Photographs of coronal streamers from a rocket on 9 May 1967

Analysis of coronal streamers photographed by white light coronagraphs flown on Aerobee 150 vehicl

Spatial analysis of residential development processes:uncovering the Dutch densification potential

Urban areas are rapidly transforming. This is particularly true in the Netherlands where residential development is continuing to claim agricultural land alongside with transforming vacant industrial buildings or filling under-used sites. How to steer future urban development is the topic of heated debates and especially the potential of urban transformations to accommodate the projected growth in housing stock is questioned. We study the feasibility of further intensification with a spatial analysis approach that distinguishes different residential development processes and quantifies their relative importance. Using highly detailed cadastral data related to location, age and function of all individual buildings in the country, we differentiate between processes such as: densification of residential neighbourhoods, transformation of brownfields and greyfields and green field redevelopment. Our results indicate that just over half of the total net increase of around 1 million residences in the past 17 years took place within the existing urban fabric. Only a small proportion of the total increase (5.5%) was placed on former green areas within cities, whereas densification of existing residential areas and transformation accommodated 25% and 21% of the increase respectively. Using binomial logistic regression techniques, we assess the importance of a range of different drivers for this process. The results suggest that there is still substantial scope for further intensification in the coming decades when another million or so new residences have to be constructed

Constructing high-resolution housing price indices for the Netherlands:Spinlab Research Memorandum SL-14

The main research objective of this subproject is to quantify the spatial variation in revenues that can be expected from different types of residential development. Based on this information the relative profitability of different urban development strategies can be assessed in subsequent simulations in a land-use modelling environment. The current report tries to address which factors matter for the added-value of locations in housing prices, looking at factors such as proximity to jobs, distance to train stations, the presence of amenities, or the amount of nature in the area

Are current cities dense enough?:a case study for the Netherlands

One of the main predictions of urban economic theory is that the density of land use reacts to the price of land. For many activities, substitution between land and built-up structure is possible when land is scarce, often by constructing more square meters of floor space on a given amount of land. In recent decades, interest in living and working in (big) cities has increased markedly and urban land prices have increased substantially. Since it appears unlikely that the cost of construction of square meters of floor space has increased much or more than land prices, one expects that optimal land use is now denser than it was in the past. This seems to be confirmed by recent observations of densification in Dutch urban areas. Density of urban areas has implications for traffic, energy use, the total size of the urban area and agglomeration benefits in consumption and production. The sluggish response to higher land prices that is associated with durable real estate and significant adjustment costs probably implies that actual cities are less dense than would be optimal. For this research a spatial model is developed that offers the possibility to systematically investigate the issue of densification. It compares the density of current and alternative uses in the Netherlands. Alternative uses are calculated using for this research constructed hedonic price indices (based on roughly 70% of all house transactions in the Netherlands), construction costs and demolition costs. Analysis of past changes in land use, using information of the relevant prices and construction costs offers the possibility to consider the conditions under which a switch to higher density takes place as well as the ‘jump’ in density that may occur. This offers insight into the speed with which the adjustment to higher density takes place. Moreover, the results provide an important ingredient for a general equilibrium analysis of the way the city would look like if adjustment would be complete. In this analysis it is taken into account that in the rebuilt city more households can live and more workers can be employed in a square kilometre, which implies that with the same population and employment size the city can be smaller. This implies that prices of existing real estate at the current edge of the city will adjust in the absence of population growth, thereby counteracting further densification

Solwind observations of coronal mass ejections during 1979-1985

Coronal observations have been processed for parts of each year during the interval 1979-1985. Around sunspot maximum, coronal mass ejections (CMEs) occurred at the rate of approximately 2 per day, and had a wide range of physical and morphological properties. During the recent years of relatively low sunspot number, CMEs occurred at the rate of only 0.2 per day, and were dominated by the class of so-called streamer blowout. These special CMEs maintained a nearly constant occurrence rate of roughly 0.1 per day during the entire interval

Analysing the potential for further urban densification: a case study for the Netherlands

Urban areas in the Netherlands are rapidly transforming. Many new houses have been built to replace e.g. vacant industrial buildings or fill under-used sites, but it is unclear whether such transformations can accommodate the projected growth in housing stock. This study analyses the spatial and economic feasibility of further intensification. It focusses on quantifying the costs and benefits of two types of densification: changing the main function of current urban areas (e.g. from industrial to residential), or densifying these areas (i.e. adding extra housing units to existing residential areas). In order to quantify the different components of these transformation costs, a literature study and interviews with sector experts were conducted. These main factors influencing the local costs and benefits for densification include: actual land-use, building-type, building age, soil contamination, accessibility, and others. In cooperation with the municipality of The Hague, a case study was set up to analyse a selection of potential transformation sites in the city. This case study aided in revealing the different costs and benefits of transformation projects. Using the insights gained in the literature review and case study analysis and applying a spatially-explicit modelling approach (Land Use Scanner), we simulated potential transformation under different socio-economic scenarios. In this approach the potential for transformation was calculated based on current land-use, zoning regulations, building characteristics, transformation costs and other location-specific characteristics related to for example local accessibility. These suitability scores were used in combination with the regional projected housing demand to find the most likely areas for urban densification/transformation. Furthermore, this tool is used to evaluate the implications of relevant alternative policy measures

Use of the Moon to Distinguish the F from the K Corona Using a Rocket Coronagraph During an Eclipse

F and K corona observations by rocket coronagraph during solar eclips

Associations between coronal mass ejections and interplanetary shocks

Nearly continuous complementary coronal observations and interplanetary plasma measurements for the years 1979-1982 are compared. It is shown that almost all low latitude high speed coronal mass ejections (CME's) were associated with shocks at HELIOS 1. Some suitably directed low speed CME's were clearly associated with shocks while others may have been associated with disturbed plasma (such as NCDE's) without shocks. A few opposite hemisphere CME's associated with great flares seem to be associated with shocks at HELIOS

A nonvolatile analog programmable voltage source using the VIPMOS EEPROM structure

A programmable voltage source using the Vertical Injection Punch-through based MOS EEPROM structure has been developed. The circuit operates at a single 5 V supply and the output voltage is continuously available also during programming. The effect of programming is linearly dependent on the programming time