164 research outputs found

    Experimentation or projectification of urban change?:A critical appraisal and three steps forward

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    Urban experimentation has proliferated in recent years as a response to sustainability challenges and renewed pressures on urban governance. In many European cities, diverse and rapidly changing experimental forms (e.g. urban living laboratories, pilots, trials, experimental districts) are becoming commonplace, addressing ambitious goals for smartness, circularity, and liveability. Academically, there is a growing concern for moving beyond the focus on individual experiments and the insistence on upscaling their primary transformation mechanism. However, the phenomena of 'projectification' - whereby project-based forms of organising have become ubiquitous, shaping expectations about experimentation - is increasingly perceived as a barrier. Nevertheless, how specifically experimentation and projectification intersect remains unclear. Our theoretical perspective examines how the widespread tendency towards projectification shapes urban experimentation and the potential implications for urban transformations. It problematises the current wave of experimentation and how it contributes to the projectification of urban change processes. We present three steps to redress this issue and indicate directions for future research.</p

    Prediction of the radial solids concentration distribution in circulating fluidized bed risers

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    The presented work deals with the development of a model for the prediction of the radial solids concentration distribution in circulating fluidized bed risers. In order to provide a substantial basis for the model development, non‑invasive investigations on the solids distribution over the cross-section of a pilot plant scale circulating fluidized bed riser are carried out using X‑ray computed tomography. The examined operating range covers cross-section averaged solids concentrations between 2.7 vol.% and 38.1 vol.% while superficial gas velocities were adjusted in the range from 0.4 m s‑1 up to 6.0 m s‑1. Especially in the case of dense gas‑solid flow conditions detrimental beam hardening effects gain influence, distorting the results of the X-ray measurements (1). Thus, a novel calibration method is presented to facilitate the derivation of volumetric solids concentrations from the measured tomographic attenuation data. In this, an emphasized feature consists in the elimination of low energetic radiation from the incident X‑ray spectrum to avoid beam hardening effects, which are caused by the pipe material and the fluidized solids. Evaluation of the presented technique by comparison of the derived cross-section averaged solids concentrations with those obtained from differential pressure measurements confirms its high accuracy. Subsequently, the technique is applied for quantitative analysis of the radial solids concentration distribution in a gas‑solid circulating fluidized bed riser in dependence of the overall solids holdup and the superficial gas velocity. The high spatial resolution and the non-invasive character of the applied technique allow for detailed examination of the solids concentration prevailing in close proximity of the inner riser wall as well as in the center of the cross-section. The tomographic X‑ray scans of the cross-section of the riser, operated under dilute and highly dense conditions, provide a comprehensive set of measurement data, based on which a model is developed that allows for the prediction of the radial solids concentration distribution in vertical gas-solid upflow. The proposed model is found to reliably predict the radial solids concentration distribution under dilute as well as under dense flow conditions. Please click Additional Files below to see the full abstract

    Comparison of ozonated water and acidified copper sulphate in prevention of digital dermatitis in dairy cows

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    Digital dermatitis (DD) is the most significant infectious hoof disorder of cattle in Europe. Hoof baths are one of the most common control methods. Copper sulphate and formalin are commonly used in hoof baths, but their use is problematic in many European countries for health, environmental and safety reasons. Ozonated water and acidified copper sulphate were tested as prevention of DD in a 5-month study. Data were derived from 302 hind feet of Holstein and Estonian Red cows (no. of cows = 151) from a commercial dairy farm in Estonia. Altogether 168 hind feet were included in the acidified copper sulphate group and 134 feet in the ozonated water group. Hoof bathing was carried out three days a week (Mon, Wed, Fri) for two months and then two days a week (Mon, Wed) for three and a half months, in both groups. Ozonated water was sprayed on to the digital skin of hind feet of cows twice a day on treatment days, while the cows were eating. The copper sulphate bath consisted of copper sulphate (2%) mixed with an organic acid compound to acidify and ionize the solution. Cows walked through acidified copper sulphate solution twice a day on treatment days as they were exiting the milking parlor. DD negative and DD positive test results in both groups were compared and statistically tested for differences. The copper sulphate solution was more effective than ozonated water at preventing acute DD lesions. A random maximum likelihood model demonstrated that the odds ratio for DD in the ozonated water group was six times higher compared with DD in the acidified copper sulphate group. Most of the cows that were initially without any DD lesions (M0 + no other severe hoof lesion), remained lesion-free in both groups (copper sulphate group 97% and ozonated water group 88%). Despite trial design deficiencies, the findings indicate that acidified copper sulphate was a more effective solution in preventing DD than ozonated water.Peer reviewe

    Intracavity Raman scattering couples soliton molecules with terahertz phonons

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    Ultrafast atomic vibrations mediate heat transport, serve as fingerprints for chemical bonds and drive phase transitions in condensed matter systems. Light pulses shorter than the atomic oscillation period can not only probe, but even stimulate and control collective excitations. In general, such interactions are performed with free-propagating pulses. Here, we demonstrate intra-cavity excitation and time-domain sampling of coherent optical phonons inside an active laser oscillator. Employing real-time spectral interferometry, we reveal that Terahertz beats of Raman-active optical phonons are the origin of soliton bound-states – also termed “Soliton molecules” – and we resolve a coherent coupling mechanism of phonon and intra-cavity soliton motion. Concurring electronic and nuclear refractive nonlinearities generate distinct soliton trajectories and, effectively, enhance the time-domain Raman signal. We utilize the intrinsic soliton motion to automatically perform highspeed Raman spectroscopy of the intra-cavity crystal. Our results pinpoint the impact of Raman-induced soliton interactions in crystalline laser media and microresonators, and offer unique perspectives toward ultrafast nonlinear phononics by exploiting the coupling of atomic motion and solitons inside a cavity

    The nexus of business sustainability and organizational learning: A systematic literature review to identify key learning principles for business transformation

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    Companies play a central role in the quest for sustainable development. Organizational learning theories have been utilized to explain sustainability-related change processes in firms. However, implications from studies at the nexus of business sustainability and organizational learning are highly dependent on varying conceptualizations. The objective of this study is to provide clarity on the plurality of conceptual underpinnings in research and to uncover principles that are associated with deeper organizational change processes, that is, business transformation. Building on insights from a systematic literature review, we develop a sustainability learning typology, from which we distill three learning principles for business transformation: (1) the deutero learning mode, (2) the societal learning scope, and (3) the cooperative advantage objective. We formulate needs for future research to further elaborate on the learning principles associated with business transformation and suggest implications for practice

    Transformative innovation and translocal diffusion

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    This paper develops a conceptual understanding of transformative innovations as shared activities, ideas and objects across locally rooted sustainability initiatives that explore and develop alternatives to incumbent and (perceived) unsustainable regimes that they seek to challenge, alter or replace. We synthesize empirical work from two European research projects (TRANSIT and ARTS), in which initiatives and networks were empirically studied, to develop a broader conceptual understanding of the emergence of transformative innovation. The development of initiatives can occur through growing, replicating, partnering, instrumentalising and embedding. This is supported through translocal networks that connect initiatives by sharing ideas, objects and activities across local contexts. This translocal characteristic of transformative innovations harnesses an enormous potential for sustainability transitions, but requires further understanding a

    Transformation gestalten : warum die Dekade des Handelns neues Lernen erfordert

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    Zur Gestaltung von tiefgreifenden Transformationsprozessen fehlen oft handlungsleitende Kompetenzen und der Mut, Strukturen aufzubrechen. Dafür braucht es andere Lernformen und neue Räume des Lernens für nachhaltigen Wandel. Um solche zu etablieren, haben die Vereinten Nationen die Dekade des Handelns ausgerufen, in deren Rahmen zwei Projekte des Wuppertal Instituts gestartet sind: die Transformationsakademie und HumboldtN

    The effect of consumer scepticism on the perceived value of a sustainable hotel booking

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    Tourists find it hard to evaluate the advantages of a sustainable hotel and others may be even sceptical about sustainable tourism altogether. The study reported here was designed to investigate the associations between perceived benefits, perceived costs, and perceived value while booking a sustainable hotel. In addition, the moderating role of scepticism is assessed relating the paths linking the study variables. The study is based on an online survey carried out with1056 respondents in the USA. The results of structural equation modeling indicate that the perceived benefits, both authentic and environmental benefits were significantly influencing perceived value; and perceived value had a significant influence on booking intentions. The moderating effect of scepticism on authentic benefit perceptions with perceived value suggests that when respondents are sceptical about sustainability in general, it alters the relationship between authentic benefit perceptions and perceived value showing a negative impact. The study provides implications for sustainable hotel marketing by emphasising the need to understand how potential consumers perceive the sustainable product value and how this affects their booking intentions
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