100,594 research outputs found
Structures of feeling
No full textTim Verlaan opens a new perspective on the politics of urban redevelopment in Western European cities by investigating different notions of which urban structures should represent a democratic society at the tail end of the postwar economic boom. Specifically, the chapter examines how technocratic private developers collided with action groups over Hoog Catharijne, a vast office and shopping complex in the Dutch city of Utrecht. As an architectural antidote to this consumers’ paradise, the action groups advocated plans for a cultural venue. By researching the developers’ company records and local council archives, Verlaan investigates emotions attached to urban spaces together with notions of democracy and citizenship. As both development schemes aimed at enlightening Dutch citizens, this conflictual entanglement of consumerism and culture points to the adversarial history of subject formation. The different appeals to subjectivity translated into ways in which both schemes connected to the surrounding urban fabric and a new urban vocabulary
The magic centre:The Provo movement and sociocultural critiques on urban redevelopment in Amsterdam 1965-1970
Get PDFWhat bonded the opponents of urban redevelopment in post-war Amsterdam was their aversion to the agenda’s detrimental side-effects, whether these concerned the social impacts of population displacement, increasing pollution or the demolition of historical structures. One of the first and most influential urban social movements to bring these critiques together was Provo, a motley crew of mostly young protesters from all walks of life. The first aim of this chapter is to determine how their call for the right to the city was translated into the representation and transformation of urban space. The arrival of a younger generation of urbanites and the indelible mark they left on the city’s cultural scene is researched in tandem, resulting in a new reading of urban modernity. The second aim is to identify the members of Amsterdam’s urban social movements, Provo in particular, and their alliances with political, cultural and media institutions. As will be shown, Provo’s cultural politics were largely aimed at visualizing and politicizing the negative consequences of urban redevelopment. Bringing theories on social movements and urban space together, this contribution offers a more comprehensive and multifaceted narrative of the emergence of Provo and similar urban social movements, focusing in particular on the culture wars they waged on Amsterdam’s political establishment
Modelling and characterization of an airlift-loop bioreactor
No full textAn airlift-loop reactor is a bioreactor for aerobic biotechnological processes. The special feature of the ALR is the recirculation of the liquid through a downcomer connecting the top and the bottom of the main bubbling section. Due to the high circulation-flow rate, efficient mixing and oxygen transfer is combined with a controlled liquid flow in the absence of mechanical agitators.Liquid velocities and gas hold-ups in an external-loop airlift reactor (ALR) on different scales were modelled on the basis of a simple pressure balance. The model is adapted for non-isobaric conditions and takes into account nonuniform flow profiles and gas hold-up distributions across the duct. The friction coefficient together with the reactor dimensions are input parameters. It has been shown that the friction coefficient can be obtained from simple one-phase flow calculations based on known data of the seperate reactor parts. The model predicts liquid velocities and local gas hold-ups in an ALR to within 10% and can be applied easily to an internal loop reactor.Mixing in the individual sections of the ALR is determined by a newly developed parameter estimation procedure which has proven to be reliable for the estimation of axial dispersion coefficients in the individual sections of the ALR. From the results it can be concluded, that in an ALR the liquid flow behaves like plug-flow with superimposed dispersion except for the topsection for which it is not reasonable to assume plug-flow. The mixing results simplified the modelling of oxygen transfer in the ALR as it appeared not to be necessary to incorporate the dispersion contribution Into the oxygen model.The non-isobaric plug-flow model, presented in this thesis, predicts dynamic and stationary dissolved oxygen concentration (DOC) profiles in large-scale ALRs and has been applied also to estimate the volumetric oxygen transfer coefficient, k 1 a, in the pertinent ALR. Comparison with the results on the basis of a simple isobaric stirred-tank-reactor model demonstrates, that such a model yields conservative values though for the present situation the underestimation did not exceed a value of 10% relative to the plug-flow model. Therefore, due to its simplicity, it is recommended to use the stirred tank model for a rapid characterization of the overall aeration capacity of laboratory scale and pilot-scale ALRs. Oxygen depletion of the gas phase, even during a fermentation, appeared to be very limited and was fairly well predicted by the plug-flow model. For this reason an ALR is a very suitable reactor for aerobic processes having a high oxygen demand. If necessary, the aeration capacity of the ALR can be enhanced by injection of a small amount of gas at the entrance of the downflow region. This phenomenom is also accurately predicted by the plug-flow model. In the present ALR the aeration capacity of the air-sparger region did not significantly differ from the main aeration process in the upflow region due to its special geometry.The intermediate flow region between the ALR and the bubble-column (BC) flow regime was investigated by gradually closing a butterfly valve at the bottom of the downcomer. When the valve is further shut and thus the friction is enhanced, the liquid velocity will be reduced thereby enlarging the gas hold-up. The maximum value for the gas hold-up is obtained when the ALR is operated as a BC. In the transition flow regime between ALR and BC flow, the liquid velocity was found to be a simple power law function of the gas flow rate. The coefficients of the power law depend on the flow characteristics in the reactor. In the transition flow regime the hydrodynamic calculations based on the plug-flow behaviour of an ALR are only valid up to a certain defined value of the total gas-liquid flow rate. For greater values, the ALR type of flow will change Into a BC type of flow. A simple criterium qualifies the distinction between both flow patterns, determined by the superficial liquid velocity and the liquid circulation velocity.The transition of ALR to BC flow coincides with the decrease of the Bodenstein number which also indicates a less established plug flow. As the dispersion coefficient at a constant gas-flow rate, remained constant for as well the ALR, the BC and the transition flow, the decreased Bodenstein number in the BC-type of flow is mainly attributed to the decreased convective transport as the liquid circulation is impeded. The number of circulations required to achieve complete mixing diminshes when the liquid circulation is impeded and appeared to be proportional to the Bodenstein number.In the transition flow regime, the volumetric oxygen transfer coefficient was estimated by both the stirred-tank model and the plug-flow model. The stirred-tank model yielded reliable results for the entire range of operation while the plug-flow model only appeared to be appropiate for the ALR operation mode. The volumetric oxygen transfer coefficient was found to increase for the BC operation mode and appeared to be a power law function of the ratio of the superficial liquid and gas velocity and the Bodenstein number.Addition of immobilized biocatalysts to the ALR, in our case simulated by neutral buoyant particles with diameters ranging from 2.4-2.7 am, significantly reduces the liquid velocity and the gas hold-up in an ALR. The decrease in liquid velocity is attributed to the decrease in gas hold-up and an increased friction in the ALR. The gas hold-up is reduced mainly because the presence of the particles increases the collision frequency of the air bubbles thereby increasing coalescence due to the diminished flowed area available for the air-water mixture. In comparison to a gas-liquid flow, axial dispersion in the three-phase flow is reduced as the presence of the particles damps the small eddies which are, apart from other mechanisms, responsible for the axial dispersion. Moreover. the increased coalescence also contributes to a decrease in axial dispersion. The presence of the particles negatively influences aeration due to a reduction in the gas-liquid interfacial area as a result of the increased coalescence. The effect of the increase in apparent viscosity in the ALR was not supposed to contribute to the decrease in the aeration process
Introduction:Urban activism in Western European cities from the 1950s to the 1980s
Get PDFThe first part of this chapter introduces key concepts relevant for a history of urban activism, and sheds light on developments relevant to the problem of historicising urban (social) movements during the ‘long 1970s’, when a convergence of ideological and economic changes coalesced with the social and spatial consequences of the urban crisis. The second part of the chapter sketches the content of the volume and introduces each chapter separately
Structures of Feeling: Urban redevelopment as self-development in Dutch postwar architecture
No full textTim Verlaan opens a new perspective on the politics of urban redevelopment in Western European cities by investigating different notions of which urban structures should represent a democratic society at the tail end of the postwar economic boom. Specifically, the chapter examines how technocratic private developers collided with action groups over Hoog Catharijne, a vast office and shopping complex in the Dutch city of Utrecht. As an architectural antidote to this consumers’ paradise, the action groups advocated plans for a cultural venue. By researching the developers’ company records and local council archives, Verlaan investigates emotions attached to urban spaces together with notions of democracy and citizenship. As both development schemes aimed at enlightening Dutch citizens, this conflictual entanglement of consumerism and culture points to the adversarial history of subject formation. The different appeals to subjectivity translated into ways in which both schemes connected to the surrounding urban fabric and a new urban vocabulary
De ruimtemakers: Projectontwikkelaars en de Nederlandse binnenstad 1950-1980
No full textNederlandse binnensteden stonden in de jaren vijftig en zestig voor een enorme opgave. De naoorlogse welvaartsgroei leidde tot een explosieve toename van het aantal auto’s en een snelgroeiende vraag naar moderne kantoor- en winkelruimte. Wilden lokale bestuurders hun binnensteden klaarstomen voor het magische jaar 2000, dan moesten zij met spoed ruimte gaan maken. Projectontwikkelaars gaven met plannen als het Utrechtse Hoog Catharijne een daadkrachtig antwoord op de vraag hoe de binnenstad van de toekomst vorm en inhoud moest krijgen. Het zou echter niet lang duren voordat burgers in verzet kwamen tegen hun visioenen, waardoor in de jaren zeventig een onstuimige discussie op gang kwam. In De ruimtemakers onderzoekt Tim Verlaan de geschiedenis van dit conflict. Voor het eerst staan hierbij de visies van flamboyante projectontwikkelaars en machtige bouwondernemingen centraal. Hoe en waarom wilden bestuurders met hen samenwerken, en waarom botsten zij uiteindelijk met burgers? Het gebruik van nieuw bronnenmateriaal leidt tot verrassende inzichten. Zo was Hoog Catharijne niet altijd de lelijkste plek van Nederland, zijn vastgoedschandalen van alle tijden, en kunnen we de toenemende druk op de stedelijke woningmarkt verklaren uit het succes van radicale actiegroepen
Policy analysis for improving performance of PPP projects in Vietnam: A Case Study from BOT Phu My Bridge Project
No full textThe important of PPP model to the development of infrastructure as well as the Vietnamese economy, and exiting obstacles in BOT practices in Vietnam inspire me to do this thesis. Among many critical success factors influencing to performance of BOT practice in Vietnam, the author recognizes that Vietnamese government should try all its efforts to improve the financial market, ability to mange risks, legislation and regulation to leverage private involvement in BOT scheme. The other factors can be achieved by the learning curve process on the course of local and international PPP practice. Thus, the thesis focuses on PPP model specializing in the following main aspects: (1) financing of PPP projects, (2) management of risks in PPP projects, (3) the institutional and legal framework of PPP projects.Construction Management and EngineeringBouwCivil Engineering and Geoscience
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
Get PDFIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
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