De organische - stofhuishouding van grassportvelden

Aan de hand van gegevens uit de literatuur en uit eigen onderzoek wordt een kwalitatieve benadering gegeven voor de organische-stofhuishouding bij grassportvelden in de laag 0-5 cm. Hierbij is gebruik gemaakt van de door Kortleven (1963) ontwikkelde formules

Differential responses of Nile tilapia (Oreochromis niloticus) to fin clip wounding and related stress: perspectives

The debate around fish welfare is intensifying in The Netherlands. As a result, more research is carried out to enhance knowledge on fish welfare in aquaculture. Detailed information is lacking on how production procedures causing discomfort to the fish may affect welfare. That fish must perceive adversive stimuli follows from the fact that nociceptive mechanisms similar to those in mammals are present in fish. However, whether and how nociceptive stimuli are perceived or interpreted by a fish is a far more difficult question that requires significantly more effort from fundamental research, both neurophysiological and behavioural studies, than now available. The study presented in this report aimed to define selected readout for the acute response to a supposedly painful stimulus: a standardised tailfin clip to a common carp. In conclusion, we succeeded to demonstrate differential, stronger responses to a presumed painful stimulus than to the handling stress per se associated with the administration of the pain stimulus. These parameters will be the focus of future research within this welfare project

School timetabling problem under disturbances

School timetables are one or multiple times per year generated to assign class-teacher combinations to class rooms and timeslots. Post-publication disturbances such as absence of teachers typically pose a need for schedulers to rapidly implement some minor changes to avoid empty periods in the timetable. In this paper our aim is to define methods to efficiently solve the school timetabling problem under disturbances. We present three types of solution methods, namely a simple rule-of-thumb, a heuristic and an optimization approach. Exhaustive numerical experiments have been performed with data from five high schools in The Netherlands, each with their unique characteristics in number of classes, number of teachers and number of daily meetings. For each of the three methods we show advantages and disadvantages as well as the effects of resulting changes in the schedules.<br/

Aspects of agricultural use of potato starch waste water.

Disposal of potato starch process water (average N, P2O5, K2O contents, 390, 140, 700 mg/l) on the land results in a high degree of purification. Complete purification is obtained in sandy soils if the rates do not exceed 100 to 150 mm/year. To maintain favourable conditions for biological decomposition of the organic matter the dose should be less than the water storage capacity of the soil. Disposal of the annual amount between a number of sprinkling irrigations is therefore recommended. Application rates can be adjusted to plant nutrient requirements. Optimum adjustment leads to an average yearly application of 25 mm yearly for the normal cropping pattern of the Peat Colonies. If excess supply is accepted the average value can be increased to 60 mm without harmful effects. From a computerized model study of the effect of the utilization of this waste water on farm economic results, the applications of 50 and 100 mm gave the highest returns.[227.7]. (Abstract retrieved from CAB Abstracts by CABI’s permission

An Internet-Based Course And The Application Of Employment-Based Methods In Civil Engineering Projects

The paper addresses the question of how educational activities in civil engineering in the Netherlands can contribute to the application of employment-based programs in developing countries. National policy makers and international donor representatives acknowledge the various advantages of employment-based programs. However, for a number of reasons the implementation of such programs generally forms a severe bottleneck. Because of the limited number of implemented programs the employment-based methods have not been sufficiently tested and improved, which in turn inhibits reaching the full potential of the employmentbased policies. The University of Twente (UT) has developed a modest program to assist interested governmental and private organisations to enhance the scope and quality of implementation of projects. Based on the existing body of knowledge - to which in particular ILO, WORK and IHE have contributed - a course has been established that can be followed via the Internet. This course offers the basic principles of employment-based civil engineering as well as a framework to develop and implement project proposals. Each of the three modules consists of course material (texts, pictures and films) and an individual assignment that the student submits to the lecturer. Next, the University's internship and traineeship programs provide interested candidates an opportunity to render practical assistance at the spot while at the same time collecting and processing data. After their preparation at the UT the students normally spend 3 to 4 months abroad, frequently in outlying areas. The preparation and execution are carried out under supervision of University staff, while the University also provides financial support by paying for the international travel. Besides their direct contribution to development activities, the students' experiences and reports form the input for improvements in implementation and policy making. So far over 20 students have executed such assignments, mainly in South Africa. The oral presentation of the paper includes a demonstration of the Internet-based course and a discussion with participants on concrete project ideas

Design of Cross-chain Internet Order Fulfillment Centres

Many consumers have embraced the option of ordering via the Internet, which has resulted in an enormous increase in direct orders compared to the times when direct ordering was done by catalogue and phone. The fulfillment process in the supply chain is an important factor for these consumers impacting how long they must wait between ordering and delivery. This fact has significantly increased the importance of the back-end fulfillment process. We present a novel supply chain design to enable cross-chain coordination of order fulfillment operations for internet sales. Shared warehousing facilities are used more and more to achieve competitive advantage. This situation asks for new models to enable a smooth warehousing process for each web shop, but at the same time to ensure overall efficiency and effectiveness. This paper introduces a layout model for shared operations under one roof by simultaneously optimizing the overall facility layout and the area layout

Algebraic equations of state for the liquid crystalline phase behavior of hard rods

Based on simplifications of previous numerical calculations [Graf and L\"{o}wen, Phys. Rev. E \textbf{59}, 1932 (1999)], we propose algebraic free energy expressions for the smectic-A liquid crystal phase and the crystal phases of hard spherocylinders. Quantitative agreement with simulations is found for the resulting equations of state. The free energy expressions can be used to straightforwardly compute the full phase behavior for all aspect ratios and to provide a suitable benchmark for exploring how attractive interrod interactions mediate the phase stability through perturbation approaches such as free-volume or van der Waals theory.Comment: 12 pages,accepted for publication in Phys. Rev.