119 resultados para Mixing property
Resumo:
The nonlinear scattering of two Gaussian pulses with different central frequencies incident at slant angles on the periodic stack of binary semiconductor layers has been modelled in the self-consistent problem formulation taking into account the dynamics of charges. The effects of the pump pulse length and central frequencies, and the stack physical and geometrical parameters on the properties of the emitted combinatorial frequency waveforms are analysed and discussed.
Resumo:
The properties of combinatorial frequency generation by two-tone Gaussian pulses incident at oblique angles on quasiperiodic (Fibonacci and Thue-Morse) stacks of binary semiconductor layers are discussed. The analysis has been performed using the self-consistent model taking into account the nonlinear dynamics of mobile charges in the layers. The effects of the stack arrangements and constituent layer parameters on the combinatorial frequency waveforms are presented for the specific structures of both types
Resumo:
This paper will discuss the issues of spatial segregation in the divided city context,focusing on Belfast as a case study it will discuss, issues that limit the inclusivity of shared space in the city, the challenge of insular spatial patterns created by division, and the micro politics of everyday contact. It will argue the significance of creating everyday space to enable practical socio-spatial interaction between divided groups and propose that areas on community borders can be developed as active spaces accommodating services that the communities need, use, and want on an everyday basis, by doing so it offers a potential form valuable contact. It will report on an ongoing study which examines such sites located on community border and assesses their capacity to act as beneficial ‘spaces of engagement’ for communities set within divided context.
Resumo:
The chemisorption of CO on metal surfaces is widely accepted as a model for understanding chemical bonding between molecules and solid surfaces, but is nevertheless still a controversial subject. Ab initio total energy calculations using density functional theory with gradient corrections for CO chemisorption on an extended Pd{110} slab yield good agreement with experimental adsorption energies. Examination of the spatial distribution of individual Bloch states demonstrates that the conventional model for CO chemisorption involving charge donation from CO 5 sigma states to metal states and back-donation from metal states into CO 2 pi states is too simplistic, but the computational results provide direct insight into the chemical bonding within the framework of orbital mixing (or hybridisation). The results provide a sound basis for understanding the bonding between molecules and metal surfaces.
Resumo:
Property as a human rights concern is manifested through its incorporation in international instruments and as a subject of the law through property-related cases considered by international human rights organs. Yet, for the most part, the relationship between property and human rights has been discussed in rather superficial terms, lacking a clear substantive connection or common language. That said, the currents of globalisation have witnessed a new era of interrelation between these two areas of the law, including the emergence of international intellectual property law and the recognition of indigenous claims, which, in fundamental ways, speak to an engagement with human rights law.
This collection starts the conversation between human rights lawyers and property lawyers and explores analytical approaches to the increasing relationship between property and human rights in a global context. The chapters engage with key theoretical and policy debates and range across three main themes: the re-evaluation of the public/private divide in the law; the tensions between the market and social justice in development and the balance between the rights of individuals and those of communities. The chapters adopt a global, comparative perspective and engage in case studies from countries including India, Philippines, Brazil, the United States, the United Kingdom and includes various regions of Africa and Europe.
Resumo:
A significant portion of the UK’s transportation system relies on a network of geotechnical earthworks (cuttings and embankments) that were constructed more than 100 years ago, whose stability is affected by the change in precipitation patterns experienced over the past few decades. The vulnerability of these structures requires a reliable, cost- and time-effective monitoring of their geomechanical condition. We have assessed the potential application of P-wave refraction for tracking the seasonal variations of seismic properties within an aged clay-filled railway embankment, located in southwest England. Seismic data were acquired repeatedly along the crest of the earthwork at regular time intervals, for a total period of 16 months. P-wave first-break times were picked from all available recorded traces, to obtain a set of hodocrones referenced to the same spatial locations, for various dates along the surveyed period of time. Traveltimes extracted from each acquisition were then compared to track the pattern of their temporal variability. The relevance of such variations over time was compared with the data experimental uncertainty. The multiple set of hodocrones was subsequently inverted using a tomographic approach, to retrieve a time-lapse model of VPVP for the embankment structure. To directly compare the reconstructed VPVP sections, identical initial models and spatial regularization were used for the inversion of all available data sets. A consistent temporal trend for P-wave traveltimes, and consequently for the reconstructed VPVP models, was identified. This pattern could be related to the seasonal distribution of precipitation and soil-water content measured on site.
Resumo:
Noncollinear four-wave-mixing (FWM) techniques at near-infrared (NIR), visible, and ultraviolet frequencies have been widely used to map vibrational and electronic couplings, typically in complex molecules. However, correlations between spatially localized inner-valence transitions among different sites of a molecule in the extreme ultraviolet (XUV) spectral range have not been observed yet. As an experimental step toward this goal, we perform time-resolved FWM spectroscopy with femtosecond NIR and attosecond XUV pulses. The first two pulses (XUV-NIR) coincide in time and act as coherent excitation fields, while the third pulse (NIR) acts as a probe. As a first application, we show how coupling dynamics between odd- and even-parity, inner-valence excited states of neon can be revealed using a two-dimensional spectral representation. Experimentally obtained results are found to be in good agreement with ab initio time-dependent R-matrix calculations providing the full description of multielectron interactions, as well as few-level model simulations. Future applications of this method also include site-specific probing of electronic processes in molecules.
Resumo:
Relatively little has been written on the connection between property and emotions from a legal perspective, despite the centrality of property in everyday life and the complex relationships that exist between owners and their property. Scholars working in other disciplines have analyzed these links, identifying ‘proprietary’ emotions and corresponding emotional traits. However, little has been mapped onto the field of law. This paper looks at key emotions surrounding property as identified in psychological and, to a lesser extent, sociological literature. After mapping these onto selected areas of property law, it posits the need for a deeper and more collective field of inquiry.
Resumo:
Background
Childhood deprivation is a major risk to public health. Poor health in the early years accumulates and is expressed in adult health inequalities. The importance of social mobility - moves into and out of poverty or, indeed, change in relative affluence - for child wellbeing is less well understood. Home ownership and house value may serve as a useful measure of relative affluence and deprivation.
Method
Analysis of the Northern Ireland Longitudinal Study dataset focused on cohort members aged 18 and under at the 2001 census and their families. Using housing tenure and house value reported in 2001 and 2011, moves along the “housing ladder” over ten years were identified. Outcome measures were physical disability and mental health status as reported in 2011. Logistic regression models tested if health outcomes varied by upward and downward changes in house value.
Results
After controlling for variations in age, sex, general health and social class, mental health is worse among those who moved to a lower value house. Compared to ‘no change’, those moving from the upper quintile of house value into social renting accommodation were almost six times more likely to report poor mental health (OR 5.90 95% CI 4.52, 7.70). Conversely, those experiencing the greatest upward movement were half as likely to report poor mental health (OR 0.46 95% CI 0.31, 0.68). There were smaller associations between physical health and downward (OR 2.66 95% CI 2.16, 3.27), and upward (OR 0.75 95% CI 0.61, 0.92) moves.
Conclusion
Poor mental health is more strongly associated with declines in living standards than with improvements. The gradient appears at multiple points along this proxy affluence-deprivation spectrum, not only at the extremes. Further research should explore whether circumstances surrounding moves, or change in social position explains the differential association between the health correlates of upward versus downward mobility.
Resumo:
A complete review of the published data on the mixing enthalpies of mixtures containing ionic liquids, measured directly using calorimetric techniques, is presented in this paper. The field of ionic liquids is very active and a number of research groups in the world are dealing with different applications of these fluids in the fields of chemistry, chemical engineering, energy, gas storage and separation or materials science. In all these fields, the knowledge of the energetics of mixing is capital both to understand the interactions between these fluids and the different substrates and also to establish the energy and environmental cost of possible applications. Due to the relative novelty of the field, the published data is sometimes controversial and recent reviews are fragmentary and do not represent a set of reliable data. This fact can be attributed to different reasons: (i) difficulties in controlling the purity and stability of the ionic liquid samples; (ii) availability of accurate experimental techniques, appropriate for the measurement of viscous, charged, complex fluids; and (iii) choice of an appropriate clear thermodynamic formalism to be used by an interdisciplinary scientific community. In this paper, we address all these points and propose a critical review of the published data, advise on the most appropriate apparatus and experimental procedure to measure this type of physical-chemical data in ionic liquids as well as the way to treat the information obtained by an appropriate thermodynamic formalism.