Glassy states in a shaken sandbox

Our model of shaken sand, presented in earlier work, has been extended to include a more realistic `glassy' state, i.e., when the sandbox is shaken at very low intensities of vibration. We revisit some of our earlier results, and compare them with our new results on the revised model. Our analysis of the glassy dynamics in our model shows that a variety of ground states is obtained; these fall in two categories, which we argue are representative of regular and irregular packings.Comment: 10 pages. 3 figures. To appear in Proceedings of Research Workshop on "Challenges in Granular Physics" (ICTP, Trieste, August 7-11, 2001). Special issue of Advances in Complex System

Spin-models of granular compaction: From one-dimensional models to random graphs

We discuss two athermal types of dynamics suitable for spin-models designed to model repeated tapping of a granular assembly. These dynamics are applied to a range of models characterised by a 3-spin Hamiltonian aiming to capture the geometric frustration in packings of granular matter.Comment: Contribution to "Challenges in Granular Media", ICTP Trieste; to appear in 'Advances in Complex Systems

Microplastics Degradation and Characterization

In the last decade, issues related to pollution from microplastics in all environmental compartments and the associated health and environmental risks have been the focus of intense social, media, and political attention worldwide. The assessment, quantification, and study of the degradation processes of plastic debris in the ecosystem and its interaction with biota have been and are still the focus of intense multidisciplinary research. Plastic particles in the range from 1 to 5 mm and those in the sub-micrometer range are commonly denoted as microplastics and nanoplastics, respectively. Microplastics (MPs) are being recognized as nearly ubiquitous pollutants in water bodies, but their actual concentration, distribution, and effects on natural waters, sediments, and biota are still largely unknown. Contamination by microplastics of agricultural soil and other environmental areas is also becoming a matter of concern. Sampling, separation, detection, characterization and evaluating the degradation pathways of micro- and nano-plastic pollutants dispersed in the environment is a challenging and critical goal to understand their distribution, fate, and the related hazards for ecosystems. Given the interest in this topic, this Special Issue, entitled “Microplastics Degradation and Characterization”, is concerned with the latest developments in the study of microplastics

Towards the Glass Transition in Vibrated Granular Matter

Granular materials are large sets of macroscopic particles that interact solely via contact forces. The static behavior depends on the contact network and on the surface friction forces between grains; when they are set in motion (typically by vibrations) their dynamics is dominated by inelastic collisions. For these reasons granular media show an extremely rich phenomenology, ranging from fluid-like properties (if strongly vibrated), to "jamming", glassy, behavior (if weakly vibrated), to aging and hysteretical phenomena observed when they become trapped in frozen, amorphous states. The objective of this work is to study these states and transitions, and to characterize the analogies found between the dynamic behavior of vibrated granular media and the glass transition observed in thermal glass-formers. These analogies justify the interest in granular materials, because granular media can be seen as simplified model systems useful in the study of out of equilibrium thermodynamics, and, in general, to the larger framework known as "complexity". The granular materials considered here are composed of spheric, polished glass spheres. Since the surface state plays an important role in the grain-grain interaction, some measurements were also performed with acid etched beads, having different surface roughness. The samples are vertically vibrated to achieve vibrofluidization. Different kinds of vibration are used, to highlight different properties of the system. We first consider the transition between the fluid and the subcooled glassy phase, using different experimental techniques. The most important one is a torsion oscillator, that interacts with the granular media via immersed probes. The torsion oscillator can be used in forced mode. A torque is applied on the probe, and we measure the mechanical response function (complex susceptibility). In general, a relaxation is found and it is interpreted as the signature of the irreversible energy loss (damping) in granular collisions. This relaxation has an intrinsic time scale, and systematic analysis of it shows that a clear parallel can be traced to the behavior of "strong" glasses. In particular, it is found that (i) the relaxation time is a function of a unified control parameter, proportional to the square root of the average vibration, and phenomenologically equivalent to an effective temperature; (ii) the functional form with which the relaxation times approach the final "frozen" state has an Arrhenius, or Vögel-Fulcher-Tamman (VFT) behavior. The same torsion oscillator is employed in free mode. In this case, no external torque is applied, and the probe moves adapting its position under the effect of the continuous rearrangements in the sample. The system is studied by computing the power spectral density of the (angular position) time series. The resulting spectra represent a "configurational noise" as the system randomly hops from one configuration to the following. This allows to define, using a completely different approach, the same intrinsic time scale observed in forced mode measurements. The comparison of the two techniques allows to obtain a more complete and detailed picture of the dynamics in the jamming region. From this comparison, it was inferred that the system is also influenced by an effective vibration frequency, and that the relaxation time has indeed a non-Arrhenius behavior as a function of a control parameter defined as as = √ Γ/ωs. A model was developed combining rheological observations to a statistic approach describing extremal phenomena. This model justifies the appearance of both the control parameter and the VFT evolution of the relaxation. Furthermore, the model is predictive and exposes the effect of a few other rheologic properties of granular system. The effect of surface roughness are considered, showing that the static and dynamic surface friction coefficients are well described by the model. A second relevant part of this work is devoted to an explicit verification that macroscopic probes act as Brownian objects. This fact is often used to interpret experimental data (also in the present work) and to propose theoretical model. However, no explicit evidence has ever been discussed. This is hard to do, using a constrained system such as the torsion oscillator, because the restoring coefficient influences the dynamics of diffusion. To overcome the problem we built a different apparatus, called "Brownian motor", where the probes are mounted on ball bearings, so that they are free to turn without constraint. The properties of the time series of the position of the free turning probe and of the torsionally constrained oscillator can finally be analyzed and compared with simple simulations. The data show an overall diffusion-like behavior, that is influenced by the presence of constraints. Using fractal analysis we estimate the diffusion, or Hurst exponent. This allows to verify that a "macroscopic" object (the probe) immersed in the "microscopic" granular medium indeed behaves as a Brownian object, and that its dynamics can be studied in detail, showing that it undergoes anomalous diffusion. This work is concluded with a discussion on a few possible developments. The most promising idea is a novel approach to the study of the geometrical properties of the contact network of granular assemblies, that is responsible for many of the properties of the granular sample. By using Magnetic Resonance Imaging, the static 3-D structure of granular media can be reconstructed with unprecedented accuracy, resolution and ease of reproducibility. From the spatial information we can extract all the properties of static granular media: the compaction factor, the grain-grain correlation function, the free volume and other observables. Systematic studies could allow experimental confirmations of the many theoretical models that have been proposed in the last years and that still lack a thorough comparison with experiments. This idea does not conclude the perspectives of this work, that are vast and intriguing. A few promising subjects are reviewed more into detail in the corresponding Perspective section. To name a few we cite: measurements of induced aging in non-vibrated samples, the Brownian motor, stick and slip phenomena and their comparison with earthquakes

Havening

Havening explores, through the creative nonfiction genre, the life and work of horticulturist-philosopher Liberty Hyde Bailey, Jr. (1858-1854), the life experiences of the present author, and the small hometown of South Haven that they both share. It presents the tension of living a life that strives to balance academicism with creativity and energy, and pushes the question of Bailey\u27s relevance as a voice for our time. This monograph is primarily an artwork, not a scholarly paper

Reading Chernobyl: Psychoanalysis, Deconstruction, Literature

This thesis explores the psychological trauma of the survivors of the Chernobyl nuclear disaster, which occurred on April 26, 1986. I argue for the emergence from the disaster of three Chernobyl traumas, each of which will be analysed individually – one per chapter. In reading these three traumas of Chernobyl, the thesis draws upon and situates itself at the interface between two primary theoretical perspectives: Freudian psychoanalysis and the deconstructive approach of Jacques Derrida. The first Chernobyl trauma is engendered by the panicked local response to the consequences of the explosion at Chernobyl Reactor Four by the power plant’s staff, the fire fighters whose job it was to extinguish the initial blaze caused by the blast, the inhabitants of nearby towns and villages, and the soldiers involved in the region’s evacuation and radiation decontamination. Most of these people died from radiation poisoning in the days, weeks, months or years after the disaster’s occurrence. The first chapter explores the usefulness and limits of Freudian psychoanalytic readings of local survivors’ testimonies of the disaster, examining in relation to the Chernobyl event Freud’s practice of locating the authentic primal scene or originary traumatic witnessing experience in his subjects’ pasts, as exemplified by his Wolf Man analysis, detailed in his psychoanalytic study ‘On the History of an Infantile Neurosis’ (1918). The testimonies read through this Freudian psychoanalytic lens are constituted by Igor Kostin’s personal account of the disaster’s aftermath, detailed in his book Chernobyl: Confessions of a Reporter (2006), and by Svetlana Alexievich’s interviews with Chernobyl disaster survivors in her book Voices from Chernobyl: The Oral History of a Nuclear Disaster (2006). The second chapter argues that Freudian psychoanalysis only provides a provisional, ultimately fictional origin of Chernobyl trauma. Situating itself in relation to trauma studies, this thesis, progressing from its first to its second chapter, charts the geographical and temporal shift between these first and second traumas, from trauma-as-sudden-event to trauma-as-gradual-process. In the weeks following the initial Chernobyl explosion, which released into the atmosphere a radioactive cloud that blew in a north-westerly direction across Northern Ukraine, Belarus, Latvia, Estonia, Finland and Sweden, symptoms of radiation poisoning slowly emerged in the populations of the abovementioned countries. To analyse the psychological impact of confronting this gradual, international unfolding of trauma – the second trauma of Chernobyl – the second chapter of this thesis explores the critique of the global attempt to archivise, elegise and ultimately understand the Chernobyl disaster in Mario Petrucci’s elegies, compiled in his poetry collection Heavy Water: A Poem for Chernobyl (2006), the horror film Chernobyl Diaries (2012, dir. Bradley Parker), and Adam Roberts’ Science Fiction novel, Yellow Blue Tibia (2009). Analysing the deconstructive approach of Jacques Derrida in these texts – his notions of archive fever, impossible mourning and ethical mourning – this chapter argues that the attempt to interiorise, memorialise and mourn the survivors of the Chernobyl disaster is narcissistic, hubristic and violent in the extreme. It then proposes that Derrida’s notion of ethical mourning, outlined most clearly in his lecture ‘Mnemosyne’ (1984), enables us to situate our emotional sympathy for survivors – who, following Derrida’s lecture, are maintained as permanently exterior and inaccessible to us – in our very inability or failure to comprehend or locate the origin of their Chernobyl traumas. The third and final chapter analyses the third trauma of Chernobyl: the psychological and physiological effects of the disaster on second-generation inhabitants living near the Exclusion Zone erected around the evacuated, cordoned-off and still-radioactive Chernobyl region. These second-generation experiences of living near a sealed-away source of intense radiation are reconstructed in literature and videogaming: in Darragh McKeon’s novel All That Is Solid Melts Into Air (2014), Hamid Ismailov’s novel The Dead Lake (2014) and the videogame S.T.A.L.K.E.R: Shadow of Chernobyl (2007), developed by the company GSC Game World. The analysis of these texts is informed by Nicolas Abraham and Maria Torok’s psychoanalytic theory of the intergenerational phantom: the muteness of a generation’s history which returns to haunt the succeeding generations. This chapter will explore the psychological effects upon second-generation Chernobyl survivors, which result from these survivors’ incorporation or unconscious interiorisation of their parents’ psychologically repressed traumatic Chernobyl experiences, by analysing reconstructions of this process in the abovementioned texts. These parental experiences, echoing the Exclusion Zone as a denied physical space, have been interred in inaccessible psychic crypts. By way of conclusion, the thesis then offers an alternative theory of reading survivors’ Chernobyl trauma. Survivors’ restaging of their Chernobyl witnessing experiences as jokes enables them to cathartically, temporarily abreact their trauma through the laughter that these jokes engender

Remedial methods for the correction of stammering and stuttering for use in grades nine to twelve

Thesis (Ed.M.)--Boston University, 1947. This item was digitized by the Internet Archive

The Empathy Project: A Novel

Senior Project submitted to The Division of Languages and Literature of Bard College