Performance evaluation and characterization of symmetric capacitors with carbon black, and asymmetric capacitors using a carbon foam supported nickel electrode

This thesis evaluates a novel asymmetric capacitor incorporating a carbon foam supported nickel hydroxide positive electrode and a carbon black negative electrode. A series of symmetric capacitors were prepared to characterize the carbon black (CB) negative electrode. The influence of the binder, PTFE, content on the cell properties was evaluated. X-ray diffraction characterization of the nickel electrode during cycling is also presented. The 3 wt% and 5 wt% PTFE/CB symmetric cells were examined using cyclic voltammetry (CV) and constant current charge/discharge measurements. As compared with symmetric cells containing more PTFE, the 3 wt% cell has the highest average specific capacitance, energy density and power density over 300 cycles, 121.8 F/g, 6.44 Wh/kg, and 604.1 W/kg, respectively. Over the 3 to 10 wt% PTFE/CB range, the 3 wt% sample exhibited the lowest effective resistance and the highest BET surface area. Three asymmetric cells (3 wt% PTFE/CB negative electrode and a nickel positive) were fabricated; cycle life was examined at 3 current densities. The highest average energy and power densities over 1000 cycles were 20 Wh/kg (21 mA/cm2) and 715 W/kg (31 mA/cm2), respectively. The longest cycle life was 11,505 cycles (at 8 mA/cm2), with an average efficiency of 79% and an average energy density of 14 Wh/kg. The XRD results demonstrate that the cathodically deposited nickel electrode is a typical α-Ni(OH)2 with the R3m structure (ABBCCA stacking); the charged electrodes are 3γ-NiOOH with the same stacking as the α-type; the discharged electrodes (including as-formed electrode) are aged to β’-Ni(OH)2 (a disordered β) with the P3m structure (ABAB stacking). A 3γ remnant was observed.

Interrogating the spaces of personal photography : women, identity, and the cultural formation of photographic practice

Personal photographs permeate our lives from the moment we are born as they define who we are within our familial group and local communities. Archived in family albums or framed on living room walls, they continue on after our death as mnemonic artifacts referencing our gendered, raced, and ethnic identities. This dissertation examines salient instances of what women “do” with personal photographs, not only as authors and subjects but also as collectors, archivists, and family and cultural historians. This project seeks to contribute to more productive, complex discourse about how women form relationships and engage with the conventions and practices of personal photography. In the first part of this dissertation I revisit developments in the history of personal photography, including the advertising campaigns of the Kodak and Agfa Girls and the development of albums such as the Stammbuch and its predecessor, the carte-de-visite, that demonstrate how personal photography has functioned as a gendered activity that references family unity, sentimentalism for the past, and self-representation within normative familial and dominant cultural groups, thus suggesting its importance as a cultural practice of identity formation. The second and primary section of the dissertation expands on the critical analyses of Gillian Rose, Patricia Holland, and Nancy Martha West, who propose that personal photography, marketed to and taken on by women, double-exposes their gendered identities. Drawing on work by critics such as Deborah Willis, bell hooks, and Abigail Solomon-Godeau, I examine how the reconfiguration, recontextualization, and relocation of personal photographs in the respective work of Christine Saari, Fern Logan, and Katie Knight interrogates and complicates gendered, raced, and ethnic identities and cultural attitudes about them. In the final section of the dissertation I briefly examine select examples of how emerging digital spaces on the Internet function as a site for personal photography, one that both reinscribes traditional cultural formations while offering new opportunities for women for the display and audiencing of identities outside the family.

Differential optical densities of intraretinal spaces

PURPOSE: To test the hypothesis that hyporeflective spaces in the neuroretina found on optical coherence tomography (OCT) examination have different optical reflectivities according to whether they are associated with exudation or degeneration. METHODS: Retrospective analysis of eyes with idiopathic perifoveal telangiectasia (IPT), diabetic macular edema (DME), idiopathic central serous chorioretinopathy (CSC), retinitis pigmentosa (RP), or cone dystrophy (CD) and eyes of healthy control subjects. OCT scans were performed. Raw scan data were exported and used to calculate light reflectivity profiles. Reflectivity data were acquired by projecting three rectangular boxes, each 50 pixels long and 5 pixels wide, into the intraretinal cystoid spaces, centrally onto unaffected peripheral RPE, and onto the prefoveolar vitreous. Light reflectivity in the retinal pigment epithelium (RPE), vitreous, and intraretinal spaces for the different retinal conditions and control subjects were compared. RESULTS: Reflectivities of the vitreous and the RPE were similar among the groups. Hyporeflective spaces in eyes with exudation (DME, RP, and CSC) had higher reflectivity compared with the mean reflectivity of the vitreous, whereas the cystoid spaces in the maculae of the eyes without exudation (CD and IPT) had a lower reflectivity than did the normal vitreous. CONCLUSIONS: Analysis of the light reflectivity profiles may be a tool to determine whether the density of hyporeflective spaces in the macula is greater or less than that of the vitreous, and may be a way to differentiate degenerative from exudative macular disease.

Perivascular spaces and the two steps to neuroinflammation

Immune cells enter the central nervous system (CNS) from the circulation under normal conditions for immunosurveillance and in inflammatory neurologic diseases. This review describes the distinct anatomic features of the CNS vasculature that permit it to maintain parenchymal homeostasis and which necessitate specific mechanisms for neuroinflammation to occur. We review the historical evolution of the concept of the blood-brain barrier and discuss distinctions between diffusion/transport of solutes and migration of cells from the blood to CNS parenchyma. The former is regulated at the level of capillaries, whereas the latter takes place in postcapillary venules. We summarize evidence that entry of immune cells into the CNS parenchyma in inflammatory conditions involves 2 differently regulated steps: transmigration of the vascular wall into the perivascular space and progression across the glia limitans into the parenchyma.

Blighted Spaces and the Politics of Everyday Life

While a great deal is known about the demographic and historical trends that shape the built environment of American cities, much less is known about the politics of everyday life among residents who continue to live in postindustrial neighborhoods. This study seeks to compensate for the current gaps in academic research by conducting spatially informed ethnography in a North Philadelphia community. Specifically, the study will explore the issue of urban "blight" from a cultural geography perspective, primarily by looking at the ways in which "blighted" spaces shape everyday life, and everyday life in turn shapes and produces the spatial environment. In response to these concerns, my study poses the questions: What would it mean to focus on the ways in which human agency, imagination, and subjectivity are shaped by "blighted" geographical locations? What would it mean to pay ethnographic attention to how subjects in given historical conditions are shaped by "blighted" spaces, as well as how they respond to these spaces in culturally specific ways? By incorporating critical interdisciplinary approaches, this study offers a new way of looking at the various practices of daily life - including flexible, informal economic activities and post-welfare related "lifestyles" of resistance. Through the lens of spatial ethnography, the study seeks to elucidate the ways in which postindustrial space interacts with culture, poverty and addiction; as well as the ways in which users continue to appropriate postindustrial spaces in culturally meaningful ways under the aegis of the semi-welfare state.

Educational and Anthropological Perspectives: An Italian View on Migration in Multi-cultural Urban Spaces

In contemporary societies there are different ways to perceive the relation between identity and alterity and to describe the difference between “us” and “them”, residents and foreigners. Anthropologist Sandra Wallman sustains that in multi-cultural urban spaces the frontiers of diversity are not only burdensome markers of identity, but rather they could also represent new chances to define “identity” and “alterity”. These frontiers, in fact, can work like interfaces through which to build time after time, in a creative way, a relationship with the other. From this point of view, the concept of boundary can offer many opportunities to creatively define the relation with the other and to sign new options for cognitive and physical movement. On the other side, in many cases we have a plenty of mechanisms of exclusion that transforms a purely empirical distinction between “us” and “them” in an ontological contrast, as in the case when the immigrant undergoes hostilities through discriminatory language. Even though these forms of racism are undoubtedly objectionable from a theoretical point of view, they are anyway socially “real”, in the sense that they are perpetually reaffirmed and strengthened in public opinion. They are in fact implicit “truths”, realities that are considered objective, common opinions that are part of day-to-day existence. That is the reason why an anthropological prospective including the study of “common sense” should be adopted in our present day studies on migration, as pointed out by American anthropologist Michael Herzfeld. My primary goal is to analyze with such a critical approach same pre-conditions of racism and exclusion in contemporary multi-cultural urban spaces. On the other hand, this essay would also investigate positive strategies of comparing, interchanging, and negotiating alterity in social work. I suggest that this approach can offer positive solutions in coping with “diversity” and in working out policies for recognizing a common identity which, at the same time, do not throw away the relevance of political and economic power.

Efficient Bimanual Symmetric 3D Manipulation for Bare-Handed Interaction

Recently, stable markerless 6 DOF video based handtracking devices became available. These devices simultaneously track the positions and orientations of both user hands in different postures with at least 25 frames per second. Such hand-tracking allows for using the human hands as natural input devices. However, the absence of physical buttons for performing click actions and state changes poses severe challenges in designing an efficient and easy to use 3D interface on top of such a device. In particular, for coupling and decoupling a virtual object’s movements to the user’s hand (i.e. grabbing and releasing) a solution has to be found. In this paper, we introduce a novel technique for efficient two-handed grabbing and releasing objects and intuitively manipulating them in the virtual space. This technique is integrated in a novel 3D interface for virtual manipulations. A user experiment shows the superior applicability of this new technique. Last but not least, we describe how this technique can be exploited in practice to improve interaction by integrating it with RTT DeltaGen, a professional CAD/CAS visualization and editing tool.

Exact Solutions to the Symmetric and Asymmetric Vehicle Routing Problem with Simultaneous Delivery and Pick-Up

In reverse logistics networks, products (e.g., bottles or containers) have to be transported from a depot to customer locations and, after use, from customer locations back to the depot. In order to operate economically beneficial, companies prefer a simultaneous delivery and pick-up service. The resulting Vehicle Routing Problem with Simultaneous Delivery and Pick-up (VRPSDP) is an operational problem, which has to be solved daily by many companies. We present two mixed-integer linear model formulations for the VRPSDP, namely a vehicle-flow and a commodity-flow model. In order to strengthen the models, domain-reducing preprocessing techniques, and effective cutting planes are outlined. Symmetric benchmark instances known from the literature as well as new asymmetric instances derived from real-world problems are solved to optimality using CPLEX 12.1.

Functional regulatory spaces

This article develops the concept of “Functional Regulatory Space” (FRS) in order to analyze the new forms of State action addressing (super) wicked problems. A FRS simultaneously spans several policy sectors, institutional territories and levels of government. It suggests integrating previous policy theories that focused on “boundary-spanning regime,” “territorial institutionalism” or multi-level governance. The FRS concept is envisaged as a Weberian “ideal-type” of State action and is applied to the empirical study of two European cases of potential FRS: the integrated management of water basins and the regulation of the European sky through functional airspace blocks. It will be concluded that the current airspace regulation does match the ideal-type of FRS any better than the water resource regulation does. The next research step consists in analyzing the genesis and institutionalization of potential FRS addressing other (super) wicked problems such as climate change and economic, security, health and immigration issues in different institutional contexts as well as at various levels of governance.

Dimension Distortion by Sobolev Mappings in Foliated Metric Spaces

We quantify the extent to which a supercritical Sobolev mapping can increase the dimension of subsets of its domain, in the setting of metric measure spaces supporting a Poincaré inequality. We show that the set of mappings that distort the dimensions of sets by the maximum possible amount is a prevalent subset of the relevant function space. For foliations of a metric space X defined by a David–Semmes regular mapping Π : X → W, we quantitatively estimate, in terms of Hausdorff dimension in W, the size of the set of leaves of the foliation that are mapped onto sets of higher dimension. We discuss key examples of such foliations, including foliations of the Heisenberg group by left and right cosets of horizontal subgroups.