Escape Systems Research Articles

“Who’s got bars?”: Remixing Intergroup Dialogue Pedagogy through Hip-Hop Feminism

Hip-hop culture serves as a space to correct, prescribe, make known, and show up. Additionally, it offers its users opportunities to do what other spaces cannot, and that is to present a remix of a previously accepted script. Reintroduction can help Black lives, survive, dismantle, and escape systems of thinking that render them invisible and unheard. In this conceptually grounded manuscript, I discuss intergroup dialogue (IGD), with particular attention to IGD pedagogy. Though an important pedagogical strategy in and outside of higher education, IGD pedagogy may be operating to stifle the full expression of Black participants. By way of intervention, I point to possibilities within hip-hop feminism and hip-hop aesthetics to assist educators and facilitators in reimagining IGD pedagogical practice.

Identifying High Velocity Objects in Complex Natural Environments Using Neural Networks

Real-time tracking of highly dynamic and complex objects has been an important aspect of testing in the aerospace industry for several decades. This paper proposes a methodology to identify complex, high velocity targets of interest in a video stream. The targets used in this case are aircrew escape systems, ejection seats, as they are propelled from a dynamic aircraft test bed. Additionally, the testing environment is cluttered with natural and man-made artifacts that affect the background appearance and make the video stream data visually noisy. The object identification problem involves the extraction of critical information from the video stream and feeding it into a neural network that determines the position of the target of interest within the field of view. The results of the computer simulation and analysis were mixed, and show that the proposed methodology is a potentially viable solution but will require continued development.

Development of a Side-Impact (Gy) Neck Injury Criterion for Use in Aircraft and Vehicle Safety Evaluation

OCCUPATIONAL APPLICATIONSIn this study, a lateral impact (Gy accelerative input), upper-neck, multi-axial, neck injury criterion is developed. This criterion could be used to evaluate the safety of U.S. Air Force ejection systems incorporating helmet-mounted displays or other applications where neck injury risk from side impact occurs (e.g., automotive and civilian fixed-wing or rotary-wing aircraft). Development of the criterion was motivated by military aviation, which increasingly incorporates head-supported mass and an expanded pilot population, including smaller pilots (to 47 kg), raising concerns for pilot safety during ejection. Neck injury criteria based on risk functions constructed with human subject and postmortem human subject data allow system designers to quantify the injury risk and design acceptably safe systems. A maximum allowable value for the criterion applicable to U.S. Air Force ejection aircraft is proposed to limit neck injury risk to a 5% probability of moderate injury. However, the underlying risk function allows practitioners to customize the criterion for their desired level of injury risk and injury classification.TECHNICAL ABSTRACT Background: Neck injury remains a concern in ejection seat–equipped military aircraft with the growing use of helmet-mounted displays (HMDs) worn for entire mission durations, as well as in the automotive and civilian aircraft domains. Existing U.S. Department of Defense criteria are overly complex and not clearly tied to injury risk and thus require improvement. Purpose: This study developed a lateral (Gy) impact, upper neck injury criterion for use in the design and test of U.S. Department of Defense escape systems and HMDs. Methods: A multi-axial lateral impact risk function, referred to as MANIC(Gy), was constructed using the survival analysis of a data set that combined human subject (N = 56) and postmortem human (N = 9) data. The human subject data were analyzed to assess criterion sensitivity to anthropometric factors. Additionally, a risk function was applied to quantify the risk associated with changes in HMD mass and acceleration input. Results: A lateral impact (Gy), upper neck injury criterion is proposed, which yields a 5% risk of Abbreviated Injury Scale (AIS) 2 or greater injury at a criterion value of 0.48 (95% confidence intervals of 0.28 and 0.67, respectively). At an injury level of AIS 3 or greater, a risk function was generated that yields a 5% risk at a criterion value of 0.53 (95% confidence intervals of 0.24 and 0.82, respectively). Conclusions: This initial multi-axial risk function could be applied to quantify the risk of neck injury posed by lateral acceleration. Criterion values were correlated with body mass and related anthropometric factors, indicating that the critical values incorporated in this study may require improvement. This same criterion may be useful for analyzing side impact safety in other vehicle systems (e.g., automotive and civilian fixed wing or rotary wing aircraft).

Escape dynamics of many hard disks.

Many-particle effects in escapes of hard disks from a square box via a hole are discussed in a viewpoint of dynamical systems. Starting from N disks in the box at the initial time, we calculate the probability P_{n}(t) for at least n disks to remain inside the box at time t for n=1,2,...,N. At early times, the probabilities P_{n}(t),n=2,3,...,N-1, are described by superpositions of exponential decay functions. On the other hand, after a long time the probability P_{n}(t) shows a power-law decay ∼t^{-2n} for n≠1, in contrast to the fact that it decays with a different power law ∼t^{-n} for cases without any disk-disk collision. Chaotic or nonchaotic properties of the escape systems are discussed by the dynamics of a finite-time largest Lyapunov exponent, whose decay properties are related with those of the probability P_{n}(t).

O2–050 - PD-1 and FOXP3 Predicting the Response to Neoadjuvant-Chemotherapy_(NAC) of Breast Cancer

Background: Recent studies have demonstrated a direct involvement of PD-1 (Programmed cell death 1) and FOXP3 (forkhead box P3) molecules in the immune escape systems of cancer. PD-1 has controlled the over activation of the T lymphocytes, while FOXP3 is a marker for regulatory T cells. We have previously demonstrated the association of tumor infiltrating lymphocytes which is related to T cells and the therapeutic effects to NAC for breast cancer. NAC has become one treatment option for patients with operable breast cancer.

Focused fluid flow systems of the Zhongjiannan Basin and Guangle Uplift, South China Sea

AbstractIn this article, we document a large number of focused fluid escape structures using high quality 2D seismic reflection data and multibeam bathymetry data from a poorly known area at the intersection of the northern South China Sea (SCS) and the western SCS. Three types of focused fluid escape systems are identified and described: mud volcanoes, pipes and associated pockmarks. The mud volcanoes occur singly or as clustered groups. The overpressure driving the mud volcanism is argued herein to be related to the generation of thermogenic hydrocarbons. The clustered distributions are related to localized tectonic uplift in the basin. Pipes mainly occur within the Guangle Uplift or accompany the mud volcano clusters. The pipes located within the Guangle Uplift are attributed to carbonate dissolution caused by hydrothermal fluids. Fluids ascended through these structures and were expelled at the palaeo‐seabed or present seabed forming palaeo‐pockmarks and present‐day pockmarks. Some ‘mega‐pockmarks’ show evidence of enlargement due to bottom currents. The marginal basins of the SCS are petroliferous, with attention gradually shifting to the deep‐water area. Our results show that fluid migration must be taken into account when assessing seabed stability. This analysis also improves our understanding the petroleum geology in the study area, and is also useful for predicating where chemosynthetic ecosystems may be located.

Sensory Activation and Receptive Field Organization of the Lateral Giant Escape Neurons in Crayfish

Crayfish (Procambarus clarkii) have bilateral pairs of giant interneurons that control rapid escape movements in response to predatory threats. The medial giant neurons (MGs) can be made to fire an action potential by visual or tactile stimuli directed to the front of the animal and this leads to an escape tail-flip that thrusts the animal directly backward. The lateral giant neurons (LGs) can be made to fire an action potential by strong tactile stimuli directed to the rear of the animal, and this produces flexions of the abdomen that propel the crayfish upward and forward. These observations have led to the notion that the receptive fields of the giant neurons are locally restricted and do not overlap with each other. Using extra- and intracellular electrophysiology in whole animal preparations of juvenile crayfish, we found that the receptive fields of the LGs are far more extensive than previously assumed. The LGs receive excitatory inputs from descending interneurons originating in the brain; these interneurons can be activated by stimulation of the antenna II nerve or the protocerebral tract. In our experiments, descending inputs alone could not cause action potentials in the LGs, but when paired with excitatory postsynaptic potentials elicited by stimulation of tail afferents, the inputs summed to yield firing. Thus the LG escape neurons integrate sensory information received through both rostral and caudal receptive fields, and excitatory inputs that are activated rostrally can bring the LGs' membrane potential closer to threshold. This enhances the animal's sensitivity to an approaching predator, a finding that may generalize to other species with similarly organized escape systems.

Cockroaches keep predators guessing by using preferred escape trajectories

Antipredator behavior is vital for most animals and calls for accurate timing and swift motion. Whereas fast reaction times [1] and predictable, context-dependent escape-initiation distances [2] are common features of most escape systems, previous work has highlighted the need for unpredictability in escape directions, in order to prevent predators from learning a repeated, fixed pattern [3,4,5]. Ultimate unpredictability would result from random escape trajectories. Although this strategy would deny any predictive power to the predator, it would also result in some escape trajectories toward the threat. Previous work has shown that escape trajectories are in fact generally directed away from the threat, although with a high variability [5,6,7,8]. However, the rules governing this variability are largely unknown. Here, we demonstrate that individual cockroaches (Periplaneta americana, a much-studied model prey species [9,10,11,12,13,14]) keep each escape unpredictable by running along one of a set of preferred trajectories at fixed angles from the direction of the threatening stimulus. These results provide a new paradigm for understanding the behavioral strategies for escape responses, underscoring the need to revisit the neural mechanisms controlling escape directions in the cockroach and similar animal models, and the evolutionary forces driving unpredictable, or ?protean? [3], antipredator behavior.

Migration and venting of deep gases into the ocean through hydrate-choked chimneys offshore Korea

It has recently been recognized that, in addition to low concentrations of widespread natural gas hydrate associated with bottomsimulating seismic refl ectors, highly concentrated hydrate can occur in local seafl oor fl uid venting structures. Such structures extend upward into the regional gas hydrate stability fi eld and sometimes allow gases to escape into the overlying ocean. These hydrate-choked chimneys are especially prospective as an energy resource because they contain high hydrate concentrations. Furthermore, they may be one of the most important conduits into the ocean-atmosphere system for deep methane. We present an analysis of two-dimensional seismic refl ection data from offshore Korea that give a complete picture of gas migrating from a deep source zone to feed hydrate-choked vent structures at the seafl oor. The gases migrate upward through networks of fractures imaged as steep amplitude striations in both diffuse and concentrated distributions. We present an example of a high-fl ux gas vent fed through fracture swarms emanating from a 10‐15-km-wide catchment zone of source gases residing 3‐4 km below the seabed. The geological context and the inferred distribution of hydrate within this feature are consistent with recent models in which seabed gas venting is a consequence of elevated pore fl uid salinities that are produced by a high fl ux of gases migrating independently of the pore water. In contrast, a nearby vent that is not plumbed into the same high-fl ux system appears to be dominated more by gas-rich liquids. We present these two vent structures as type cases for high- and lowfl ux fl uid escape systems in the seabed. Furthermore, we suggest that since the amount of gas trapped as hydrate within the vents is small compared with the amount in the underlying reservoir, the greatest risk for increased methane input to the atmosphere associated with climate-driven oceanic warming is not the melting of hydrate, but an increase in the number of deep reservoirs able to vent gases through the seabed that occurs as the regional gas hydrate stability zone thins.

Cockroaches Keep Predators Guessing by Using Preferred Escape Trajectories

Antipredator behavior is vital for most animals and calls for accurate timing and swift motion. Whereas fast reaction times [1] and predictable, context-dependent escape-initiation distances [2] are common features of most escape systems, previous work has highlighted the need for unpredictability in escape directions, in order to prevent predators from learning a repeated, fixed pattern [3-5]. Ultimate unpredictability would result from random escape trajectories. Although this strategy would deny any predictive power to the predator, it would also result in some escape trajectories toward the threat. Previous work has shown that escape trajectories are in fact generally directed away from the threat, although with a high variability [5-8]. However, the rules governing this variability are largely unknown. Here, we demonstrate that individual cockroaches (Periplaneta americana, a much-studied model prey species [9-14]) keep each escape unpredictable by running along one of a set of preferred trajectories at fixed angles from the direction of the threatening stimulus. These results provide a new paradigm for understanding the behavioral strategies for escape responses, underscoring the need to revisit the neural mechanisms controlling escape directions in the cockroach and similar animal models, and the evolutionary forces driving unpredictable, or "protean"[3], antipredator behavior.

Environment guidelines for EER systems in ice-covered waters

The effects of ice and cold water environments on escape, evacuation, and rescue (EER) systems for offshore structures in ice-covered waters are discussed. The cold region environment influences all aspects of EER system design. Guidance is provided, for a wide range of ice and environmental conditions, on the factors that should be considered in developing an EER system for a structure that is to be operated in ice-covered waters. There is no one EER system that can reliably accommodate all of the requirements for safe evacuation from Arctic structures and several different systems may be required for year-round operation. Furthermore, the most suitable evacuation system will be different for different environmental conditions. Careful design, planning, training, and ongoing maintenance of the EER system are required for these harsh environmental conditions.

Analysis of a Hybrid Dual-Combustion-Chamber Solid-Propellant Gas Generator

Solid-propellantgas generators (SPGGs) have a number of aerospace applications, includingmunitionsdispersion, pilot emergency escape systems, submarinemissile launching,powering actuators and valves, and short-term power supply. Recently, the increased demand for so-called smart automotive airbags has increased the need for SPGG designs capable of real-time, tailorable output. Dual-combustion-chamber gas generators provide several distinct advantagesover single-combustor units in systems where optimumperformance is needed at several operating conditions. The objective of this work is to evaluate the attainable performance characteristics of a proposed dual-combustion-chambergas generator. The work includes a simulation of the transient, thermochemical events associated with the Ž ring of an SPGG. The simulations also include the dynamics of coupled events such as ignition, heterogeneous combustion, and mass discharge. The baseline gas generator being simulated in this work is a hybrid SPGG in ator with two combustion chambers. Studies are made of the distribution of propellant between combustion chambers and the times at which the propellant within each combustion chamber is Ž red.

Continental collision and lateral escape deformation in the lower and upper crust: An example from Caledonide Svalbard

Ductile Caledonian structures of eastern Svalbard and the pattern of brittle deformation in eastern Anatolia are examined in an attempt to understand the different mechanical responses of the upper and the lower crust in collision and lateral escape systems. In Svalbard, Early to Middle Proterozoic basement structures were reworked under amphibolite facies conditions, in Late Silurian time, during the Caledonian orogeny when synmetamorphic ductile to postmetamorphic brittle, left‐lateral shearing was concentrated in narrow zones. The widespread distribution of contractional and elongation structures over the northern and northeastern Svalbard indicates that this deformation was the result of E–W convergence and N–S lateral escape of the whole continental mass along an array of deep crustal shear zones. The combination of vertical shear zones with parallel low‐angle compressional shear zones and associated folds in Ny Friesland represents the ductile or plastic flow response of the lower crust to the orthogonal‐lateral escape setting. The westward escape of the Anatolian block, accompanying the active Arabia‐Eurasia collision, is associated with a 150 km wide zone of thrust faulting and NE–SW sinistral strike‐slip faults along the East Anatolian Fault Zone. Arrays of dextral and sinistral strike‐slip faults with thrust and normal faults between the Eastern Anatolian and the North Anatolian Fault Zones represent an elastic response of the upper crust that is considered to be the superficial equivalent of the ductile flow in the lower crust of Caledonide Svalbard in a convergence‐lateral escape setting.

Computer simulation to assess the performance of a submarine escape system

The operational performance of submarine escape systems is currently assessed mainly by experimental testing, which often cannot fully explain their behaviour. Computer simulation is a well-established technique in the analysis of complicated dynamic systems and when used in conjunction with experimental testing, promises significant advances in both the understanding and the performance evaluation of such systems. This paper describes a simulation study undertaken on a submarine escape system. Details are included regarding the derivation and validation of the simulation model and examples presented showing how simulation can be used for performance assessment and as a design tool.

Biotin staining in the giant fiber systems of the lobster.

The avidin-biotin-complex method is a popular immunocytochemical technique. This method labels consistently a group of neurons in the lobster ventral nerve cord in the absence of primary antibodies. The specific staining is due to a relatively high level of endogenous biotin (or biocytin) in these neurons. These biotin-positive neurons are located in the supraesophageal, thoracic, and abdominal ganglia. Intraaxonal injection of Lucifer yellow followed by Texas red-conjugated streptavidin staining reveals that the neurons are members of the medial giant (MG) and lateral giant (LG) systems, which are important in mediating rapid tail flipping during escape maneuvers. In neuronal somata, staining is restricted to the cytoplasm. Within MG axons, staining appears as punctate, subaxolemmal structures. Preincubating nerve cords in biocytin or direct intraaxonal injection of biocytin enhances staining of these punctate organelles. In LG axons, staining is localized to fragments of braided filamentous structures that also appear to be associated with the axolemma. Preincubation of ventral nerve cords in various concentrations of biocytin results in the appearance of additional groups of stained neurons, suggesting that there are subsets of neurons with specific biocytin-uptake or -retention mechanisms. In the crayfish, biotin-positive staining is confined to the MG neurons; the LG neurons are not stained. In the earthworm, no staining is observed in the MG and LG axon escape systems. In the goldfish, no biotin-staining is seen in the Mauthner neurons and their axons. The significance of specific localization of biotin or biocytin to subsets of neurons is unclear. It may reflect the presence of high levels of biocytin moieties on biotin-dependent enzymes. Biotin is an important cofactor in the catalytic functions of several decarboxylases crucial in energy production and lipogenesis. Axons of the giant fiber systems in lobsters and crayfish may have high energy and fatty acid synthesis requirements. Increased levels of biotin accumulation may also be related to other functions of the giant axon systems, such as the formation of electrical synapses among themselves and with phasic motoneurons.

Interactions of membrane excitability mutations affecting potassium and sodium currents in the flight and giant fiber escape systems of Drosophila.

We have studied the influence of the K(+)-current mutations eag and Sh and the Na(+)-current mutation napts upon two well-defined neural circuits that underlie flight and an escape response in Drosophila, recording from dorsal longitudinal and tergotrochanteral muscles. Mutations of Sh and eag affected refractory period and following frequency, but not latency, of the jump-and-flight escape response. The napts mutation altered these 3 physiological parameters of the "jump" (TTM), but not the "flight" (DLM), branch, suggesting differences in the vulnerability of different circuit components to the mutation. In contrast to their interaction in some other systems, napts did not counteract the effects of eag and Sh upon these physiological parameters in eag Sh; nap triple mutants. In eag Sh double mutants, in which multiple K+ currents may be diminished, flight muscles showed abnormal rhythmic activity not associated with flight, and some flies also had an abnormal wings-down posture. The low-frequency spikes probably originated in the flight muscle motoneurons, but the coordination between muscle fibers during this "non-flight activity" was distinct from flight. Nevertheless, in spite of the presence of this non-flight activity in resting eag Sh flies, those animals with normal wing posture were also able to fly, with a normal pattern of muscle activity. This suggests that in these mutants, the DLM motoneuron circuit is able to switch between two patterns of output, non-flight activity and flight.(ABSTRACT TRUNCATED AT 250 WORDS)

Lobe dynamics and the escape from a potential well

Periodically-forced nonlinear oscillators that permit escape from a potential well frequently possess unstable periodic orbits whose invariant manifolds are homoclinically tangled. The trellises formed by such overlapping manifolds separate the Poincaré plane into regions (calledlobes) whose fates at successive time periods are amenable to analysis. The lobe configurations observed in simple escape systems are discussed, together with their interrelation with the location of periodic orbits and other invariant sets. Three applications of this procedure are illustrated: (i) a numerical technique for localizing the non-wandering set; (ii) a demonstration that the existence of a saddle possessing aboundedhomoclinically tangled unstable manifold branch implies the existence of safe open regions in the global basin of attraction; (iii) the proposal of definitions of global integrity and escape times which may be used to relate safe basin erosion to the evolution of a homoclinic tangle.

Martin‐Baker — at the Forefront of Escape System Technology

THE Company is the most experienced and largest organisation dedicated solely to the design, development and manufacture of aircrew escape systems. It is this dedication to aircrew safety which has enabled the delivery of over 63,000 ejection seats to 81 Air Forces. To date, Martin‐Baker ejection seats have saved some 5,750 aircrew lives.

Safety Topics

The latest expertise in escape systems was shown on the Martin‐Baker stand at the Paris Show, highlighted by the company's Mk 14 which is the world's first microprocessor controlled electronic ejection seat. Currently undergoing testing is the variant for the United States Navy Aircrew Common Ejection Seat (NACES) programme, which will be standard equipment for the F/A Hornet, F‐14 Tomcat, T‐45 Goshawk and A6F Intruder. Versions are also being proposed for the European Figh‐ter Aircraft, French Rafale B and the USAF Advanced tactical Fighter.

Chemical and photographic evaluation of rigid explosive transfer lines

This paper describes the chemical and photographic analyses perfomed on 112 explosive transfer lines used to initiate aircraft emergency escape systems