Expanding the exergy concept to the urban water cycle

The world is urbanizing fast and this increases the pressure on available resources. In a world of cities, it is therefore crucial to take a new look at the way urban systems function: where do the resources come from and where do the wastes end up? It is essential to find ways to minimize urban impacts on resource depletion and environmental impacts and also to improve cycles within the systems. Energy and water cycles are vital to support urban life. Over the last decades, important advances have been made separately in the field of integrated water management and energy efficiency in urban areas. However, for urban planning purposes a shared framework is required that allows planners to model and understand the dynamics of the broader system to achieve an integrated management of the resources. Natural energy and water cycles are modified by metabolic profiles of the cities. The metabolic profile varies with the local resource availability and the level of technological development. To cope with this complexity, the concept of Exergy, based on Thermodynamic laws, and defined as the non-used fraction of energy, has been used to understand the energy cycle in the built environment. This will lead to new approaches towards urban planning and better resources use. This paper aims to find out if the exergy concept can be expanded to the water cycle defined as the use of the non-used water(-fraction). This way the cycle can be optimized and closed at a high efficiency level. In order to achieve this, we want to study to what extend the energy and water cycles are comparable, and how they can learn from each other in order to optimize their management

Beetle eater beheerst de aspergekever bij de oogst van groene asperges in 2010

In Canada is een grote stofzuiger die voor of achter een tractor bevestigd kan worden “Beetle Eater” genaamd, gebruikt ter bestrijding van de coloradokever in aardappelen. Biologische telers hebben zo’n apparaat gekocht om hem in te zetten ter bestrijding van de wortelvlieg in peen. De resultaten vielen tegen en het apparaat is na twee jaar experimenteren niet meer gebruikt. In 2010 is de machine getest in groene asperges tegen de aspergekever op een gangbaar bedrijf in Noord - Brabant. Omdat groene asperges bij gunstige weersomstandigheden dagelijks geoogst worden, is het lastig om tegen dit insect gewasbeschermingsmiddelen in te zetten vanwege de veiligheidstermijn. Door de Beetle eater 1 of 2 keer (direct na elkaar) in te zetten worden de aspergekevers met 50 of 74% gereduceerd. De asperge oogsters merkten meteen wanneer de machine was ingezet omdat het aantal eitjes op de aspergestengels duidelijk afnam. Door de Beetle eater regelmatig in te zetten bleven het aantal afgezette eitjes op de stengels beperkt en zijn het gehele seizoen geen groene asperges bij deze teler afgekeurd en geen asperges daardoor aangemerkt als kwaliteit II. Een aandachtspunt is wel dat na iedere behandeling aspergestengels afbreken. Dit komt enerzijds omdat de rijafstand niet correspondeerde met de zuigmonden van de Beetle eater (scheelde 5 cm) en anderzijds omdat bij oudere percelen de aspergestengels verder uit het hart van de rug kunnen groeien. Door de zuigmond aan te passen (verbreden en iets te vergroten) is de verwachting dat het afbreken van de stengels beperkt wordt

Innovative BIPV rooftops: development, realization, and monitoring of 2 BIPV field tests in the Netherlands

Building Integrated PV (BIPV) is seen as strategy to realize the EU target of Nearly Zero Energy Buildings (NZEB’s), while at the same time creating an aesthetically acceptable built environment. This in contrast with Building Added PV (BAPV) of which the result is often seen as aesthetically unwelcome additions to new and existing building. BIPV might have some negative aspects considering lifespan and PV output besides the aesthetical positive effect. In this research project two field tests are realized to investigate the negative aspects of different BIPV solutions, focusing on the effect of back-string cooling of PV modules on PV electricity output, relative humidity and lifespan. These aspects are seen as possible bottlenecks for large-scale acceptance of BIPV in society and the design, realization and monitoring of these field tests can contribute to an increased implementation of BIPV through improved BIPV solutions

Comparative performance assessment of four BIPV roof solutions in the Netherlands

A significant amount of global energy consumption takes place in the built environment, with as collateral effect CO2-related climate change. One of the strategies to realize a significant CO2 reduction is by integrating photovoltaic modules in the building envelope (BIPV). Disadvantages of BIPV include a possibly lower energy output and a possibly decreased life span due to the lack of optimal cooling of the PV modules. Currently, cooling of PV modules is usually realized by passive back-string ventilation, which is under strain when integration PV modules in the building envelope. In this study, a comparative field study of BIPV is conducted in the field lab ‘The District of Tomorrow’ to generate insight into BIPV efficiency as a function of back-string ventilation. This paper presents a selection of the monitoring results of the realized system, consisting of 24 PV modules in 4 segments with a total of 6000 Wp output with different amounts of back-string ventilation. The measurements indicate that in a moderate climate BIPV solutions without back-string ventilation result in increased operating temperatures, lower electricity output and condensation between PV modules and rooftop surface. To decrease relative humidity levels and operating temperatures to acceptable values, back-string ventilation is seen as an effective cooling medium in the presented field case

Bedrijfssystemen-onderzoek vollegrondsgroenten te Westmaas : evaluatie 1991 - 1995

Vergelijking bedrijfssystemen op proefbedrijf in de Hoekse Waar

The Potential Added Value of Novel Hearing Therapeutics: An Early Health Economic Model for Hearing Loss

OBJECTIVE: To construct an early health economic model to assess the potential added value of novel hearing therapeutics, compared with the current standard of care. We use idiopathic sudden sensorineural hearing loss (ISSNHL) as a case example, because it is a lead indication for several emerging hearing therapeutics. METHODS: A decision analytic model was developed to assess the costs and effects of using novel hearing therapeutics for patients with ISSNHL. This was compared to the current standard of care. Input data were derived from literature searches and expert opinion. The study adopted a healthcare perspective of the UK National Health Service. Four analyses were conducted: 1) headroom, 2) scenario, 3) threshold, 4) sensitivity. RESULTS: The decision analytic model showed that novel therapeutics for ISSNHL have potential value both in terms of improved patient outcomes, as well as incremental net monetary benefit (iNMB). The base case analysis revealed an iNMB of £39,032 for novel therapeutics compared with the current standard of care. Results of the threshold and scenario analysis revealed that age of treatment and severity of ISSNHL are major determinants of iNMB for novel therapeutics. CONCLUSION: This article describes the first health economic model for novel therapeutics for hearing loss; and shows that novel hearing therapeutics can be cost-effective under NICE's cost-effectiveness threshold, with considerable room for improvement in the current standard of care. Our model can be used to inform the development of cost-effective hearing therapeutics; and help decision makers decide which therapeutics represent value for money

Subgroup effects despite homogeneous heterogeneity test results

Background. Statistical tests of heterogeneity are very popular in meta-analyses, as heterogeneity might indicate subgroup effects. Lack of demonstrable statistical heterogeneity, however, might obscure clinical heterogeneity, meaning clinically relevant subgroup effects. Methods. A qualitative, visual method to explore the potential for subgroup effects was provided by a modification of the forest plot, i.e., adding a vertical axis indicating the proportion of a subgroup variable in the individual trials. Such a plot was used to assess the potential for clinically relevant subgroup effects and was illustrated by a clinical example on the effects of antibiotics in children with acute otitis media. Results. Statistical tests did not indicate heterogeneity in the meta-analysis on the effects of amoxicillin on acute otitis media (Q = 3.29, p = 0.51; I2 = 0%; T2 = 0). Nevertheless, in a modified forest plot, in which the individual trials were ordered by the proportion of children with bilateral otitis, a clear relation between bilaterality and treatment effects was observed (which was also found in an individual patient data meta-analysis of the included trials: p-value for interaction 0.021). Conclusions. A modification of the forest plot, by including an additional (vertical) axis indicating the proportion of a certain subgroup variable, is a qualitative, visual, and easy-to-interpret method to explore potential subgroup effects in studies included in meta-analyse

Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High-TcT_{c} Superconductors

Muon spin relaxation ($\mu$SR) measurements in high transverse magnetic fields ($\parallel \hat c$) revealed strong field-induced quasi-static magnetism in the underdoped and Eu doped (La,Sr)$_{2}$CuO$_{4}$ and La$_{1.875}$Ba$_{0.125}$CuO$_{4}$, existing well above $T_{c}$ and $T_{N}$. The susceptibility-counterpart of Cu spin polarization, derived from the muon spin relaxation rate, exhibits a divergent behavior towards $T \sim 25$ K. No field-induced magnetism was detected in overdoped La$_{1.81}$Sr$_{0.19}$CuO$_{4}$, optimally doped Bi2212, and Zn-doped YBa$_{2}$Cu$_{3}$O$_{7}$.Comment: 4 pages, 4 color figure

Muon Spin Relaxation and Susceptibility Studies of Pure and Doped Spin 1/2 Kagom\'{e}-like system (Cux_xZn1−x_{1-x})3_{3}V2_{2}O7_7(OH)2_{2} 2H2_2O

Muon spin relaxation ($\mu$SR) and magnetic susceptibility measurements have been performed on the pure and diluted spin 1/2 kagom\'{e} system (Cu$_x$Zn$_{1-x}$)$_{3}$V$_{2}$O$_7$(OH)$_{2}$ 2H$_2$O. In the pure $x=1$ system we found a slowing down of Cu spin fluctuations with decreasing temperature towards $T \sim 1$ K, followed by slow and nearly temperature-independent spin fluctuations persisting down to $T$ = 50 mK, indicative of quantum fluctuations. No indication of static spin freezing was detected in either of the pure ($x$=1.0) or diluted samples. The observed magnitude of fluctuating fields indicates that the slow spin fluctuations represent an intrinsic property of kagom\'e network rather than impurity spins.Comment: 4 pges, 4 color figures, Phys. Rev. Lett. in pres