A Study of Melt Ratio and Microstructure in Dissimilar Fusion Welds

We studied the microstructure in the Ti/Ni laser welds using optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). The welds are asymmetric with respect to the initial butt joint. Despite its higher melting point, Ti melts more than Ni due to its lower thermal conductivity, but because of the high density of Ni the average composition of the weld is Ti–50at%Ni. Composition changes very steeply near the fusion interfaces in both Ti and Ni with associated microstructural changes. The variation is of much lesser magnitude in the rest of the weld, reflecting a well-mixed melt pool on a macroscopic scale. Growth of base metal grains into the weld pool at the fusion interfaces were found to be severely restricted at both Ti and Ni ends. The Ti fusion interface is marked by a band consisting of Ti2Ni dendrites which grow toward the Ti base metal and stopped base metal grains into weld pool. Layers of intermetallic phases (Ni3Ti, Ni3Ti+TiNi, TiNi) form at the Ni fusion interface. TiNi and Ti2Ni are the major phases that appear in the bulk of the weld. From XRD results show that solid state transformation of TiNi leads to the formation of the R-phase and martensite, which reflect the composition heterogeneity in the weld. Non-equilibrium phase Ni2Ti was also observed in the weld

Metallurgical Characterization of Penetration Shape Change in Workpiece Vibration-Assisted Tandem-Pulsed Gas Metal Arc Welding

Tandem-pulsed gas metal arc welding (TP-GMAW) simultaneously uses two wire-electrodes to enhance the material deposition rate, leading to the generation of a finger-shaped penetration as one of the arcs penetrates deeper than the other. On the other hand, workpiece vibration is one of the techniques used to control the microstructure of weld metal and a heat-affected zone. It is incidentally found that a specific vibration condition changes the finger-shaped penetration into pan-bottom shaped penetration in the TP-GMAWeven though the vibration energy is much lower than the arc energy. Microstructure observation and elemental analysis are carried out for the welds fabricated without vibration and with three kinds of vibration modes, namely sine, random, and shock. The specific sine-mode vibration exhibits pan-bottom. The other modes of vibration in the same welding conditions exhibited invariable finger-shaped penetration. The Si atoms as a tracer distribute uniformly in the sine-mode. However, Si atoms segregate at the bottom of the finger-shaped weld metal with the random-mode and shock-mode workpiece vibrations. The weld pool shape change is prominent at a specific frequency. A resonance phenomenon between the droplet flow pattern and the molten material flow in the weld pool is likely to play a vital role in the change. © 2020 by the authors

Python game design for children: Games and programming resources

This project is focused on helping middle and high school students learn how to program and think computationally. We are creating a set of resources that will be used by the students to understand programming, Python, and PyGames concepts. These resources will be used for teaching the two one-week summer camps through Clemson University\u27s Pre-Collegiate programs in June and July 2014. This camp has been offered at Georgia Tech and Clemson University for two summers using a drag and drop visual programming language to help students create games. The instructors have found that the camp attendees do not find the visual programming language to be challenging enough. Thus, we are designing curricula to teach introductory computing concepts with the Python and PyGames programming languages in a fun and creative way and to give students the opportunity to learn to design and program their own games. We are also designing and creating our own games as a way to learn the language and have examples for the kids in the camp to build upon. This project was initiated this semester and we will pilot resources this summer during the two weeks of camp. We will showcase the initial games and resources created for this project

First Isolation of West Nile virus from a Patient with Encephalitis in the United States

West Nile virus (WNV) was isolated from a patient who developed encephalitis while undergoing treatment with CHOP (cyclophosphamide, hydroxydoxorubicin, vincristine [Oncovin], predisone) and rituximab for a non-Hodgkin B-cell lymphoma. Both standard reverse transcription–polymerase chain reaction (RT-PCR) and Taqman RT-PCR established the diagnosis of WNV infection from cerebrospinal fluid (CSF). Several whole blood samples and one serum sample underwent further testing. CSF and serum samples were negative for WNV antibody; however, all samples were positive by both RT-PCR assays. Infectious virus was recovered from a blood sample, and its identity was confirmed by using a WNV-specific immunofluorescence assay. The complete WNV genomes determined from CSF and from the virus isolate adapted from cell culture were the same. The results represent the first complete WNV genome sequence obtained directly from human CSF and the first time that infectious WNV has been recovered from a patient with encephalitis in North America

Determination of the orthotropic material properties of a fiber-reinforced composite laminate

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references.Not availabl

Triage Status is a Predictor of Higher Emergency Department Utilization Among Traumatically Injured Patients with Sickle Cell Disease

Introduction: Sickle cell disease (SCD) impacts one in 500 African Americans and is associated with vaso-occlusive events (VOE), leading to severe complications if unmanaged. Effective pain management in emergency settings is often delayed due to stigma and limited resources. Given similar inflammatory responses characterizing both VOE and traumatic injury, this study is the first to examine whether traumatic injury aggravates VOE-related outcomes and pain management needs. Methods: A retrospective chart review was conducted from an SCD clinic in Western Pennsylvania from 2000-2021. SCD and injury status was determined using ICD-9/10 data. Patients were sorted into three treatment groups based on injury hospital management: 1) neither trauma triage nor ICU admission (“early discharge”), 2) triage but no ICU (“triage only”), and 3) “triage-ICU”. Primary outcomes included pre/post-injury annual frequency of VOE events and ED length of stay (LOS) for VOE; secondary outcomes included time from injury to first VOE. Results: A total of 356 patients with SCD from 2000-2021 were identified; 55 patients with prior traumatic injury were included. No significant increase in annual frequency of VOE or ED LOS for VOE post-injury. Triage only individuals experienced a significant increase in ED LOS for first VOE (MD= 61.3 hours, p=0.038). All triaged-injured SCD patients experienced a significant post-injury increase in LOS for VOE (MD=34.06 hours, t=2.205, p=0.023), compared to non- triaged (MD = 0.01, t=2.006, p=0.997). Kaplan-Meier log-rank test revealed early discharge individuals experienced a VOE event within 2.93 days of injury, followed by triage-ICU individuals at 52.375 days and triage-only individuals at 100.16 days (p=0.0058). No-ICU patients experienced a VOE event in less than 1 day, compared to those ICU patients at 52.16 days (K2 log rank = 0.9, p=0.33). Hazard rate of VOE events was affected by trauma triage (p=0.06). Conclusions: Triage status was a significant predictor in poor VOE outcomes, resulting in increased annual VOE events and longer ED length of stay for VOE. It is in the best interest of public health experts and of public health significance to develop specific triage protocols for ED management of the injury in SCD patients

Advances in Lipid Extraction Methods—A Review

Extraction of lipids from biological tissues is a crucial step in lipid analysis. The selection of appropriate solvent is the most critical factor in the efficient extraction of lipids. A mixture of polar (to disrupt the protein-lipid complexes) and nonpolar (to dissolve the neutral lipids) solvents are precisely selected to extract lipids efficiently. In addition, the disintegration of complex and rigid cell-wall of plants, fungi, and microalgal cells by various mechanical, chemical, and enzymatic treatments facilitate the solvent penetration and extraction of lipids. This review discusses the chloroform/methanol-based classical lipid extraction methods and modern modifications of these methods in terms of using healthy and environmentally safe solvents and rapid single-step extraction. At the same time, some adaptations were made to recover the specific lipids. In addition, the high throughput lipid extraction methodologies used for liquid chromatography-mass spectrometry (LC-MS)-based plant and animal lipidomics were discussed. The advantages and disadvantages of various pretreatments and extraction methods were also illustrated. Moreover, the emerging green solvents-based lipid extraction method, including supercritical CO2 extraction (SCE), is also discussed