The homodimeric Ocr protein of bacteriophage T7 is a molecular mimic of a bent double-stranded DNA molecule ~24 bp in length. As such, Ocr is a highly effective competitive inhibitor of the bacterial Type I restriction modification (R/M) system. Thus, Ocr facilitates phage infection of the bacterial cell to proceed unhindered by the action of the R/M defense system. The main aim of this work was to understand the basis of the DNA mimicry displayed by Ocr. The surface of the protein is replete with acidic residues, most or all of which mimic the phosphate backbone of DNA. Aspartate and glutamate residues on the surface of Ocr were either mutated or chemically modified in order to investigate their contribution to the tight binding between Ocr and the EcoKI Type I R/M enzyme. Single or double mutations of Ocr had no discernable effect on binding to EcoKI or its methyltransferase component (M.EcoKI). Chemical modification was then used to specifically modify the carboxyl moieties of Ocr, thereby neutralizing the negative charges on the protein surface. Ocr samples modified to varying degrees were analysed to establish the extent of derivatisation prior to extensive biophysical characterisation to assess the impact of these changes in terms of binding to the EcoKI R/M system. The results of this analysis revealed that the electrostatic mimicry of Ocr increases the binding affinity for its target enzyme by at least ~800-fold. In addition, based on the known 3-D structure of the protein, a set of multiple mutations were introduced into Ocr aimed at eliminating patches of negative charge from the protein surface. Specifically, between 5 and 17 acidic residues were targeted for mutation (Asp and Glu to Asn and Gln, respectively). Analysis of the in vivo activity of the mutant Ocr along with biophysical characterisation of the purified proteins was then performed. Results from these studies identified regions of the Ocr protein that were critical in forming a tight association with the EcoKI R/M system. Furthermore by comparing the relative contribution of different groups of acidic residues to the free energy of binding, the actual mechanism by which Ocr mimics the charge distribution of DNA has been delineated.

<p>Som ett led i att minska växthuseffekten och den globala uppvärmningen gäller det att minskautsläppen av koldioxid. En stor del av den koldioxid som släpps ut inom energisektornkommer från elproduktion i kolkondenskraftverk. Dessa utsläpp kan minskas genomutbyggnad av kraftvärme, det vill säga samtidig produktion av värme och el. Ett sätt att göradet är att komplettera befintliga, småskaliga värmeverk med elproduktion via enproduktionsintegrerad ORC-krets (Organisk Rankinecykel). Syftet med den här studien är attge en uppfattning om de tekniska och ekonomiska förutsättningarna, vid installation av enproduktionsintegrerad ORC-krets. Syftet är också att jämföra dessa förutsättningar medförutsättningarna vid installation av den alternativa flashtekniken.En Organisk Rankinecykel (ORC) fungerar som en konventionell Rankinecykel(ångkraftcykel), med en ångturbin och generator som genererar el. Skillnaden är attarbetsmediet i kretsen är organiskt, istället för vatten. Exempel på arbetsmedier är olikafreoner, köldmedier, ammoniak och kolväten. Vilket arbetsmedium som väljs är beroende avtemperaturer och flöden.Studien har baserats på ett typiskt fjärrvärmesystem av storleken 20 MW, med enbiobränslepanna på 10 MW, en rökgaskondensor med storleken 20 % av biobränslepannanseffekt samt en oljespetspanna för att täcka resterande behov.Tre systemkoncept har studerats.Lastintegrerad ORC: Är det traditionella inkopplingssättet av ORC-enheter (kondensdrift),där den i det här fallet ansluts som en vanlig fjärrvärmekund. Nackdelen med detta koncept, äratt en stor mängd värme försvinner till omgivningen via ORC-enhetens kylning.Produktionsintegrerad ORC: Tanken här är att ORC-enheten installeras direkt efter systemetspanna. Restvärmen från ORC-enheten matas sedan tillbaka till systemet och kan användassom betald fjärrvärme istället för att kylas bort.Flashtekniken: I detta koncept produceras vattenånga från hetvatten i en ånggenerator. Ångangår sedan genom en enkel ångturbin med generator och el genereras. Efter turbinen användsångan till att värma vattnet till fjärrvärmenätet.Studien har visat att lastintegrerad ORC genererar en förlust varje år och är ett koncept sominte är lönsamt. Produktionsintegrerad ORC och flashtekniken genererar båda en vinst varjeår. Flashtekniken är dock mer lönsamt, främst för att verkningsgraden är aningen högrejämfört med ORC. Vidare verkar flashtekniken ha lägre investeringskostnader dåkomponenterna är färre och enklare. Detta ger en indikerande pay-off tid mellan 8 och 12 årför ORC, respektive mellan 5 och 9 år för flashtekniken.</p> / <p>A part of reducing the increased greenhouse effect is to reduce emissions of carbon dioxide.Much of the carbon dioxide emitted by the energy sector comes from electricity produced incondensing power plants. These emissions can be reduced by the development ofcogeneration, i.e. simultaneous production of heat and electricity. One way to do this is tocomplement the existing, small-scale heat plants with electricity production via a productionintegrated ORC (Organic Rankine Cycle). The purpose of this study is to give an idea of thetechnical and economical conditions, when installing a production integrated ORC. Thepurpose is also to compare these conditions with the conditions for the alternative flashtechnology.An Organic Rankine Cycle (ORC) works as a conventional Rankine Cycle (steam poweredcycle), with a steam turbine and generator that generates electricity. The difference is that thefluid in the circuit is organic, instead of water. Examples of organic fluids are CFCs,refrigerants, ammonia and hydrocarbons. Which fluid is chosen depends on the temperaturesand flows.The study was based on a typical district heating systems of size 20 MW, with a biomass firedboiler of 10 MW, a flue gas condenser with size 20% of the biomass fired boiler power tipand an oil boiler to meet remaining needs.Three system concepts were studied.Load integrated ORC: Is the traditional way of connecting ORC units (condensation mode), inthis case it is connected as an ordinary district heating customers. The downside of thisconcept is that a large amount of heat is lost to the atmosphere, via the ORC device coolingsystem.Production integrated ORC: The idea here is that the ORC unit is installed directly after theboiler. Residual heat from the ORC unit is then fed back into the system and can be used aspaid heat in the district heating system, instead of cooling it off.Flash Technology: In this concept steam is produced from hot water in a steam generator. Thesteam then goes through a steam turbine and generates electricity. After the turbine, the steamis used to heat the water for the district heating system.The study has shown that the load integrated ORC generates a loss each year and is a conceptwhich is, under the assumptions being made, not profitable. Production integrated ORC andflash technology both generates a profit every year. Flash technology is more profitable,primarily for the efficiency is slightly higher compared to the ORC. Further, flash technologyseems to have lower investment costs because the components are fewer and simpler. Thisgives an indicated pay-off time between eight and 12 years for ORC, and between five andnine years of Flash technology.</p>

This thesis research aims to develop an improved, efficient, low-capacity heat engine, running on an Organic Rankine Cycle (ORC) to generate power. The ORC is driven by low or moderate temperature heat sources, such as; renewable energy in the form of a hot gas derived from biomass/biogas/biofuel combustion streams, waste heat recovery, process heat recovery, etc. The ORC is more suitable and flexible than a conventional steam Rankine cycle, especially when it is applied to low power range. In this research, an extended surface heat exchanger is used to boil the pressurised working fluid, R134a, using a hot air as heat source. The expander used is a scroll type, coupled to a generator, which is able to produce maximum 1.6 kW output. Experimental data of the heat engine are measured under different operating conditions and utilized in the analysis and comparisons. Power generation under various conditions is investigated in order to determine the optimum performance parameters for the heat engine. The isentropic efficiency of the expander is found to be over 40% and reaches 80% for the improved expansion conditions. For the boiler, it is determined that the overall heat transfer coefficient multiplied with the heat transfer area is around 150 W/K. The energy efficiency of the experimental ORC is around 3% for hot air as the low temperature heat source at about 105oC where exergy efficiency reaches 22%, respectively. / UOIT

The heterohexameric origin recognition complex (ORC) acts as a scaffold for the G1 phase assembly of pre-replicative complexes. Only the Orc1-5 subunits are required for origin binding in budding yeast, yet Orc6 is an essential protein for cell proliferation. In comparison to other eukaryotic Orc6 proteins, budding yeast Orc6 appears to be quite divergent. Two-hybrid analysis revealed that Orc6 only weakly interacts with other ORC subunits. In this assay Orc6 showed a strong ability to self-associate, although the significance of this dimerization or multimerization remains unclear. Imaging of Orc6-eYFP revealed a punctate sub-nuclear localization pattern throughout the cell cycle, representing the first visualization of replication foci in live budding yeast cells. Orc6 was not detected at the site of division between mother and daughter cells, in contrast to observations from metazoans. An essential role for Orc6 in DNA replication was identified by depleting the protein before and during G1 phase. Surprisingly, Orc6 was required for entry into S phase after pre-replicative complex formation, in contrast to what has been observed for other ORC subunits. When Orc6 was depleted in late G1, Mcm2 and Mcm10 were displaced from chromatin, the efficiency of replication origin firing was severely compromised, and cells failed to progress through S phase. Depletion of Orc6 late in the cell cycle indicated that it was not required for mitosis or cytokinesis. However, Orc6 was shown to be associated with proteins involved in regulating these processes, suggesting that it may act as a signal to mark the completion of DNA replication and allow mitosis to commence.

Som ett led i att minska växthuseffekten och den globala uppvärmningen gäller det att minskautsläppen av koldioxid. En stor del av den koldioxid som släpps ut inom energisektornkommer från elproduktion i kolkondenskraftverk. Dessa utsläpp kan minskas genomutbyggnad av kraftvärme, det vill säga samtidig produktion av värme och el. Ett sätt att göradet är att komplettera befintliga, småskaliga värmeverk med elproduktion via enproduktionsintegrerad ORC-krets (Organisk Rankinecykel). Syftet med den här studien är attge en uppfattning om de tekniska och ekonomiska förutsättningarna, vid installation av enproduktionsintegrerad ORC-krets. Syftet är också att jämföra dessa förutsättningar medförutsättningarna vid installation av den alternativa flashtekniken.En Organisk Rankinecykel (ORC) fungerar som en konventionell Rankinecykel(ångkraftcykel), med en ångturbin och generator som genererar el. Skillnaden är attarbetsmediet i kretsen är organiskt, istället för vatten. Exempel på arbetsmedier är olikafreoner, köldmedier, ammoniak och kolväten. Vilket arbetsmedium som väljs är beroende avtemperaturer och flöden.Studien har baserats på ett typiskt fjärrvärmesystem av storleken 20 MW, med enbiobränslepanna på 10 MW, en rökgaskondensor med storleken 20 % av biobränslepannanseffekt samt en oljespetspanna för att täcka resterande behov.Tre systemkoncept har studerats.Lastintegrerad ORC: Är det traditionella inkopplingssättet av ORC-enheter (kondensdrift),där den i det här fallet ansluts som en vanlig fjärrvärmekund. Nackdelen med detta koncept, äratt en stor mängd värme försvinner till omgivningen via ORC-enhetens kylning.Produktionsintegrerad ORC: Tanken här är att ORC-enheten installeras direkt efter systemetspanna. Restvärmen från ORC-enheten matas sedan tillbaka till systemet och kan användassom betald fjärrvärme istället för att kylas bort.Flashtekniken: I detta koncept produceras vattenånga från hetvatten i en ånggenerator. Ångangår sedan genom en enkel ångturbin med generator och el genereras. Efter turbinen användsångan till att värma vattnet till fjärrvärmenätet.Studien har visat att lastintegrerad ORC genererar en förlust varje år och är ett koncept sominte är lönsamt. Produktionsintegrerad ORC och flashtekniken genererar båda en vinst varjeår. Flashtekniken är dock mer lönsamt, främst för att verkningsgraden är aningen högrejämfört med ORC. Vidare verkar flashtekniken ha lägre investeringskostnader dåkomponenterna är färre och enklare. Detta ger en indikerande pay-off tid mellan 8 och 12 årför ORC, respektive mellan 5 och 9 år för flashtekniken. / A part of reducing the increased greenhouse effect is to reduce emissions of carbon dioxide.Much of the carbon dioxide emitted by the energy sector comes from electricity produced incondensing power plants. These emissions can be reduced by the development ofcogeneration, i.e. simultaneous production of heat and electricity. One way to do this is tocomplement the existing, small-scale heat plants with electricity production via a productionintegrated ORC (Organic Rankine Cycle). The purpose of this study is to give an idea of thetechnical and economical conditions, when installing a production integrated ORC. Thepurpose is also to compare these conditions with the conditions for the alternative flashtechnology.An Organic Rankine Cycle (ORC) works as a conventional Rankine Cycle (steam poweredcycle), with a steam turbine and generator that generates electricity. The difference is that thefluid in the circuit is organic, instead of water. Examples of organic fluids are CFCs,refrigerants, ammonia and hydrocarbons. Which fluid is chosen depends on the temperaturesand flows.The study was based on a typical district heating systems of size 20 MW, with a biomass firedboiler of 10 MW, a flue gas condenser with size 20% of the biomass fired boiler power tipand an oil boiler to meet remaining needs.Three system concepts were studied.Load integrated ORC: Is the traditional way of connecting ORC units (condensation mode), inthis case it is connected as an ordinary district heating customers. The downside of thisconcept is that a large amount of heat is lost to the atmosphere, via the ORC device coolingsystem.Production integrated ORC: The idea here is that the ORC unit is installed directly after theboiler. Residual heat from the ORC unit is then fed back into the system and can be used aspaid heat in the district heating system, instead of cooling it off.Flash Technology: In this concept steam is produced from hot water in a steam generator. Thesteam then goes through a steam turbine and generates electricity. After the turbine, the steamis used to heat the water for the district heating system.The study has shown that the load integrated ORC generates a loss each year and is a conceptwhich is, under the assumptions being made, not profitable. Production integrated ORC andflash technology both generates a profit every year. Flash technology is more profitable,primarily for the efficiency is slightly higher compared to the ORC. Further, flash technologyseems to have lower investment costs because the components are fewer and simpler. Thisgives an indicated pay-off time between eight and 12 years for ORC, and between five andnine years of Flash technology.

The heterohexameric origin recognition complex (ORC) acts as a scaffold for the G1 phase assembly of pre-replicative complexes. Only the Orc1-5 subunits are required for origin binding in budding yeast, yet Orc6 is an essential protein for cell proliferation. In comparison to other eukaryotic Orc6 proteins, budding yeast Orc6 appears to be quite divergent. Two-hybrid analysis revealed that Orc6 only weakly interacts with other ORC subunits. In this assay Orc6 showed a strong ability to self-associate, although the significance of this dimerization or multimerization remains unclear. Imaging of Orc6-eYFP revealed a punctate sub-nuclear localization pattern throughout the cell cycle, representing the first visualization of replication foci in live budding yeast cells. Orc6 was not detected at the site of division between mother and daughter cells, in contrast to observations from metazoans. An essential role for Orc6 in DNA replication was identified by depleting the protein before and during G1 phase. Surprisingly, Orc6 was required for entry into S phase after pre-replicative complex formation, in contrast to what has been observed for other ORC subunits. When Orc6 was depleted in late G1, Mcm2 and Mcm10 were displaced from chromatin, the efficiency of replication origin firing was severely compromised, and cells failed to progress through S phase. Depletion of Orc6 late in the cell cycle indicated that it was not required for mitosis or cytokinesis. However, Orc6 was shown to be associated with proteins involved in regulating these processes, suggesting that it may act as a signal to mark the completion of DNA replication and allow mitosis to commence.

This dissertation presents the concurrent programming language Ora, an extension of the Orc orchestration language with the capability to execute transactions. A new formal definition of transactions is given, in terms of two complementary properties: atomicity and coatomicity. These properties are described in terms of a partial order of events, rather than as properties of a totally ordered program trace. Atomicity and coatomicity are ensured in Ora programs by a novel algorithm for multiversion concurrency control. / text

Zugl.: Bayreuth, Univ., Diss., 2007

Zugl.: Bayreuth, Universiẗat, Diss., 2008.

La recuperaci´on de la potencia t´ermica residual existente en los motores de automoci´on se muestra como una v´ıa para el aumento de su eficiencia. Muchos estudios en la literatura han mostrado un potencial de recuperaci´on de hasta el 15 %. En la mayor parte de los casos, las investigaciones est´an basadas en estudios te´oricos, o bien, basadas en resultados experimentales de prototipos alimentados con generadores de gases que simulan los gases de escape de un motor en condiciones estacionarias. El objetivo principal de este trabajo, es la evaluaci´on te´orico-experimental del potencial de recuperaci´on de un sistema de aprovechamiento energ´ıa t´ermica residual mediante un ciclo Rankine, aplicado en motores de combusti´on interna alternativos y en condiciones estacionarias de funcionamiento. La finalidad de este sistema ser´a conseguir una mejora en la eficiencia de los motores de automoci´on, y la consiguiente reducci´on en consumo de combustible y en emisiones de contaminantes. La metodolog´ıa que se ha seguido para realizar el trabajo, combina actividades experimentales en banco de ensayo de motor, con el desarrollo de estudio te´oricos basados en modelos 0-D para la evaluaci´on te´orica de diferentes configuraciones de ciclo y fluidos de trabajo. La interacci´on entre ambas actividades ha permitido alcanzar los objetivos planteados. Respecto los trabajos te´oricos, se ha realizado una metodolog´ıa que permite una evaluaci´on sencilla y ordenada de las prestaciones del ciclo Rankine para diferentes fluidos de trabajo, condiciones de ciclo, y secuencias de fuentes residuales a utilizar, considerando ciclos de aprovechamiento de naturaleza ideal. Posteriormente, se ha realizado un estudio de viabilidad t´ecnica de ciclos Rankine para diferentes motores, con el fin de obtener informaci´on sobre la tipolog´ıa de los elementos constructivos a utilizar (expansores e intercambiadores), criterios de dise˜no, y prestaciones finales del ciclo de recuperaci´on esperables en funci´on del fluido de trabajo utilizado. La finalidad de este trabajo ha sido doble. Por un lado, debe servir como contribuci´on sobre estudios te´oricos de ciclos Rankine como sistemas de recuperaci´on, y por otro lado, como estudios preliminares para la instalaci´on experimental de un ciclo de recuperaci´on en un banco de ensayo, que ha permitido comparar las prestaciones reales con las obtenidas te´oricamente para la realizaci´on de mejoras. En la realizaci´on del trabajo experimental del ciclo Rankine, se ha dise˜nado y construido una instalaci´on experimental acoplada a un motor de gasolina. Los estudios experimentales, en los cuales se ha basado la evaluaci´on de la potencialidad del ciclo, se han basado en estudios de puntos de funcionamiento m´as frecuentes en este tipo de motores, considerando condiciones estacionarias. El objetivo de los trabajos experimentales ha sido estudiar los efectos de la implementaci´on de sistemas de recuperaci´on de energ´ıa t´ermica residual en el veh´ıculo, y en consecuencia, cuantificar el efecto del mismo en la eficiencia global del motor. / Sánchez Serrano, J. (2015). Contribución a la implementación de Ciclos Rankine como sistema de aprovechamiento de energía térmica residual en MCIA [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48564 / TESIS