A new method for measuring the transfer of oxygen in liquids. MeasurementS of oxygen transfer from bubbles in water and in water + 1-butanol

At the base of a column of liquid 20 cm in diameter and well over 1 m in height, oxygen bubbles of constant volume were formed and released with a frequency of approximately one bubble per second. Measurements were carried out on bubbles with volumes ranging from 0·2 to 2 cm³. The mass transfer per bubble was determined by measuring the increase in oxygen concentration of the liquid phase with an oxygen electrode and counting the number of bubbles. The results were reproducible within 3 per cent, and it is probable that still better results are attainable with this method.The measurements were initially performed in distilled water to test the apparatus. Later, water—butanol mixtures were employed in order to determine the influence of butanol on the mass transfer. The results of the latter experiments have been checked with a theory published previously [23, 24]. Theory and results appear to be in satisfactory agreement.     

Ethnic differences in realising desires to leave urban neighbourhoods

Selective mobility into and out of urban neighbourhoods is one of the main driving forces of segregation. Earlier research has found group differences in who wants to leave or who leaves certain types of neighbourhoods. A factor that has received little attention so far is that some residents will have a desire to leave their neighbourhood, but are unable to do so. If there are differences between population groups in the realisation of desires to leave the neighbourhood, this might lead to involuntary segregation. This paper uses a unique combination of register data and survey data. We combine data from a large housing survey in the Netherlands (WoON) with longitudinal register data from the Netherlands (SSD) which contains individual-level information on residential mobility histories. This allows us to study whether households with a desire to leave their neighbourhood do realise this desire and which households are successful in leaving which neighbourhoods. A more thorough insight in who wants to leave which neighbourhoods but is unable to do so will contribute to a better understanding of selective mobility and segregation. We find that ethnic minorities and low-income households are less likely to realise a desire to leave their neighbourhood. We expected that ethnic minorities would be especially unsuccessful in realising desires to leave minority concentration neighbourhoods; however, for none of the ethnic groups we found an effect of neighbourhood ethnic composition on the realisation of desires to leave.     

Neighbourhood Restructuring and Residential Relocation: Towards a Balanced Perspective on Relocation Processes and Outcomes

This introductory paper to this special issue of Housing Studies questions whether various characteristics of the debate and research on gentrification, displacement and restructuring justify a largely negative perspective on the processes and outcomes of ‘forced’ residential relocation. We argue that a proper and fuller consideration of issues around policy, context, process and outcomes enable researchers and commentators to avoid ready characterisations and self-fulfilling investigations of restructuring which serve to present it as a singular (and somewhat suspicious or conspiratorial) phenomenon. For this purpose, we present a broad conceptual framework for restructuring and relocation studies, based on these four themes. Subsequently, we review major issues in restructuring and gentrification discourses, and briefly reflect upon some of the factors underlying the negative loading of the term displacement. We also identify caveats in the evidence base of relocation studies, both in the United States and in Europe. Finally, we introduce the papers in this special issue. The overall aim of this issue is to offer a more open, balanced starting position for analysis of urban restructuring processes and relocation outcomes, particularly in relation to areas of social housing.     

Multi-level Modeling of Silica–Template Interactions During Initial Stages of Zeolite Synthesis

Zeolite synthesis is driven by structure-directing agents, such as tetrapropyl ammonium ions (TPA⁺) for Silicalite-1 and ZSM-5. However, the guiding role of these organic templates in the complex assembly to highly ordered frameworks remains unclear, limiting the prospects for advanced material synthesis. In this work, both static ab initio and dynamic classical modeling techniques are employed to provide insight into the interactions between TPA⁺ and Silicalite-1 precursors. We find that as soon as the typical straight 10-ring channel of Silicalite-1 or ZSM-5 is formed from smaller oligomers, the TPA⁺ template is partially squeezed out of the resulting cavity. Partial retention of the template in the cavity is, however, indispensable to prevent collapse of the channel and subsequent hydrolysis.

Is bioethanol a sustainable energy source? An energy-, exergy-, and emergy-based thermodynamic system analysis

Biofuels are widely seen as substitutes for fossil fuels to offset the imminent decline of oil production and to mitigate the emergent increase in GHG emissions. This view is, however, based on too simple an analysis, focusing on only one piece in the whole mosaic of the complex biofuel techno-system, and such partial approaches may easily lead to ideological bias based on political preference. This study defines the whole biofuel techno-system at three scales, i.e., the foreground production (A), the background industrial network (B, including A), and the supporting Earth biosphere (C, including B). The thermodynamic concepts of energy, exergy and emergy measure various flows at these three scales, viz. primary resources, energy and materials products, and labor and services. Our approach resolves the confusion about scale and metric: direct energy demand and direct exergy demand apply at scale A; cumulative energy demand and cumulative exergy demand apply at scale B; and energy is applied at scale C, where it is named emergy, while exergy also can be applied at scale C. This last option was not examined in the present study.The environmental performance of the system was assessed using a number of sustainability indicators, including resource consumption, input renewability, physical benefit, and system efficiency, using ethanol from corn stover in the US as a technology case. Results were compared with available literature values for typical biofuel alternatives. We also investigated the influence of methodological choices on the outcomes, based on contribution analysis, as well as the sensitivity of the outcomes to emergy intensity. The results indicate that the techno-system is not only supported by commercial energy and materials products, but also substantially by solar radiation and the labor and services invested. The bioethanol techno-system contributes to the overall supply of energy/exergy resources, although in a less efficient way than the process by which the Earth system produces fossil fuels.Our results show that bioethanol cannot be simply regarded as a renewable energy resource. Furthermore, the method chosen for the thermodynamic analysis results in different outcomes in terms of ranking the contributions by various flows. Consequently, energy analysis, exergy analysis, and emergy analysis jointly provide comprehensive indications of the energy-related sustainability of the biofuel techno-system. This thermodynamic analysis can provide theoretical support for decision making on sustainability issues.     

Psychopathology in young adults with congenital heart disease. Follow-up results

Non-steroidal anti-inflammatory drugs inhibit constitutive (COX-1) and induced cyclooxygenase (COX-2), blocking prostaglandin production. We have compared the effects on nociceptive reflexes of meloxicam, which is COX-2 selective, with indomethacin, which is non-selective, using an in vitro spinal cord preparation. Cords were taken from naive rats, and from rats with carrageenan-induced hyperalgesia of one hindpaw. Reflex thresholds were lower in carrageenan preparations. Superfusion with meloxicam (10-100 microM) dose-dependently inhibited baseline reflexes and wind-up in normal and carrageenan preparations, whereas indomethacin (100-300 microM) had no effect. Thus meloxicam inhibits spinal reflexes, whereas indomethacin does not, despite its high affinity for both COX isoforms. We conclude that meloxicam has spinal antinociceptive actions which cannot be explained by the current concept of COX inhibition.     

Isolation of two isomeric 2, 6-nonadienals and two isomeric 4-heptenals from beef and mutton tallow

By the use of mainly chromatographic and UV spectrophotometric techniques, 4cis- and 4trans-heptenal (with a “green” odor, characterized in high dilution as tallowy, creamy, butterscotch-like) and 2trans,6cis- and 2trans,6trans-nonadienal (with a “green”-cucumber-like and a tallowy odor) were isolated from reverted beef and mutton tallow. Presented in part by G. Hoffmann at the 7th ISF-Congress, Hamburg, October 1964.     

An industrial view on compact modeling

Compact modeling is an area that gets more and more mature. Collaborations and standardization efforts have emerged. In this paper we present some special requirements that are important when constructing physics-based compact models. We will substantiate our statements on two recent examples, an inductor model and a MOSFET model.     

Effects of Daniella oliveri Wood Flour Characteristics on the Processing and Functional Properties of Wood Polymer Composites

The effects of particle sizes/distribution and contents on the processing, changes in microstructure and functional properties of wood polymer composites (WPCs) prepared from virgin high-density polyethylene (vHDPE) and sodium hydroxide (NaOH) treated Daniella oliveri wood flour via compression molding have been explored. Findings from this study suggested that an appropriate choice of wood flour characteristics could improve the interactions between the wood flour and the vHDPE matrix by eliminating incomplete wetting, segregation, and agglomeration of wood flour particles during processing while enhancing mechanical and thermal properties of the composites. Properties of the WPCs were optimized when wood flour of particle sizes/distribution and contents of +210–300 µm and 35 wt%, respectively, were blended with vHDPE matrix.     

Dealing with living in poor neighbourhoods

In this prologue to the special issue, the guest editors place the contributions in the context of current debates on living in concentrated poverty neighbourhoods. These debates concern two broad categories of residents: poor households that are assisted to move from concentrations of poverty to lower-poverty areas (movers); and households (not exclusively the poor) that cannot move out of poor neighbourhoods or are not willing to do so, for various reasons (stayers). For the first category, the main issue is whether housing vouchers provide movers only with better housing or also with other social, psychological and economic benefits. A wealth of (partly contradictory) evidence justifies exploring a fundamental question: What should housing vouchers do? With regard to those unwilling or unable to move out of poor neighbourhoods, we focus on how residents cope with the recurrent problems and stressful circumstances in poor neighbourhoods. Here, four interrelated concepts are central to our discussion: place attachment, coping tactics, territoriality, and social network formation. Our discussion paves the way for the subsequent five papers, each dealing with one of the selected topics. The aim of this special issue is to provide new evidence that underpins or questions the current debates on living in or leaving neighbourhoods with concentrated poverty. The research reported here was done in the United States, Great Britain and the Netherlands.