125 research outputs found
Extremal Graphs for Intersecting Triangles
AbstractIt is known that for a graph on n vertices [n2/4] + 1 edges is sufficient for the existence of many triangles. In this paper, we determine the minimum number of edges sufficient for the existence of k triangles intersecting in exactly one common vertex
Precipitation and Hydrolysis of Metallic Ions. III. Studies on the Solubility of Yttrium and Some Rare Earth Hydroxides
The solubility limits of lanthanum, praseodymium, neodymium,
samarium, gadolinium, dysprosium , erbium, ytterbium, lutetium, and
yttrium hydroxides hav e been determined by tyndallometric and
pH measurements. The solubility products (log Kso) of these rare
earth hydroxides were determined from the solubility limits by a
simple graphical method. The predominant soluble species are free
or hydrated Ln3+ ions in equilibrium with the formed solid phase.
Since no other step of hydrolysis is evident from the solubility limits,
the reaction for the formation of Ln(OH)3 precipitate may be
written as:
Ln+a + 3 Off -Z Ln(OH)a (s)
The graphically obtained precipitation pH values (C0 ) and the
values calculated for the solubility product (log Ks0 ) indicate that
the basicities of the rare earth elements decrease in the following
order:
La, Pr, Nd, Sm, Er, Gd, Yb, Lu, and Y
The solubility products of th e se rare earth hydroxides have
values ranging from 10-"5 ·1 to 10 ·1 9-9
Adiabatic Quantum Computing for Random Satisfiability Problems
The discrete formulation of adiabatic quantum computing is compared with
other search methods, classical and quantum, for random satisfiability (SAT)
problems. With the number of steps growing only as the cube of the number of
variables, the adiabatic method gives solution probabilities close to 1 for
problem sizes feasible to evaluate via simulation on current computers.
However, for these sizes the minimum energy gaps of most instances are fairly
large, so the good performance scaling seen for small problems may not reflect
asymptotic behavior where costs are dominated by tiny gaps. Moreover, the
resulting search costs are much higher than for other methods. Variants of the
quantum algorithm that do not match the adiabatic limit give lower costs, on
average, and slower growth than the conventional GSAT heuristic method.Comment: added discussion of discrete adiabatic method, and simulations with
30 bits 8 pages, 8 figure
Third World gap year projects: Youth transitions and the mediation of risk
This is the post-print version of the final published article. The definitive, peer-reviewed and edited version of this article is available from the link below. Copyright @ 2008 Pion.In recent years in the UK there has been a great expansion in the number of young people travelling to Third World countries between school and university in order to participate as volunteers on structured gap year projects. Travel to such places is commonly perceived as âriskyâ, and takes young people outside the protective cocoon of UK health and safety legislation. One of the functions played by the providers of gap year projects is to mediate risk. On the basis of analysis of promotional literature, interviews with organisers of gap year projects, and focus groups of returned volunteers, in this paper I argue that the various strategies of risk mediation undertaken by gap year providers serve to reconcile modernising tendencies in UK society toward risk control and structure with postmodern inclinations towards individualisation and uncertainty
Does the Supreme Court Follow the Economic Returns? A Response to A Macrotheory of the Court
Today, there is a widespread idea that parents need to learn how to carry out their roles as parents. Practices of parental learning operate throughout society. This article deals with one particular practice of parental learning, namely nanny TV, and the way in which ideal parents are constructed through such programmes. The point of departure is SOS family, a series broadcast on Swedish television in 2008. Proceeding from the theorising of governmentality developed in the wake of the work of Michel Foucault, we analyse the parental ideals conveyed in the series, as an example of the way parents are constituted as subjects in the âadvanced liberal societyâ of today. The ideal parent is a subject who, guided by the coach, is constantly endeavouring to achieve a makeover. The objective of this endeavour, however, is self-control, whereby the parents will in the end become their own coaches.
Thin film composite membranes with regulated crossover and water migration for long-life aqueous redox flow batteries.
Redox flow batteries (RFBs) are promising for large-scale long-duration energy storage owing to their inherent safety, decoupled power and energy, high efficiency, and longevity. Membranes constitute an important component that affects mass transport processes in RFBs, including ion transport, redox-species crossover, and the net volumetric transfer of supporting electrolytes. Hydrophilic microporous polymers, such as polymers of intrinsic microporosity (PIM), are demonstrated as next-generation ion-selective membranes in RFBs. However, the crossover of redox species and water migration through membranes are remaining challenges for battery longevity. Here, a facile strategy is reported for regulating mass transport and enhancing battery cycling stability by employing thin film composite (TFC) membranes prepared from a PIM polymer with optimized selective-layer thickness. Integration of these PIM-based TFC membranes with a variety of redox chemistries allows for the screening of suitable RFB systems that display high compatibility between membrane and redox couples, affording long-life operation with minimal capacity fade. Thickness optimization of TFC membranes further improves cycling performance and significantly restricts water transfer in selected RFB systems
Thin Film Composite Membranes with Regulated Crossover and Water Migration for Long-Life Aqueous Redox Flow Batteries
Redox flow batteries (RFBs) are promising for large-scale long-duration energy storage owing to their inherent safety, decoupled power and energy, high efficiency, and longevity. Membranes constitute an important component that affects mass transport processes in RFBs, including ion transport, redox-species crossover, and the net volumetric transfer of supporting electrolytes. Hydrophilic microporous polymers, such as polymers of intrinsic microporosity (PIM), are demonstrated as next-generation ion-selective membranes in RFBs. However, the crossover of redox species and water migration through membranes are remaining challenges for battery longevity. Here, a facile strategy is reported for regulating mass transport and enhancing battery cycling stability by employing thin film composite (TFC) membranes prepared from a PIM polymer with optimized selective-layer thickness. Integration of these PIM-based TFC membranes with a variety of redox chemistries allows for the screening of suitable RFB systems that display high compatibility between membrane and redox couples, affording long-life operation with minimal capacity fade. Thickness optimization of TFC membranes further improves cycling performance and significantly restricts water transfer in selected RFB systems
Psychopolitics: Peter Sedgwickâs legacy for mental health movements
This paper re-considers the relevance of Peter Sedgwick's Psychopolitics (1982) for a politics of mental health. Psychopolitics offered an indictment of âanti-psychiatryâ the failure of which, Sedgwick argued, lay in its deconstruction of the category of âmental illnessâ, a gesture that resulted in a politics of nihilism. âThe radical who is only a radical nihilistâ, Sedgwick observed, âis for all practical purposes the most adamant of conservativesâ. Sedgwick argued, rather, that the concept of âmental illnessâ could be a truly critical concept if it was deployed âto make demands upon the health service facilities of the society in which we liveâ. The paper contextualizes Psychopolitics within the âcrisis tendenciesâ of its time, surveying the shifting welfare landscape of the subsequent 25 years alongside Sedgwick's continuing relevance. It considers the dilemma that the discourse of âmental illnessâ â Sedgwick's critical concept â has fallen out of favour with radical mental health movements yet remains paradigmatic within psychiatry itself. Finally, the paper endorses a contemporary perspective that, while necessarily updating Psychopolitics, remains nonetheless âSedgwickianâ
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