Water Impact Prediction Tool for Recoverable Rockets

Reusing components from a rocket launch can be cost saving. NASA's space shuttle system has reusable components that return to the Earth and impact the ocean. A primary example is the Space Shuttle Solid Rocket Booster (SRB) that descends on parachutes to the Earth after separation and impacts the ocean. Water impact generates significant structural loads that can damage the booster, so it is important to study this event in detail in the design of the recovery system. Some recent examples of damage due to water impact include the Ares I-X First Stage deformation as seen in Figure 1 and the loss of the SpaceX Falcon 9 First Stage.To ensure that a component can be recovered or that the design of the recovery system is adequate, an adequate set of structural loads is necessary for use in failure assessments. However, this task is difficult since there are many conditions that affect how a component impacts the water and the resulting structural loading that a component sees. These conditions include the angle of impact with respect to the water, the horizontal and vertical velocities, the rotation rate, the wave height and speed, and many others. There have been attempts to simulate water impact. One approach is to analyze water impact using explicit finite element techniques such as those employed by the LS-Dyna tool [1]. Though very detailed, this approach is time consuming and would not be suitable for running Monte Carlo or optimization analyses. The purpose of this paper is to describe a multi-body simulation tool that runs quickly and that captures the environments a component might see. The simulation incorporates the air and water interaction with the component, the component dynamics (i.e. modes and mode shapes), any applicable parachutes and lines, the interaction of winds and gusts, and the wave height and speed. It is capable of quickly conducting Monte Carlo studies to better capture the environments and genetic algorithm optimizations to reproduce a flight

Enhancing the thermal design and optimization of SOFC technology

M.S.William J. Wepfe

ADVANCING FUEL CELLS TECHNOLOGY VIA ANALOGOUS HEAT EXCHANGER DESIGN PRINCIPLES/7083 (Faxes)

Abstract Fuel cells and heat exchangers have numerous similarities. Both technologies are used to produce an "energy-in-transit." Heat exchangers foster thermal transport (heat) as a result of thermal potential differences between streams; fuel cells foster charge transport across electrodes (current leading to power) as a result of electrochemical/electric potential differences between the reactant streams and fuel cell electrodes. Additional analogs include series resistance formulations, active regions for transport phenomena and pertinent capacity rates. These similarities have motivated the extension of heat exchanger design philosophies to fuel cells development. Pilot simulations have been done wherein solid oxide fuel cell geometries and process settings are being optimized via electrochemical pinch points, electroactive area optimization (patterned after optimal UA allocation within heat exchangers), and electrode "fins" for diminished polarization. The prevailing theme has been to bridge methodologies from the mature field of heat exchanger design to improve fuel cell design practices

Idiosyncratic variables affecting functional analysis outcomes: A review (2001-2010)

Although typical functional analyses often produce clear outcomes, some studies have reported ambiguous results that cannot be interpreted. Such undifferentiated outcomes may occur if test conditions do not include relevant antecedent or consequent events. Clinicians then may try to modify the functional analysis conditions to include those events. Hanley, Iwata, and McCord (2003) reviewed the functional analysis literature through the year 2000 and described idiosyncratic variables included in modified functional analyses. The objective of the present review was to present a quantitative analysis of idiosyncratic antecedents and consequences in modified functional analyses during the past decade (2001 to 2010). We discuss the range of stimulus parameters tested and the assessment strategies used for informing the modified analysis conditions

Preventable hand injuries: A national audit

Summary: Little is known of the scale of avoidable injuries presenting to medical services on a national level in the UK. This study aimed to assess the type and incidence of preventable wrist and hand injuries (as defined by the core research team) at a national level in the UK. 28 UK hospitals undertook a service evaluation of all hand trauma cases presenting to their units over a 2 week period in early 2021 identifying demographical and aetiological information about injuries sustained. 1909 patients were included (184 children) with a median age of 40 (IQR 25-59) years. The commonest five types of injury were fractures of the wrist; single phalangeal or metacarpal fractures; fingertip injuries; and infection, with the most common mechanisms being mechanical falls and manual labour. This is the first extensive survey of preventable hand injuries in the UK, identifying a need for further work into prevention to reduce healthcare burden and cost. 50% of injuries presenting to hand surgeons are preventable, with the most common injuries being single fractures of the wrist, phalanx and metacarpal. Few preventable injuries were related to alcohol or narcotic intoxication. Further research is needed to identify how to initiate injury prevention measures for hand injuries, particularly focussed towards hand fracture prevention

Chronic Sub-lethal Effects Observed in Wild-Caught Fishes Following Two Major Oil Spills in the Gulf of Mexico: \u3cem\u3eDeepwater Horizon\u3c/em\u3e and Ixtoc 1

During and subsequent to major oil spill events, considerable attention focuses on charismatic and economic megafauna – and especially fishes – and visual manifestations of impacts upon them. Beginning with a series of tanker accidents occurring in Europe and the USA in the 1970s–1990s, greater awareness of the potential for both acute and chronic sub-lethal impacts on fish populations has focused on exposure to polycyclic aromatic hydrocarbons (PAHs). The ambiguity of acute impacts observed during the Deepwater Horizon and Ixtoc 1 incidents has promoted considerable new research on alternative toxic endpoints that portend short- and long-term sub-lethal outcomes that influence the overall fitness of exposed populations. Laboratory-based exposure studies have traditionally focused on acute mortality-based endpoints (e.g., lethal concentrations at which 50% of the population dies = LC50) and observed at test concentrations normally exceeding environmentally relevant concentrations in real-world spills. Consequently, using laboratory-based toxicity experiments can be problematic inferring impacts on wild fish populations. In this chapter we review historical and more recent information documenting changes in abundance, recruitment, habitat use, population dynamics, trophic changes, and various physiologically based sub-lethal effects on oil-exposed fishes and especially consider research undertaken following the Deepwater Horizon and Ixtoc 1 spills in the Gulf of Mexico