Development of a low-cost underwater manipulator

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 41).This thesis describes the design, modeling, manufacture, and testing of a low cost, multiple degree-of-freedom underwater manipulator. Current underwater robotic arm technologies are often expensive or limited in functionality. The goal of this research is to produce a multiple degree-of-freedom manipulator utilizing relatively inexpensive, commercial off-the-shelf servo motors. This project is designed for low-payload (< 0.5 kg) and shallow depth operation on a small remotely operated vehicle. A completed underwater manipulator has been built using the new servo housing design. Static and dynamic waterproofing techniques have proven satisfactory, offering a solid design for waterproofing of servo motors. Preliminary tests of the integrated servo arm system indicate that the arm will operate successfully in the underwater environment. This design is anticipated to be used on an underwater vehicle in June 2006, as well as in future undergraduate ocean engineering design subjects.by Lauren Alise Cooney.S.B

Dynamic response and maneuvering strategies of a hybrid autonomous underwater vehicle in hovering

Thesis (S.M. in Ocean Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 87-93).The Odyssey IV autonomous underwater vehicle (AUV) is the next generation of unmanned subsurface robots from the MIT Sea Grant AUV Laboratory. The Odyssey IV AUV has a novel propulsion system, which includes a pair of azimuthing thrusters for maneuvering in surge and heave. An analytical model was developed to describe the complex nonlinear vehicle dynamics, and experiments were performed to refine this model. The fluid dynamics of unsteady azimuthing marine propulsors are largely unstudied, especially for small vehicles like the Odyssey IV AUV. Experiments suggest that thrust developed by an azimuthing propulsor is dependent on the azimuth angle rate of change, and can substantially affect vehicle dynamics. A simple model capturing the effects of azimuthing on the thruster dynamics is developed, and is shown to improve behavior of the model.The use of azimuthing thrusters presents interesting problems and opportunities in maneuvering and control. Nonlinear model predictive control (MPC) is a technique that consists of the real-time optimization of a nonlinear dynamic system model, with the ability to handle constraints and nonlinearities. In this work, several variations of simulated and experimental MPC-based controllers are investigated. The primary challenge in applying nonlinear MPC to the Odyssey IV is solving the time intensive trajectory optimization problem online. Simulations suggest that MPC is able to capitalize on its knowledge of the system, allowing more aggressive trajectories than a traditional PID controller.by Lauren Alise Cooney.S.M.in Ocean Engineerin

Emergency Department Closures: The Critical Case of Reduced Care AccessWithin Rural Populations

In this paper, the researchers analyzed the effects of overcrowding and financial difficulties faced by rural emergency departments, which can lead to closures. To achieve this goal, we relied on a systematic analysis of the rural emergency department system, including the financial aspects, ethical considerations, and patient demographics. The researchers also utilized past evaluated interventions in order to determine methods of creating an efficient emergency department. We found that while there was an increase in emergency department patients, finances have not increased to accommodate overcrowding. This paper contributes to emergency department and rural health literature, as the researchers propose an evidence-based intervention that will minimize overcrowding and utilize finances effectively, while taking into account patient medical knowledge and scheduling

Accessibility of Pregnancy Termination: A Pilot Study of Genetic Counselors and Abortion Providers Throughout the United States

Recent literature suggests that availability and accessibility of pregnancy termination services affects patient care and decision-making. Because of this, there is a need to evaluate the impact of new legislation on accessibility. This study evaluated the accessibility of pregnancy termination throughout the United States by surveying prenatal genetic counselors and abortion providers. 116 responses from currently practicing prenatal genetic counselors and 30 responses from abortion providers within the United States were used in data analysis. Accessibility of pregnancy termination was assessed using the variables of cost, time, and distance. The degree of legislative impact was estimated using Guttmacher Institute’s Policy Trends in the States 2017, which categorizes states into four regions: supportive, middle-ground, hostile, and extremely hostile, based on the number of abortion restrictions enacted. Overall, the findings show some evidence indicating that access to abortion is more limited in states with increased legislation. Genetic counselors in hostile states were more likely to refer patients to outside providers at every evaluated gestational age range than counselors in supportive states, with 89.9% of counselors referring to providers greater than 4 hours away for referrals over 24 weeks gestation compared to 56.5% in supportive states. Counselors in hostile states were also more likely to report factors such as insurance coverage, out of pocket costs, wait times, travel, and the availability of appointments as having an impact on patients’ decisions to terminate a pregnancy than counselors in supportive states

Is it time to stop being crude? Elderly mortality rates in a refugee camp in Maban County, South Sudan

Background: Mortality is a key indicator in defining and monitoring the scale and severity of a complex humanitarian emergency. While collection of age-disaggregated data is advised in guidelines such as the Sphere handbook, in practice data are rarely disaggregated beyond the under-5s. Despite widespread use of prospective mortality surveillance systems in complex emergencies, there are few guidelines on their implementation and limited evidence of their value. In 2012, 68,000 refugees from Sudan settled in Maban County, South Sudan. MSF introduced a community based surveillance system in Jamam camp to monitor mortality and reported causes of death. Observation of a high proportion of deaths in older refugees led to the adaptation of the surveillance system to collect age-specific mortality data. Here we describe the implementation, outcomes and lessons learnt

Differences in Hospital Managers’, Unit Managers’, and Health Care Workers’ Perceptions of the Safety Climate for Respiratory Protection

This article compares hospital managers’ (HM), unit managers’ (UM), and health care workers’ (HCW) perceptions of respiratory protection safety climate in acute care hospitals. The article is based on survey responses from 215 HMs, 245 UMs, and 1,105 HCWs employed by 98 acute care hospitals in six states. Ten survey questions assessed five of the key dimensions of safety climate commonly identified in the literature: managerial commitment to safety, management feedback on safety procedures, coworkers’ safety norms, worker involvement, and worker safety training. Clinically and statistically significant differences were found across the three respondent types. HCWs had less positive perceptions of management commitment, worker involvement, and safety training aspects of safety climate than HMs and UMs. UMs had more positive perceptions of management’s supervision of HCWs’ respiratory protection practices. Implications for practice improvements indicate the need for frontline HCWs’ inclusion in efforts to reduce safety climate barriers and better support effective respiratory protection programs and daily health protection practices

Description of 3,180 courses of chelation with dimercaptosuccinic acid in children ≤ 5 y with severe lead poisoning in Zamfara, Northern Nigeria: a retrospective analysis of programme data.

BACKGROUND: In 2010, Médecins Sans Frontières (MSF) discovered extensive lead poisoning impacting several thousand children in rural northern Nigeria. An estimated 400 fatalities had occurred over 3 mo. The US Centers for Disease Control and Prevention (CDC) confirmed widespread contamination from lead-rich ore being processed for gold, and environmental management was begun. MSF commenced a medical management programme that included treatment with the oral chelating agent 2,3-dimercaptosuccinic acid (DMSA, succimer). Here we describe and evaluate the changes in venous blood lead level (VBLL) associated with DMSA treatment in the largest cohort of children ≤ 5 y of age with severe paediatric lead intoxication reported to date to our knowledge. METHODS AND FINDINGS: In a retrospective analysis of programme data, we describe change in VBLL after DMSA treatment courses in a cohort of 1,156 children ≤ 5 y of age who underwent between one and 15 courses of chelation treatment. Courses of DMSA of 19 or 28 d duration administered to children with VBLL ≥ 45 µg/dl were included. Impact of DMSA was calculated as end-course VBLL as a percentage of pre-course VBLL (ECP). Mixed model regression with nested random effects was used to evaluate the relative associations of covariates with ECP. Of 3,180 treatment courses administered, 36% and 6% of courses commenced with VBLL ≥ 80 µg/dl and ≥ 120 µg/dl, respectively. Overall mean ECP was 74.5% (95% CI 69.7%-79.7%); among 159 inpatient courses, ECP was 47.7% (95% CI 39.7%-57.3%). ECP after 19-d courses (n = 2,262) was lower in older children, first-ever courses, courses with a longer interval since a previous course, courses with more directly observed doses, and courses with higher pre-course VBLLs. Low haemoglobin was associated with higher ECP. Twenty children aged ≤ 5 y who commenced chelation died during the period studied, with lead poisoning a primary factor in six deaths. Monitoring of alanine transaminase (ALT), creatinine, and full blood count revealed moderate ALT elevation in <2.5% of courses. No clinically severe adverse drug effects were observed, and no laboratory findings required discontinuation of treatment. Limitations include that this was a retrospective analysis of clinical data, and unmeasured variables related to environmental exposures could not be accounted for. CONCLUSIONS: Oral DMSA was a pharmacodynamically effective chelating agent for the treatment of severe childhood lead poisoning in a resource-limited setting. Re-exposure to lead, despite efforts to remediate the environment, and non-adherence may have influenced the impact of outpatient treatment. Please see later in the article for the Editors' Summary

Association of blood lead level with neurological features in 972 children affected by an acute severe lead poisoning outbreak in Zamfara State, northern Nigeria.

BACKGROUND: In 2010, Médecins Sans Frontières (MSF) investigated reports of high mortality in young children in Zamfara State, Nigeria, leading to confirmation of villages with widespread acute severe lead poisoning. In a retrospective analysis, we aimed to determine venous blood lead level (VBLL) thresholds and risk factors for encephalopathy using MSF programmatic data from the first year of the outbreak response. METHODS AND FINDINGS: We included children aged ≤5 years with VBLL ≥45 µg/dL before any chelation and recorded neurological status. Odds ratios (OR) for neurological features were estimated; the final model was adjusted for age and baseline VBLL, using random effects for village of residence. 972 children met inclusion criteria: 885 (91%) had no neurological features; 34 (4%) had severe features; 47 (5%) had reported recent seizures; and six (1%) had other neurological abnormalities. The geometric mean VBLLs for all groups with neurological features were >100 µg/dL vs 65.9 µg/dL for those without neurological features. The adjusted OR for neurological features increased with increasing VBLL: from 2.75, 95%CI 1.27-5.98 (80-99.9 µg/dL) to 22.95, 95%CI 10.54-49.96 (≥120 µg/dL). Neurological features were associated with younger age (OR 4.77 [95% CI 2.50-9.11] for 1-<2 years and 2.69 [95%CI 1.15-6.26] for 2-<3 years, both vs 3-5 years). Severe neurological features were seen at VBLL <105 µg/dL only in those with malaria. INTERPRETATION: Increasing VBLL (from ≥80 µg/dL) and age 1-<3 years were strongly associated with neurological features; in those tested for malaria, a positive test was also strongly associated. These factors will help clinicians managing children with lead poisoning in prioritising therapy and developing chelation protocols

On-Orbit Data and Validation of Astra\u27s ACE Electric Propulsion System

The first ACE propulsion system reached orbit on July 1st 2021 as part of Spaceflight’s demonstration of the Sherpa-LTE all-electric Orbital Transfer Vehicle (OTV). We are now able to share on-orbit data and have successfully verified the on-orbit performance of the ACE propulsion system, using xenon propellent. The mission objective was to lower altitude and use on-orbit data to derive performance, correlating the propulsion system’s performance to ground test data. The demonstration consisted of activating the propulsion system for 5- minute durations at a total input power of 340 W into the Power Processing Unit (PPU). Altitude change and propellant usage were used to derive thrust and total specific impulse. On-orbit performance is compared to ground test data in Table 1. Averaged performance is within one standard deviation of ground test data. Astra considers this a validation of system performance, as well as the ground test facilities used to test propulsion systems. On-orbit thrust has a large standard deviation as a result of the limited data sampling rate and measurement errors, rather than variability in thruster performance. Figure 1 shows the thruster operating on-orbit. The Astra team gratefully acknowledges the support of Spaceflight, Inc., the U.S. Air Force, and Defense Innovation Unit (DIU) without which this mission would not have been possible

The Lantern, 2021-2022

No More Buses through El Paso • A Woman\u27s World • The Angel of Tragedy • A Victim of Circumstance • Ace of Hearts • Ghost Light • Missing Diamonds • The Upside-Down House: A Dialogue with the Self • What is Chronic Pain? • A Sunny Day in Sinkhole • Extra Marshmallows • Fourth Wall Broken • Hemlock • In the Comfort of Others • Lasting Impressions • Let\u27s Do the Time Warp Again • One Last Afternoon • Space Invaders • The Dogwood Tree • An Ode to Poppies • Charlotte\u27s Web • Crab • Crossing • Dandelions • Dandelion Sandwich • Grizzly Hood • Help Wanted • I Gave Way • I\u27m not who you wanted but maybe one day I can be • Kneeling • Lemon Cookies • Lies • Method Acting • Moment of Tranquility • Our Home • Overthinking • Sea Glass • Seasonal • Thirty-Two (No Spares) • The Autumn Beast • The Miller\u27s Daughter • Theodore • To the Earring I Left Behind in Your Carpet • Virginia • Waltzing • Yellow House • 1/25 British Monarch • Cracked • In the Shadows • Jewelwing • Life on the Wing • O\u27 Captain my Captain • Stars Above the Bay • The Common Fall • Tom • Cats + Crowshttps://digitalcommons.ursinus.edu/lantern/1190/thumbnail.jp