivitet hos isoleringsmaterial verkar ge en jämnare temperatur på vinden vilket sänker luftfuktigheten. Genom att isolera vindens tak och gavlar sker en markant sänkning av mögelrisken. Då varje vind är olika uppbyggd finns ingen generell lösning utan varje vind måste bedömas utifrån sina nuvarande förhållanden.
115

Telling a different geographic story : garreting, license, and the making of Chicago's Ida B. Wells Homes

Quesal, Susan 18 November 2010 (has links)
The Ida B. Wells Homes, the first black-occupied housing project built in Chicago, were completed in 1941. Throughout their construction and inhabitation, the black community in Chicago worked to create a self-contained space which would control the visibility/invisibility of its black inhabitants and, symbolically, the black community as a whole. Taking as theoretical grounding Katherine McKittrick’s work on garreting and Susan Lepselter’s work on license, this essay argues that the Ida B. Wells Homes were a South Side garret for the black community, a space in which freedom became defined by its own boundaries and wherein this freedom could work in tandem with dominant geographies of oppression to construct a “different” geographic story. This “different” geography intended to alter perceptions of black life by working against dominant geographic narratives that were prevalent at the time, such as those put forth by the Chicago School of Sociology. / text
116

E-Editionen zur neuen Praxis der Editionsphilologie ; Ida und Richard Dehmel - Harry Graf Kessler ; Briefwechsel 1898-1935 /

Kamzelak, Roland. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2004--Tübingen.
117

Ανάλυση και πειραματική εφαρμογή ελέγχου σε αντιστροφέα δυο βαθμίδων (DC/DC και DC/AC) για σύνδεση φωτοβολταϊκού συστήματος

Πέγκος, Οδυσσέας 24 October 2012 (has links)
Στις μέρες μας, οι ολοένα αυξανόμενες ενεργειακές ανάγκες καθώς και οι η μόλυνση του περιβάλλοντος είναι οι κύριοι λόγοι που η χρήση των ανανεώσιμων πηγών ενέργειας στα σύγχρονα συστήματα ενέργειας έχει αυξηθεί τις τελευταίες δεκαετίες. Τα φωτοβολταϊκά συστήματα είναι μια από τις πιο συνήθεις και αποτελεσματικές ανανεώσιμων πηγών για συνδεδεμένα στο δίκτυο ή αυτόνομα συστήματα. Ο σκοπός της παρούσας εργασίας είναι η μελέτη και προσομοίωση έλεγχου σε μετατροπέα δυο βαθμίδων για σύνδεση φωτοβολταικού συστήματος. Αρχικά, θα μελετήσουμε θεωρητικά διάφορους τύπους τοπολογιών που περιλαμβάνουν αντιστροφέα, στην περίπτωση μας, θα μοντελοποιήσουμε και προσομοιώσουμε ένα DC-DC μετατροπέα σε σύνδεση αλυσίδας με έναν τριφασικό DC-AC αντιστροφέα σε ένα απομονωμένο σύστημα. Ειδικότερα θα παρουσιάσουμε θεωρητικά και πειραματικά αποτελέσματα έλεγχου της τάσης εξόδου του μετατροπέα. Το βασικό κομμάτι αυτής της εργασίας είναι τα αποτέλεσμα του ελεγκτή που είναι βασισμένος στην παθητικότητα διασύνδεσης και εκχώρηση απόσβεσης (IDA PBC). Τέλος, θα μοντελοποιήσουμε και προσομοιώσουμε τον DC-AC μετατροπέα, του οποίου ελέγχουμε την τάση εξόδου από τους γνωστούς μας σε όλους αναλογικούς-ολοκληρωτικούς (PI) ελεγκτές. / Nowadays, increased energy needs and the increasing pollution levels of the environment are the main reasons that usage of renewable energy sources to modern power systems has significantly increased in the last decades. Photovoltaic (PV) generator systems are one of the most common and efficient renewable energy applications for grid-connected or stand-alone systems. The aim of the present thesis is the study and the simulation of control of a two level power converter used in photovoltaic systems. Firstly, we will study theoretically different types of topologies that include inverters, in our case, we model and simulate a DC-DC boost power converter string connected with a three phase DC-AC inverter to a stand-alone system. Especially we will present theoretical and experimental results controlling the DC-DC converter output voltage. The basic part of this thesis are the results of the controller, which is designed following the passivity-based interconnection and damping assignment methodology (IDA PBC). Finally, we will model and simulate the DC-AC inverter, where its output voltage is controlled by the well-known, proportional-integral (PI) controllers.
118

Alternative energy supply study for a cottage in Vifors

Lumbier Fernandez, Mikel January 2018 (has links)
The present master thesis was done during the spring of 2018. A cottage located in Vifors is studied with regard to its heating requirements. At the time of the study, the house could not be inhabited the whole year because there was no tap hot water available and the space heating demand was covered by electricity. Thus, an alternative heating supply is required to be developed. As a strategic prerequisite, the solution should be achieved considering both solar thermal collectors and a heat pump.First, the characteristics of the building were collected/determined in order to obtain the total heating demand per month and hence annually. Parameters such as the U-values, roof orientation, room dimensions, ventilation rates and internal gains were required to configure the building model in the software IDA ICE 4.8. In addition, the amount of tap hot water required per year was determined as 17 m3 per year. Cold water at 5 °C had to be heated until 55 °C to obtain the tap hot water.Once the heating requirements were known, the most suitable solution was to use a combi system (solar thermal collectors and a heat pump). Solar energy could fulfil the demand in the summer and the heat pump provided energy in the winter. For a commercial model of the flat solar thermal collector (Vitosol 100-F) the solar system was sized according to the heating demand in the summer time. The maximum energy that could be obtained from the solar collectors in summer was calculated, the rest of the demand had to be fulfilled by a heat pump, model WPL-18 E.The achieved solution is compounded by the heat pump and 3 solar thermal collectors with a surface of 2.33 m2 each. The solar energy obtained is 1 843 kWh per year, which covers 9 % of the total annual heating demand (20 098 kWh). However, the 98 % of the heating demand during the summertime comes from the solar collectors. The investment cost is 113 900 SEK and the payback period is estimated in 8 years.
119

Betydelsen av en byggnads planlösning vid energieffektivisering : Enligt simulering i IDA ICE / The significance of building planning in energy streamlining

Eskills, Jonathan January 2018 (has links)
I Sverige står bostad och servicesektorn för cirka 40 % av den totala energianvändningen. 90 % av denna energi används till hushåll och lokaler, vilket betyder att dess energianvändning endast överstigs av industrins. En god strategi för en minskad nationell energianvändning är därför att energieffektivisera både befintliga byggnader och nyproduktion. Detta arbete har i syfte att undersöka hur olika typer av energieffektiviseringar påverkar kontorsbyggnader ur en energisynpunkt beroende på deras planlösning. Arbetet kommer att jämföra två verkliga byggnader som har samma yttre dimension och konstruktion, men där en av byggnaderna har en jämförelsevis öppnare planlösning. Fem olika energieffektiviseringar kommer att simuleras utifrån programvaran EQUA IDA ICE; en sänkning av inomhustemperaturen, en ökad verkningsgrad på luftbehandlingsaggregatets värmeväxlare, ett minskat U-värde på fönster, Ett minskat U-värde på tak samt en ändring av värmesystemets styrsystem till proportionell från proportionellt integrerande. Resultatet visar att: En sänkning av inomhustemperaturen med 2 ˚C minskar behovet av värme till luftbehandlingsaggregatet för den öppna byggnaden med 42,5 %, och 35,8 % för den mindre öppna. Effekterna av en ökad verkningsgrad från 0,6 till 0,9 på värmeväxlaren i luftbehandlingsaggregatet, är oberoende av en byggnads planlösning. Vid ett minskat U-värde på fönster från 1,8 till 1,1 W/m2,K så ökas den tillförda kylan till luftbehandlingsaggregatet med 130 % för byggnaden med den öppna planlösningen, och för den mindre öppna byggnaden så påverkas inte behovet. Vid ett minskat U-värde på taket från 0,09 till 0,05 W/m2,K så har byggnaden med den öppna planlösningen en bättre prestanda för tillförd värme till både värmesystem och luftbehandlingsaggregat. När styrsystemet för värmesystemetet ändras till proportionellt från proportionellt integrerande, så ökar kylbehovet för värmesystemet för byggnaden med den öppnare planlösningen med 4,1 %, och den mindre öppna byggnaden får en större ökning på 17,7 %. En mindre öppen planlösning får en större påverkan av energieffektiviseringar på ventilation- och värmesystem i jämförelse med en mer öppen. En öppen planlösning får en större påverkan av energieffektiviseringar som minskar U-värdet på konstruktionen i jämförelse med en mindre öppen planlösning. / The residence and service sector stand for 40 % of the total energy use in Sweden. 90 % of that energy is used for households and facilities, which means that its energy use is only surpassed by that of the industry An appropriate solution for a national reduction in use of energy is therefore to streamline the energy efficiency for existing and planned buildings. The aim for this academic work is to examine how different methods of streamlining energy use is affected by building planning. Two real life buildings are to be compared and analysed. The buildings have identical outer dimensions and construction, and one of them has a comparatively more open building plan. Five different streamlining solutions are going to be simulated in the software EQUA IDA ICE; a lowering of the room temperature, an increased efficiency on the heat exchanger in the air handling unit, a decreased U-value (a Swedish building standard in energy transmission) for the windows, a decreased U-value for the roof and lastly a change from a proportional control system to a proportional integrating on the heating and cooling system. The results show that: A lowering of the room temperature by 2 ˚C, lessens the heating load for the air handling unit by 42,5 % in the building with a more open building plan, whilst the less open building sees a decrease of 35,8 %. The effect of an increased efficiency from 0,6 to 0,9 on the heat exchanger in the air handling is unaffected by a buildings planning. A lowered U-value for the windows from 1,8 to 1,1 W/m2,K increases the cooling load for the air handling unit by 130 % on the building with the more open planning. And at the same time the building with the less open planning is unaffected by the streamlining. A lowered U-value for the roof from 0,09 to 0,05 W/m2,K gives an increased performance on the heating load for both the heating system and air handling unit on the building with the more open planning, compared to that of the less open building. If the control system of the heating and cooling systems changes from a proportional integrating to a proportional one, the cooling load for the cooling system increases by 4,1 % on the building with the more open planning, whilst it increases by 17,1 % on the less open building. Streamlining the energy use of ventilation, cooling and heating systems has a bigger impact on buildings with a more open planning compared to those with a less open building plan. A less open building plan is better affected by the streamlining of the energy transmission trough the construction compared to a more open planning.
120

ENERGY ASSESMENT FOR MODULARDETACHED BUILDINGS : Case studies, Sweden and Spain.

Alba Vázquez, Cira January 2018 (has links)
Energy assessment in buildings is an essential topic in order to achieve the set goals for energy efficiency. This thesis investigated the energy consumption in various scenarios in Husmuttern’s buildings. Different purposes (school and apartment), locations (Spain and Sweden) and materials combinations are modelled and analysed. The models were created in the building performance simulation tool IDA ICE. After the yearly energy demand results were obtained they were processed and analysed. Then several factors were changed in the model in order to investigate different impacts in the energy consumption of the building, such as the overall heat transfer, hot water consumption, windows and doors. Also, PV panels were installed in the model to obtain the potential penetration of renewable energy in the buildings. The results showed the different consumption in the buildings depending on the purpose and location, and the impact of the changed factors in the overall energy consumption. The change of windows to more efficient ones showed that the apartments improve their consumption more than the schools, especially in when the Spanish location is considered. This case also had the biggest possible change when the hot water demand is varied. Whereas if the door was the changed, the Swedish apartment has the most possible improvement.

Page generated in 0.027 seconds