CH-47D Rotating System Fault Sensing for Condition Based Maintenance

The Department of Defense (DoD) has mandated the use of maintenance practices based on component condition rather than component time in service or age. This new practice is known as Condition Based Maintenance, and it relies on accurate detection and identification of material deficiencies in system components. Rotor system components in rotary-wing aircraft can be difficult to monitor due to the rotational environment experienced by the sensors and the difficulty of signal transmission. Current methods are able to detect the existence of a fault in the rotor system but cannot link the vibrations experienced in the airframe to a specific material defect. This results in inefficient maintenance practices associated with identifying the faulty components for repair or replacement. This research seeks to create a model which will enable the identification of component deficiencies in the rotating system from vibration characteristics experienced in the fuselage, in order to increase maintenance efficiencies leading to cost savings and increased operational readiness for in-service CH-47D aircraft

Three dimensional graphics station for computer integrated manufacturing research

Issued as Final report, Project no. E-25-69

Drawing Trees with Perfect Angular Resolution and Polynomial Area

We study methods for drawing trees with perfect angular resolution, i.e., with angles at each node v equal to 2{\pi}/d(v). We show: 1. Any unordered tree has a crossing-free straight-line drawing with perfect angular resolution and polynomial area. 2. There are ordered trees that require exponential area for any crossing-free straight-line drawing having perfect angular resolution. 3. Any ordered tree has a crossing-free Lombardi-style drawing (where each edge is represented by a circular arc) with perfect angular resolution and polynomial area. Thus, our results explore what is achievable with straight-line drawings and what more is achievable with Lombardi-style drawings, with respect to drawings of trees with perfect angular resolution.Comment: 30 pages, 17 figure

Survival Strategies: Doctoral Students’ Perceptions of Challenges and Coping Methods

The purpose of this collective case study was to use a critical dialectical pluralistic (CDP) philosophical lens to investigate select doctoral students’ perceptions about the challenges that they encountered while in a doctorate program and the coping strategies that they found effective in mitigating these challenges. A major goal of CDP is to empower research participants maximally by giving them the role of participant-researchers. Participants were 10 doctoral students enrolled at a Tier-II university in the United States, who were selected via convenience sampling. Each student participated in a face-to-face interview with a member of the research team—consistent with a CDP approach. A qualitative-dominant crossover mixed analysis was used wherein both quantitative and qualitative analyses were used to analyze the qualitative data, with the qualitative analysis phase being dominant. The qualitative analyses (e.g., constant comparison analysis, classical content analysis) revealed the following five themes: compartmentalization of life, outside support systems, justification for participation in program, emotional status, and structure of program. These themes indicated that although challenges are plentiful, particularly in terms of balancing one’s academic life with other obligations, participants found support and encouragement from family, friends, and other doctoral students to be the most beneficial coping strategy. These findings have important implications for the structuring of doctoral programs

P1‐349: Advancing Clinical And Biomarker Research In Ad: The Lead Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152716/1/alzjjalz201906904.pd

An Observationally Constrained Evaluation of the Oxidative Capacity in the Tropical Western Pacific Troposphere

Hydroxyl radical (OH) is the main daytime oxidant in the troposphere and determines the atmospheric lifetimes of many compounds. We use aircraft measurements of O3, H2O, NO, and other species from the Convective Transport of Active Species in the Tropics (CONTRAST) field campaign, which occurred in the tropical western Pacific (TWP) during January–February 2014, to constrain a photochemical box model and estimate concentrations of OH throughout the troposphere. We find that tropospheric column OH (OHCOL) inferred from CONTRAST observations is 12 to 40% higher than found in chemical transport models (CTMs), including CAM-chem-SD run with 2014 meteorology as well as eight models that participated in POLMIP (2008 meteorology). Part of this discrepancy is due to a clear-sky sampling bias that affects CONTRAST observations; accounting for this bias and also for a small difference in chemical mechanism results in our empirically based value of OHCOL being 0 to 20% larger than found within global models. While these global models simulate observed O3 reasonably well, they underestimate NOx (NO + NO2) by a factor of two, resulting in OHCOL ~30% lower than box model simulations constrained by observed NO. Underestimations by CTMs of observed CH3CHO throughout the troposphere and of HCHO in the upper troposphere further contribute to differences between our constrained estimates of OH and those calculated by CTMs. Finally, our calculations do not support the prior suggestion of the existence of a tropospheric OH minimum in the TWP, because during January–February 2014 observed levels of O3 and NO were considerably larger than previously reported values in the TWP

Cortical Gyrification and Sulcal Spans in Early Stage Alzheimer's Disease

Alzheimer's disease (AD) is characterized by an insidious onset of progressive cerebral atrophy and cognitive decline. Previous research suggests that cortical folding and sulcal width are associated with cognitive function in elderly individuals, and the aim of the present study was to investigate these morphological measures in patients with AD. The sample contained 161 participants, comprising 80 normal controls, 57 patients with very mild AD, and 24 patients with mild AD. From 3D T1-weighted brain scans, automated methods were used to calculate an index of global cortex gyrification and the width of five individual sulci: superior frontal, intra-parietal, superior temporal, central, and Sylvian fissure. We found that global cortex gyrification decreased with increasing severity of AD, and that the width of all individual sulci investigated other than the intra-parietal sulcus was greater in patients with mild AD than in controls. We also found that cognitive functioning, as assessed by Mini-Mental State Examination (MMSE) scores, decreased as global cortex gyrification decreased. MMSE scores also decreased in association with a widening of all individual sulci investigated other than the intra-parietal sulcus. The results suggest that abnormalities of global cortex gyrification and regional sulcal span are characteristic of patients with even very mild AD, and could thus facilitate the early diagnosis of this condition

Exploring the relationship between chronic undernutrition and asymptomatic malaria in Ghanaian children

<p>Abstract</p> <p>Background</p> <p>A moderate association has been found between asymptomatic parasitaemia and undernutrition. However, additional investigation using the gold standard for asymptomatic parasitaemia confirmation, polymerase chain reaction (PCR), is needed to validate this association. Anthropometric measurements and blood samples from children less than five years of age in a rural Ghanaian community were used to determine if an association exists between chronic undernutrition and PCR-confirmed cases of asymptomatic malaria.</p> <p>Methods</p> <p>This was a descriptive cross-sectional study of 214 children less than five years of age from a community near Kumasi, Ghana. Blood samples and anthropometric measurements from these children were collected during physical examinations conducted in January 2007 by partners of the Barekuma Collaborative Community Development Programme.</p> <p>Results</p> <p>Findings from the logistic model predicting the odds of asymptomatic malaria indicate that children who experienced mild, moderate or severe stunting were not more likely to have asymptomatic malaria than children who were not stunted. Children experiencing anaemia had an increased likelihood (OR = 4.15; 95% CI: 1.92, 8.98) of asymptomatic malaria. Similarly, increased spleen size, which was measured by ultrasound, was also associated with asymptomatic malaria (OR = 2.17; 95% CI: 1.44, 3.28). Fast breathing, sex of the child, and age of the child were not significantly associated with the asymptomatic malaria.</p> <p>Conclusions</p> <p>No significant association between chronic undernutrition and presence of asymptomatic malaria was found. Children who experience anaemia and children who have splenomegaly are more likely to present asymptomatic malaria. Programmes aimed at addressing malaria should continue to include nutritional components, especially components that address anaemia.</p