108 research outputs found
High Performance of MWCNTs - Chitosan Modified Glassy Carbon Electrode for Voltammetric Trace Analysis of Cd(II)
No full textGlassy carbon electrode was nanostructured and assembled with a scaffold of multiwalled carbon nanotubes and chitosan biopolymer for Cadmiun (II) ion detection in aqueous solutions. Using cyclic voltammetry (CV) and electrochemical impedance spectroscopy, the arrangement was characterized. The optimization of different parameters for the electrochemical detection ion Cadmiun ions were properly done using square wave voltammetry (SWV). A buffer of acetates and pH of 5 was used. Results showed a limit of detection of 0.09 μg L-1. Selectivity in detection was demonstrated was ensured using SWV as well with this modified electrode for Cd(II) detection in presence of another toxic heavy metal ions: Pb(II), Co(II) 30 μg L-1 and Hg(II) 100 μg L-1. This arrangement coupled with square wave voltammetry constitutes a different perspective for further investigations in the simultaneous detection of this species as well in a very low limit of detection
Electrochemical behavior of Zn‐REP nanohybrid coatings during marine Shewanella sp. biofilm formation
No full textNanohybrid coatings, particularly zinc‐rich epoxy coatings, can protect steel
from the harsh marine environment through a physical barrier mechanism
and a cathodic protective effect based on anodic electrochemical reactions
involving zinc particles in the coating. New additives, such as carbon nanotubes
(CNTs), produce more efficient multifunctional coatings by enhancing
both protective mechanisms. In this study, the electrochemical behavior and
corrosion mechanisms of zinc‐rich epoxy nanohybrid coatings with the addition
of CNTs were investigated in the presence of a Shewanella sp. marine
strain to evaluate their influence on biofilm formation by this Gram‐negative
bacterium. The electrochemical activity was monitored over time with opencircuit
potential, electrochemical impedance spectroscopy, and scanning
electron microscopy coupled with energy‐dispersive X‐ray spectroscopy.
A mixed mechanism was observed starting from early exposure. When the
content of CNTs was doubled, the biofilm adherence improved, thus
suggesting a favorable effect of CNTs on biofilm formation, attributable to
increased production of bacterial exopolymeric substances facilitating biofilm
development. The electrochemical impedance spectroscopy results suggested a
correlation with biofilm formation as a second barrier layer with the lowest
impedance magnitude in coatings with different multiwalled CNT content
Formation of Escherichia coli biofilms on the titanium alloy Ti6Al4V: analysis of the interface and assessment of corrosion
No full textBacterial biofilm that formed when the Ti6Al4 V alloy was exposed to Escherichia coli, was monitored
over 48 h by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) to
estimate the rate of corrosion and the influence of the bacteria on this process. High-resolution
scanning electron microscopy was used to examine bacterial growth, colonisation and the process
of biofilm formation. Our results highlighted several critical points regarding the impact of E. coli
and its use as a model for monitoring biofilm formation and the biocorrosion of this alloy.
Impedance spectra revealed the formation of a compact passive film after 48-hour exposure to an
aging culture of E. coli in chloride media. The formation of the biofilm influenced the resistance to
corrosion. Biofilm impedance parameters that emerged over time corresponded directly to the
properties of a typical exponential bacterial growth curve determined by ultraviolet-visible light
spectroscopy
Life after sexual trauma and incarceration: a restorative model for wholeness for women who suffered sexual violence
No full textThe abuse of a woman’s body had been a normative practice since the recordings of Old Testament narratives. This study is designed to confront the inherent gender bias that contributed to the devaluation and abuse of a female body, especially for women in minority communities. How did such a transgression become acceptable behavior for men, while women are penalized and even harshly judged for being the victim? Once the pattern of abused has been identified, the research will show sexual traumatization detrimentally impacts the overall behavior of the victim, occasionally leading to criminal activities which further exacerbate mental health issues never properly addressed. Women who are violated suffer mentally and emotionally, yet minimal attention is given to a woman to acknowledge and address the impact of the violation. The research consists of a historical autopsy of sexually traumatized women in the biblical narratives, throughout certain periods of slavery and its aftermath and in society in the 21st century. The goal was to determine if common trends are present for women who endured sexual assault. How did they survive, and did they manage to lead a productive life after trauma? It will also examine the failure of society to support victims, by providing a pathway toward healing and wholeness. The research will show that when the biblical narratives are theologically reexamined, the sacred text provides a strategic plan to help any woman recover from any sexual trauma they endured. It will conclude with a vision life workbook to help women begin the difficult work of moving forward after sexual traumatization
Intergenerational ties in Latinx Protestant congregations: sustaining ethnicity through organizational and affective connections
No full textThis paper examines the persistence of intergenerational ties within Latinx Protestant Congregations (LPCs) and the implications these ties have for the persistence of LPCs as distinctly ethnic institutions. Though studies of generational transitions within ethnic congregations tend to emphasize intergenerational discontinuity, this paper uncovers ways that Latinx Protestants maintain intergenerational ties through LPC involvement, both within and across institutional settings. Rather than focusing on the content of intergenerational transmission, such as cultural practices, ethnic material, or explicit identity labels, this paper is concerned with a more preliminary matter of ethnic identity maintenance—the persistence of channels of transmission across generations. In particular, this paper examines how LPC organizational structures sustain cross-generational links, and how later generation Latinxs express affective ties to earlier generation Latinxs. Taking a religious ecology approach, findings are based on in-depth qualitative research conducted within six LPCs, and an informal survey of eleven additional LPCs, all located in the city of Santa Ana, California, a Latinx majority city. Findings suggest that LPCs are successfully cultivating intergenerational ties among a select group of later generation Latinxs, and that later generation Latinxs who stay connected to LPCs value these ties.https://www.mdpi.com/2077-1444/10/9/504/htmPublished versio
Liturgical biography as liturgical theology: co-constructing theology at Hillsong Church, New York City
No full textIn the field of liturgical theology, there is a common understanding that the prescriptive theological claims of theologians do not often match the descriptive, lived reality of worshippers. Put differently, there is a gap between the “primary” theological activity of worship and the formal “secondary” theology of the academic liturgical theologian. Within this interstice lie the liturgical-theological articulations of “ordinary,” non-specialist worshippers. This project argues that liturgical theology has not focused upon the human subject to a sufficient standard and proposes the method of liturgical biography as a descriptive and analytically rich avenue to construct liturgical theologies. Liturgical biography utilizes longitudinal oral interviews and personal journal entries, supported by ethnographic fieldwork, to describe the lived reality of the “ordinary” primary theologian (the worshipper) engaging in worship and liturgical-theological reflection. In addition to a methodological proposal, this project offers and analyzes the liturgical biographies of two worshippers who attend the New York City campus of Hillsong Church, a global Pentecostal megachurch-turned-denomination.
Chapter One discusses the theoretical underpinning to liturgical biography, incorporating the concept of the rhizome developed by Gilles Deleuze and Félix Guattari. Liturgical biography is needed because worship is too rhizomatically complex for the universalizing and prescriptive claims of liturgical theology. Chapter Two provides a working history and liturgical theology of Hillsong Church rendered from Hillsong’s primary sources (i.e., books, sermons, song lyrics, blogs). Chapters Three and Four examine the personal histories and liturgical-theological claims of these two “primary theologians” who attend Hillsong New York City, whose claims are then placed in conversation with liturgical-theological interlocutors and other allied fields of discourse. These chapters are “co-constructed” insofar as the primary theologians’ voices take the lead, but the researcher employs the thematization and organization of the materials. Their liturgical theologies demonstrate the “gap” between primary and secondary theology, elucidate the rhizomatic complexity of worship, and offer unique contributions to liturgical theology, especially by giving voice to the underrepresented perspectives of Pentecostals and Evangelicals. Chapter Five concludes the project by arguing in favor of liturgical biography as a viable method for liturgical theology and further theorizes its ecumenical import.2021-07-25T00:00:00
Energy Efficient and Compact RF High-Power Amplifiers
No full textThe main objectives of this thesis are to improve the energy efficiency and physical form-factor of high-power amplifiers in base station applications. As such, the focus of this dissertation is placed on the outphasing amplifier concept, which can offer high-efficiency, good linearity and excellent opportunities for system integration. With this mind set, various outphasing concepts have been studied at different levels of abstraction, starting from their fundamental operation, to very detailed efficiency and bandwidth considerations. In order to enable the future package integration of complete RF high-power amplifiers and transmitter lineups, dedicated design techniques for very compact and high-power magnetic components have been developed utilizing low-cost wire bonding techniques. Using these techniques, a very low-loss, high-current RF transformer concept was introduced that allows straight forward power scaling in RF amplifiers. Next, to demonstrate the practical use of these low-loss magnetic components with their related design flow, two very compact high-power class-E branch amplifiers were realized and tested. Expanding on these initial works, one of the key demonstrators of this thesis was a "70W fully packaged-integrated GaN outphasing amplifier", which represents a remarkable combination of high-efficiency, high-output power with a very small form factor. Finally, to facilitate the future integration of advanced switchmode outphasing systems in a single package, the design of high-voltage CMOS drivers was discussed and demonstrated. These devices can provide the essential physical link between the final PA stages with the intelligence of the forgoing TX chain, which is typically implemented in standard low-voltage CMOS technologies.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
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