Influence of texture on the switching behavior of Pb(Zr0.70Ti0.30)O3 sol-gel derived thin films

Rhombohedral Pb(Zr0.70Ti0.30)O3 thin films of four different well-defined textures, namely, (100), (111), bimodal (110)/(111), and (100)/(111), were prepared by a sol-gel method. The films were characterized in terms of grain size, presence of second phases, surface roughness, columnarity of grains, and other microstructural features. The dielectric, ferroelectric, and fatigue properties were investigated, with emphasis on the hysteresis switching characteristics. Results are discussed from the reference point of the allowable spontaneous polarization directions available for the different textures. The values of coercive field, remanent and saturation polarization, and slope of the loop at the coercive field, at saturating fields can be qualitatively explained based on the texture, independent of microstructural differences. The occurrence of surface pyrochlore, however, is observed to affect the functionality of the saturation curves, particularly for the samples of bimodal texture. Shearing of the hysteresis curves of the bimodal films is also attributed to surface microstructural features. The occurrence of nonswitching 71° or 109° domains in the (111) and (110)/(111) textured films is hypothesized based on a comparison with the data from the (100) textured film. Corrected saturation polarization values agree with the spontaneous polarization values of rhombohedral PZT single crystals and published calculated values for rhombohedral PZT ceramics. The fatigue characteristics show increases in the switching component of polarization in the range 103−107 bipolar cycles, particularly for the (111) textured sample. Onset of fatigue is observed for all samples between 107 and 108 switching cycle

Retrospective analysis of the impact of respiratory motion in treatment margins for frameless lung SBRT based on respiratory-correlated CBCT data-sets.

To investigate the impact of respiratory motion in the treatment margins for lung SBRT frameless treatments and to validate our treatment margins using 4D CBCT data analysis. Two hundred and twenty nine fractions with early stage NSCLC were retrospectively analyzed. All patients were treated in frameless and free breathing conditions. The treatment margins were calculated according to van Herk equation in Mid-Ventilation. For each fraction, three 4D CBCT scans, pre- and postcorrection, and posttreatment, were acquired to assess target baseline shift, target localization accuracy and intra-fraction motion errors. A bootstrap analysis was performed to assess the minimum number of patients required to define treatment margins. The retrospectively calculated target-baseline shift, target localization accuracy and intra-fraction motion errors agreed with the literature. The best tailored margins to our cohort of patients were retrospectively computed and resulted in agreement with already published data. The bootstrap analysis showed that fifteen patients were enough to assess treatment margins. The treatment margins applied to our patient's cohort resulted in good agreement with the retrospectively calculated margins based on 4D CBCT data. Moreover, the bootstrap analysis revealed to be a promising method to verify the reliability of the applied treatment margins for safe lung SBRT delivery

Fear of crime on the rail networks: Perceptions of the UK public and British Transport Police

Counter-terrorism on the rail network is vital to the security of the United Kingdom. The British Transport Police (BTP) employ covert and overt security measures to prevent crime, which includes: closed circuit television, armed police, unarmed polisce, police community support officers, police dogs, stops and searches and awareness campaigns. All security measures aim to deter crime while importantly reassuring the public. We surveyed both members of the public and BTP officers about the perceived effectiveness of current security measures, specifically with regards to fear of terrorism. Feelings of reassurance and the perceived effectiveness of security measures were positively related. The most effective and reassuring security measure was the use of armed police; whereas the least effective and reassuring was the use of awareness campaigns. However, interestingly, qualitative analyses suggested that an increase in armed police without informed awareness campaigns would have a negative impact on public reassurance by increasing fear

The Nature of Gender: work, gender and environment

Gender has long been recognised as important within environmental issues, but exactly how and in what contexts it is relevant has been hotly debated. As feminist theorising around women and gender has changed, so have conceptualisations about gender and environment, leading to a key debate within ecofeminism and related literatures about whether there is an essential or a contingent relationship between women and natural environments. Within geography, most political ecologists work with the assumption that the gender-environment nexus is a contingent relationship, and thus investigate how gender relations are salient in the symbolic and material construction of environmental issues. This paper seeks to build from this work and again raise the question of how gender is conceptualised in relation to environment. I begin by briefly reviewing some of the work that has been done on gender and environment and then draw from post-structural feminism to suggest that gender itself has been under-theorised in work on environment. Once gender is re-conceptualized as a process, the dynamic relationship between gender, environment and other aspects of social and cultural life can be brought into view. What emerges is the need for political ecologists to examine gender beyond the household and community and the need to re-conceptualise the gender-environment nexus. A case study of community forestry in Nepal is used to illustrate the importance of interrogating the processes by which gender relations become salient and are reproduced symbolically and materiall

Abundance and scarcity: classical theories of money, bank balance sheets and business models, and the British restriction of 1797‐1818.

The thesis looks through the lens of bank balance sheet accounting to investigate the structural change in the British banking system between 1780 and 1832, and how classical quantity theorists of money attempted to respond to the ensuing financialisation of the wartime economy with its growing reliance on credit funded with paper-based instruments (the ‘Vansittart system’ of war finance). The thesis combines contributions to three separate fields to construct a holistic historical example of the challenges faced by monetary economists when ‘modelling’ financial innovation, credit growth, ‘fringe’ banking, and agent incentives – at a time of radical experimentation: the suspension of the 80-year-old gold standard (“the Restriction”). First, critical text analysis of the history of economics argues that the 1809-10 debate between Ricardo and Bosanquet at the peak of the credit boom, bifurcated classical theory into two timeless competing policy paradigms advocating the ‘Scarcity’ or ‘Abundance’ of money relative to exchange transactions. The competing hypotheses regarding the role of money and credit are identified and the rest of the thesis examines the archival evidence for each. Second, the core of the thesis contributes to the historical literature on banking in relation to money by reconstructing a taxonomy of bank business models, their relationships with the London inter-bank settlement system, and their responses to the Restriction - drawing on some 17,000 mostly new data points collected from the financial records of London and Country banks. The final section contributes to the economic history of money by constructing aggregated views of total bank liabilities from the firm-level data, scaled to recently available British GDP estimates. These are examined to establish (with hindsight) the relative merits and lacuna of the competing theoretical hypotheses postulated by political economists. It was the period of deleveraging after 1810 that revealed the lacuna of both paradigms

The making of driving cultures

Overview Culture matters. It is the mechanism through which we come to understand ourselves and our relationship to the world. In the U.S., cars and driving are intimately connected to our individual and collective sense of self-who we are, what we believe, value, and aspire to achieve, and how we interact with others. From the promise of Herbert Hoover's 1928 presidential campaign slogan, "a chicken in every pot and a car in every garage," to conflicting portrayals of the sport utility vehicle as a means to experience nature or as a "gas guzzling" status symbol, the car and driving have always referenced the American experience of and desire for freedom, individualism, self-realization, prosperity, and progress. Culture is also inherently material, accounting for how groups identify themselves and interact with their environment through developing, building, and using artifacts. A car's design is as much a response to drivers' fantasies of power, control, and speed as it is to the utilitarian components of travel. The choice to drive is affected by people's beliefs and values regarding appropriate uses of vehicles and the resources required to operate them. And driving itself changes how people understand time and space, altering their perception and experience of distance. Cars as material objects and driving as an embodied experience, therefore, reflect and reinforce our cultural identity. The preeminence of cars and driving in American culture makes the relative silence on the high number of deaths and injuries due to car crashes a perplexing phenomenon. Although total U.S. fatalities from recent high-profile catastrophes-the Oklahoma City bombing, shootings at Columbine High School, terrorist attacks on September 11, 2001, and Hurricane Katrinacombined have numbered less than 5,000, these deaths and the events that caused them have had considerable influence on the American political, economic, and cultural landscapes. In contrast, the 42,636 lives lost in 2004 alone as a result of vehicle crashes on U.S. roadways barely registered in the collective consciousness of the American public. How can we lose an average of 116 lives each day in crashes that are largely preventable and not have more public outcry, media coverage, and government intervention