3,232 research outputs found

    Vibration Bending Fatigue Analysis of Additively Repaired Ti-6Al-4V Airfoil Blades

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    Repairing airfoil blades is necessary to extend the life of turbine engines. Directed energy deposition (DED) additive manufacturing (AM) provides the ability to add material at a specific location on an existing component. In this work, AM repairs on Ti-6Al-4V airfoil blades were analyzed to determine what effect the repair will have on the blade performance in high cycle vibration fatigue testing. Targeted sections were cut out of airfoil blades near high stress locations and repaired using DED. To understand the defects that arose with this type of repair, computed tomography imaging was used to quantify the defects from the AM process. The blades were then tested until failure using vibration bending fatigue to simulate turbine engine loading conditions. Results suggest that understanding the impact of internal and surface level defects arising from the AM process is critical towards the implementation of AM repair in aerospace components under fatigue loading

    Supersonic Propulsion: Inlet Shock Wave/Boundary Layer Interaction in a Diffuser

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    Using a finite-volume approach and ANSYS/FLUENT, supersonic flow over a 2-D ramp of varying angles is modeled. The computational results from this model will be used to further explore the design of supersonic diffusers used on military aircraft. Using grid capturing features and inflation layers, shockwave and boundary layer interactions will be observed as well as wave-associated pressure changes in supersonic turbulent flow. The Spalart-Allmaras single-equation model of turbulent flow will be used in all simulations to more accurately represent the phenomena that occur in such high-speed environments. The size of upstream zones and recirculation zones will be obtained through this model where applicable. Downstream zones of influence will be represented in terms of skin friction coefficient. Single-ramp data will be compared with double-ramp data to better understand how diffusers are modeled in industry for supersonic aircraft. This data will be the basis for the latter simulations representing internal compression and spike inlets. Inlet geometries are compared based on their stagnation pressure losses

    Podcast PD

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    Reports of police corruption are becoming more and more common in American media. In this podcast, we will discuss the distrust between the police and the community, some of the causes of the problem, and will address ways to resolve it. Throughout the duration of the podcast, we will provide the viewpoint of both sides and try to explain why they feel the way they do. To get the community’s input, our group decided to poll random students across campus to get a better understanding on their view of the police state in the US. For the police’s side, we decided to interview an officer for his input on why these controversial stories are being displayed all over the media, and asked what he thinks should be done to improve the relationship between the two parties. By including the thoughts of the opposing sides, as well as using data from some of the instances reported in the media, we hope that our listeners will gain a better understanding of the issue and proactively try to improve the relationship between the community and the police

    Cancer: An Organismic Approach

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    Plump it Up: Malnutrition in Guatemala

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    https://digitalcommons.wpi.edu/gps-posters/1474/thumbnail.jp

    Relationship Among Emotional Intelligence and/or Extrovert Bias on Perceived Stress Levels in DPT Students

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    Purpose/Hypothesis: Students in graduate level DPT programs function at varying levels. Some students thrive and others struggle to maintain required minimum levels of academic performance. When considering admission of applicants, and when assisting enrolled students, consideration of factors contributing to academic success is of interest. Stress has been shown to be prevalent in a wide range of students and has many negative effects including poor life satisfaction, increased clinical burnout, and reduced academic performance. Research has shown a correlation between higher emotional intelligence (EI) and decreased stress levels in medical, nursing, and undergraduate students. The purpose of this study was to examine if emotional intelligence (EI) and/or extrovert bias correlates with perceived stress levels in Doctor of Physical Therapy (DPT) students. It was hypothesized that students with higher emotional intelligence and more extroverted personalities would experience lower levels of perceived stress. Participants: After providing consent, a convenience sample of 60 first and second year DPT students (33 female) with age range 23 to 38 participated in the current study. Participation was voluntary and 60 of a possible 72 students chose to participate. Materials/Methods: After obtaining informed consent, participants completed Goldberg’s IPIP-Neo questionnaire (extraversion), Perceived Stress Scale (PSS) and Assessing Emotions Scale (emotional intelligence). Each of these tools have demonstrated validity and reliability for the respective areas measured. Surveys were administered to students and results were analyzed for possible relationships between extraversion and stress levels as well as EI and stress levels using a Spearman Correlation test. Results: Spearman Correlation analyses were conducted with a significant negative correlation between EI and perceived stress rs = -0.291, p= 0.026 and a non-significant negative correlation between extraversion and perceived stress rs = -1.36, p= 0.305. Discussion: In the current sample, EI had a significant negative relationship with perceived stress levels, with higher EI scores correlating to lower levels of stress. The relationship between extraversion and perceived stress was non-significant. Clinical Relevance: Doctorate level graduate programs can be considered intense and very stressful. Admission of qualified students equipped to meet the demands of a DPT program has great importance. Establishing a correlation between EI, introversion/extraversion bias, and stress may help DPT programs further assess prospective students. Consideration of factors correlated with higher perceived stress may be useful when providing resources to admitted students to facilitate academic success

    Measuring the Numerical Viscosity in Simulations of Protoplanetary Disks in Cartesian Grids -- The Viscously Spreading Ring Revisited

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    Hydrodynamical simulations solve the governing equations on a discrete grid of space and time. This discretization causes numerical diffusion similar to a physical viscous diffusion, whose magnitude is often unknown or poorly constrained. With the current trend of simulating accretion disks with no or very low prescribed physical viscosity, it becomes essential to understand and quantify this inherent numerical diffusion, in the form of a numerical viscosity. We study the behavior of the viscous spreading ring and the spiral instability that develops in it. We then use this setup to quantify the numerical viscosity in Cartesian grids and study its properties. We simulate the viscous spreading ring and the related instability on a two-dimensional polar grid using PLUTO as well as FARGO, and ensure convergence of our results with a resolution study. We then repeat our models on a Cartesian grid and measure the numerical viscosity by comparing results to the known analytical solution, using PLUTO and Athena++. We find that the numerical viscosity in a Cartesian grid scales with resolution as approximately νnumΔx2\nu_{num}\propto\Delta x^2 and is equivalent to an effective α104\alpha\sim10^{-4} for a common numerical setup. We also show that the spiral instability manifests as a single leading spiral throughout the whole domain on polar grids. This is contrary to previous results and indicates that sufficient resolution is necessary in order to correctly resolve the instability. Our results are relevant in the context of models where the origin should be included in the computational domain, or when polar grids cannot be used. Examples of such cases include models of disk accretion onto a central binary and inherently Cartesian codes

    ICT Security Tools and Techniques Among Higher Education Institutions: A Critical Review

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    Higher education institutions (HEIs) are increasingly relying on digital technologies for classroom and organizational management, but this puts them at higher risk for information and communication (ICT security attacks. Recent studies show that HEIs have experienced more security breaches in ICT security composed of both cybersecurity an information security. A literature review was conducted to identify common ICT security practices in HEIs over the last decade. 11 journal articles were profiled and analyzed, revealing threats to HEIs’ security and protective measures in terms of organizational security, technological security, physical security, and standards and frameworks. Security tools and techniques were grouped into categories with specific ways to protect ICT security. HEIs also implement general security standards and guidelines, such as the ISO 27000-series and Center for Internet Security (CIS) controls, in their framework. Through synthesis and analysis of ICT security tools and techniques among HEIs, this critical review hopes to provide research directions on IT governance that academic and technical administrators can further explore to secure their information resources
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