61 resultados para Weak confinement regime


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The rheological properties of supramolecular soft functional materials are determined by the networks within the materials. This research reveals for the first time that the volume confinement during the formation of supramolecular soft functional materials will exert a significant impact on the rheological properties of the materials. A class of small molecular organogels formed by the gelation of N-lauroyl-L-glutamic acid din-butylamide (GP-1) in ethylene glycol (EG) and propylene glycol (PG) solutions were adopted as model systems for this study. It follows that within a confined space, the elasticity of the gel can be enhanced more than 15 times compared with those under un-restricted conditions. According to our optical microscopy observations and rheological measurements, this drastic enhancement is caused by the structural transition from a multi-domain network system to a single network system once the average size of the fiber network of a given material reaches the lowest dimension of the system. The understanding acquired from this work will provide a novel strategy to manipulate the network structure of soft materials, and exert a direct impact on the micro-engineering of such supramolecular materials in micro and nano scales.

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This article is concerned with the reproduction of gender inequality in social work and the extent to which the presence of men in the profession challenges discriminatory processes and occupational segregation. Although it is argued that men need to take more responsibility for caring roles in professions like social work, many of the rationales for encouraging more men to enter social work are unlikely to support alternative masculinities that will challenge gender inequalities. Only a profeminist commitment informing antisexist practices will enable men to address gender inequality in social work.

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Formation of autonomous mobile robots to an arbitrary geometric pattern in a distributed fashion is a fundamental problem in formation control. This paper presents a new fully distributed, memoryless (oblivious) algorithm to the formation control problem via distributed optimization techniques. The optimization minimizes an appropriately defined difference function between the current robot distribution and target geometric pattern. The optimization processes are performed independently by individual robots in their local coordinate system. A movement strategy derived from the results of the distributed optimizations guarantees that every movement makes the current robot configuration approaches the target geometric pattern until the final pattern is reached.

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The rheological properties of a hierarchically structured supramolecular soft material are mainly determined by the structure of its network. Controlling the thermodynamic driving force of physical gels (one type of such materials) during the formation has proven effective in manipulating the network structure due to the nature of nucleation and growth of the fiber network formation in such a supramolecular soft material. Nevertheless, it is shown in this study that such a property can be dramatically influenced when the volume of the system is reduced to below a threshold value. Unlike un-confined systems, the network structure of such a soft material formed under volume confinement contains a constant network size, independent of the experimental conditions, i.e. temperature and solute concentration. This implies that the size of the fiber networks in such a material is invariable and free from the influence of external factors, once the volume is reduced to a threshold. The observations of this work are significant in the control of the formation of fibrous networks in materials of this type.

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This thesis establishes that exchange rate regime choice is persistent for low-income and high-income countries. It also confirms the crucial role of capital account openness, financial development and product diversification as possible determinants of regime choice. Moreover, the thesis provides strong evidence that exchange rate regime influences fiscal discipline directly and through interaction with trade openness.

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We apply a Markov switching model to investigate the possibility of an asymmetric causal relationship between the volatility process inferred from the iTraxx CDS options market and the implied volatility from the stock index options market. We find strong evidence that the stock market leads the CDS market and the effect of the implied stock market volatility is more significant during the volatile regime. We also find that a large jump in the stock return, up or down, may indeed be followed by a regime shift.

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 Ten years have passed since the US-led invasion of Iraq in 2003, and the political scene in Iraq is still blurry. Iraq was promoted to be the democratic example in the Middle East. The US came to Iraq to “create” a democratic system that can be a model for other countries in the region. A major factor in creating such environment is by changing the radical centralised totalitarian regime with a weak state that can give more space to building the civil society in new Iraq (Looney, 2003). Nonetheless, the socio-economic and political indicators of the newly installed political “democratic” system point to notable failures. Apart from poor socio-economic factors, the new political elite has either misused democracy for personal, ethno-sectarian or partisan gains or abused the system to ensure their long lasting presence in the decision making arena. Corruption, disconnection from electorate, poor performance and carelessness of politicians and failing state service provisions have all made citizens question the feasibility of political participation in elections. The electorate seem to have lesser faith in the political parties and blocs whose legitimacy of representation  is at stake. Noticeably, tribes have stepped forward to mobilise people as a non-partisan and independent powerful social structure. They have been active in lobbying the state as well as encouraging their members for active participation. This paper discusses the extent to which Iraqi tribes are involved in political participation. It explores their roles in active citizenship and the way they represent and mobilise their  members. It also probes whether tribes have the influence on shaping the political trajectory in Iraq.

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Contemporary attempts to ‘organise’ risk and manage uncertainty are remaking many ‘industrial-era’ institutions – including maternity hospitals. Health policies are encouraging a shift away from hierarchical, medically dominated structures towards new governance systems and ‘women-centred’ care, often led by midwives. To understand the resulting contestation, in this article we argue for a wider conceptual frame than a focus on neo-liberal state regulation of the professions. We utilise theories of the ‘second modernity’, in particular those concerning socio-cultural changes associated with shifts in risk regimes, to interpret findings from qualitative research studies undertaken in Australian maternity hospitals. Whereas analysis confined to macro or institutional levels emphasises stability and hegemony, we demonstrate that when cultural and interactional levels are examined, considerable fluidity and uncertainty in the identification and negotiation of risk is evident, resulting in new work practices with inevitable shifts in professional identities and allegiances.