Comparisons of luminaires: Efficacies and system design

Lighting designs for architectural (aesthetic) purposes, vision and safety, and plant growth have many features in common but several crucial ones that are not. The human eye is very sensitive to the color (wavelength) of light, whereas plants are less so. There are morphological reactions, particularly to the red and blue portions of the light spectrum but, in general, plants appear to accept and use light for photosynthesis everywhere over the PAR region of the spectrum. In contrast, the human eye interprets light intensity on a logarithmic scale, making people insensitive to significant differences of light intensity. As a rough rule, light intensity must change by 30 to 50% for the human eye to recognize the difference. Plants respond much more linearly to light energy, at least at intensities below photosynthetic saturation. Thus, intensity differences not noticeable to the human eye can have significant effects on total plant growth and yield, and crop timing. These factors make luminaire selection and lighting system design particularly important when designing supplemental lighting systems for plant growth. Supplemental lighting for plant growth on the scale of commercial greenhouses is a relatively expensive undertaking. Light intensities are often much higher than required for task (vision) lighting, which increases both installation and operating costs. However, and especially in the northern regions of the United States (and Canada, Europe, etc.), supplemental lighting during winter may be necessary to produce certain crops (e.g., tomatoes) and very useful to achieve full plant growth potential and crop timing with most other greenhouse crops. Operating costs over the life of a luminaire typically will exceed the initial investment, making lighting efficacy a major consideration. This report reviews tests completed to evaluate the efficiencies of various commercially-available High-Pressure Sodium luminaires, and then describes the results of using a commercial lighting design computer program, Lumen-Micro, to explore how to place luminaires within greenhouses and plant growth chambers to achieve light (PAR) uniformity and relatively high lighting efficacies. Several suggestions are presented which could encourage systematic design of plant lighting systems

Escola ambiental: transferência de tecnologias geradas pela Embrapa para a segurança alimentar e a valorização da agricultura urbana nas escolas da cidade de Belém, Pará.

Organizar e qualificar os conhecimentos e tecnologias sobre educação ambiental, segurança alimentar, cultivo de hortas, formação de pomares e a criação de abelhas sem ferrão adaptáveis ao cultivo em escolas; Implantar módulos de cultivos de hortifrutigrangeiros, de pomares e de criação de abelhas sem ferrão para demonstração de tecnologias visando contribuir para a formação educacional sobre educação ambiental e segurança alimentar; Desenvolver ações de comunicação para disseminar as iniciativas e os resultados do projeto; Capacitar agentes multiplicadores (professores, funcionários, alunos, familiares de alunos e etc.) para desenvolvimento da agricultura urbana através de ação educativa e melhoria de hábitos alimentares; Monitorar e avaliar os resultados e impactos das ações de TT

Variational Approach to Hard Sphere Segregation Under Gravity

It is demonstrated that the minimization of the free energy functional for hard spheres and hard disks yields the result that excited granular materials under gravity segregate not only in the widely known "Brazil nut" fashion, i.e. with the larger particles rising to the top, but also in reverse "Brazil nut" fashion. Specifically, the local density approximation is used to investigate the crossover between the two types of segregation occurring in the liquid state, and the results are found to agree qualitatively with previously published results of simulation and of a simple model based on condensation.Comment: 10 pages, 3 figure

Energie- en klimaatmonitor agrosectoren 2011

Onderzoek van Agenschap NL en WUR-LEI in opdracht van het ministerie van Economische Zaken, Landbouw en Innovatie (EL&I). Uit de monitor blijkt dat de Nederandse land- en tuinbouwbedrijven meer elektriciteit produceren dan ze zelf verbruiken. De totale bijdrage van deze sectoren aan de in Nederland gebruikte duurzame energie is 44 procent. Ruim de helft van het energieverbruik van de land- en tuinbouwbedrijven zelf (uitgezonderd de glastuinbouw) is afkomstig uit hernieuwbare bronnen

Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations

The research leading to these results has received funding from the European Union's Horizon 2020 Programme under the ESTiMatE project, grant agreement No. 821418. The authors thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (IM-2020-3-0022, IM-2021-1-0016).García-Oliver, JM.; Pastor Enguídanos, JM.; Olmeda-Ramiro, I.; Both, A.; Mira, D. (2022). Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations. 690-699. http://hdl.handle.net/10251/19067769069

Surface Instability in Windblown Sand

We investigate the formation of ripples on the surface of windblown sand based on the one-dimensional model of Nishimori and Ouchi [Phys. Rev. Lett. 71, 197 (1993)], which contains the processes of saltation and grain relaxation. We carry out a nonlinear analysis to determine the propagation speed of the restabilized ripple patterns, and the amplitudes and phases of their first, second, and third harmonics. The agreement between the theory and our numerical simulations is excellent near the onset of instability. We also determine the Eckhaus boundary, outside which the steady ripple patterns are unstable.Comment: 23 pages, 8 figure

Migration route, stopping sites, and non-breeding destinations of adult Black-tailed Godwits breeding in southwest Fryslân, The Netherlands

In this paper, we extend our understanding of the migration of Black-tailed Godwits (Limosa limosa limosa) by describing: (1) the orientation and geographic locations of individual migratory routes and (2) the spatial distribution of godwits across seasons and years. We accomplish this using satellite-tracking data from 36 adult godwits breeding in the 200-ha Haanmeer polder in The Netherlands, from 2015 to 2018. During both southward and northward migration, godwits used a narrow migratory corridor along which most individuals made stops within a network of sites, especially the Bay of Biscay, France and Doñana, Spain. Most sites were used consistently by the same individuals across years. However, sites in Morocco were used during northward migration by 75% of individuals, but not revisited by the same individual across years. After southward migration, a small proportion (15%) of godwits spent the entire non-breeding period north of the Sahara, but most (85%) crossed the Sahara and spent at least part of the non-breeding season among seven coastal sites in West Africa and one site in the Inner Niger Delta. Although site-use patterns varied among individuals, individuals showed high site fidelity and were consistent in the number of sites they used from year to year. The considerable differences in the spatial distribution of individuals that breed within a kilometre of one another raise questions about the causes and consequences of individual migratory differences. We discuss that full annual cycle tracking of juveniles from birth to adulthood is needed to understand the source of these individual differences. Our results on the spatial distribution of godwits throughout their annual cycle lay an important foundation of information that can be used to help conserve this declining species

Emergency care provided to refugee children in Europe: RefuNET: A cross-sectional survey study

Background Refugee children and young people have complex healthcare needs. However, issues related to acute healthcare provision for refugee children across Europe remain unexplored. This study aimed to describe the urgent and emergency healthcare needs of refugee children in Europe, and to identify obstacles to providing this care.Methods An online cross-sectional survey was distributed to European healthcare professionals via research networks between 1 February and 1 October 2017 addressing health issues of children and young people age

Translocation as a Novel Approach to Study Effects of a New Breeding Habitat on Reproductive Output in Wild Birds

Environmental conditions under which species reproduce have major consequences on breeding success and subsequent fitness. Therefore breeding habitat choice is ultimately important. Studies rarely address the potential fitness pay-offs of alternative natural breeding habitats by experimental translocation. Here we present a new tool to study fitness consequences of free living birds in different habitats. We translocated a migratory passerine, the pied flycatcher (Ficedula hypoleuca), to a novel site, where pairs were subjected to a short stay (2–4 days) in a nest box-equipped aviary before being released. We show that it is technically possible to retain birds in the new area for breeding, allowing the study of reproductive consequences of dispersal under natural conditions. The translocation resulted in an extension of the interval between arrival and egg laying of four days, highlighting the importance of having an adequate control group. Clutch size and nestling parameters did not differ significantly between translocated and unmanipulated females, which suggests that the procedure did not affect birds in their reproductive performance later on. This method could be applied broadly in evolutionary and ecological research, e.g., to study the potential fitness benefits and costs for dispersing to more northern latitudes as a way of adapting to climate change

The importance of post marketing quality control

BACKGROUND A previously published study reported on the nonlinear behaviour for airway pressure and tidal volume of the adjustable pressure-limiting (APL) valve of the Aisys CS2 anaesthesia machine (GE Healthcare, Madison, Wisconsin, USA) during manual bag ventilation. In co-operation with the manufacturer, an adapted APL valve was developed. OBJECTIVE To test and characterise the performance of an adapted APL valve and assess its clinical usability. DESIGN Two-stage study, consisting of an in-vitro testing of an adapted APL valve in a baby and adolescent lung model, followed by a clinical experience survey of anaesthesia personnel after the official implementation of the new APL valve into clinical routine. SETTING Anaesthesia Department at the University Children's Hospital Zurich. MAIN OUTCOME MEASURES Airway pressures and inspiratory tidal volumes during opening and closure of the APL valve at different settings. Likert scale assessment of performance expectance, effort expectance, behavioural intention and safety of the APL valve during clinical use. RESULTS In contrast to the original APL valve of the GE Aisys CS2, the adapted APL valve showed a nearly linear increase in airway pressures as well as in the tidal volumes measured. Most importantly, the measured pressures never exceeded the set pressures. Based on the experimental findings, all original APL valves of the GE Aisys CS2 were replaced by the adapted APL valve. Two months later, an anonymised and standardised questionnaire was handed out to all employees working with the adapted APL valve. Analysis of the questionnaire indicated that the adapted APL valve is easier and more precise to handle in the daily routine than the original one. CONCLUSION The newly adapted APL valve for the GE Aisys CS2 has considerably improved its linearity at lower pressures and supports our institution's bag mask ventilation practices