Glass Frit Filters for Collecting Metal Oxide Nanoparticles

Filter disks made of glass frit have been found to be effective as means of high-throughput collection of metal oxide particles, ranging in size from a few to a few hundred nanometers, produced in gas-phase condensation reactors. In a typical application, a filter is placed downstream of the reactor and a valve is used to regulate the flow of reactor exhaust through the filter. The exhaust stream includes a carrier gas, particles, byproducts, and unreacted particle-precursor gas. The filter selectively traps the particles while allowing the carrier gas, the byproducts, and, in some cases, the unreacted precursor, to flow through unaffected. Although the pores in the filters are much larger than the particles, the particles are nevertheless trapped to a high degree: Anecdotal information from an experiment indicates that 6-nm-diameter particles of MnO2 were trapped with greater than 99-percent effectiveness by a filtering device comprising a glass-frit disk having pores 70 to 100 micrometer wide immobilized in an 8-cm-diameter glass tube equipped with a simple twist valve at its downstream end

The Tyranny of Time: Knut Hamsun and Aging

Probably no Western writer has so extolled vitality and youth as did the Norwegian Nobel Prize winning novelist Knüt Hamsun. His sympathy for and identity with youth had the natural tandem accompaniment of an extreme revulsion toward old age. His abhorrence of old age and disease are as philosophical positions commonplace. After all, the aging process is what prevents us from ignoring our mortality: it provides us with definite mileposts on our march to the grave. What poet did not protest the transitoriness of all things? Our selves, our environments, are ephemeral; they change and disappear despite our attempts to hold them fast. And although many cultures have equated age with wisdom, who would not prefer to be young than old? But Hamsun did not attack old age or champion youth from an abstract philosophical position. Few writers have had such compelling motivation for an obsession. The reasons for Hamsun\u27s fear and loathing of old age may have been subconscious; perhaps the source accounts for the intensity of the feeling. This essay will establish Hamsun\u27s views on age and trace them back to their origin in the author\u27s own childhood and youthful experiences. The Norwegian\u27s passionate advocacy of youth, his affection for children, and hatred of old age are aspects of a personal revolt. They arose from unforgotten suffering

A case study of the early institutionalization process of a restorative justice social movement organization.

This study investigates the early development process of a restorative justice social movement organization in Louisville, KY. Utilizing social movement and organizational frameworks, this case study seeks to expand knowledge on the early developmental period for small, locally founded social movement organizations. Results from this study confirm claims in the literature about the critical nature of an organization’s structure, networks, and strategy. The analysis also discovers an unexplored strategy for organizational development, i.e. preemptive co-optation. Restorative Justice Louisville deliberatively sought co-optation by the institution they were attempting to change, the juvenile justice system, from early in their development. Due to this strategy, they were able to quickly develop and build legitimacy with those in the justice system. While bearing in mind the organization is still young, these findings raise questions about the benefits of such a strategy and the implications for other social movement organizations

Intrinsic electrochemical activity of single walled carbon nanotube–Nafion assemblies

The intrinsic electrochemical properties and activity of single walled carbon nanotube (SWNT) network electrodes modified by a drop-cast Nafion film have been determined using the one electron oxidation of ferrocene trimethyl ammonium (FcTMA+) as a model redox probe in the Nafion film. Facilitated by the very low transport coefficient of FcTMA+ in Nafion (apparent diffusion coefficient of 1.8 × 10−10 cm2 s−1), SWNTs in the 2-D network behave as individual elements, at short (practical) times, each with their own characteristic diffusion, independent of neighbouring sites, and the response is diagnostic of the proportion of SWNTs active in the composite. Data are analysed using candidate models for cases where: (i) electron transfer events only occur at discrete sites along the sidewall (with a defect density typical of chemical vapour deposition SWNTs); (ii) all of the SWNTs in a network are active. The first case predicts currents that are much smaller than seen experimentally, indicating that significant portions of SWNTs are active in the SWNT–Nafion composite. However, the predictions for a fully active SWNT result in higher currents than seen experimentally, indicating that a fraction of SWNTs are not connected and/or that not all SWNTs are wetted completely by the Nafion film to provide full access of the redox mediator to the SWNT surface

Avatar of transgression: Hamsun's Munken Vendt

Knut Hamsun's play Munken Vendt may be considered a compendium of transgression of many kinds. We see in the play sexual transgression, violence, blasphemy, transgression of social rules (theft, opposition to class divisions), as well as the crossing of boundaries. The protagonist can be seen as an anticipation of the French writer Georges Bataille -- the former Catholic turned libertine fascinated with evil. Aesthetic transgression is evident as well: Hamsun transgressed against rules of style and genre in writing his monstrous eight-act verse play. The play is a confused cry of revolt

Conducting Polymer-Inorganic Nanoparticle (CPIN) Nanoarrays for Battery Applications - Final Technical Report

Our objective was to develop new, self-assembling conducting polymer-inorganic nanoparticle nanoarrays (CPIN nanoarrays) comprised of nanoparticles of inorganic Li+ insertion compounds that are “wired” together with oligomeric chains of derivatives of polythiophene. Using these nanoarrays, we developed an understanding of the relationship between structure and electrochemical function for nanostructured materials. Such nanoarrays are expected to have extremely high specific energy and specific power for battery applications due to the unique structural characteristics that derive from the nanoarray. Under this award we developed several synthetic approaches to producing manganese dioxide nanoparticles (NPs). We also developed a layer-by-layer approach for immobilizing these NPs so they could be examined electrochemically. We also developed new synthetic procedures for encapsulating manganese dioxide nanoparticles within spheres of polyethylenedioxythiophene (PEDOT), a conducting polymer with excellent charge-discharge stability. These have a unique manganese dioxide core-PEDOT shell structure. We examined the structures of these systems using transmission electron microscopy, various scanning probe microscopies, and electrochemical measurements. Various technical reports have been submitted that describe the work, including conference presentations, publications and patent applications. These reports are available through http://www.osti.gov, the DOE Energy Link System

Effects of Electron Exchange on the Photochemical, Electrochemical and Electrocatalytic Responses of Polymer Modified Electrodes

A spectroelectrochemical method is presented which may be used to measure the concentrations of the two oxidation states of a redox couple in a polymer film. The method is applied to Ru(bpy)32+ in Nafion films on transparent tin oxide electrodes. Measurements of the emission of this complex in Nafion films on graphite and tin oxide electrodes are used to obtain information about the quenching of Ru(bpy)32+* by Ru(bpy)33+. Features of the luminescence which yield insight into the structure of the Nafion film are discussed. Experiments are described which bear on the question of when electron self-exchange reactions can contribute to the propagation of electrons through polymer films on electrodes. The results of experiments on the Co(bpy)32+/+ couple are discussed in terms of a theory derived by Dahms and Ruff et al. which describes the contribution of electron self-exchange reactions to diffusion in mixtures containing both halves of a redox couple. The propagation of charge through polymer films by electron exchange cross-reactions between different redox couples which are co-incorporated into a polymer film on an electrode is discussed. Two experimental examples of this phenomenon are presented. An electrocatalytic application of a polymer modified electrode is described. Cobalt tetraphenylporphyrin is incorporated into a Nafion film on a graphite electrode, and this porphyrin is used to catalyze the two-electron electroreduction of dioxygen. Enhanced catalytic currents are observed when an electron mediator (Ru(NH3)63+) is added to the film. This mediator serves to shuttle electrons between the electrode and the relatively immobile catalyst sites. The performance of electrocatalysts in polymer films is discussed with emphasis on ways to enhance stability without sacrificing efficiency.</p

Connections Network: Harnessing the Collective Influence of Grassroots Leaders to Address Health-Related Problems in Hawkins and Hancock County, TN

In March 2021, grassroots leaders in two counties in northeast Tennessee formed a new network called Connections. Leaders are working to strengthen the capacity of the network and member organizations by promoting partnerships as vital to address effectively rural social determinants of health. Connections provides network members with capacity-building tools and resources, including two funding opportunities, to achieve their missions and sustain impact. Network members are also aligning around common goals to address the socioeconomic conditions affecting health outcomes. Connections will utilize findings from network activities and collaborations to identify synergies that can accelerate improvements in community health and well-being

Use of Conducting Polymers for Electronic Communication with Redox Active Nanoparticles

Nanoscale materials provide unique properties that will enable new technologies and enhance older ones. One area of intense activity in which nanoscale materials are being used is in the development of new functional materials for battery applications.1-4 This effort promises superior materials with properties that circumvent many of the problems associated with traditional battery materials. Previously we have worked on several approaches for using nanoscale materials for application as cathode materials in rechargeable Li batteries.5-11 Our recent work has focused on synthesizing MnO2 nanoparticles and using conducting polymers to electronically address these particles in nanoparticle assemblies. This presentation will focus on those efforts. MnO2 nanoparticles that are encapsulated with poly(3,4-ethylenedioxythiophene) (PEDOT) are prepared using 3,4-ethylenedioxythiophene (EDOT) as a chemical reductant for permanganate anion. This non-aqueous preparation is based on a recent report of a similar method for preparation of PEDOT-encapsulated Au nanoparticles.12 We also describe the synthesis of MnO2 colloidal nanoparticles prepared using an aqueous route involving reduction of permanganate anion with butanol using a previously described route.13 We report the synthesis and characterization of the PEDOT material, and the aqueous colloidal material. We show that the aqueous colloidal nanoparticles can be trapped in thin films using a layer-by-layer deposition approach, and that these films are both redox active and exhibit kinetically facile electrochemical responses. This is illustrated in Figure 1 below, which shows cyclic voltammetry of MnO2 colloidal nanoparticles entrapped in a thin film at an ITO electrode surface using poly(diallyldimethylammonium chloride (PDDA). Finally, we report on the use of X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) to characterize the oxidation state and coordination environment around Mn in these materials