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Apeldoorn, Netherlands

Velthof G.L.,Wageningen University | van Bruggen C.,Statistics Netherlands CBS | Groenestein C.M.,Wageningen UR Livestock Research | de Haan B.J.,PBL Netherlands Environmental Assessment Agency | And 2 more authors.
Atmospheric Environment | Year: 2012

Agriculture is the major source of ammonia (NH3). Methodologies are needed to quantify national NH3 emissions and to identify the most effective options to mitigate NH3 emissions. Generally, NH3 emissions from agriculture are quantified using a nitrogen (N) flow approach, in which the NH3 emission is calculated from the N flows and NH3 emission factors. Because of the direct dependency between NH3 volatilization and Total Ammoniacal N (TAN; ammonium-N + N compounds readily broken down to ammonium) an approach based on TAN is preferred to calculate NH3 emission instead of an approach based on total N. A TAN-based NH3-inventory model was developed, called NEMA (National Emission Model for Ammonia). The total N excretion and the fraction of TAN in the excreted N are calculated from the feed composition and N digestibility of the components. TAN-based emission factors were derived or updated for housing systems, manure storage outside housing, manure application techniques, N fertilizer types, and grazing. The NEMA results show that the total NH3 emission from agriculture in the Netherlands in 2009 was 88.8 Gg NH3-N, of which 50% from housing, 37% from manure application, 9% from mineral N fertilizer, 3% from outside manure storage, and 1% from grazing. Cattle farming was the dominant source of NH3 in the Netherlands (about 50% of the total NH3 emission). The NH3 emission expressed as percentage of the excreted N was 22% of the excreted N for poultry, 20% for pigs, 15% for cattle, and 12% for other livestock, which is mainly related to differences in emissions from housing systems. The calculated ammonia emission was most sensitive to changes in the fraction of TAN in the excreted manure and to the emission factor of manure application. From 2011, NEMA will be used as official methodology to calculate the national NH3 emission from agriculture in the Netherlands. © 2011 Elsevier Ltd. Source


Tonini A.,LEI | Pede V.,International Rice Research Institute
Entropy | Year: 2011

In this paper, a stochastic frontier model accounting for spatial dependency is developed using generalized maximum entropy estimation. An application is made for measuring total factor productivity in European agriculture. The empirical results show that agricultural productivity growth in Europe is driven by upward movements of technology over time through technological developments. Results are then compared for a situation in which spatial dependency in the technical inefficiency effects is not accounted. © 2011 by the authors. Source


Bracke M.B.M.,Researcher of animal welfare | Bracke M.B.M.,Wageningen UR Livestock Research | De Lauwere C.C.,LEI | Wind S.M.M.,Wageningen UR Livestock Research | Zonerland J.J.,Wageningen UR Livestock Research
Journal of Agricultural and Environmental Ethics | Year: 2013

The Dutch policy objective of a fully sustainable livestock sector without mutilations by 2023 is not compatible with the routine practice of tail docking to minimize the risk of tail biting. To examine farmer attitudes towards docking, a telephone survey was conducted among 487 conventional and 33 organic Dutch pig farmers. "Biting" (of tails, ears, or limbs) was identified by the farmers as a main welfare problem in pig farming. About half of the farmers reported to have no tail biting problems in their own herd. When farmers did report problems, they most often reported figures between 1 and 5 % of the animals. High incidences of tail biting were anticipated when trying to keep undocked pigs. Enrichment materials used in the conventional sector included mainly chains (52-63 % of the farms) and hanging rubber or plastic balls (22-30 %). Straw, sawdust, or wood shavings was hardly provided in conventional pig farming (2-3 %), in contrast to organic farming (88-100 % of farms). Conventional pig farmers feel a curly tail is not very important for sustainable pig farming. They consider enrichment to be less effective and tail docking to be less stressful for them and their piglets than their organic colleagues do. Pig farmers identified climate as a main risk factor for tail biting as opposed to enrichment. The objective of reducing routine tail docking requires solutions for dealing with tail biting problems at the farm level. In this process, transfer of scientific knowledge about enrichment materials and other measures to prevent and cure tail biting is critical, as is a change in farmer attitudes and awareness of the moral issues involved. © 2012 The Author(s). Source


de Vos B.I.,LEI | de Vos B.I.,Wageningen University | van Tatenhove J.P.M.,Wageningen University
Marine Policy | Year: 2011

Until the 1990s fisheries were largely managed by the state. Since then, Dutch government and the sector increasingly recognized that a fishing industry cannot be managed effectively without the cooperation and participation of fishers to formulate policy and to implement and enforce laws and regulations. As a result, in the nineties, the existing neo-corporatist arrangement was replaced by a co-management system in the Dutch flatfish fishery. Co-management is often seen as leading to greater procedural legitimacy and subsequently compliance. However, constructing an effective co-management arrangement is not only a matter of building institutions but also a matter of building trust relations between the government and industry. Institutional arrangements such as co-management can contribute to these trust building processes; however, a too strong reliance on institutional arrangements can lead to distrust when new challenges are being faced and institutional arrangements fail to adapt to these changes. © 2010 Elsevier Ltd. Source


Dongiovanni D.N.,Safety Technologies | Iesmantas T.,LEI
Fusion Engineering and Design | Year: 2016

Availability will play an important role in the Demonstration Power Plant (DEMO) success from an economic and safety perspective. Availability performance is commonly assessed by Reliability Availability Maintainability Inspectability (RAMI) analysis, strongly relying on the accurate definition of system components failure modes (FM) and failure rates (FR). Little component experience is available in fusion application, therefore requiring the adaptation of literature FR to fusion plant operating conditions, which may differ in several aspects. As a possible solution to this problem, a new methodology to extrapolate/estimate components failure rate under different operating conditions is presented. The DEMO Balance of Plant nuclear steam turbine component operated in pulse mode is considered as study case. The methodology moves from the definition of a fault tree taking into account failure modes possibly enhanced by pulsed operation. The fault tree is then translated into a Bayesian network. A statistical model for the turbine system failure rate in terms of subcomponents' FR is hence obtained, allowing for sensitivity analyses on the structured mixture of literature and unknown FR data for which plausible value intervals are investigated to assess their impact on the whole turbine system FR. Finally, the impact of resulting turbine system FR on plant availability is assessed exploiting a Reliability Block Diagram (RBD) model for a typical secondary cooling system implementing a Rankine cycle. Mean inherent availability for a period of 20 years plant mission range from 79% to 82% when varying turbine subcomponents FR from 1E-4/h to 1E-8/h, respectively, and much lower than the 97% performance expected for steady state operation. © 2016. Source

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