van J Jan Dijk

Residential Choice Behaviour of Dual Earner Households: A Decompositional Joint Choice Model

The residential location decision process has been studied for several decades with use of different approaches. One such approach that has received considerable attention in urban planning is the decompositional approach. This approach involves measuring individual preferences. Residential choice behaviour is, however, often the result of a joint decisionmaking process, especially in the case of dual earner households. In the present paper, the original modelling approach is therefore extended to a model of joint decisionmaking. The results of an empirical application in the context of residential choice behaviour in the Netherlands are described.

A model study of propagation of the first ionization wave during breakdown in a straight tube containing argon

The mechanisms responsible for the propagation of the first anode directed ionization wave that occurs in a straight discharge tube during breakdown are studied by means of a fluid model. The discharge tube contains argon at a pressure of a few Torr and is operated at a dc voltage with the cathode heated to thermal electron emission temperatures. The two-dimensional model incorporates continuity and momentum equations for the electrons, for several effective excited states and for the ions, a balance equation for the electron energy and the Poisson equation. The model is capable of describing the first ionization front in a way that is qualitatively consistent with observations made in experiments. The mechanisms behind the breakdown evolution are investigated by considering the temporal and spatial evolution of the quantities described by the model. Previously, researchers have described this breakdown evolution in terms of an RC-line circuit. The validity of this picture is surveyed by considering the distribution of charges within the lamp. The effect of control parameters on the breakdown process and the assumptions that affect the validity of the model for later stages in breakdown are considered.

A bactracking algorithm for exact counting of internal molecular energy levels

An algorithm is described for counting exactly internal molecular energy levels. Difficulties in the concept of the density of states are reinvestigated. The influence of anharmonicity is shortly discussed and it is shown that reliable densities can only be obtained for low energies if anharmonicity constants are used.

Plasma modelling and numerical simulation

Plasma modelling is an exciting subject in which virtually all physical disciplines are represented. Plasma models combine the electromagnetic, statistical and fluid dynamical theories that have their roots in the 19th century with the modern insights concerning the structure of matter that were developed throughout the 20th century. The present cluster issue consists of 20 invited contributions, which are representative of the state of the art in plasma modelling and numerical simulation. These contributions provide an in-depth discussion of the major theories and modelling and simulation strategies, and their applications to contemporary plasma-based technologies. In this editorial review, we introduce and complement those papers by providing a bird’s eye perspective on plasma modelling and discussing the historical context in which it has surfaced.

Numerical description of discharge characteristics of the plasma needle

The plasma needle is a small atmospheric, nonthermal, radio-frequency discharge, generated at the tip of a needle, which can be used for localized disinfection of biological tissues. Although several experiments have characterized various qualities of the plasma needle, discharge characteristics and electrical properties are still not well known. In order to provide initial estimates on electrical properties and quantities such as particle densities, we employed a two-dimensional, time-dependent fluid model to describe the plasma needle. In this model the balance equation is solved in the drift-diffusion approach for various species and the electron energy, as well as Poisson’s equation. We found that the plasma production occurs in the sheath region and results in a steady flux of reactive species outwards. Even at small (<0.1%) admixtures of N2 to the He background, N2+ is the dominant ion. The electron density is typically 1011cm−3 and the dissipated power is in the order of 10mW. These results are con...

Ab initio CI calculation of the vibrational structure of the 1(nπ∗) transition in formaldehyde

This paper reports an ab initio CI calculation of the radiative 1A1→1A2 transition of H2CO and D2CO. Throughout the calculation the electronic wavefunctions and transition moments are explicitly calculated as functions of the nuclear geometry, contrary to the conventional Herzberg–Teller approach. The evaluation of the vibrational wavefunctions and integrals was made numerically. The results show that the excited state frequency for mode 3 has to be reassigned and that the calculated vibrational structure agrees well with the experimental intensities.

Pulse shape influence on the atmospheric barrier discharge

In this letter we compare the effect of a radio-frequency sine, a low frequency sine, a rectangular and a pulsed dc voltage profile on the calculated electron production and power consumption in the dielectric barrier discharge. We also demonstrate using calculated potential distribution profiles of high time and space resolution how the pulsed dc discharge generates a secondary discharge pulse by deactivating the power supply.

A self-consistent LTE model of a microwave-driven, high-pressure sulfur lamp

A one-dimensional LTE model of a microwave-driven sulfur lamp is presented to aid our understanding of the discharge. The energy balance of the lamp is determined by Ohmic input on one hand and transport due to conductive heat transfer and molecular radiation on the other. We discuss the origin of operational trends in the spectrum, present the model and discuss how the material properties of the plasma are determined. Not only are temperature profiles and electric field strengths simulated but also the spectrum of the lamp from 300 to 900 nm under various conditions of input power and lamp filling pressure. We show that simulated spectra demonstrate observed trends and that radiated power increases linearly with input power as is also found from experiment.

Ab initio CI calculation of the radiationless transition of the 1(nπ) state of formaldehyde

This paper reports an ab initio CI calculation of the radiationless decay of the formaldehyde 1A2 state. First we derive quantitative conditions, which a basis set must satisfy if it is to be used for describing radiationless decay. We checked these conditions for the formaldehyde molecule and found them to be satisfied for the adiabatic Born–Oppenheimer set used in the calculation. We then derive a general equation for the coupling elements resulting from this basis set. With the method used, rotational coupling could be treated completely equivalent with vibrational coupling; this rotational coupling turned out to be not important in formaldehyde however. The coupling elements for D2CO are a factor 10 smaller than the corresponding ones in H2CO. The results of the calculation show, that the internal conversion in formaldehyde is an example of the so‐called resonance case. Therefore the decay cannot be described by the model proposed by Yeung and Moore, where S1→S0 internal conversion is the rate determi...

On the regime transitions during the formation of an atmospheric pressure dielectric barrier glow discharge

The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature. If during the electrical current pulse a glow discharge is reached, then this pulse will last only a few microseconds in operating periods of sinusoidal voltage with lengths of about 10 to 100 µs. In this paper we demonstrate that right before a glow discharge is reached, the discharge very closely resembles the commonly assumed Townsend discharge structure, but actually contains some significant differing features and hence should not be considered as a Townsend discharge. In order to clarify this, we present calculation results of high time and space resolution of the pulse formation. The results indicate that indeed a maximum of ionization is formed at the anode, but that the level of ionization remains high and that the electric field at that time is significantly disturbed. Our results also show where this intermediate structure comes from. (Some figures in this article are in colour only in the electronic version)