Examination of the physical processes associated with the keyhole region of variable polarity plasma arc welds in aluminum alloy 2219

The morphology and properties of the Variable Polarity Plasma Arc (VPPA) weld composite zone are intimately related to the physical processes associated with the keyhole. This study examined the effects of oxide, halide, and sulfate additions to the weld plate on the keyhole and the weld pool. Changes in both the arc plasma character and the bead morphology were correlated to the chemical environment of the weld. Pool behavior was observed by adding flow markers to actual VPPA welds. A low temperature analog to the welding process was developed. The results of the study indicate that oxygen, even at low partial pressures, can disrupt the stable keyhole and weld pool. The results also indicate that the Marangoni surface tension driven flows dominate the weld pool over the range of welding currents studied

Characterization of the corrosion resistance of several alloys to dilute biologically active solutions

Sulfate reducing bacteria and acid producing bacteria/fungi detected in hygiene waters increased the corrosion rate in aluminum alloy. Biologically active media enhanced the formation of pits on metal coupons. Direct observation of gas evolved at the corrosion sample, coupled with scanning electron microscopy (SEM) and energy dispersive x-ray analysis of the corrosion products indicates that the corrosion rate is increased because the presence of bacteria favor the reduction of hydrogen as the cathodic reaction through the reaction of oxygen and water. SEM verifies the presence of microbes in a biofilm on the surface of corroding samples. The bacterial consortia are associated with anodic sites on the metal surface, aggressive pitting occurs adjacent to biofilms. Many pits are associated with triple points and inclusions in the aluminum alloy microstructure. Similar bacterial colonization was found on the stainless steel samples. Fourier transform Infrared Spectroscopy confirmed the presence of carbonyl groups in pitted areas of samples exposed to biologically active waters

Characterization of the corrosion resistance of biologically active solutions: The effects of anodizing and welding

An understanding of fabrication processes, metallurgy, electrochemistry, and microbiology is crucial to the resolution of microbiologically influenced corrosion (MIC) problems. The object of this effort was to use AC impedance spectroscopy to characterize the corrosion resistance of Type II anodized aluminum alloy 2219-T87 in sterile and biologically active media and to examine the corrosion resistance of 316L, alloy 2219-T87, and titanium alloy 6-4 in the welded and unwelded conditions. The latter materials were immersed in sterile and biologically active media and corrosion currents were measured using the polarization resistance (DC) technique

The keyhole region in VPPA welds

The morphology and properties of the Variable Polarity Plasma Arc (VPPA) weld composite zone are intimately related to the physical processes associated with the keyhole. The effects of microsegregation and transient weld stress on macrosegregation in the weld tool are examined. In addition the electrical character of straight and reverse polarity portions of the arc cycle were characterized. The results of the former study indicate that alloy 2219 is weldable because large liquid volumes are available during latter stages of weld solidification. Strains in the pool region, acting in conjunction with weld microsegregation can produce macrosegregation great enough to produce radiographic contrast effects in welds. Mechanisms of surface copper enrichment were identified. The latter study has demonstrated that increased heat is delivered to workpieces if the reverse polarity proportion of the weld cycle is increased. Current in the straight polarity portion of the welding cycle increased as the reverse cycle proportion increased. Voltage during reverse polarity segments is large

Fully sustainable energy module - Stage 1: Source research and development

The rising cost of energy, particularly in the form of electrical power is a concern for business and households predominately in rural regions of Western Australia. The higher ongoing costs due to aging assets and infrastructure make it a genuine expense that almost always has the customer looking for cheaper options. Two particular businesses commissioned a project for developing a renewable approach to help satisfy their demands which due to the size and nature of the operation required a medium scale system that was both economical and environmentally sustainable. The project purpose was to research and build the first stage or the “source” of a small prototype to address these concerns in the form of a Fully Sustainable Energy Module (FSEM). The objective is to compete or better the average cost per kilowatt hour of the Western Australian electricity suppliers, Horizon Power (HP) and those making up the South West Interconnected System (SWIS). While assessing the design options of the FSEM, various types of software were used extensively to assist in clarifying the optimum designs throughout the project for an initial theoretical approach. Designs such as a custom Parabolic/hyperbolic reflector and Fresnel lens directed to a Concentrator Solar Cell Receiver Assembly (CSCRA), coolant pumping for junction temperature control and simulation of multiple system configurations for electrical power requirements were assessed to maximise energy output per square metre of solar output. Building a prototype requires a sound knowledge base to ensure that it gives the output expected. Data that can assist inform decisions made to further enhance its operation giving the best possible design for final production. Developing an understanding of a feasibility study on the proof of concept for prototype building is further enhanced by researching the importance and structure of project plans and business expectations. It highlights that the strengths and weakness that need considering and help to show a route to a successful finished product. Prevalent was the design issue for the parabolic/hyperbolic reflector and the intricacies that exposed the difficulty in getting the system to work efficiently due to very small tolerances in construction. When finally settling with a Fresnel lens type the “source” of the FSEM prototype at the time of publication showed practical results of DC output of cell capacity and consistent hot water set at various temperatures showing solar energy transferred

Fr. Daniel Walsh, C.S.Sp.

Fr. Daniel Walsh, C.S.Sp. [b. 1958] was ordained in 1991. He attended Duquesne University, the University of St. Thomas, and Catholic Theological Union, where he earned a Master of Divinity in 1991. From 1992-96, he was a missionary in Carauari, Amazonas, Brazil, going on to serve in many different roles at universities and dioceses across the United States, including as the University Chaplain and Director for Campus Ministry at Duquesne University from 2013-18. Fr. Walsh is a Parochial Vicar for St. Paul Cathedral Parish in the Catholic Diocese of Pittsburgh. This is interview 3 of 4.https://dsc.duq.edu/sohp/1004/thumbnail.jp

Growth in Public Interest and Scientific Research on Kinesiology Taping

Kinesiology taping has grown in popularity, though there are a number of unsubstantiated claims made by some kinesiology taping advocates. An investigation was conducted into trends in general and scientific interest in kinesiology taping. Data in the public domain (Google Trends and Google Scholar data) indicated significant growth of interest both in terms of public search queries and scientific publications relevant to kinesiology taping. Cyclical trends in interest relevant to kinesiology taping were identified. Segmented regression indicated some of the growth in interest in kinesiology taping may be attributed to exposure of spectators of the Olympic Games to kinesiology taping in athletes. Despite substantial growth in research on kinesiology taping there remain unsubstantiated claims

Gift Tax Returns as a Planning Strategy

Timely filing of a properly prepared gift tax return will begin the statute of limitations period for revaluing the gift for gift tax purposes, but not necessarily for estate tax purposes. Walsh describes how the Taxpayer Relief Act of 1997 (TRA\u2797) can provide a taxpayer with potential solutions and describes how the final regulations provide planning opportunities for attorneys to assist their clients

Neutral Isn’t Neutral: An Analysis of Misinformation and Sentiment in the Wake of the Capitol Riots

January 6th, 2021 was a significant moment in the history of the United States of America. Protestors stormed the Capitol building over the results of the 2020 presidential election in which Joseph R. Biden defeated incumbent president Donald J. Trump. The Capitol riots were partially incited by the presence of misinformation on social media and was an example of the power misinformation has. This study presented two questions. Question one pertains to the sentiment analysis of verified Twitter users and their sentiment towards Trump. Question two pertains to analyzing tweets from verified accounts for misinformation between the dates of January 6th, 2021 and January 13th, 2021. To answer these questions, a machine learning sentiment analysis was conducted on 13 randomly selected Twitter accounts with noted liberal and conservative political leanings to assess their sentiment towards Trump. The accounts were analyzed and then categorized as being either anti-Trump or Trump-neutral. Once the accounts were appropriately categorized a collection of their tweets mentioning Trump were documented to create a consecutive day sample to examine their reporting and analyze how misinformation differed between the two. The results of this study show that one, sentiment analysis is a useful tool for examining and categorizing tweets and their overall accounts based on their sentiments and two, that there was a notable difference in the spread of misinformation between the two categories