144 research outputs found

    Exploring the Kinetic and Thermodynamic Relationship of Charge Transfer Reactions Used in Localized Electrodeposition and Patterning in a Scanning Bipolar Cell

    Get PDF
    Bipolar electrochemistry involves spatial separation of charge balanced reduction and oxidation reactions on an electrically floating electrode, a result of intricate coupling of the work piece with the ohmic drop in the electrochemical cell and to the thermodynamics and kinetics of the respective bipolar reactions. When paired with a rastering microjet electrode, in a scanning bipolar cell (SBC), local electrodeposition and patterning of metals beneath the microjet can be realized without direct electrical connections to the workpiece. Here, we expand on prior research detailing electrolyte design guidelines for electrodeposition and patterning with the SBC, focusing on the relationship between kinetics and thermodynamics of the respective bipolar reactions. The kinetic reversibility or irreversibility of the desired deposition reaction influences the range of possible effective bipolar counter reactions. For kinetically irreversible deposition systems (i.e., nickel), a wider thermodynamic window is available for selection of the counter reaction. For kinetically reversible systems (i.e., copper or silver) that can be easily etched, tight thermodynamic windows with a small downhill driving force for spontaneous reduction are required to prevent metal patterns from electrochemical dissolution. Furthermore, additives used for the bipolar counter reaction can influence not only the kinetics of deposition, but also the morphology and microstructure of the deposit. Cyclic voltammetry measurements help elucidate secondary parasitic reduction reactions occurring during bipolar nickel deposition and describe the thermodynamic relationship of both irreversible and reversible bipolar couples. Finally, finite element method simulations explore the influence of bipolar electrode area on current efficiency and connect experimental observations of pattern etching to thermodynamic and kinetic relationships

    Security and privacy challenges in smart cities

    Get PDF
    © 2018 Elsevier Ltd The construction of smart cities will bring about a higher quality of life to the masses through digital interconnectivity, leading to increased efficiency and accessibility in cities. Smart cities must ensure individual privacy and security in order to ensure that its citizens will participate. If citizens are reluctant to participate, the core advantages of a smart city will dissolve. This article will identify and offer possible solutions to five smart city challenges, in hopes of anticipating destabilizing and costly disruptions. The challenges include privacy preservation with high dimensional data, securing a network with a large attack surface, establishing trustworthy data sharing practices, properly utilizing artificial intelligence, and mitigating failures cascading through the smart network. Finally, further research directions are provided to encourage further exploration of smart city challenges before their construction

    Building a Standard Measurement Platform

    Get PDF
    Network management is achieved through a large number of disparate solutions for different technologies and parts of the end-to-end network. Gaining an overall view, and especially predicting the impact on a service user, is difficult. Recently, a number of proprietary platforms have emerged to conduct end-to-end testing from user premises; however, these are limited in scale, interoperability, and the ability to compare like-for-like results. In this article we show that these platforms share similar architectures and can benefit from the standardization of key interfaces, test definitions, information model, and protocols. We take the SamKnows platform as a use case and propose an evolution from its current proprietary protocols to standardized protocols and tests. In particular, we propose to use extensions of the IETF's IPFIX and NETCONF/YANG in the platform. Standardization will allow measurement capabilities to be included on many more network elements and user devices, providing a much more comprehensive view of user experience and enabling problems and performance bottlenecks to be identified and addressed.Publicad

    The Roles of Extrinsic and Intrinsic Factors in the Freshwater Life-History Dynamics of a Migratory Salmonid

    Get PDF
    Key life-cycle transitions, such as metamorphosis or migration, can be altered by a variety of external factors, such as climate variation, strong species interactions, and management intervention, or modulated by density dependence. Given that these life-history transitions can influence population dynamics, understanding the simultaneous effects of intrinsic and extrinsic controls on life-history expression is particularly relevant for species of management or conservation importance. Here, we examined how life histories of steelhead (Oncorhynchus mykiss) are affected by weather, pink salmon abundance (Oncorhynchus gorbuscha), experimental nutrient addition, and density-dependent processes. We tested for impacts on the size of steelhead smolts (juveniles migrating to the sea), as well as their age and abundance across four decades in the Keogh River, British Columbia, Canada. Larger steelhead smolts were associated with warmer years and artificial nutrient addition. In addition, higher pink salmon abundance and artificial nutrient addition correlated with juvenile steelhead migrating at younger ages. While density dependence appeared to be the primary factor regulating the abundance of steelhead smolts, nutrient addition and temperature were positively and negatively associated with smolt production, respectively, prior to 1991, and pink salmon spawning abundance was positively associated with smolt production after 1990. Thus, this study provides evidence that the temporal dynamics of one species of salmon is linked to the juvenile life history of co-occurring steelhead. A complex interplay of species interactions, nutrient subsidies, density dependence, and climatic variation can control the life-history expression of species with complex life cycles

    Construing the cultural other and the self: A Personal Construct analysis of English and Italian perceptions of national character

    Get PDF
    How we perceive other cultures is arguably of increasing importance in contemporary society, impacting on realms such as international relations, business and tourism. The qualitative research reported in this paper was carried out in the UK and in Italy and adopted a Personal Construct Psychology approach. It aimed to explore intercultural perceptions in a sample of people who had some degree of experience with the ‘other’ culture, and a unique feature of the research is that it asked how those perceptions might be affected if people from both cultures are given access to each other’s perceptions. There was considerable commonality in the perceptions of the English and Italian participants, and each culture envied some of the qualities of the other. However, they initially struggled to accommodate how they were seen by the other and endeavoured to resolve difference by construing at a more superordinate level. The findings also suggest that national identity is rooted in the construing of others’ constructions, achieved through relationship and comparison

    Cellular plasticity in response to suppression of storage proteins in the Brassica napus embryo

    Get PDF
    The tradeoff between protein and oil storage in oilseed crops has been tested here in oilseed rape (Brassica napus) by analyzing the effect of suppressing key genes encoding protein storage products (napin and cruciferin). The phenotypic outcomes were assessed using NMR and mass spectrometry imaging, microscopy, transcriptomics, proteomics, metabolomics, lipidomics, immunological assays, and flux balance analysis. Surprisingly, the profile of storage products was only moderately changed in RNA interference transgenics. However, embryonic cells had undergone remarkable architectural rearrangements. The suppression of storage proteins led to the elaboration of membrane stacks enriched with oleosin (sixfold higher protein abundance) and novel endoplasmic reticulum morphology. Protein rebalancing and amino acid metabolism were focal points of the metabolic adjustments to maintain embryonic carbon/nitrogen homeostasis. Flux balance analysis indicated a rather minor additional demand for cofactors (ATP and NADPH). Thus, cellular plasticity in seeds protects against perturbations to its storage capabilities and, hence, contributes materially to homeostasis. This study provides mechanistic insights into the intriguing link between lipid and protein storage, which have implications for biotechnological strategies directed at improving oilseed crops

    Perdeuteration of cholesterol for neutron scattering applications using recombinant Pichia pastoris

    Get PDF
    Deuteration of biomolecules has a great impact on both quality and scope of neutron scattering experiments. Cholesterol is a major component of mammalian cells, where it plays a critical role in membrane permeability, rigidity and dynamics, and contributes to specific membrane structures such as lipid rafts. Cholesterol is the main cargo in low and high-density lipoprotein complexes (i.e. LDL, HDL) and is directly implicated in several pathogenic conditions such as coronary artery disease which leads to 17 million deaths annually. Neutron scattering studies on membranes or lipid-protein complexes exploiting contrast variation have been limited by the lack of availability of fully deuterated biomolecules and especially perdeuterated cholesterol. The availability of perdeuterated cholesterol provides a unique way of probing the structural and dynamical properties of the lipoprotein complexes that underly many of these disease conditions. Here we describe a procedure for in vivo production of perdeuterated recombinant cholesterol in lipid-engineered Pichia pastoris. Using flask and fed-batch fermenter cultures in deuterated minimal medium perdeuteration of the purified cholesterol was verified by mass spectrometry and its use in a neutron scattering study was demonstrated using neutron reflectometry

    Campus Compact: Rain garden

    Get PDF
    Our undergraduate research project is the planning, development, and installation of a phytoremediating rain garden on the SNHU campus. As part of an EPA grant-funded program, our group will be responsible for the entire creation process of this rain garden, from preplanning, budgeting, and research, to installation and policy and procedure development. This project aims to accomplish multiple goals, namely, 1) to identify and remediate soil and water pollutants in the specified portion of the SNHU campus, 2) to increase campus awareness of environmental issues and actions that can be taken to help, and 3) to hopefully serve as proof of concept for the future installation of further rain gardens at SNHU. The site will be highly visible, and all relevant documentation will be created and catalogued by our group. (Author abstract)Allen, C., Braun, J., Corcoran, M., Demetriou, A., De Redon, T., Fournier, S.,...Young, B. (2014). SNHU rain garden. Retrieved from http://academicarchive.snhu.ed
    • 

    corecore