Leader Firms in the Dutch Maritime Cluster

The cluster-concept is often-used to analyse a country's key industries. The maritime industry is one of the most well-defined clusters in the Netherlands. Although the competitiveness of a cluster depends on the interaction in a cluster, research on cluster dynamics is limited. This paper discusses the presence and impact of 'leader-firms' in the Dutch Maritime Cluster. Leader firms are firms with the ability and incentive to make investments with benefits for other companies in the cluster. Benefits are created in three ways; encouraging innovation, enabling internationalisation and enhancing labour pool quality. The structure of the paper is as follows. First, we briefly discuss the Dutch maritime cluster. Second, we provide a theoretic framework to analyse leader firm behaviour in clusters. Third, we identify the leader firms in the Dutch maritime cluster and analyse their behaviour. In this section the results of surveys among 18 leader firms and the results of 25 case studies of maritime leader firms in the Netherlands are presented. We finalise the paper with conclusions and implications for government policy.

Microfiltratie

Recente ontwikkelingen in de micromechanica maken het mogelijk miniatuurelementen te maken, zoals druk- en flowmeters, inkjet-nozzles, kleppen, vloeistofkanalen, verwarmingselementen, micropompen, mengers, mocrotandwielen en zelfs miniatuurkoelers. De revolutie van de micromechanica is mogelijk gemaakt door het gebruik van dunne film- en fotolithografische technieken die oorspronkelijk waren bedoeld voor fabricage van elektronische componenten. In de micromechanica wordt tevens dankbaar gebruik gemaakt van de uitstekende mechanische eigenschappen van materialen die van oudsher in de halfgeleiderindustrie gebruikt worden, zoals silicium, siliciumnitride, aluminiumoxide, etc. We zullen laten zien dat deze materialen ook gebruikt kunnen worden voor het met grote precisie maken van dunne maar zeer robuuste microzeven

Exploring the temporally resolved electron density evolution in EUV induced plasmas

We measured for the first time the electron density in an Extreme Ultra-Violet induced plasma. This is achieved in a low-pressure argon plasma by using a method called microwave cavity resonance spectroscopy. The measured electron density just after the EUV pulse is $2.6\cdot10^{16}$ m$^{-3}$. This is in good agreement with a theoretical prediction from photo ionization, which yields a density of $4.5\cdot10^{16}$ m$^{-3}$. After the EUV pulse the density slightly increase due to electron impact ionization. The plasma (i.e. electron density) decays in tens of microseconds.Comment: 3 pages, 4 figure

Probing photo-ionization: simulations of positive streamers in varying N2:O2 mixtures

Photo-ionization is the accepted mechanism for the propagation of positive streamers in air though the parameters are not very well known; the efficiency of this mechanism largely depends on the presence of both nitrogen and oxygen. But experiments show that streamer propagation is amazingly robust against changes of the gas composition; even for pure nitrogen with impurity levels below 1 ppm streamers propagate essentially with the same velocity as in air, but their minimal diameter is smaller, and they branch more frequently. Additionally, they move more in a zigzag fashion and sometimes exhibit a feathery structure. In our simulations, we test the relative importance of photo-ionization and of the background ionization from pulsed repetitive discharges, in air as well as in nitrogen with 1 ppm O2 . We also test reasonable parameter changes of the photo-ionization model. We find that photo- ionization dominates streamer propagation in air for repetition frequencies of at least 1 kHz, while in nitrogen with 1 ppm O2 the effect of the repetition frequency has to be included above 1 Hz. Finally, we explain the feather-like structures around streamer channels that are observed in experiments in nitrogen with high purity, but not in air.Comment: 12 figure

A novel method for the fabrication of freestanding PZT features on substrates

A simple and cheap micromoulding fabrication route was developed to prepare freestanding piezo active features. Dimensions as small as 200 μm by 200 μm and 40 μm high were successfully fabricated via a replication technique. The lead zirconate titanate features were thoroughly characterized using SEM, EDX and XRD analysis. The properties of the features were influenced by several factors like the type of substrate, sintering temperature and sintering atmosphere. Features prepared on alumina substrates and sintered in lead atmosphere displayed a structure with reproducible dimensions. Next to that they were low in porosity and had a comparable composition with respect to the starting powder. The remanent polarization of the lead zirconate film was 12.3 μC/cm2 and the coercive field was 8.7 kV/cm

Amoxicillin concentrations in relation to beta-lactamase activity in sputum during exacerbations of chronic obstructive pulmonary disease

Background: Acute exacerbations of chronic obstructive pulmonary disease (COPD) are often treated with antibiotics. Theoretically, to be maximally effective, the antibiotic concentration at sites of infection should exceed the minimum inhibitory concentration at which 90% of the growth of potential pathogens is inhibited (MIC90). A previous study showed that most hospitalized COPD patients had sputum amoxicillin concentrations <MIC90 when treated with amoxicillin/clavulanic acid. Those with adequate sputum concentrations had better clinical outcomes. Low amoxicillin concentrations can be caused by beta-lactamase activity in the lungs. This study investigated whether patients with sputum amoxicillin concentrations <MIC90 had higher beta-lactamase activity in sputum than patients with a concentration ≥MIC90. Methods: In total, 23 patients hospitalized for acute exacerbations of COPD and treated with amoxicillin/clavulanic acid were included. Sputum and serum samples were collected at day 3 of treatment to determine beta-lactamase activity in sputum and amoxicillin concentrations in both sputum and serum. Results: We found no difference in beta-lactamase activity between patients with sputum amoxicillin concentrations <MIC90 and ≥MIC90 (P=0.79). Multivariate logistic regression analysis showed no significant relationship between beta-lactamase activity and sputum amoxicillin concentrations <MIC90 or ≥MIC90 (odds ratio 0.53; 95% confidence interval 0.23–1.2; P=0.13). Amoxicillin concentrations were <MIC90 in 78% of sputum samples and in 30% of serum samples. Conclusion: In patients treated with amoxicillin/clavulanic acid for an acute exacerbation of COPD, sputum beta-lactamase activity did not differ between those with sputum amoxicillin concentrations <MIC90 or ≥MIC90. The finding that the majority of patients had sputum amoxicillin concentrations <MIC90 suggests that current treatment with antibiotics for acute exacerbations of COPD should be optimized