Growing Surface Tension of Amorphous-Amorphous Interfaces on Approaching the Colloidal Glass Transition

There is mounting evidence indicating that relaxation dynamics in liquids approaching their glass transition not only becomes increasingly cooperative (1,2) but the relaxing regions also become more compact in shape(3-7). While the surface tension of the interface separating neighboring relaxing regions is thought to play a crucial role in deciding both their size and morphology(8-10), owing to the amorphous nature of these regions, even identifying these interfaces has not been possible in bulk liquids. Here, by devising a scheme to identify self-induced disorder sites in bulk colloidal liquids, we directly quantified the dynamics of interfaces delineating regions of high and low configurational overlap. This procedure also helped unveil a non-monotonicity in dynamical correlations that has never been observed in bulk supercooled liquids. Using the capillary fluctuation method (11,12), we measured the surface tension of amorphous-amorphous interfaces with supercooling and find that it increases rapidly across the mode-coupling area fraction. Remarkably, a similar growth in the surface tension is also seen in the presence of a pinned amorphous wall. Our observations help prune theories of glass formation and opens up new research avenues aimed at tuning the properties of amorphous-amorphous interfaces, and hence the glass itself, in a manner analogous to grain boundary engineering in polycrystals (13)

Light scattering from a magnetically tunable dense random medium with weak dissipation : ferrofluid

We present a semi-phenomenological treatment of light transmission through and its reflection from a ferrofluid, which we regard as a magnetically tunable system of dense random dielectric scatterers with weak dissipation. Partial spatial ordering is introduced by the application of a transverse magnetic field that superimposes a periodic modulation on the dielectric randomess. This introduces Bragg scattering which effectively enhances the scattering due to disorder alone, and thus reduces the elastic mean free path towards Anderson localization. Our theoretical treatment, based on invariant imbedding, gives a simultaneous decrease of transmission and reflection without change of incident linear polarisation as the spatial order is tuned magnetically to the Bragg condition, namely the light wave vector being equal to half the Bragg vector (Q). Our experimental observations are in qualitative agreement with these results. We have also given expressions for the transit (sojourn) time of light and for the light energy stored in the random medium under steady illumination. The ferrofluid thus provides an interesting physical realization of effectively a "Lossy Anderson-Bragg" (LAB) cavity with which to study the effect of the interplay of spatial disorder, partial order and weak dissipation on light transport. Given the current interest in propagation, optical limiting and storage of light in ferrofluids, the present work seems topical

Photoluminescence and EPR studies of ZnS nanoparticles Co-doped with Mn and Te

ZnS nanoparticles Co-doped with Mn and Te (x = 0.05 and 0.10) have been synthesized for the first time by chemical co-precipitation method, thiophenol is used to passivate the surface of the particles. The as-prepared samples were amorphous in nature. Nanocrystallinity was induced after calcining the samples at 300oC/2hrs. The obtained nanoparticles were subjected to X-ray diffraction (XRD), Energy Dispersive Analysis of X-rays (EDAX), Transmission Electron Microscopy (TEM), hotoluminescence (PL) and Electron Paramagnetic Resonance (EPR) studies. All the samples exhibited cubic structure and the particle size was found to be 3-5 nm. EDAX revealed that the compositions did not deviate much from the target compositions. The photoluminescence studies showed emission in the red region and the emission wavelength is varied with composition. The Electron Paramagnetic Resonance (EPR) spectra showed paramagnetic nature of the samples at room temperature. EPR and PL results were quite consistent with each other. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2197

How the timing of police evidence disclosure impacts custodial legal advice

Presently, the police in England and Wales disclose their evidence at different points during the arrest and detention of a suspect. While the courts have not objected to this, past field research suggests that lawyers can only advise their clients accurately when the police disclose their evidence before the police interview. To examine this from a law – psychology perspective, we recruited 100 criminal defence lawyers to participate in an online study. Lawyers read fictional scenarios and provided custodial legal advice to a hypothetical client (Christopher) when given either pre-interview disclosure or disclosure at various points during the police interview (early, gradually, or late). Lawyers given pre-interview disclosure provided considerably more informed legal advice compared to those who were only provided with disclosure during the hypothetical police interview. Using an interdisciplinary approach, this paper provides further evidence that pre-interview disclosure is essential for lawyers to deliver case-specific legal advice to suspects

Behind closed doors : live observations of current police station disclosure practices and lawyer-client consultations

Drawing on recent observational fieldwork as well as existing research studies in the fields of law and of psychology, this article examines the nature of police practices in the disclosure of evidence before and during custodial interviews of legally represented suspects. Whilst police pre-interview disclosure to lawyers was a fixed practice, the format of disclosure varied and lawyers were rarely permitted to inspect the evidence, relying instead on the officer’s account. Disclosure was sometimes provided in stages, either as a deliberate tactic or when evidence was lacking. Officers occasionally exaggerated the strength of their case to suspects and resisted providing more detail to lawyers – an approach that seemed designed to elicit an admission from the suspect. In line with past research, lawyers relied on the evidence that police disclosed when advising clients before the interview and occasionally argued with the police for more disclosure. Taken together, these findings suggest that police are complying with the minimum disclosure requirements set out by legislation, and that police may be more open with lawyers than previous research suggests. Some of our findings warrant concern, however, and raise questions about risks to vulnerable suspects in custody and risks to suspects without legal representation

Strategic disclosure of evidence : perspectives from psychology and law

The police frequently present their evidence to suspects in investigative interviews. Accordingly, psychologists have developed strategic ways in which the police may present evidence to catch suspects lying or to elicit more information from suspects. While research in psychology continues to illustrate the effectiveness of strategic evidence disclosure tactics in lie detection, lawyers and legal research challenge these very tactics as undermining fair trial defense rights. Legal research is alive to the problems associated with strategically disclosing evidence to a suspect, such as preventing lawyers from advising the suspect effectively, increasing custodial pressure for the suspect, and worsening working relations between lawyers and police. This paper brings together the opposing research and arguments from the two disciplines of psychology and law, and suggests a new way forward for future research and policy on how the police should disclose evidence

Truth-tellers stand the test of time and contradict evidence less than liars, even months after a crime

When deceptive suspects are unaware of the evidence the police hold against them, they contradict that evidence more than truthful suspects do – a useful cue to deception. But given that, over time, truthful suspects might forget the past and also contradict the evidence, how effective are lie detection techniques that rely on such inconsistencies when suspects are questioned months after a crime? In Experiment 1, people committed a theft (liars) or a benign activity (truth-tellers) in a university bookshop. Shortly after or two months later, we questioned them about their bookshop visit without informing them of the evidence implicating them in the theft. Though truth-tellers contradicted some evidence after both time delays, liars always contradicted the evidence more than did truth-tellers. In Experiment 2, we presented the mock suspects’ responses to an independent group of laypeople and asked them to rate how deceptive the suspects were. Laypeople rated liars as more deceptive than truth-tellers after both time delays, but also rated truth-tellers questioned two months after the crime as more deceptive than truth-tellers questioned shortly after the crime. These findings suggest that liars’ tendency to distance themselves from a crime might outweigh any memory decay that truth-tellers experience in the two months following a crime. As a result, the extent of a suspect’s contradictions with the evidence could still be diagnostic of deception even after an extended time delay