Differential effects of cough, valsalva, and continence status on vesical neck movement.

PubMed

Howard, D; Miller, J M; Delancey, J O; Ashton-Miller, J A

2000-04-01

We tested the null hypothesis that vesical neck descent is the same during a cough and during a Valsalva maneuver. We also tested the secondary null hypothesis that differences in vesical neck mobility would be independent of parity and continence status. Three groups were included: 17 nulliparous continent (31.3 +/- 5.6; range 22-42 years), 18 primiparous continent (30.4 +/- 4.3; 24-43), and 23 primiparous stress-incontinent (31.9 +/- 3.9; 25-38) women. Measures of vesical neck position at rest and during displacement were obtained by ultrasound. Abdominal pressures were recorded simultaneously using an intravaginal microtransducer catheter. To control for differing abdominal pressures, the stiffness of the vesical neck support was calculated by dividing the pressure exerted during a particular effort by the urethral descent during that effort. The primiparous stress-incontinent women displayed similar vesical neck mobility during a cough effort and during a Valsalva maneuver (13.8 mm compared with 14.8 mm; P =.49). The nulliparous continent women (8.2 mm compared with 12.4 mm; P =. 001) and the primiparous continent women (9.9 mm compared with 14.5 mm; P =.002) displayed less mobility during a cough than during a Valsalva maneuver despite greater abdominal pressure during cough. The nulliparas displayed greater pelvic floor stiffness during a cough compared with the continent and incontinent primiparas (22.7, 15.5, 12.2 cm H(2)O/mm, respectively; P =.001). There are quantifiable differences in vesical neck mobility during a cough and Valsalva maneuver in continent women. This difference is lost in the primiparous stress-incontinent women.

Valsalva's maneuver revisited: a quantitative method yielding insights into human autonomic control

NASA Technical Reports Server (NTRS)

Smith, M. L.; Beightol, L. A.; Fritsch-Yelle, J. M.; Ellenbogen, K. A.; Porter, T. R.; Eckberg, D. L.

1996-01-01

Seventeen healthy supine subjects performed graded Valsalva maneuvers. In four subjects, transesophageal echographic aortic cross-sectional areas decreased during and increased after straining. During the first seconds of straining, when aortic cross-sectional area was declining and peripheral arterial pressure was rising, peroneal sympathetic muscle neurons were nearly silent. Then, as aortic cross-sectional area and peripheral pressure both declined, sympathetic muscle nerve activity increased, in proportion to the intensity of straining. Poststraining arterial pressure elevations were proportional to preceding increases of sympathetic activity. Sympathetic inhibition after straining persisted much longer than arterial and right atrial pressure elevations. Similarly, R-R intervals changed in parallel with peripheral arterial pressure, until approximately 45 s after the onset of straining, when R-R intervals were greater and arterial pressures were smaller than prestraining levels. Our conclusions are as follows: opposing changes of carotid and aortic baroreceptor inputs reduce sympathetic muscle and increase vagal cardiac motor neuronal firing; parallel changes of barorsensory inputs provoke reciprocal changes of sympathetic and direct changes of vagal firing; and pressure transients lasting only seconds reset arterial pressure-sympathetic and -vagal response relations.

Sex Differences in Insular Cortex Gyri Responses to the Valsalva Maneuver.

PubMed

Macey, Paul M; Rieken, Nicholas S; Kumar, Rajesh; Ogren, Jennifer A; Middlekauff, Holly R; Wu, Paula; Woo, Mary A; Harper, Ronald M

2016-01-01

Sex differences in autonomic regulation may underlie cardiovascular disease variations between females and males. One key autonomic brain region is the insular cortex, which typically consists of five main gyri in each hemisphere, and shows a topographical organization of autonomic function across those gyri. The present study aims to identify possible sex differences in organization of autonomic function in the insula. We studied brain functional magnetic resonance imaging (fMRI) responses to a series of four 18-s Valsalva maneuvers in 22 healthy females (age ± SD: 50.0 ± 7.9 years) and 36 healthy males (45.3 ± 9.2 years). Comparisons of heart rate (HR) and fMRI signals were performed with repeated measures ANOVA (threshold P < 0.05 for all findings). All subjects achieved the target 30 mmHg expiratory pressure for all challenges. Typical HR responses were elicited by the maneuver, including HR increases from ~4 s into the strain period (Phase II) and rapid declines to below baseline 5-10 s, following strain release (Phase IV). Small, but significant, sex differences in HR percent change occurred during the sympathetic-dominant Phase II (female < male) and parasympathetic-dominant Phase IV (female > male, i.e., greater undershoot in males). The insular cortices showed similar patterns in all gyri, with greater signal decreases in males than females. Both sexes exhibited an anterior-posterior topographical organization of insular responses during Phase II, with anterior gyri showing higher responses than more posterior gyri. The exception was the right anterior-most gyrus in females, which had lower responses than the four other right gyri. Responses were lateralized, with right-sided dominance during Phase II in both sexes, except the right anterior-most gyrus in females, which showed lower responses than the left. The findings confirm the anterior and right-sided sympathetic dominance of the insula. Although sex differences

Leftward bulging of atrial septum is provoked by nitroglycerin and by sustained valsalva strain.

PubMed

Johansson, Magnus C; Guron, Cecilia Wallentin

2014-10-01

The motion of the interatrial septum primum (septum) is dependent on the interatrial pressure relation, normally with slightly higher pressure in the left atrium and the septum bulging toward the right atrium. The aim of this study was to explore the physiologic mechanisms that reverse interatrial pressures and provoke leftward bulging of septum (LBA). The hypothesis was that both left ventricular unloading with nitroglycerin and sustained Valsalva strain would independently provoke LBA and that their combination would further intensify the effect. Prospectively collected transesophageal echocardiography recordings from 13 patients with obstructive sleep apnea were retrospectively analyzed for the presence or absence of LBA during resting respiration and during Valsalva strain. In each condition, LBA beats were counted at time points before and after nitroglycerin spray had been administered, which enabled a comparison of the independent effects and the combined effect of the nitroglycerin and the Valsalva maneuver. An LBA beat was defined as a heartbeat displaying any LBA during the cardiac cycle. Nitroglycerin increased the proportion of LBA beats significantly during resting respiration, from 21 ± 27% to 54 ± 43% (P = .008). During Valsalva strain, the proportion increased with nitroglycerin spray from 48 ± 21% to 80 ± 17% (P = .001). After nitroglycerin administration, LBA occurred in at least three beats during strain in all Valsalva periods. Unloading of the left ventricle by nitroglycerin administration and by sustained Valsalva strain independently provoked LBA. The combination of these two interventions further intensified the effect. Copyright © 2014 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

Differences in the Biometry of the Levator Hiatus at Rest, During Contraction, and During Valsalva Maneuver Between Women With and Without Provoked Vestibulodynia Assessed by Transperineal Ultrasound Imaging.

PubMed

Thibault-Gagnon, Stéphanie; McLean, Linda; Goldfinger, Corrie; Pukall, Caroline; Chamberlain, Susan

2016-02-01

Pelvic floor muscle (PFM) involvement is suspected in the pathophysiology of provoked vestibulodynia (PVD); however, the underlying mechanisms are unclear. PFM morphology can be inferred from the biometry of the levator hiatus determined through dynamic ultrasound imaging. The aim of this study was to determine the nature of PFM involvement in women with PVD via an evaluation of the biometry of the levator hiatus at rest, upon maximal voluntary contraction (MVC) of the PFMs, and upon maximal Valsalva maneuver (MVM). Thirty-eight women with PVD and 39 asymptomatic controls were imaged using 3D transperineal ultrasound. Levator hiatal dimensions (area; left-right [LR] and anteroposterior [AP] diameters) were measured at rest, on MVC, and on MVM. Differences in hiatal dimensions and in relative changes in dimensions from rest to MVC and from rest to MVM were compared between groups using separate 1-way analyses of variance for each measure and task. Analysis of covariance models were used to investigate the impact of levator hiatal dimensions at rest on the relative changes in the levator hiatal dimensions during MVC and MVM. Levator hiatal area, LR, and AP diameters, at rest, on MVC, and on MVM were the main outcome measures. Relative changes in hiatal dimensions were assessed as the percent change in hiatal area, LR diameter, and AP diameter. In comparison with controls, women with PVD had smaller hiatal areas at rest, on MVC, and on MVM, concurrent with smaller LR diameters on MVM. Women with PVD had a significantly smaller change in hiatal area on MVM than controls, but no differences were evident on MVC. In both groups, smaller levator hiatal dimensions at rest were associated with smaller relative decreases in dimensions on MVC and larger relative increases in dimensions on MVM. In comparison to controls, women with PVD appear to have narrower levator hiatus' and less capacity to distend their hiatus on Valsalva. The state of the PFMs at rest appears to

Cardiac and Vascular Responses to Thigh Cuffs and Respiratory Maneuvers on Crewmembers of the International Space Station

NASA Technical Reports Server (NTRS)

Hamilton, Douglas; Sargsyan, Ashot E.; Garcia, Kathleen; Ebert, Douglas; Whitson, Peggy A.; Feiveson, Alan; Alferova, Irina V.; Dulchavsky, Scott A.; Matveev, Vladimir P.; Bogomolov, Valery V.;

The Valsalva manoeuvre versus tourniquet for venipuncture.

PubMed

Villa, Gianluca; Chelazzi, Cosimo; Giua, Rosa; Lavacchini, Laura; Tofani, Lorenzo; Zagli, Giovanni; Barbani, Francesco; De Gaudio, A Raffaele; Romagnoli, Stefano; Pinelli, Fulvio

2018-03-01

During ultrasound-guided cannulation, venous filling is required for venipuncture. Tourniquet with an elastic tube at the axilla is the most common method to induce venous stasis for cannulation of the deep veins of the arm. Although effective, this method might be associated with short- and long-term complications. Valsalva manoeuvre has been used to produce venous filling in other extrathoracic veins. The aim of this observational study is to demonstrate the effect of Valsalva manoeuvre in respect of the elastic tourniquet on venous distention during echography-guided cannulation of the deep veins of the arm. Sixty-nine patients scheduled for cannulation of basilic or brachial vein were prospectively observed. Vein diameters were recorded at rest and after 10 s of Valsalva or tourniquet placement. The mean difference between basilic vein diameters during tourniquet and Valsalva manoeuvre was 0.006 mm (95% confidence interval = -inf, 0.09) with a standard deviation of 0.5 mm (95% confidence interval = 0.5, 0.7; p > 0.01). The mean difference between brachial vein diameters during tourniquet and Valsalva manoeuvre was 0.04 mm (95% confidence interval = -0.23, 0.15) with a standard deviation of 0.8 mm (95% confidence interval = 0.7, 0.9; p > 0.01). This increase in cross-sectional basilic and brachial vein diameters was not different to that obtained with the elastic tube tourniquet.

Modified Valsalva test differentiates primary from secondary cough headache.

PubMed

Lane, Russell J M; Davies, Paul T G

2013-03-28

The current definition of cough headache includes provocation of the symptom by Valsalva manoeuvre, and it is generally believed that all cough headache results from a sudden increase in intracranial pressure. We sought to question that presumption and to determine whether the Valsalva test might distinguish primary from secondary cough headache. We examined 16 consecutive cough headache patients using a modified Valsalva test (exhalation into the connecting tube of a standard anaeroid sphygmomanometer to 60 mm Hg for 10 seconds). A positive response was recorded if the manoeuvre provoked headache. All patients subsequently underwent brain MRI. None of the patients had neurological signs. Eleven had positive modified Valsalva tests. Ten were found subsequently to have posterior fossa pathologies (secondary cough headache: 8 Chiari Type 1 malformations, 2 posterior fossa meningiomas). The cough headache was relieved following surgery in all cases. One patient with a positive Valsalva test had an apparently normal brain MRI but measurements of hindbrain and posterior fossa dimensions were consistent with 'posterior fossa crowdedness'. The remaining 5 patients had negative (4 patients) or equivocal (1 patient) Valsalva tests and normal MRI scans (primary cough headache). These findings suggest that secondary cough headache results from a transient increase in intracranial CSF pressure during exertion in the presence of obstruction to normal cerebrospinal fluid dynamics. The modified Valsalva test can also determine whether tonsillar herniation found on brain MRI is symptomatic. Primary cough headache appears to be caused by a different mechanism, possibly through congestion of the orbital venous plexus in the presence of jugular venous incompetence and a reduced threshold for trigeminal sensory activation.

Agreement and reliability of pelvic floor measurements during rest and on maximum Valsalva maneuver using three-dimensional translabial ultrasound and virtual reality imaging.

PubMed

Speksnijder, L; Oom, D M J; Koning, A H J; Biesmeijer, C S; Steegers, E A P; Steensma, A B

2016-08-01

Imaging of the levator ani hiatus provides valuable information for the diagnosis and follow-up of patients with pelvic organ prolapse (POP). This study compared measurements of levator ani hiatal volume during rest and on maximum Valsalva, obtained using conventional three-dimensional (3D) translabial ultrasound and virtual reality imaging. Our objectives were to establish their agreement and reliability, and their relationship with prolapse symptoms and POP quantification (POP-Q) stage. One hundred women with an intact levator ani were selected from our tertiary clinic database. Information on clinical symptoms were obtained using standardized questionnaires. Ultrasound datasets were analyzed using a rendered volume with a slice thickness of 1.5 cm, at the level of minimal hiatal dimensions, during rest and on maximum Valsalva. The levator area (in cm(2) ) was measured and multiplied by 1.5 to obtain the levator ani hiatal volume (in cm(3) ) on conventional 3D ultrasound. Levator ani hiatal volume (in cm(3) ) was measured semi-automatically by virtual reality imaging using a segmentation algorithm. Twenty patients were chosen randomly to analyze intra- and interobserver agreement. The mean difference between levator hiatal volume measurements on 3D ultrasound and by virtual reality was 1.52 cm(3) (95% CI, 1.00-2.04 cm(3) ) at rest and 1.16 cm(3) (95% CI, 0.56-1.76 cm(3) ) during maximum Valsalva (P < 0.001). Both intra- and interobserver intraclass correlation coefficients were ≥ 0.96 for conventional 3D ultrasound and > 0.99 for virtual reality. Patients with prolapse symptoms or POP-Q Stage ≥ 2 had significantly larger hiatal measurements than those without symptoms or POP-Q Stage < 2. Levator ani hiatal volume at rest and on maximum Valsalva is significantly smaller when using virtual reality compared with conventional 3D ultrasound; however, this difference does not seem clinically important. Copyright © 2015 ISUOG. Published by

Acute Modifications of Circulating Volume and Respiratory Maneuvers in the Cardiovascular Assessment of Long-Duration Crewmembers

NASA Technical Reports Server (NTRS)

Bogomolov, V. V.; Alferova, I. V.; Dulchavsky, S. A.; Garcia, K. M.; Martin, D. S.; Melton, S. L.; Sargsyan, A. E.; Hamilton, D. R.; Duncan, J. M.

2010-01-01

This U.S. - Russian project is aimed at improved assessment of cardiac and vascular parameters associated with circulating volume and its distribution in long-duration space flight. Objective responses to modified Valsalva and Mueller maneuvers were measured by cardiac and vascular ultrasound before, during, and after temporary volume redistribution by means of Braslet-M thigh occlusion cuffs (Russia). Braslet-M cuffs are custom fitted to each crewmember prior to launch on the Soyuz as a Russian countermeasure for space adaptation fluid shifts

Acquired Large Calcified Unruptured Sinus of Valsalva Aneurysm.

PubMed

Park, Sang-Hyun; Seol, Sang-Hoon; Seo, Guang-Won; Song, Pil-Sang; Kim, Dong-Kie; Kim, Ki-Hun; Kim, Doo-Il

2015-11-01

Acquired aneurysms of the sinus of Valsalva are rare. They are caused by infections such as tuberculosis, syphilis and endocarditis, as well as atherosclerosis and traumatic injury. They may be asymptomatic and incidentally discovered. We present a rare case of a large acquired calcified unruptured aneurysm of the right coronary sinus of Valsalva that was compressing the right ventricular outflow tract. Copyright © 2015 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Anterior but not posterior choroid changed before and during Valsalva manoeuvre in healthy Chinese: a UBM and SS-OCT study

PubMed Central

Li, Fei; Gao, Kai; Li, Xingyi; Chen, Shida; Huang, Wenbin; Zhang, Xiulan

2017-01-01

Purpose To determine if the anterior choroid is involved in ocular change during the Valsalva manoeuvre (VM). Materials and methods Fifty-three healthy volunteers aged 18–65 years with normal visual field test results and no history of intraocular pressure (IOP) exceeding 21 mm Hg were recruited. Anterior and posterior choroidal changes before and during VM were recorded by ultrasound microscope and swept-source optical coherence tomography, respectively. Parameters of the anterior segment included ciliary body thickness (CBT0), thickness of the choroid at a distance of 4 mm from the root of the iris (CT4), anterior placement of the ciliary body (APCB) and trabecular–ciliary angle (TCA). Thickness of different layers of retina and posterior choroid were also measured and compared before and during VM. IOP, blood pressure (BP), heart rate (HR), axial length, spherical equivalent refractive error and pupil diameter (PD) were also recorded and analysed. Results VM caused elevated IOP, systolic BP, diastolic BP and increased HR. There was a significant increase in anterior parameters including CBT0, CT4 and APCB (p<0.001), but not in TCA or PD (p>0.05). The mean change of CBT0, CT4 and APCB were: from 1.00±0.09 mm to 1.11±0.10 mm (p<0.001), from 0.29±0.04 mm to 0.36±0.05 mm (p<0.001), from 0.76±0.11 mm to 0.88±0.13 mm (p<0.001), respectively. However, there is no significant change in posterior choroid (from 215.74±60.23 µm to 214.82±61.32 µm, p=0.17). Conclusion We found that VM did not affect the posterior choroid, but it did cause thickening of the anterior choroid and the ciliary body, both of which led to a larger anterior placement of the ciliary body and a narrowed anterior chamber. The anterior (but not the posterior) choroid could be related to IOP elevation and a narrowed anterior chamber in primary angle closure diseases. PMID:28432110

Validity of the Water Hammer Formula for Determining Regional Aortic Pulse Wave Velocity: Comparison of One-Point and Two-Point (Foot-to-Foot) Measurements Using a Multisensor Catheter in Human.

PubMed

Hanya, Shizuo

2013-01-01

Lack of high-fidelity simultaneous measurements of pressure and flow velocity in the aorta has impeded the direct validation of the water-hammer formula for estimating regional aortic pulse wave velocity (AO-PWV1) and has restricted the study of the change of beat-to-beat AO-PWV1 under varying physiological conditions in man. Aortic pulse wave velocity was derived using two methods in 15 normotensive subjects: 1) the conventional two-point (foot-to-foot) method (AO-PWV2) and 2) a one-point method (AO-PWV1) in which the pressure velocity-loop (PV-loop) was analyzed based on the water hammer formula using simultaneous measurements of flow velocity (Vm) and pressure (Pm) at the same site in the proximal aorta using a multisensor catheter. AO-PWV1 was calculated from the slope of the linear regression line between Pm and Vm where wave reflection (Pb) was at a minimum in early systole in the PV-loop using the water hammer formula, PWV1 = (Pm/Vm)/ρ, where ρ is the blood density. AO-PWV2 was calculated using the conventional two-point measurement method as the distance/traveling time of the wave between 2 sites for measuring P in the proximal aorta. Beat-to-beat alterations of AO-PWV1 in relationship to aortic pressure and linearity of the initial part of the PV-loop during a Valsalva maneuver were also assessed in one subject. The initial part of the loop became steeper in association with the beat-to-beat increase in diastolic pressure in phase 4 during the Valsalva maneuver. The linearity of the initial part of the PV-loop was maintained consistently during the maneuver. Flow velocity vs. pressure in the proximal aorta was highly linear during early systole, with Pearson's coefficients ranging from 0.9954 to 0.9998. The average values of AO-PWV1 and AO-PWV2 were 6.3 ± 1.2 and 6.7 ± 1.3 m/s, respectively. The regression line of AO-PWV1 on AO-PWV2 was y = 0.95x + 0.68 (r = 0.93, p <0.001). This study concluded that the water-hammer formula (one-point method) provides

Regulation of the spoVM gene of Bacillus subtilis.

PubMed

Le, Ai Thi Thuy; Schumann, Wolfgang

2008-11-01

The spoVM gene of Bacillus subtilis codes for a 26 amino-acid peptide that is essential for sporulation. Analysis of the expression of the spoVM gene revealed that wild-type cells started to synthesize a spoVM-specific transcript at t2, whereas the SpoVM peptide accumulated at t4. Both the transcript and the peptide were absent from an spoVM knockout strain. The 5' untranslated region of the spoVM transcript increased expression of SpoVM. Possible regulation mechanisms are discussed.

New directions in the CernVM file system

NASA Astrophysics Data System (ADS)

Blomer, Jakob; Buncic, Predrag; Ganis, Gerardo; Hardi, Nikola; Meusel, Rene; Popescu, Radu

2017-10-01

The CernVM File System today is commonly used to host and distribute application software stacks. In addition to this core task, recent developments expand the scope of the file system into two new areas. Firstly, CernVM-FS emerges as a good match for container engines to distribute the container image contents. Compared to native container image distribution (e.g. through the “Docker registry”), CernVM-FS massively reduces the network traffic for image distribution. This has been shown, for instance, by a prototype integration of CernVM-FS into Mesos developed by Mesosphere, Inc. We present a path for a smooth integration of CernVM-FS and Docker. Secondly, CernVM-FS recently raised new interest as an option for the distribution of experiment conditions data. Here, the focus is on improved versioning capabilities of CernVM-FS that allows to link the conditions data of a run period to the state of a CernVM-FS repository. Lastly, CernVM-FS has been extended to provide a name space for physics data for the LIGO and CMS collaborations. Searching through a data namespace is often done by a central, experiment specific database service. A name space on CernVM-FS can particularly benefit from an existing, scalable infrastructure and from the POSIX file system interface.

Should the annular tendon of the eye be named 'annulus of Zinn' or 'of Valsalva'?

PubMed

Zampieri, Fabio; Marrone, Daniela; Zanatta, Alberto

2015-02-01

The annular tendon is commonly named 'annulus of Zinn', from the German anatomist and botanist Johann Gottfried Zinn (1727-1759) who described this structure in his Descriptio anatomica oculi humani (Anatomical Description of the Human Eye, 1755). This structure, however, had been previously discovered not by Zinn, but by Antonio Maria Valsalva (1666-1723) some decades before the publication of Zinn, in his Dissertatio anatomica prima and Dissertatio anatomica altera (First and Second Anatomical Dissertations), inside Valsalva's Opera omnia published in 1740. We advance that this structure could be re-named such as 'annulus of Valsalva-Zinn' because Valsalva, even making a mistake in its functional interpretation, first described this anatomical structure. Likewise, Valsalva, with his discovery, advanced a revolutionary idea for that time on the usefulness of anatomy for clinic and pathology. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Nonlinear assessment of cerebral autoregulation from spontaneous blood pressure and cerebral blood flow fluctuations.

PubMed

Hu, Kun; Peng, C K; Czosnyka, Marek; Zhao, Peng; Novak, Vera

2008-03-01

Cerebral autoregulation (CA) is an most important mechanism responsible for the relatively constant blood flow supply to brain when cerebral perfusion pressure varies. Its assessment in nonacute cases has been relied on the quantification of the relationship between noninvasive beat-to-beat blood pressure (BP) and blood flow velocity (BFV). To overcome the nonstationary nature of physiological signals such as BP and BFV, a computational method called multimodal pressure-flow (MMPF) analysis was recently developed to study the nonlinear BP-BFV relationship during the Valsalva maneuver (VM). The present study aimed to determine (i) whether this method can estimate autoregulation from spontaneous BP and BFV fluctuations during baseline rest conditions; (ii) whether there is any difference between the MMPF measures of autoregulation based on intra-arterial BP (ABP) and based on cerebral perfusion pressure (CPP); and (iii) whether the MMPF method provides reproducible and reliable measure for noninvasive assessment of autoregulation. To achieve these aims, we analyzed data from existing databases including: (i) ABP and BFV of 12 healthy control, 10 hypertensive, and 10 stroke subjects during baseline resting conditions and during the Valsalva maneuver, and (ii) ABP, CPP, and BFV of 30 patients with traumatic brain injury (TBI) who were being paralyzed, sedated, and ventilated. We showed that autoregulation in healthy control subjects can be characterized by specific phase shifts between BP and BFV oscillations during the Valsalva maneuver, and the BP-BFV phase shifts were reduced in hypertensive and stroke subjects (P < 0.01), indicating impaired autoregulation. Similar results were found during baseline condition from spontaneous BP and BFV oscillations. The BP-BFV phase shifts obtained during baseline and during VM were highly correlated (R > 0.8, P < 0.0001), showing no statistical difference (paired-t test P > 0.47). In TBI patients there were strong correlations

Nonlinear Assessment of Cerebral Autoregulation from Spontaneous Blood Pressure and Cerebral Blood Flow Fluctuations

PubMed Central

Peng, C. K.; Czosnyka, Marek; Zhao, Peng

2009-01-01

Cerebral autoregulation (CA) is an most important mechanism responsible for the relatively constant blood flow supply to brain when cerebral perfusion pressure varies. Its assessment in nonacute cases has been relied on the quantification of the relationship between noninvasive beat-to-beat blood pressure (BP) and blood flow velocity (BFV). To overcome the nonstationary nature of physiological signals such as BP and BFV, a computational method called multimodal pressure-flow (MMPF) analysis was recently developed to study the nonlinear BP–BFV relationship during the Valsalva maneuver (VM). The present study aimed to determine (i) whether this method can estimate autoregulation from spontaneous BP and BFV fluctuations during baseline rest conditions; (ii) whether there is any difference between the MMPF measures of autoregulation based on intra-arterial BP (ABP) and based on cerebral perfusion pressure (CPP); and (iii) whether the MMPF method provides reproducible and reliable measure for noninvasive assessment of autoregulation. To achieve these aims, we analyzed data from existing databases including: (i) ABP and BFV of 12 healthy control, 10 hypertensive, and 10 stroke subjects during baseline resting conditions and during the Valsalva maneuver, and (ii) ABP, CPP, and BFV of 30 patients with traumatic brain injury (TBI) who were being paralyzed, sedated, and ventilated. We showed that autoregulation in healthy control subjects can be characterized by specific phase shifts between BP and BFV oscillations during the Valsalva maneuver, and the BP–BFV phase shifts were reduced in hypertensive and stroke subjects (P < 0.01), indicating impaired autoregulation. Similar results were found during baseline condition from spontaneous BP and BFV oscillations. The BP–BFV phase shifts obtained during baseline and during VM were highly correlated (R > 0.8, P < 0.0001), showing no statistical difference (paired-t test P > 0.47). In TBI patients there were strong

Comparison of force exerted on the sternum during a sneeze versus during low-, moderate-, and high-intensity bench press resistance exercise with and without the valsalva maneuver in healthy volunteers.

PubMed

Adams, Jenny; Schmid, Jack; Parker, Robert D; Coast, J Richard; Cheng, Dunlei; Killian, Aaron D; McCray, Stephanie; Strauss, Danielle; McLeroy Dejong, Sandra; Berbarie, Rafic

2014-03-15

Sternal precautions are intended to prevent complications after median sternotomy, but little data exist to support the consensus recommendations. To better characterize the forces on the sternum that can occur during everyday events, we conducted a prospective nonrandomized study of 41 healthy volunteers that evaluated the force exerted during bench press resistance exercise and while sneezing. A balloon-tipped esophageal catheter, inserted through the subject's nose and advanced into the thoracic cavity, was used to measure the intrathoracic pressure differential during the study activities. After the 1 repetition maximum (1-RM) was assessed, the subject performed the bench press at the following intensities, first with controlled breathing and then with the Valsalva maneuver: 40% of 1-RM (low), 70% of 1-RM (moderate), and 1-RM (high). Next, various nasal irritants were used to induce a sneeze. The forces on the sternum were calculated according to a cylindrical model, and a 2-tailed paired t test was used to compare the mean force exerted during a sneeze with the mean force exerted during each of the 6 bench press exercises. No statistically significant difference was found between the mean force from a sneeze (41.0 kg) and the mean total force exerted during moderate-intensity bench press exercise with breathing (41.4 kg). In conclusion, current guidelines and recommendations limit patient activity after a median sternotomy. Because these patients can repeatedly withstand a sneeze, our study indicates that they can withstand the forces from more strenuous activities than are currently allowed. Copyright © 2014 Elsevier Inc. All rights reserved.

Validity of the Water Hammer Formula for Determining Regional Aortic Pulse Wave Velocity: Comparison of One-Point and Two-Point (Foot-to-Foot) Measurements Using a Multisensor Catheter in Human

PubMed Central

2013-01-01

Background: Lack of high-fidelity simultaneous measurements of pressure and flow velocity in the aorta has impeded the direct validation of the water-hammer formula for estimating regional aortic pulse wave velocity (AO-PWV1) and has restricted the study of the change of beat-to-beat AO-PWV1 under varying physiological conditions in man. Methods: Aortic pulse wave velocity was derived using two methods in 15 normotensive subjects: 1) the conventional two-point (foot-to-foot) method (AO-PWV2) and 2) a one-point method (AO-PWV1) in which the pressure velocity-loop (PV-loop) was analyzed based on the water hammer formula using simultaneous measurements of flow velocity (Vm) and pressure (Pm) at the same site in the proximal aorta using a multisensor catheter. AO-PWV1 was calculated from the slope of the linear regression line between Pm and Vm where wave reflection (Pb) was at a minimum in early systole in the PV-loop using the water hammer formula, PWV1 = (Pm/Vm)/ρ, where ρ is the blood density. AO-PWV2 was calculated using the conventional two-point measurement method as the distance/traveling time of the wave between 2 sites for measuring P in the proximal aorta. Beat-to-beat alterations of AO-PWV1 in relationship to aortic pressure and linearity of the initial part of the PV-loop during a Valsalva maneuver were also assessed in one subject. Results: The initial part of the loop became steeper in association with the beat-to-beat increase in diastolic pressure in phase 4 during the Valsalva maneuver. The linearity of the initial part of the PV-loop was maintained consistently during the maneuver. Flow velocity vs. pressure in the proximal aorta was highly linear during early systole, with Pearson’s coefficients ranging from 0.9954 to 0.9998. The average values of AO-PWV1 and AO-PWV2 were 6.3 ± 1.2 and 6.7 ± 1.3 m/s, respectively. The regression line of AO-PWV1 on AO-PWV2 was y = 0.95x + 0.68 (r = 0.93, p <0.001). Conclusion: This study concluded that the

Vaginosacral colpopexy (VSC)--a new modification of the Mc Call operation using vaginosacral ligaments as autologous sliding grafts in posthysterectomy vault prolapse.

PubMed

Antovska, S V; Dimitrov, D G

2006-01-01

The effect of a new modification of the Mc Call operation, vaginosacral colpopexy (VSC) was evaluated in the group of 32 patients. Due to our bad experience with transabdominal lumbosacral colpopexy, we tried to find out another solution. VSC using the mobilized vaginosacral ligaments as sliding grafts (two sutures through the vaginosacral ligaments and posterior vaginal wall and the third suture through the uterosacral ligaments) for vault prolapse was performed in the group of 32 patients. Before operation, the median stage of prolapse was: stage III (range, 0-IV) for anterior site; stage II (range, 0-IV) for posterior site; stage I (range, 0-IV) of the apical segment, and stage III (range 0-IV) for the most severe segment of prolapse. The mean follow-up was 24.5 months (range 9-42 months). There were no intraoperative injuries of the bladder, ureter, rectum or small bowel. At the final follow-up, the mean stage of the prolapse was following: stage 0 (range, 0-III) for anterior site, posterior site and the most severe segment of prolapse; and stage 0 (range, 0-I) of the apical segment. The total vaginal length (tvl) increased significantly (p < 0.001) (Valsalva maneuver) (Vm) and (p < 0.001) (Pozzi maneuver) (Pm) from the preoperative mean value of 3.20 +/- 1.18 (Vm) and 2.70 +/- 0.92 (Pm) to (- 8.33 +/- 0.77) (Vm) and (-7.82 +/- 0.89) (Pm). All 8 patients with genuine stress incontinence, became continent. 3 of 4 patients with potential urinary incontinence required Marshal-Marchetti operation for persistent stress incontinence. VSC seems to be quick, safe and effective procedure for vault prolapse (Tab. 5, Fig. 8, Ref. 31).

Characterizing the active opening of the eustachian tube in a hypobaric/hyperbaric pressure chamber.

PubMed

Mikolajczak, Stefanie; Meyer, Moritz Friedo; Hahn, Moritz; Korthäuer, Christine; Jumah, Masen Dirk; Hüttenbrink, Karl-Bernd; Grosheva, Maria; Luers, Jan Christoffer; Beutner, Dirk

2015-01-01

Active and passive opening of the Eustachian tube (ET) enables direct aeration of the middle ear and a pressure balance between middle ear and the ambient pressure. The aim of this study was to characterize standard values for the opening pressure (ETOP), the opening frequency (ETOF), and the opening duration (ETOD) for active tubal openings (Valsalva maneuver, swallowing) in healthy participants. In a hypobaric/hyperbaric pressure chamber, 30 healthy participants (19 women, 11 men; mean age, 25.57 ± 3.33 years) were exposed to a standardized profile of compression and decompression. The pressure values were recorded via continuous impedance measurement during the Valsalva maneuver and swallowing. Based on the data, standard curves were identified and the ETOP, ETOD, and ETOF were determined. Recurring patterns of the pressure curve during active tube opening for the Valsalva maneuver and for active swallowing were characterized. The mean value for the Valsalva maneuver for ETOP was 41.21 ± 17.38 mbar; for the ETOD, it was 2.65 ± 1.87 seconds. In the active pressure compensation by swallowing, the mean value for the ETOP was 29.91 ± 13.07 mbar; and for the ETOD, it was 0.82 ± 0.53 seconds. Standard values for the opening pressure of the tube and the tube opening duration for active tubal openings (Valsalva maneuver, swallowing) were described, and typical curve gradients for healthy subjects could be shown. This is another step toward analyzing the function of the tube in compression and decompression.

Venous leakage treatment revisited: pelvic venoablation using aethoxysclerol under air block technique and Valsalva maneuver.

PubMed

Herwig, Ralf; Sansalone, Salvatore

2015-03-31

We evaluated the effectiveness of pelvic vein embolization with aethoxysclerol in aero-block technique for the treatment of impotence due to venous leakage in men using sildenafil for intercourse. The aim of the procedure was to reduce the use of sildenafil. A total of 96 patients with veno-occlusive dysfunction, severe enough for the need of PDE5 inhibitors for vaginal penetration, underwent pelvic venoablation with aethoxysclerol. The mean patient age was 53.5 years. Venous leaks were identified by Color Doppler Ultrasound after intracavernous alprostadil injection. Under local anesthesia a 20-gauge needle was inserted into the deep dorsal penile vein. The pelvic venogram was obtained through deep dorsal venography. Aethoxysclerol 3% as sclerosing agent was injected after air-block under Valsalva manoeuver. Success was defined as the ability to achieve vaginal insertion without the aid of any drugs, vasoactive injections, penile prosthesis, or vacuum device. Additionally, a pre- and post- therapy IIEF score and a digital overnight spontaneous erections protocol (OSEP) with the NEVA™-system was performed. At 3 month follow-up 77 out of 96 patients (80.21%) reported to have erections sufficient for vaginal insertion without the use of any drug or additional device. Four (4.17%) patients did not report any improvement. Follow up with color Doppler ultrasound revealed a new or persistent venous leakage in 8 (8.33%) of the patients. No serious complications occurred. Our new pelvic venoablation technique using aethoxysclerol in air-block technique was effective, minimally invasive, and cost-effective. All patients were able to perform sexual intercourse without the previously used dosage of PDE5 inhibitor. This new method may help in patients with contra-indications against PDE5 inhibitors, in patients who cannot afford the frequent usage of expensive oral medication or those who do not fully respond to PDE5-inhibitors.

Status and Roadmap of CernVM

NASA Astrophysics Data System (ADS)

Berzano, D.; Blomer, J.; Buncic, P.; Charalampidis, I.; Ganis, G.; Meusel, R.

2015-12-01

Cloud resources nowadays contribute an essential share of resources for computing in high-energy physics. Such resources can be either provided by private or public IaaS clouds (e.g. OpenStack, Amazon EC2, Google Compute Engine) or by volunteers computers (e.g. LHC@Home 2.0). In any case, experiments need to prepare a virtual machine image that provides the execution environment for the physics application at hand. The CernVM virtual machine since version 3 is a minimal and versatile virtual machine image capable of booting different operating systems. The virtual machine image is less than 20 megabyte in size. The actual operating system is delivered on demand by the CernVM File System. CernVM 3 has matured from a prototype to a production environment. It is used, for instance, to run LHC applications in the cloud, to tune event generators using a network of volunteer computers, and as a container for the historic Scientific Linux 5 and Scientific Linux 4 based software environments in the course of long-term data preservation efforts of the ALICE, CMS, and ALEPH experiments. We present experience and lessons learned from the use of CernVM at scale. We also provide an outlook on the upcoming developments. These developments include adding support for Scientific Linux 7, the use of container virtualization, such as provided by Docker, and the streamlining of virtual machine contextualization towards the cloud-init industry standard.

Coronary flow characteristics after a Bentall procedure with or without sinuses of Valsalva.

PubMed

de Paulis, Ruggero; Tomai, Fabrizio; Bertoldo, Fabio; Ghini, Anna S; Scaffa, Raffaele; Nardi, Paolo; Chiariello, Luigi

2004-07-01

The sinuses of Valsalva are known to contribute to the normal function of the aortic valve. Little is known about their role in promoting coronary artery blood flow. The aim of this study was to compare coronary artery flow characteristics among patients undergoing a Bentall operation by means of a conventional cylindrical Dacron conduit or with a new conduit with pseudosinuses of Valsalva or in patients retaining their natural sinuses of Valsalva after aortic valve and supracoronary ascending aorta replacement. One year after a Bentall procedure with a standard cylindrical Dacron conduit (7 patients, group A) or with the new conduit (7 patients, group B), or after aortic valve and ascending aortic replacement (control group, 7 patients, group C) coronary flow velocity reserve and diastolic to systolic time integral ratio at baseline and after maximal hyperemia (with 40 microg of adenosine) were assessed by using a 0.014-in. Doppler guidewire positioned in the middle portion of the left anterior descending coronary artery. All patients were in NYHA class I, sinus rhythm and free of coronary disease. Arterial blood pressures and heart rate were comparable among groups. Intracoronary Doppler measurements did not show any significant difference in coronary vascular reserve between the three groups (3.6+/-0.4 vs 3.1+/-0.7 vs 3.7+/-0.5, P = 0.2). A greater diastolic component at baseline was present in group B patients (5.5+/-1.9 vs 3.5+/-0.9 in group A and 3.7+/-0.9 in group C, P = 0.024). After maximal hyperemia the diastolic component increased slightly in group A patients (8%) while both in groups B and C significantly decreased (-15 and -20%, respectively) (P = 0.017). The presence of pseudosinuses of Valsalva does not influence coronary flow reserve. After maximal coronary vasodilation the increase in the systolic component of coronary flow is more evident in the presence of sinuses or pseudosinuses of Valsalva, thus suggesting that coronary flow pattern may be

Ultrasound imaging of the pelvic floor: changes in anatomy during and after first pregnancy.

PubMed

van Veelen, G A; Schweitzer, K J; van der Vaart, C H

2014-10-01

To describe changes in the absolute values of levator hiatal dimensions and in the contractility and distensibility of the levator hiatus during pelvic floor contraction and Valsalva maneuver, using three/four-dimensional (3D/4D) transperineal ultrasound in women during and after their first pregnancy. Two-hundred and eighty nulliparous pregnant women underwent ultrasound examination at 12 and 36 weeks' gestation and 6 months postpartum. Hiatal dimensions were measured at rest, on pelvic floor contraction and on Valsalva maneuver. The contractility and distensibility were determined by the difference between hiatal dimensions at rest and those on contraction or Valsalva, respectively. After exclusions, there were 231 datasets from women at rest, 199 for pelvic floor contraction and 230 for Valsalva maneuver. Data at 36 weeks' gestation and 6 months postpartum were compared with data at 12 weeks' gestation. At 36 weeks' gestation, the absolute values of hiatal dimensions and the contractility and distensibility of the levator hiatus were significantly increased compared with those at 12 weeks' gestation. Women who delivered vaginally showed a persistent significant increase in hiatal dimensions on Valsalva, whereas women who delivered by prelabor or first-stage Cesarean section showed no significant changes in hiatal dimensions on Valsalva. After both vaginal and Cesarean section delivery, there was a persistent increase in the distensibility of the hiatus during Valsalva compared with in early pregnancy. During first pregnancy, the absolute values of levator hiatal dimensions and the contractility and distensibility of the levator hiatus increase. Regardless of delivery mode, increased distensibility of the levator hiatus during Valsalva persists after childbirth. This increased pelvic floor distensibility may play a role in the development of pelvic floor dysfunction in later life. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Anomalous Origin of the Left Coronary Artery from the Right Sinus of Valsalva and Sever Mitral Stenosis

PubMed Central

Abdi, Ahmadnoor; Hashemi Fard, Omid

2011-01-01

Congenital coronary anomalies are presented in approximately1% of patient referred for cardiac catheterization. Among the congenital coronary anomalies, a separated anomalous origin of all the coronary arteries from the right sinus of valsalva is very uncommon. We report a rare occurance of simultaneous occurence of mitral stenosis with ectopic origin of left main stem coronary artery from right sinus of Valsalva. PMID:22577434

Diffusion bonding of IN 718 to VM 350 grade maraging steel

NASA Technical Reports Server (NTRS)

Crosby, S. R.; Biederman, R. R.; Reynolds, C. C.

1972-01-01

Diffusion bonding studies have been conducted on IN 718, VM 350 and the dissimilar alloy couple, IN 718 to maraging steel. The experimental processing parameters critical to obtaining consistently good diffusion bonds between IN 718 and VM 350 were determined. Interrelationships between temperature, pressure and surface preparation were explored for short bending intervals under vacuum conditions. Successful joining was achieved for a range of bonding cycle temperatures, pressures and surface preparations. The strength of the weaker parent material was used as a criterion for a successful tensile test of the heat treated bond. Studies of VM-350/VM-350 couples in the as-bonded condition showed a greater yielding and failure outside the bond region.

Synergistic effect of energy drinks and overweight/obesity on cardiac autonomic testing using the Valsalva maneuver in university students.

PubMed

Majeed, Farrukh; Yar, Talay; Alsunni, Ahmed; Alhawaj, Ali Fouad; AlRahim, Ahmed; Alzaki, Muneer

2017-01-01

Obesity and caffeine consumption may lead to autonomic disturbances that can result in a wide range of cardiovascular disorders. To determine autonomic disturbances produced by the synergistic effects of overweight or obesity (OW/OB) and energy drinks. Cross-sectional, analytical. Physiology department at a university in Saudi Arabia. University students, 18-22 years of age, of normal weight (NW) and OW/OB were recruited by convenience sampling. Autonomic testing by the Valsalva ratio (VR) along with systolic and diastolic blood pressure, pulse pressure, and mean arterial blood pressure were measured at baseline (0 minute) and 60 minutes after energy drink consumption. Autonomic disturbance, hemodynamic changes. In 50 (27 males and 23 females) subjects, 21 NW and 29 OW/OB, a significant decrease in VR was observed in OW/OB subjects and in NW and OW/OB females at 60 minutes after energy drink consumption. Values of systolic and diastolic blood pressure, pulse pressure and mean arterial blood pressure were also significantly higher in OW/OB and in females as compared to NW and males. BMI was negatively correlated with VR and diastolic blood pressure at 60 minutes. Obesity and energy drinks alter autonomic functions. In some individuals, OW/OB may augment these effects. Due to time and resource restraints, only the acute effects of energy drinks were examined.

Maneuver Automation Software

NASA Technical Reports Server (NTRS)

Uffelman, Hal; Goodson, Troy; Pellegrin, Michael; Stavert, Lynn; Burk, Thomas; Beach, David; Signorelli, Joel; Jones, Jeremy; Hahn, Yungsun; Attiyah, Ahlam;

A single-center randomized controlled trial observing the safety and efficacy of modified step-up graded Valsalva manoeuver in patients with vasovagal syncope.

PubMed

He, Li; Wang, Lan; Li, Lun; Liu, Xiaoyan; Yu, Yijun; Zeng, Xiaoyun; Li, Huanhuan; Gu, Ye

2018-01-01

Non-pharmacological therapies, especially the physical maneuvers, are viewed as important and promising strategies for reducing syncope recurrences in vasovagal syncope (VVS) patients. We observed the efficacy of a modified Valsalva maneuver (MVM) in VVS patients. 72 VVS patients with syncope history and positive head-up tilt table testing (HUTT) results were randomly divided into conventional treatment group (NVM group, n = 36) and conventional treatment plus standard MVM for 30 days group (MVM group, n = 36). Incidence of recurrent syncope after 12 months (6.5% vs. 41.2%, P<0.01) and rate of positive HUTT after 30 days (9.7% vs.79.4%, P<0.01) were significantly lower in MVM group than in NVM group. HRV results showed that low frequency (LF), LF/ high frequency (HF), standard deviation of NN intervals (SDNN) and standard deviation of all 5-min average NN intervals (SDANN) values were significantly lower in the NVM and MVM groups than in the control group at baseline. After 30 days treatment, LF, LF/HF, SDNN, SDANN values were significantly higher compared to baseline in MVM group. Results of Cox proportional hazard model showed that higher SDNN and SDANN values at 30 days after intervention were protective factors, while positive HUTT at 30 days after intervention was risk factor for recurrent syncope. Our results indicate that 30 days MVM intervention could effectively reduce the incidence of recurrent syncope up to 12 months in VVS patients, possibly through improving sympathetic function of VVS patients.

Effect of Valsalva's manoeuvre and hyoscinbutylbromide on the pressure gradient across the wall of oesophageal varices.

PubMed Central

Hosking, S W; Robinson, P; Johnson, A G

1987-01-01

To assess whether Valsalva's manoeuvre might cause variceal bleeding, 22 patients with oesophageal varices were studied. In 12 patients who received no previous treatment to their varices the median pressure gradient across the varix wall at rest was 19 (6-36) mmHg, and in 10 patients whose varices were thrombosed at their distal end the median pressure gradient in the proximal patent varix was 8 (1-6) mmHg. In untreated patients groups, the pressure gradient rose by 6-12 mmHg during Valsalva's manoeuvre in four patients, fell by 4-11 mmHg in five patients and was virtually unchanged in the remainder. These changes seem unlikely to cause variceal bleeding. Patients who repeated Valsalva's manoeuvre showed similar changes on each occasion. Six patients in the untreated group also received hyoscinbutylbromide 20 mg iv. No change was seen in the pressure gradient in five patients, suggesting that it is of little value in preventing variceal bleeding. PMID:3500098

Single coronary artery originating from the right sinus Valsalva and ability to work.

PubMed

De Rosa, Roberto; Ratti, Gennaro; Gerardi, Donato; Tedeschi, Carlo; Lamberti, Monica

2015-01-01

We present a case of a 56-year-old male electrician who was admitted to the hospital with atrial fibrillation, atypical chest pain and dyspnea. He gave a history that on the morning he had working for almost 4 hours carrying out various activities with considerable physical effort. After cardioversion, conventional coronary angiography revealed a suspect of single coronary vessel (SCA) arising from the right sinus of Valsalva. The patient underwent multislice computed tomography that showed a SCA arising from the right sinus Valsalva and dividing in Right Coronary Artery (RCA) and Left Main coronary artery (LM). The finding of posterior course of the LM without atherosclerotic has proved crucial for the expression of an opinion of working capacity even with limitation.

Toxicity and medical countermeasure studies on the organophosphorus nerve agents VM and VX.

PubMed

Rice, Helen; Dalton, Christopher H; Price, Matthew E; Graham, Stuart J; Green, A Christopher; Jenner, John; Groombridge, Helen J; Timperley, Christopher M

2015-04-08

To support the effort to eliminate the Syrian Arab Republic chemical weapons stockpile safely, there was a requirement to provide scientific advice based on experimentally derived information on both toxicity and medical countermeasures (MedCM) in the event of exposure to VM, VX or VM-VX mixtures. Complementary in vitro and in vivo studies were undertaken to inform that advice. The penetration rate of neat VM was not significantly different from that of neat VX, through either guinea pig or pig skin in vitro . The presence of VX did not affect the penetration rate of VM in mixtures of various proportions. A lethal dose of VM was approximately twice that of VX in guinea pigs poisoned via the percutaneous route. There was no interaction in mixed agent solutions which altered the in vivo toxicity of the agents. Percutaneous poisoning by VM responded to treatment with standard MedCM, although complete protection was not achieved.

Detection of patent foramen ovale by contrast transesophageal echocardiography.

PubMed

Chen, W J; Kuan, P; Lien, W P; Lin, F Y

1992-06-01

A series of 32 patients undergoing cardiac catheterization and/or operation to document the presence of patent foramen ovale (PFO) were studied. All were examined by contrast transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) during normal breathing and the Valsalva maneuver. A right-to-left shunt at the atrial level was visualized by contrast TEE in 14 patients during normal breathing and in 20 patients during the Valsalva maneuver. In comparison, contrast TTE revealed this shunt in only eight patients during normal breathing and in 12 patients during the Valsalva maneuver. All of the foramina proved to be patent by contrast TTE were also found by contrast TEE. All but one (19 of 20) patients, shown to have PFO by contrast TEE, could be confirmed at cardiac catheterization and/or operation. Using cardiac catheterization and/or operation as a gold standard, contrast TEE appears to be a more sensitive (100 percent vs 63 percent, p less than 0.005) and accurate (97 percent vs 78 percent, p less than 0.05) method than contrast TTE in the detection of PFO.

Influence of microgravity on astronauts' sympathetic and vagal responses to Valsalva's manoeuvre

NASA Technical Reports Server (NTRS)

Cox, James F.; Tahvanainen, Kari U O.; Kuusela, Tom A.; Levine, Benjamin D.; Cooke, William H.; Mano, Tadaaki; Iwase, Satoshi; Saito, Mitsuru; Sugiyama, Yoshiki; Ertl, Andrew C.;

Empirical Evaluation of Conservative and Optimistic Discrete Event Execution on Cloud and VM Platforms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoginath, Srikanth B; Perumalla, Kalyan S

2013-01-01

Virtual machine (VM) technologies, especially those offered via Cloud platforms, present new dimensions with respect to performance and cost in executing parallel discrete event simulation (PDES) applications. Due to the introduction of overall cost as a metric, the choice of the highest-end computing configuration is no longer the most economical one. Moreover, runtime dynamics unique to VM platforms introduce new performance characteristics, and the variety of possible VM configurations give rise to a range of choices for hosting a PDES run. Here, an empirical study of these issues is undertaken to guide an understanding of the dynamics, trends and trade-offsmore » in executing PDES on VM/Cloud platforms. Performance results and cost measures are obtained from actual execution of a range of scenarios in two PDES benchmark applications on the Amazon Cloud offerings and on a high-end VM host machine. The data reveals interesting insights into the new VM-PDES dynamics that come into play and also leads to counter-intuitive guidelines with respect to choosing the best and second-best configurations when overall cost of execution is considered. In particular, it is found that choosing the highest-end VM configuration guarantees neither the best runtime nor the least cost. Interestingly, choosing a (suitably scaled) low-end VM configuration provides the least overall cost without adversely affecting the total runtime.« less

[Transesophageal echocardiography diagnosis of ruptured aneurysm of the Valsalva sinus associated with aneurysm of the interatrial septum].

PubMed

Imperadore, Ferdinando; Ferro, Aldo; Graffigna, Angelo; Vergara, Giuseppe

2002-01-01

Aneurysms of the sinus of Valsalva are uncommon heart defects that often remain undetected unless rupture occurs. They have been reported in association with other cardiac anomalies. The present case report deals with a 51-year-old man who was referred to our division with a diagnosis of recent-onset progressive heart failure. Echocardiographic evaluation, both transthoracic and transesophageal, disclosed rupture of an aneurysm of the non-coronary sinus of Valsalva into the right atrium. This anomaly was associated with an aneurysm of the atrial septum.

Scalp-recorded slow EEG responses generated in response to hemodynamic changes in the human brain.

PubMed

Vanhatalo, S; Tallgren, P; Becker, C; Holmes, M D; Miller, J W; Kaila, K; Voipio, J

2003-09-01

To study whether hemodynamic changes in human brain generate scalp-EEG responses. Direct current EEG (DC-EEG) was recorded from 12 subjects during 5 non-invasive manipulations that affect intracranial hemodynamics by different mechanisms: bilateral jugular vein compression (JVC), head-up tilt (HUT), head-down tilt (HDT), Valsalva maneuver (VM), and Mueller maneuver (MM). DC shifts were compared to changes in cerebral blood volume (CBV) measured by near-infrared spectroscopy (NIRS). DC shifts were observed during all manipulations with highest amplitudes (up to 250 microV) at the midline electrodes, and the most pronounced changes (up to 15 microV/cm) in the DC voltage gradient around vertex. In spite of inter-individual variation in both amplitude and polarity, the DC shifts were consistent and reproducible for each subject and they showed a clear temporal correlation with changes in CBV. Our results indicate that hemodynamic changes in human brain are associated with marked DC shifts that cannot be accounted for by intracortical neuronal or glial currents. Instead, the data are consistent with a non-neuronal generator mechanism that is associated with the blood-brain barrier. These findings have direct implications for mechanistic interpretation of slow EEG responses in various experimental paradigms.

A single-center randomized controlled trial observing the safety and efficacy of modified step-up graded Valsalva manoeuver in patients with vasovagal syncope

PubMed Central

Liu, Xiaoyan; Yu, Yijun; Zeng, Xiaoyun; Li, Huanhuan

2018-01-01

Non-pharmacological therapies, especially the physical maneuvers, are viewed as important and promising strategies for reducing syncope recurrences in vasovagal syncope (VVS) patients. We observed the efficacy of a modified Valsalva maneuver (MVM) in VVS patients. 72 VVS patients with syncope history and positive head-up tilt table testing (HUTT) results were randomly divided into conventional treatment group (NVM group, n = 36) and conventional treatment plus standard MVM for 30 days group (MVM group, n = 36). Incidence of recurrent syncope after 12 months (6.5% vs. 41.2%, P<0.01) and rate of positive HUTT after 30 days (9.7% vs.79.4%, P<0.01) were significantly lower in MVM group than in NVM group. HRV results showed that low frequency (LF), LF/ high frequency (HF), standard deviation of NN intervals (SDNN) and standard deviation of all 5-min average NN intervals (SDANN) values were significantly lower in the NVM and MVM groups than in the control group at baseline. After 30 days treatment, LF, LF/HF, SDNN, SDANN values were significantly higher compared to baseline in MVM group. Results of Cox proportional hazard model showed that higher SDNN and SDANN values at 30 days after intervention were protective factors, while positive HUTT at 30 days after intervention was risk factor for recurrent syncope. Our results indicate that 30 days MVM intervention could effectively reduce the incidence of recurrent syncope up to 12 months in VVS patients, possibly through improving sympathetic function of VVS patients. PMID:29381726

Toxicity and medical countermeasure studies on the organophosphorus nerve agents VM and VX

PubMed Central

Rice, Helen; Dalton, Christopher H.; Price, Matthew E.; Graham, Stuart J.; Green, A. Christopher; Jenner, John; Groombridge, Helen J.; Timperley, Christopher M.

2015-01-01

To support the effort to eliminate the Syrian Arab Republic chemical weapons stockpile safely, there was a requirement to provide scientific advice based on experimentally derived information on both toxicity and medical countermeasures (MedCM) in the event of exposure to VM, VX or VM–VX mixtures. Complementary in vitro and in vivo studies were undertaken to inform that advice. The penetration rate of neat VM was not significantly different from that of neat VX, through either guinea pig or pig skin in vitro. The presence of VX did not affect the penetration rate of VM in mixtures of various proportions. A lethal dose of VM was approximately twice that of VX in guinea pigs poisoned via the percutaneous route. There was no interaction in mixed agent solutions which altered the in vivo toxicity of the agents. Percutaneous poisoning by VM responded to treatment with standard MedCM, although complete protection was not achieved. PMID:27547080

A VM-shared desktop virtualization system based on OpenStack

NASA Astrophysics Data System (ADS)

Liu, Xi; Zhu, Mingfa; Xiao, Limin; Jiang, Yuanjie

2018-04-01

With the increasing popularity of cloud computing, desktop virtualization is rising in recent years as a branch of virtualization technology. However, existing desktop virtualization systems are mostly designed as a one-to-one mode, which one VM can only be accessed by one user. Meanwhile, previous desktop virtualization systems perform weakly in terms of response time and cost saving. This paper proposes a novel VM-Shared desktop virtualization system based on OpenStack platform. The paper modified the connecting process and the display data transmission process of the remote display protocol SPICE to support VM-Shared function. On the other hand, we propose a server-push display mode to improve user interactive experience. The experimental results show that our system performs well in response time and achieves a low CPU consumption.

Security model for VM in cloud

NASA Astrophysics Data System (ADS)

Kanaparti, Venkataramana; Naveen K., R.; Rajani, S.; Padmvathamma, M.; Anitha, C.

2013-03-01

Cloud computing is a new approach emerged to meet ever-increasing demand for computing resources and to reduce operational costs and Capital Expenditure for IT services. As this new way of computation allows data and applications to be stored away from own corporate server, it brings more issues in security such as virtualization security, distributed computing, application security, identity management, access control and authentication. Even though Virtualization forms the basis for cloud computing it poses many threats in securing cloud. As most of Security threats lies at Virtualization layer in cloud we proposed this new Security Model for Virtual Machine in Cloud (SMVC) in which every process is authenticated by Trusted-Agent (TA) in Hypervisor as well as in VM. Our proposed model is designed to with-stand attacks by unauthorized process that pose threat to applications related to Data Mining, OLAP systems, Image processing which requires huge resources in cloud deployed on one or more VM's.

Jugular veins in transient global amnesia: innocent bystanders.

PubMed

Baracchini, Claudio; Tonello, Simone; Farina, Filippo; Viaro, Federica; Atzori, Matteo; Ballotta, Enzo; Manara, Renzo

2012-09-01

Transient global amnesia (TGA) has been associated with an increased prevalence of internal jugular valve insufficiency and many patients report Valsalva-associated maneuvers before TGA onset. These findings have led to the assumption of hemodynamic alterations in intracranial veins inducing focal hippocampal ischemia. We investigated this hypothesis in patients with TGA and control subjects. Seventy-five patients with TGA and 75 age- and sex-matched healthy subjects were enrolled into a cross-sectional study. Extracranial and transcranial high-resolution venous echo-color-Doppler sonography was performed blindly in all patients and control subjects. Blood flow direction and velocities were recorded at the internal jugular veins, basal veins of Rosenthal, and vein of Galen, both at rest and during Valsalva-associated maneuvers. Mean age of patients with TGA was 60.3±8.0 years (median, 60 years; range, 44-78 years); 44 (59%) were female (female/male ratio: 1.42). Internal jugular valve insufficiency (left, right, or bilateral) was found to be more frequent in patients with TGA than in control subjects: 53 (70.7%) versus 22 (29.3%; P<0.05). Blood flow velocities in the deep cerebral veins of patients with TGA did not differ from control subjects both at rest and during Valsalva-associated maneuvers. Intracranial venous reflux was neither observed in patients with TGA nor in control subjects despite unilateral or bilateral internal jugular valve insufficiency during prolonged and maximal Valsalva-associated maneuvers. This study, although confirming the association between TGA and internal jugular valve insufficiency, challenges the hypothesis that cerebral venous congestion plays a significant role in the pathogenesis of TGA.

Echocolor Doppler morpho-functional study of the jugulo-subclavian confluence in chronic cerebro-spinal venous insufficiency and multiple sclerosis patients.

PubMed

Mandolesi, Sandro; d'Alessandro, Aldo; Desogus, Antonello Ignazio; Ciccone, Marco Matteo; Zito, Annapaola; Stammegna, Immacolata; Niglio, Tarcisio; Orsini, Augusto; Mandolesi, Dimitri; d'Alessandro, Alessandro; Revelli, Luca

2017-01-01

The aim of this work is to measure the mean diameter of the confluence jugulo- subclavian, the impact of different types of jugular confluences and the correlation between the types of confluences and the Valsalva maneuver (jugular reflux) in subjects with Chronic Cerebro-Spinal Venous Insufficiency (CCSVI) and Multiple Sclerosis. We investigated by Echo-Color-Doppler (ECD) 103 subjects (67 F 36M) of mean age 45 ± 12 years (a minimum of 22 to a maximum of 79 years, with a median of 44 and a modal value 42 years), mean EDSS of 4.7 and average disease duration of 12 years. The 103 right jugular veins investigated had an average diameter of 8.4 ± 2.4 mm (minimum 4.0, maximum 14.9 mm; median 7.9; modal value 7.6 mm). Three form types were found: 56 cylindrical, 29 conical and 18 funnel. Valsalva maneuver was positive in 30 patients. The 103 left jugular investigated had an average diameter of 8.9 ± 2.4 mm (minimum 2.8, maximum 14.4 mm; median of 8.8; modal value 8.7 mm). The form types were found: 42 cylindrical, 45 conical and 16 funnel. Valsalva maneuver was positive in 30 patients. The mean diameter of the jugular veins was 8.7 mm. Internal jugular veins with cylindrical morphology have a diameter smaller than other forms; this difference is statistically significant. The different morphology of the jugular vein confluence does not increase the possibility of a reflux because the positive Valsalva maneuvers are not statistically significant when compared to the various types. CCSVI, EchoColorDoppler Map, Jugulo-Subclavian Confluence Diameter.

Novel designed VmCT1 analogs with increased antimicrobial activity.

PubMed

Pedron, Cibele Nicolaski; Torres, Marcelo Der Torossian; Lima, Julia Aparecida da Silva; Silva, Pedro Ismael; Silva, Fernanda Dias; Oliveira, Vani Xavier

2017-01-27

Antimicrobial peptides are biologically active molecules produced by a wide range of organisms as an essential component of the innate immune response. They have recently attracted great interest, since they have antimicrobial activity against a broad spectrum of microorganisms. VmCT1 is a cationic peptide from the venom of Vaejovis mexicanus smithi scorpions, which presents antibacterial activity and tends to helical structures. Its analogs were synthesized, characterized and the conformational studies were performed by circular dichroism. The peptides were designed to verify if the single and double substitutions proposed at the hydrophilic and hydrophobic portions of the amphipathic structure would alter antimicrobial activity against Gram-negative and Gram-positive bacteria, yeast and filamentous fungus, besides the hemolytic activity in human erythrocytes. Total charge of the peptides were modified from +2 to +3 by the introduction of a Lysine residue in the hydrophilic face of the amphiphilic helical structure leading to enhanced antimicrobial activity. [K] 11 -VmCT1-NH 2 presented the lower MIC value against the microorganisms (from 0.39 to 6.25 μmol L -1 ), however it showed higher hemolytic activity. The other Lysine-substituted analogs presented also lower MIC values ranging from 0.39 to 25 μmol L -1 for the microorganisms assessed. The circular dichroism spectra analyses suggest that the Lysine-substituted analogs tend to adopt helical structures in trifluoroethanol solution and vesicles (f H : 0.43-1), however they were coiled in water. Alanine substitution by a Glutamic acid residue in the hydrophilic face promotes the increase of polar angle in [E] 4 -VmCT1-NH 2 analog, which was important to led lower hemolytic activity (MHC value = 25 μmol L -1 ). [W] 9 -VmCT1-NH 2 and [E] 4 [W] 9 -VmCT1-NH 2 were designed to favors hydrophobic interactions by the introduction of Tryptophan residue. [W] 9 -VmCT1-NH 2 presented MIC values lower or

Remote operation of an orbital maneuvering vehicle in simulated docking maneuvers

NASA Technical Reports Server (NTRS)

Brody, Adam R.

1990-01-01

Simulated docking maneuvers were performed to assess the effect of initial velocity on docking failure rate, mission duration, and delta v (fuel consumption). Subjects performed simulated docking maneuvers of an orbital maneuvering vehicle (OMV) to a space station. The effect of the removal of the range and rate displays (simulating a ranging instrumentation failure) was also examined. Naive subjects were capable of achieving a high success rate in performing simulated docking maneuvers without extensive training. Failure rate was a function of individual differences; there was no treatment effect on failure rate. The amount of time subjects reserved for final approach increased with starting velocity. Piloting of docking maneuvers was not significantly affected in any way by the removal of range and rate displays. Radial impulse was significant both by subject and by treatment. NASA's 0.1 percent rule, dictating an approach rate no greater than 0.1 percent of the range, is seen to be overly conservative for nominal docking missions.

Alterations in left ventricular volumes induced by Valsalva manoeuvre

NASA Technical Reports Server (NTRS)

Brooker, J. Z.; Alderman, E. L.; Harrison, D. C.

1974-01-01

Five patients were studied with left ventriculography during different phases of the Valsalva manoeuvre. Small doses of contrast medium allowed adequate repetitive visualization of the left ventricle for volume calculation. During strain phase, the volume of the left ventricle decreased by nearly 50 per cent in each case, and stroke volume and cardiac output also dropped strikingly. Release of straining was attended by a sharp rebound of left ventricular volume to control levels, with a transient surge of increased cardiac output 42 per cent above that of the resting state.

Respiratory-Induced Haemodynamic Changes: A Contributing Factor to IVC Filter Penetration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laborda, Alicia, E-mail: alaborda@unizar.es; Kuo, William T., E-mail: wkuo@stanford.edu; Ioakeim, Ignatios, E-mail: ignacio.ioakim@hotmail.es

2015-10-15

PurposeThe purpose of the study is to evaluate the influence of respiratory-induced vena caval hemodynamic changes on filter migration/penetration.Materials and MethodsAfter placement of either a Gunther Tulip or Celect IVC filter, 101 consecutive patients scheduled for filter retrieval were prospectively enrolled in this study. Pre-retrieval CT scans were used to assess filter complications and to calculate cross-sectional area in three locations: at level of filter strut fixation, 3 cm above and 3 cm below. A 3D finite element simulation was constructed on these data and direct IVC pressure was recorded during filter retrieval. Cross-sectional areas and pressures of the vena cava weremore » measured during neutral breathing and in Valsalva maneuver and identified filter complications were recorded. A statistical analysis of these variables was then performed.ResultsDuring Valsalva maneuvers, a 60 % decrease of the IVC cross-sectional area and a fivefold increase in the IVC pressure were identified (p < 0.001). There was a statistically significant difference in the reduction of the cross-sectional area at the filter strut level (p < 0.001) in patient with filter penetration. Difficulty in filter retrieval was higher in penetrated or tilted filters (p < 0.001; p = 0.005). 3D computational models showed significant IVC deformation around the filter during Valsalva maneuver.ConclusionCaval morphology and hemodynamics are clearly affected by Valsalva maneuvers. A physiological reduction of IVC cross-sectional area is associated with higher risk of filter penetration, despite short dwell times. Physiologic data should be used to improve future filter designs to remain safely implanted over longer dwell times.« less

Open label study to assess the safety of VM202 in subjects with amyotrophic lateral sclerosis.

PubMed

Sufit, Robert L; Ajroud-Driss, Senda; Casey, Patricia; Kessler, John A

2017-05-01

To assess safety and define efficacy measures of hepatocyte growth factor (HGF) DNA plasmid, VM202, administered by intramuscular injections in patients with amyotrophic lateral sclerosis (ALS). Eighteen participants were treated with VM202 administered in divided doses by injections alternating between the upper and lower limbs on d 0, 7, 14, and 21. Subjects were followed for nine months to evaluate possible adverse events. Functional outcome was assessed using the ALS Functional Rating Scale-Revised (ALSFRS-R) as well as by serially measuring muscle strength, muscle circumference, and forced vital capacity. Seventeen of 18 participants completed the study. All participants tolerated 64 mg of VM202 well with no serious adverse events (SAE) related to the drug. Twelve participants reported 26 mild or moderate injection site reactions. Three participants experienced five SAEs unrelated to VM202. One subject died from respiratory insufficiency secondary to ALS progression. Multiple intramuscular injection of VM202 into the limbs appears safe in ALS subjects. Future trials with retreatment after three months will determine whether VM202 treatment alters the long-term course of ALS.

The Effect of Warm Compress Bistage Intervention on the Rate of Episiotomy, Perineal Trauma, and Postpartum Pain Intensity in Primiparous Women with Delayed Valsalva Maneuver Referring to the Selected Hospitals of Shiraz University of Medical Sciences in 2012-2013.

PubMed

Akbarzadeh, Marzieh; Vaziri, Faride; Farahmand, Mahnaz; Masoudi, Zahra; Amooee, Sedigheh; Zare, Najaf

2016-02-01

Genital trauma during vaginal delivery may result from episiotomy, spontaneous perineal tears (perineum, vagina), or both. In 2012, this study aimed to investigate the effect of warm compress bistage intervention on the rate of episiotomy, perineal trauma, and postpartum pain intensity in the primiparous woman with delayed Valsalva maneuver. In this randomized clinical trial, which was performed in hospitals in Shiraz, Iran, in 2012-2013, 150 women were randomly divided into 2 groups: 1 intervention and 1 control. The intervention group received warm compress bistage intervention at 7-cm and 10-cm dilatation and zero position during the first and second stages of labor for 15 to 20 minutes, whereas the control group received the hospitals' routine care. After delivery, the prevalence of episiotomy; intact perineum; location, degree, and length of rupture; and postpartum pain intensity were assessed in the 2 groups. Following that, the data were analyzed with SPSS statistical software (version 16) using χ test, t test, and odds ratio. The results revealed a significant difference between the intervention and control groups regarding the frequency of intact perinea (27% vs 6.7%) and the frequency of episiotomy (45% vs 90.70%). In addition, the frequency of the location of rupture (P = .019), mean length of episiotomy incision (P = .02), and mean intensity of pain the day after delivery (P < .001) were significantly lower in the intervention group compared with the control group. However, the rate of ruptures was higher in the intervention group. Warm compress bistage intervention was effective in reducing episiotomies and the mean length of episiotomy incision, reducing pain after delivery, and increasing the rate of intact perinea. However, the rate of ruptures slightly increased in the intervention group compared with the control group.

Progress on a novel VM-type pulse tube cryocooler for 4 K

NASA Astrophysics Data System (ADS)

Pan, Changzhao; Wang, Jue; Luo, Kaiqi; Wang, Junjie; Zhou, Yuan

2017-12-01

VM type pulse tube cryocooler is a new type pulse tube cryocooler driven by the thermal-compressor. This paper presented the recent experimental results on a novel single-stage VM type pulse tube cryocooler with multi-bypass. The low temperature double-inlet, orifice and gas reservoir, and multi-bypass were used as phase shifters. With the optimal operating frequency of 1.6 Hz and optimal average pressure of 1.4 MPa, a no-load temperature of 4.9 K has been obtained and 30 mW@5.6 K cooling power has been achieved. It was the first time for the single-stage VM-PTC obtaining liquid helium temperature reported so far. Moreover, it was also the first time for the multi-bypass being used in the low-frequency Stirling type pulse tube cryocooler.

A novel coupled VM-PT cryocooler operating at liquid helium temperature

NASA Astrophysics Data System (ADS)

Pan, Changzhao; Zhang, Tong; Zhou, Yuan; Wang, Junjie

2016-07-01

This paper presents experimental results on a novel two-stage gas-coupled VM-PT cryocooler, which is a one-stage VM cooler coupled a pulse tube cooler. In order to reach temperatures below the critical point of helium-4, a one-stage coaxial pulse tube cryocooler was gas-coupled on the cold end of the former VM cryocooler. The low temperature inertance tube and room temperature gas reservoir were used as phase shifters. The influence of room temperature double-inlet was first investigated, and the results showed that it added excessive heat loss. Then the inertance tube, regenerator and the length of the pulse tube were researched experimentally. Especially, the DC flow, whose function is similar to the double-orifice, was experimentally studied, and shown to contribute about 0.2 K for the no-load temperature. The minimum no-load temperature of 4.4 K was obtained with a pressure ratio near 1.5, working frequency of 2.2 Hz, and average pressure of 1.73 MPa.

Cassini's Maneuver Automation Software (MAS) Process: How to Successfully Command 200 Navigation Maneuvers

NASA Technical Reports Server (NTRS)

Yang, Genevie Velarde; Mohr, David; Kirby, Charles E.

2008-01-01

To keep Cassini on its complex trajectory, more than 200 orbit trim maneuvers (OTMs) have been planned from July 2004 to July 2010. With only a few days between many of these OTMs, the operations process of planning and executing the necessary commands had to be automated. The resulting Maneuver Automation Software (MAS) process minimizes the workforce required for, and maximizes the efficiency of, the maneuver design and uplink activities. The MAS process is a well-organized and logically constructed interface between Cassini's Navigation (NAV), Spacecraft Operations (SCO), and Ground Software teams. Upon delivery of an orbit determination (OD) from NAV, the MAS process can generate a maneuver design and all related uplink and verification products within 30 minutes. To date, all 112 OTMs executed by the Cassini spacecraft have been successful. MAS was even used to successfully design and execute a maneuver while the spacecraft was in safe mode.

14 CFR 25.1507 - Maneuvering speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c). ...

14 CFR 25.1507 - Maneuvering speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c). ...

The Conserved Spore Coat Protein SpoVM Is Largely Dispensable in Clostridium difficile Spore Formation.

PubMed

Ribis, John W; Ravichandran, Priyanka; Putnam, Emily E; Pishdadian, Keyan; Shen, Aimee

2017-01-01

The spore-forming bacterial pathogen Clostridium difficile is a leading cause of health care-associated infections in the United States. In order for this obligate anaerobe to transmit infection, it must form metabolically dormant spores prior to exiting the host. A key step during this process is the assembly of a protective, multilayered proteinaceous coat around the spore. Coat assembly depends on coat morphogenetic proteins recruiting distinct subsets of coat proteins to the developing spore. While 10 coat morphogenetic proteins have been identified in Bacillus subtilis , only two of these morphogenetic proteins have homologs in the Clostridia : SpoIVA and SpoVM. C. difficile SpoIVA is critical for proper coat assembly and functional spore formation, but the requirement for SpoVM during this process was unknown. Here, we show that SpoVM is largely dispensable for C. difficile spore formation, in contrast with B. subtilis . Loss of C. difficile SpoVM resulted in modest decreases (~3-fold) in heat- and chloroform-resistant spore formation, while morphological defects such as coat detachment from the forespore and abnormal cortex thickness were observed in ~30% of spoVM mutant cells. Biochemical analyses revealed that C. difficile SpoIVA and SpoVM directly interact, similarly to their B. subtilis counterparts. However, in contrast with B. subtilis , C. difficile SpoVM was not essential for SpoIVA to encase the forespore. Since C. difficile coat morphogenesis requires SpoIVA-interacting protein L (SipL), which is conserved exclusively in the Clostridia , but not the more broadly conserved SpoVM, our results reveal another key difference between C. difficile and B. subtilis spore assembly pathways. IMPORTANCE The spore-forming obligate anaerobe Clostridium difficile is the leading cause of antibiotic-associated diarrheal disease in the United States. When C. difficile spores are ingested by susceptible individuals, they germinate within the gut and

Cassini-Huygens maneuver automation for navigation

NASA Technical Reports Server (NTRS)

Goodson, Troy; Attiyah, Amy; Buffington, Brent; Hahn, Yungsun; Pojman, Joan; Stavert, Bob; Strange, Nathan; Stumpf, Paul; Wagner, Sean; Wolff, Peter;

Multi-Maneuver Clohessy-Wiltshire Targeting

NASA Technical Reports Server (NTRS)

Dannemiller, David P.

2011-01-01

Orbital rendezvous involves execution of a sequence of maneuvers by a chaser vehicle to bring the chaser to a desired state relative to a target vehicle while meeting intermediate and final relative constraints. Intermediate and final relative constraints are necessary to meet a multitude of requirements such as to control approach direction, ensure relative position is adequate for operation of space-to-space communication systems and relative sensors, provide fail-safe trajectory features, and provide contingency hold points. The effect of maneuvers on constraints is often coupled, so the maneuvers must be solved for as a set. For example, maneuvers that affect orbital energy change both the chaser's height and downrange position relative to the target vehicle. Rendezvous designers use experience and rules-of-thumb to design a sequence of maneuvers and constraints. A non-iterative method is presented for targeting a rendezvous scenario that includes a sequence of maneuvers and relative constraints. This method is referred to as Multi-Maneuver Clohessy-Wiltshire Targeting (MM_CW_TGT). When a single maneuver is targeted to a single relative position, the classic CW targeting solution is obtained. The MM_CW_TGT method involves manipulation of the CW state transition matrix to form a linear system. As a starting point for forming the algorithm, the effects of a series of impulsive maneuvers on the state are derived. Simple and moderately complex examples are used to demonstrate the pattern of the resulting linear system. The general form of the pattern results in an algorithm for formation of the linear system. The resulting linear system relates the effect of maneuver components and initial conditions on relative constraints specified by the rendezvous designer. Solution of the linear system includes the straight-forward inverse of a square matrix. Inversion of the square matrix is assured if the designer poses a controllable scenario - a scenario where the the

Further development and characterization of VM-103, a NASA wrought cobalt base alloy

NASA Technical Reports Server (NTRS)

Harlow, R. A.; Ritchie, E. E.

1972-01-01

The data obtained during this and previous programs indicate that the VM-103 has useful strength at temperatures as high 2200 F (1204 C), and can be considered as an alternate for other wrought superalloys such as L-605. The addition of 10 percent nickel to the standard composition improves both the hot and cold fabricability, ductility, impact strength, and metallurgical stability, while it only slightly reduces strength properties. Electroslag re-melting was effective in significantly increasing the fabricability of vacuum induction method VM-103, both with and without the 10 percent nickel addition. A specification for wrought VM-103 was developed and is included. Although thermomechanical processing improves lower temperature properties, no improvement occurs at temperatures at or above 2000 F (1093 C).

Post Ross procedure aortic right sinus of Valsalva fistula to right ventricle.

PubMed

Williams-Phillips, S

2011-12-01

Post Ross procedure complications have been limited predominantly to neoaortic valvular dilatation (10-30%) and insufficiency, right ventricular prosthetic deterioration or right ventricular pulmonary artery conduit obstruction. Arrhythmia has been documented to occur in a third of these patients. This is the first time that neoaortic right sinus of valsalva dissection and rupture to the right ventricle with a fistulous communication has occurred and been described, as far as the author is aware.

Performance analysis of non-coplanar synergetic maneuvers

NASA Astrophysics Data System (ADS)

Spriesterbach, Thomas P.

1991-12-01

Maneuvers employing atmospheric forces to assist in orbital changes hold potential for significant fuel savings over purely exoatmospheric propulsive methods. The term synergetic was coined to describe the combination of propulsive and atmospheric forces used by a maneuvering flight vehicle. This thesis concentrates on non-coplanar synergetic maneuvers using two different control methods for various lifting bodies over a range of heating rates and orbital speeds. The objective of this thesis is to study the aerocruise and aerobang maneuvers. The aerocruise maneuver was first studied more than twenty years ago and is commonly thought to be the fuel-optimal solution to a maneuver flown at a constant heating rate. A new maneuver, the aerobang, has recently raised doubts as to the optimality of the aerocrusie maneuver. The aerobang maneuver demonstrates the ability to yield a higher inclination change for a given amount of fuel as compared to the aerocruise maneuver. Within this thesis a computer code is developed to model both the aerobang and aerocruise maneuvers. It is shown that there exist flight regimes where the aerobang method is superior to the aerocruise method.

Detecting representations of recent and remote autobiographical memories in vmPFC and hippocampus

PubMed Central

Bonnici, Heidi M.; Chadwick, Martin J.; Lutti, Antoine; Hassabis, Demis; Weiskopf, Nikolaus; Maguire, Eleanor A.

2012-01-01

How autobiographical memories are represented in the human brain and whether this changes with time are questions central to memory neuroscience. Two regions in particular have been consistently implicated, the ventromedial prefrontal cortex (vmPFC) and the hippocampus, although their precise contributions are still contested. The key question in this debate, when reduced to its simplest form, concerns where information about specific autobiographical memories is located. Here we availed ourselves of the opportunity afforded by multi-voxel pattern analysis (MVPA) to provide an alternative to conventional neuropsychological and fMRI approaches, by detecting representations of individual autobiographical memories in patterns of fMRI activity. We examined whether information about specific recent (two weeks old) and remote (ten years old) autobiographical memories was represented in vmPFC and hippocampus, and other medial temporal and neocortical regions. vmPFC contained information about recent and remote autobiographical memories, although remote memories were more readily detected there, indicating that consolidation or a change of some kind had occurred. Information about both types of memory was also present in the hippocampus, suggesting it plays a role in the retrieval of vivid autobiographical memories regardless of remoteness. Interestingly, we also found that while recent and remote memories were both represented within anterior and posterior hippocampus, the latter nevertheless contained more information about remote memories. Thus, like vmPFC, the hippocampus too respected the distinction between recent and remote memories. Overall, these findings clarify and extend our view of vmPFC and hippocampus while also informing systems-level consolidation and providing clear targets for future studies. PMID:23175849

The Conserved Spore Coat Protein SpoVM Is Largely Dispensable in Clostridium difficile Spore Formation

PubMed Central

Ribis, John W.; Ravichandran, Priyanka; Putnam, Emily E.; Pishdadian, Keyan

2017-01-01

ABSTRACT The spore-forming bacterial pathogen Clostridium difficile is a leading cause of health care-associated infections in the United States. In order for this obligate anaerobe to transmit infection, it must form metabolically dormant spores prior to exiting the host. A key step during this process is the assembly of a protective, multilayered proteinaceous coat around the spore. Coat assembly depends on coat morphogenetic proteins recruiting distinct subsets of coat proteins to the developing spore. While 10 coat morphogenetic proteins have been identified in Bacillus subtilis, only two of these morphogenetic proteins have homologs in the Clostridia: SpoIVA and SpoVM. C. difficile SpoIVA is critical for proper coat assembly and functional spore formation, but the requirement for SpoVM during this process was unknown. Here, we show that SpoVM is largely dispensable for C. difficile spore formation, in contrast with B. subtilis. Loss of C. difficile SpoVM resulted in modest decreases (~3-fold) in heat- and chloroform-resistant spore formation, while morphological defects such as coat detachment from the forespore and abnormal cortex thickness were observed in ~30% of spoVM mutant cells. Biochemical analyses revealed that C. difficile SpoIVA and SpoVM directly interact, similarly to their B. subtilis counterparts. However, in contrast with B. subtilis, C. difficile SpoVM was not essential for SpoIVA to encase the forespore. Since C. difficile coat morphogenesis requires SpoIVA-interacting protein L (SipL), which is conserved exclusively in the Clostridia, but not the more broadly conserved SpoVM, our results reveal another key difference between C. difficile and B. subtilis spore assembly pathways. IMPORTANCE The spore-forming obligate anaerobe Clostridium difficile is the leading cause of antibiotic-associated diarrheal disease in the United States. When C. difficile spores are ingested by susceptible individuals, they germinate within the gut and

Sonographic evaluation of the bladder neck in continent and stress-incontinent women.

PubMed

Schaer, G N; Perucchini, D; Munz, E; Peschers, U; Koechli, O R; Delancey, J O

1999-03-01

To evaluate a new sonographic method to measure depth and width of proximal urethral dilation during coughing and Valsalva maneuver and to report its use in a group of stress-incontinent and continent women. Fifty-eight women were evaluated, 30 with and 28 without stress incontinence proven urodynamically, with a bladder volume of 300 mL and the subjects upright. Urethral pressure profiles at rest were performed with a 10 French microtip pressure catheter. Bladder neck dilation and descent were assessed by perineal ultrasound (5 MHz curved linear array transducer) with the help of ultrasound contrast medium (galactose suspension-Echovist-300), whereas abdominal pressure was assessed with an intrarectal balloon catheter. Statistical analysis used the nonparametric Mann-Whitney test. The depth and diameter of urethral dilation could be measured in all women. During Valsalva, all 30 incontinent women exhibited urethral dilation. One incontinent woman showed dilation only while performing a Valsalva maneuver, not during coughing. In the continent group, 12 women presented dilation during Valsalva and six during coughing. In continent women, dilation was visible only in those who were parous. Nulliparous women did not have dilation during Valsalva or coughing. Bladder neck descent was visible in continent and incontinent women. This method permits quantification of depth and diameter of bladder neck dilation, showing that both incontinent and continent women might have bladder neck dilation and that urinary continence can be established at different locations along the urethra in different women. Parity seems to be a main prerequisite for a proximal urethral defect with bladder neck dilation.

A Novel Method for Satellite Maneuver Prediction

NASA Astrophysics Data System (ADS)

Shabarekh, C.; Kent-Bryant, J.; Keselman, G.; Mitidis, A.

2016-09-01

A space operations tradecraft consisting of detect-track-characterize-catalog is insufficient for maintaining Space Situational Awareness (SSA) as space becomes increasingly congested and contested. In this paper, we apply analytical methodology from the Geospatial-Intelligence (GEOINT) community to a key challenge in SSA: predicting where and when a satellite may maneuver in the future. We developed a machine learning approach to probabilistically characterize Patterns of Life (PoL) for geosynchronous (GEO) satellites. PoL are repeatable, predictable behaviors that an object exhibits within a context and is driven by spatio-temporal, relational, environmental and physical constraints. An example of PoL are station-keeping maneuvers in GEO which become generally predictable as the satellite re-positions itself to account for orbital perturbations. In an earlier publication, we demonstrated the ability to probabilistically predict maneuvers of the Galaxy 15 (NORAD ID: 28884) satellite with high confidence eight days in advance of the actual maneuver. Additionally, we were able to detect deviations from expected PoL within hours of the predicted maneuver [6]. This was done with a custom unsupervised machine learning algorithm, the Interval Similarity Model (ISM), which learns repeating intervals of maneuver patterns from unlabeled historical observations and then predicts future maneuvers. In this paper, we introduce a supervised machine learning algorithm that works in conjunction with the ISM to produce a probabilistic distribution of when future maneuvers will occur. The supervised approach uses a Support Vector Machine (SVM) to process the orbit state whereas the ISM processes the temporal intervals between maneuvers and the physics-based characteristics of the maneuvers. This multiple model approach capitalizes on the mathematical strengths of each respective algorithm while incorporating multiple features and inputs. Initial findings indicate that the combined

Ada (Tradename) Compiler Validation Summary Report. International Business Machines Corporation. IBM Development System for the Ada Language for VM/CMS, Version 1.0. IBM 4381 (IBM System/370) under VM/CMS.

DTIC Science & Technology

1986-04-29

COMPILER VALIDATION SUMMARY REPORT: International Business Machines Corporation IBM Development System for the Ada Language for VM/CMS, Version 1.0 IBM 4381...tested using command scripts provided by International Business Machines Corporation. These scripts were reviewed by the validation team. Test.s were run...s): IBM 4381 (System/370) Operating System: VM/CMS, release 3.6 International Business Machines Corporation has made no deliberate extensions to the

Effect of spontaneous pushing versus Valsalva pushing in the second stage of labour on mother and fetus: a systematic review of randomised trials.

PubMed

Prins, M; Boxem, J; Lucas, C; Hutton, E

2011-05-01

To critically evaluate any benefit or harm for the mother and her baby of Valsalva pushing versus spontaneous pushing in the second stage of labour. Electronic databases from MEDLINE, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials were systematically searched (last search May 2010). The reference lists of retrieved studies were searched by hand and an internet hand search of master theses and dissertations was performed. No date or language restriction was used. Randomised controlled trials that compared instructed pushing with spontaneous pushing in the second stage of labour were considered. Studies were evaluated independently for methodological quality and appropriateness for inclusion by two authors (MP and JB). The primary outcome was instrumental/operative delivery. Other outcomes were length of labour, any perineal repair, bladder function, maternal satisfaction. Infant outcomes included low Apgar score < 7 after 5 minutes, umbilical arterial pH <7.2, admission to neonatal intensive care unit and serious neonatal morbidity or perinatal death. Three randomised controlled studies covering 425 primiparous women met the inclusion criteria. Women who used epidural analgesia were excluded in all three studies. No statistical difference was identified in the number of instrumental/operative deliveries (three studies; 425 women; relative risk 0.70; 95% CI 0.34-1.43), perineal repair, postpartum haemorrhage. Length of labour was significantly shorter in women who used the Valsalva pushing technique (three studies; 425 women; mean difference 18.59 minutes; 95% CI 0.46-36.73 minutes). Neonatal outcomes did not differ significantly. Urodynamic factors measured 3 months postpartum were negatively affected by Valsalva pushing. Measures of first urge to void and bladder capacity were decreased (one study; 128 women; mean difference respectively 41.50 ml, 95% CI 8.40-74.60, and 54.60 ml, 95% CI 13.31-95.89). The evidence from our review does not

Experimental visualization of rapid maneuvering fish

NASA Astrophysics Data System (ADS)

Daigh, S.; Techet, A. H.

2003-11-01

A freshwater tropical fish, Danio aequippinatus, is studied undergoing rapid turning and fast starting maneuvers. This agile species of fish is ideal for this study as it is capable of quick turning and darting motions up to 5g's. The fgish studied are 4-5 cm in length. The speed and kinematics of the maneuvering is determined by video analysis. Planar and stereo Particle Image Velocimetry (PIV) is used to map the vortical patterns in the wake of the maneuvering fish. PIV visualizations reveal that during C-shaped maneuvers a ring shaped jet vortex is formed. Fast starting behavior is also presented. PIV data is used to approixmate the thrust vectoring force produced during each maneuver.

Operational Maneuver: Function or Fiction?

DTIC Science & Technology

1996-02-12

characteristics of Vego’s operational functions. Although Schroedel’s model was constructed for the art and science of operational maneuver, his model...Schroedel, Joseph. "The Art and Science of operational Maneuver. " Fort Leavenworth, Kansas, SAMS Monograph, 1988, p. 5. 3 U.S. Joint Chiefs of Staff...Important Than Others? Ft. Leavenworth, Kansas: Study, 1986. Schroedel, Joseph. "The Art and Science of Operational Maneuver." Ft. Leavenworth, Kansas: SAMS

33 CFR 84.23 - Maneuvering light.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be placed...

33 CFR 84.23 - Maneuvering light.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be placed...

33 CFR 84.23 - Maneuvering light.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be placed...

33 CFR 84.23 - Maneuvering light.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be placed...

33 CFR 84.23 - Maneuvering light.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be placed...

Comparison of water and air charged transducer catheter pressures in the evaluation of cystometrogram and voiding pressure studies.

PubMed

McKinney, Timothy B; Babin, Elizabeth A; Ciolfi, Veronica; McKinney, Cynthia R; Shah, Nima

2018-04-01

Air-charged (AC) and water-perfused (WP) catheters have been evaluated for differences in measuring pressures for voiding dysfunction. Typically, a two-catheter system was used. We believe that simultaneous pressure measurements with AC and WP in a single catheter will provide analogous pressures for coughs, Valsalvas, and maximum pressures in voiding pressure studies (VPS). This IRB approved prospective study included 50 women over age 21. AC dual TDOC catheters were utilized. The water-filling channel served as the bladder filler and the water pressure readings. Patients were evaluated with empty bladders and at volumes of 50-100 mL, 200 mL, and maximum capacity with cough and Valsalva maneuvers. Comparative analysis was performed on maximum stress peak pressures. At maximum bladder capacity, VPS was done and maximum voiding pressure was recorded. Comparing coughs and Valsalva maneuvers pressures, there was significant increase in variability between AC and WP measurements with less than 50 mL volume (P < 0.001). Significant correlations were observed between AC and WP measurements for coughs and Valsalvas with bladder volume over 50 mL. Visual impression showed virtually identical tracings. Cough measurements had an average difference of 0.25 cmH 2 O (±8.81) and Valsalva measurements had an average difference of 3.15 cmH 2 O (±4.72). Thirty-eight women had usable maximum voiding pressure measurements and had a strong correlation. Cystometrogram and maximum voiding pressure measurements done with either water or air charged catheters will yield similarly accurate results and are comparable. Results suggest more variability at low bladder volumes <50 mL. © 2018 Wiley Periodicals, Inc.

Runtime Performance and Virtual Network Control Alternatives in VM-Based High-Fidelity Network Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoginath, Srikanth B; Perumalla, Kalyan S; Henz, Brian J

2012-01-01

In prior work (Yoginath and Perumalla, 2011; Yoginath, Perumalla and Henz, 2012), the motivation, challenges and issues were articulated in favor of virtual time ordering of Virtual Machines (VMs) in network simulations hosted on multi-core machines. Two major components in the overall virtualization challenge are (1) virtual timeline establishment and scheduling of VMs, and (2) virtualization of inter-VM communication. Here, we extend prior work by presenting scaling results for the first component, with experiment results on up to 128 VMs scheduled in virtual time order on a single 12-core host. We also explore the solution space of design alternatives formore » the second component, and present performance results from a multi-threaded, multi-queue implementation of inter-VM network control for synchronized execution with VM scheduling, incorporated in our NetWarp simulation system.« less

Maneuvers during legged locomotion

NASA Astrophysics Data System (ADS)

Jindrich, Devin L.; Qiao, Mu

2009-06-01

Maneuverability is essential for locomotion. For animals in the environment, maneuverability is directly related to survival. For humans, maneuvers such as turning are associated with increased risk for injury, either directly through tissue loading or indirectly through destabilization. Consequently, understanding the mechanics and motor control of maneuverability is a critical part of locomotion research. We briefly review the literature on maneuvering during locomotion with a focus on turning in bipeds. Walking turns can use one of several different strategies. Anticipation can be important to adjust kinematics and dynamics for smooth and stable maneuvers. During running, turns may be substantially constrained by the requirement for body orientation to match movement direction at the end of a turn. A simple mathematical model based on the requirement for rotation to match direction can describe leg forces used by bipeds (humans and ostriches). During running turns, both humans and ostriches control body rotation by generating fore-aft forces. However, whereas humans must generate large braking forces to prevent body over-rotation, ostriches do not. For ostriches, generating the lateral forces necessary to change movement direction results in appropriate body rotation. Although ostriches required smaller braking forces due in part to increased rotational inertia relative to body mass, other movement parameters also played a role. Turning performance resulted from the coordinated behavior of an integrated biomechanical system. Results from preliminary experiments on horizontal-plane stabilization support the hypothesis that controlling body rotation is an important aspect of stable maneuvers. In humans, body orientation relative to movement direction is rapidly stabilized during running turns within the minimum of two steps theoretically required to complete analogous maneuvers. During straight running and cutting turns, humans exhibit spring-mass behavior in the

Annual Vehicle Miles of Travel and Related Data : Procedures Used to Derive the Data Elements of the 1994 Table VM-1

DOT National Transportation Integrated Search

1996-06-01

The purpose of this report is to document the preparation of the 1994 Table VM-1, including data sources, assumptions, and estimating procedures. Table VM-1 describes vehicle distance traveled in miles, by highway category and vehicle type. VM-1 depi...

Acute Toxicity and Efficacy of Current Medical Countermeasures against VM in Guinea Pigs: A Comparison to VX and VR

DTIC Science & Technology

2013-05-01

and diazepam with and without pretreatment with pyridostigmine bromide . The 24 hr median lethal dose (MLD) of VM was determined using a sequential... pyridostigmine bromide . The 24 hr median lethal dose (MLD) of VM was determined using a sequential stage approach. The efficacy of medical...with and without pyridostigmine bromide (PB) pretreatment against lethal intoxication with VM, VR or VX. Methods Animals: Adult male Hartley

Platypnea-Orthodeoxia: An Unusual Case of Hypoxemia

DTIC Science & Technology

2011-01-01

Valsalva maneuver. Both are thought to open the PFO via increased right atrial filling. In a small study using transesophageal echocardiography , the...for stroke assessed by transesophageal echocardiography and carotid ultrasonography: the SPARC study. Stroke prevention: assessment of risk in a

Rolling Maneuver Load Alleviation using active controls

NASA Technical Reports Server (NTRS)

Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

1992-01-01

Rolling Maneuver Load Alleviation (RMLA) has been demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and actuation of the trailing edge inboard control surface pairs to maintain roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of 0.33, .38 and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

14 CFR 23.337 - Limit maneuvering load factors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factors. 23.337... Flight Loads § 23.337 Limit maneuvering load factors. (a) The positive limit maneuvering load factor n... airplanes; or (3) 6.0 for acrobatic category airplanes. (b) The negative limit maneuvering load factor may...

Orbital-Maneuver-Sequence Optimization

DTIC Science & Technology

1985-12-01

CLASSIFICATION OF THIS PAGE t j "" r --•.’-, LIST OF FIGURES * 2.1 Clohessy - Wiltshire Axes ....... .................. 17 3.1 Problem Geometry...13 Velocity Impulse ..... ..................... 13 The Clohessy - Wiltshire (CW) Equations ...... .. ... 14 3. INTERCEPT-MANEUVER-SEQUENCE STUDY...use of the Clohessy - Wiltshire near-circular-orbit model (Refs. 1, 2 and 3) which is adequate for low altitude maneuvering studies and attractive for

LANDSAT-5 orbit adjust maneuver report

NASA Technical Reports Server (NTRS)

Hassett, P. J.; Johnson, R. L.

1984-01-01

The orbit adjust maneuvers performed to raise the LANDSAT 5 spacecraft to mission altitude, synchronize it with the required groundtrack, and properly phase the spacecraft with LANDSAT-4 to provide an 8 day full Earth coverage cycle are described. Maneuver planning and evaluation procedures, data and analysis results for all maneuvers performed to date, the frozen orbit concept, and the phasing requirement between LANDSAT-4 and LANDSAT-5 are also examined.

14 CFR 25.333 - Flight maneuvering envelope.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight maneuvering envelope. 25.333 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.333 Flight maneuvering envelope. (a) General. The strength requirements must be met at each combination of...

14 CFR 25.333 - Flight maneuvering envelope.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight maneuvering envelope. 25.333 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.333 Flight maneuvering envelope. (a) General. The strength requirements must be met at each combination of...

14 CFR 27.337 - Limit maneuvering load factor.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 27.337... Limit maneuvering load factor. The rotorcraft must be designed for— (a) A limit maneuvering load factor... load factor not less than 2.0 and any negative limit maneuvering load factor of not less than −0.5 for...

14 CFR 29.337 - Limit maneuvering load factor.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 29.337... Limit maneuvering load factor. The rotorcraft must be designed for— (a) A limit maneuvering load factor... load factor not less than 2.0 and any negative limit maneuvering load factor of not less than −0.5 for...

14 CFR 23.1567 - Flight maneuver placard.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flight maneuver placard. 23.1567 Section 23... Information Markings and Placards § 23.1567 Flight maneuver placard. (a) For normal category airplanes, there... the approved acrobatic maneuvers and the recommended entry airspeed for each. If inverted flight...

14 CFR 23.1567 - Flight maneuver placard.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight maneuver placard. 23.1567 Section 23... Information Markings and Placards § 23.1567 Flight maneuver placard. (a) For normal category airplanes, there... the approved acrobatic maneuvers and the recommended entry airspeed for each. If inverted flight...

On the optimal two-impulse maneuver

NASA Technical Reports Server (NTRS)

Bonneau, F. G.; Diarra, C. M.

1992-01-01

An algorithm and a solution to the optimal two-impulse maneuver for the Ulysses spacecraft is presented. The option in which both maneuvers are designed using the critical plane strategy, which further reduces the propellant budget, is included. Results show savings of 12.4 and 16.7 m/s for full targeting and critical plane strategy, respectively. It is argued that this software will play an important role in the area of multimission maneuver design.

14 CFR 23.1507 - Operating maneuvering speed.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than VS√n...

14 CFR 23.1507 - Operating maneuvering speed.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than VS√n...

Balloon Dilation of the Cartilaginous Portion of the Eustachian Tube.

PubMed

Silvola, Juha; Kivekäs, Ilkka; Poe, Dennis S

2014-07-01

Studies of balloon Eustachian tuboplasty (BET) have shown encouraging results in small series with short follow-ups. Our pilot study suggested that patients with protracted otitis media with effusion (OME) or atelectasis of the tympanic membrane (TM) could benefit from BET. A prospective study where subjects act as their own controls. Patients from the pilot study and additional cases were enrolled in this cohort with long-term follow-up. Regional Academic Center. Out of 80 patients who underwent BET, 41 consecutive Eustachian tube (ET) operations were included. Subjects' inclusion criteria were OME and/or TM atelectasis, type B or C tympanograms, and inability to inflate their middle ears by Valsalva maneuver. All patients had longstanding ET dysfunction relieved only by repeated tympanostomies. Outcomes included ability to perform a Valsalva maneuver, audiometry, tympanometry, videoendoscopy of the ET with mucosal inflammation rating scores, and otomicroscopy. All cases were dilated successfully, without significant complications. Mean follow-up was 2.5 years (range, 1.5-4.2 years). Eighty percent (33/41) could do a Valsalva maneuver postoperatively; none of these ears required new tympanostomy tubes and subjective symptoms were relieved. Tympanometry results showed overall improvement. Nine patients had persistent perforations and 3 declined removal of the tube. Subjective symptoms were not relieved for 10% (4/41). The results show that BET can effectively improve ET function in ears with OME or atelectasis. The procedure is well tolerated and without significant complications. The follow-up continues and we are investigating possible reasons for failures. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

23 CFR 660.517 - Maneuver area roads.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving a...

Flight Test Maneuvers for Efficient Aerodynamic Modeling

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.

2011-01-01

Novel flight test maneuvers for efficient aerodynamic modeling were developed and demonstrated in flight. Orthogonal optimized multi-sine inputs were applied to aircraft control surfaces to excite aircraft dynamic response in all six degrees of freedom simultaneously while keeping the aircraft close to chosen reference flight conditions. Each maneuver was designed for a specific modeling task that cannot be adequately or efficiently accomplished using conventional flight test maneuvers. All of the new maneuvers were first described and explained, then demonstrated on a subscale jet transport aircraft in flight. Real-time and post-flight modeling results obtained using equation-error parameter estimation in the frequency domain were used to show the effectiveness and efficiency of the new maneuvers, as well as the quality of the aerodynamic models that can be identified from the resultant flight data.

Dynamics of Voluntary Cough Maneuvers

NASA Astrophysics Data System (ADS)

Naire, Shailesh

2008-11-01

Voluntary cough maneuvers are characterized by transient peak expiratory flows (PEF) exceeding the maximum expiratory flow-volume (MEFV) curve. In some cases, these flows can be well in excess of the MEFV, generally referred to as supramaximal flows. Understanding the flow-structure interaction involved in these maneuvers is the main goal of this work. We present a simple theoretical model for investigating the dynamics of voluntary cough and forced expiratory maneuvers. The core modeling idea is based on a 1-D model of high Reynolds number flow through flexible-walled tubes. The model incorporates key ingredients involved in these maneuvers: the expiratory effort generated by the abdominal and expiratory muscles, the glottis and the flexibility and compliance of the lung airways. Variations in these allow investigation of the expiratory flows generated by a variety of single cough maneuvers. The model successfully reproduces PEF which is shown to depend on the cough generation protocol, the glottis reopening time and the compliance of the airways. The particular highlight is in simulating supramaximal PEF for very compliant tubes. The flow-structure interaction mechanisms behind these are discussed. The wave speed theory of flow limitation is used to characterize the PEF. Existing hypotheses of the origin of PEF, from cough and forced expiration experiments, are also tested using this model.

Estimating maneuvers for precise relative orbit determination using GPS

NASA Astrophysics Data System (ADS)

Allende-Alba, Gerardo; Montenbruck, Oliver; Ardaens, Jean-Sébastien; Wermuth, Martin; Hugentobler, Urs

2017-01-01

Precise relative orbit determination is an essential element for the generation of science products from distributed instrumentation of formation flying satellites in low Earth orbit. According to the mission profile, the required formation is typically maintained and/or controlled by executing maneuvers. In order to generate consistent and precise orbit products, a strategy for maneuver handling is mandatory in order to avoid discontinuities or precision degradation before, after and during maneuver execution. Precise orbit determination offers the possibility of maneuver estimation in an adjustment of single-satellite trajectories using GPS measurements. However, a consistent formulation of a precise relative orbit determination scheme requires the implementation of a maneuver estimation strategy which can be used, in addition, to improve the precision of maneuver estimates by drawing upon the use of differential GPS measurements. The present study introduces a method for precise relative orbit determination based on a reduced-dynamic batch processing of differential GPS pseudorange and carrier phase measurements, which includes maneuver estimation as part of the relative orbit adjustment. The proposed method has been validated using flight data from space missions with different rates of maneuvering activity, including the GRACE, TanDEM-X and PRISMA missions. The results show the feasibility of obtaining precise relative orbits without degradation in the vicinity of maneuvers as well as improved maneuver estimates that can be used for better maneuver planning in flight dynamics operations.

Neonatal Morbidity Associated with Shoulder Dystocia Maneuvers

PubMed Central

Spain, Janine E.; Frey, Heather A.; Tuuli, Methodius G.; Colvin, Ryan; Macones, George A.; Cahill, Alison G.

2015-01-01

Objective To examine neonatal morbidity associated with different maneuvers used among term patients who experience a shoulder dystocia. Study Design A retrospective cohort study of all women who experienced a clinically diagnosed shoulder dystocia at term requiring obstetric maneuvers at a single tertiary care hospital from 2005-2008. We excluded women with major fetal anomaly, intrauterine death, multiple gestation, and preterm. Women exposed to Rubin maneuver, Wood's screw maneuver, or delivery of the posterior arm were compared to women delivered by McRoberts/suprapubic pressure only, which served as the reference group. The primary outcome was a composite morbidity of neonatal injury (defined as clavicular or humeral fracture or brachial plexus injury) and neonatal depression (defined as Apgar <7 at 5 minutes, arterial cord pH <7.1, CPAP use, intubation, or respiratory distress). Logistic regression was used to adjust for nulliparity and duration of shoulder dystocia, defined as time from delivery of fetal head to delivery of shoulders. Results Among the 231 women who met inclusion criteria, 135 were delivered by McRoberts/suprapubic pressure alone (57.9%), 83 women were exposed to Rubin maneuver, 53 women were exposed to Wood's screw, and 36 women were exposed to delivery of posterior arm. Individual maneuvers were not associated with composite morbidity, neonatal injury, or neonatal depression after adjusting for nulliparity and duration of shoulder dystocia. Conclusion We found no association between shoulder dystocia maneuvers and neonatal morbidity after adjusting for duration, a surrogate for severity. Our results demonstrate that clinicians should utilize the maneuver most likely to result in successful delivery. PMID:25291256

Rotor design for maneuver performance

NASA Technical Reports Server (NTRS)

Berry, John D.; Schrage, Daniel

1986-01-01

A method of determining the sensitivity of helicopter maneuver performance to changes in basic rotor design parameters is developed. Maneuver performance is measured by the time required, based on a simplified rotor/helicopter performance model, to perform a series of specified maneuvers. This method identifies parameter values which result in minimum time quickly because of the inherent simplicity of the rotor performance model used. For the specific case studied, this method predicts that the minimum time required is obtained with a low disk loading and a relatively high rotor solidity. The method was developed as part of the winning design effort for the American Helicopter Society student design competition for 1984/1985.

Neurocirculatory abnormalities in Parkinson disease with orthostatic hypotension: independence from levodopa treatment.

PubMed

Goldstein, David S; Eldadah, Basil A; Holmes, Courtney; Pechnik, Sandra; Moak, Jeffrey; Saleem, Ahmed; Sharabi, Yehonatan

2005-12-01

Patients with Parkinson disease often have orthostatic hypotension. Neurocirculatory abnormalities underlying orthostatic hypotension might reflect levodopa treatment. Sixty-six Parkinson disease patients (36 with orthostatic hypotension, 15 off and 21 on levodopa; 30 without orthostatic hypotension) had tests of reflexive cardiovagal gain (decrease in interbeat interval per unit decrease in systolic pressure during the Valsalva maneuver; orthostatic increase in heart rate per unit decrease in pressure); reflexive sympathoneural function (decrease in pressure during the Valsalva maneuver; orthostatic increment in plasma norepinephrine); and cardiac and extracardiac noradrenergic innervation (septal myocardial 6-[18F]fluorodopamine-derived radioactivity; supine plasma norepinephrine). Severity of orthostatic hypotension did not differ between the levodopa-untreated and levodopa-treated groups with Parkinson disease and orthostatic hypotension (-52+/-6 [SEM] versus -49+/-5 mm Hg systolic). The 2 groups had similarly low reflexive cardiovagal gain (0.84+/-0.23 versus 1.33+/-0.35 ms/mm Hg during Valsalva; 0.43+/-0.09 versus 0.27+/-0.06 bpm/mm Hg during orthostasis); and had similarly attenuated reflexive sympathoneural responses (97+/-29 versus 71+/-23 pg/mL during orthostasis; -82+/-10 versus -73+/-8 mm Hg during Valsalva). In patients off levodopa, plasma norepinephrine was lower in those with (193+/-19 pg/mL) than without (348+/-46 pg/mL) orthostatic hypotension. Low values for reflexive cardiovagal gain, sympathoneural responses, and noradrenergic innervation were strongly related to orthostatic hypotension. Parkinson disease with orthostatic hypotension features reflexive cardiovagal and sympathoneural failure and cardiac and partial extracardiac sympathetic denervation, independent of levodopa treatment.

Assessment of Eustachian tube function in patients with tympanic membrane retraction and in normal subjects.

PubMed

Canali, Inesângela; Petersen Schmidt Rosito, Letícia; Siliprandi, Bruno; Giugno, Cláudia; Selaimen da Costa, Sady

The diagnosis of Eustachian tube dysfunctions is essential for better understanding of the pathogenesis of chronic otitis media. A series of tests to assess tube function are described in the literature; however, they are methodologically heterogeneous, with differences ranging from application protocols to standardization of tests and their results. To evaluate the variation in middle ear pressure in patients with tympanic membrane retraction and in normal patients during tube function tests, as well as to evaluate intra-individual variation between these tests. An observational, contemporary, cross-sectional study was conducted, in which the factor under study was the variation in middle ear pressure during tube function tests (Valsalva maneuver, sniff test, Toynbee maneuver) in healthy patients and in patients with mild and moderate/severe tympanic retraction. A total of 38 patients (76 ears) were included in the study. Patients underwent tube function tests at two different time points to determine pressure measurements after each maneuver. Statistical analysis was performed using SPSS software, version 18.0, considering p-values <0.05 as statistically significant. Mean (standard deviation) age was 11 (2.72) years; 55.3% of patients were male and 44.7% female. The prevalence of type A tympanogram was higher among participants with healthy ears and those with mild retraction, whereas type C tympanograms were more frequent in the moderate/severe retraction group. An increase in middle ear pressure was observed during the Valsalva maneuver at the first time point evaluated in all three groups of ears (p=0.012). The variation in pressure was not significant either for the sniff test or for the Toynbee maneuver at the two time points evaluated (p≥0.05). Agreement between measurements obtained at the two different time points was weak to moderate for all tests in all three groups of ears, and the variations in discrepancy between measurements were higher in ears

Calorie restriction as an anti-invasive therapy for malignant brain cancer in the VM mouse.

PubMed

Shelton, Laura M; Huysentruyt, Leanne C; Mukherjee, Purna; Seyfried, Thomas N

2010-07-23

GBM (glioblastoma multiforme) is the most aggressive and invasive form of primary human brain cancer. We recently developed a novel brain cancer model in the inbred VM mouse strain that shares several characteristics with human GBM. Using bioluminescence imaging, we tested the efficacy of CR (calorie restriction) for its ability to reduce tumour size and invasion. CR targets glycolysis and rapid tumour cell growth in part by lowering circulating glucose levels. The VM-M3 tumour cells were implanted intracerebrally in the syngeneic VM mouse host. Approx. 12-15 days post-implantation, brains were removed and both ipsilateral and contralateral hemispheres were imaged to measure bioluminescence of invading tumour cells. CR significantly reduced the invasion of tumour cells from the implanted ipsilateral hemisphere into the contralateral hemisphere. The total percentage of Ki-67-stained cells within the primary tumour and the total number of blood vessels was also significantly lower in the CR-treated mice than in the mice fed ad libitum, suggesting that CR is anti-proliferative and anti-angiogenic. Our findings indicate that the VM-M3 GBM model is a valuable tool for studying brain tumour cell invasion and for evaluating potential therapeutic approaches for managing invasive brain cancer. In addition, we show that CR can be effective in reducing malignant brain tumour growth and invasion.

Neonatal morbidity associated with shoulder dystocia maneuvers.

PubMed

Spain, Janine E; Frey, Heather A; Tuuli, Methodius G; Colvin, Ryan; Macones, George A; Cahill, Alison G

2015-03-01

We sought to examine neonatal morbidity associated with different maneuvers used among term patients who experience a shoulder dystocia. We conducted a retrospective cohort study of all women who experienced a clinically diagnosed shoulder dystocia at term requiring obstetric maneuvers at a single tertiary care hospital from 2005 through 2008. We excluded women with major fetal anomaly, intrauterine death, multiple gestation, and preterm. Women exposed to Rubin maneuver, Wood's screw maneuver, or delivery of the posterior arm were compared to women delivered by McRoberts/suprapubic pressure only, which served as the reference group. The primary outcome was a composite morbidity of neonatal injury (defined as clavicular or humeral fracture or brachial plexus injury) and neonatal depression (defined as Apgar <7 at 5 minutes, arterial cord pH <7.1, continuous positive airway pressure use, intubation, or respiratory distress). Logistic regression was used to adjust for nulliparity and duration of shoulder dystocia, defined as time from delivery of fetal head to delivery of shoulders. Among the 231 women who met inclusion criteria, 135 were delivered by McRoberts/suprapubic pressure alone (57.9%), 83 women were exposed to Rubin maneuver, 53 women were exposed to Wood's screw, and 36 women were exposed to delivery of posterior arm. Individual maneuvers were not associated with composite morbidity, neonatal injury, or neonatal depression after adjusting for nulliparity and duration of shoulder dystocia. We found no association between shoulder dystocia maneuvers and neonatal morbidity after adjusting for duration, a surrogate for severity. Our results demonstrate that clinicians should utilize the maneuver most likely to result in successful delivery. Copyright © 2015 Elsevier Inc. All rights reserved.

Comparison of several maneuvering target tracking models

NASA Astrophysics Data System (ADS)

McIntyre, Gregory A.; Hintz, Kenneth J.

1998-07-01

The tracking of maneuvering targets is complicated by the fact that acceleration is not directly observable or measurable. Additionally, acceleration can be induced by a variety of sources including human input, autonomous guidance, or atmospheric disturbances. The approaches to tracking maneuvering targets can be divided into two categories both of which assume that the maneuver input command is unknown. One approach is to model the maneuver as a random process. The other approach assumes that the maneuver is not random and that it is either detected or estimated in real time. The random process models generally assume one of two statistical properties, either white noise or an autocorrelated noise. The multiple-model approach is generally used with the white noise model while a zero-mean, exponentially correlated acceleration approach is used with the autocorrelated noise model. The nonrandom approach uses maneuver detection to correct the state estimate or a variable dimension filter to augment the state estimate with an extra state component during a detected maneuver. Another issue with the tracking of maneuvering target is whether to perform the Kalman filter in Polar or Cartesian coordinates. This paper will examine and compare several exponentially correlated acceleration approaches in both Polar and Cartesian coordinates for accuracy and computational complexity. They include the Singer model in both Polar and Cartesian coordinates, the Singer model in Polar coordinates converted to Cartesian coordinates, Helferty's third order rational approximation of the Singer model and the Bar-Shalom and Fortmann model. This paper shows that these models all provide very accurate position estimates with only minor differences in velocity estimates and compares the computational complexity of the models.

Lithium Chloride can Induce Differentiation of Human Immortalized RenVm Cells into Dopaminergic Neurons.

PubMed

Soleimani, Mitra; Ghasemi, Nazem

2017-01-01

Stem cell-based therapy is a novel strategy for the treatment of neurodegenerative diseases. The transplantation of fully differentiated cells instead of stem cells in order to decrease serious adverse complications of stem cell therapy is a new idea. In this study, the effect of lithium chloride on dopaminergic differentiation of human immortalized RenVm cells was investigated in order to access a population of fully differentiated cells for transplantation in Parkinson disease. The immortalized RenVm cells were induced to dopaminergic differentiation using a neurobasal medium supplemented with N2 and different concentrations (1, 3, 6 mM ) of Lithium Chloride (LiCl) for 4, 8 and 12 days. The efficiency of dopaminergic differentiation was evaluated using immunocytochemistry and western blot techniques for tyrosine hydroxylase and β-catenin marker expression. Our results indicated that LiCl can promote dopaminergic differentiation of RenVm cells in a dose-dependent manner. It can be concluded that LiCl is able to facilitate dopaminergic differentiation of cultured cells by affecting Wnt-frizzled signaling pathway.

Experimental investigation of an astronaut maneuvering scheme.

NASA Technical Reports Server (NTRS)

Kane, T. R.; Headrick, M. R.; Yatteau, J. D.

1972-01-01

A new concept for astronaut maneuvering in space is proposed, and an experimental study undertaken to test this concept is described. The series of experiments performed appear to promise advantages over previously proposed schemes in terms of propellant economy, system weight, reliability, and safety. The simulation tests established the feasibility of the proposed maneuvering concept by showing that test subjects were able to place their bodies sufficiently near the reference position to avoid excessive angular momentum build-up; no difficulties were encountered in selecting self-rotation maneuvers suitable for effecting desired changes in orientation; and the execution of these maneuvers produced predicted reorientations without tiring the test subject significantly.

Optimal Propellant Maneuver Flight Demonstrations on ISS

NASA Technical Reports Server (NTRS)

Bhatt, Sagar; Bedrossian, Nazareth; Longacre, Kenneth; Nguyen, Louis

2013-01-01

In this paper, first ever flight demonstrations of Optimal Propellant Maneuver (OPM), a method of propulsive rotational state transition for spacecraft controlled using thrusters, is presented for the International Space Station (ISS). On August 1, 2012, two ISS reorientations of about 180deg each were performed using OPMs. These maneuvers were in preparation for the same-day launch and rendezvous of a Progress vehicle, also a first for ISS visiting vehicles. The first maneuver used 9.7 kg of propellant, whereas the second used 10.2 kg. Identical maneuvers performed without using OPMs would have used approximately 151.1kg and 150.9kg respectively. The OPM method is to use a pre-planned attitude command trajectory to accomplish a rotational state transition. The trajectory is designed to take advantage of the complete nonlinear system dynamics. The trajectory choice directly influences the cost of the maneuver, in this case, propellant. For example, while an eigenaxis maneuver is kinematically the shortest path between two orientations, following that path requires overcoming the nonlinear system dynamics, thereby increasing the cost of the maneuver. The eigenaxis path is used for ISS maneuvers using thrusters. By considering a longer angular path, the path dependence of the system dynamics can be exploited to reduce the cost. The benefits of OPM for the ISS include not only reduced lifetime propellant use, but also reduced loads, erosion, and contamination from thrusters due to fewer firings. Another advantage of the OPM is that it does not require ISS flight software modifications since it is a set of commands tailored to the specific attitude control architecture. The OPM takes advantage of the existing ISS control system architecture for propulsive rotation called USTO control mode1. USTO was originally developed to provide ISS Orbiter stack attitude control capability for a contingency tile-repair scenario, where the Orbiter is maneuvered using its robotic

Artificial immune system approach for air combat maneuvering

NASA Astrophysics Data System (ADS)

Kaneshige, John; Krishnakumar, Kalmanje

2007-04-01

Since future air combat missions will involve both manned and unmanned aircraft, the primary motivation for this research is to enable unmanned aircraft with intelligent maneuvering capabilities. During air combat maneuvering, pilots use their knowledge and experience of maneuvering strategies and tactics to determine the best course of action. As a result, we try to capture these aspects using an artificial immune system approach. The biological immune system protects the body against intruders by recognizing and destroying harmful cells or molecules. It can be thought of as a robust adaptive system that is capable of dealing with an enormous variety of disturbances and uncertainties. However, another critical aspect of the immune system is that it can remember how previous encounters were successfully defeated. As a result, it can respond faster to similar encounters in the future. This paper describes how an artificial immune system is used to select and construct air combat maneuvers. These maneuvers are composed of autopilot mode and target commands, which represent the low-level building blocks of the parameterized system. The resulting command sequences are sent to a tactical autopilot system, which has been enhanced with additional modes and an aggressiveness factor for enabling high performance maneuvers. Just as vaccinations train the biological immune system how to combat intruders, training sets are used to teach the maneuvering system how to respond to different enemy aircraft situations. Simulation results are presented, which demonstrate the potential of using immunized maneuver selection for the purposes of air combat maneuvering.

Spaceflight alters autonomic regulation of arterial pressure in humans

NASA Technical Reports Server (NTRS)

Fritsch-Yelle, Janice M.; Charles, John B.; Jones, Michele M.; Beightol, Larry A.; Eckberg, Dwain L.

1994-01-01

Spaceflight is associated with decreased orthostatic tolerance after landing. Short-duration spaceflight (4 - 5 days) impairs one neutral mechanism: the carotid baroreceptor-cardiac reflex. To understand the effects of longer-duration spaceflight on baroreflex function, we measured R-R interval power spectra, antecubital vein plasma catecholamine levels, carotid baroreceptor-cardiac reflex responses, responses to Valsalva maneuvers, and orthostatic tolerance in 16 astronauts before and after shuttle missions lasting 8 - 14 days. We found the following changes between preflight and landing day: (1) orthostatic tolerance decreased; (2) R-R interval spectral power in the 0.05- to 0.15-Hz band increased; (3) plasma norepinephrine and epinephrine levels increased; (4) the slope, range, and operational point of the carotid baroreceptor cardiac reflex response decreased; and (5) blood pressure and heart rate responses to Valsalva maneuvers were altered. Autonomic changes persisted for several days after landing. These results provide further evidence of functionally relevent reductions in parasympathetic and increases in sympathetic influences on arterial pressure control after spaceflight.

Slew maneuvers of Spacecraft Control Laboratory Experiment (SCOLE)

NASA Technical Reports Server (NTRS)

Kakad, Yogendra P.

1992-01-01

This is the final report on the dynamics and control of slew maneuvers of the Spacecraft Control Laboratory Experiment (SCOLE) test facility. The report documents the basic dynamical equation derivations for an arbitrary large angle slew maneuver as well as the basic decentralized slew maneuver control algorithm. The set of dynamical equations incorporate rigid body slew maneuver and three dimensional vibrations of the complete assembly comprising the rigid shuttle, the flexible beam, and the reflector with an offset mass. The analysis also includes kinematic nonlinearities of the entire assembly during the maneuver and the dynamics of the interactions between the rigid shuttle and the flexible appendage. The equations are simplified and evaluated numerically to include the first ten flexible modes to yield a model for designing control systems to perform slew maneuvers. The control problem incorporates the nonlinear dynamical equations and is expressed in terms of a two point boundary value problem.

Craniocervical hyperpneumatization with concurrent pneumorrhachis, pneumomediastinum, and subcutaneous emphysema in a weightlifter.

PubMed

Germino, Jessica C; Medverd, Jonathan R; Nguyen, Vicky T; Favinger, Jennifer L; Marder, Carrie P

2013-10-01

Acquired hyperpneumatization of the skull base and upper cervical vertebrae is extremely rare and is thought to occur in patients who habitually perform the Valsalva maneuver or engage in repetitive positive pressure activities such as scuba diving or free diving. Craniocervical hyperpneumatization has been reported to cause intracranial and extracranial pneumatoceles but is not generally considered as a cause of pneumorrhachis (air in the spinal canal). Pneumorrhachis is relatively rare, and usually occurs in a localized form, either in the cervical spine secondary to skull base fractures or in the thoracic spine secondary to pneumomediastinum or pneumothorax. Here, we report a case of extensive pneumorrhachis extending from the skull base to the thoracolumbar junction in association with marked axio-atlanto-occipital hyperpneumatization and pneumomediastinum. This unique constellation of findings likely resulted from complications of the Valsalva maneuver during strenuous exercise. To present a unique case of axio-atlanto-occipital hyperpneumatization with concurrent marked cervicothoracic pneumorrhachis, subcutaneous emphysema, and pneumomediastinum and to provide a review of the relevant literature, pathophysiology, and treatment strategies related to hyperpneumatization and pneumorrhachis. A unique case report from an urban medical center. A single case. Imaging findings and clinical history. Imaging data from a picture archiving and communication system and clinical data from an electronic medical record system were analyzed. A 58-year-old previously healthy man presented with 3 to 4 weeks of neck pain, shoulder pain, and intermittent hand and finger numbness that developed after weightlifting. On physical examination, he had mild hyperreflexia and decreased pinprick sensation within the T5-T8 dermatomes. Initial radiographic and computed tomography (CT) studies demonstrated extensive craniocervical hyperpneumatization involving the occipital bone, clivus

CernVM WebAPI - Controlling Virtual Machines from the Web

NASA Astrophysics Data System (ADS)

Charalampidis, I.; Berzano, D.; Blomer, J.; Buncic, P.; Ganis, G.; Meusel, R.; Segal, B.

2015-12-01

Lately, there is a trend in scientific projects to look for computing resources in the volunteering community. In addition, to reduce the development effort required to port the scientific software stack to all the known platforms, the use of Virtual Machines (VMs)u is becoming increasingly popular. Unfortunately their use further complicates the software installation and operation, restricting the volunteer audience to sufficiently expert people. CernVM WebAPI is a software solution addressing this specific case in a way that opens wide new application opportunities. It offers a very simple API for setting-up, controlling and interfacing with a VM instance in the users computer, while in the same time offloading the user from all the burden of downloading, installing and configuring the hypervisor. WebAPI comes with a lightweight javascript library that guides the user through the application installation process. Malicious usage is prohibited by offering a per-domain PKI validation mechanism. In this contribution we will overview this new technology, discuss its security features and examine some test cases where it is already in use.

Low Thrust Orbital Maneuvers Using Ion Propulsion

NASA Astrophysics Data System (ADS)

Ramesh, Eric

2011-10-01

Low-thrust maneuver options, such as electric propulsion, offer specific challenges within mission-level Modeling, Simulation, and Analysis (MS&A) tools. This project seeks to transition techniques for simulating low-thrust maneuvers from detailed engineering level simulations such as AGI's Satellite ToolKit (STK) Astrogator to mission level simulations such as the System Effectiveness Analysis Simulation (SEAS). Our project goals are as follows: A) Assess different low-thrust options to achieve various orbital changes; B) Compare such approaches to more conventional, high-thrust profiles; C) Compare computational cost and accuracy of various approaches to calculate and simulate low-thrust maneuvers; D) Recommend methods for implementing low-thrust maneuvers in high-level mission simulations; E) prototype recommended solutions.

Large Angle Satellite Attitude Maneuvers

NASA Technical Reports Server (NTRS)

Cochran, J. E.; Junkins, J. L.

1975-01-01

Two methods are proposed for performing large angle reorientation maneuvers. The first method is based upon Euler's rotation theorem; an arbitrary reorientation is ideally accomplished by rotating the spacecraft about a line which is fixed in both the body and in space. This scheme has been found to be best suited for the case in which the initial and desired attitude states have small angular velocities. The second scheme is more general in that a general class of transition trajectories is introduced which, in principle, allows transfer between arbitrary orientation and angular velocity states. The method generates transition maneuvers in which the uncontrolled (free) initial and final states are matched in orientation and angular velocity. The forced transition trajectory is obtained by using a weighted average of the unforced forward integration of the initial state and the unforced backward integration of the desired state. The current effort is centered around practical validation of this second class of maneuvers. Of particular concern is enforcement of given control system constraints and methods for suboptimization by proper selection of maneuver initiation and termination times. Analogous reorientation strategies which force smooth transition in angular momentum and/or rotational energy are under consideration.

14 CFR 25.337 - Limit maneuvering load factors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factors. 25.337... Conditions § 25.337 Limit maneuvering load factors. (a) Except where limited by maximum (static) lift... maneuvering load factors prescribed in this section. Pitching velocities appropriate to the corresponding pull...

14 CFR 23.151 - Acrobatic maneuvers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Acrobatic maneuvers. 23.151 Section 23.151 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... safely the acrobatic maneuvers for which certification is requested. Safe entry speeds for these...

14 CFR 23.151 - Acrobatic maneuvers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Acrobatic maneuvers. 23.151 Section 23.151 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... safely the acrobatic maneuvers for which certification is requested. Safe entry speeds for these...

Numerical investigation and experimental development on VM-PT cryocooler operating below 4 K

NASA Astrophysics Data System (ADS)

Zhang, Tong; Pan, Changzhao; Zhou, Yuan; Wang, Junjie

2016-12-01

Vuilleumier coupling pulse tube (VM-PT) cryocooler is a novel kind of cryocooler capable of attaining liquid helium temperature which had been experimentally verified. Depending on different coupling modes and phase shifters, VM-PT cryocooler can be designed in several configurations. This paper presents a numerical investigation on three typical types of VM-PT cryocoolers, which are gas-coupling mode with room temperature phase shifter (GCRP), gas-coupling mode with cold phase shifter (GCCP) and thermal-coupling mode with cold phase shifter (TCCP). Firstly, three configurations are optimized on operating parameters to attain lower no-load temperature. Then, based on the simulation results, distributions of acoustic power, enthalpy flow, pressure wave, and volume flow rate are presented and discussed to better understand the energy flow characteristics and coupling mechanism. Meanwhile, analyses of phase relationship and exergy loss are also performed. Furthermore, a GCCP experimental system with optimal comprehensive performance among three configurations was built and tested. Experimental results showed good consistency with the simulations. Finally, a no-load temperature of 3.39 K and cooling power of 9.75 mW at 4.2 K were obtained with a pressure ratio of 1.7, operating frequency of 1.22 Hz and mean pressure of 1.5 MPa.

14 CFR 25.1531 - Maneuvering flight load factors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering flight load factors. 25.1531... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the positive limit load factors determined from the maneuvering diagram in § 25.333(b), must be established. ...

Computer Associates International, CA-ACF2/VM Release 3.1

DTIC Science & Technology

1987-09-09

Associates CA-ACF2/VM Bibliography International Business Machines Corporation, IBM Virtual Machine/Directory Maintenance Program Logic Manual...publication number LY20-0889 International Business Machines International Business Machines Corporation, IBM System/370 Principles of Operation...publication number GA22-7000 International Business Machines Corporation, IBM Virtual Machine/Directory Maintenance Installation and System Administrator’s

Computing Satellite Maneuvers For A Repeating Ground Track

NASA Technical Reports Server (NTRS)

Shapiro, Bruce

1994-01-01

TOPEX/POSEIDON Ground Track Maintenance Maneuver Targeting Program (GTARG) assists in designing maneuvers to maintain orbit of TOPEX/POSEIDON satellite. Targeting strategies used either maximize time between maneuvers or force control band exit to occur at specified intervals. Runout mode allows for ground-track propagation without targeting. GTARG incorporates analytic mean-element propagation algorithm accounting for all perturbations known to cause significant variations in ground track. Perturbations include oblateness of Earth, luni-solar gravitation, drag, thrusts associated with impulsive maneuvers, and unspecified fixed forces acting on satellite in direction along trajectory. Written in VAX-FORTRAN.

Maneuvering strategies using CMGs

NASA Technical Reports Server (NTRS)

Oh, H. S.; Vadali, S. R.

1988-01-01

This paper considers control strategies for maneuvering spacecraft using Single-Gimbal Control Momentum Gyros (CMGs). A pyramid configuration using four gyros is utilized. Preferred initial gimbal angles for maximum utilization of CMG momentum are obtained for some known torque commands. Feedback control laws are derived from the stability point of view by using the Liapunov's Second Theorem. The gyro rates are obtained by the pseudo-inverse technique. The effect of gimbal rate bounds on controllability are studied for an example maneuver. Singularity avoidance is based on limiting the gyro rates depending on a singularity index.

46 CFR 109.564 - Maneuvering characteristics.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of each...

46 CFR 109.564 - Maneuvering characteristics.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of each...

46 CFR 109.564 - Maneuvering characteristics.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of each...

46 CFR 109.564 - Maneuvering characteristics.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of each...

46 CFR 109.564 - Maneuvering characteristics.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of each...

Sinus of Valsalva Pseudoaneurysm as a Sequela to Infective Endocarditis.

PubMed

Lee, Chin C; Siegel, Robert J

2016-02-01

Pseudoaneurysm is an uncommon sequela of infective endocarditis. We treated a 44-year-old man who had an active case of group B streptococcal infective endocarditis of the aortic valve despite no evidence of valvular dysfunction or vegetation on his initial transesophageal echocardiogram. After completing 6 weeks of intravenous antibiotic therapy, the patient developed a sinus of Valsalva pseudoaneurysm and severe aortic regurgitation caused by partial detachment of the left coronary cusp. We used a pericardial patch to close the pseudoaneurysm and repair the coronary cusp. This case shows the importance of routine clinical follow-up evaluation in infective endocarditis, even after completion of antibiotic therapy. Late sequelae associated with infective endocarditis or its therapy include recurrent infection, heart failure caused by valvular dysfunction (albeit delayed), and antibiotic toxicity such as aminoglycoside-induced nephropathy and vestibular toxicity.

Is Bariatric Surgery a Prophylaxis for Pelvic Floor Disorders?

PubMed

Pomian, Andrzej; Majkusiak, Wojciech; Lisik, Wojciech; Tomasik, Paweł; Horosz, Edyta; Zwierzchowska, Aneta; Kociszewski, Jacek; Barcz, Ewa

2018-06-01

Obesity is one of the well-documented risk factors of pelvic floor disorders (PFDs). The PFDs include urinary and fecal incontinence (UI, FI) and pelvic organ prolapse (POP). Surgery-induced weight loss improves different kinds of incontinence as well as POP symptoms. However, there is a lack of evidence how bariatric surgery influences pelvic floor anatomy and function in women without previous PFDs and whether it may be concerned as PFD prophylaxis tool. The present analysis is a prospective, non-randomized case-control study from January 2014 to September 2017. Participants underwent pelvic floor ultrasound examination with bladder neck position estimation at rest, during levator ani tension, and at Valsalva maneuver before surgery and 12-18 months after. Pelvic organ prolapse quantification (POPQ) > 2 stage and PFD complaints were the exclusion criteria. Fifty-nine patients underwent bariatric surgery (57 sleeve gastrectomy and 2 gastric bypass). Mean BMI decreased from 43.8 ± 5.9 to 29 ± 4.6 kg/m 2 after surgery (p < 0.001). Statistically significant higher position of the bladder neck at rest, during tension, and at Valsalva maneuver (p < 0.05) was shown after surgery. We did not demonstrate differences in bladder neck mobility and bladder neck elevation at tension after weight loss. Bariatric surgery is associated with a betterment of bladder neck position at rest, tension, and Valsalva maneuver in women without PFDs. We postulate that bariatric surgery may be a tool for PFD prevention. It does not improve levator ani function and does not limit bladder neck mobility, which implicates that it has no influence on preexisting pelvic dysfunction.

Sensor On-orbit Calibration and Characterization Using Spacecraft Maneuvers

NASA Technical Reports Server (NTRS)

Xiong, X.; Butler, Jim; Barnes, W. L.; Guenther, B.

2007-01-01

Spacecraft flight operations often require activities that involve different kinds of maneuvers for orbital adjustments (pitch, yaw, and roll). Different maneuvers, when properly planned and scheduled, can also be applied to support and/or to perform on-board sensor calibration and characterization. This paper uses MODIS (Moderate Resolution Imaging Spectroradiometer) as an example to illustrate applications of spacecraft maneuvers for Earth-observing sensors on-orbit calibration and characterization. MODIS is one of the key instruments for NASA's Earth Observing System (EOS) currently operated on-board the EOS Terra and Aqua spacecraft launched in December 1999 and May 2002, respectively. Since their launch, both Terra and Aqua spacecraft have made a number of maneuvers, specially the yaw and roll maneuvers, to support the MODIS on-orbit calibration and characterization. For both Terra and Aqua MODIS, near-monthly spacecraft roll maneuvers are executed for lunar observations. These maneuvers are carefully scheduled so that the lunar phase angles are nearly identical for each sensor's lunar observations. The lunar observations are used to track MODIS reflective solar bands (RSB) calibration stability and to inter-compare Terra and Aqua MODIS RSB calibration consistency. To date, two sets of yaw maneuvers (each consists of two series of 8 consecutive yaws) by the Terra spacecraft and one set by the Aqua spacecraft have been performed to validate MODIS solar diffuser (SD) bi-directional reflectance factor (BRF) and to derive SD screen transmission. Terra spacecraft pitch maneuvers, first made on March 26, 2003 and the second on April 14, 2003 (with the Moon in the spacecraft nadir view), have been applied to characterize MODIS thermal emissive bands (TEB) response versus scan angle (RVS). This is particularly important since the pre-launch TEB RSV measurements made by the sensor vendor were not successful. Terra MODIS TEB RVS obtained from pitch maneuvers have been

Multimodal pressure-flow method to assess dynamics of cerebral autoregulation in stroke and hypertension

PubMed Central

Novak, Vera; Yang, Albert CC; Lepicovsky, Lukas; Goldberger, Ary L; Lipsitz, Lewis A; Peng, Chung-Kang

2004-01-01

Background This study evaluated the effects of stroke on regulation of cerebral blood flow in response to fluctuations in systemic blood pressure (BP). The autoregulatory dynamics are difficult to assess because of the nonstationarity and nonlinearity of the component signals. Methods We studied 15 normotensive, 20 hypertensive and 15 minor stroke subjects (48.0 ± 1.3 years). BP and blood flow velocities (BFV) from middle cerebral arteries (MCA) were measured during the Valsalva maneuver (VM) using transcranial Doppler ultrasound. Results A new technique, multimodal pressure-flow analysis (MMPF), was implemented to analyze these short, nonstationary signals. MMPF analysis decomposes complex BP and BFV signals into multiple empirical modes, representing their instantaneous frequency-amplitude modulation. The empirical mode corresponding to the VM BP profile was used to construct the continuous phase diagram and to identify the minimum and maximum values from the residual BP (BPR) and BFV (BFVR) signals. The BP-BFV phase shift was calculated as the difference between the phase corresponding to the BPR and BFVR minimum (maximum) values. BP-BFV phase shifts were significantly different between groups. In the normotensive group, the BFVR minimum and maximum preceded the BPR minimum and maximum, respectively, leading to large positive values of BP-BFV shifts. Conclusion In the stroke and hypertensive groups, the resulting BP-BFV phase shift was significantly smaller compared to the normotensive group. A standard autoregulation index did not differentiate the groups. The MMPF method enables evaluation of autoregulatory dynamics based on instantaneous BP-BFV phase analysis. Regulation of BP-BFV dynamics is altered with hypertension and after stroke, rendering blood flow dependent on blood pressure. PMID:15504235

Multimodal pressure-flow method to assess dynamics of cerebral autoregulation in stroke and hypertension.

PubMed

Novak, Vera; Yang, Albert C C; Lepicovsky, Lukas; Goldberger, Ary L; Lipsitz, Lewis A; Peng, Chung-Kang

2004-10-25

This study evaluated the effects of stroke on regulation of cerebral blood flow in response to fluctuations in systemic blood pressure (BP). The autoregulatory dynamics are difficult to assess because of the nonstationarity and nonlinearity of the component signals. We studied 15 normotensive, 20 hypertensive and 15 minor stroke subjects (48.0 +/- 1.3 years). BP and blood flow velocities (BFV) from middle cerebral arteries (MCA) were measured during the Valsalva maneuver (VM) using transcranial Doppler ultrasound. A new technique, multimodal pressure-flow analysis (MMPF), was implemented to analyze these short, nonstationary signals. MMPF analysis decomposes complex BP and BFV signals into multiple empirical modes, representing their instantaneous frequency-amplitude modulation. The empirical mode corresponding to the VM BP profile was used to construct the continuous phase diagram and to identify the minimum and maximum values from the residual BP (BPR) and BFV (BFVR) signals. The BP-BFV phase shift was calculated as the difference between the phase corresponding to the BPR and BFVR minimum (maximum) values. BP-BFV phase shifts were significantly different between groups. In the normotensive group, the BFVR minimum and maximum preceded the BPR minimum and maximum, respectively, leading to large positive values of BP-BFV shifts. In the stroke and hypertensive groups, the resulting BP-BFV phase shift was significantly smaller compared to the normotensive group. A standard autoregulation index did not differentiate the groups. The MMPF method enables evaluation of autoregulatory dynamics based on instantaneous BP-BFV phase analysis. Regulation of BP-BFV dynamics is altered with hypertension and after stroke, rendering blood flow dependent on blood pressure.

A single bout of exhaustive exercise affects integrated baroreflex function after 16 days of head-down tilt

NASA Technical Reports Server (NTRS)

Engelke, K. A.; Doerr, D. F.; Convertino, V. A.

1995-01-01

We tested the hypothesis that one bout of maximal exercise performed 24 h before reambulation from 16 days of 6 degrees head-down tilt (HDT) could increase integrated baroreflex sensitivity. Isolated carotid-cardiac and integrated baroreflex function was assessed in seven subjects before and after two periods of HDT separated by 11 mo. On the last day of one HDT period, subjects performed a single bout of maximal cycle ergometry (exercise). Subjects did not exercise after the other HDT period (control). Carotid-cardiac baroreflex sensitivity was evaluated using a neck collar device. Integrated baroreflex function was assessed by recording heart rate (HR) and blood pressure (MAP) during a 15-s Valsalva maneuver (VM) at a controlled expiratory pressure of 30 mmHg. The ratio of change in HR to change in MAP (delta HR/ delta MAP) during phases II and IV of the VM was used as an index of cardiac baroreflex sensitivity. Baroreflex-mediated vasoconstriction was assessed by measuring the late phase II rise in MAP. Following HDT, carotid-cardiac baroreflex sensitivity was reduced (2.8 to 2.0 ms/mmHg; P = 0.05) as was delta HR/ delta MAP during phase II (-1.5 to -0.8 beats/mmHg; P = 0.002). After exercise, isolated carotid baroreflex activity and phase II delta HR/ delta MAP returned to pre-HDT levels but remained attenuated in the control condition. Phase IV delta HR/ delta MAP was not altered by HDT or exercise. The late phase II increase of MAP was 71% greater after exercise compared with control (7 vs. 2 mmHg; P = 0.041).(ABSTRACT TRUNCATED AT 250 WORDS).

The potential of value management (VM) to improve the consideration of energy efficiency within pre-construction

NASA Astrophysics Data System (ADS)

Tahir, Mohamad Zamhari; Nawi, Mohd Nasrun Mohd; Rajemi, Mohamad Farizal

2016-08-01

Energy demand and consumption in buildings will rise rapidly in the near future because of several social economics factors and this situation occurs not only in developed countries but also in developing countries such as Malaysia. There is demand towards building with energy efficiency features at this time, however most of the current buildings types are still being constructed with conventional designs, thus contribute to inefficient of energy consumption during the operation stage of the building. This paper presents the concept and the application of Value Management (VM) approach and its potential to improve consideration of energy efficiency within pre-construction process. Based on the relevant literatures, VM has provides an efficient and effective delivery system to fulfill the objectives and client's requirements. Generally in this paper, VM is discussed and scrutinized with reference to previous studies to see how these concepts contribute to better optimize the energy consumption in a building by seeking the best value energy efficiency through the design and construction process. This paper will not draw any conclusion but rather a preliminary research to propose the most energy efficiency measures to reliably accomplish a function that will meet the client's needs, desires and expectations. For further research in future, simple quantitative industry survey and VM workshops will be conducted to validate and further improve the research.

Correlation between bending of the VM region and pathogenicity of different Potato Spindle Tuber Viroid strains.

PubMed Central

Schmitz, A; Riesner, D

1998-01-01

Only 40 of the 359 nucleotides of Potato Spindle Tuber Viroid (PSTVd) represent the virulence-modulating (VM) region. Minor sequence variations in this domain distinguish mild from severe and even necrotic strains. Our recent hypothesis (Owens RA et al., 1996, Virology 222:144-158) that these differences result in varying degrees of bending of this part of the molecule could be tested experimentally. By in vitro transcription and partial double-strand formation, three types of model RNAs were prepared and subjected to electrophoresis in polyacrylamide gels: (1) Fragments representing the VM regions of six different PSTVd strains; (2) control fragments containing a bulge-loop as a rigid bend or an internal loop as a point of increased flexibility; and (3) dsRNAs of 36, 39, and 43 bp as length standards. Migration anomalies in gels of increasing percentage were evaluated and resulted in the following conclusions. In the absence of Mg2+, the VM regions differ only in terms of flexibility. Addition of Mg2+ induces conformational changes in these RNAs. All strains but Mild exhibit a rigid bend, and the angle of bending increases monotonically with the pathogenicity of the strain. The data are discussed in terms of a mechanism of pathogenicity, that protein-binding to the VM region is the primary pathogenic event. PMID:9769103

Space Object Maneuver Detection Algorithms Using TLE Data

NASA Astrophysics Data System (ADS)

Pittelkau, M.

2016-09-01

An important aspect of Space Situational Awareness (SSA) is detection of deliberate and accidental orbit changes of space objects. Although space surveillance systems detect orbit maneuvers within their tracking algorithms, maneuver data are not readily disseminated for general use. However, two-line element (TLE) data is available and can be used to detect maneuvers of space objects. This work is an attempt to improve upon existing TLE-based maneuver detection algorithms. Three adaptive maneuver detection algorithms are developed and evaluated: The first is a fading-memory Kalman filter, which is equivalent to the sliding-window least-squares polynomial fit, but computationally more efficient and adaptive to the noise in the TLE data. The second algorithm is based on a sample cumulative distribution function (CDF) computed from a histogram of the magnitude-squared |V|2 of change-in-velocity vectors (V), which is computed from the TLE data. A maneuver detection threshold is computed from the median estimated from the CDF, or from the CDF and a specified probability of false alarm. The third algorithm is a median filter. The median filter is the simplest of a class of nonlinear filters called order statistics filters, which is within the theory of robust statistics. The output of the median filter is practically insensitive to outliers, or large maneuvers. The median of the |V|2 data is proportional to the variance of the V, so the variance is estimated from the output of the median filter. A maneuver is detected when the input data exceeds a constant times the estimated variance.

Heterogeneous VM Replication: A New Approach to Intrusion Detection, Active Response and Recovery in Cloud Data Centers

DTIC Science & Technology

2015-08-17

from the same execution history, and cost-effective active response by proactively setting up standby VM replicas: migration from a compromised VM...the guest OSes system call code to be reused inside a “shadowed” portion of the context of the out-of- guest inspection program. Besides...by the rootkits in cloud environments. RootkitDet detects rootkits by identifying suspicious code region in the kernel space of guest OSes through

14 CFR 25.331 - Symmetric maneuvering conditions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Conditions § 25.331 Symmetric maneuvering conditions. (a) Procedure. For the analysis of the maneuvering... factor (at point A2 in § 25.333(b)), or the resulting tailplane normal load reaches its maximum...

Automated maneuver planning using a fuzzy logic algorithm

NASA Technical Reports Server (NTRS)

Conway, D.; Sperling, R.; Folta, D.; Richon, K.; Defazio, R.

1994-01-01

Spacecraft orbital control requires intensive interaction between the analyst and the system used to model the spacecraft trajectory. For orbits with right mission constraints and a large number of maneuvers, this interaction is difficult or expensive to accomplish in a timely manner. Some automation of maneuver planning can reduce these difficulties for maneuver-intensive missions. One approach to this automation is to use fuzzy logic in the control mechanism. Such a prototype system currently under development is discussed. The Tropical Rainfall Measurement Mission (TRMM) is one of several missions that could benefit from automated maneuver planning. TRMM is scheduled for launch in August 1997. The spacecraft is to be maintained in a 350-km circular orbit throughout the 3-year lifetime of the mission, with very small variations in this orbit allowed. Since solar maximum will occur as early as 1999, the solar activity during the TRMM mission will be increasing. The increasing solar activity will result in orbital maneuvers being performed as often as every other day. The results of automated maneuver planning for the TRMM mission will be presented to demonstrate the prototype of the fuzzy logic tool.

Maneuver Design and Calibration for the Genesis Spacecraft

NASA Technical Reports Server (NTRS)

Williams, Kenneth E.; Hong, Philip E.; Zietz, Richard P.; Han, Don

2000-01-01

Genesis is the fifth mission selected as part of NASA's Discovery Program. The objective of Genesis is to collect solar wind samples for a period of approximately two years while in a halo orbit about the Earth-Sun L I point. At the end of this period, the samples are to be returned to a specific recovery point on the Earth for subsequent analysis. This goal has never been attempted before and presents a formidable challenge in terms of mission design and operations, particularly planning and execution of propulsive maneuvers. To achieve a level of cost-effectiveness consistent with a Discovery-class mission, the Genesis spacecraft design was adapted to the maximum extent possible from designs used on earlier missions, such as Mars Global Surveyor (MGS) and Stardust, another sample collection mission. The spacecraft design for Genesis is shown. Spin stabilization was chosen for attitude control, in lieu of three-axis stabilization, with neither reaction wheels nor accelerometers included. This precludes closed-loop control of propulsive maneuvers and implies that any attitude changes, including spin changes and precessions, will behave like translational propulsive maneuvers and affect the spacecraft trajectory. Moreover, to minimize contamination risk to the samples collected, all thrusters were placed on the side opposite the sample collection canister. The orientation and characteristics of thrusters are indicated. For large maneuvers (>2.5 m/s), two 5 lbf thrusters will be used for delta v, with precession to the burn attitude, followed by spin-up from 1.6 to 10 rpm before the burn and spin down to 1.6 rpm afterwards, then precession back to the original spin attitude. For small maneuvers (<2.5 m/s), no spin change is needed and four 0.2 lbf thrusters are used for Av. Single or double 360 deg. precession changes are required whenever the desired delta v falls inside the two-way turn circle (about 0.4 m/s) based on the mass properties, spin rate and lever arm

Design and development of an IBM/VM menu system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cazzola, D.J.

1992-10-01

This report describes a full screen menu system developed using IBM's Interactive System Productivity Facility (ISPF) and the REXX programming language. The software was developed for the 2800 IBM/VM Electrical Computer Aided Design (ECAD) system. The system was developed to deliver electronic drawing definitions to a corporate drawing release system. Although this report documents the status of the menu system when it was retired, the methodologies used and the requirements defined are very applicable to replacement systems.

Design and development of an IBM/VM menu system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cazzola, D.J.

1992-10-01

This report describes a full screen menu system developed using IBM`s Interactive System Productivity Facility (ISPF) and the REXX programming language. The software was developed for the 2800 IBM/VM Electrical Computer Aided Design (ECAD) system. The system was developed to deliver electronic drawing definitions to a corporate drawing release system. Although this report documents the status of the menu system when it was retired, the methodologies used and the requirements defined are very applicable to replacement systems.

Development Of Maneuvering Autopilot For Flight Tests

NASA Technical Reports Server (NTRS)

Menon, P. K. A.; Walker, R. A.

1992-01-01

Report describes recent efforts to develop automatic control system operating under supervision of pilot and making airplane follow prescribed trajectories during flight tests. Report represents additional progress on this project. Gives background information on technology of control of test-flight trajectories; presents mathematical models of airframe, engine and command-augmentation system; focuses on mathematical modeling of maneuvers; addresses design of autopilots for maneuvers; discusses numerical simulation and evaluation of results of simulation of eight maneuvers under control of simulated autopilot; and presents summary and discussion of future work.

Superior herniation of the mediastinum presenting as an anterior neck mass on straining.

PubMed

McDougall, Catherine M; Culham, Gordon; Seear, Michael D; Chilvers, Mark A

2012-07-01

We report an infant with an anterior neck mass present only on straining. Airway fluoroscopy revealed this to be due to superior mediastinal herniation. Neck masses apparent only during Valsalva maneuver are rare and awareness of the differential diagnosis is important to avoid unnecessary investigation or surgery. Copyright © 2012 Wiley Periodicals, Inc.

Orbit Determination and Maneuver Detection Using Event Representation with Thrust-Fourier-Coefficients

NASA Astrophysics Data System (ADS)

Lubey, D.; Ko, H.; Scheeres, D.

The classical orbit determination (OD) method of dealing with unknown maneuvers is to restart the OD process with post-maneuver observations. However, it is also possible to continue the OD process through such unknown maneuvers by representing those unknown maneuvers with an appropriate event representation. It has been shown in previous work (Ko & Scheeres, JGCD 2014) that any maneuver performed by a satellite transitioning between two arbitrary orbital states can be represented as an equivalent maneuver connecting those two states using Thrust-Fourier-Coefficients (TFCs). Event representation using TFCs rigorously provides a unique control law that can generate the desired secular behavior for a given unknown maneuver. This paper presents applications of this representation approach to orbit prediction and maneuver detection problem across unknown maneuvers. The TFCs are appended to a sequential filter as an adjoint state to compensate unknown perturbing accelerations and the modified filter estimates the satellite state and thrust coefficients by processing OD across the time of an unknown maneuver. This modified sequential filter with TFCs is capable of fitting tracking data and maintaining an OD solution in the presence of unknown maneuvers. Also, the modified filter is found effective in detecting a sudden change in TFC values which indicates a maneuver. In order to illustrate that the event representation approach with TFCs is robust and sufficiently general to be easily adjustable, different types of measurement data are processed with the filter in a realistic LEO setting. Further, cases with mis-modeling of non-gravitational force are included in our study to verify the versatility and efficiency of our presented algorithm. Simulation results show that the modified sequential filter with TFCs can detect and estimate the orbit and thrust parameters in the presence of unknown maneuvers with or without measurement data during maneuvers. With no measurement

TOPEX/POSEIDON orbit maintenance maneuver design

NASA Technical Reports Server (NTRS)

Bhat, R. S.; Frauenholz, R. B.; Cannell, Patrick E.

1990-01-01

The Ocean Topography Experiment (TOPEX/POSEIDON) mission orbit requirements are outlined, as well as its control and maneuver spacing requirements including longitude and time targeting. A ground-track prediction model dealing with geopotential, luni-solar gravity, and atmospheric-drag perturbations is considered. Targeting with all modeled perturbations is discussed, and such ground-track prediction errors as initial semimajor axis, orbit-determination, maneuver-execution, and atmospheric-density modeling errors are assessed. A longitude targeting strategy for two extreme situations is investigated employing all modeled perturbations and prediction errors. It is concluded that atmospheric-drag modeling errors are the prevailing ground-track prediction error source early in the mission during high solar flux, and that low solar-flux levels expected late in the experiment stipulate smaller maneuver magnitudes.

vlPFC-vmPFC-Amygdala Interactions Underlie Age-Related Differences in Cognitive Regulation of Emotion.

PubMed

Silvers, Jennifer A; Insel, Catherine; Powers, Alisa; Franz, Peter; Helion, Chelsea; Martin, Rebecca E; Weber, Jochen; Mischel, Walter; Casey, B J; Ochsner, Kevin N

2017-07-01

Emotion regulation is a critical life skill that develops throughout childhood and adolescence. Despite this development in emotional processes, little is known about how the underlying brain systems develop with age. This study examined emotion regulation in 112 individuals (aged 6-23 years) as they viewed aversive and neutral images using a reappraisal task. On "reappraisal" trials, participants were instructed to view the images as distant, a strategy that has been previously shown to reduce negative affect. On "reactivity" trials, participants were instructed to view the images without regulating emotions to assess baseline emotional responding. During reappraisal, age predicted less negative affect, reduced amygdala responses and inverse coupling between the ventromedial prefrontal cortex (vmPFC) and amygdala. Moreover, left ventrolateral prefrontal (vlPFC) recruitment mediated the relationship between increasing age and diminishing amygdala responses. This negative vlPFC-amygdala association was stronger for individuals with inverse coupling between the amygdala and vmPFC. These data provide evidence that vmPFC-amygdala connectivity facilitates vlPFC-related amygdala modulation across development. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Cassini Solstice Mission Maneuver Experience: Year One

NASA Technical Reports Server (NTRS)

Wagner, Sean V.; Arrieta, Juan; Ballard, Christopher G.; Hahn, Yungsun; Stumpf, Paul W.; Valerino, Powtawche N.

2011-01-01

The Cassini-Huygens spacecraft began its four-year Prime Mission to study Saturn's system in July 2004. Two tour extensions followed: a two-year Equinox Mission beginning in July 2008 and a seven-year Solstice Mission starting in September 2010. This paper highlights Cassini maneuver activities from June 2010 through June 2011, covering the transition from the Equinox to Solstice Mission. This interval included 38 scheduled maneuvers, nine targeted Titan flybys, three targeted Enceladus flybys, and one close Rhea flyby. In addition, beyond the demanding nominal navigation schedule, numerous unforeseen challenges further complicated maneuver operations. These challenges will be discussed in detail.

A New Maneuver for Escape Trajectories

NASA Technical Reports Server (NTRS)

Adams, Robert B.

2008-01-01

This presentation put forth a new maneuver for escape trajectories and specifically sought to find an analytical approximation for medium thrust trajectories. In most low thrust derivations the idea is that escape velocity is best achieved by accelerating along the velocity vector. The reason for this is that change in specific orbital energy is a function of velocity and acceleration. However, Levin (1952) suggested that while this is a locally optimal solution it might not be a globally optimal one. Turning acceleration inward would drop periapse giving a higher velocity later in the trajectory. Acceleration at that point would be dotted against a higher magnitude V giving a greater rate of change of mechanical energy. The author then hypothesized that decelerating from the initial orbit and then accelerating at periapse would not lead to a gain in greater specific orbital energy--however, the hypothesis was incorrect. After considerable derivation it was determined that this new maneuver outperforms a direct burn when the overall DeltaV budget exceeds the initial orbital velocity (the author has termed this the Heinlein maneuver). The author provides a physical explanation for this maneuver and presents optimization analyses.

Maneuver Planning for Conjunction Risk Mitigation with Ground-track Control Requirements

NASA Technical Reports Server (NTRS)

McKinley, David

2008-01-01

The planning of conjunction Risk Mitigation Maneuvers (RMM) in the presence of ground-track control requirements is analyzed. Past RMM planning efforts on the Aqua, Aura, and Terra spacecraft have demonstrated that only small maneuvers are available when ground-track control requirements are maintained. Assuming small maneuvers, analytical expressions for the effect of a given maneuver on conjunction geometry are derived. The analytical expressions are used to generate a large trade space for initial RMM design. This trade space represents a significant improvement in initial maneuver planning over existing methods that employ high fidelity maneuver models and propagation.

Liver resection using a soft-coagulation system without the Pringle maneuver.

PubMed

Okamoto, Kojun; Koyama, Isamu; Toshimitsu, Yasuko; Aikawa, Masayasu; Okada, Katsuya; Ueno, Yosuke; Miyazawa, Mitsuo

2012-05-01

The Pringle maneuver is generally performed to reduce the amount of blood loss during hepatic resection. We have developed a method to sufficiently control blood loss during hepatectomy without applying the Pringle maneuver. This study was performed to determine the safety and operative blood loss in hepatectomy performed by this new method. We performed 102 hepatic resections without the Pringle maneuver. We retrospectively compared the short-term operative outcome between these 102 cases and another 75 hepatic resections performed with the Pringle maneuver. The resections without the Pringle maneuver were performed using a soft-coagulation system. The median length of the surgery using the soft-coagulation system without the Pringle maneuver was 135 minutes, significantly shorter than the surgical time required for resection with the Pringle maneuver 297 minutes (p<0.001). The median volume of operative blood loss was significantly lower in the non-Pringle-maneuver group (200cc vs. 704cc; p<0.001). Regarding postoperative liver function, AST, ALT, T-Bil and PT, levels were all significantly improved in the non-Pringle-maneuver group (p<0.01). Our data suggest that hepatic resection using a soft-coagulation system without the Pringle maneuver is extremely safe and effective in controlling bleeding.

Deployment and Operational Experiences with CernVM-FS at the GridKa Tier-1 Center

NASA Astrophysics Data System (ADS)

Alef, Manfred; Jäger, Axel; Petzold and, Andreas; Verstege, Bernhard

2012-12-01

In 2012 the GridKa Tier-1 computing center hosts 130 kHS06 computing resources and 14PB disk and 17PB tape space. These resources are shared between the four LHC VOs and a number of national and international VOs from high energy physics and other sciences. CernVM-FS has been deployed at GridKa to supplement the existing NFS-based system to access VO software on the worker nodes. It provides a solution tailored to the requirement of the LHC VOs. We will focus on the first operational experiences and the monitoring of CernVM-FS on the worker nodes and the squid caches.

Erythrocyte creatine as a marker of intravascular hemolysis due to left ventricular outflow tract obstruction in hypertrophic cardiomyopathy.

PubMed

Kubo, Toru; Okumiya, Toshika; Baba, Yuichi; Hirota, Takayoshi; Tanioka, Katsutoshi; Yamasaki, Naohito; Sugiura, Tetsuro; Doi, Yoshinori L; Kitaoka, Hiroaki

2016-03-01

Erythrocyte creatine, a marker of erythrocyte age that increases with shortening of erythrocyte survival, has been reported to be a quantitative and reliable marker for intravascular hemolysis. We hypothesized that hemolysis could also occur due to intraventricular obstruction in patients with hypertrophic cardiomyopathy (HCM). The purpose of this study was to examine the presence of subclinical hemolysis and the relation between intravascular hemolysis and intraventricular pressure gradient (IVPG). We measured erythrocyte creatine in 92 HCM patients. Twelve patients had left ventricular outflow tract obstruction (LVOTO), 4 had midventricular obstruction (MVO), and the remaining 76 were non-obstructive. Erythrocyte creatine levels ranged from 0.92 to 4.36μmol/g hemoglobin. Higher levels of erythrocyte creatine were associated with higher IVPG (r=0.437, p<0.001). If erythrocyte creatine levels are high (≥1.8μmol/g hemoglobin), subclinical hemolysis is considered to be present. Half of LVOTO patients and no MVO patients showed high erythrocyte creatine levels. Although non-obstructive patients did not show significant intraventricular obstruction at rest, some showed high erythrocyte creatine levels. When LVOT-PG was measured during the strain phase of the Valsalva maneuver in 20 non-obstructive patients, 7 of those 20 patients showed LVOTO. In the 20 patients, there was no relation between erythrocyte creatine levels and LVOT-PG before the Valsalva maneuver (r=0.125, p=0.600), whereas there was a significant correlation between erythrocyte creatine and LVOT-PG provoked by the Valsalva maneuver (r=0.695, p=0.001). There is biochemical evidence of subclinical hemolysis in patients with HCM, and this hemolysis seems to be associated with LVOTO provoked by daily physical activities. Copyright © 2015 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

GTARG - The TOPEX/Poseidon ground track maintenance maneuver targeting program

NASA Technical Reports Server (NTRS)

Shapiro, Bruce E.; Bhat, Ramachandra S.

1993-01-01

GTARG is a computer program used to design orbit maintenance maneuvers for the TOPEX/Poseidon satellite. These maneuvers ensure that the ground track is kept within +/-1 km with of an = 9.9 day exact repeat pattern. Maneuver parameters are determined using either of two targeting strategies: longitude targeting, which maximizes the time between maneuvers, and time targeting, in which maneuvers are targeted to occur at specific intervals. The GTARG algorithm propagates nonsingular mean elements, taking into account anticipated error sigma's in orbit determination, Delta v execution, drag prediction and Delta v quantization. A satellite unique drag model is used which incorporates an approximate mean orbital Jacchia-Roberts atmosphere and a variable mean area model. Maneuver Delta v magnitudes are targeted to precisely maintain either the unbiased ground track itself, or a comfortable (3 sigma) error envelope about the unbiased ground track.

Aircraft Maneuvers for the Evaluation of Flying Qualities and Agility. Volume 2. Maneuver Descriptions and Section Guide

DTIC Science & Technology

1993-08-01

Requirements to Design 2 Several of these maneuvers may be suitable for the development of design criteria or tactical utility studies . However, this...research was not intended to be a criteria development effort or a tactical ufiflity study . Instead, a sensitivity between each maneuver and various...utility studies because it contains measure of merit data and pilot comments for numerous desigp parameter variations. The Standard Evaluation

Improved Maneuver Criteria Evaluation Program

DTIC Science & Technology

1979-11-01

If the rotor rpm breakpoint (OMGBL2) is le :-s than the mininum rotor rpm (OMEGMN), then the rpm bleed :ate (OMGBDI) will be the only bleed rate used...VCP =60 PSU 1 EEF = 1 OMGBD1=2 OMGBD3=0 OMGRC2=0 VERR = 2 MPRINT= 1 OMEGMN=300 OMGBL.2=4 OMGBL4=0 OMGRD2=0 MUF = 1 BINERT:2860 TRPMMN= 0 OMGBD2=0 OMGBD4...height is within 2 feet of the measured height. These comparisons show that the MCEP maneuvers are accurate for simulating these types of maneuvers

[Interface compatibility between tooth-like yttria-stabilized tetragonal zirconia polycrystal by adding rare-earth oxide and Vita VM9 veneering porcelain].

PubMed

Gao, Yan; Zhang, Fu-qiang; He, Fan

2011-10-01

To evaluate the interface compatibility between tooth-like yttria-stabilized tetragonal zirconia polycrystal(Y-TZP) by adding rare-earth oxide and Vita VM9 veneering porcelain. Six kinds(S1,S2,S3,S4,S5,S6) of tooth-like yttria stabilized tetragonal zirconia polycrystal were made by introducing internal colorating technology to detect the thermal shock resistance and interface bonding strength with Vita VM9 Bsaedentin. Statistical analysis was performed using SAS6.12 software package. There was no gap between the layers via hot shocking test.The shear bonding strength between Y-TZP and VitaVM9 was higher and the value was (36.03±3.82) to (37.98±4.89) MPa. By adding rare-earth oxide to yttria-stabilized tetragonal zirconia polycrystal ,better compatibility between the layer (TZP and Vita VM9) can be formed which is of better interface integrate and available for clinical applications.

Cassini Maneuver Experience: Ending the Equinox Mission

NASA Technical Reports Server (NTRS)

Ballard, Christopher G.; Arrieta, Juan; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, Powtawche N.

2010-01-01

The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year interplanetary cruise, it entered a Saturnian orbit for a four-year Prime Mission in 2004 and began a two-year Equinox Mission in 2008. It has been approved for another seven-year mission, the Solstice Mission, starting in October 2010. This paper highlights significant maneuver activities performed from July 2009 to June 2010. We present results for the 45 maneuvers during this time. The successful navigation of the Cassini orbiter can be attributed in part to the accurate maneuver performance, which has greatly exceeded pre-launch expectations.

Aqua/Aura Updated Inclination Adjust Maneuver Performance Prediction Model

NASA Technical Reports Server (NTRS)

Boone, Spencer

2017-01-01

This presentation will discuss the updated Inclination Adjust Maneuver (IAM) performance prediction model that was developed for Aqua and Aura following the 2017 IAM series. This updated model uses statistical regression methods to identify potential long-term trends in maneuver parameters, yielding improved predictions when re-planning past maneuvers. The presentation has been reviewed and approved by Eric Moyer, ESMO Deputy Project Manager.

Ruptured congenital aneurysm of the right sinus of Valsalva into the right ventricle: with special reference to pathoanatomic and hemodynamic characteristics in symptomless cases.

PubMed

Chen, J J; Lien, W P; Chang, F Z; Lee, Y S; Hung, C R; Chu, S S; Wu, T L

1980-02-01

Clinical features of 19 cases with congenital aneurysm of the right sinus of Valsalva rupturing into the right ventricular outflow region (Type 1) were analysed in relation to their pathoanatomic lesions and hemodynamic alterations. Sixteen cases were operated with one surgical death. All were catheterized together with ascending aortographic study. Rupture of the aneurysm in many cases was silent or symptomless and progressive heart failure was not quite common. Symptomatology of the patients did not seem to be related entirely to status of the pathoanatomical lesions or hemodynamic alterations. Time of the rupture, and inherent right ventricular characteristics, tolerating volume overload rather well, might be, in part, responsible for its better prognosis in some cases. However, all patients with ruptured aneurysm of the sinus of Valsalva should be treated surgically. Bacterial endocarditis is a serious complication leading to death.

Fast-Solving Quasi-Optimal LS-S3VM Based on an Extended Candidate Set.

PubMed

Ma, Yuefeng; Liang, Xun; Kwok, James T; Li, Jianping; Zhou, Xiaoping; Zhang, Haiyan

2018-04-01

The semisupervised least squares support vector machine (LS-S 3 VM) is an important enhancement of least squares support vector machines in semisupervised learning. Given that most data collected from the real world are without labels, semisupervised approaches are more applicable than standard supervised approaches. Although a few training methods for LS-S 3 VM exist, the problem of deriving the optimal decision hyperplane efficiently and effectually has not been solved. In this paper, a fully weighted model of LS-S 3 VM is proposed, and a simple integer programming (IP) model is introduced through an equivalent transformation to solve the model. Based on the distances between the unlabeled data and the decision hyperplane, a new indicator is designed to represent the possibility that the label of an unlabeled datum should be reversed in each iteration during training. Using the indicator, we construct an extended candidate set consisting of the indices of unlabeled data with high possibilities, which integrates more information from unlabeled data. Our algorithm is degenerated into a special scenario of the previous algorithm when the extended candidate set is reduced into a set with only one element. Two strategies are utilized to determine the descent directions based on the extended candidate set. Furthermore, we developed a novel method for locating a good starting point based on the properties of the equivalent IP model. Combined with the extended candidate set and the carefully computed starting point, a fast algorithm to solve LS-S 3 VM quasi-optimally is proposed. The choice of quasi-optimal solutions results in low computational cost and avoidance of overfitting. Experiments show that our algorithm equipped with the two designed strategies is more effective than other algorithms in at least one of the following three aspects: 1) computational complexity; 2) generalization ability; and 3) flexibility. However, our algorithm and other algorithms have

Optimization of Maneuver Execution for Landsat-7 Routine Operations

NASA Technical Reports Server (NTRS)

Cox, E. Lucien, Jr.; Bauer, Frank H. (Technical Monitor)

2000-01-01

Multiple mission constraints were satisfied during a lengthy, strategic ascent phase. Once routine operations begin, the ongoing concern of maintaining mission requirements becomes an immediate priority. The Landsat-7 mission has tight longitude control box and Earth imaging that requires sub-satellite descending nodal equator crossing times to occur in a narrow 30minute range fifteen (15) times daily. Operationally, spacecraft maneuvers must'be executed properly to maintain mission requirements. The paper will discuss the importance of optimizing the altitude raising and plane change maneuvers, amidst known constraints, to satisfy requirements throughout mission lifetime. Emphasis will be placed not only on maneuver size and frequency but also on changes in orbital elements that impact maneuver execution decisions. Any associated trade-off arising from operations contingencies will be discussed as well. Results of actual altitude and plane change maneuvers are presented to clarify actions taken.

Permanent right-to-left shunt is the key factor in managing patent foramen ovale.

PubMed

Rigatelli, Gianluca; Dell'Avvocata, Fabio; Cardaioli, Paolo; Giordan, Massimo; Braggion, Gabriele; Aggio, Silvio; Chinaglia, Mauro; Mandapaka, Sangeeta; Kuruvilla, John; Chen, Jack P; Nanjundappa, Aravinda

2011-11-15

We sought to prospectively evaluate risk of stroke and impact of transcatheter patent foramen ovale (PFO) closure in patients with permanent right-to left shunt compared with those with Valsalva maneuver-induced right-to-left shunt. Pathophysiology and properly management of PFO still remain far from being fully clarified: in particular, the contribution of permanent right-to-left shunt remains unknown. Between March 2006 and October 2010, we enrolled 180 (mean age 44 ± 10.9 years, 98 women) of 320 consecutive patients referred to our center for transcatheter PFO closure, who had spontaneous permanent right-to-left shunt on transcranial Doppler and transthoracic/transesophageal echocardiography. All patients fulfilled the standard current indications for transcatheter closure and underwent preoperative transesophageal echocardiography and brain magnetic resonance imaging, with subsequent intracardiac echocardiographic-guided transcatheter PFO closure. We compared the clinical echocardiographic characteristics of these patients (Permanent Group) with the rest of 140 patients with right-to-left shunt only during Valsalva maneuver (Valsalva Group). Compared with the Valsalva Group patients, patients of the Permanent Group had increased frequency of multiple ischemic brain lesions on magnetic resonance imaging, previous recurrent stroke, previous peripheral arteries embolism, migraine with aura, and-more frequently-atrial septal aneurysm and prominent Eustachian valve. The presence of permanent shunt confers the highest risk of recurrent stroke (odds ratio: 5.9, 95% confidence interval: 2.0 to 12, p < 0.001). No differences were recorded between the 2 groups with regard to recurrence of ischemic events after the closure procedure. Despite its small-sample nature, our study suggests that patients with permanent right-to-left shunt have potentially a higher risk of paradoxical embolism compared with those without. Copyright © 2011 American College of Cardiology

Numerical study of a VM type multi-bypass pulse tube cryocooler operating at 4K

NASA Astrophysics Data System (ADS)

Pan, Changzhao; Zhang, Tong; Wang, Jue; Chen, Liubiao; Cui, Chen; Wang, Junjie; Zhou, Yuan

2017-12-01

VM cryocooler is one kind of Stirling type cryocooler working at low frequency. At present, we have obtained the liquid helium temperature by using a two-stage VM/pulse tube hybrid cryocooler. As a new kind of 4K cryocooler, there are many aspects need to be studied and optimized in detail. In order to reducing the vibration and improving the stability of this cryocooler, a pulse tube cryocooler was designed to get rid of the displacer in the first stage. This paper presents a detail numerical investigation on this pulse tube cryocooler by using the SAGE software. The low temperature phase shifters were adopted in this cryocooler, which were low temperature gas reservoir, low temperature double-inlet and multi-bypass. After optimizing, the structure parameters and the best diameters of orifice, multi-bypass and double-inlet were obtained. With the pressure ratio of about 1.6 and operating frequency 2Hz, this cryocooler could supply above 40mW cooling power at 4.2K, and the total input power needs no more than 60W at 77K. Based on the highest efficiency of 77K high capacity cryocooler, the overall efficiency of this VM type pulse tube cryocooler is above 0.5% relative Carnot efficient.

An Overview of Suomi NPP VIIRS Calibration Maneuvers

NASA Technical Reports Server (NTRS)

Butler, James J.; Xiong, Xiaoxiong; Barnes, Robert A.; Patt, Frederick S.; Sun, Junqiang; Chiang, Kwofu

2012-01-01

The first Visible Infrared Imager Radiometer Suite (VIIRS) instrument was successfully launched on-board the Suomi National Polar-orbiting Partnership (SNPP) spacecraft on October 28, 2011. Suomi NPP VIIRS observations are made in 22 spectral bands, from the visible (VIS) to the long-wave infrared (LWIR), and are used to produce 22 Environmental Data Records (EDRs) with a broad range of scientific applications. The quality of these VIIRS EDRs strongly depends on the quality of its calibrated and geo-located Sensor Date Records (SDRs). Built with a strong heritage to the NASA's EOS MODerate resolution Imaging Spectroradiometer (MODIS) instrument, the VIIRS is calibrated on-orbit using a similar set of on-board calibrators (OBC), including a solar diffuser (SD) and solar diffuser stability monitor (SDSM) system for the reflective solar bands (RSB) and a blackbody (BB) for the thermal emissive bands (TEB). On-orbit maneuvers of the SNPP spacecraft provide additional calibration and characterization data from the VIIRS instrument which cannot be obtained pre-launch and are required to produce the highest quality SDRs. These include multi-orbit yaw maneuvers for the characterization of SD and SDSM screen transmission, quasi-monthly roll maneuvers to acquire lunar observations to track sensor degradation in the visible through shortwave infrared, and a driven pitch-over maneuver to acquire multiple scans of deep space to determine TEB response versus scan angle (RVS). This paper pro-vides an overview of these three SNPP calibration maneuvers. Discussions are focused on their potential calibration and science benefits, pre-launch planning activities, and on-orbit scheduling and implementation strategies. Results from calibration maneuvers performed during the Intensive Calibration and Validation (ICV) period for the VIIRS sensor are illustrated. Also presented in this paper are lessons learned regarding the implementation of calibration spacecraft maneuvers on follow

An overview of Suomi NPP VIIRS calibration maneuvers

NASA Astrophysics Data System (ADS)

Butler, James J.; Xiong, Xiaoxiong; Barnes, Robert A.; Patt, Frederick S.; Sun, Junqiang; Chiang, Kwofu

2012-09-01

The first Visible Infrared Imager Radiometer Suite (VIIRS) instrument was successfully launched on-board the Suomi National Polar-orbiting Partnership (SNPP) spacecraft on October 28, 2011. Suomi NPP VIIRS observations are made in 22 spectral bands, from the visible (VIS) to the long-wave infrared (LWIR), and are used to produce 22 Environmental Data Records (EDRs) with a broad range of scientific applications. The quality of these VIIRS EDRs strongly depends on the quality of its calibrated and geo-located Sensor Date Records (SDRs). Built with a strong heritage to the NASA's EOS MODerate resolution Imaging Spectroradiometer (MODIS) instrument, the VIIRS is calibrated on-orbit using a similar set of on-board calibrators (OBC), including a solar diffuser (SD) and solar diffuser stability monitor (SDSM) system for the reflective solar bands (RSB) and a blackbody (BB) for the thermal emissive bands (TEB). Onorbit maneuvers of the SNPP spacecraft provide additional calibration and characterization data from the VIIRS instrument which cannot be obtained pre-launch and are required to produce the highest quality SDRs. These include multiorbit yaw maneuvers for the characterization of SD and SDSM screen transmission, quasi-monthly roll maneuvers to acquire lunar observations to track sensor degradation in the visible through shortwave infrared, and a driven pitch-over maneuver to acquire multiple scans of deep space to determine TEB response versus scan angle (RVS). This paper provides an overview of these three SNPP calibration maneuvers. Discussions are focused on their potential calibration and science benefits, pre-launch planning activities, and on-orbit scheduling and implementation strategies. Results from calibration maneuvers performed during the Intensive Calibration and Validation (ICV) period for the VIIRS sensor are illustrated. Also presented in this paper are lessons learned regarding the implementation of calibration spacecraft maneuvers on follow

Time-optical spinup maneuvers of flexible spacecraft

NASA Technical Reports Server (NTRS)

Singh, G.; Kabamba, P. T.; Mcclamroch, N. H.

1990-01-01

Attitude controllers for spacecraft have been based on the assumption that the bodies being controlled are rigid. Future spacecraft, however, may be quite flexible. Many applications require spinning up/down these vehicles. In this work the minimum time control of these maneuvers is considered. The time-optimal control is shown to possess an important symmetry property. Taking advantage of this property, the necessary and sufficient conditions for optimality are transformed into a system of nonlinear algebraic equations in the control switching times during one half of the maneuver, the maneuver time, and the costates at the mid-maneuver time. These equations can be solved using a homotopy approach. Control spillover measures are introduced and upper bounds on these measures are obtained. For a special case these upper bounds can be expressed in closed form for an infinite dimensional evaluation model. Rotational stiffening effects are ignored in the optimal control analysis. Based on a heuristic argument a simple condition is given which justifies the omission of these nonlinear effects. This condition is validated by numerical simulation.

A near-optimal guidance for cooperative docking maneuvers

NASA Astrophysics Data System (ADS)

Ciarcià, Marco; Grompone, Alessio; Romano, Marcello

2014-09-01

In this work we study the problem of minimum energy docking maneuvers between two Floating Spacecraft Simulators. The maneuvers are planar and conducted autonomously in a cooperative mode. The proposed guidance strategy is based on the direct method known as Inverse Dynamics in the Virtual Domain, and the nonlinear programming solver known as Sequential Gradient-Restoration Algorithm. The combination of these methods allows for the quick prototyping of near-optimal trajectories, and results in an implementable tool for real-time closed-loop maneuvering. The experimental results included in this paper were obtained by exploiting the recently upgraded Floating Spacecraft-Simulator Testbed of the Spacecraft Robotics Laboratory at the Naval Postgraduate School. A direct performances comparison, in terms of maneuver energy and propellant mass, between the proposed guidance strategy and a LQR controller, demonstrates the effectiveness of the method.

Helicopter Pilot Performance for Discrete-maneuver Flight Tasks

NASA Technical Reports Server (NTRS)

Heffley, R. K.; Bourne, S. M.; Hindson, W. S.

1984-01-01

This paper describes a current study of several basic helicopter flight maneuvers. The data base consists of in-flight measurements from instrumented helicopters using experienced pilots. The analysis technique is simple enough to apply without automatic data processing, and the results can be used to build quantitative matah models of the flight task and some aspects of the pilot control strategy. In addition to describing the performance measurement technqiue, some results are presented which define the aggressiveness and amplitude of maneuvering for several lateral maneuvers including turns and sidesteps.

Planar reorientation maneuvers of space multibody systems using internal controls

NASA Technical Reports Server (NTRS)

Reyhanoglu, Mahmut; Mcclamroch, N. H.

1992-01-01

In this paper a reorientation maneuvering strategy for an interconnection of planar rigid bodies in space is developed. It is assumed that there are no exogeneous torques, and torques generated by joint motors are used as means of control so that the total angular momentum of the multibody system is a constant, assumed to be zero in this paper. The maneuver strategy uses the nonintegrability of the expression for the angular momentum. We demonstrate that large-angle maneuvers can be designed to achieve an arbitrary reorientation of the multibody system with respect to an inertial frame. The theoretical background for carrying out the required maneuvers is briefly summarized. Specifications and computer simulations of a specific reorientation maneuver, and the corresponding control strategies, are described.

Method for Studying Helicopter Longitudinal Maneuver Stability

NASA Technical Reports Server (NTRS)

Amer, Kenneth B

1954-01-01

A theoretical analysis of helicopter maneuver stability is made and the results are compared with experimental results for both a single and a tandem rotor helicopter. Techniques are described for measuring in flight the significant stability derivatives for use with the theory to aid in design studies of means for achieving marginal maneuver stability for a prototype helicopter.

33 CFR 83.34 - Maneuvering and warning signals (Rule 34).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Maneuvering and warning signals... SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.34 Maneuvering and warning signals... maneuvering and warning signals. (g) Power-driven vessels leaving dock or berth. When a power-driven vessel is...

33 CFR 83.34 - Maneuvering and warning signals (Rule 34).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Maneuvering and warning signals... SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.34 Maneuvering and warning signals... maneuvering and warning signals. (g) Power-driven vessels leaving dock or berth. When a power-driven vessel is...

Cassini Maneuver Experience for the Fourth Year of the Solstice Mission

NASA Technical Reports Server (NTRS)

Vaquero, Mar; Hahn, Yungsun; Stumpf, Paul; Valerino, Powtawche; Wagner, Sean; Wong, Mau

2014-01-01

After sixteen years of successful mission operations and invaluable scientific discoveries, the Cassini orbiter continues to tour Saturn on the most complex gravity-assist trajectory ever flown. To ensure that the end-of-mission target of September 2017 is achieved, propellant preservation is highly prioritized over maneuver cycle minimization. Thus, the maneuver decision process, which includes determining whether a maneuver is performed or canceled, designing a targeting strategy and selecting the engine for execution, is being continuously re-evaluated. This paper summarizes the maneuver experience throughout the fourth year of the Solstice Mission highlighting 27 maneuvers targeted to nine Titan flybys.

A Semi-Empirical Noise Modeling Method for Helicopter Maneuvering Flight Operations

NASA Technical Reports Server (NTRS)

Greenwood, Eric; Schmitz, Fredric; Sickenberger, Richard D.

2012-01-01

A new model for Blade-Vortex Interaction noise generation during maneuvering flight is developed in this paper. Acoustic and performance data from both flight and wind tunnels are used to derive a non-dimensional and analytical performance/acoustic model that describes BVI noise in steady flight. The model is extended to transient maneuvering flight (pure pitch and roll transients) by using quasisteady assumptions throughout the prescribed maneuvers. Ground noise measurements, taken during maneuvering flight of a Bell 206B helicopter, show that many of the noise radiation details are captured. The result is a computationally efficient Blade-Vortex Interaction noise model with sufficient accuracy to account for transient maneuvering flight. The code can be run in real time to predict transient maneuver noise and is suitable for use in an acoustic mission-planning tool.

Operational Experiences in Planning and Reconstructing Aqua Inclination Maneuvers

NASA Technical Reports Server (NTRS)

Rand, David; Reilly, Jacqueline; Schiff, Conrad

2004-01-01

As the lead satellite in NASA's growing Earth Observing System (EOS) PM constellation, it is increasingly critical that Aqua maintain its various orbit requirements. The two of interest for this paper are maintaining an orbit inclination that provides for a consistent mean local time and a semi-major Axis (SMA) that allows for ground track repeatability. Maneuvers to adjust the orbit inclination involve several flight dynamics constraints and complexities which make planning such maneuvers challenging. In particular, coupling between the orbital and attitude degrees of freedom lead to changes in SMA when changes in inclination are effected. A long term mission mean local time trend analysis was performed in order to determine the size and placement of the required inclination maneuvers. Following this analysis, detailed modeling of each burn and its Various segments was performed to determine its effects on the immediate orbit state. Data gathered from an inclination slew test of the spacecraft and first inclination maneuver uncovered discrepancies in the modeling method that were investigated and resolved. The new modeling techniques were applied and validated during the second spacecraft inclination maneuver. These improvements should position Aqua to successfully complete a series of inclination maneuvers in the fall of 2004. The following paper presents the events and results related

Numerical study of a gas coupled VM-PT hybrid cryocooler using 3He as the working fluid

NASA Astrophysics Data System (ADS)

Wang, J.; Pan, C. Z.; Zhang, T.; Wang, J. J.; Zhou, Y.

2017-12-01

The two-stage Vuilleumier gas-coupling pulse tube cryocooler (VM-PT) is one kind of novel low-frequency cryocoolers. In this gas-coupled form, the single stage Vuilleumier cryocooler serves as both pressure wave generator and a pre-cooler for coaxial pulse tube. Compared with the most commercialized GM and GM pulse tube cryocooler, the two-stage VM-PT cryocooler is characterized by its high stability, compact size and thermal actuation which are indispensable for space application. It has already been verified experimentally that this cryocooler can obtain 9.75mW@4.2K and the lowest no-load temperature 3.39K when 4He as the working fluid. However, such refrigerating capacity seems not enough for further application. 3He as a more potential substitution of 4He has better physical properties to improve performance, which has been studied in GM type and Stirling pulse tube cryocooler. For further optimization, a numerical study on the specific performance of two-stage VM-PT cryocooler using 3He is carried out in the present paper though Sage software. Working at the frequency of 1.0Hz and the pressure of 0.8MPa, the two-stage VM-PT cryocooler with 3He obtained 50mW@4.06K. The usage of 3He was 0.0038kg, about 30L under STP. At 4.2K, using 3He can obtain 58mW cooling power and 0.49% relative Carnot efficiency, about 1.6 times higher than using 4He.

14 CFR 25.1531 - Maneuvering flight load factors.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maneuvering flight load factors. 25.1531 Section 25.1531 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the...

14 CFR 25.1531 - Maneuvering flight load factors.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maneuvering flight load factors. 25.1531 Section 25.1531 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the...

Cassini-Huygens Maneuver Experience: Ending the Prime Mission

NASA Technical Reports Server (NTRS)

Goodson, Troy D.; Ballard, Christopher G.; Gist, Emily M.; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, Powtawche N.

2008-01-01

The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year cruise, it entered a Saturnian orbit for a four-year, prime mission. This paper highlights significant maneuver activities performed during the last year of the prime mission. Specifically, results of 42 recent maneuvers are presented. Many maneuvers have been skipped, saving fuel and flight team effort. The system has performed more accurately than the pre-launch expectations and requirements. This is in large part why the Cassini-Huygens spacecraft has been navigated with tremendous success during the prime mission.

Maneuver Warfare revisited: a plea for balance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamilton, M,R.

1986-04-01

This paper is a plea for balance in the current pursuit of understanding of the concept and the teaching of Maneuver Warfare. It specifically addresses the need for a more-complete analysis of some of the more-common historical examples commonly offered as examples of the supremecy of Maneuver Warfare. The paper in no way disagrees with the desirability of conducting the kinds of operations associated with the ill-defined concepts offered by advocates of Maneuver Warfare but suggests that the desirable results of historical battles may be too readily ascribed to the dynamic, offensive actions of the victorious side. Secondly, the papermore » points out the lack of utility and applicability of some common buzzwords being used in today's Army. Specifically assailed is the concept of turning within a decision cycle. The paper describes the reasons that this commonly used phrase has little applicability to ground warfare. Finally, the paper mentions the tendency for the Maneuver Warfare camp to cloud discussion of doctrine in a kind of intellectualism and elitism that has no use in forming the necessary consensus demanded by doctrine.« less

Optimizing interplanetary trajectories with deep space maneuvers

NASA Astrophysics Data System (ADS)

Navagh, John

1993-09-01

Analysis of interplanetary trajectories is a crucial area for both manned and unmanned missions of the Space Exploration Initiative. A deep space maneuver (DSM) can improve a trajectory in much the same way as a planetary swingby. However, instead of using a gravitational field to alter the trajectory, the on-board propulsion system of the spacecraft is used when the vehicle is not near a planet. The purpose is to develop an algorithm to determine where and when to use deep space maneuvers to reduce the cost of a trajectory. The approach taken to solve this problem uses primer vector theory in combination with a non-linear optimizing program to minimize Delta(V). A set of necessary conditions on the primer vector is shown to indicate whether a deep space maneuver will be beneficial. Deep space maneuvers are applied to a round trip mission to Mars to determine their effect on the launch opportunities. Other studies which were performed include cycler trajectories and Mars mission abort scenarios. It was found that the software developed was able to locate quickly DSM's which lower the total Delta(V) on these trajectories.

On-Orbit Maneuver Calibrations for the Stardust Spacecraft

NASA Technical Reports Server (NTRS)

Nandi, Sumita; Kennedy, Brian; Williams, Kenneth E.; Byrnes, Dennis V.

2006-01-01

The Stardust spacecraft, launched February 7, 1999, successfully delivered its sample return capsule to the Utah Test and Training Range on January 15, 2006. The entry maneuver strategy included a trajectory correction at entry minus 10 days (TCM18) targeted to entry with the inclusion of a final biased fixed direction maneuver at entry minus 29 hours (TCM19). To meet the stringent entry targeting requirements necessary for human safety and capsule integrity, a campaign of maneuver calibrations were undertaken in summers of 2003 and 2005 to improve performance for both maneuvers. The results of the calibration program are reported here. The in-flight calibrations included a series of several turns to various final attitudes via deadband walks about each of the three spacecraft axes, as well as 12 in-place burns with magnitudes between 0.5 and 1.0 m/s, the range initially expected for TCM19. The turn and burn calibrations as well as the performance of TCM 17, 18 and 19 are discussed.

Performance Evaluation of Evasion Maneuvers for Parallel Approach Collision Avoidance

NASA Technical Reports Server (NTRS)

Winder, Lee F.; Kuchar, James K.; Waller, Marvin (Technical Monitor)

2000-01-01

Current plans for independent instrument approaches to closely spaced parallel runways call for an automated pilot alerting system to ensure separation of aircraft in the case of a "blunder," or unexpected deviation from the a normal approach path. Resolution advisories by this system would require the pilot of an endangered aircraft to perform a trained evasion maneuver. The potential performance of two evasion maneuvers, referred to as the "turn-climb" and "climb-only," was estimated using an experimental NASA alerting logic (AILS) and a computer simulation of relative trajectory scenarios between two aircraft. One aircraft was equipped with the NASA alerting system, and maneuvered accordingly. Observation of the rates of different types of alerting failure allowed judgement of evasion maneuver performance. System Operating Characteristic (SOC) curves were used to assess the benefit of alerting with each maneuver.

[Interface bond and compatibility between Mark II machining ceramic and vita VM9 veneering porcelain].

PubMed

Liu, Tian-Shuang; Li, Zhen-Chun; Chen, Xiao-Dong

2009-04-01

To investigate the interface bond and thermal compatibility between Mark II machining ceramic and Vita VM9 veneering porcelain. A bar shaped specimen (30 mm x 15 mm x 1 mm in size) of Mark II block was prepared, with 0.5 mm-deep notch (vertical to the long axis of specimen) at the middle of the bottom surface. The upper surface was veneered with 0.3 mm VM9 dentin base porcelain. Then the specimen was fractured from the notching site and the fracture surface was examined under scanning electron microscope (SEM) and electron microprobe analyzer (EMPA) with electron beam of 1 microm in diameter. Another ten specimens (30 mm x 15 mm x 1.5 mm in size) were fabricated and the temperature of thermal shock resistance were tested. SEM observation showed tight bond between these two materials and EMPA results showed penetration of Al element from Mark II block into veneering porcelain and Ca element from veneering porcelain into Mark II block occurred after sintering baking. The average temperature of thermal shock resistance for specimens in this study was (194.0+/-10.3) degrees C. Cracks were mainly distributed in veneering porcelain. Chemical bond exists between the Mark II machining ceramic and Vita VM9 veneering porcelain, and there is good thermal compatibility between them.

An algorithm for targeting finite burn maneuvers

NASA Technical Reports Server (NTRS)

Barbieri, R. W.; Wyatt, G. H.

1972-01-01

An algorithm was developed to solve the following problem: given the characteristics of the engine to be used to make a finite burn maneuver and given the desired orbit, when must the engine be ignited and what must be the orientation of the thrust vector so as to obtain the desired orbit? The desired orbit is characterized by classical elements and functions of these elements whereas the control parameters are characterized by the time to initiate the maneuver and three direction cosines which locate the thrust vector. The algorithm was built with a Monte Carlo capability whereby samples are taken from the distribution of errors associated with the estimate of the state and from the distribution of errors associated with the engine to be used to make the maneuver.

UAS Well Clear Recovery Against Non-Cooperative Intruders Using Vertical Maneuvers

NASA Technical Reports Server (NTRS)

Cone, Andrew; Thipphavong, David; Lee, Seung Man; Santiago, Confesor

2017-01-01

This paper documents a study that drove the development of a mathematical expression in the minimum operational performance standards (MOPS) of detect-and-avoid (DAA) systems for unmanned aircraft systems (UAS). This equation describes the conditions under which vertical maneuver guidance could be provided during recovery of well clear separation with a non-cooperative VFR aircraft in addition to horizontal maneuver guidance. Although suppressing vertical maneuver guidance in these situations increased the minimum horizontal separation from 500 to 800 feet, the maximum severity of loss of well clear increased in about 35 of the encounters compared to when a vertical maneuver was preferred and allowed. Additionally, analysis of individual cases led to the identification of a class of encounter where vertical rate error had a large effect on horizontal maneuvers due to the difficulty of making the correct left-right turn decision: crossing conflict with intruder changing altitude. These results supported allowing vertical maneuvers when UAS vertical performance exceeds the relative vertical position and velocity accuracy of the DAA tracker given the current velocity of the UAS and the relative vertical position and velocity estimated by the DAA tracker. Looking ahead, these results indicate a need to improve guidance algorithms by utilizing maneuver stability and near mid-air collision risk when determining maneuver guidance to regain well clear separation.

Neonatal Presentation of an Air-Filled Neck Mass that Enlarges with Valsalva: A Case Report

PubMed Central

Patel, Jasminkumar Bharatbhai; Kilbride, Howard; Paulson, Lorien

2015-01-01

Branchial cleft cysts are common causes of congenital neck masses in the pediatric population. However, neonatal presentation of branchial cleft cysts is uncommon, but recognizable secondary to acute respiratory distress from airway compression or complications secondary to infection. We report a 1-day-old infant presenting with an air-filled neck mass that enlarged with Valsalva and was not associated with respiratory distress. The infant was found to have a third branchial cleft cyst with an internal opening into the pyriform sinus. The cyst was conservatively managed with endoscopic surgical decompression and cauterization of the tract and opening. We review the embryology of branchial cleft cysts and current management. PMID:26495186

USE OF THE SDO POINTING CONTROLLERS FOR INSTRUMENT CALIBRATION MANEUVERS

NASA Technical Reports Server (NTRS)

Vess, Melissa F.; Starin, Scott R.; Morgenstern, Wendy M.

2005-01-01

During the science phase of the Solar Dynamics Observatory mission, the three science instruments require periodic instrument calibration maneuvers with a frequency of up to once per month. The command sequences for these maneuvers vary in length from a handful of steps to over 200 steps, and individual steps vary in size from 5 arcsec per step to 22.5 degrees per step. Early in the calibration maneuver development, it was determined that the original attitude sensor complement could not meet the knowledge requirements for the instrument calibration maneuvers in the event of a sensor failure. Because the mission must be single fault tolerant, an attitude determination trade study was undertaken to determine the impact of adding an additional attitude sensor versus developing alternative, potentially complex, methods of performing the maneuvers in the event of a sensor failure. To limit the impact to the science data capture budget, these instrument calibration maneuvers must be performed as quickly as possible while maintaining the tight pointing and knowledge required to obtain valid data during the calibration. To this end, the decision was made to adapt a linear pointing controller by adjusting gains and adding an attitude limiter so that it would be able to slew quickly and still achieve steady pointing once on target. During the analysis of this controller, questions arose about the stability of the controller during slewing maneuvers due to the combination of the integral gain, attitude limit, and actuator saturation. Analysis was performed and a method for disabling the integral action while slewing was incorporated to ensure stability. A high fidelity simulation is used to simulate the various instrument calibration maneuvers.

Secure VM for Monitoring Industrial Process Controllers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dasgupta, Dipankar; Ali, Mohammad Hassan; Abercrombie, Robert K

2011-01-01

In this paper, we examine the biological immune system as an autonomic system for self-protection, which has evolved over millions of years probably through extensive redesigning, testing, tuning and optimization process. The powerful information processing capabilities of the immune system, such as feature extraction, pattern recognition, learning, memory, and its distributive nature provide rich metaphors for its artificial counterpart. Our study focuses on building an autonomic defense system, using some immunological metaphors for information gathering, analyzing, decision making and launching threat and attack responses. In order to detection Stuxnet like malware, we propose to include a secure VM (or dedicatedmore » host) to the SCADA Network to monitor behavior and all software updates. This on-going research effort is not to mimic the nature but to explore and learn valuable lessons useful for self-adaptive cyber defense systems.« less

Maneuvering Rotorcraft Noise Prediction: A New Code for a New Problem

NASA Technical Reports Server (NTRS)

Brentner, Kenneth S.; Bres, Guillaume A.; Perez, Guillaume; Jones, Henry E.

2002-01-01

This paper presents the unique aspects of the development of an entirely new maneuver noise prediction code called PSU-WOPWOP. The main focus of the code is the aeroacoustic aspects of the maneuver noise problem, when the aeromechanical input data are provided (namely aircraft and blade motion, blade airloads). The PSU-WOPWOP noise prediction capability was developed for rotors in steady and transient maneuvering flight. Featuring an object-oriented design, the code allows great flexibility for complex rotor configuration and motion (including multiple rotors and full aircraft motion). The relative locations and number of hinges, flexures, and body motions can be arbitrarily specified to match the any specific rotorcraft. An analysis of algorithm efficiency is performed for maneuver noise prediction along with a description of the tradeoffs made specifically for the maneuvering noise problem. Noise predictions for the main rotor of a rotorcraft in steady descent, transient (arrested) descent, hover and a mild "pop-up" maneuver are demonstrated.

Reducing Formation-Keeping Maneuver Costs for Formation Flying Satellites in Low-Earth Orbit

NASA Technical Reports Server (NTRS)

Hamilton, Nicholas

2001-01-01

Several techniques are used to synthesize the formation-keeping control law for a three-satellite formation in low-earth orbit. The objective is to minimize maneuver cost and position tracking error. Initial reductions are found for a one-satellite case by tuning the state-weighting matrix within the linear-quadratic-Gaussian framework. Further savings come from adjusting the maneuver interval. Scenarios examined include cases with and without process noise. These results are then applied to a three-satellite formation. For both the one-satellite and three-satellite cases, increasing the maneuver interval yields a decrease in maneuver cost and an increase in position tracking error. A maneuver interval of 8-10 minutes provides a good trade-off between maneuver cost and position tracking error. An analysis of the closed-loop poles with respect to varying maneuver intervals explains the effectiveness of the chosen maneuver interval.

Maneuver Analysis and Targeting Strategy for the Stardust Re-Entry Capsule

NASA Technical Reports Server (NTRS)

Helfrich, Clifford E.; Bhat, Ram; Kangas, Julie; Wilson, Roby; Wong, Mau; Potts, Chris; Williams, Ken

2006-01-01

Stardust employed biased maneuvers to limit turns and minimize execution errors. Biased maneuvers also addressed planetary protection and safety issues. Stardust utilized a fixed-direction burn for the final maneuver to match the prevailing attitude so no turns were needed. Performance of the final burn was calibrated in flight.

Effects of Staggering Formation Maneuvers on the Magnetospheric Multi-Scale Mission Trajectories

NASA Technical Reports Server (NTRS)

Parsay, Khashayar; Mann, Laurie

2012-01-01

Formation maneuvering for the MMS mission is accomplished by executing a two-burn transfer for each spacecraft to achieve a set of desired states. Because the same radio frequency is shared by all four spacecraft, only one spacecraft can execute a maneuver at any given time. Therefore, the maneuver execution epochs for the MMS spacecraft must be staggered. The selection of the staggered maneuver sequence has a significant effect on the propellant usage and the spacecraft close-approach profile. A method for selecting a favorable maneuver sequence is proposed and measured in terms of propellant and safety.

Cassini Orbit Trim Maneuvers at Saturn - Overview of Attitude Control Flight Operations

NASA Technical Reports Server (NTRS)

Burk, Thomas A.

2011-01-01

The Cassini spacecraft has been in orbit around Saturn since July 1, 2004. To remain on the planned trajectory which maximizes science data return, Cassini must perform orbit trim maneuvers using either its main engine or its reaction control system thrusters. Over 200 maneuvers have been executed on the spacecraft since arrival at Saturn. To improve performance and maintain spacecraft health, changes have been made in maneuver design command placement, in accelerometer scale factor, and in the pre-aim vector used to align the engine gimbal actuator prior to main engine burn ignition. These and other changes have improved maneuver performance execution errors significantly since 2004. A strategy has been developed to decide whether a main engine maneuver should be performed, or whether the maneuver can be executed using the reaction control system.

Physical metallurgy: Scientific school of the Academician V.M. Schastlivtsev

NASA Astrophysics Data System (ADS)

Tabatchikova, T. I.

2016-04-01

This paper is to honor Academician Vadim Mikhailovich Schastlivtsev, a prominent scientist in the field of metal physics and materials science. The article comprises an analysis of the topical issues of the physical metallurgy of the early 21st century and of the contribution of V.M. Schastlivtsev and of his school to the science of phase and structural transformations in steels. In 2015, Vadim Mikhailovich celebrates his 80th birthday, and this paper is timed to this honorable date. The list of his main publications is given in it.

Maneuver sequence design for the post-Jupiter leg of Pioneer Saturn

NASA Technical Reports Server (NTRS)

Frauenholz, R. B.; Brady, W. F.

1976-01-01

After passing the planet Jupiter in December 1974, Pioneer 11 is on a flight path on which it will encounter Saturn in late 1979. Following an uncorrected trajectory, the spacecraft would pass 2 million km behind Saturn. A sequence of midcourse maneuvers for modifying the Pioneer trajectory is discussed. The corrected flight path is to bring the spacecraft within 500,000 km of Saturn's satellite Titan. Attention is given to maneuver capabilities and constraints, the maneuver design concept, questions related to the selection of an interim aimpoint, and aspects of maneuver implementation.

How to Maneuver Around in Eccentricity Vector Space

NASA Technical Reports Server (NTRS)

Sweetser, Theodore H.

2010-01-01

The GRAIL mission to the Moon will be the first time that two separate robotic orbiters will be placed into formation in orbit around a body other than Earth. The need to design an efficient series of maneuvers to shape the orbits and phasing of the two orbiters after arrival presents a significant challenge to mission designers. This paper presents a simple geometric method for relating in-plane impulsive maneuvers to changes in the eccentricity vector, which determines the shape and orientation of an orbit in the orbit plane. Examples then show how such maneuvers can accommodate desired changes to other orbital elements such as period, incination, and longitude of the ascending node.

Operational Challenges In TDRS Post-Maneuver Orbit Determination

NASA Technical Reports Server (NTRS)

Laing, Jason; Myers, Jessica; Ward, Douglas; Lamb, Rivers

2015-01-01

The GSFC Flight Dynamics Facility (FDF) is responsible for daily and post maneuver orbit determination for the Tracking and Data Relay Satellite System (TDRSS). The most stringent requirement for this orbit determination is 75 meters total position accuracy (3-sigma) predicted over one day for Terra's onboard navigation system. To maintain an accurate solution onboard Terra, a solution is generated and provided by the FDF Four hours after a TDRS maneuver. A number of factors present challenges to this support, such as maneuver prediction uncertainty and potentially unreliable tracking from User satellities. Reliable support is provided by comparing an extended Kalman Filter (estimated using ODTK) against a Batch Least Squares system (estimated using GTDS).

Mars Exploration Rovers Propulsive Maneuver Design

NASA Technical Reports Server (NTRS)

Potts, Christopher L.; Raofi, Behzad; Kangas, Julie A.

2004-01-01

The Mars Exploration Rovers Spirit and Opportunity successfully landed respectively at Gusev Crater and Meridiani Planum in January 2004. The rovers are essentially robotic geologists, sent on a mission to search for evidence in the rocks and soil pertaining to the historical presence of water and the ability to possibly sustain life. In order to conduct NASA's 'follow the water' strategy on opposite sides of the planet Mars, an interplanetary journey of over 300 million miles culminated with historic navigation precision. Rigorous trajectory targeting and control was necessary to achieve the atmospheric entry requirements for the selected landing sites. The propulsive maneuver design challenge was to meet or exceed these requirements while preserving the necessary design margin to accommodate additional project concerns. Landing site flexibility was maintained for both missions after launch, and even after the first trajectory correction maneuver for Spirit. The final targeting strategy was modified to improve delivery performance and reduce risk after revealing constraining trajectory control characteristics. Flight results are examined and summarized for the six trajectory correction maneuvers that were planned for each mission.

Dramatic dilatation of the upper airway secondary to a Valsalva manoeuvre in a lateral cephalometric teleradiograph of a child

PubMed Central

Varela, M; Quiñones, D; Martínez-Pérez, D

2010-01-01

Radiographs are routinely used by orthodontists for the planning of treatment for their patients and they can, in some cases, play a decisive role in the early diagnosis of some unexpected medical or surgical disorders. This report presents the case of a substantial dilatation of the upper airway in a 10-year-old girl, which was attributed to a forced Valsalva manoeuvre. The diagnosis was confirmed upon repetition of the teleradiograph with the mouth open. PMID:21062946

A safe-repositioning maneuver for the management of benign paroxysmal positional vertigo: Gans vs. Epley maneuver; a randomized comparative clinical trial.

PubMed

Saberi, Alia; Nemati, Shadman; Sabnan, Salah; Mollahoseini, Fatemeh; Kazemnejad, Ehsan

2017-08-01

Benign paroxysmal positional vertigo (BPPV) is the most common cause of peripheral vertigo. Some repositioning maneuvers have been described for its management. The aim of this study was comparing the therapeutic effect of Epley and Gans maneuvers in BPPV. This randomized clinical trial was performed from September to December 2015. 73 patients with true vertigo diagnosed as BPPV enrolled the study. They randomly assigned in quadripartite blocks to modified Epley maneuver group (E) or Gans maneuver group (G). 1 day and 1 week after intervention, the objective and subjective responses to treatment were assessed. Statistical analysis was performed using the Chi-square test and regression model in the SPSS software version 21. Thirty patients enrolled each group with a mean age of 46.9 ± 13.4 (E group) and 46.7 ± 7.5 year (G group). 23.3 % of E group and 26.7 % of G group were men (p = 0.766). In E and G groups in the first day, subjective outcomes revealed 86.7 and 60 % rate of success (p = 0.02); and 86.7 and 56.7 % of patients exhibited objective improvement, respectively (p = 0.01). After 1 week, the subjective and objective outcomes revealed improvement among 70 % of E group and 46.7 % of G group (p = 0.067). The only complication with significant difference was cervical pain with a higher rate in E group (23.3 vs. 0.0 %, p = 0.005). These results revealed the similar long-term efficacy of Epley and Gans maneuver for the treatment of BPPV. Cervical pain was most frequent complication of Epley maneuver.

Perceived threat and avoidance maneuvers in response to cockpit traffic displays

NASA Technical Reports Server (NTRS)

Smith, J. D.; Ellis, S. R.; Lee, E. C.

1984-01-01

Airline pilots rated their perception of the danger of an air-to-air collision based on cockpit displays of traffic information while they monitored simulated departures. They selected avoidance maneuvers when necessary for separation. Most evasive maneuvers were turns rather than vertical maneuvers. Evasive maneuvers chosen for encounters with lowor moderate-collision danger were generally toward the intruding aircraft. This tendency lessened as the perceived threat level increased. In the highest threat situations, pilots turned toward the intruder only at chance levels. Intruders coming from positions in front of the pilot's ship were more frequently avoided by turns toward than when intruders approached laterally or from behind. Some of the implications of the pilot's turning-toward tendencies are discussed with respect to automatic collision avoidance systems and coordination of avoidance maneuvers of conflicting aircraft.

The effect of future time perspective on delay discounting is mediated by the gray matter volume of vmPFC.

PubMed

Guo, Yiqun; Chen, Zhiyi; Feng, Tingyong

2017-07-28

Although several previous studies have shown that individuals' attitude towards time could affect their intertemporal preference, little is known about the neural basis of the relation between time perspective (TP) and delay discounting. In the present study, we quantified the gray matter (GM) cortical volume using voxel-based morphometry (VBM) methods to investigate the effect of TP on delay discounting (DD) across two independent samples. For group 1 (102 healthy college students; 46 male; 20.40 ± 1.87 years), behavioral results showed that only Future TP was a significant predictor of DD, and higher scores on Future TP were related to lower discounting rates. Whole-brain analysis revealed that steeper discounting correlated with greater GM volume in the ventromedial prefrontal cortex (vmPFC) and ventral part of posterior cingulate cortex (vPCC). Also, GM volume of a cluster in the vmPFC was correlated with Future TP. Interestingly, there was an overlapping region in vmPFC that was correlated with both DD and Future TP. Region-of-interest analysis further indicated that the overlapping region of vmPFC played a partially mediating role in the relation between Future TP and DD in the other independent dataset (Group 2, 36 healthy college students; 14 male; 20.18±1.80 years). Taken together, our results provide a new perspective from neural basis for explaining the relation between DD and future TP. Copyright © 2017 Elsevier Ltd. All rights reserved.

Arterial blood pressure response to heavy resistance exercise.

PubMed

MacDougall, J D; Tuxen, D; Sale, D G; Moroz, J R; Sutton, J R

1985-03-01

The purpose of this study was to record the blood pressure response to heavy weight-lifting exercise in five experienced body builders. Blood pressure was directly recorded by means of a capacitance transducer connected to a catheter in the brachial artery. Intrathoracic pressure with the Valsalva maneuver was recorded as mouth pressure by having the subject maintain an open glottis while expiring against a column of Hg during the lifts. Exercises included single-arm curls, overhead presses, and both double- and single-leg presses performed to failure at 80, 90, 95, and 100% of maximum. Systolic and diastolic blood pressures rose rapidly to extremely high values during the concentric contraction phase for each lift and declined with the eccentric contraction. The greatest peak pressures occurred during the double-leg press where the mean value for the group was 320/250 mmHg, with pressures in one subject exceeding 480/350 mmHg. Peak pressures with the single-arm curl exercise reached a mean group value of 255/190 mmHg when repetitions were continued to failure. Mouth pressures of 30-50 Torr during a single maximum lift, or as subjects approached failure with a submaximal weight, indicate that a portion of the observed increase in blood pressure was caused by a Valsalva maneuver. It was concluded that when healthy young subjects perform weight-lifting exercises the mechanical compression of blood vessels combines with a potent pressor response and a Valsalva response to produce extreme elevations in blood pressure. Pressures are extreme even when exercise is performed with a relatively small muscle mass.

Effect of the sinus of valsalva on the closing motion of bileaflet prosthetic heart valves.

PubMed

Ohta, Y; Kikuta, Y; Shimooka, T; Mitamura, Y; Yuhta, T; Dohi, T

2000-04-01

Conventional bileaflet prosthetic mechanical heart valves close passively with backflow. Naturally, the valve has problems associated with closure, such as backflow, water hammer effect, and fracture of the leaflet. On the other hand, in the case of the natural aortic valve, the vortex flow in the sinus of Valsalva pushes the leaflet to close, and the valve starts the closing motion earlier than the prosthetic valve as the forward flow decelerates. This closing mechanism is thought to decrease backflow at valve closure. In this study, we propose a new bileaflet mechanical valve resembling a drawbridge in shape, and the prototype valve was designed so that the leaflet closes with the help of the vortex flow in the sinus. The test valve was made of aluminum alloy, and its closing motion was compared to that of the CarboMedics (CM) valve. Both valves were driven by a computer controlled hydraulic mock circulator and were photographed at 648 frames/s by a high speed charge-coupled device (CCD) camera. Each frame of the valve motion image was analyzed with a personal computer, and the opening angles were measured. The flow rate was set as 5.0 L/min. The system was pulsed with 70 bpm, and the systolic/diastolic ratio was 0.3. Glycerin water was used as the circulation fluid at room temperature, and polystyrene particles were used to visualize the streamline. The model of the sinus of Valsalva was made of transparent silicone rubber. As a result, high speed video analysis showed that the test valve started the closing motion 41 ms earlier than the CM valve, and streamline analysis showed that the test valve had a closing mechanism similar to the natural one with the effect of vortex flow. The structure of the test valve was thought to be effective for soft closure and could solve problems associated with closure.

Experimental Evaluation Methodology for Spacecraft Proximity Maneuvers in a Dynamic Environment

DTIC Science & Technology

2017-06-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA DISSERTATION EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY MANEUVERS IN A DYNAMIC...29, 2014 – June 16, 2017 4. TITLE AND SUBTITLE EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY MANEUVERS IN A DYNAMIC ENVIRONMENT 5...LEFT BLANK ii Approved for public release. Distribution is unlimited. EXPERIMENTAL EVALUATION METHODOLOGY FOR SPACECRAFT PROXIMITY MANEUVERS IN A

Maneuvering and control of flexible space robots

NASA Technical Reports Server (NTRS)

Meirovitch, Leonard; Lim, Seungchul

1994-01-01

This paper is concerned with a flexible space robot capable of maneuvering payloads. The robot is assumed to consist of two hinge-connected flexible arms and a rigid end-effector holding a payload; the robot is mounted on a rigid platform floating in space. The equations of motion are nonlinear and of high order. Based on the assumption that the maneuvering motions are one order of magnitude larger than the elastic vibrations, a perturbation approach permits design of controls for the two types of motion separately. The rigid-body maneuvering is carried out open loop, but the elastic motions are controlled closed loop, by means of discrete-time linear quadratic regulator theory with prescribed degree of stability. A numerical example demonstrates the approach. In the example, the controls derived by the perturbation approach are applied to the original nonlinear system and errors are found to be relatively small.

Applying Dynamical Systems Theory to Optimize Libration Point Orbit Stationkeeping Maneuvers for WIND

NASA Technical Reports Server (NTRS)

Brown, Jonathan M.; Petersen, Jeremy D.

2014-01-01

NASA's WIND mission has been operating in a large amplitude Lissajous orbit in the vicinity of the interior libration point of the Sun-Earth/Moon system since 2004. Regular stationkeeping maneuvers are required to maintain the orbit due to the instability around the collinear libration points. Historically these stationkeeping maneuvers have been performed by applying an incremental change in velocity, or (delta)v along the spacecraft-Sun vector as projected into the ecliptic plane. Previous studies have shown that the magnitude of libration point stationkeeping maneuvers can be minimized by applying the (delta)v in the direction of the local stable manifold found using dynamical systems theory. This paper presents the analysis of this new maneuver strategy which shows that the magnitude of stationkeeping maneuvers can be decreased by 5 to 25 percent, depending on the location in the orbit where the maneuver is performed. The implementation of the optimized maneuver method into operations is discussed and results are presented for the first two optimized stationkeeping maneuvers executed by WIND.

Dynamic Cerebral Autoregulation Changes during Sub-Maximal Handgrip Maneuver

PubMed Central

Nogueira, Ricardo C.; Bor-Seng-Shu, Edson; Santos, Marcelo R.; Negrão, Carlos E.; Teixeira, Manoel J.; Panerai, Ronney B.

2013-01-01

Purpose We investigated the effect of handgrip (HG) maneuver on time-varying estimates of dynamic cerebral autoregulation (CA) using the autoregressive moving average technique. Methods Twelve healthy subjects were recruited to perform HG maneuver during 3 minutes with 30% of maximum contraction force. Cerebral blood flow velocity, end-tidal CO2 pressure (PETCO2), and noninvasive arterial blood pressure (ABP) were continuously recorded during baseline, HG and recovery. Critical closing pressure (CrCP), resistance area-product (RAP), and time-varying autoregulation index (ARI) were obtained. Results PETCO2 did not show significant changes during HG maneuver. Whilst ABP increased continuously during the maneuver, to 27% above its baseline value, CBFV raised to a plateau approximately 15% above baseline. This was sustained by a parallel increase in RAP, suggestive of myogenic vasoconstriction, and a reduction in CrCP that could be associated with metabolic vasodilation. The time-varying ARI index dropped at the beginning and end of the maneuver (p<0.005), which could be related to corresponding alert reactions or to different time constants of the myogenic, metabolic and/or neurogenic mechanisms. Conclusion Changes in dynamic CA during HG suggest a complex interplay of regulatory mechanisms during static exercise that should be considered when assessing the determinants of cerebral blood flow and metabolism. PMID:23967113

Effects of the Abnormal Acceleratory Environment of Flight

DTIC Science & Technology

1974-12-01

vision Return of arteriolar pulsa- tion and temporary venous distension Visual failure is a continuum from loss of peripheral vision (grey- out) to...distance); intrathoracic pressure is increased by strong muscular expiratorv efforts against a partially closed glottis; and the contraction of...vigorous skeletal muscular tensing (Valsalva maneuver) can reduce +GZ tolerance and lead to an episode of unconsciousness at extremely low G levels

14 CFR 23.155 - Elevator control force in maneuvers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Elevator control force in maneuvers. 23.155 Section 23.155 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force...

14 CFR 23.155 - Elevator control force in maneuvers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Elevator control force in maneuvers. 23.155 Section 23.155 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force...

14 CFR 23.155 - Elevator control force in maneuvers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Elevator control force in maneuvers. 23.155 Section 23.155 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force...

14 CFR 23.155 - Elevator control force in maneuvers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Elevator control force in maneuvers. 23.155 Section 23.155 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force...

14 CFR 23.155 - Elevator control force in maneuvers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Elevator control force in maneuvers. 23.155 Section 23.155 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force...

vmPFC activation during a stressor predicts positive emotions during stress recovery

PubMed Central

Yang, Xi; Garcia, Katelyn M; Jung, Youngkyoo; Whitlow, Christopher T; McRae, Kateri; Waugh, Christian E

2018-01-01

Abstract Despite accruing evidence showing that positive emotions facilitate stress recovery, the neural basis for this effect remains unclear. To identify the underlying mechanism, we compared stress recovery for people reflecting on a stressor while in a positive emotional context with that for people in a neutral context. While blood–oxygen-level dependent data were being collected, participants (N = 43) performed a stressful anagram task, which was followed by a recovery period during which they reflected on the stressor while watching a positive or neutral video. Participants also reported positive and negative emotions throughout the task as well as retrospective thoughts about the task. Although there was no effect of experimental context on emotional recovery, we found that ventromedial prefrontal cortex (vmPFC) activation during the stressor predicted more positive emotions during recovery, which in turn predicted less negative emotions during recovery. In addition, the relationship between vmPFC activation and positive emotions during recovery was mediated by decentering—the meta-cognitive detachment of oneself from one’s feelings. In sum, successful recovery from a stressor seems to be due to activation of positive emotion-related regions during the stressor itself as well as to their downstream effects on certain cognitive forms of emotion regulation. PMID:29462404

Automatic control of the Skylab Astronaut Maneuvering Research Vehicle.

NASA Technical Reports Server (NTRS)

Murtagh, T. B.; Goodwin, M. A.; Greenlee, J. E.; Whitsett , C. E.

1973-01-01

The two automatic control modes of the Astronaut Maneuvering Research Vehicle (AMRV) are analyzed: the control moment gyro (CMG) and the rate gyro (RG). The AMRV is an autonomous maneuvering unit which translates and rotates the pilot by means of hand-controller input commands. The CMG normal operation, desaturation, and cage/lock dynamics are described in terms of a realistic AMRV mass property configuration. No propellant is used for normal operation in the CMG mode, and the maximum rotation rate is 5 deg/sec about each AMRV axis. The RG attitude maneuvering and limit cycle submode dynamic are described in terms of the same AMRV mass property configuration.

Passenger comfort during terminal-area flight maneuvers. M.S. Thesis.

NASA Technical Reports Server (NTRS)

Schoonover, W. E., Jr.

1976-01-01

A series of flight experiments was conducted to obtain passenger subjective responses to closely controlled and repeatable flight maneuvers. In 8 test flights, reactions were obtained from 30 passenger subjects to a wide range of terminal-area maneuvers, including descents, turns, decelerations, and combinations thereof. Analysis of the passenger rating variance indicated that the objective of a repeatable flight passenger environment was achieved. Multiple linear regression models developed from the test data were used to define maneuver motion boundaries for specified degrees of passenger acceptance.

Biomechanical Quantification of Mendelsohn Maneuver and Effortful Swallowing on Pharyngoesophageal Function.

PubMed

Doeltgen, Sebastian Heinrich; Ong, Ellisa; Scholten, Ingrid; Cock, Charles; Omari, Taher

2017-11-01

Objective To quantify the effects of 2 swallowing maneuvers used in dysphagia rehabilitation-the Mendelsohn maneuver and effortful swallowing-on pharyngoesophageal function with novel, objective pressure-flow analysis. Study Design Evaluation of intervention effects in a healthy control cohort. Setting A pharyngoesophageal motility research laboratory in a tertiary education facility. Subjects Twelve young healthy subjects (9 women, 28.6 ± 7.9 years) from the general public, without swallowing impairment, volunteered to participate in this study. Methods Surface electromyography from the floor-of-mouth musculature and high-resolution impedance manometry-based pressure flow analysis were used to assess floor-of-mouth activation and pharyngoesophageal motility, respectively. Subjects each performed 10 noneffortful control swallows, Mendelsohn maneuver swallows, and effortful swallows, with a 5-mL viscous bolus. Repeated measures analyses of variance was used to compare outcome measures across conditions. Results Effortful and Mendelsohn swallows generated greater floor-of-mouth contraction ( P = .001) and pharyngeal pressure ( P < .0001) when compared with control swallows. There were no changes at the level of the upper esophageal sphincter, except for a faster opening to maximal diameter during maneuver swallows ( P = .01). The proximal esophageal contractile integral was reduced during Mendelsohn swallows ( P = .001). Conclusion Effortful and Mendelsohn maneuver swallows significantly alter the pharyngoesophageal pressure profile. Faster opening of the upper esophageal sphincter may facilitate bolus transfer during maneuver swallows; however, reduced proximal esophageal contractility during Mendelsohn maneuver swallows may impair bolus flow and aggravate dysphagic symptoms.

46 CFR 35.20-40 - Maneuvering characteristics-T/OC.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Maneuvering characteristics-T/OC. 35.20-40 Section 35.20-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-40 Maneuvering characteristics—T/OC. For each ocean and coastwise tankship of 1,600 gross tons or...

oVEMP as an objective indicator of successful repositioning maneuver.

PubMed

Asal, Samir; Sobhy, Osama; Balbaa, Amany

Benign paroxysmal positioning vertigo (BPPV) is the most common peripheral vestibular disorder. Canalolithiasis in the posterior semi-circular canal is the most common underlying pathology that can be treated effectively by repositioning maneuvers. Our hypothesis suggested that successful maneuvers can lead to repositioning of dislodged otoconia to the utricle. Air conducted oVEMP, which is thought to originate from the contra-lateral utricular organ was measured in twenty patients with unilateral BPPV and we compared n1-p1 peak to peak amplitude of the affected ears in 3 separate intervals: on pre-treatment when typical nystagmus was confirmed, immediately after, and 1 week after repositioning maneuvers to assess change, if any, in amplitude. This study showed significant increase of oVEMP amplitude in the affected ears after successful repositioning maneuver that was more significant after 1 week. oVEMP can be used as a reliable objective test for ensuring a successful maneuver rather than subjective dependence on the patient's symptoms, which may be misleading due to a remission. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

The Art and Science of Operational Maneuver,

DTIC Science & Technology

1988-05-04

Classification) The Art and Science of Operational Maneuver (U) 12. PERSONAL AUTHOR(S) MAJ Joseph Schroedel 13a. TYPE OF REPORT 13b. TIME COVERED 14...CLASSIFICATION OF THIS PAGE VA) CL LA S F1 EP {fJE ART ANQ SCIENCE OlF OPERAIl NAL MANUVER By6 Mal or Josepi~ Schroeci, L U. S. Arm~y H Aciv -darILC Ced M ili t...Studies ,nIgz’raph ApprovwA. Name of Student: Major Jonevh Schroedel. U.S. Army Title ot Monograph: The Art and Science of Operational Maneuver Approved By

Effect of perceived threat on avoidance maneuvers selected while viewing cockpit traffic displays

NASA Technical Reports Server (NTRS)

Smith, J. D.; Ellis, S. R.

1982-01-01

Ten airline pilots rated the collision danger of air traffic presented on cockpit displays of traffic information (CDTI) while they monitored simulated departures from Denver. They selected avoidance maneuvers when necessary for separation. Most evasive maneuvers were turns rather than vertical maneuvers. Evasive maneuvers chosen for encounters with low or moderate perceived collision danger were generally toward the intruding aircraft. This tendency lessened as the perceived threat level increased. In the highest threat situations pilots turned toward the intruder only at chance levels. Some of the implications of the pilots' turning-towards tendencies are discussed with respect to automatic collision avoidance systems and coordination of avoidance maneuvers of conflicting aircraft.

Time frequency analysis of sound from a maneuvering rotorcraft

NASA Astrophysics Data System (ADS)

Stephenson, James H.; Tinney, Charles E.; Greenwood, Eric; Watts, Michael E.

2014-10-01

The acoustic signatures produced by a full-scale, Bell 430 helicopter during steady-level-flight and transient roll-right maneuvers are analyzed by way of time-frequency analysis. The roll-right maneuvers comprise both a medium and a fast roll rate. Data are acquired using a single ground based microphone that are analyzed by way of the Morlet wavelet transform to extract the spectral properties and sound pressure levels as functions of time. The findings show that during maneuvering operations of the helicopter, both the overall sound pressure level and the blade-vortex interaction sound pressure level are greatest when the roll rate of the vehicle is at its maximum. The reduced inflow in the region of the rotor disk where blade-vortex interaction noise originates is determined to be the cause of the increase in noise. A local decrease in inflow reduces the miss distance of the tip vortex and thereby increases the BVI noise signature. Blade loading and advance ratios are also investigated as possible mechanisms for increased sound production, but are shown to be fairly constant throughout the maneuvers.

Maneuver Recovery Analysis for the Magnetospheric Multiscale Mission

NASA Technical Reports Server (NTRS)

Gramling, Cheryl; Carpenter, Russell; Volle, Michael; Lee, Taesul; Long, Anne

2007-01-01

The use of spacecraft formations creates new and more demanding requirements for orbit determination accuracy. In addition to absolute navigation requirements, there are typically relative navigation requirements that are based on the size or shape of the formation. The difficulty in meeting these requirements is related to the relative dynamics of the spacecraft orbits and the frequency of the formation maintenance maneuvers. This paper examines the effects of bi-weekly formation maintenance maneuvers on the absolute and relative orbit determination accuracy for the four-spacecraft Magnetospheric Multiscale (MMS) formation. Results are presented from high fidelity simulations that include the effects of realistic orbit determination errors in the maneuver planning process. Solutions are determined using a high accuracy extended Kalman filter designed for onboard navigation. Three different solutions are examined, considering the effects of process noise and measurement rate on the solutions.

Evaluating the Tongue-Hold Maneuver Using High-Resolution Manometry and Electromyography

PubMed Central

Hammer, Michael J.; Jones, Corinne A.; Mielens, Jason D.; Kim, Chloe H.; McCulloch, Timothy M.

2014-01-01

The tongue-hold maneuver is a widely used clinical technique designed to increase posterior pharyngeal wall movement in individuals with dysphagia. It is hypothesized that the tongue-hold maneuver results in increased contraction of the superior pharyngeal constrictor. However, an electromyographic study of the pharynx and tongue during the tongue-hold is still needed to understand whether and how swallow muscle activity and pressure may change with this maneuver. We tested eight healthy young participants using simultaneous intramuscular electromyography with high-resolution manometry during three task conditions including (a) saliva swallow without maneuver, (b) saliva swallow with the tongue tip at the lip, and (c) saliva swallow during the tongue-hold maneuver. We tested the hypothesis that tongue and pharyngeal muscle activity would increase during the experimental tasks, but that pharyngeal pressure would remain relatively unchanged. We found that the pre-swallow magnitude of tongue, pharyngeal constrictor, and cricopharyngeus muscle activity increased. During the swallow, the magnitude and duration of tongue and pharyngeal constrictor muscle activity each increased. However, manometric pressures and durations remained unchanged. These results suggest that increased superior pharyngeal constrictor activity may serve to maintain relatively stable pharyngeal pressures in the absence of posterior tongue movement. Thus, the tongue-hold maneuver may be a relatively simple but robust example of how the medullary swallow center is equipped to dynamically coordinate actions between tongue and pharynx. Our findings emphasize the need for combined modality swallow assessment to include high-resolution manometry and intramuscular electromyography to evaluate the potential benefit of the tongue-hold maneuver for clinical populations. PMID:24969727

Nonlinear maneuver autopilot for the F-15 aircraft

NASA Technical Reports Server (NTRS)

Menon, P. K. A.; Badgett, M. E.; Walker, R. A.

1989-01-01

A methodology is described for the development of flight test trajectory control laws based on singular perturbation methodology and nonlinear dynamic modeling. The control design methodology is applied to a detailed nonlinear six degree-of-freedom simulation of the F-15 and results for a level accelerations, pushover/pullup maneuver, zoom and pushover maneuver, excess thrust windup turn, constant thrust windup turn, and a constant dynamic pressure/constant load factor trajectory are presented.

Associating crash avoidance maneuvers with driver attributes and accident characteristics: a mixed logit model approach.

PubMed

Kaplan, Sigal; Prato, Carlo Giacomo

2012-01-01

The current study focuses on the propensity of drivers to engage in crash avoidance maneuvers in relation to driver attributes, critical events, crash characteristics, vehicles involved, road characteristics, and environmental conditions. The importance of avoidance maneuvers derives from the key role of proactive and state-aware road users within the concept of sustainable safety systems, as well as from the key role of effective corrective maneuvers in the success of automated in-vehicle warning and driver assistance systems. The analysis is conducted by means of a mixed logit model that represents the selection among 5 emergency lateral and speed control maneuvers (i.e., "no avoidance maneuvers," "braking," "steering," "braking and steering," and "other maneuvers) while accommodating correlations across maneuvers and heteroscedasticity. Data for the analysis were retrieved from the General Estimates System (GES) crash database for the year 2009 by considering drivers for which crash avoidance maneuvers are known. The results show that (1) the nature of the critical event that made the crash imminent greatly influences the choice of crash avoidance maneuvers, (2) women and elderly have a relatively lower propensity to conduct crash avoidance maneuvers, (3) drowsiness and fatigue have a greater negative marginal effect on the tendency to engage in crash avoidance maneuvers than alcohol and drug consumption, (4) difficult road conditions increase the propensity to perform crash avoidance maneuvers, and (5) visual obstruction and artificial illumination decrease the probability to carry out crash avoidance maneuvers. The results emphasize the need for public awareness campaigns to promote safe driving style for senior drivers and warning about the risks of driving under fatigue and distraction being comparable to the risks of driving under the influence of alcohol and drugs. Moreover, the results suggest the need to educate drivers about hazard perception, designing

An Optimized Method to Detect BDS Satellites' Orbit Maneuvering and Anomalies in Real-Time.

PubMed

Huang, Guanwen; Qin, Zhiwei; Zhang, Qin; Wang, Le; Yan, Xingyuan; Wang, Xiaolei

2018-02-28

The orbital maneuvers of Global Navigation Satellite System (GNSS) Constellations will decrease the performance and accuracy of positioning, navigation, and timing (PNT). Because satellites in the Chinese BeiDou Navigation Satellite System (BDS) are in Geostationary Orbit (GEO) and Inclined Geosynchronous Orbit (IGSO), maneuvers occur more frequently. Also, the precise start moment of the BDS satellites' orbit maneuvering cannot be obtained by common users. This paper presented an improved real-time detecting method for BDS satellites' orbit maneuvering and anomalies with higher timeliness and higher accuracy. The main contributions to this improvement are as follows: (1) instead of the previous two-steps method, a new one-step method with higher accuracy is proposed to determine the start moment and the pseudo random noise code (PRN) of the satellite orbit maneuvering in that time; (2) BDS Medium Earth Orbit (MEO) orbital maneuvers are firstly detected according to the proposed selection strategy for the stations; and (3) the classified non-maneuvering anomalies are detected by a new median robust method using the weak anomaly detection factor and the strong anomaly detection factor. The data from the Multi-GNSS Experiment (MGEX) in 2017 was used for experimental analysis. The experimental results and analysis showed that the start moment of orbital maneuvers and the period of non-maneuver anomalies can be determined more accurately in real-time. When orbital maneuvers and anomalies occur, the proposed method improved the data utilization for 91 and 95 min in 2017.

An Optimized Method to Detect BDS Satellites’ Orbit Maneuvering and Anomalies in Real-Time

PubMed Central

Huang, Guanwen; Qin, Zhiwei; Zhang, Qin; Wang, Le; Yan, Xingyuan; Wang, Xiaolei

2018-01-01

The orbital maneuvers of Global Navigation Satellite System (GNSS) Constellations will decrease the performance and accuracy of positioning, navigation, and timing (PNT). Because satellites in the Chinese BeiDou Navigation Satellite System (BDS) are in Geostationary Orbit (GEO) and Inclined Geosynchronous Orbit (IGSO), maneuvers occur more frequently. Also, the precise start moment of the BDS satellites’ orbit maneuvering cannot be obtained by common users. This paper presented an improved real-time detecting method for BDS satellites’ orbit maneuvering and anomalies with higher timeliness and higher accuracy. The main contributions to this improvement are as follows: (1) instead of the previous two-steps method, a new one-step method with higher accuracy is proposed to determine the start moment and the pseudo random noise code (PRN) of the satellite orbit maneuvering in that time; (2) BDS Medium Earth Orbit (MEO) orbital maneuvers are firstly detected according to the proposed selection strategy for the stations; and (3) the classified non-maneuvering anomalies are detected by a new median robust method using the weak anomaly detection factor and the strong anomaly detection factor. The data from the Multi-GNSS Experiment (MGEX) in 2017 was used for experimental analysis. The experimental results and analysis showed that the start moment of orbital maneuvers and the period of non-maneuver anomalies can be determined more accurately in real-time. When orbital maneuvers and anomalies occur, the proposed method improved the data utilization for 91 and 95 min in 2017. PMID:29495638

Analysis of aircraft performance during lateral maneuvering for microburst avoidance

NASA Technical Reports Server (NTRS)

Avila De Melo, Denise; Hansman, R. John, Jr.

1990-01-01

Aircraft response to a severe and a moderate three-dimensional microburst model using nonlinear numerical simulations of a Boeing 737-100 is studied. The relative performance loss is compared for microburst escape procedures with and without lateral maneuvering. The results show that the hazards caused by the penetration of a microburst in the landing phase are attenuated if lateral escape maneuvers are applied in order to turn the aircraft away from the microburst core rather than flying straight through. If the lateral escape maneuver is initiated close to the microburst core, high bank angles tend to deteriorate aircraft performance. Lateral maneuvering is also found to reduce the advanced warning required to escape from microburst hazards but requires that information of the existence and location of the microburst is available (i.e., remote detection) in order to avoid an incorrect turn toward the microburst core.

Local structures of the tetragonal Gd3 -VM and Gd3 -Li centers in perovskite fluorides

NASA Astrophysics Data System (ADS)

Zheng, W. C.

The zero-field splittings b20 of the tetragonal Gd3+-VM and Gd3+-Li+ centers for Gd3+ ions in fluoroperovskite crystals have been studied on the basis of the superposition model in which the value of t2

Development of a completely autologous valved conduit with the sinus of Valsalva using in-body tissue architecture technology: a pilot study in pulmonary valve replacement in a beagle model.

PubMed

Yamanami, Masashi; Yahata, Yuki; Uechi, Masami; Fujiwara, Megumi; Ishibashi-Ueda, Hatsue; Kanda, Keiichi; Watanabe, Taiji; Tajikawa, Tsutomu; Ohba, Kenkichi; Yaku, Hitoshi; Nakayama, Yasuhide

2010-09-14

We developed autologous prosthetic implants by simple and safe in-body tissue architecture technology. We present the first report on the development of autologous valved conduit with the sinus of Valsalva (BIOVALVE) by using this unique technology and its subsequent implantation in the pulmonary valves in a beagle model. A mold of BIOVALVE organization was assembled using 2 types of specially designed silicone rods with a small aperture in a trileaflet shape between them. The concave rods had 3 projections that resembled the protrusions of the sinus of Valsalva. The molds were placed in the dorsal subcutaneous spaces of beagle dogs for 4 weeks. The molds were covered with autologous connective tissues. BIOVALVEs with 3 leaflets in the inner side of the conduit with the sinus of Valsalva were obtained after removing the molds. These valves had adequate burst strength, similar to that of native valves. Tight valvular coaptation and sufficient open orifice area were observed in vitro. These BIOVALVEs were implanted to the main pulmonary arteries as allogenic conduit valves (n=3). Postoperative echocardiography demonstrated smooth movement of the leaflets with trivial regurgitation. Histological examination of specimens obtained at 84 days showed that the surface of the leaflet was covered by endothelial cells and neointima, including an elastin fiber network, and was formed at the anastomosis sides on the luminal surface of the conduit. We developed the first completely autologous BIOVALVE and successfully implanted these BIOVALVEs in a beagle model in a pilot study.

Pneumopericardium and pneumomediastinum in a passenger on a commercial flight.

PubMed

Nicol, Edward; Davies, Gary; Jayakumar, Prakash; Green, Nicholas D C

2007-04-01

Pneumopericardium and pneumomediastinum are rare presentations seen most commonly in the context of chest trauma or mechanical ventilation. Here we present a case of a spontaneous pneumopericardium and pneumomediastinum, which occurred in a young man with a recent coryzal illness and multiple Valsalva maneuvers in flight. Although the etiology of pneumopericardium and pneumomediastinum are well described in the literature, possible acute risks to flight personnel have not been previously documented.

Orbit determination and prediction of GEO satellite of BeiDou during repositioning maneuver

NASA Astrophysics Data System (ADS)

Cao, Fen; Yang, XuHai; Li, ZhiGang; Sun, BaoQi; Kong, Yao; Chen, Liang; Feng, Chugang

2014-11-01

In order to establish a continuous GEO satellite orbit during repositioning maneuvers, a suitable maneuver force model has been established associated with an optimal orbit determination method and strategy. A continuous increasing acceleration is established by constructing a constant force that is equivalent to the pulse force, with the mass of the satellite decreasing throughout maneuver. This acceleration can be added to other accelerations, such as solar radiation, to obtain the continuous acceleration of the satellite. The orbit determination method and strategy are illuminated, with subsequent assessment of the orbit being determined and predicted accordingly. The orbit of the GEO satellite during repositioning maneuver can be determined and predicted by using C-Band pseudo-range observations of the BeiDou GEO satellite with COSPAR ID 2010-001A in 2011 and 2012. The results indicate that observations before maneuver do affect orbit determination and prediction, and should therefore be selected appropriately. A more precise orbit and prediction can be obtained compared to common short arc methods when observations starting 1 day prior the maneuver and 2 h after the maneuver are adopted in POD (Precise Orbit Determination). The achieved URE (User Range Error) under non-consideration of satellite clock errors is better than 2 m within the first 2 h after maneuver, and less than 3 m for further 2 h of orbit prediction.

Prediction of jump phenomena in roll-coupled maneuvers of airplanes

NASA Technical Reports Server (NTRS)

Schy, A. A.; Hannah, M. E.

1976-01-01

An easily computerized analytical method is developed for identifying critical airplane maneuvers in which nonlinear rotational coupling effects may cause sudden jumps in the response to pilot's control inputs. Fifth and ninth degree polynomials for predicting multiple pseudo-steady states of roll-coupled maneuvers are derived. The program calculates the pseudo-steady solutions and their stability. The occurrence of jump-like responses for several airplanes and a variety of maneuvers is shown to correlate well with the appearance of multiple stable solutions for critical control combinations. The analysis is extended to include aerodynamics nonlinear in angle of attack.

Constellation Mission Operation Working Group: ESMO Maneuver Planning Process Review

NASA Technical Reports Server (NTRS)

Moyer, Eric

2015-01-01

The Earth Science Mission Operation (ESMO) Project created an Independent Review Board to review our Conjunction Risk evaluation process and Maneuver Planning Process to identify improvements that safely manages mission conjunction risks, maintains ground track science requirements, and minimizes overall hours expended on High Interest Events (HIE). The Review Board is evaluating the current maneuver process which requires support by multiple groups. In the past year, there have been several changes to the processes although many prior and new concerns exist. This presentation will discuss maneuver process reviews and Board comments, ESMO assessment and path foward, ESMO future plans, recent changes and concerns.

Pringle's Maneuver With a Releasable Insulok Band.

PubMed

Chang, Yu-Chung

2015-10-01

Currently, there are many conventional instruments being applied to perform hepatic inflow control, the Pringle's maneuver, distal to the hepatic hilum during hepatic resections. We wondered if a commonly used Insulok band can be added. Insulok band is a plastic tying device molded in one piece with an excellent cam-lock mechanism. We have applied releasable Insulok band to the Pringle's maneuver in 10 partial hepatectomy cases, which are not suitable for application of Chang's needle. After opening the lesser omentum, the band was passed through the Winslow foramen to the lesser sac, and the portal triad was occluded by locking the band. During the intermittent reperfusion period, this Insulok band allowed easy and fast control of hepatic inflow with its simple releasable locking device. Single inflow block was used on 6 cases while repeated block on 4 cases for partial hepatectomy. The average ischemic time was 15.2 ± 8.2 minutes with an interval of 5 minutes. There was neither procedure-related morbidity nor mortality. No patient had developed postoperative hepatic failure or prolonged liver dysfunction. The efficacy of bleeding control was excellent and the average blood loss during Pringle's maneuver was 6 ± 12.6 mL. Furthermore, locking and unlocking of the Insulok band each took only 5 seconds. Releasable Insulok band is a simpler, faster, cheaper, and safe alternative to the conventional methods for blocking hepatic inflow in Pringle's maneuver, especially in those cases not suitable for using the Chang's needle. © The Author(s) 2014.

Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

NASA Technical Reports Server (NTRS)

1973-01-01

Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the foreward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). This ASMU exerperiment is being done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

NASA Technical Reports Server (NTRS)

1973-01-01

Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the forward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). This ASMU exerperiment is being done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

An interplanetary targeting and orbit insertion maneuver design technique

NASA Technical Reports Server (NTRS)

Hintz, G. R.

1980-01-01

The paper describes a tradeoff in selecting a planetary encounter aimpoint and a spacecraft propulsive maneuver strategy in the Pioneer Venus Orbiter Mission. The method uses parametric data spanning a region of acceptable targeting aimpoints in the delivery space and the geometric considerations. Real-time maneuver adjustments accounted for known attitude control errors, orbit determination updates, and late changes in a targeting specification.

Biomechanical study on the bladder neck and urethral positions: simulation of impairment of the pelvic ligaments.

PubMed

Brandão, Sofia; Parente, Marco; Mascarenhas, Teresa; da Silva, Ana Rita Gomes; Ramos, Isabel; Jorge, Renato Natal

2015-01-21

Excessive mobility of the bladder neck and urethra are common features in stress urinary incontinence. We aimed at assessing, through computational modelling, the bladder neck position taking into account progressive impairment of the pelvic ligaments. Magnetic resonance images of a young healthy female were used to build a computational model of the pelvic cavity. Appropriate material properties and constitutive models were defined. The impairment of the ligaments was simulated by mimicking a reduction in their stiffness. For healthy ligaments, valsalva maneuver led to an increase in the α angle (between the bladder neck-symphysis pubis and the main of the symphysis) from 91.8° (at rest) to 105.7°, and 5.7 mm of bladder neck dislocation, which was similar to dynamic imaging of the same woman (α angle from 80° to 103.3°, and 5mm of bladder neck movement). For 95% impairment, they enlarged to 124.28° and 12 mm. Impairment to the pubourethral ligaments had higher effect than that of vaginal support (115° vs. 108°, and 9.1 vs. 7.3mm). Numerical simulation could predict urethral motion during valsalva maneuver, for both healthy and impaired ligaments. Results were similar to those of continent women and women with stress urinary incontinence published in the literature. Biomechanical analysis of the pubourethral ligaments complements the biomechanical study of the pelvic cavity in urinary incontinence. It may be useful in young women presenting stress urinary incontinence without imaging evidence of urethral and muscle lesions or organ descend during valsalva, and for whom fascial damage are not expected. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mars Science Laboratory Cruise Propulsion Maneuvering Operations

NASA Technical Reports Server (NTRS)

Baker, Raymond S.; Mizukami, Masahi; Barber, Todd J.

2013-01-01

Mars Science Laboratory "Curiosity" is NASA's most recent mission to Mars, launched in November 2011, and landed in August 2012. It is a subcompact car-sized nuclear powered rover designed for a long duration mission, with an extensive suite of science instruments. Entry, descent and landing used a unique "skycrane" concept. This report describes the propulsive maneuvering operations during cruise from Earth to Mars, to control attitudes and to target the vehicle for entry. The propulsion subsystem, mission operations, and flight performance are discussed. All trajectory control maneuvers were well within accuracy requirements, and all turns and spin corrections were nominal.

Hypersonic maneuvering to provide planetary gravity assist

NASA Technical Reports Server (NTRS)

Mcronald, Angus D.; Randolph, James E.

1990-01-01

This paper examines the potential of aeroassist maneuvers at Mars for missions to the sun and to Pluto, using a high-lift/drag vehicle such as the waverider to perform an atmospheric 'fly-around' of Mars, in order to rotate the planetocentric velocity vector, thus adding to the rather small rotation due to gravity alone. A fly-around in one direction or the other can place the aphelion or the perihelion of the resulting orbit at the Mars distance, for missions toward the sun or toward Pluto, respectively. The parameters of such maneuvers are given as a function of earth launch velocity.

Cassini Solstice Mission Maneuver Experience: Year Two

NASA Technical Reports Server (NTRS)

Arrieta, Juan; Ballard, Christopher G.; Hahn, Yungsun

2012-01-01

The Cassini Spacecraft was launched in October 1997 on a mission to observe Saturn and its moons; it entered orbit around Saturn in July 2004 for a nominal four-year Prime Mission, later augmented by two extensions: the Equinox Mission, from July 2008 through September 2010, and the Solstice Mission, from October 2010 through September 2017. This paper provides an overview of the maneuver activities from August 2011 through June 2012 which include the design of 38 Orbit Trim Maneuvers--OTM-288 through OTM-326-- for attaining 14 natural satellite encounters: seven with Titan, six with Enceladus, and one with Dione.

Attitude maneuvers of a solar-powered electric orbital transfer vehicle

NASA Astrophysics Data System (ADS)

Jenkin, Alan B.

1992-08-01

Attitude maneuver requirements of a solar-powered electric orbital transfer vehicle have been studied in detail. This involved evaluation of the yaw, pitch, and roll profiles and associated angular accelerations needed to simultaneously steer the vehicle thrust vector and maintain the solar array pointed toward the sun. Maintaining the solar array pointed exactly at the sun leads to snap roll maneuvers which have very high (theoretically unbounded) accelerations, thereby imposing large torque requirements. The problem is exacerbated by the large solar arrays which are needed to generate the high levels of power needed by electric propulsion devices. A method of eliminating the snap roll maneuvers is presented. The method involves the determination of relaxed roll profiles which approximate a forced transition between alternate exact roll profiles and incur only small errors in solar array pointing. The method makes it feasible to perform the required maneuvers using currently available attitude control technology such as reaction wheels, hot gas jets, or gimballed main engines.

Global Optimization of N-Maneuver, High-Thrust Trajectories Using Direct Multiple Shooting

NASA Technical Reports Server (NTRS)

Vavrina, Matthew A.; Englander, Jacob A.; Ellison, Donald H.

2016-01-01

The performance of impulsive, gravity-assist trajectories often improves with the inclusion of one or more maneuvers between flybys. However, grid-based scans over the entire design space can become computationally intractable for even one deep-space maneuver, and few global search routines are capable of an arbitrary number of maneuvers. To address this difficulty a trajectory transcription allowing for any number of maneuvers is developed within a multi-objective, global optimization framework for constrained, multiple gravity-assist trajectories. The formulation exploits a robust shooting scheme and analytic derivatives for computational efficiency. The approach is applied to several complex, interplanetary problems, achieving notable performance without a user-supplied initial guess.

Development of a Smooth Trajectory Maneuver Method to Accommodate the Ares I Flight Control Constraints

NASA Technical Reports Server (NTRS)

Pinson, Robin M.; Schmitt, Terri L.; Hanson, John M.

2008-01-01

Six degree-of-freedom (DOF) launch vehicle trajectories are designed to follow an optimized 3-DOF reference trajectory. A vehicle has a finite amount of control power that it can allocate to performing maneuvers. Therefore, the 3-DOF trajectory must be designed to refrain from using 100% of the allowable control capability to perform maneuvers, saving control power for handling off-nominal conditions, wind gusts and other perturbations. During the Ares I trajectory analysis, two maneuvers were found to be hard for the control system to implement; a roll maneuver prior to the gravity turn and an angle of attack maneuver immediately after the J-2X engine start-up. It was decided to develop an approach for creating smooth maneuvers in the optimized reference trajectories that accounts for the thrust available from the engines. A feature of this method is that no additional angular velocity in the direction of the maneuver has been added to the vehicle after the maneuver completion. This paper discusses the equations behind these new maneuvers and their implementation into the Ares I trajectory design cycle. Also discussed is a possible extension to adjusting closed-loop guidance.

Study of the Characteristics of Pulmonary Trunk in Pulmonary Hypertension Secondary to Left Heart Disease Using Pressure-Velocity Loops (PU-Loops).

PubMed

Hanya, Shizuo; Yoshii, Kengo; Sugawara, Motoaki

2017-09-25

Objectives : Although pulmonary hypertension (PH) caused by left heart disease (PH-LHD) is more common in PH, little is known about its properties of pulmonary artery (PA) in PH-LHD. The purpose of this study was to measure pulmonary regional pulse wave velocity (PWV) and to quantify the magnitude of reflected waves in patients with PH-LHD by the analysis of the pressure-velocity loops (PU-loop). Methods : High-fidelity PA pressure (Pm) and PA velocity (Vm) were measured in 11 subjects with PH-LHD (mean Pm>25 mmHg), 1 subject with atrial septal defect (ASD) without PH and 12 control subjects, using multisensor catheters. PWV was calculated as the slope of the initial part of the PU-loop in early systole. The similarity in the shapes of the pressure and flow velocity waveforms over one PU-loop was quantified as the magnitude of reflected wave by calculating the standard error of the estimate (Sy/x) from linear regression analysis between Pm and corresponding Vm. PWV and Sy/x during a Valsalva maneuver (VM) were also assessed in nine control subjects. Results : The contour of PU-loop was so characteristic between control and PH-LHD. Max. PWV (349 cm/s) was recorded in PH-LHD and min. PWV (111 cm/s) was recorded in ASD. VM increased Pm (12 [7-15] mmHg vs. 50 [18-110] mmHg; p=0.009) and PWV (200 [148-238] cm/s vs. 260 [192-306] cm/s; p=0.009) significantly without significant increase of Sy/x (19.6 [12.7-28.9]% vs. 28.2 [19.3-40.7]%; p=0.079). Although Sy/x was significantly higher in PH-LHD than in control and ASD (31.0 [14.3-36.3]% vs. 17.5 [8.4-28.9]%; p=0.009, ASD: 18.2%) , no significant difference was found in PWV between PH-LHD and control (269 [159-349] cm/s vs. 203 [154-289] cm/s; p=0.089). Conclusions : 1) The magnitude of wave reflection was elevated in PH-LHD significantly as compared with control and ASD. 2) Despite the significant increase in PA-PWV caused by abrupt elevation in Pm during VM in control, chronic elevation in Pm did not increase PA

Heimlich's maneuver-assisted bronchoscopic removal of airway foreign body

PubMed Central

Solanki, Sohan Lal; Bansal, Shivendu; Khare, Arvind; Jain, Amit

2011-01-01

Aspiration of foreign bodies (FBs) by children can lead to serious illness and sometimes even death. Bronchoscopic removal of the FB is necessary to prevent from any catastrophic event. Sometimes bronchoscopic removal is not possible due to the larger size of the FB, sharp FB, or long duration FB. Tracheostomy is normally used for the removal of such FBs. The aim of this case report is to highlight the use of Heimlich maneuver for the removal of such FBs before opting invasive procedures. In the present case, a 5-year-old child was presented with history of FB aspiration 5 h back. After multiple failed bronchoscopic attempts to remove the FB it was decided to use Heimlich maneuver in the supine position. A single attempt of Heimlich maneuver expelled the FB into the oral cavity, which was removed by Magill's forceps. On repeated bronchoscope check, there was no remnant of FB. Child's further course of stay in hospital was uneventful. In conclusion, Heimlich maneuver may be useful in patient with failed bronchoscope removal of airway FBs before proceeding for tracheotomy or other invasive procedures. PMID:25885389

Intermediate Maneuver Induced Rollover Simulation (IMIRS) and Sensitivity Analysis. Final Report

DOT National Transportation Integrated Search

1991-02-01

This report describes the development of the Intermediate Maneuver Induced Rollover Simulation (IMIRS) which can be used to investigate the phenomenon of maneuver induced rollover of light vehicles. The IMIRS represents an enhancement of the existing...

Picking the Right Horse? Dominant Maneuver in the Twenty-First Century

DTIC Science & Technology

1998-06-05

SUBTITLE Picking the Right Horse ? Dominant Maneuver in the Twenty-First Century 6.AUTH0RIS) Major Steven D. Russell, U.S. Army 7. PERFORMING...Z39-18 298-102 PICKING THE RIGHT HORSE ? DOMINANT MANEUVER IN THE TWENTY-FIRST CENTURY A thesis presented to the Faculty of the U.S. Army Command...unlimited. wc«’*u»»»«aBI PICKING THE RIGHT HORSE ? DOMINANT MANEUVER IN THE TWENTY-FIRST CENTURY A thesis presented to the Faculty of the U.S. Army

Early Mission Maneuver Operations for the Deep Space Climate Observatory

NASA Technical Reports Server (NTRS)

Roberts, Craig; Case, Sara; Reagoso, John

2015-01-01

DSCOVR Lissajous Orbit sized such that orbit track never extends beyond 15 degrees from Earth-Sun line (as seen from Earth). Requiring delta-V maneuvers, control orbit to obey a Solar Exclusion Zone (SEZ) cone of half-angle 4 degrees about the Earth-Sun line. Spacecraft should never be less than 4 degrees from solar center as seen from Earth. Following Lissajous Orbit Insertion (LOI), DSCOVR should be in an opening phase that just skirts the 4-degree SEZ. Maximizes time to the point where a closing Lissajous will require avoidance maneuvers to keep it out of the SEZ. Station keeping maneuvers should take no more than 15 minutes

Fuel optimal maneuvers for spacecraft with fixed thrusters

NASA Technical Reports Server (NTRS)

Carter, T. C.

1982-01-01

Several mathematical models, including a minimum integral square criterion problem, were used for the qualitative investigation of fuel optimal maneuvers for spacecraft with fixed thrusters. The solutions consist of intervals of "full thrust" and "coast" indicating that thrusters do not need to be designed as "throttleable" for fuel optimal performance. For the primary model considered, singular solutions occur only if the optimal solution is "pure translation". "Time optimal" singular solutions can be found which consist of intervals of "coast" and "full thrust". The shape of the optimal fuel consumption curve as a function of flight time was found to depend on whether or not the initial state is in the region admitting singular solutions. Comparisons of fuel optimal maneuvers in deep space with those relative to a point in circular orbit indicate that qualitative differences in the solutions can occur. Computation of fuel consumption for certain "pure translation" cases indicates that considerable savings in fuel can result from the fuel optimal maneuvers.

Alter spontaneous activity in amygdala and vmPFC during fear consolidation following 24 h sleep deprivation.

PubMed

Feng, Pan; Becker, Benjamin; Feng, Tingyong; Zheng, Yong

2018-05-15

Sleep deprivation (SD) has been associated with cognitive and emotional disruptions, however its impact on the acquisition of fear and subsequent fear memory consolidation remain unknown. To address this question, we measured human brain activity before and after fear acquisition under conditions of 24 h sleep deprivation versus normal sleep using resting-state functional magnetic resonance imaging (rs-fMRI). Additionally, we explored whether the fear acquisition-induced change of brain activity during the fear memory consolidation window can be predicted by subjective fear ratings and autonomic fear response, assessed by skin conductance responses (SCR) during acquisition. Behaviorally, the SD group demonstrated increased subjective and autonomic fear responses compared to controls at the stage of fear acquisition. During the stage of fear consolidation, the SD group displayed decreased ventromedial prefrontal cortex (vmPFC) activity and concomitantly increased amygdala activity. Moreover, in the SD group fear acquisition-induced brain activity changes in amygdala were positively correlated with both, subjective and autonomic fear indices during acquisition, whereas in controls changes vmPFC activity were positively correlated with fear indices during acquisition. Together, the present findings suggested that SD may weaken the top-down ability of the vmPFC to regulate amygdala activity during fear memory consolidation. Moreover, subjective and objective fear at fear acquisition stage can predict the change of brain activity in amygdala in fear memory consolidation following SD. Copyright © 2018 Elsevier Inc. All rights reserved.

On spacecraft maneuvers control subject to propellant engine modes.

PubMed

Mazinan, A H

2015-09-01

The paper attempts to address a new control approach to spacecraft maneuvers based upon the modes of propellant engine. A realization of control strategy is now presented in engine on mode (high thrusts as well as further low thrusts), which is related to small angle maneuvers and engine off mode (specified low thrusts), which is also related to large angle maneuvers. There is currently a coarse-fine tuning in engine on mode. It is shown that the process of handling the angular velocities are finalized via rate feedback system in engine modes, where the angular rotations are controlled through quaternion based control (QBCL)strategy in engine off mode and these ones are also controlled through an optimum PID (OPIDH) strategy in engine on mode. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Using Mean Orbit Period in Mars Reconnaissance Orbiter Maneuver Design

NASA Technical Reports Server (NTRS)

Chung, Min-Kun J.; Menon, Premkumar R.; Wagner, Sean V.; Williams, Jessica L.

2014-01-01

Mars Reconnaissance Orbiter (MRO) has provided communication relays for a number of Mars spacecraft. In 2016 MRO is expected to support a relay for NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft. In addition, support may be needed by another mission, ESA's ExoMars EDL Demonstrator Module's (EDM), only 21 days after the InSight coverage. The close proximity of these two events presents a unique challenge to a conventional orbit synchronization maneuver where one deterministic maneuver is executed prior to each relay. Since the two events are close together and the difference in required phasing between InSight and EDM may be up to half an orbit (yielding a large execution error), the downtrack timing error can increase rapidly at the EDM encounter. Thus, a new maneuver strategy that does not require a deterministic maneuver in-between the two events (with only a small statistical cleanup) is proposed in the paper. This proposed strategy rests heavily on the stability of the mean orbital period. The ability to search and set the specified mean period is fundamental in the proposed maneuver design as well as in understanding the scope of the problem. The proposed strategy is explained and its result is used to understand and solve the problem in the flight operations environment.

Optimal attitude maneuver execution for the Advanced Composition Explorer (ACE) mission

NASA Technical Reports Server (NTRS)

Woodard, Mark A.; Baker, David

1995-01-01

The Advanced Composition Explorer (ACE) spacecraft will require frequent attitude reorientations in order to maintain the spacecraft high gain antenna (HGA) within 3 deg of earth-pointing. These attitude maneuvers will be accomplished by employing a series of ground-commanded thruster pulses, computed by ground operations personnel, to achieve the desired change in the spacecraft angular momentum vector. With each maneuver, attitude nutation will be excited. Large nutation angles are undesirable from a science standpoint. It is important that the thruster firings be phased properly in order to minimize the nutation angle at the end of the maneuver so that science collection time is maximized. The analysis presented derives a simple approximation for the nutation contribution resulting from a series of short thruster burns. Analytic equations are derived which give the induced nutation angle as a function of the number of small thruster burns used to execute the attitude maneuver and the phasing of the burns. The results show that by properly subdividing the attitude burns, the induced nutation can be kept low. The analytic equations are also verified through attitude dynamics simulation and simulation results are presented. Finally, techniques for quantifying the post-maneuver nutation are discussed.

Determination of the optimal conditions for inclination maneuvers using a Swing-by

NASA Astrophysics Data System (ADS)

Moura, O.; Celestino, C. C.; Prado, A. F. B. A.

2018-05-01

The search for methods to reduce the fuel consumption in orbital transfers is something relevant and always current in astrodynamics. Therefore, the maneuvers assisted by the gravity, also called Swing-by maneuvers, can be an advantageous option to save fuel. The proposal of the present research is to explore the influence of some parameters in a Swing-by of an artificial satellite orbiting a planet with one of the moons of this mother planet, with the goal of changing the inclination of the artificial satellite around the main body of the system. The fuel consumption of this maneuver is compared with the required consumption to perform the same change of inclination using the classical approach of impulsive maneuvers.

Using the Two-Burn Escape Maneuver for Fast Transfers in the Solar System and Beyond

NASA Technical Reports Server (NTRS)

Adams, Robert B.; Richardson, Georgia A.

2010-01-01

The two-burn maneuver to escape the gravitational pull of a central body is described. The maneuver, originally suggested by Hermann Oberth, improves efficiency considerably for a wide range of missions of interest in space exploration and scientific investigation. A clear delineation of when the maneuver is more effective is given, as are methods to extract the most advantage when using the maneuver. Some examples are given of how this maneuver can enable exploration of the outer solar system, near interstellar space, and crewed missions to Mars and beyond. The maneuver has the potential to halve the required infrastructure associated with a crewed mission to Mars and achieve increased solar escape velocities with existing spacecraft technologies.

Algorithms for Maneuvering Spacecraft Around Small Bodies

NASA Technical Reports Server (NTRS)

Acikmese, A. Bechet; Bayard, David

2006-01-01

A document describes mathematical derivations and applications of autonomous guidance algorithms for maneuvering spacecraft in the vicinities of small astronomical bodies like comets or asteroids. These algorithms compute fuel- or energy-optimal trajectories for typical maneuvers by solving the associated optimal-control problems with relevant control and state constraints. In the derivations, these problems are converted from their original continuous (infinite-dimensional) forms to finite-dimensional forms through (1) discretization of the time axis and (2) spectral discretization of control inputs via a finite number of Chebyshev basis functions. In these doubly discretized problems, the Chebyshev coefficients are the variables. These problems are, variously, either convex programming problems or programming problems that can be convexified. The resulting discrete problems are convex parameter-optimization problems; this is desirable because one can take advantage of very efficient and robust algorithms that have been developed previously and are well established for solving such problems. These algorithms are fast, do not require initial guesses, and always converge to global optima. Following the derivations, the algorithms are demonstrated by applying them to numerical examples of flyby, descent-to-hover, and ascent-from-hover maneuvers.

An assessment of the ICE6G_C(VM5a) glacial isostatic adjustment model

NASA Astrophysics Data System (ADS)

Purcell, A.; Tregoning, P.; Dehecq, A.

2016-05-01

The recent release of the next-generation global ice history model, ICE6G_C(VM5a), is likely to be of interest to a wide range of disciplines including oceanography (sea level studies), space gravity (mass balance studies), glaciology, and, of course, geodynamics (Earth rheology studies). In this paper we make an assessment of some aspects of the ICE6G_C(VM5a) model and show that the published present-day radial uplift rates are too high along the eastern side of the Antarctic Peninsula (by ˜8.6 mm/yr) and beneath the Ross Ice Shelf (by ˜5 mm/yr). Furthermore, the published spherical harmonic coefficients—which are meant to represent the dimensionless present-day changes due to glacial isostatic adjustment (GIA)—contain excessive power for degree ≥90, do not agree with physical expectations and do not represent accurately the ICE6G_C(VM5a) model. We show that the excessive power in the high-degree terms produces erroneous uplift rates when the empirical relationship of Purcell et al. (2011) is applied, but when correct Stokes coefficients are used, the empirical relationship produces excellent agreement with the fully rigorous computation of the radial velocity field, subject to the caveats first noted by Purcell et al. (2011). Using the Australian National University (ANU) groups CALSEA software package, we recompute the present-day GIA signal for the ice thickness history and Earth rheology used by Peltier et al. (2015) and provide dimensionless Stokes coefficients that can be used to correct satellite altimetry observations for GIA over oceans and by the space gravity community to separate GIA and present-day mass balance change signals. We denote the new data sets as ICE6G_ANU.

Optimal Electrodynamic Tether Phasing Maneuvers

NASA Technical Reports Server (NTRS)

Bitzer, Matthew S.; Hall, Christopher D.

2007-01-01

We study the minimum-time orbit phasing maneuver problem for a constant-current electrodynamic tether (EDT). The EDT is assumed to be a point mass and the electromagnetic forces acting on the tether are always perpendicular to the local magnetic field. After deriving and non-dimensionalizing the equations of motion, the only input parameters become current and the phase angle. Solution examples, including initial Lagrange costates, time of flight, thrust plots, and thrust angle profiles, are given for a wide range of current magnitudes and phase angles. The two-dimensional cases presented use a non-tilted magnetic dipole model, and the solutions are compared to existing literature. We are able to compare similar trajectories for a constant thrust phasing maneuver and we find that the time of flight is longer for the constant thrust case with similar initial thrust values and phase angles. Full three-dimensional solutions, which use a titled magnetic dipole model, are also analyzed for orbits with small inclinations.

Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

NASA Image and Video Library

1973-08-27

SL3-107-1215 (27 Aug. 1973) --- Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the forward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. One of his fellow crewmen took this photograph with a 35mm Nikon camera. Bean is strapped into the back mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). The dome area is about 22 feet in diameter and 19 feet from top to bottom. Photo credit: NASA

Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

NASA Image and Video Library

1973-08-18

SL3-108-1304 (July-September 1973) --- Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the forward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). This ASMU experiment is being done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom. Photo credit: NASA

C3 in Maneuver Warfare: The Expanding Role of the Communications Officer

DTIC Science & Technology

1991-04-01

command, control, and communications (C3 ) process employed within the Marine Air Ground Task Force (MAGTF). Over the past two decades, the rapid...information to the right people at the right time. This paper presents a philosophical understanding of maneuver C3 and the communication officer’s...necessary to support maneuver warfare. Figure 1 depicts; thi:; dual role of C3 and serves as an outline for our paper . Maneuver C3 Architecture

A Comparison of Obstetric Maneuvers for the Acute Management of Shoulder Dystocia

PubMed Central

Hoffman, Matthew K; Bailit, Jennifer L; Branch, D. Ware; Burkman, Ronald T; Van Veldhusien, Paul; Lu, Li; Kominiarek, Michelle A.; Hibbard, Judith U; Landy, Helain J; Haberman, Shoshana; Wilkins, Isabelle; Gonzalez Quintero, Victor H; Gregory, Kimberly D; Hatjis, Christos G; Ramirez, Mildred M; Reddy, Uma M.; Troendle, James; Zhang, Jun

2011-01-01

Objective To assess the efficacy of obstetric maneuvers for resolving shoulder dystocia, and the effect that these maneuvers have on neonatal injury when shoulder dystocia occurs. Methods Using an electronic database encompassing 206,969 deliveries, we identified all women with a vertex fetus beyond 34 0/7 weeks of gestation who incurred a shoulder dystocia during the process of delivery. Women whose fetuses had a congenital anomaly and women with an antepartum stillbirth were excluded. Medical records of all cases were reviewed by trained abstractors. Cases involving neonatal injury (defined as brachial plexus injury, clavicular or humerus fracture, or hypoxic ischemic encephalopathy or intrapartum neonatal death attributed to the shoulder dystocia) were compared to those without injury. RESULTS Among 132,098 women who delivered a term cephalic liveborn fetus vaginally, 2,018 incurred a shoulder dystocia (1.5%), and 101 (5.2%) of these incurred a neonatal injury. Delivery of the posterior shoulder was associated with the highest rate of delivery when compared to other maneuvers (84.4% compared with 24.3% to 72.0% for other maneuvers; P<.005 to P<.001) and similar rates of neonatal injury (8.4% compared with 6.1% to 14.0%; P=.23 to P=.7). The total number of maneuvers performed significantly correlated with the rate of neonatal injury (P<.001). CONCLUSIONS Delivery of the posterior shoulder should be considered following McRoberts maneuver and suprapubic pressure in the management of shoulder dystocia. The need for additional maneuvers was associated with higher rates of neonatal injury. PMID:21555962

Thermally-Constrained Fuel-Optimal ISS Maneuvers

NASA Technical Reports Server (NTRS)

Bhatt, Sagar; Svecz, Andrew; Alaniz, Abran; Jang, Jiann-Woei; Nguyen, Louis; Spanos, Pol

2015-01-01

Optimal Propellant Maneuvers (OPMs) are now being used to rotate the International Space Station (ISS) and have saved hundreds of kilograms of propellant over the last two years. The savings are achieved by commanding the ISS to follow a pre-planned attitude trajectory optimized to take advantage of environmental torques. The trajectory is obtained by solving an optimal control problem. Prior to use on orbit, OPM trajectories are screened to ensure a static sun vector (SSV) does not occur during the maneuver. The SSV is an indicator that the ISS hardware temperatures may exceed thermal limits, causing damage to the components. In this paper, thermally-constrained fuel-optimal trajectories are presented that avoid an SSV and can be used throughout the year while still reducing propellant consumption significantly.

An object correlation and maneuver detection approach for space surveillance

NASA Astrophysics Data System (ADS)

Huang, Jian; Hu, Wei-Dong; Xin, Qin; Du, Xiao-Yong

2012-10-01

Object correlation and maneuver detection are persistent problems in space surveillance and maintenance of a space object catalog. We integrate these two problems into one interrelated problem, and consider them simultaneously under a scenario where space objects only perform a single in-track orbital maneuver during the time intervals between observations. We mathematically formulate this integrated scenario as a maximum a posteriori (MAP) estimation. In this work, we propose a novel approach to solve the MAP estimation. More precisely, the corresponding posterior probability of an orbital maneuver and a joint association event can be approximated by the Joint Probabilistic Data Association (JPDA) algorithm. Subsequently, the maneuvering parameters are estimated by optimally solving the constrained non-linear least squares iterative process based on the second-order cone programming (SOCP) algorithm. The desired solution is derived according to the MAP criterions. The performance and advantages of the proposed approach have been shown by both theoretical analysis and simulation results. We hope that our work will stimulate future work on space surveillance and maintenance of a space object catalog.

Inlet Flow Characteristics During Rapid Maneuvers for an F/A-18A Airplane

NASA Technical Reports Server (NTRS)

Steenken, William G.; Williams, John G.; Walsh, Kevin R.

1999-01-01

The F404-GE-400 engine powered F/A-18A High Alpha Research Vehicle (HARV) was used to examine the characteristics of inlet airflow during rapid aircraft maneuvers. A study of the degree of similarity between inlet data obtained during rapid aircraft maneuvers and inlet data obtained at steady aerodynamic attitudes was conducted at the maximum engine airflow of approximately 145 Ibm/sec using a computer model that was generated from inlet data obtained during steady aerodynamic maneuvers. Results show that rapid-maneuver inlet recoveries agreed very well with the recoveries obtained at equivalent stabilized angle-of-attack conditions. The peak dynamic circumferential distortion values obtained during rapid maneuvers agreed within 0.01 units of distortion over the 10 - 38 degree angle of attack range with the values obtained during steady aerodynamic maneuvers while similar agreement was found for the peak dynamic radial distortion values up to 29 degrees angle-of-attack. Exceedences of the rapid-maneuver peak dynamic circumferential distortion values relative to the peak distortion model values at steady attitudes occurred only at low or negative angles of attack and were inconsequential from an engine-stability assessment point of view. The results of this study validate the current industry practice of testing at steady aerodynamic conditions to characterize inlet recovery and peak dynamic distortion levels.

VMCast: A VM-Assisted Stability Enhancing Solution for Tree-Based Overlay Multicast

PubMed Central

Gu, Weidong; Zhang, Xinchang; Gong, Bin; Zhang, Wei; Wang, Lu

2015-01-01

Tree-based overlay multicast is an effective group communication method for media streaming applications. However, a group member’s departure causes all of its descendants to be disconnected from the multicast tree for some time, which results in poor performance. The above problem is difficult to be addressed because overlay multicast tree is intrinsically instable. In this paper, we proposed a novel stability enhancing solution, VMCast, for tree-based overlay multicast. This solution uses two types of on-demand cloud virtual machines (VMs), i.e., multicast VMs (MVMs) and compensation VMs (CVMs). MVMs are used to disseminate the multicast data, whereas CVMs are used to offer streaming compensation. The used VMs in the same cloud datacenter constitute a VM cluster. Each VM cluster is responsible for a service domain (VMSD), and each group member belongs to a specific VMSD. The data source delivers the multicast data to MVMs through a reliable path, and MVMs further disseminate the data to group members along domain overlay multicast trees. The above approach structurally improves the stability of the overlay multicast tree. We further utilized CVM-based streaming compensation to enhance the stability of the data distribution in the VMSDs. VMCast can be used as an extension to existing tree-based overlay multicast solutions, to provide better services for media streaming applications. We applied VMCast to two application instances (i.e., HMTP and HCcast). The results show that it can obviously enhance the stability of the data distribution. PMID:26562152

VMCast: A VM-Assisted Stability Enhancing Solution for Tree-Based Overlay Multicast.

PubMed

Gu, Weidong; Zhang, Xinchang; Gong, Bin; Zhang, Wei; Wang, Lu

2015-01-01

Tree-based overlay multicast is an effective group communication method for media streaming applications. However, a group member's departure causes all of its descendants to be disconnected from the multicast tree for some time, which results in poor performance. The above problem is difficult to be addressed because overlay multicast tree is intrinsically instable. In this paper, we proposed a novel stability enhancing solution, VMCast, for tree-based overlay multicast. This solution uses two types of on-demand cloud virtual machines (VMs), i.e., multicast VMs (MVMs) and compensation VMs (CVMs). MVMs are used to disseminate the multicast data, whereas CVMs are used to offer streaming compensation. The used VMs in the same cloud datacenter constitute a VM cluster. Each VM cluster is responsible for a service domain (VMSD), and each group member belongs to a specific VMSD. The data source delivers the multicast data to MVMs through a reliable path, and MVMs further disseminate the data to group members along domain overlay multicast trees. The above approach structurally improves the stability of the overlay multicast tree. We further utilized CVM-based streaming compensation to enhance the stability of the data distribution in the VMSDs. VMCast can be used as an extension to existing tree-based overlay multicast solutions, to provide better services for media streaming applications. We applied VMCast to two application instances (i.e., HMTP and HCcast). The results show that it can obviously enhance the stability of the data distribution.

Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

NASA Technical Reports Server (NTRS)

1973-01-01

Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the foreward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). He is wearing a pressure suit for this run of the M509 experiment, but other ASMU tests are done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

Adapting Covariance Propagation to Account for the Presence of Modeled and Unmodeled Maneuvers

NASA Technical Reports Server (NTRS)

Schiff, Conrad

2006-01-01

This paper explores techniques that can be used to adapt the standard linearized propagation of an orbital covariance matrix to the case where there is a maneuver and an associated execution uncertainty. A Monte Carlo technique is used to construct a final orbital covariance matrix for a 'prop-burn-prop' process that takes into account initial state uncertainty and execution uncertainties in the maneuver magnitude. This final orbital covariance matrix is regarded as 'truth' and comparisons are made with three methods using modified linearized covariance propagation. The first method accounts for the maneuver by modeling its nominal effect within the state transition matrix but excludes the execution uncertainty by omitting a process noise matrix from the computation. The second method does not model the maneuver but includes a process noise matrix to account for the uncertainty in its magnitude. The third method, which is essentially a hybrid of the first two, includes the nominal portion of the maneuver via the state transition matrix and uses a process noise matrix to account for the magnitude uncertainty. The first method is unable to produce the final orbit covariance except in the case of zero maneuver uncertainty. The second method yields good accuracy for the final covariance matrix but fails to model the final orbital state accurately. Agreement between the simulated covariance data produced by this method and the Monte Carlo truth data fell within 0.5-2.5 percent over a range of maneuver sizes that span two orders of magnitude (0.1-20 m/s). The third method, which yields a combination of good accuracy in the computation of the final covariance matrix and correct accounting for the presence of the maneuver in the nominal orbit, is the best method for applications involving the computation of times of closest approach and the corresponding probability of collision, PC. However, applications for the two other methods exist and are briefly discussed. Although

A Maneuvering Flight Noise Model for Helicopter Mission Planning

NASA Technical Reports Server (NTRS)

Greenwood, Eric; Rau, Robert; May, Benjamin; Hobbs, Christopher

2015-01-01

A new model for estimating the noise radiation during maneuvering flight is developed in this paper. The model applies the Quasi-Static Acoustic Mapping (Q-SAM) method to a database of acoustic spheres generated using the Fundamental Rotorcraft Acoustics Modeling from Experiments (FRAME) technique. A method is developed to generate a realistic flight trajectory from a limited set of waypoints and is used to calculate the quasi-static operating condition and corresponding acoustic sphere for the vehicle throughout the maneuver. By using a previously computed database of acoustic spheres, the acoustic impact of proposed helicopter operations can be rapidly predicted for use in mission-planning. The resulting FRAME-QS model is applied to near-horizon noise measurements collected for the Bell 430 helicopter undergoing transient pitch up and roll maneuvers, with good agreement between the measured data and the FRAME-QS model.

Multislice CT imaging of ruptured left sinus of Valsalva aneurysm with fistulous track between left sinus and right atrium.

PubMed

Pampapati, Praveenkumar; Rao, Hejmadi Tati Gururaj; Radhesh, Srinivasan; Anand, Hejjaji Krishnamurthy; Praveen, Lokkur Srinivasamurthy

2011-01-01

Sinus of valsalva aneurysm is a rare condition arising from any of the three aortic sinuses. Among them, an aneurysm arising from the left coronary sinus is the rarest. Most of these cases were earlier diagnosed using echocardiography and conventional angiography. But with the availability of advanced imaging modalities like 64 slice cardiac CT and MR modalities, this condition can be accurately assessed noninvasively. We report a case of ruptured aneurysm originating from the left coronary sinus with a long windsock type of fistulous track between the aneurysm and right atrium evaluated by 64 slice cardiac CT imaging. This was later confirmed perioperatively.

Spacecraft Guidance Strategies for Proximity Maneuvering and Close Approach with a Tumbling Object

DTIC Science & Technology

2010-03-01

R., and Junkins, J. L. (1984), ‘Optimal Open-Loop and Stable Feedback Control of Rigid Spacecraft Attitude Maneuvers ,’ The Journal of the... SPACECRAFT GUIDANCE STRATEGIES FOR PROXIMITY MANEUVERING AND CLOSE APPROACH WITH A TUMBLING OBJECT by George A. Boyarko March 2010...Dissertation 4. TITLE AND SUBTITLE: Spacecraft Guidance Strategies for Proximity Maneuvering and Close Approach with a Tumbling Object 6. AUTHOR

Investigation of piloting aids for manual control of hypersonic maneuvers

NASA Technical Reports Server (NTRS)

Raney, David L.; Phillips, Michael R.; Person, Lee H., Jr.

1995-01-01

An investigation of piloting aids designed to provide precise maneuver control for an air-breathing hypersonic vehicle is described. Stringent constraints and nonintuitive high-speed flight effects associated with maneuvering in the hypersonic regime raise the question of whether manual control of such a vehicle should even be considered. The objectives of this research were to determine the extent of manual control that is desirable for a vehicle maneuvering in this regime and to identify the form of aids that must be supplied to the pilot to make such control feasible. A piloted real-time motion-based simulation of a hypersonic vehicle concept was used for this study, and the investigation focused on a single representative cruise turn maneuver. Piloting aids, which consisted of an auto throttle, throttle director, autopilot, flight director, and two head-up display configurations, were developed and evaluated. Two longitudinal control response types consisting of a rate-command/attitude-hold system and a load factor-rate/load-factor-hold system were also compared. The complete set of piloting aids, which consisted of the autothrottle, throttle director, and flight director, improved the average Cooper-Harper flying qualities ratings from 8 to 2.6, even though identical inner-loop stability and control augmentation was provided in all cases. The flight director was determined to be the most critical of these aids, and the cruise turn maneuver was unachievable to adequate performance specifications in the absence of this flight director.

Tether cutting maneuver in swing-by trajectory

NASA Astrophysics Data System (ADS)

Yamasaki, Tsubasa; Bando, Mai; Hokamoto, Shinji

2018-01-01

The swing-by maneuver is known as a method to change the velocity of a spacecraft by using the gravity force of the celestial body. The powered swing-by has been studied to enhance the velocity change during the swing-by maneuver. This paper studies another way of the powered swing-by using tether cutting, which does not require additional propellant consumption, and shows that the proposed powered swing-by can increase the effect of the swing-by as same as using impulsive thrust. Moreover, it is discussed whether the system has possibility to realize both the powered swing-by of a mother satellite and the planetary capture of a subsatellite simultaneously.

Dynamics and control of flexible spacecraft during and after slewing maneuvers

NASA Technical Reports Server (NTRS)

Kakad, Yogendra P.

1989-01-01

The dynamics and control of slewing maneuvers of NASA Spacecraft COntrol Laboratory Experiment (SCOLE) are analyzed. The control problem of slewing maneuvers of SCOLE is formulated in terms of an arbitrary maneuver about any given axis. The control system is developed for the combined problem of rigid-body slew maneuver and vibration suppression of the flexible appendage. The control problem formulation incorporates the nonlinear dynamical equations derived previously, and is expressed in terms of a two-point boundary value problem utilizing a quadratic type of performance index. The two-point boundary value problem is solved as a hierarchical control problem with the overall system being split in terms of two subsystems, namely the slewing of the entire assembly and the vibration suppression of the flexible antenna. The coupling variables between the two dynamical subsystems are identified and these two subsystems for control purposes are treated independently in parallel at the first level. Then the state-space trajectory of the combined problem is optimized at the second level.

Huang's three-step maneuver shortens the learning curve of laparoscopic spleen-preserving splenic hilar lymphadenectomy.

PubMed

Huang, Chang-Ming; Huang, Ze-Ning; Zheng, Chao-Hui; Li, Ping; Xie, Jian-Wei; Wang, Jia-Bin; Lin, Jian-Xian; Jun, Lu; Chen, Qi-Yue; Cao, Long-Long; Lin, Mi; Tu, Ru-Hong

2017-12-01

The goal of this study was to investigate the difference between the learning curves of different maneuvers in laparoscopic spleen-preserving splenic hilar lymphadenectomy for advanced upper gastric cancer. From January 2010 to April 2014, 53 consecutive patients who underwent laparoscopic spleen-preserving splenic hilar lymphadenectomy via the traditional-step maneuver (group A) and 53 consecutive patients via Huang's three-step maneuver (group B) were retrospectively analyzed. No significant difference in patient characteristics were found between the two groups. The learning curves of groups A and B were divided into phase 1 (1-43 cases and 1-30 cases, respectively) and phase 2 (44-53 cases and 31-53 cases, respectively). Compared with group A, the dissection time, bleeding loss and vascular injury were significantly decreased in group B. No significant differences in short-term outcomes were found between the two maneuvers. The multivariate analysis indicated that the body mass index, short gastric vessels, splenic artery type and maneuver were significantly associated with the dissection time in group B. No significant difference in the survival curve was found between the maneuvers. The learning curve of Huang's three-step maneuver was shorter than that of the traditional-step maneuver, and the former represents an ideal maneuver for laparoscopic spleen-preserving splenic hilar lymphadenectomy.To shorten the learning curve at the beginning of laparoscopic spleen-preserving splenic hilar lymphadenectomy, beginners should beneficially use Huang's three-step maneuver and select patients with advanced upper gastric cancer with a body mass index of less than 25 kg/m 2 and the concentrated type of splenic artery. Copyright © 2017. Published by Elsevier Ltd.

Identification of aerodynamic models for maneuvering aircraft

NASA Technical Reports Server (NTRS)

Chin, Suei; Lan, C. Edward

1990-01-01

Due to the requirement of increased performance and maneuverability, the flight envelope of a modern fighter is frequently extended to the high angle-of-attack regime. Vehicles maneuvering in this regime are subjected to nonlinear aerodynamic loads. The nonlinearities are due mainly to three-dimensional separated flow and concentrated vortex flow that occur at large angles of attack. Accurate prediction of these nonlinear airloads is of great importance in the analysis of a vehicle's flight motion and in the design of its flight control system. A satisfactory evaluation of the performance envelope of the aircraft may require a large number of coupled computations, one for each change in initial conditions. To avoid the disadvantage of solving the coupled flow-field equations and aircraft's motion equations, an alternate approach is to use a mathematical modeling to describe the steady and unsteady aerodynamics for the aircraft equations of motion. Aerodynamic forces and moments acting on a rapidly maneuvering aircraft are, in general, nonlinear functions of motion variables, their time rate of change, and the history of maneuvering. A numerical method was developed to analyze the nonlinear and time-dependent aerodynamic response to establish the generalized indicial function in terms of motion variables and their time rates of change.

Development of a cooperative operational rendezvous plan for Eureca and other maneuvering Shuttle payloads

NASA Technical Reports Server (NTRS)

Gavin, R. T.

1987-01-01

This paper discusses the development of a new class of US Space Shuttle rendezvous missions which involve a maneuvering target vehicle. The objective of the analysis was to develop an operational plan to take advantage of the target spacecraft's maneuvering ability by making it responsible for a portion of the maneuvers necessary to achieve rendezvous. This work resulted in the development of a region in space relative to the Shuttle, called the control box, into which the target vehicle maneuvers. Furthermore, a mission operations plan was developed to implement the control box technique.

Precision Closed-Loop Orbital Maneuvering System Design and Performance for the Magnetospheric Multiscale Formation

NASA Technical Reports Server (NTRS)

Chai, Dean J.; Queen, Steven Z.; Placanica, Samuel J.

2015-01-01

NASAs Magnetospheric Multiscale (MMS) mission successfully launched on March 13,2015 (UTC) consists of four identically instrumented spin-stabilized observatories that function as a constellation to study magnetic reconnection in space. The need to maintain sufficiently accurate spatial and temporal formation resolution of the observatories must be balanced against the logistical constraints of executing overly-frequent maneuvers on a small fleet of spacecraft. These two considerations make for an extremely challenging maneuver design problem. This paper focuses on the design elements of a 6-DOF spacecraft attitude control and maneuvering system capable of delivering the high-precision adjustments required by the constellation designers specifically, the design, implementation, and on-orbit performance of the closed-loop formation-class maneuvers that include initialization, maintenance, and re-sizing. The maneuvering control system flown on MMS utilizes a micro-gravity resolution accelerometer sampled at a high rate in order to achieve closed-loop velocity tracking of an inertial target with arc-minute directional and millimeter-per second magnitude accuracy. This paper summarizes the techniques used for correcting bias drift, sensor-head offsets, and centripetal aliasing in the acceleration measurements. It also discusses the on-board pre-maneuver calibration and compensation algorithms as well as the implementation of the post-maneuver attitude adjustments.

Constraining models of postglacial rebound using space geodesy: a detailed assessment of model ICE-5G (VM2) and its relatives

NASA Astrophysics Data System (ADS)

Argus, Donald F.; Peltier, W. Richard

2010-05-01

Using global positioning system, very long baseline interferometry, satellite laser ranging and Doppler Orbitography and Radiopositioning Integrated by Satellite observations, including the Canadian Base Network and Fennoscandian BIFROST array, we constrain, in models of postglacial rebound, the thickness of the ice sheets as a function of position and time and the viscosity of the mantle as a function of depth. We test model ICE-5G VM2 T90 Rot, which well fits many hundred Holocene relative sea level histories in North America, Europe and worldwide. ICE-5G is the deglaciation history having more ice in western Canada than ICE-4G; VM2 is the mantle viscosity profile having a mean upper mantle viscosity of 0.5 × 1021Pas and a mean uppermost-lower mantle viscosity of 1.6 × 1021Pas T90 is an elastic lithosphere thickness of 90 km; and Rot designates that the model includes (rotational feedback) Earth's response to the wander of the North Pole of Earth's spin axis towards Canada at a speed of ~1° Myr-1. The vertical observations in North America show that, relative to ICE-5G, the Laurentide ice sheet at last glacial maximum (LGM) at ~26 ka was (1) much thinner in southern Manitoba, (2) thinner near Yellowknife (Northwest Territories), (3) thicker in eastern and southern Quebec and (4) thicker along the northern British Columbia-Alberta border, or that ice was unloaded from these areas later (thicker) or earlier (thinner) than in ICE-5G. The data indicate that the western Laurentide ice sheet was intermediate in mass between ICE-5G and ICE-4G. The vertical observations and GRACE gravity data together suggest that the western Laurentide ice sheet was nearly as massive as that in ICE-5G but distributed more broadly across northwestern Canada. VM2 poorly fits the horizontal observations in North America, predicting places along the margins of the Laurentide ice sheet to be moving laterally away from the ice centre at 2 mm yr-1 in ICE-4G and 3 mm yr-1 in ICE-5G, in

UAS Well Clear Recovery Against Non-Cooperative Intruders Using Vertical Maneuvers

NASA Technical Reports Server (NTRS)

Cone, Andrew C.; Thipphavong, David; Lee, Seung Man; Santiago, Confesor

2017-01-01

This paper documents a study that drove the development of a mathematical expression in the detect-and-avoid (DAA) minimum operational performance standards (MOPS) for unmanned aircraft systems (UAS). This equation describes the conditions under which vertical maneuver guidance should be provided during recovery of DAA well clear separation with a non-cooperative VFR aircraft. Although the original hypothesis was that vertical maneuvers for DAA well clear recovery should only be offered when sensor vertical rate errors are small, this paper suggests that UAS climb and descent performance should be considered-in addition to sensor errors for vertical position and vertical rate-when determining whether to offer vertical guidance. A fast-time simulation study involving 108,000 encounters between a UAS and a non-cooperative visual-flight-rules aircraft was conducted. Results are presented showing that, when vertical maneuver guidance for DAA well clear recovery was suppressed, the minimum vertical separation increased by roughly 50 feet (or horizontal separation by 500 to 800 feet). However, the percentage of encounters that had a risk of collision when performing vertical well clear recovery maneuvers was reduced as UAS vertical rate performance increased and sensor vertical rate errors decreased. A class of encounter is identified for which vertical-rate error had a large effect on the efficacy of horizontal maneuvers due to the difficulty of making the correct left/right turn decision: crossing conflict with intruder changing altitude. Overall, these results support logic that would allow vertical maneuvers when UAS vertical performance is sufficient to avoid the intruder, based on the intruder's estimated vertical position and vertical rate, as well as the vertical rate error of the UAS' sensor.

Optimizing interplanetary trajectories with deep space maneuvers. M.S. Thesis

NASA Technical Reports Server (NTRS)

Navagh, John

1993-01-01

Analysis of interplanetary trajectories is a crucial area for both manned and unmanned missions of the Space Exploration Initiative. A deep space maneuver (DSM) can improve a trajectory in much the same way as a planetary swingby. However, instead of using a gravitational field to alter the trajectory, the on-board propulsion system of the spacecraft is used when the vehicle is not near a planet. The purpose is to develop an algorithm to determine where and when to use deep space maneuvers to reduce the cost of a trajectory. The approach taken to solve this problem uses primer vector theory in combination with a non-linear optimizing program to minimize Delta(V). A set of necessary conditions on the primer vector is shown to indicate whether a deep space maneuver will be beneficial. Deep space maneuvers are applied to a round trip mission to Mars to determine their effect on the launch opportunities. Other studies which were performed include cycler trajectories and Mars mission abort scenarios. It was found that the software developed was able to locate quickly DSM's which lower the total Delta(V) on these trajectories.

Modeling of ground based laser propagation to low Earth orbit object for maneuver

NASA Astrophysics Data System (ADS)

Smith, Liam C.; Allen, Jeffrey H.; Bold, Matthew M.

2017-08-01

The Space Environment Research Centre (SERC) endeavors to demonstrate the ability to maneuver high area to mass ratio objects using ground based lasers. Lockheed Martin has been leading system performance modeling for this project that includes high power laser propagation through the atmosphere, target interactions and subsequent orbital maneuver of the object. This paper will describe the models used, model assumptions and performance estimates for laser maneuver demonstration.

Mapping sequence performed during the STS-115 R-Bar Pitch Maneuver

NASA Image and Video Library

2006-09-11

ISS013-E-79880 (11 Sept. 2006) --- This view of part of the starboard wing and one of the Orbital Maneuvering System (OMS) pods of the Space Shuttle Atlantis was provided by an Expedition 13 crew member during a backflip maneuver performed by the approaching visitors to the International Space Station.

Venous pump of the calf: a study of venous and muscular pressures.

PubMed

Alimi, Y S; Barthelemy, P; Juhan, C

1994-11-01

Little data are available concerning the relation between the muscular pumping mechanism and the variation of superficial and deep venous pressure during normal action of the calf pump; therefore we undertook this study to determine the pressure values in three compartments of the calf and in the deep and the superficial venous system and to establish correlation between muscular and venous pressure. Nine healthy young women with a mean age of 23 years (range 19 to 28 years) were examined. In the same calf, a muscular catheter was placed in the deep posterior compartment (DPC), in the superficial posterior compartment (SPC), and in the anterior tibial compartment (ATC), and a vascular catheter was placed in the popliteal vein and in the greater saphenous vein (GSV). The five lines of pressure were simultaneously recorded in the following situations: at rest, during Valsalva maneuver, foot flexion, and foot extension. The situation was studied with the patient in the following positions: decubitus, sitting, standing, and squatting. A final continuous recording was carried out after the patient had been walking for 5 minutes. Mean values with standard errors of muscular and venous pressure were established in each situation. At rest and during Valsalva maneuver, the muscular pressures did not vary, whereas venous pressures increased significantly when the patient was sitting and standing. On the other hand, squatting was associated with a rise in the muscular and vein pressures. Foot flexion entailed a significant increase in the ATC pressure and a rise in the GSV pressure, whereas foot extension caused the DPC pressure to rise without venous pressure modifications. Walking was associated with an alternating increase in the DPC, SPC, GSV and popliteal vein pressures when the foot was compressed to floor followed by a significant decrease when the foot pressure was released. The variations in the deep and superficial venous pressures when the patient is sitting and

Novel joint cupping clinical maneuver for ultrasonographic detection of knee joint effusions.

PubMed

Uryasev, Oleg; Joseph, Oliver C; McNamara, John P; Dallas, Apostolos P

2013-11-01

Knee effusions occur due to traumatic and atraumatic causes. Clinical diagnosis currently relies on several provocative techniques to demonstrate knee joint effusions. Portable bedside ultrasonography (US) is becoming an adjunct to diagnosis of effusions. We hypothesized that a US approach with a clinical joint cupping maneuver increases sensitivity in identifying effusions as compared to US alone. Using unembalmed cadaver knees, we injected fluid to create effusions up to 10 mL. Each effusion volume was measured in a lateral transverse location with respect to the patella. For each effusion we applied a joint cupping maneuver from an inferior approach, and re-measured the effusion. With increased volume of saline infusion, the mean depth of effusion on ultrasound imaging increased as well. Using a 2-mm cutoff, we visualized an effusion without the joint cupping maneuver at 2.5 mL and with the joint cupping technique at 1 mL. Mean effusion diameter increased on average 0.26 cm for the joint cupping maneuver as compared to without the maneuver. The effusion depth was statistically different at 2.5 and 7.5 mL (P < .05). Utilizing a joint cupping technique in combination with US is a valuable tool in assessing knee effusions, especially those of subclinical levels. Effusion measurements are complicated by uneven distribution of effusion fluid. A clinical joint cupping maneuver concentrates the fluid in one recess of the joint, increasing the likelihood of fluid detection using US. © 2013 Elsevier Inc. All rights reserved.

The Prospect of Responsive Spacecraft Using Aeroassisted, Trans-Atmospheric Maneuvers

DTIC Science & Technology

2014-06-19

skip entry aeroassisted maneuvers. By overflying a geographically diverse set of sample ground targets, comparative analysis indicates a significant... analysis . Depending on the chosen re- circularization altitude, the coupled optimal design can achieve an inclination change of 19.91 deg with 50-85...third phase also introduces the “Maneuver Performance Number” as a dimensionless means of comparative effectiveness analysis for both exo- and trans

Automatic evaluation of the Valsalva sinuses from cine-MRI

NASA Astrophysics Data System (ADS)

Blanchard, Cédric; Sliwa, Tadeusz; Lalande, Alain; Mohan, Pauliah; Bouchot, Olivier; Voisin, Yvon

2011-03-01

MRI appears to be particularly attractive for the study of the Sinuses of Valsalva (SV), however there is no global consensus on their suitable measurements. In this paper, we propose a new method, based on the mathematical morphology and combining a numerical geodesic reconstruction with an area estimation, to automatically evaluate the SV from a cine-MRI in a cross-sectional orientation. It consists in the extraction of the shape of the SV, the detection of relevant points (commissures, cusps and the centre of the SV), the measurement of relevant distances and in a classification of the valve as bicuspid or tricuspid by a metric evaluation of the SV. Our method was tested on 23 patient examinations and radii calculations were compared with a manual measurement. The classification of the valve as tricuspid or bicuspid was correct for all the cases. Moreover, there are an excellent correlation and an excellent concordance between manual and automatic measurements for images at diastolic phase (r= 0.97; y = x - 0.02; p=NS; mean of differences = -0.1 mm; standard deviation of differences = 2.3 mm) and at systolic phase (r= 0.96; y = 0.97 x + 0.80; p=NS ; mean of differences = -0.1 mm; standard deviation of differences = 2.4 mm). The cross-sectional orientation of the image acquisition plane conjugated with our automatic method provides a reliable morphometric evaluation of the SV, based on the automatic location of the centre of the SV, the commissure and the cusp positions. Measurements of distances between relevant points allow a precise evaluation of the SV.

An Independent and Coordinated Criterion for Kinematic Aircraft Maneuvers

NASA Technical Reports Server (NTRS)

Narkawicz, Anthony J.; Munoz, Cesar A.; Hagen, George

2014-01-01

This paper proposes a mathematical definition of an aircraft-separation criterion for kinematic-based horizontal maneuvers. It has been formally proved that kinematic maneu- vers that satisfy the new criterion are independent and coordinated for repulsiveness, i.e., the distance at closest point of approach increases whether one or both aircraft maneuver according to the criterion. The proposed criterion is currently used in NASA's Airborne Coordinated Resolution and Detection (ACCoRD) set of tools for the design and analysis of separation assurance systems.

Experimental progress of a 4K VM/PT hybrid cryocooler for pre-cooling 1K sorption cooler

NASA Astrophysics Data System (ADS)

Pan, Changzhao; Zhang, Tong; Wang, Jue; Chen, Liubiao; Guo, Jia; Zhou, Yuan; Wang, Junjie

2017-12-01

Sub-kelvin refrigerator has many applications in space detector and manned space station, such as for the transition-edge superconducting (TES) bolometers operated in the 50 mK range. In order to meet the requirement of space applications, the high efficient, vibration free and high stability refrigerator need to be designed. VM/PT hybrid cryocooler is a new type cryocooler capable of attaining temperature below 4K. As a low frequency Stirling type cryocooler, it has the advantages of high stability and high efficiency. Combined with the vibration free sorption cooler and ADR refrigerator, a novel sub-kelvin cooling chain can be designed for the TES bolometer. This paper presents the recent experimental progress of the 4K VM/PT hybrid cryocooler in our laboratory. By optimizing of regenerators, phase shifters and heat exchangers, a lowest temperature of 2.6K was attained. Based on this cryocooler, a preliminary sorption cooler could be designed.

Unique properties of the classical bovine spongiform encephalopathy strain and its emergence from H-type bovine spongiform encephalopathy substantiated by VM transmission studies.

PubMed

Bencsik, Anna; Leboidre, Mikael; Debeer, Sabine; Aufauvre, Claire; Baron, Thierry

2013-03-01

In addition to classical bovine spongiform encephalopathy (C-BSE), which is recognized as being at the origin of the human variant form of Creutzfeldt-Jakob disease, 2 rare phenotypes of BSE (H-type BSE [H-BSE] and L-type BSE [L-BSE]) were identified in 2004. H-type BSE and L-BSE are considered to be sporadic forms of prion disease in cattle because they differ from C-BSE with respect to incubation period, vacuolar pathology in the brain, and biochemical properties of the protease-resistant prion protein (PrP) in natural hosts and in some mouse models that have been tested. Recently, we showed that H-BSE transmitted to C57Bl/6 mice resulted in a dissociation of the phenotypic features, that is, some mice showed an H-BSE phenotype, whereas others had a C-BSE phenotype. Here, these 2 phenotypes were further studied in VM mice and compared with cattle C-BSE, H-BSE, and L-BSE. Serial passages from the C-BSE-like phenotype on VM mice retained similarities with C-BSE. Moreover, our results indicate that strains 301V and 301C derived from C-BSE transmitted to VM and C57Bl/6 mice, respectively, are fundamentally the same strain. These VM transmission studies confirm the unique properties of the C-BSE strain and support the emergence of a strain that resembles C-BSE from H-BSE.

Curiosity Sky Crane Maneuver, Artist Concept

NASA Image and Video Library

2011-10-03

This artist concept shows the sky crane maneuver during the descent of NASA Curiosity rover to the Martian surface. The sheer size of the rover over one ton, or 900 kilograms would preclude it from taking advantage of an airbag-assisted landing.

Demonstrative Maneuvers for Aircraft Agility Predictions

DTIC Science & Technology

2008-03-01

AIAA Paper 1996-3741. 19. Raymer , Daniel P. Aircraft Design: A Conceptual Approach. American Institute of Aeronautics and Astronautics, Inc., 3rd...Shaw, Robert L. Fighter Combat: Tactics and Maneuvering. Naval Institute Press, Annapolis, MD, 1985. 25. Smith, Steven W. The Scientist and

Effect of bird maneuver on frequency-domain helicopter EM response

USGS Publications Warehouse

Fitterman, D.V.; Yin, C.

2004-01-01

Bird maneuver, the rotation of the coil-carrying instrument pod used for frequency-domain helicopter electromagnetic surveys, changes the nominal geometric relationship between the bird-coil system and the ground. These changes affect electromagnetic coupling and can introduce errors in helicopter electromagnetic, (HEM) data. We analyze these effects for a layered half-space for three coil configurations: vertical coaxial, vertical coplanar, and horizontal coplanar. Maneuver effect is shown to have two components: one that is purely geometric and another that is inductive in nature. The geometric component is significantly larger. A correction procedure is developed using an iterative approach that uses standard HEM inversion routines. The maneuver effect correction reduces inversion misfit error and produces laterally smoother cross sections than obtained from uncorrected data. ?? 2004 Society of Exploration Geophysicists. All rights reserved.

[Study on anti +Gx respiratory maneuver and its training method].

PubMed

Xue, Yue-ying; You, Guang-xing; Wu, Bin; Liu, Xing-hua; Lu, Sheng-qiang; Xie, Bao-sheng

2002-12-01

Objective. To study the anti +Gx respiratory maneuver and its training method. Method. Seven young male subjects undertook the anti +Gx respiratory maneuver training. Their +Gx tolerances were examined on human centrifuge before and after training. The change of respiratory type, breath rate, electrocardiogram, heart rate, arterial oxygen saturation (SaO2), subjective symptom and vision were real-time monitored during the +Gx tolerance examination. Result. Compared with pre-training, the +Gx tolerance increased after training (P<0.05). Dyspnea and chest pain disappeared or obviously lightened and the magnitude of decrease of SaO2 decreased significantly (P<0.05). Conclusion. The above results suggested that the anti +Gx respiratory maneuver can effectively eliminate or alleviate dyspnea and chest pain induced by +Gx stress and increase human +Gx tolerance.

Prevention of shoulder dystocia: A randomized controlled trial to evaluate an obstetric maneuver.

PubMed

Poujade, Olivier; Azria, Elie; Ceccaldi, Pierre-François; Davitian, Carine; Khater, Carine; Chatel, Paul; Pernin, Emilie; Aflak, Nizar; Koskas, Martin; Bourgeois-Moine, Agnès; Hamou-Plotkine, Laurence; Valentin, Morgane; Renner, Jean-Paul; Roy, Carine; Estellat, Candice; Luton, Dominique

2018-08-01

Shoulder dystocia is a major obstetric emergency defined as a failure of delivery of the fetal shoulder(s). This study evaluated whether an obstetric maneuver, the push back maneuver performed gently on the fetal head during delivery, could reduce the risk of shoulder dystocia. We performed a multicenter, randomized, single-blind trial to compare the push back maneuver with usual care in parturient women at term. The primary outcome, shoulder dystocia, was considered to have occurred if, after delivery of the fetal head, any additional obstetric maneuver, beginning with the McRoberts maneuver, other than gentle downward traction and episiotomy was required. We randomly assigned 522 women to the push back maneuver group (group P) and 523 women to the standard vaginal delivery group (group S). Finally, 473 women assigned to group P and 472 women assigned to group S delivered vaginally. The rate of shoulder dystocia was significantly lower in group P (1·5%) than in group S (3·8%) (odds ratio [OR] 0·38 [0·16-0·92]; P = 0·03). After adjustment for predefined main risk factors, dystocia remained significantly lower in group P than in group S. There were no significant between-group differences in neonatal complications, including brachial plexus injury, clavicle fracture, hematoma and generalized asphyxia. In this trial in 945 women who delivered vaginally, the push back maneuver significantly decreased the risk of shoulder dystocia, as compared with standard vaginal delivery. Copyright © 2018 Elsevier B.V. All rights reserved.

A Fuel-Efficient Conflict Resolution Maneuver for Separation Assurance

NASA Technical Reports Server (NTRS)

Bowe, Aisha Ruth; Santiago, Confesor

2012-01-01

Automated separation assurance algorithms are envisioned to play an integral role in accommodating the forecasted increase in demand of the National Airspace System. Developing a robust, reliable, air traffic management system involves safely increasing efficiency and throughput while considering the potential impact on users. This experiment seeks to evaluate the benefit of augmenting a conflict detection and resolution algorithm to consider a fuel efficient, Zero-Delay Direct-To maneuver, when resolving a given conflict based on either minimum fuel burn or minimum delay. A total of twelve conditions were tested in a fast-time simulation conducted in three airspace regions with mixed aircraft types and light weather. Results show that inclusion of this maneuver has no appreciable effect on the ability of the algorithm to safely detect and resolve conflicts. The results further suggest that enabling the Zero-Delay Direct-To maneuver significantly increases the cumulative fuel burn savings when choosing resolution based on minimum fuel burn while marginally increasing the average delay per resolution.

14 CFR 25.331 - Symmetric maneuvering conditions.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration..., based on a rational pitching control motion vs. time profile, must be established in which the design...

Optimal Orbit Maneuvers with Electrodynamic Tethers

DTIC Science & Technology

2006-06-01

orbital elements , which completely describe a unique orbit ; equinoctial elements are not employed but left for future iterations of the formulation...periods in the maneuver. Follow on work, uch as the transformation of this state vector from classical orbital elements to the quinoctial set of...

Effects of Repeated Valsalva Maneuver Straining on Cardiac and Vasoconstrictive Baroreflex Responses

DTIC Science & Technology

2003-03-01

of blood pressure regulation that differ in men repeatedly exposed to high G acceleration. Am J Physiol Regul Integr Comp Physiol 2001; 280:R947–58. 10...Methods: We tested this hypothesis by measuring cardiac baroreflex responses to carotid baroreceptor stimulation (neck pressures ), and changes in heart rate...hypothesis is the observation that elevated pulse pressures in isolated carotid sinuses of dogs sen- sitized baroreceptor afferent firing (4,5). Elevated arte

Effect of Conflict Resolution Maneuver Execution Delay on Losses of Separation

NASA Technical Reports Server (NTRS)

Cone, Andrew C.

2010-01-01

This paper examines uncertainty in the maneuver execution delay for data linked conflict resolution maneuvers. This uncertainty could cause the previously cleared primary conflict to reoccur or a secondary conflict to appear. Results show that the likelihood of a primary conflict reoccurring during a horizontal conflict resolution maneuver increases with larger initial turn-out angles and with shorter times until loss of separation. There is also a significant increase in the probability of a primary conflict reoccurring when the time until loss falls under three minutes. Increasing horizontal separation by an additional 1.5 nmi lowers the risk, but does not completely eliminate it. Secondary conflicts were shown to have a small probability of occurring in all tested configurations.

Control integration concept for hypersonic cruise-turn maneuvers

NASA Technical Reports Server (NTRS)

Raney, David L.; Lallman, Frederick J.

1992-01-01

Piloting difficulties associated with conducting aircraft maneuvers in hypersonic flight are caused in part by the nonintuitive nature of the aircraft response and the stringent constraints anticipated on allowable angle of attack and dynamic pressure variations. An approach is documented that provides precise, coordinated maneuver control during excursions from a hypersonic cruise flight path and the necessary flight condition constraints. The approach is to achieve specified guidance commands by resolving altitude and cross range errors into a load factor and bank angle command by using a coordinate transformation that acts as an interface between outer and inner loop flight controls. This interface, referred to as a 'resolver', applies constraints on angle of attack and dynamic pressure perturbations while prioritizing altitude regulation over cross range. An unpiloted test simulation, in which the resolver was used to drive inner loop flight controls, produced time histories of responses to guidance commands and atmospheric disturbances at Mach numbers of 6, 10, 15, and 20. Angle of attack and throttle perturbation constraints, combined with high speed flight effects and the desire to maintain constant dynamic pressure, significantly impact the maneuver envelope for a hypersonic vehicle.

Acute myocardial infarction due to spontaneous, localized, acute dissection of the sinus of Valsalva detected by intravascular ultrasound and electrocardiogram-gated computed tomography.

PubMed

Ichihashi, Taku; Ito, Tsuyoshi; Murai, Shunsuke; Ikehara, Noriyuki; Fujita, Hiroshi; Suda, Hisao; Ohte, Nobuyuki

2016-09-01

A 58-year-old man was referred to our hospital because of chest pain. The 12-lead electrocardiogram (ECG) revealed ST-segment elevation in II, III, and a Vf with advanced heart block. Transthoracic echocardiography demonstrated aortic root dilatation at the sinus of Valsalva, moderate aortic regurgitation, and decreased wall motion in the inferior part of the left ventricle. Non-ECG-gated enhanced computed tomography (CT) did not reveal an aortic dissection. The patient underwent emergent coronary angiography, which revealed a severely narrowed ostium of the right coronary artery (RCA). Percutaneous coronary intervention (PCI) was performed under intravascular ultrasound (IVUS) guidance. IVUS images demonstrated an intimal flap extending from the aortic wall to the proximal RCA, suggesting that a periaortic hematoma in the false lumen compressed the ostium of the RCA, leading to acute myocardial infarction. To recover hemodynamic stability, the RCA ostium was stented. Subsequent ECG-gated enhanced CT clearly depicted the entry point and extension of the dissection localized within the sinus of Valsalva. The dissection likely involved the left main coronary artery and an emergent Bentall procedure was performed. Intraoperative findings confirmed an intimal tear and extension of the dissection. Thus, ECG-gated CT can clearly depict the entry site and extension of a dissection occurring in the localized area that cannot be detected by conventional CT.

Transcranial Doppler and transesophageal echocardiography: comparison of both techniques and prospective clinical relevance of transcranial Doppler in patent foramen ovale detection.

PubMed

Caputi, Luigi; Carriero, Maria Rita; Falcone, Chiara; Parati, Eugenio; Piotti, Patrizia; Materazzo, Carlo; Anzola, Gian Paolo

2009-01-01

Patent foramen ovale (PFO) has been investigated in several conditions apart from cryptogenic ischemic stroke. Contrast transesophageal echocardiography (cTEE) is the gold standard for the diagnosis, although it has some known limitations. Contrast transcranial Doppler (cTCD) allows a semiquantitative estimation of right-to-left shunt (RLS) volume. The aims of our study were to confirm the diagnostic accuracy of cTCD in PFO diagnosis and to compare the abilities of cTCD and cTEE to detect a RLS and PFO, respectively, under normal breathing. The latter could represent an important feature for its clinical significance. A total of 100 consecutive patients (59 women and 41 men, age 46 +/- 12 years) were evaluated after stabilized ischemic stroke/transient ischemic attack, migraine, and lacunae, and before neurosurgery in sitting position. All patients undertook cTEE and cTCD, at rest and under Valsalva maneuver (VM). cTEE under VM was the reference standard. A categorization of patients and a semiquantitative cTCD classification were proposed. In all, 63 of 100 patients had PFO diagnosed by cTEE. A general concordance of up to 90% between both techniques was found. cTCD sensitivity and specificity were 96.8% and 78.4%, respectively. In 17 of 100 patients with cTEE-proven PFO under VM, cTCD and cTEE detected RLS at rest in 75% (95% confidence interval [CI] 62%-85%) and 48% (95% CI 35%-61%) of cases, respectively (P < .001). cTEE disclosed RLS at rest in about 71% (95% CI 9%-42%) of cTCDs showing a "shower-curtain" pattern and only in about 22% (95% CI 52%-85%) of those cTCDs without that pattern. In diagnosing PFO, cTCD has a good accuracy compared with cTEE. To detect a RLS at rest, cTCD appears to be more sensitive than cTEE. The latter resulted positive under normal breathing, mostly in cases of significant RLS at cTCD. Our results point out the impact of cTCD in the evaluation of RLS volume, thus aiding, in association with the anatomic details by cTEE, in the

Study on zigzag maneuver characteristics of V-U very large crude oil (VLCC) tankers

NASA Astrophysics Data System (ADS)

Jaswar, Maimun, A.; Wahid, M. A.; Priyanto, A.; Zamani, Pauzi, Saman

2012-06-01

The Department of Marine Technology at the Faculty of Mechanical Engineering, University Teknologi Malaysia has recently developed an Ship Maneuverability tool which intends to upgrade student's level understanding the application of fluid dynamic on interaction between hull, propeller, and rudder during maneuvering. This paper discusses zigzag maneuver for conventional Very Large Crude Oil (VLCC) ships with the same principal dimensions but different stern flame shape. 10/10 zigzag maneuver characteristics of U and V types of VLCC ships are investigated. Simulation results for U-type show a good agreement with the experimental data, but V-type not good agreement with experimental one. Further study on zigzag maneuver characteristics are required.

Validation of On-Orbit Methodology for the Assessment of Cardiac Function and Changes in the Circulating Volume Using "Braslet-M" Occlusion Cuffs

NASA Technical Reports Server (NTRS)

Hamilton, D. R.; Sargsyan, A. E.; Garcia, K. M.; Ebert, D.; Feiveson, A. H.; Alferova, I. V.; Dulchavsky, S. A.; Matveev, V. P.; Bogomolov, V. V.; Duncan, J. M.

2011-01-01

BACKGROUND: The transition to microgravity eliminates the hydrostatic gradients in the vascular system. The resulting fluid redistribution commonly manifests as facial edema, engorgement of the external neck veins, nasal congestion, and headache. This experiment examined the responses to modified Valsalva and Mueller maneuvers as measured by cardiac and vascular ultrasound in a baseline microgravity steady state, and under the influence of thigh occlusion cuffs (Braslet cuffs). METHODS: Nine International Space Station crewmember subjects (Expeditions 16 - 20) were examined in 15 experiment sessions 101 46 days after launch (mean SD; 33 - 185). 27 cardiac and vascular parameters were obtained under three respiratory conditions (baseline, Valsalva, and Mueller) before and after tightening of the Braslet cuffs for a total of 162 data points per session. The quality of cardiac and vascular ultrasound examinations was assured through remote monitoring and guidance by Investigators from the NASA Telescience Center in Houston, TX, USA. RESULTS: Fourteen of the 81 measured conditions were significantly different with Braslet application and were apparently related to cardiac preload reduction or increase in the venous volume sequestered in the lower extremity. These changes represented 10 of the 27 parameters measured. In secondary analysis, 7 of the 27 parameters were found to respond differently to respiratory maneuvers depending on the presence or absence of thigh compression, with a total of 11 differences. CONCLUSIONS: Acute application of Braslet occlusion cuffs causes lower extremity fluid sequestration and exerts proportionate measurable effects on cardiac performance in microgravity. Ultrasound techniques measuring the hemodynamic effects of thigh cuffs in combination with respiratory maneuvers may serve as an effective tool in determining the volume status of a cardiac or hemodynamically compromised patient in microgravity.

Adaptive ISAR Imaging of Maneuvering Targets Based on a Modified Fourier Transform.

PubMed

Wang, Binbin; Xu, Shiyou; Wu, Wenzhen; Hu, Pengjiang; Chen, Zengping

2018-04-27

Focusing on the inverse synthetic aperture radar (ISAR) imaging of maneuvering targets, this paper presents a new imaging method which works well when the target's maneuvering is not too severe. After translational motion compensation, we describe the equivalent rotation of maneuvering targets by two variables-the relative chirp rate of the linear frequency modulated (LFM) signal and the Doppler focus shift. The first variable indicates the target's motion status, and the second one represents the possible residual error of the translational motion compensation. With them, a modified Fourier transform matrix is constructed and then used for cross-range compression. Consequently, the imaging of maneuvering is converted into a two-dimensional parameter optimization problem in which a stable and clear ISAR image is guaranteed. A gradient descent optimization scheme is employed to obtain the accurate relative chirp rate and Doppler focus shift. Moreover, we designed an efficient and robust initialization process for the gradient descent method, thus, the well-focused ISAR images of maneuvering targets can be achieved adaptively. Human intervention is not needed, and it is quite convenient for practical ISAR imaging systems. Compared to precedent imaging methods, the new method achieves better imaging quality under reasonable computational cost. Simulation results are provided to validate the effectiveness and advantages of the proposed method.

Implementation of a Collision Probability Prediction Technique for Constellation Maneuver Planning

NASA Technical Reports Server (NTRS)

Concha, Marco a.

2007-01-01

On March 22, 2006, the Space Technology 5 (ST5) constellation spacecraft were successfully delivered to orbit by a Pegasus XI, launch vehicle. An unexpected relative motion experienced by the constellation after orbit insertion brought about a problem. Soon after launch the observed relative position of the inert rocket body was between the leading and the middle spacecraft within the constellation. The successful planning and execution of an orbit maneuver that would create a fly-by of the rocket body was required to establish the.formation. This maneuver would create a close approach that needed to conform to predefined collision probability requirements. On April 21, 2006, the ST5 "155" spacecraft performed a large orbit maneuver and successfully passed the inert Pegasus 3rd Stage Rocket Body on April 30, 2006 15:20 UTC at a distance of 2.55 km with a Probability of Collision of less than 1.0E-06. This paper will outline the technique that was implemented to establish the safe planning and execution of the fly-by maneuver. The method makes use of Gaussian distribution models of state covariance to determine underlying probabilities of collision that arise under low velocity encounters. Specific numerical examples used for this analysis are discussed in detail. The mechanics of this technique are explained to foster deeper understanding of the concepts presented and to improve existing processes for use in future constellation maneuver planning.

An Analytical Solution for Yaw Maneuver Optimization on the International Space Station and Other Orbiting Space Vehicles

NASA Technical Reports Server (NTRS)

Dobrinskaya, Tatiana

2015-01-01

This paper suggests a new method for optimizing yaw maneuvers on the International Space Station (ISS). Yaw rotations are the most common large maneuvers on the ISS often used for docking and undocking operations, as well as for other activities. When maneuver optimization is used, large maneuvers, which were performed on thrusters, could be performed either using control moment gyroscopes (CMG), or with significantly reduced thruster firings. Maneuver optimization helps to save expensive propellant and reduce structural loads - an important factor for the ISS service life. In addition, optimized maneuvers reduce contamination of the critical elements of the vehicle structure, such as solar arrays. This paper presents an analytical solution for optimizing yaw attitude maneuvers. Equations describing pitch and roll motion needed to counteract the major torques during a yaw maneuver are obtained. A yaw rate profile is proposed. Also the paper describes the physical basis of the suggested optimization approach. In the obtained optimized case, the torques are significantly reduced. This torque reduction was compared to the existing optimization method which utilizes the computational solution. It was shown that the attitude profiles and the torque reduction have a good match for these two methods of optimization. The simulations using the ISS flight software showed similar propellant consumption for both methods. The analytical solution proposed in this paper has major benefits with respect to computational approach. In contrast to the current computational solution, which only can be calculated on the ground, the analytical solution does not require extensive computational resources, and can be implemented in the onboard software, thus, making the maneuver execution automatic. The automatic maneuver significantly simplifies the operations and, if necessary, allows to perform a maneuver without communication with the ground. It also reduces the probability of command

32 CFR 644.137 - Maneuver agreements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... planning and acquires rights to use land and other facilities for Department of the Army exercises. The... and, after the maneuver is completed, will be responsible for negotiating restoration settlements and... director at field level whereby the command will assume responsibility for settlement of real estate...

Fuel optimal maneuvers of spacecraft about a circular orbit

NASA Technical Reports Server (NTRS)

Carter, T. E.

1982-01-01

Fuel optimal maneuvers of spacecraft relative to a body in circular orbit are investigated using a point mass model in which the magnitude of the thrust vector is bounded. All nonsingular optimal maneuvers consist of intervals of full thrust and coast and are found to contain at most seven such intervals in one period. Only four boundary conditions where singular solutions occur are possible. Computer simulation of optimal flight path shapes and switching functions are found for various boundary conditions. Emphasis is placed on the problem of soft rendezvous with a body in circular orbit.

A Computer Simulation of the System-Wide Effects of Parallel-Offset Route Maneuvers

NASA Technical Reports Server (NTRS)

Lauderdale, Todd A.; Santiago, Confesor; Pankok, Carl

2010-01-01

Most aircraft managed by air-traffic controllers in the National Airspace System are capable of flying parallel-offset routes. This paper presents the results of two related studies on the effects of increased use of offset routes as a conflict resolution maneuver. The first study analyzes offset routes in the context of all standard resolution types which air-traffic controllers currently use. This study shows that by utilizing parallel-offset route maneuvers, significant system-wide savings in delay due to conflict resolution of up to 30% are possible. It also shows that most offset resolutions replace horizontal-vectoring resolutions. The second study builds on the results of the first and directly compares offset resolutions and standard horizontal-vectoring maneuvers to determine that in-trail conflicts are often more efficiently resolved by offset maneuvers.

Quantifying rapid changes in cardiovascular state with a moving ensemble average.

PubMed

Cieslak, Matthew; Ryan, William S; Babenko, Viktoriya; Erro, Hannah; Rathbun, Zoe M; Meiring, Wendy; Kelsey, Robert M; Blascovich, Jim; Grafton, Scott T

2018-04-01

MEAP, the moving ensemble analysis pipeline, is a new open-source tool designed to perform multisubject preprocessing and analysis of cardiovascular data, including electrocardiogram (ECG), impedance cardiogram (ICG), and continuous blood pressure (BP). In addition to traditional ensemble averaging, MEAP implements a moving ensemble averaging method that allows for the continuous estimation of indices related to cardiovascular state, including cardiac output, preejection period, heart rate variability, and total peripheral resistance, among others. Here, we define the moving ensemble technique mathematically, highlighting its differences from fixed-window ensemble averaging. We describe MEAP's interface and features for signal processing, artifact correction, and cardiovascular-based fMRI analysis. We demonstrate the accuracy of MEAP's novel B point detection algorithm on a large collection of hand-labeled ICG waveforms. As a proof of concept, two subjects completed a series of four physical and cognitive tasks (cold pressor, Valsalva maneuver, video game, random dot kinetogram) on 3 separate days while ECG, ICG, and BP were recorded. Critically, the moving ensemble method reliably captures the rapid cyclical cardiovascular changes related to the baroreflex during the Valsalva maneuver and the classic cold pressor response. Cardiovascular measures were seen to vary considerably within repetitions of the same cognitive task for each individual, suggesting that a carefully designed paradigm could be used to capture fast-acting event-related changes in cardiovascular state. © 2017 Society for Psychophysiological Research.

Investigation of prefrontal cerebral hemodynamics during quantitative autonomic testing using NIRS (Conference Presentation)

NASA Astrophysics Data System (ADS)

Phillips, Zephaniah; Paik, Seung-Ho; Kim, Yoohwan; Kim, Byung-Jo; Choi, Youngwoon; Kim, Beop-Min

2017-02-01

In this work, we analyzed the clinical applicability of NIRS for use during Quantitative Autonomic Testing (QAT). QAT is a protocol consisting of deep breathing, Valsalva maneuver, and tilt table examination. It is used to diagnose a patient with disorders of the autonomic nervous system (ANS). Disorders of ANS includes orthostatic hyper/hypotension, vasovagal syncope, and postural orthostatic tachycardia syndrome. The results of QAT are typically analyzed with the use of blood pressure and heart rate data, however these metrics may be influenced by factors such as arrhythmia, making the data interpretation and diagnosis difficult for clinicians. We tested our custom built 108-channel NIRS probe on 26 elderly patients during the QAT protocol with various ANS disorders. We found that prefrontal cerebral oxygenation correlated well with blood pressure and heart rate changes for all three tasks, making it a clinically feasible tool for observing ANS functionality. During the Valsalva maneuver, we observed a longer delayed and lower amplitude response of cerebral oxygenation to the prefrontal area in orthostatic intolerant patients. During the tilt table examination, we saw a larger response in cerebral oxygenation and less equal transient cerebral oxygenation during tilt up and tilt down in tilt table examinations that were positive (unhealthy), compared to tilt table examinations that were negative (healthy). Overall, our study showcases NIRS as an enhanced tool for understanding ANS disorders.

GTARG - THE TOPEX/POSEIDON GROUND TRACK MAINTENANCE MANEUVER TARGETING PROGRAM

NASA Technical Reports Server (NTRS)

Shapiro, B. E.

1994-01-01

GTARG, The TOPEX/POSEIDON Ground Track Maintenance Maneuver Targeting Program, was developed to assist in the designing of orbit maintenance maneuvers for the TOPEX/POSEIDON satellite. These maneuvers ensure that the ground track is kept within 1 km of an approximately 9.9 day exact repeat pattern. Targeting strategies used by GTARG will either maximize the time between maneuvers (longitude targeting) or force control band exit to occur at specified intervals (time targeting). A runout mode allows for ground track propagation without targeting. The analytic mean-element propagation algorithm used in GTARG includes all perturbations that are known to cause significant variations in the satellite ground track. These include earth oblateness, luni-solar gravity, and drag, as well as the thrust due to impulsive maneuvers and unspecified along-track satellite fixed forces. Merson's extension of Grove's theory is used for the computation of the geopotential field. Kaula's disturbing function is used to attain the luni-solar gravitational perturbations. GTARG includes a satellite unique drag model which incorporates an approximate mean orbital Jacchia-Roberts atmosphere and a variable mean area model. Error models include uncertainties due to orbit determination, maneuver execution, drag unpredictability, as well as utilization of the knowledge of along-track satellite fixed forces. Maneuver Delta-v magnitudes are targeted to precisely maintain either the unbiased ground track itself, or a comfortable (3 sigma) error envelope about the unbiased ground track. GTARG is written in VAX-FORTRAN for DEC VAX Series computers running VMS. GTARG output is provided in two forms: an executive report summary which is in tabular form, and a plot file which is formatted as EZPLOT input namelists. Although the EZPLOT program and documentation are included with GTARG, EZPLOT requires PGPLOT, which was written by the California Institute of Technology Astronomy Department. (For non

Detail view of the "underside" of the Orbiter Maneuvering/Reaction Control ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail view of the "underside" of the Orbiter Maneuvering/Reaction Control Systems pod looking at the two spherical propellant tanks for the Reaction Control System, and the elongated propellant tanks for the Orbiter Maneuvering System. This view was taken at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Projectile Roll Dynamics and Control With a Low-Cost Skid-to-Turn Maneuver System

DTIC Science & Technology

2013-03-01

scheme. The mechatronics of the maneuver system was provided. The suitability of this design for survival at gun launch was assessed through...Projectile Roll Dynamics and Control With a Low-Cost Skid-to-Turn Maneuver System by Frank Fresconi, Ilmars Celmins, Mark Ilg, and James...5069 ARL-TR-6363 March 2013 Projectile Roll Dynamics and Control With a Low-Cost Skid-to-Turn Maneuver System Frank Fresconi, Ilmars

Kalman filtering applied to real-time monitoring of apogee maneuvers

NASA Technical Reports Server (NTRS)

Deboer, Frederic; Barbier, Christian

1993-01-01

Part of the Space Mathematics Division in CNES, the Flight Dynamics Center provides attitude and orbit determinations and maneuvers during the Launch and Early Operation Phase (LEOP) of geostationary satellites. Orbit determination is based on a Kalman filter method; when the 2 GHz CNES/NASA network is used, Doppler measurements are available and allow orbit determination during the apogee maneuvers. This method was used for TELE-X and TDF 2 LEOP (3-axis controlled satellites) and also for TELECOM 2 and HISPASAT (spun satellites): it enables us to follow the evolution of the maneuver and gives out a quite accurate estimation of the reached orbit. In this paper, we briefly describe the dynamic models of the orbit evolution in both cases, '3-axis' and 'inertial' thrust. Then, we present the results obtained for each case. Afterwards, we present some cases to show the robustness of the filter.

A Real-Time Robust Method to Detect BeiDou GEO/IGSO Orbital Maneuvers

PubMed Central

Huang, Guanwen; Qin, Zhiwei; Zhang, Qin; Wang, Le; Yan, Xingyuan; Fan, Lihong; Wang, Xiaolei

2017-01-01

The frequent maneuvering of BeiDou Geostationary Orbit (GEO) and Inclined Geosynchronous Orbit (IGSO) satellites affects the availability of real-time orbit, and decreases the accuracy and performance of positioning, navigation and time (PNT) services. BeiDou satellite maneuver information cannot be obtained by common users. BeiDou broadcast ephemeris is the only indicator of the health status of satellites, which are broadcast on an hourly basis, easily leading to ineffective observations. Sometimes, identification errors of satellite abnormity also appear in the broadcast ephemeris. This study presents a real-time robust detection method for a satellite orbital maneuver with high frequency and high reliability. By using the broadcast ephemeris and pseudo-range observations, the time discrimination factor and the satellite identification factor were defined and used for the real-time detection of start time and the pseudo-random noise code (PRN) of satellites was used for orbital maneuvers. Data from a Multi-GNSS Experiment (MGEX) was collected and analyzed. The results show that the start time and the PRN of the satellite orbital maneuver could be detected accurately in real time. In addition, abnormal start times and satellite abnormities caused by non-maneuver factors also could be detected using the proposed method. The new method not only improves the utilization of observations for users with the data effective for about 92 min, but also promotes the reliability of real-time PNT services. PMID:29186058

A Real-Time Robust Method to Detect BeiDou GEO/IGSO Orbital Maneuvers.

PubMed

Huang, Guanwen; Qin, Zhiwei; Zhang, Qin; Wang, Le; Yan, Xingyuan; Fan, Lihong; Wang, Xiaolei

2017-11-29

The frequent maneuvering of BeiDou Geostationary Orbit (GEO) and Inclined Geosynchronous Orbit (IGSO) satellites affects the availability of real-time orbit, and decreases the accuracy and performance of positioning, navigation and time (PNT) services. BeiDou satellite maneuver information cannot be obtained by common users. BeiDou broadcast ephemeris is the only indicator of the health status of satellites, which are broadcast on an hourly basis, easily leading to ineffective observations. Sometimes, identification errors of satellite abnormity also appear in the broadcast ephemeris. This study presents a real-time robust detection method for a satellite orbital maneuver with high frequency and high reliability. By using the broadcast ephemeris and pseudo-range observations, the time discrimination factor and the satellite identification factor were defined and used for the real-time detection of start time and the pseudo-random noise code (PRN) of satellites was used for orbital maneuvers. Data from a Multi-GNSS Experiment (MGEX) was collected and analyzed. The results show that the start time and the PRN of the satellite orbital maneuver could be detected accurately in real time. In addition, abnormal start times and satellite abnormities caused by non-maneuver factors also could be detected using the proposed method. The new method not only improves the utilization of observations for users with the data effective for about 92 min, but also promotes the reliability of real-time PNT services.

Comparing Models of Spontaneous Variations, Maneuvers and Indexes to Assess Dynamic Cerebral Autoregulation.

PubMed

Chacón, Max; Noh, Sun-Ho; Landerretche, Jean; Jara, José L

2018-01-01

We analyzed the performance of linear and nonlinear models to assess dynamic cerebral autoregulation (dCA) from spontaneous variations in healthy subjects and compared it with the use of two known maneuvers to abruptly change arterial blood pressure (BP): thigh cuffs and sit-to-stand. Cerebral blood flow velocity and BP were measured simultaneously at rest and while the maneuvers were performed in 20 healthy subjects. To analyze the spontaneous variations, we implemented two types of models using support vector machine (SVM): linear and nonlinear finite impulse response models. The classic autoregulation index (ARI) and the more recently proposed model-free ARI (mfARI) were used as measures of dCA. An ANOVA analysis was applied to compare the different methods and the coefficient of variation was calculated to evaluate their variability. There are differences between indexes, but not between models and maneuvers. The mfARI index with the sit-to-stand maneuver shows the least variability. Support vector machine modeling of spontaneous variation with the mfARI index could be used for the assessment of dCA as an alternative to maneuvers to introduce large BP fluctuations.

Craniocervical Pneumatization

PubMed Central

Quigley, Alan James; Shannon, Helen

2013-01-01

Craniocervical bony pneumatization is a rare finding, with limited numbers of cases reported in the literature. It is thought to be linked to Eustachian tube dysfunction and a ball valve mechanism, and has a link with recurrent Valsalva maneuvers. We report a case of pneumatization of the occiput, atlas (C1) and axis (C2) in a patient with extensive ENT (Ear, Nose and Throat) surgical history who presented following a fall. Plain film, CT and MRI images are presented. PMID:24421950

Display dimensionality and conflict geometry effects on maneuver preferences for resolving in-flight conflicts.

PubMed

Thomas, Lisa C; Wickens, Christopher D

2008-08-01

Two experiments explored the effects of display dimensionality, conflict geometry, and time pressure on pilot maneuvering preferences for resolving en route conflicts. With the presence of a cockpit display of traffic information (CDTI) that provides graphical airspace information, pilots can use a variety of conflict resolution maneuvers in response to how they perceive the conflict. Inconsistent preference findings from previous research on conflict resolution using CDTIs may be attributable to inherent ambiguities in 3-D perspective displays and/or a limited range of conflict geometries. Pilots resolved predicted conflicts using CDTIs with three levels of display dimensionality; the first had two 2-D orthogonal views, the second depicted the airspace in two alternating 3-D perspective views, and the third had a pilot-controlled swiveling viewpoint. Pilots demonstrated the same preferences that have been observed in previous research for vertical over lateral maneuvers in low workload and climbs over descents for level-flight conflicts. With increasing workload the two 3-D perspective displays, but not the 2-D displays, resulted in an increased preference for lateral over vertical maneuvers. Increased time pressure resulted in increased vertical maneuvers, an effect again limited to the two 3-D perspective displays. Resolution preferences were more affected by workload and time pressure when the 3-D perspective displays were used, as compared with the 2-D displays, although overall preferences were milder than in previous studies. Investigating maneuver preferences using the strategic flight planning paradigm employed in this study may be the key to better ensure pilot acceptance of computer-generated resolution maneuvers.

CFD investigations of the aerodynamics of vehicle overtaking maneuvers

NASA Astrophysics Data System (ADS)

Uddin, Mesbah; Chellaram, Arune Dhiren; Robinson, Austin Clay

2017-06-01

When two vehicle bodies are involved in a passing maneuver, interesting and intricate aerodynamic interactions occur between them. Such passing maneuvers are very important in racing and have been an area of active interest in motorsports for quite some time. The existing literature shows only a few studies in this area, and, as such, very little is known about the complex aerodynamics of racing in proximity. This paper presents a Computational Fluid Dynamics (CFD) methodology capable of describing the transient effects that occur in this scenario. This is achieved by simulating two tandem simplified vehicle bodies, the Ahmed body, which were placed in a virtual wind tunnel. One Ahmed body was kept stationary, while the other was allowed to move in the longitudinal direction with a relatively low velocity. In order to achieve reliable CFD results when one of the solid objects is moving, a new meshing methodology, called the overset mesh model, was implemented in the CFD process. The simulations were run using Star CCM+, a commercial finite-volume CFD program, in which the unsteady Reynolds Averaged Navier-Stokes (URANS) solver was applied. The CFD results are compared against fully transient and quasi-steady-state experimental results where encouraging correlations between the CFD and experiments are observed. The veracity of the CFD work presented in this paper provides significant insight into the complex aerodynamics of a passing maneuver, and lays the foundation for further analysis in this area using more complex vehicle shapes and more complex tandem racing or passing maneuvers at a yaw angle.

PM Science Working Group Meeting on Spacecraft Maneuvers

NASA Technical Reports Server (NTRS)

Parkinson, Claire L.

1997-01-01

The EOS PM Science Working Group met on May 6, 1997, to examine the issue of spacecraft maneuvers. The meeting was held at NASA Goddard Space Flight Center and was attended by the Team Leaders of all four instrument science teams with instruments on the PM-1 spacecraft, additional representatives from each of the four teams, the PM Project management, and random others. The meeting was chaired by the PM Project Scientist and open to all. The meeting was called in order to untangle some of the concerns raised over the past several months regarding whether or not the PM-1 spacecraft should undergo spacecraft maneuvers to allow the instruments to obtain deep-space views. Two of the Science Teams, those for the Moderate-Resolution Imaging Spectroradiometer (MODIS) and the Clouds and the Earth's Radiant Energy System (CERES), had strongly expressed the need for deep-space views in order to calibrate their instruments properly and conveniently. The other two teams, those for the Advanced Microwave Scanning Radiometer (AMSR-E) and the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU), and the Humidity Sounder for Brazil (HSB), had expressed concerns that the maneuvers involve risks to the instruments and undesired gaps in the data sets.

X-31 in flight - Mongoose Maneuver

NASA Technical Reports Server (NTRS)

1995-01-01

Two X-31 Enhanced Fighter Maneuverability (EFM) demonstrators were flown at the Rockwell International facility, Palmdale, California, and the NASA Dryden Flight Research Center, Edwards, California, to obtain data that may apply to the design of highly-maneuverable next-generation fighters. The program had its first flight on October 11, 1990, in Palmdale; it ended in June 1995. The X-31 program demonstrated the value of thrust vectoring (directing engine exhaust flow) coupled with advanced flight control systems, to provide controlled flight during close-in air combat at very high angles of attack. The result of this increased maneuverability is an aircraft with a significant advantage over conventional fighters. 'Angle-of-attack' (alpha) is an engineering term to describe the angle of an aircraft body and wings relative to its actual flight path. During maneuvers, pilots often fly at extreme angles of attack -- with the nose pitched up while the aircraft continues in its original direction. This can lead to loss of control and result in the loss of the aircraft, pilot or both. Three thrust-vectoring paddles made of graphite epoxy mounted on the exhaust nozzle of the X-31 aircraft directed the exhaust flow to provide control in pitch (up and down) and yaw (right and left) to improve control. The paddles can sustain heat of up to 1,500 degrees centigrade for extended periods of time. In addition the X-31 aircraft were configured with movable forward canards and fixed aft strakes. The canards were small wing-like structures set on the wing line between the nose and the leading edge of the wing. The strakes were set on the same line between the trailing edge of the wing and the engine exhaust. Both supplied additional control in tight maneuvering situations. The X-31 research program produced technical data at high angles of attack. This information is giving engineers and aircraft designers a better understanding of aerodynamics, effectiveness of flight controls

Study of the Characteristics of Pulmonary Trunk in Pulmonary Hypertension Secondary to Left Heart Disease Using Pressure–Velocity Loops (PU-Loops)

PubMed Central

Hanya, Shizuo; Yoshii, Kengo; Sugawara, Motoaki

2017-01-01

Objectives: Although pulmonary hypertension (PH) caused by left heart disease (PH-LHD) is more common in PH, little is known about its properties of pulmonary artery (PA) in PH-LHD. The purpose of this study was to measure pulmonary regional pulse wave velocity (PWV) and to quantify the magnitude of reflected waves in patients with PH-LHD by the analysis of the pressure–velocity loops (PU-loop). Methods: High-fidelity PA pressure (Pm) and PA velocity (Vm) were measured in 11 subjects with PH-LHD (mean Pm>25 mmHg), 1 subject with atrial septal defect (ASD) without PH and 12 control subjects, using multisensor catheters. PWV was calculated as the slope of the initial part of the PU-loop in early systole. The similarity in the shapes of the pressure and flow velocity waveforms over one PU-loop was quantified as the magnitude of reflected wave by calculating the standard error of the estimate (Sy/x) from linear regression analysis between Pm and corresponding Vm. PWV and Sy/x during a Valsalva maneuver (VM) were also assessed in nine control subjects. Results: The contour of PU-loop was so characteristic between control and PH-LHD. Max. PWV (349 cm/s) was recorded in PH-LHD and min. PWV (111 cm/s) was recorded in ASD. VM increased Pm (12 [7–15] mmHg vs. 50 [18–110] mmHg; p=0.009) and PWV (200 [148–238] cm/s vs. 260 [192–306] cm/s; p=0.009) significantly without significant increase of Sy/x (19.6 [12.7–28.9]% vs. 28.2 [19.3–40.7]%; p=0.079). Although Sy/x was significantly higher in PH-LHD than in control and ASD (31.0 [14.3–36.3]% vs. 17.5 [8.4–28.9]%; p=0.009, ASD: 18.2%) , no significant difference was found in PWV between PH-LHD and control (269 [159–349] cm/s vs. 203 [154–289] cm/s; p=0.089). Conclusions: 1) The magnitude of wave reflection was elevated in PH-LHD significantly as compared with control and ASD. 2) Despite the significant increase in PA-PWV caused by abrupt elevation in Pm during VM in control, chronic elevation in Pm did

Real-time optimal guidance for orbital maneuvering.

NASA Technical Reports Server (NTRS)

Cohen, A. O.; Brown, K. R.

1973-01-01

A new formulation for soft-constraint trajectory optimization is presented as a real-time optimal feedback guidance method for multiburn orbital maneuvers. Control is always chosen to minimize burn time plus a quadratic penalty for end condition errors, weighted so that early in the mission (when controllability is greatest) terminal errors are held negligible. Eventually, as controllability diminishes, the method partially relaxes but effectively still compensates perturbations in whatever subspace remains controllable. Although the soft-constraint concept is well-known in optimal control, the present formulation is novel in addressing the loss of controllability inherent in multiple burn orbital maneuvers. Moreover the necessary conditions usually obtained from a Bolza formulation are modified in this case so that the fully hard constraint formulation is a numerically well behaved subcase. As a result convergence properties have been greatly improved.

Integrated detection, estimation, and guidance in pursuit of a maneuvering target

NASA Astrophysics Data System (ADS)

Dionne, Dany

The thesis focuses on efficient solutions of non-cooperative pursuit-evasion games with imperfect information on the state of the system. This problem is important in the context of interception of future maneuverable ballistic missiles. However, the theoretical developments are expected to find application to a broad class of hybrid control and estimation problems in industry. The validity of the results is nevertheless confirmed using a benchmark problem in the area of terminal guidance. A specific interception scenario between an incoming target with no information and a single interceptor missile with noisy measurements is analyzed in the form of a linear hybrid system subject to additive abrupt changes. The general research is aimed to achieve improved homing accuracy by integrating ideas from detection theory, state estimation theory and guidance. The results achieved can be summarized as follows. (i) Two novel maneuver detectors are developed to diagnose abrupt changes in a class of hybrid systems (detection and isolation of evasive maneuvers): a new implementation of the GLR detector and the novel adaptive- H0 GLR detector. (ii) Two novel state estimators for target tracking are derived using the novel maneuver detectors. The state estimators employ parameterized family of functions to described possible evasive maneuvers. (iii) A novel adaptive Bayesian multiple model predictor of the ballistic miss is developed which employs semi-Markov models and ideas from detection theory. (iv) A novel integrated estimation and guidance scheme that significantly improves the homing accuracy is also presented. The integrated scheme employs banks of estimators and guidance laws, a maneuver detector, and an on-line governor; the scheme is adaptive with respect to the uncertainty affecting the probability density function of the filtered state. (v) A novel discretization technique for the family of continuous-time, game theoretic, bang-bang guidance laws is introduced. The

Maneuver Acoustic Flight Test of the Bell 430 Helicopter

NASA Technical Reports Server (NTRS)

Watts, Michael E.; Snider, Royce; Greenwood, Eric; Baden, Joel

2012-01-01

A cooperative flight test by NASA, Bell Helicopter and the U.S. Army to characterize the steady state acoustics and measure the maneuver noise of a Bell Helicopter 430 aircraft was accomplished. The test occurred during June/July, 2011 at Eglin Air Force Base, Florida. This test gathered a total of 410 data points over 10 test days and compiled an extensive data base of dynamic maneuver measurements. Three microphone configurations with up to 31 microphones in each configuration were used to acquire acoustic data. Aircraft data included DGPS, aircraft state and rotor state information. This paper provides an overview of the test.

Application of hybrid methodology to rotors in steady and maneuvering flight

NASA Astrophysics Data System (ADS)

Rajmohan, Nischint

Helicopters are versatile flying machines that have capabilities that are unparalleled by fixed wing aircraft, such as operating in hover, performing vertical takeoff and landing on unprepared sites. This makes their use especially desirable in military and search-and-rescue operations. However, modern helicopters still suffer from high levels of noise and vibration caused by the physical phenomena occurring in the vicinity of the rotor blades. Therefore, improvement in rotorcraft design to reduce the noise and vibration levels requires understanding of the underlying physical phenomena, and accurate prediction capabilities of the resulting rotorcraft aeromechanics. The goal of this research is to study the aeromechanics of rotors in steady and maneuvering flight using hybrid Computational Fluid Dynamics (CFD) methodology. The hybrid CFD methodology uses the Navier-Stokes equations to solve the flow near the blade surface but the effect of the far wake is computed through the wake model. The hybrid CFD methodology is computationally efficient and its wake modeling approach is nondissipative making it an attractive tool to study rotorcraft aeromechanics. Several enhancements were made to the CFD methodology and it was coupled to a Computational Structural Dynamics (CSD) methodology to perform a trimmed aeroelastic analysis of a rotor in forward flight. The coupling analyses, both loose and tight were used to identify the key physical phenomena that affect rotors in different steady flight regimes. The modeling enhancements improved the airloads predictions for a variety of flight conditions. It was found that the tightly coupled method did not impact the loads significantly for steady flight conditions compared to the loosely coupled method. The coupling methodology was extended to maneuvering flight analysis by enhancing the computational and structural models to handle non-periodic flight conditions and vehicle motions in time accurate mode. The flight test

Know Before You Do: Anticipating Maneuvers via Learning Temporal Driving Models

DTIC Science & Technology

2015-04-01

features/index.htm. Accessed: 2014-09-30. [3] Google self driving car . http://en.wikipedia.org/wiki/ Google driverless car . Accessed: 2014-10-11. [4...and outside the car , GPS, and speed information, with lane and driving maneuver annotations. II. RELATED WORK Assistive features for vehicles . Recent...made driving safer over the last decade. They prepare vehicles for unsafe road conditions and alert drivers if they perform a dangerous maneuver

Rapid rotational/translational maneuvering experiments of a flexible steel beam

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Yang, Li-Farn; Huanag, Jen-Kuang; Macauley, Richard

1989-01-01

Future space manipulators may need translational base motion to expand the access region of a manipulator. An experiment was conducted to demonstrate slewing of flexible structures with coupled rotational and translational axes while simultaneously suppressing vibrational motion during the maneuver. In the experiment, a flexible steel beam carried by a translational cart was maneuvered by an active controller to perform position-control tasks. Experimental results are presented to show how the flexibility of the steel beam influences the multi-input multi-output feedback controller.

Effects of automobile steering characteristics on driver/vehicle system performance in discrete maneuvers

NASA Technical Reports Server (NTRS)

Klein, R. H.; Mcruer, D. T.

1975-01-01

A series of discrete maneuver tasks were used to evaluate the effects of steering gain and directional mode dynamic parameters on driver/vehicle responses. The importance and ranking of these parameters were evaluated through changes in subjective driver ratings and performance measures obtained from transient maneuvers such as a double lane change, an emergency lane change, and an unexpected obstacle. The unexpected obstacle maneuver proved more sensitive to individual driver differences than to vehicle differences. Results were based on full scale tests with an experienced test driver evaluating many different dynamic configurations plus seventeen ordinary drivers evaluating six key configurations.

Autonomous Guidance Strategy for Spacecraft Formations and Reconfiguration Maneuvers

NASA Astrophysics Data System (ADS)

Wahl, Theodore P.

A guidance strategy for autonomous spacecraft formation reconfiguration maneuvers is presented. The guidance strategy is presented as an algorithm that solves the linked assignment and delivery problems. The assignment problem is the task of assigning the member spacecraft of the formation to their new positions in the desired formation geometry. The guidance algorithm uses an auction process (also called an "auction algorithm''), presented in the dissertation, to solve the assignment problem. The auction uses the estimated maneuver and time of flight costs between the spacecraft and targets to create assignments which minimize a specific "expense'' function for the formation. The delivery problem is the task of delivering the spacecraft to their assigned positions, and it is addressed through one of two guidance schemes described in this work. The first is a delivery scheme based on artificial potential function (APF) guidance. APF guidance uses the relative distances between the spacecraft, targets, and any obstacles to design maneuvers based on gradients of potential fields. The second delivery scheme is based on model predictive control (MPC); this method uses a model of the system dynamics to plan a series of maneuvers designed to minimize a unique cost function. The guidance algorithm uses an analytic linearized approximation of the relative orbital dynamics, the Yamanaka-Ankersen state transition matrix, in the auction process and in both delivery methods. The proposed guidance strategy is successful, in simulations, in autonomously assigning the members of the formation to new positions and in delivering the spacecraft to these new positions safely using both delivery methods. This guidance algorithm can serve as the basis for future autonomous guidance strategies for spacecraft formation missions.

Rendezvous radar for the orbital maneuvering vehicle

NASA Technical Reports Server (NTRS)

Locke, John W.; Olds, Keith A.; Quaid, Thomas

1991-01-01

The Rendezvous Radar Set (RRS) was designed at Motorola's Strategic Electronics Division in Chandler, Arizona, to be a key subsystem aboard NASA's Orbital Maneuvering Vehicle (OMV). The unmanned OMV, which was under development at TRW's Federal Systems Division in Redondo Beach, California, was designed to supplement the Shuttle's satellite delivery, retrieval, and maneuvering activities. The RRS was to be used to locate and then provide the OMV with vectoring information to the target satellite (or Shuttle or Space Station) to aid the OMV in making a minimum fuel consumption approach and rendezvous. The OMV development program was halted by NASA in 1990 just as parts were being ordered for the RRS engineering model. The paper presented describes the RRS design and then discusses new technologies, either under development or planned for development at Motorola, that can be applied to radar or alternative sensor solutions for the Automated Rendezvous and Capture problem.

Operationally optimal maneuver strategy for spacecraft injected into sub-geosynchronous transfer orbit

NASA Astrophysics Data System (ADS)

Kiran, B. S.; Singh, Satyendra; Negi, Kuldeep

The GSAT-12 spacecraft is providing Communication services from the INSAT/GSAT system in the Indian region. The spacecraft carries 12 extended C-band transponders. GSAT-12 was launched by ISRO’s PSLV from Sriharikota, into a sub-geosynchronous Transfer Orbit (sub-GTO) of 284 x 21000 km with inclination 18 deg. This Mission successfully accomplished combined optimization of launch vehicle and satellite capabilities to maximize operational life of the s/c. This paper describes mission analysis carried out for GSAT-12 comprising launch window, orbital events study and orbit raising maneuver strategies considering various Mission operational constraints. GSAT-12 is equipped with two earth sensors (ES), three gyroscopes and digital sun sensor. The launch window was generated considering mission requirement of minimum 45 minutes of ES data for calibration of gyros with Roll-sun-pointing orientation in T.O. Since the T.O. period was a rather short 6.1 hr, required pitch biases were worked out to meet the gyro-calibration requirement. A 440 N Liquid Apogee Motor (LAM) is used for orbit raising. The objective of the maneuver strategy is to achieve desired drift orbit satisfying mission constraints and minimizing propellant expenditure. In case of sub-GTO, the optimal strategy is to first perform an in-plane maneuver at perigee to raise the apogee to synchronous level and then perform combined maneuvers at the synchronous apogee to achieve desired drift orbit. The perigee burn opportunities were examined considering ground station visibility requirement for monitoring the burn. Two maneuver strategies were proposed: an optimal five-burn strategy with two perigee burns centered around perigee#5 and perigee#8 with partial ground station visibility and three apogee burns with dual station visibility, a near-optimal five-burn strategy with two off-perigee burns at perigee#5 and perigee#8 with single ground station visibility and three apogee burns with dual station visibility

Maneuver Analysis and Targeting Strategy for the Stardust Re-Entry Capsule

NASA Technical Reports Server (NTRS)

Helfrich, Cliff; Bhat, Ramachand S.; Kangas, Julie A.; Wilson, Roby S.; Wong, Mau C.; Potts, Christopher L.; Williams, Kenneth E.

2006-01-01

The Stardust Sample Return Capsule (SRC) returned to Earth on January 15, 2006 after seven years of collecting interstellar and comet particles over three heliocentric revolutions, as shown in Figure 1. The SRC was carried on board the Stardust spacecraft, as shown in Figure 2. Because the spacecraft was built with unbalanced thrusters, turns and attitude control maintenance resulted in undesirable delta-v being imparted to the trajectory. As a result, a carefully planned maneuver strategy was devised to accurately target the Stardust capsule to the Utah Test and Training Range (UTTR). This paper provides an overview of the Stardust spacecraft and mission and describes the maneuver strategy that was employed to achieve the stringent targeting requirements for landing in Utah. In addition, an overview of Stardust maneuver analysis tools and techniques will also be presented.

Polar versus Cartesian velocity models for maneuvering target tracking with IMM

NASA Astrophysics Data System (ADS)

Laneuville, Dann

This paper compares various model sets in different IMM filters for the maneuvering target tracking problem. The aim is to see whether we can improve the tracking performance of what is certainly the most widely used model set in the literature for the maneuvering target tracking problem: a Nearly Constant Velocity model and a Nearly Coordinated Turn model. Our new challenger set consists of a mixed Cartesian position and polar velocity state vector to describe the uniform motion segments and is augmented with the turn rate to obtain the second model for the maneuvering segments. This paper also gives a general procedure to discretize up to second order any non-linear continuous time model with linear diffusion. Comparative simulations on an air defence scenario with a 2D radar, show that this new approach improves significantly the tracking performance in this case.

Global Precipitation Measurement (GPM) Orbit Design and Autonomous Maneuvers

NASA Technical Reports Server (NTRS)

Folta, David; Mendelsohn, Chad

2003-01-01

The NASA Goddard Space Flight Center's Global Precipitation Measurement (GPM) mission will meet a challenge of measuring worldwide precipitation every three hours. The GPM spacecraft, part of a constellation, will be required to maintain a circular orbit in a high drag environment to accomplish this challenge. Analysis by the Flight Dynamics Analysis Branch has shown that the prime orbit altitude of 40% is necessary to prevent ground track repeating. Combined with goals to minimize maneuver impacts to science data collection and enabling reasonable long-term orbit predictions, the GPM project has decided to fly an autonomous maneuver system. This system is a derivative of the successful New Millennium Program technology flown onboard the Earth Observing-1 mission. This paper presents the driving science requirements and goals of the mission and shows how they will be met. Analysis of the orbit optimization and the AV requirements for several ballistic properties are presented. The architecture of the autonomous maneuvering system to meet the goals and requirements is presented along with simulations using a GPM prototype. Additionally, the use of the GPM autonomous system to mitigate possible collision avoidance and to aid other spacecraft systems during navigation outages is explored.

Effectiveness of cough etiquette maneuvers in disrupting the chain of transmission of infectious respiratory diseases

PubMed Central

2013-01-01

Background The effectiveness of recommended measures, such as “cover your mouth when coughing”, in disrupting the chain of transmission of infectious respiratory diseases (IRD) has been questioned. The objective of the current study was to determine the effectiveness of simple primary respiratory hygiene/cough etiquette maneuvers in blocking droplets expelled as aerosol during coughing. Method In this study, 31 healthy non-smokers performed cough etiquette maneuvers in an effort to cover their voluntarily elicited best effort coughs in an open bench format. A laser diffraction system was used to obtain accurate, non-invasive, quantitative, real time measurements of the size and number of droplets emitted during the assessed cough etiquette maneuvers. Results Recommended cough etiquette maneuvers did not block the release and dispersion of a variety of different diameter droplets to the surrounding environment. Droplets smaller than one-micron size dominate the total number of droplets leaked when practicing assessed maneuvers. Conclusions All the assessed cough etiquette maneuvers, performed as recommended, do not block droplets expelled as aerosol when coughing. This aerosol can penetrate profound levels of the respiratory system. Practicing these assessed primary respiratory hygiene/cough etiquette maneuvers would still permit direct, indirect, and/or airborne transmission and spread of IRD, such as influenza and Tuberculosis. All the assessed cough etiquette maneuvers, as recommended, do not fully interrupt the chain of transmission of IRD. This knowledge urges us all to critically review recommended CE and to search for new evidence-based procedures that effectively disrupt the transmission of respiratory pathogens. Interrupting the chain of transmission of IRD will optimize the protection of first responders, paramedics, nurses, and doctors working in triage sites, emergency rooms, intensive care units, and the general public against cough

Mapping sequence performed during the STS-121 R-Bar Pitch Maneuver

NASA Image and Video Library

2006-07-06

ISS013-E-47629 (6 July 2006) --- A close-up view of Space Shuttle Discovery's tail section is featured in this image photographed by an Expedition 13 crewmember on the International Space Station during STS-121 R-Pitch Maneuver survey on Flight Day 3. Visible are the shuttle's main engines, vertical stabilizer, orbital maneuvering system (OMS) pods, reaction control system (RCS) jets and a portion of payload bay door radiator and wings.

Manned maneuvering unit latching mechanism

NASA Technical Reports Server (NTRS)

Allton, C. S.

1980-01-01

The astronaut/Manned Maneuvering Unit interface, which presented a challenging set of requirements for a latching mechanism, is described. A spring loaded cam segment with variable ratio pulley release actuator was developed to meet the requirements. To preclude jamming of the mechanism, special precautions were taken such as spring loaded bearing points and careful selection of materials to resist cold welding. The mechanism successfully passed a number of tests which partially simulated orbital conditions.

Trajectory Control of Rendezvous with Maneuver Target Spacecraft

NASA Technical Reports Server (NTRS)

Zhou, Zhinqiang

2012-01-01

In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

Trial Maneuver Generation and Selection in the Paladin Tactical Decision Generation System

NASA Technical Reports Server (NTRS)

Chappell, Alan R.; McManus, John W.; Goodrich, Kenneth H.

1992-01-01

To date, increased levels of maneuverability and controllability in aircraft have been postulated as tactically advantageous, but little research has studied maneuvers or tactics that make use of these capabilities. In order to help fill this void, a real time tactical decision generation system for air combat engagements, Paladin, has been developed. Paladin models an air combat engagement as a series of discrete decisions. A detailed description of Paladin's decision making process is presented. This includes the sources of data used, methods of generating reasonable maneuvers for the Paladin aircraft, and selection criteria for choosing the "best" maneuver. Simulation results are presented that show Paladin to be relatively insensitive to errors introduced into the decision process by estimation of future positional and geometric data.

Trial maneuver generation and selection in the Paladin tactical decision generation system

NASA Technical Reports Server (NTRS)

Chappell, Alan R.; Mcmanus, John W.; Goodrich, Kenneth H.

1993-01-01

To date, increased levels of maneuverability and controllability in aircraft have been postulated as tactically advantageous, but little research has studied maneuvers or tactics that make use of these capabilities. In order to help fill this void, a real-time tactical decision generation system for air combat engagements, Paladin, has been developed. Paladin models an air combat engagement as a series of discrete decisions. A detailed description of Paladin's decision making process is presented. This includes the sources of data used, methods of generating reasonable maneuvers for the Paladin aircraft, and selection criteria for choosing the 'best' maneuver. Simulation results are presented that show Paladin to be relatively insensitive to errors introduced into the decision process by estimation of future positional and geometric data.

Five surgical maneuvers on nasal mucosa movement in cleft palate repair: A cadaver study.

PubMed

Nguyen, Dennis C; Patel, Kamlesh B; Parikh, Rajiv P; Skolnick, Gary B; Woo, Albert S

2016-06-01

This biomechanical study aims to characterize the nasal mucosa during palatoplasty, thereby describing the soft tissue attachments at different zones and quantifying movement following their release. Palatal nasal mucosa was exposed and divided in the midline in 10 adult cadaver heads. Five consecutive maneuvers were performed: (1) elevation of nasal mucosa off the maxilla, (2) dissection of nasal mucosa from soft palate musculature, (3) separation of nasal mucosa from palatine aponeurosis, (4) release of mucosa at the pterygopalatine junction, and (5) mobilization of vomer flaps. The mucosal movements across the midline at the midpalate (MP) and posterior nasal spine (PNS) following each maneuver were measured. At the MP, maneuvers 1-4 cumulatively provided 3.8 mm (36.9%), 4.9 mm (47.6%), 6.1 mm (59.2%), and 10.3 mm, respectively. Vomer flap (10.5 mm) elevation led to mobility equivalent to that of maneuvers 1-4 (p = 0.72). At the PNS, cumulative measurements after maneuvers 1-4 were 1.3 mm (10%), 2.4 mm (18.6%), 5.7 mm (44.2%), and 12.9 mm. Here, vomer flaps (6.5 mm) provided less movement (p < 0.001). Maneuver 4 yielded the greatest amount of movement of the lateral nasal mucosa at both MP (4.2 mm, 40.8%) and PNS (7.2 mm, 55.8%). At the MP, complete release of the lateral nasal mucosa achieves as much movement as the vomer flap. At the hard-soft palate junction, the maneuvers progressively add to the movement of the lateral nasal mucosa. The most powerful step is release of attachments along the posterior aspect of the medial pterygoid. Published by Elsevier Ltd.

77 FR 70384 - Special Conditions: Embraer S.A., Model EMB-550 Airplane; Design Roll Maneuver for Electronic...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-26

... design roll maneuver for electronic flight controls, specifically an electronic flight control system... load condition at design maneuvering speed (V A ), in which the cockpit roll control is returned to...-550 airplanes. 1. Design Roll Maneuver for Electronic Flight Controls. In lieu of compliance to 14 CFR...

Three-Axis Time-Optimal Attitude Maneuvers of a Rigid-Body

NASA Astrophysics Data System (ADS)

Wang, Xijing; Li, Jisheng

With the development trends for modern satellites towards macro-scale and micro-scale, new demands are requested for its attitude adjustment. Precise pointing control and rapid maneuvering capabilities have long been part of many space missions. While the development of computer technology enables new optimal algorithms being used continuously, a powerful tool for solving problem is provided. Many papers about attitude adjustment have been published, the configurations of the spacecraft are considered rigid body with flexible parts or gyrostate-type systems. The object function always include minimum time or minimum fuel. During earlier satellite missions, the attitude acquisition was achieved by using the momentum ex change devices, performed by a sequential single-axis slewing strategy. Recently, the simultaneous three-axis minimum-time maneuver(reorientation) problems have been studied by many researchers. It is important to research the minimum-time maneuver of a rigid spacecraft within onboard power limits, because of potential space application such as surveying multiple targets in space and academic value. The minimum-time maneuver of a rigid spacecraft is a basic problem because the solutions for maneuvering flexible spacecraft are based on the solution to the rigid body slew problem. A new method for the open-loop solution for a rigid spacecraft maneuver is presented. Having neglected all perturbation torque, the necessary conditions of spacecraft from one state to another state can be determined. There is difference between single-axis with multi-axis. For single- axis analytical solution is possible and the switching line passing through the state-space origin belongs to parabolic. For multi-axis, it is impossible to get analytical solution due to the dynamic coupling between the axes and must be solved numerically. Proved by modern research, Euler axis rotations are quasi-time-optimal in general. On the basis of minimum value principles, a research for

A unified flight control methodology for a compound rotorcraft in fundamental and aerobatic maneuvering flight

NASA Astrophysics Data System (ADS)

Thorsen, Adam

This study investigates a novel approach to flight control for a compound rotorcraft in a variety of maneuvers ranging from fundamental to aerobatic in nature. Fundamental maneuvers are a class of maneuvers with design significance that are useful for testing and tuning flight control systems along with uncovering control law deficiencies. Aerobatic maneuvers are a class of aggressive and complex maneuvers with more operational significance. The process culminating in a unified approach to flight control includes various control allocation studies for redundant controls in trim and maneuvering flight, an efficient methodology to simulate non-piloted maneuvers with varying degrees of complexity, and the setup of an unconventional control inceptor configuration along with the use of a flight simulator to gather pilot feedback in order to improve the unified control architecture. A flight path generation algorithm was developed to calculate control inceptor commands required for a rotorcraft in aerobatic maneuvers. This generalized algorithm was tailored to generate flight paths through optimization methods in order to satisfy target terminal position coordinates or to minimize the total time of a particular maneuver. Six aerobatic maneuvers were developed drawing inspiration from air combat maneuvers of fighter jet aircraft: Pitch-Back Turn (PBT), Combat Ascent Turn (CAT), Combat Descent Turn (CDT), Weaving Pull-up (WPU), Combat Break Turn (CBT), and Zoom and Boom (ZAB). These aerobatic maneuvers were simulated at moderate to high advance ratios while fundamental maneuvers of the compound including level accelerations/decelerations, climbs, descents, and turns were investigated across the entire flight envelope to evaluate controller performance. The unified control system was developed to allow controls to seamlessly transition between manual and automatic allocations while ensuring that the axis of control for a particular inceptor remained constant with flight

Concurrent image-based visual servoing with adaptive zooming for non-cooperative rendezvous maneuvers

NASA Astrophysics Data System (ADS)

Pomares, Jorge; Felicetti, Leonard; Pérez, Javier; Emami, M. Reza

2018-02-01

An image-based servo controller for the guidance of a spacecraft during non-cooperative rendezvous is presented in this paper. The controller directly utilizes the visual features from image frames of a target spacecraft for computing both attitude and orbital maneuvers concurrently. The utilization of adaptive optics, such as zooming cameras, is also addressed through developing an invariant-image servo controller. The controller allows for performing rendezvous maneuvers independently from the adjustments of the camera focal length, improving the performance and versatility of maneuvers. The stability of the proposed control scheme is proven analytically in the invariant space, and its viability is explored through numerical simulations.

High alpha feedback control for agile half-loop maneuvers of the F-18 airplane

NASA Technical Reports Server (NTRS)

Stalford, Harold

1988-01-01

A nonlinear feedback control law for the F/A-18 airplane that provides time-optimal or agile maneuvering of the half-loop maneuver at high angles of attack is given. The feedback control law was developed using the mathematical approach of singular perturbations, in which the control devices considered were conventional aerodynamic control surfaces and thrusting. The derived nonlinear control law was used to simulate F/A-18 half-loop maneuvers. The simulated results at Mach 0.6 and 0.9 compared well with pilot simulations conducted at NASA.

Propulsion System and Orbit Maneuver Integration in CubeSats: Trajectory Control Strategies Using Micro Ion Propulsion

NASA Technical Reports Server (NTRS)

Hudson, Jennifer; Martinez, Andres; Petro, Andrew

2015-01-01

The Propulsion System and Orbit Maneuver Integration in CubeSats project aims to solve the challenges of integrating a micro electric propulsion system on a CubeSat in order to perform orbital maneuvers and control attitude. This represents a fundamentally new capability for CubeSats, which typically do not contain propulsion systems and cannot maneuver far beyond their initial orbits.

Mars Science Laboratory Propulsive Maneuver Design and Execution

NASA Technical Reports Server (NTRS)

Wong, Mau C.; Kangas, Julie A.; Ballard, Christopher G.; Gustafson, Eric D.; Martin-Mur, Tomas J.

2012-01-01

The NASA Mars Science Laboratory (MSL) rover, Curiosity, was launched on November 26, 2011 and successfully landed at the Gale Crater on Mars. For the 8-month interplanetary trajectory from Earth to Mars, five nominal and two contingency trajectory correction maneuvers (TCM) were planned. The goal of these TCMs was to accurately deliver the spacecraft to the desired atmospheric entry aimpoint in Martian atmosphere so as to ensure a high probability of successful landing on the Mars surface. The primary mission requirements on maneuver performance were the total mission propellant usage and the entry flight path angle (EFPA) delivery accuracy. They were comfortably met in this mission. In this paper we will describe the spacecraft propulsion system, TCM constraints and requirements, TCM design processes, and their implementation and verification.

Automatic procedures generator for orbital rendezvous maneuver

NASA Technical Reports Server (NTRS)

Kohn, W.; Van Valkenburg, J. A.; Dunn, C. K.

1985-01-01

This paper describes the development of an expert system for defining and dynamically updating procedures for an orbital rendezvous maneuver. The product of the expert system is a procedure represented by a Moore automaton. The construction is recursive and driven by a simulation of the rendezvousing bodies.

Maneuver Estimation Model for Geostationary Orbit Determination

DTIC Science & Technology

2006-06-01

create a more robust model which would reduce the amount of data needed to make accurate maneuver estimations. The Clohessy - Wiltshire equations were...Applications to Geostationary Satellites...........................................7 2.3.2 Clohessy - Wiltshire Equations...15 3.1.1 Application of Clohessy - Wiltshire Equations ................................15 3.1.2

14 CFR 25.331 - Symmetric maneuvering conditions.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Where sudden displacement of a control is specified, the assumed rate of control surface displacement... torque or maximum rate obtainable by a power control system.) (1) Maximum pitch control displacement at V..., whichever occurs first, need not be considered. (2) Specified control displacement. A checked maneuver...

The Pringle maneuver reduces the infusion rate of rocuronium required to maintain surgical muscle relaxation during hepatectomy.

PubMed

Kajiura, Akira; Nagata, Osamu; Sanui, Masamitsu

2018-04-27

We investigated the continuous infusion rates of rocuronium necessary to obtain the surgical muscle relaxation before, during, and after the Pringle maneuver on patients who underwent hepatectomy. Fifteen patients were induced by total intravenous anesthesia with propofol. After obtaining the calibration of acceleromyography, the patient was intubated with rocuronium 0.6 mg/kg. Fifteen minutes after initial rocuronium injection, the continuous infusion was started at 7.5 µg/kg/min. The infusion rate was adjusted every 15 min so that the first twitch height (% T1) might become from 3 to 10% of control. The infusion rates at the time when the state of surgical muscle relaxation was achieved for more than 15 min were recorded before, during and after the Pringle maneuver. The 25% recovery time was measured after discontinuing the continuous infusion. The infusion rate of rocuronium before, during, and after the Pringle maneuver was 7.2 ± 1.8, 4.2 ± 1.4, and 4.7 ± 1.5 µg/kg/min (mean ± SD), respectively. The rocuronium infusion rate during the Pringle maneuver was decreased about 40% compared to that before this maneuver, and that after completion of the Pringle maneuver was not recovered to that before the Pringle maneuver. The 25% recovery time was 20 ± 7 min. In case of continuous administration of rocuronium during surgery performing the Pringle maneuver, it was considered necessary to regulate the administration of rocuronium using muscle relaxant monitoring in order to deal with the decrease in muscle relaxant requirement by the Pringle maneuver.

Zero-Propellant Maneuver[TM] Flight Results for 180 deg ISS Rotation

NASA Technical Reports Server (NTRS)

Bedrossian, Nazareth; Bhatt, Sagar; Lammers, Mike; Nguyen, Louis

2007-01-01

This paper presents results for the Zero Propellant Maneuver (ZPM) TradeMark attitude control concept flight demonstration. On March 3, 2007, a ZPM was used to reorient the International Space Station 180 degrees without using any propellant. The identical reorientation performed with thrusters would have burned 110lbs of propellant. The ZPM was a pre-planned trajectory used to command the CMG attitude hold controller to perform the maneuver between specified initial and final states while maintaining the CMGs within their operational limits. The trajectory was obtained from a PseudoSpectral solution to a new optimal attitude control problem. The flight test established the breakthrough capability to simultaneously perform a large angle attitude maneuver and momentum desaturation without the need to use thrusters. The flight implementation did not require any modifications to flight software. This approach is applicable to any spacecraft that are controlled by momentum storage devices.

Ventral medial prefrontal cortex (vmPFC) as a target of the dorsolateral prefrontal modulation by transcranial direct current stimulation (tDCS) in drug addiction.

PubMed

Nakamura-Palacios, Ester Miyuki; Lopes, Isabela Bittencourt Coutinho; Souza, Rodolpho Albuquerque; Klauss, Jaisa; Batista, Edson Kruger; Conti, Catarine Lima; Moscon, Janine Andrade; de Souza, Rodrigo Stênio Moll

2016-10-01

Here, we report some electrophysiologic and imaging effects of the transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (dlPFC) in drug addiction, notably in alcohol and crack-cocaine dependence. The low resolution electromagnetic tomography (LORETA) analysis obtained through event-related potentials (ERPs) under drug-related cues, more specifically in its P3 segment (300-500 ms) in both, alcoholics and crack-cocaine users, showed that the ventral medial prefrontal cortex (vmPFC) was the brain area with the largest change towards increasing activation under drug-related cues in those subjects that kept abstinence during and after the treatment with bilateral tDCS (2 mA, 35 cm(2), cathodal left and anodal right) over dlPFC, applied repetitively (five daily sessions). In an additional study in crack-cocaine, which showed craving decreases after repetitive bilateral tDCS, we examined data originating from diffusion tensor imaging (DTI), and we found increased DTI parameters in the left connection between vmPFC and nucleus accumbens (NAcc), such as the number of voxels, fractional anisotropy (FA) and apparent diffusion coefficient (ADC), in tDCS-treated crack-cocaine users when compared to the sham-tDCS group. This increasing of DTI parameters was significantly correlated with craving decreasing after the repetitive tDCS. The vmPFC relates to the control of drug seeking, possibly by extinguishing this behavior. In our studies, the bilateral dlPFC tDCS reduced relapses and craving to the drug use, and increased the vmPFC activation under drug cues, which may be of a great importance in the control of drug use in drug addiction.

Maneuver from the Air Domain

DTIC Science & Technology

2016-05-26

York, NY: Ballantine Books, 1991), 27-58. Examples include Sun Tzu , Genghis Kahn, Napoleon, the post WWI Soviet military, and the WWII-era German...it to a position of advantage.26 In simple terms, maneuver warfare is summed up by the idea of a force dichotomy, explained by Sun Tzu as separate...ordinary” and “extraordinary” forces within the army. Sun Tzu said that in battle, the ordinary force should seek to pin down the enemy’s front line

The Maneuver-Sustainment Dynamic Model

DTIC Science & Technology

1990-04-30

free of obstructions, offered hitherto unforeseen possibilities,(18) He quickly tu,’ned the possibilities into reality. 15 After landing in Tunisia in...captured by Allied forces on the coast of 19 Tunisia . Application of the Maneuver-Sustainment Model Risk Rommel made the distinction between boldness and a...victory in North Africa. Shortly after his arrival in Tunisia in April 1941, Rommel stated: I had made up my mind to stand out from the start for the

Precision Closed-Loop Orbital Maneuvering System Design and Performance for the Magnetospheric Multi-Scale Mission (MMS) Formation

NASA Technical Reports Server (NTRS)

Chai, Dean; Queen, Steve; Placanica, Sam

2015-01-01

NASA's Magnetospheric Multi-Scale (MMS) mission successfully launched on March 13, 2015 (UTC) consists of four identically instrumented spin-stabilized observatories that function as a constellation to study magnetic reconnection in space. The need to maintain sufficiently accurate spatial and temporal formation resolution of the observatories must be balanced against the logistical constraints of executing overly-frequent maneuvers on a small fleet of spacecraft. These two considerations make for an extremely challenging maneuver design problem. This paper focuses on the design elements of a 6-DOF spacecraft attitude control and maneuvering system capable of delivering the high-precision adjustments required by the constellation designers---specifically, the design, implementation, and on-orbit performance of the closed-loop formation-class maneuvers that include initialization, maintenance, and re-sizing. The maneuvering control system flown on MMS utilizes a micro-gravity resolution accelerometer sampled at a high rate in order to achieve closed-loop velocity tracking of an inertial target with arc-minute directional and millimeter-per-second magnitude accuracy. This paper summarizes the techniques used for correcting bias drift, sensor-head offsets, and centripetal aliasing in the acceleration measurements. It also discusses the on-board pre-maneuver calibration and compensation algorithms as well as the implementation of the post-maneuver attitude adjustments.

Tracking of Maneuvering Complex Extended Object with Coupled Motion Kinematics and Extension Dynamics Using Range Extent Measurements

PubMed Central

Sun, Lifan; Ji, Baofeng; Lan, Jian; He, Zishu; Pu, Jiexin

2017-01-01

The key to successful maneuvering complex extended object tracking (MCEOT) using range extent measurements provided by high resolution sensors lies in accurate and effective modeling of both the extension dynamics and the centroid kinematics. During object maneuvers, the extension dynamics of an object with a complex shape is highly coupled with the centroid kinematics. However, this difficult but important problem is rarely considered and solved explicitly. In view of this, this paper proposes a general approach to modeling a maneuvering complex extended object based on Minkowski sum, so that the coupled turn maneuvers in both the centroid states and extensions can be described accurately. The new model has a concise and unified form, in which the complex extension dynamics can be simply and jointly characterized by multiple simple sub-objects’ extension dynamics based on Minkowski sum. The proposed maneuvering model fits range extent measurements very well due to its favorable properties. Based on this model, an MCEOT algorithm dealing with motion and extension maneuvers is also derived. Two different cases of the turn maneuvers with known/unknown turn rates are specifically considered. The proposed algorithm which jointly estimates the kinematic state and the object extension can also be easily implemented. Simulation results demonstrate the effectiveness of the proposed modeling and tracking approaches. PMID:28937629

Broken-Plane Maneuver Applications for Earth to Mars Trajectories

NASA Technical Reports Server (NTRS)

Abilleira, Fernando

2007-01-01

Optimization techniques are critical when investigating Earth to Mars trajectories since they have the potential of reducing the total (delta)V of a mission. A deep space maneuver (DSM) executed during the cruise may improve a trajectory by reducing the total mission V. Nonetheless, DSMs not only may improve trajectory performance (from an energetic point of view) but also open up new families of trajectories that would satisfy very specific mission requirements not achievable with ballistic trajectories. In the following pages, various specific examples showing the potential advantages of the usage of broken plane maneuvers will be introduced. These examples correspond to possible scenarios for Earth to Mars trajectories during the next decade (2010-2020).

Active Control of Solar Array Dynamics During Spacecraft Maneuvers

NASA Technical Reports Server (NTRS)

Ross, Brant A.; Woo, Nelson; Kraft, Thomas G.; Blandino, Joseph R.

2016-01-01

Recent NASA mission plans require spacecraft to undergo potentially significant maneuvers (or dynamic loading events) with large solar arrays deployed. Therefore there is an increased need to understand and possibly control the nonlinear dynamics in the spacecraft system during such maneuvers. The development of a nonlinear controller is described. The utility of using a nonlinear controller to reduce forces and motion in a solar array wing during a loading event is demonstrated. The result is dramatic reductions in system forces and motion during a 10 second loading event. A motion curve derived from the simulation with the closed loop controller is used to obtain similar benefits with a simpler motion control approach.

14 CFR 25.351 - Yaw maneuver conditions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Yaw maneuver conditions. 25.351 Section 25.351 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... airplane inertia forces. In computing the tail loads the yawing velocity may be assumed to be zero. (a...

14 CFR 25.351 - Yaw maneuver conditions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Yaw maneuver conditions. 25.351 Section 25.351 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... airplane inertia forces. In computing the tail loads the yawing velocity may be assumed to be zero. (a...

Effect of width and boundary conditions on meeting maneuvers on two-way separated cycle tracks.

PubMed

Garcia, Alfredo; Gomez, Fernando Agustin; Llorca, Carlos; Angel-Domenech, Antonio

2015-05-01

Cycle track design guidelines are rarely based on scientific studies. In the case of off-road two-way cycle tracks, a minimum width must facilitate both passing and meeting maneuvers, being meeting maneuvers the most frequent. This study developed a methodology to observe meeting maneuvers using an instrumented bicycle, equipped with video cameras, a GPS tracker, laser rangefinders and speed sensors. This bicycle collected data on six two-way cycle tracks ranging 1.3-2.15m width delimitated by different boundary conditions. The meeting maneuvers between the instrumented bicycle and every oncoming bicycle were characterized by the meeting clearance between the two bicycles, the speed of opposing bicycle and the reaction of the opposing rider: change in trajectory, stop pedaling or braking. The results showed that meeting clearance increased with the cycle track width and decreased if the cycle track had lateral obstacles, especially if they were higher than the bicycle handlebar. The speed of opposing bicycle shown the same tendency, although were more disperse. Opposing cyclists performed more reaction maneuvers on narrower cycle tracks and on cycle tracks with lateral obstacles to the handlebar height. Conclusions suggested avoiding cycle tracks narrower than 1.6m, as they present lower meeting clearances, lower bicycle speeds and frequent reaction maneuvers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Space Objects Maneuvering Detection and Prediction via Inverse Reinforcement Learning

NASA Astrophysics Data System (ADS)

Linares, R.; Furfaro, R.

This paper determines the behavior of Space Objects (SOs) using inverse Reinforcement Learning (RL) to estimate the reward function that each SO is using for control. The approach discussed in this work can be used to analyze maneuvering of SOs from observational data. The inverse RL problem is solved using the Feature Matching approach. This approach determines the optimal reward function that a SO is using while maneuvering by assuming that the observed trajectories are optimal with respect to the SO's own reward function. This paper uses estimated orbital elements data to determine the behavior of SOs in a data-driven fashion.

Global Precipitation Measurement (GPM) Orbit Design and Autonomous Maneuvers

NASA Technical Reports Server (NTRS)

Folta, David; Mendelsohn, Chad; Mailhe, Laurie

2003-01-01

The NASA Goddard Space Flight Center's Global Precipitation Measurement (GPM) mission must meet the challenge of measuring worldwide precipitation every three hours. The GPM core spacecraft, part of a constellation, will be required to maintain a circular orbit in a high drag environment at a near-critical inclination. Analysis shows that a mean orbit altitude of 407 km is necessary to prevent ground track repeating. Combined with goals to minimize maneuver operation impacts to science data collection and to enable reasonable long-term orbit predictions, the GPM project has decided to fly the GSFC autonomous maneuver system, AutoCon(TM). This system is a follow-up version of the highly successful New Millennium Program technology flown onboard the Earth Observing-1 formation flying mission. This paper presents the driving science requirements and goals of the GPM mission and shows how they will be met. Selection of the mean semi-major axis, eccentricity, and the AV budget for several ballistic properties are presented. The architecture of the autonomous maneuvering system to meet the goals and requirements is presented along with simulations using GPM parameters. Additionally, the use of the GPM autonomous system to mitigate possible collision avoidance and to aid other spacecraft systems during navigation outages is explored.

Exact nonlinear command generation and tracking for robot manipulators and spacecraft slewing maneuvers

NASA Technical Reports Server (NTRS)

Dywer, T. A. W., III; Lee, G. K. F.

1984-01-01

In connection with the current interest in agile spacecraft maneuvers, it has become necessary to consider the nonlinear coupling effects of multiaxial rotation in the treatment of command generation and tracking problems. Multiaxial maneuvers will be required in military missions involving a fast acquisition of moving targets in space. In addition, such maneuvers are also needed for the efficient operation of robot manipulators. Attention is given to details regarding the direct nonlinear command generation and tracking, an approach which has been successfully applied to the design of control systems for V/STOL aircraft, linearizing transformations for spacecraft controlled with external thrusters, the case of flexible spacecraft dynamics, examples from robot dynamics, and problems of implementation and testing.

Glacial Isostatic Adjustment with ICE-6G{_}C (VM5a) and Laterally Heterogeneous Mantle Viscosity

NASA Astrophysics Data System (ADS)

Li, Tanghua; Wu, Patrick; Steffen, Holger

2017-04-01

Recently, Peltier et al. (2015) introduced the ICE-6GC (VM5a) ice-earth model pair, which has successfully explained many observations of Glacial Isostatic Adjustment (GIA) simultaneously. However, their earth model used (VM5a) to infer the ice history (ICE-6G_C) is laterally homogeneous with viscosity profile varying in the radial direction only. Since surface geology and seismic tomography clearly indicates that the Earth's material properties also vary in the lateral direction, laterally heterogeneity must be included in GIA models. This can be achieved by using the Coupled-Laplace-Finite-Element method (Wu 2004) to model GIA in a spherical, self-gravitating, compressible viscoelastic Earth with linear rheology and lateral heterogeneity. In fact, Wu et al (2013) have used such model with GIA observations (e.g. global relative sea level data, GRACE data with recent hydrology contributions removed and GPS crustal uplift rates) to study the thermal contribution to lateral heterogeneity in the mantle. Their lateral viscosity perturbations are inferred from the seismic shear wave tomography model S20A (Ekstrom & Dziewonski 1998) by applying a scaling law, which includes both the effect of anharmonicity and anelasticity. The thermal contribution to seismic tomography, which is represented by the beta factor in the scaling relationship, is searched in the upper and lower mantle, for the best combination that gives the best fit between GIA predictions and observations. However, their study is based on ICE-4G only, and the new ice-earth model pair may give other best beta value combinations in the upper and lower mantle. Here, we follow the work of Wu et al (2013) but use the new ICE-6GC ice model instead. The higher resolution seismic tomography model by Bunge & Grand (2000) substitutes S20A. Earth model VM5a is used as the reference background viscosity model. The full viscosity model is obtained by superposing the background model with the lateral viscosity

Effect of Breathing Technique of Blowing on the Extent of Damage to the Perineum at the Moment of Delivery: A Randomized Clinical Trial

PubMed Central

Ahmadi, Zohre; Torkzahrani, Shahnaz; Roosta, Firouze; Shakeri, Nezhat; Mhmoodi, Zohre

2017-01-01

Introduction: One of the important tasks in managing labor is the protection of perineum. An important variable affecting this outcome is maternal pushing during the second stage of labor. This study was done to investigate the effect of breathing technique on perineal damage extention in laboring Iranian women. Materials and Methods: This randomized clinical trial was performed on 166 nulliparous pregnant women who had reached full-term pregnancy, had low risk pregnancy, and were candidates for vaginal delivery in two following groups: using breathing techniques (case group) and valsalva maneuver (control group). In the control group, pushing was done with holding the breath. In the case group, the women were asked to take 2 deep abdominal breaths at the onset of pain, then take another deep breath, and push 4–5 seconds with the open mouth while controlling exhalation. From the crowning stage onward, the women were directed to control their pushing, and do the blowing technique. Results: According to the results, intact perineum was more observed in the case group (P = 0.002). Posterior tears (Grade 1, 2, and 3) was considerably higher in the control group (P = 0.003). Anterior tears (labias) and episiotomy were not significantly different in the two groups. Conclusions: It was concluded that breathing technique of blowing can be a good alternative to Valsalva maneuver in order to reduce perineal damage in laboring women. PMID:28382061

Pelvic Floor Dynamics During High-Impact Athletic Activities: A Computational Modeling Study

PubMed Central

Dias, Nicholas; Peng, Yun; Khavari, Rose; Nakib, Nissrine A.; Sweet, Robert M.; Timm, Gerald W.; Erdman, Arthur G.; Boone, Timothy B.

2017-01-01

Background Stress urinary incontinence is a significant problem in young female athletes, but the pathophysiology remains unclear because of the limited knowledge of the pelvic floor support function and limited capability of currently available assessment tools. The aim of our study is to develop an advanced computer modeling tool to better understand the dynamics of the internal pelvic floor during highly transient athletic activities. Methods Apelvic model was developed based on high-resolution MRI scans of a healthy nulliparous young female. A jump-landing process was simulated using realistic boundary conditions captured from jumping experiments. Hypothesized alterations of the function of pelvic floor muscles were simulated by weakening or strengthening the levator ani muscle stiffness at different levels. Intra-abdominal pressures and corresponding deformations of pelvic floor structures were monitored at different levels of weakness or enhancement. Findings Results show that pelvic floor deformations generated during a jump-landing process differed greatly from those seen in a Valsalva maneuver which is commonly used for diagnosis in clinic. The urethral mobility was only slightly influenced by the alterations of the levator ani muscle stiffness. Implications for risk factors and treatment strategies were also discussed. Interpretation Results suggest that clinical diagnosis should make allowances for observed differences in pelvic floor deformations between a Valsalva maneuver and a jump-landing process to ensure accuracy. Urethral hypermobility may be a less contributing factor than the intrinsic sphincteric closure system to the incontinence of young female athletes. PMID:27886590

Patent Foramen Ovale in Patients with Cerebral Infarction: A Transesophageal Echocradigraphy Study

NASA Technical Reports Server (NTRS)

Petty, George W.; Khandheria, Bijoy K.; Chu, Chu-Pin; Sicks, JoRean D.; Whisnant, Jack P.

1997-01-01

Patent foramen ovale was detected in 37 patients (32%). Mean age was similar in those with (60 years) and those without (64 years) PFO. Patent foramen ovale was more frequent among men (39%) than women (20%, P=.03). Patients with PFO had a lower frequency of atrial fibrillation, diabetes me!litus, hypertension, and peripheral vascular disease compared with those without PFO. There was no difference in frequency of the following characteristics in patients with PFO compared with those without PFO: pulmonary embolus, chronic obstructive pulmonary disease, pulmonary hypertension, peripheral embolism, prior cerebral infarction, nosocomial cerebral infarction, Valsalva maneuver at the time of cerebral infarction, recent surgery, or hemorrhagic transformation of cerebral infarction. Patent foramen ovale was found in 22 (40%) of 55 patients with infarcts of uncertain cause and in 15 (25%) of 61 with infarcts of known cause (cardioembolic, 21%; large vessel atherostenosis, 25%; lacune, 40%) (P=.08). When the analysis was restricted to patients who underwent Valsalva maneuver, PFO with right to left or bidirectional shunt was found in 19 (50%) of 38 patients with infarcts of uncertain cause and in 6 (20%) of 30 with infarcts of known cause (P=.Ol). Conclusion: Although PFO was over-represented in patients with infarcts of uncertain cause in our and other studies, it has a high frequency among patients with cerebral infarction of all types. The relation between PFO and stroke requires further study.

14 CFR 23.1567 - Flight maneuver placard.

Code of Federal Regulations, 2010 CFR

2010-01-01

... requirements for acrobatic category airplanes, an additional placard in clear view of the pilot stating: “Spins... pilot— (1) Listing the control actions for recovery from spinning maneuvers; and (2) Stating that recovery must be initiated when spiral characteristics appear, or after not more than six turns or not more...

14 CFR 23.1567 - Flight maneuver placard.

Code of Federal Regulations, 2013 CFR

2013-01-01

... requirements for acrobatic category airplanes, an additional placard in clear view of the pilot stating: “Spins... pilot— (1) Listing the control actions for recovery from spinning maneuvers; and (2) Stating that recovery must be initiated when spiral characteristics appear, or after not more than six turns or not more...

[Effects of recruitment maneuver in prone position on hemodynamics in patients with severe pulmonary infection].

PubMed

Fan, Yuan-hua; Liu, Yuan-fei; Zhu, Hua-yong; Zhang, Min

2012-02-01

To evaluate effects of recruitment maneuver in prone position on hemodynamics in patients with severe pulmonary infection, based on the protective pulmonary ventilation strategy. Ninety-seven cases with severe pulmonary infection admitted to intensive care unit (ICU) of Ganzhou City People's Hospital undergoing mechanical ventilation were involved. Volume controlled ventilation mode with small tidal volume (8 ml/kg) and positive end-expiratory pressure (PEEP) of 6 cm H(2)O [1 cm H(2)O = 0.098 kPa] was conducted. Each patient underwent recruitment maneuver in supine position and then in prone position [PEEP 20 cm H(2)O+pressure control (PC) 20 cm H(2)O]. Heart rate (HR), mean arterial pressure (MAP), pulse oxygen saturation [SpO(2)] and blood gas analysis data were recorded before and after recruitment maneuver in either position. A double-lumen venous catheter was inserted into internal jugular vein or subclavian vein, and a pulse index contour cardiac output (PiCCO) catheter was introduced into femoral artery. Cardiac index (CI), stroke volume index (SVI), systemic vascular resistance index (SVRI), intra-thoracic blood volume index (ITBVI), extra vascular lung water index (EVLWI), global end-diastolic volume index (GEDVI), global ejection fraction (GEF), stroke volume variation (SVV) and central vein pressure (CVP) were monitored. (1) Compared with data before recruitment maneuver, there were no significant differences in HR and MAP after supine position and prone position recruitment maneuver, but significant differences in SpO(2) were found between before and after recruitment maneuver when patients' position was changed (supine position: 0.954 ± 0.032 vs. 0.917 ± 0.025, P < 0.05; prone position: 0.982 ± 0.028 vs. 0.936 ± 0.039, P < 0.05). SpO(2) was higher in prone position recruitment maneuver (P < 0.05). (2) Compared with data before recruitment maneuver, CI [L×min(-1)×m(-2)], SVI (ml/m(2)), GEDVI (ml/m(2)) and GEF were decreased significantly during

A lightweight pumped hydrazine orbit maneuvering space vehicle

NASA Astrophysics Data System (ADS)

Whitehead, J. C.

1992-01-01

An orbital maneuvering vehicle has a pair of opposed cylindrical piston tanks for hydrazine, and four transverse liquid rocket engines along a longitudinal plane. A new kind of pumped rocket propulsion provides maneuvering thrust on demand, and free-piston pumps which can rapidly start and stop are radially oriented between thrusters. A major advantage of this configuration is that the tanks can be close together, which maximizes the vehicle's longitudinal bending stiffness while minimizing the mass of the central bridging structure. The impulses from pump exhaust and piston reciprocation are directed through the system mass center, so they apply no disturbance torques. All high-temperature components are located on the outside of the central structure, where they are free to expand and radiate heat without detrimental effects. Virtually all lightweight components have been fabricated and tested, and photographs of hardware subassemblies are presented.

Quest airlock maneuvered into position

NASA Image and Video Library

2001-07-15

STS104-E-5068 (15 July 2001) --- Backdropped against a blue and white Earth, some 237 miles below, the Quest airlock is in the process of being installed onto the starboard side of Unity Node 1 of the International Space Station (ISS). Astronaut Susan J. Helms, Expedition Two flight engineer, used controls onboard the station to maneuver the Airlock into place with the Canadarm2 or Space Station Remote Manipulator System (SSRMS). This image was recorded with a digital still camera.

76 FR 36870 - Special Conditions: Gulfstream Model GVI Airplane; Design Roll Maneuver Requirement for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-23

... airplane will have a novel or unusual design feature associated with an electronic flight control system... load condition at design maneuvering speed (V A ), in which the cockpit roll control is returned to... positive maneuvering factor used in design. In determining the resulting control surface deflections, the...

Implementation of an Autonomous Multi-Maneuver Targeting Sequence for Lunar Trans-Earth Injection

NASA Technical Reports Server (NTRS)

Whitley, Ryan J.; Williams, Jacob

2010-01-01

Using a fully analytic initial guess estimate as a first iterate, a targeting procedure that constructs a flyable burn maneuver sequence to transfer a spacecraft from any closed Moon orbit to a desired Earth entry state is developed and implemented. The algorithm is built to support the need for an anytime abort capability for Orion. Based on project requirements, the Orion spacecraft must be able to autonomously calculate the translational maneuver targets for an entire Lunar mission. Translational maneuver target sequences for the Orion spacecraft include Lunar Orbit Insertion (LOI), Trans-Earth Injection (TEI), and Trajectory Correction Maneuvers (TCMs). This onboard capability is generally assumed to be supplemental to redundant ground computation in nominal mission operations and considered as a viable alternative primarily in loss of communications contingencies. Of these maneuvers, the ability to accurately and consistently establish a flyable 3-burn TEI target sequence is especially critical. The TEI is the sole means by which the crew can successfully return from the Moon to a narrowly banded Earth Entry Interface (EI) state. This is made even more critical by the desire for global access on the lunar surface. Currently, the designed propellant load is based on fully optimized TEI solutions for the worst case geometries associated with the accepted range of epochs and landing sites. This presents two challenges for an autonomous algorithm: in addition to being feasible, the targets must include burn sequences that do not exceed the anticipated propellant load.

Astronaut Alan Bean flies the Astronaut Maneuvering Equipment in the OWS

NASA Technical Reports Server (NTRS)

1973-01-01

Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment, as seen in this photographic reproduction taken from a television transmission made by a color television camera in the Orbital Workshop (OWS) of the Skylab space station in Earth orbit. Bean is strapped into the back-mounted, hand-controlled Automatically stabilized Maneuvering Unit (ASMU). The M509 exercise was in the forward dome area of the OWS. THe dome area is about 22 feet in diameter and 19 feet form top to bottom.

Effect of Anticipation on Lower Extremity Biomechanics During Side- and Cross-Cutting Maneuvers in Young Soccer Players.

PubMed

Kim, Jin Hyun; Lee, Ki-Kwang; Kong, Se Jin; An, Keun Ok; Jeong, Jin Hwa; Lee, Yong Seuk

2014-08-01

Less mature athletes exhibit biomechanical parameters during cutting maneuvers that may place these athletes at greater risk for injury than their more mature counterparts, especially if the maneuvers are unanticipated. However, most studies on risk factors for anterior cruciate ligament (ACL) injury have focused on neuromuscular and knee kinematic differences between the sexes, not on the biomechanical parameters between specific sporting maneuvers. (1) Anticipation will have a greater effect than the type of cutting maneuver (side- vs cross-cutting) in terms of the biomechanical risk factors for ACL injuries, and (2) the biomechanical risk factors will be different between the 2 types of maneuvers. Controlled laboratory study. Thirty-seven young, male middle school soccer players participated in this study. Three-dimensional motion analysis featuring ground-reaction force and electromyography of the right leg was used. Kinematics, kinetics, and electromyography data for each athlete were analyzed during anticipated and unanticipated side- and cross-cutting maneuvers. The differences between anticipated and unanticipated states as well as between side- and cross-cutting maneuvers were calculated and compared. After unanticipated side-cutting, the time to peak ground-reaction force was longer and peak values were smaller compared with anticipated side-cutting. Flexion, valgus, and internal rotations in the knee joint were larger, and greater flexion and valgus moments were observed. The vastus lateralis and vastus medialis showed lower activity, and the lateral gastrocnemius showed higher activity after unanticipated side-cutting maneuvers. With unanticipated cross-cutting, the time to peak ground-reaction force was longer and peak values were smaller compared with anticipated cross-cutting, and the lateral gastrocnemius showed higher activity. Differences in the peak values of the mediolateral and vertical forces were smaller in the cross-cutting maneuver than in

Aircraft control forces and EMG activity in a C-130 Hercules during strength-critical maneuvers.

PubMed

Hewson, D J; McNair, P J; Marshall, R N

2001-03-01

The force levels required to operate aircraft controls should be readily generated by pilots, without undue fatigue or exertion. However, maximum pilot applied forces, as specified in aircraft design standards, were empirically derived from the subjective comments of test pilots, and may not be applicable for the majority of pilots. Further, experienced RNZAF Hercules flying instructors have indicated that endurance and fatigue are problems for Hercules pilots. The aim of this study was to quantify aircraft control forces during emergency maneuvers in a Hercules aircraft and compare these forces with design standards. In addition, EMG data were recorded as an indicator of muscle fatigue during flight. Six subjects were tested in a C-130 Hercules aircraft. The maneuvers performed were low-level dynamic flight, one engine-off straight-and-level flight, and a two-engines-off simulated approach. The variables recorded were pilot-applied forces and EMG activity. Left rudder pedal force and vastus lateralis activity were both significantly greater during engine-off maneuvers than during low-level dynamic flight (p < 0.05). Maximum aircraft control forces for all controls were within 10% of the design standards. The mean EMG activity across all muscles and maneuvers was 26% MVC, with a peak of 61% MVC in vastus lateralis during the two-engine-off approach. The median frequency of the vastus lateralis EMG signal decreased 13.0% and 16.0% for the one engine-off and two-engine-off maneuvers, respectively. The forces required to fly a Hercules aircraft during emergency maneuvers are similar to the aircraft design standards. However, the levels of vastus lateralis muscle activation observed during the engine-off maneuvers can be sustained for approximately 1 min only. Thus, if two engines fail more than 1 min before landing, pilots may have to alternate control of the aircraft to share the workload and enable the aircraft to land safely.

Development of Skylab experiment T020 employing a foot controlled maneuvering unit

NASA Technical Reports Server (NTRS)

Hewes, D. E.; Glover, K. E.

1972-01-01

A review of the plans and preparations is presented for Skylab experiment T020, entitled Foot-Controlled Maneuvering Unit (FCMU). The FCMU is an experimental system intended to explore the use of simple astronaut maneuvering devices in the zero-gravity environment of space. This review also includes discussions of the FCMU concept and experiment hardware systems, as well as supporting experiment definition and development research studies conducted with the aid of zero-gravity simulators.

Design and analysis of a supersonic penetration/maneuvering fighter

NASA Technical Reports Server (NTRS)

Child, R. D.

1975-01-01

The design of three candidate air combat fighters which would cruise effectively at freestream Mach numbers of 1.6, 2.0, and 2.5 while maintaining good transonic maneuvering capability, is considered. These fighters were designed to deliver aerodynamically controlled dogfight missiles at the design Mach numbers. Studies performed by Rockwell International in May 1974 and guidance from NASA determined the shape and size of these missiles. The principle objective of this study is the aerodynamic design of the vehicles; however, configurations are sized to have realistic structures, mass properties, and propulsion systems. The results of this study show that air combat fighters in the 15,000 to 23,000 pound class would cruise supersonically on dry power and still maintain good transonic maneuvering performance.

Premission and postmission simulation studies of the foot-controlled maneuvering unit for Skylab experiment T-020. [astronaut maneuvering equipment - space environment simulation

NASA Technical Reports Server (NTRS)

Hewes, D. E.; Glover, K. E.

1975-01-01

A Skylab experiment was conducted to study the maneuvering capabilities of astronauts using a relatively simple self-locomotive device, referred to as the foot-controlled maneuvering unit, and to evaluate the effectiveness of ground-based facilities simulating the operation of this device in weightless conditions of space. Some of the special considerations given in the definition and development of the experiment as related to the two ground-based simulators are reviewed. These simulators were used to train the test subjects and to obtain baseline data which could be used for comparison with the in-flight tests that were performed inside the Skylab orbital workshop. The results of both premission and postmission tests are discussed, and subjective comparisons of the in-flight and ground-based test conditions are presented.

Neuroanatomy of the vmPFC and dlPFC predicts individual differences in cognitive regulation during dietary self-control across regulation strategies.

PubMed

Schmidt, Liane; Tusche, Anita; Manoharan, Nicolas; Hutcherson, Cendri; Hare, Todd; Plassmann, Hilke

2018-06-04

Making healthy food choices is challenging for many people. Individuals differ greatly in their ability to follow health goals in the face of temptation, but it is unclear what underlies such differences. Using voxel-based morphometry (VBM), we investigated in healthy humans (i.e., men and women) links between structural variation in gray matter volume and individuals' level of success in shifting toward healthier food choices. We combined MRI and choice data into a joint dataset by pooling across three independent studies that employed a task prompting participants to explicitly focus on the healthiness of food items before making their food choices. Within this dataset, we found that individual differences in gray matter volume in the ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) predicted regulatory success. We extended and confirmed these initial findings by predicting regulatory success out of sample and across tasks in a second dataset requiring participants to apply a different regulation strategy that entailed distancing from cravings for unhealthy, appetitive foods. Our findings suggest that neuroanatomical markers in the vmPFC and dlPFC generalized to different forms of dietary regulation strategies across participant groups. They provide novel evidence that structural differences in neuroanatomy of two key regions for valuation and its control, the vmPFC and dlPFC, predict an individual's ability to exert control in dietary choices. SIGNIFICANCE STATEMENT Dieting involves regulating food choices in order to eat healthier foods and fewer unhealthy foods. People differ dramatically in their ability to achieve or maintain this regulation, but it is unclear why. Here, we show that individuals with more gray matter volume in the dorsolateral and ventromedial prefrontal cortex are better at exercising dietary self-control. This relationship was observed across four different studies examining two different forms of dietary

Capturing and analyzing wheelchair maneuvering patterns with mobile cloud computing.

PubMed

Fu, Jicheng; Hao, Wei; White, Travis; Yan, Yuqing; Jones, Maria; Jan, Yih-Kuen

2013-01-01

Power wheelchairs have been widely used to provide independent mobility to people with disabilities. Despite great advancements in power wheelchair technology, research shows that wheelchair related accidents occur frequently. To ensure safe maneuverability, capturing wheelchair maneuvering patterns is fundamental to enable other research, such as safe robotic assistance for wheelchair users. In this study, we propose to record, store, and analyze wheelchair maneuvering data by means of mobile cloud computing. Specifically, the accelerometer and gyroscope sensors in smart phones are used to record wheelchair maneuvering data in real-time. Then, the recorded data are periodically transmitted to the cloud for storage and analysis. The analyzed results are then made available to various types of users, such as mobile phone users, traditional desktop users, etc. The combination of mobile computing and cloud computing leverages the advantages of both techniques and extends the smart phone's capabilities of computing and data storage via the Internet. We performed a case study to implement the mobile cloud computing framework using Android smart phones and Google App Engine, a popular cloud computing platform. Experimental results demonstrated the feasibility of the proposed mobile cloud computing framework.

Biosynthesis of edeine: II. Localization of edeine synthetase within Bacillus brevis Vm4.

PubMed

Kurylo-Borowska, Z

1975-07-14

Edeine-synthesizing polyenzymes, associated with a complex of sytoplasmic membrane and DNA, were obtained from gently lysed cells of Bacillus brevis Vm4. The polyenzymes-membrane-DNA complex, isolated from dells intensively synthesizing edeines (18--20 h culture) contained edeine B. Edeine B was found to be bound covalently t o the edeine synthetase. The amount of edeine bound to polyenzymes was 0.1--0.3 mumol/mg protein, depending on the age of cells. Detachment of deeine synthetase with a covalently bound edeine B from the membrane-DNA complex was accomplished by a treatment with (NH4)2-SO4 at 45--55% saturation or by DEAE-cellulose column fractionation. In contrast to other components of the complex, the edeine-polyenzymes fragment was not adsorbed to the DEAE-cellulose. Sephadex G-200 column chromatography separated the edeine-polyenzymes complex into 3 fractions. Edeine-polyenzymes complex, obtained from lysozyme-Brij-58-DNAase treated cells, contained edeine B bound to two protein fractions of mol. wt 210 000 and 160 000. Edeine-polyenzymes complex detached from the complex with the membrane and DNA contained edeine B, bound only to protein fraction of mol. wt 210 000. Edeine A was not found in the edeine-polyenzymes complex. No accumulation of free antibiotics within 16--22 h old cells of B. brevis Vm4 was detected. The edeine-polyenzymes complex associated with the DNA-membrane complex has shown no antimicrobial activity. By treating of above with alkali, edeine B of specific activity: 80 units/mjmol was released. The complex of DNA-membrane associated with edeine-polyenzymes complex was able to synthesize DNA, under the conditions described for synthesis, directed by a DNA-membrane complex. Edeine when associated with this complex did not effect the DNA-synthesizing activity.

Development and flight test of an experimental maneuver autopilot for a highly maneuverable aircraft

NASA Technical Reports Server (NTRS)

Duke, Eugene L.; Jones, Frank P.; Roncoli, Ralph B.

1986-01-01

This report presents the development of an experimental flight test maneuver autopilot (FTMAP) for a highly maneuverable aircraft. The essence of this technique is the application of an autopilot to provide precise control during required flight test maneuvers. This newly developed flight test technique is being applied at the Dryden Flight Research Facility of NASA Ames Research Center. The FTMAP is designed to increase the quantity and quality of data obtained in test flight. The technique was developed and demonstrated on the highly maneuverable aircraft technology (HiMAT) vehicle. This report describes the HiMAT vehicle systems, maneuver requirements, FTMAP development process, and flight results.

Manned maneuvering unit technology survey

NASA Technical Reports Server (NTRS)

Cook, G. V. O. (Editor)

1975-01-01

The preliminary design of the manned maneuvering unit (MMU) for the shuttle is investigated, and the current state of the art in certain technology areas that may find application on the operational EVA shuttle MMU is examined. Three broad areas of technology, namely: (1) mechanical energy storage - i.e., the practicality of utilizing the energy storage capability of either a reaction wheel or a control moment gyro, (2) numerical and alphanumerical displays, and (3) recent electronics developments such as microprocessors and integrated injection logic, were covered.

Cassini-Huygens Maneuver Experience: First Year of the Equinox Mission

NASA Technical Reports Server (NTRS)

Gist, Emily M.; Ballard, Christopher G.; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, Powtawche N.

2009-01-01

The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year cruise, it entered a Saturnian orbit for a four-year, prime mission. Due to the success of the prime mission, spacecraft health, and remaining propellant, a two-year extended mission, the Equinox Mission, was approved. Maneuver designs and analyses performed through the first year of the Equinox Mission are presented. Results for the 46 most recent maneuvers are given. A substantial contribution to the navigation success of the Cassini-Huygens spacecraft is the continued accurate performance, which has exceeded the pre-launch expectations and requirements.

Utility of Water Siphon Maneuver for Eliciting Gastroesophageal Reflux During Barium Esophagography: Correlation With Histologic Findings.

PubMed

Dane, B; Doshi, A; Khan, A; Megibow, A

2018-06-12

The objective of this study is to evaluate whether the water siphon maneuver improves detection of gastroesophageal (GE) reflux during barium esophagography compared with observation for spontaneous reflux only. Histopathologic analysis is the reference standard. This retrospective study assessed 87 outpatients who underwent both barium esophagography and upper endoscopy-guided biopsy within a 30-day interval. The water siphon maneuver was routinely performed when spontaneous GE reflux was not observed during the fluoroscopic study. Radiology reports were reviewed for mentions of the presence of reflux and the circumstances in which it was observed (as a spontaneous occurrence or as a result of the water siphon maneuver). Pathology reports from subsequent endoscopic biopsies were reviewed to identify histologic changes of reflux disease. The sensitivity, specificity, and accuracy of esophagography, observation for spontaneous reflux, and the water siphon maneuver were calculated and then compared using a McNemar test. Of the 87 patients, 57 (65.5%) had GE reflux diagnosed on the basis of histologic changes noted on endoscopy, and 30 (34.5%) did not. A total of 57 patients (65.5%) showed reflux during esophagography, 41 (71.9%) of whom had reflux diagnosed by the water siphon maneuver, and 16 (28.1%) had reflux diagnosed on the basis of observation of spontaneous reflux. Forty-four patients had reflux diagnosed on the basis of both a barium study and histologic findings; 13 patients had reflux noted on esophagography but had negative histologic findings. The overall sensitivity, specificity, and accuracy of esophagography for reflux were 77.2%, 56.7%, and 70.1%, respectively. Spontaneous reflux alone had a sensitivity, specificity, and accuracy of 21.1%, 86.7%, and 43.7%, respectively. The water siphon maneuver showed a sensitivity of 71.1%, a specificity of 65.4%, and accuracy of 69.0%. The differences in the sensitivity, specificity, and accuracy of the water

14 CFR 27.337 - Limit maneuvering load factor.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit maneuvering load factor. 27.337 Section 27.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads § 27.337...

Echocardiographic diagnosis of rare pathological patterns of sinus of Valsalva aneurysm

PubMed Central

Wang, Xinfang; Lü, Qing; He, Lin; Wang, Jing; Wang, Bin; Li, Ling; Yuan, Li; Liu, Jinfeng; Ge, Shuping; Xie, Mingxing

2017-01-01

Objective To evaluate the value and improve the diagnostic accuracy of echocardiography in the diagnosis of a sinus of Valsalva aneurysm (SVA) with rare pathological patterns. Methods Echocardiographic features and surgical findings from 270 Chinese patients with SVA treated in the last 18 years (1995–2013) at the Union Hospital were compared retrospectively; 22 of 270 cases had rare patterns. Results The patients with SVA, a rare origin, a rare extending position, or a rare course accounted for 3.4%, 7.4%, and 0.4% of the 270 cases, respectively. The three most common aneurysmal complications of the patients with rare patterns were severe aortic regurgitation (16), obstruction of the ventricular outflow tract or valvular orifice (3), and conduction disturbance (3). The origin, course, extending position and rupture status of the SVAs determined by echocardiography were entirely consistent with surgical findings in 81.8% of the 22 cases. With the exception of one failed diagnosis of an aneurysmal wall dissection and one misdiagnosis of a descending aortic dissection, the echocardiographic results of SVA complications and associated cardiovascular lesions were also confirmed. Conclusion We could accurately diagnose SVAs with rare pathological patterns by echocardiographic identification of distinguishing features. However, for several conditions, we could not accurately identify the origin or course of the aneurysm or define its relationship to adjacent structures using conventional echocardiography alone. Therefore, we recommend combining conventional echocardiography with different imaging techniques, such as transesophageal echocardiography, three-dimensional echocardiography, computed tomography angiography, and aortic angiography. PMID:28291779

The manned maneuvering unit flight controller arm

NASA Astrophysics Data System (ADS)

Falkner, K. E.

1983-05-01

The Manned Maneuvering Unit (MMU) and its support equipment provide an extravehicular astronaut mobility, and the ability to work outside the confines of the Shuttle Orbiter payload bay. The MMU design requirements are based on the highly successful Skylab M-509 maneuvering unit. Design of the MMU was started as an R&D effort in April 1975 and Flight Hardware design was started in August 1979 to support a possible requirement for in-space inspection and repair of Orbiter thermal protection tiles. Subsequently, the qualification test and production activities were slowed, and the current projected earliest first flight is now STS-11 in January, 1984. The MMU propulsion subsystem provides complete redundancy with two identical "system". Each system contains a high pressure gaseous nitrogen tank, an isolation valve, a regulator, and twelve 1.7 lbf (7.5 N) thrusters. The thrusters are packaged to provide the crew member six-degree-of-freedom control in response to commands from translational and rotational hand controllers. This paper discusses the MMU control arm requirements, design, and developmental history.

Slew maneuvers on the SCOLE Laboratory Facility

NASA Technical Reports Server (NTRS)

Williams, Jeffrey P.

1987-01-01

The Spacecraft Control Laboratory Experiment (SCOLE) was conceived to provide a physical test bed for the investigation of control techniques for large flexible spacecraft. The control problems studied are slewing maneuvers and pointing operations. The slew is defined as a minimum time maneuver to bring the antenna line-of-sight (LOS) pointing to within an error limit of the pointing target. The second objective is to rotate about the LOS within the 0.02 degree error limit. The SCOLE problem is defined as two design challenges: control laws for a mathematical model of a large antenna attached to the Space Shuttle by a long flexible mast; and a control scheme on a laboratory representation of the structure modelled on the control laws. Control sensors and actuators are typical of those which the control designer would have to deal with on an actual spacecraft. Computational facilities consist of microcomputer based central processing units with appropriate analog interfaces for implementation of the primary control system, and the attitude estimation algorithm. Preliminary results of some slewing control experiments are given.

Large-angle slewing maneuvers for flexible spacecraft

NASA Technical Reports Server (NTRS)

Chun, Hon M.; Turner, James D.

1988-01-01

A new class of closed-form solutions for finite-time linear-quadratic optimal control problems is presented. The solutions involve Potter's solution for the differential matrix Riccati equation, which assumes the form of a steady-state plus transient term. Illustrative examples are presented which show that the new solutions are more computationally efficient than alternative solutions based on the state transition matrix. As an application of the closed-form solutions, the neighboring extremal path problem is presented for a spacecraft retargeting maneuver where a perturbed plant with off-nominal boundary conditions now follows a neighboring optimal trajectory. The perturbation feedback approach is further applied to three-dimensional slewing maneuvers of large flexible spacecraft. For this problem, the nominal solution is the optimal three-dimensional rigid body slew. The perturbation feedback then limits the deviations from this nominal solution due to the flexible body effects. The use of frequency shaping in both the nominal and perturbation feedback formulations reduces the excitation of high-frequency unmodeled modes. A modified Kalman filter is presented for estimating the plant states.

Optimal Variable-Structure Control Tracking of Spacecraft Maneuvers

NASA Technical Reports Server (NTRS)

Crassidis, John L.; Vadali, Srinivas R.; Markley, F. Landis

1999-01-01

An optimal control approach using variable-structure (sliding-mode) tracking for large angle spacecraft maneuvers is presented. The approach expands upon a previously derived regulation result using a quaternion parameterization for the kinematic equations of motion. This parameterization is used since it is free of singularities. The main contribution of this paper is the utilization of a simple term in the control law that produces a maneuver to the reference attitude trajectory in the shortest distance. Also, a multiplicative error quaternion between the desired and actual attitude is used to derive the control law. Sliding-mode switching surfaces are derived using an optimal-control analysis. Control laws are given using either external torque commands or reaction wheel commands. Global asymptotic stability is shown for both cases using a Lyapunov analysis. Simulation results are shown which use the new control strategy to stabilize the motion of the Microwave Anisotropy Probe spacecraft.

Visual display aid for orbital maneuvering - Design considerations

NASA Technical Reports Server (NTRS)

Grunwald, Arthur J.; Ellis, Stephen R.

1993-01-01

This paper describes the development of an interactive proximity operations planning system that allows on-site planning of fuel-efficient multiburn maneuvers in a potential multispacecraft environment. Although this display system most directly assists planning by providing visual feedback to aid visualization of the trajectories and constraints, its most significant features include: (1) the use of an 'inverse dynamics' algorithm that removes control nonlinearities facing the operator, and (2) a trajectory planning technique that separates, through a 'geometric spreadsheet', the normally coupled complex problems of planning orbital maneuvers and allows solution by an iterative sequence of simple independent actions. The visual feedback of trajectory shapes and operational constraints, provided by user-transparent and continuously active background computations, allows the operator to make fast, iterative design changes that rapidly converge to fuel-efficient solutions. The planning tool provides an example of operator-assisted optimization of nonlinear cost functions.

State Estimation for Landing Maneuver on High Performance Aircraft

NASA Astrophysics Data System (ADS)

Suresh, P. S.; Sura, Niranjan K.; Shankar, K.

2018-01-01

State estimation methods are popular means for validating aerodynamic database on aircraft flight maneuver performance characteristics. In this work, the state estimation method during landing maneuver is explored for the first of its kind, using upper diagonal adaptive extended Kalman filter (UD-AEKF) with fuzzy based adaptive tunning of process noise matrix. The mathematical model for symmetrical landing maneuver consists of non-linear flight mechanics equation representing Aircraft longitudinal dynamics. The UD-AEKF algorithm is implemented in MATLAB environment and the states with bias is considered to be the initial conditions just prior to the flare. The measurement data is obtained from a non-linear 6 DOF pilot in loop simulation using FORTRAN. These simulated measurement data is additively mixed with process and measurement noises, which are used as an input for UD-AEKF. Then, the governing states that dictate the landing loads at the instant of touch down are compared. The method is verified using flight data wherein, the vertical acceleration at the aircraft center of gravity (CG) is compared. Two possible outcome of purely relying on the aircraft measured data is highlighted. It is observed that, with the implementation of adaptive fuzzy logic based extended Kalman filter tuned to adapt for aircraft landing dynamics, the methodology improves the data quality of the states that are sourced from noisy measurements.

Computing and Visualizing Reachable Volumes for Maneuvering Satellites

NASA Astrophysics Data System (ADS)

Jiang, M.; de Vries, W.; Pertica, A.; Olivier, S.

2011-09-01

Detecting and predicting maneuvering satellites is an important problem for Space Situational Awareness. The spatial envelope of all possible locations within reach of such a maneuvering satellite is known as the Reachable Volume (RV). As soon as custody of a satellite is lost, calculating the RV and its subsequent time evolution is a critical component in the rapid recovery of the satellite. In this paper, we present a Monte Carlo approach to computing the RV for a given object. Essentially, our approach samples all possible trajectories by randomizing thrust-vectors, thrust magnitudes and time of burn. At any given instance, the distribution of the "point-cloud" of the virtual particles defines the RV. For short orbital time-scales, the temporal evolution of the point-cloud can result in complex, multi-reentrant manifolds. Visualization plays an important role in gaining insight and understanding into this complex and evolving manifold. In the second part of this paper, we focus on how to effectively visualize the large number of virtual trajectories and the computed RV. We present a real-time out-of-core rendering technique for visualizing the large number of virtual trajectories. We also examine different techniques for visualizing the computed volume of probability density distribution, including volume slicing, convex hull and isosurfacing. We compare and contrast these techniques in terms of computational cost and visualization effectiveness, and describe the main implementation issues encountered during our development process. Finally, we will present some of the results from our end-to-end system for computing and visualizing RVs using examples of maneuvering satellites.

Relationship between intra-abdominal pressure and vaginal wall movements during Valsalva in women with and without pelvic organ prolapse: technique development and early observations.

PubMed

Spahlinger, D M; Newcomb, L; Ashton-Miller, J A; DeLancey, J O L; Chen, Luyun

2014-07-01

To develop and test a method for measuring the relationship between the rise in intra-abdominal pressure and sagittal plane movements of the anterior and posterior vaginal walls during Valsalva in a pilot sample of women with and without prolapse. Mid-sagittal MRI images were obtained during Valsalva while changes in intra-abdominal pressure were measured via a bladder catheter in 5 women with cystocele, 5 women with rectocele, and 5 controls. The regional compliance of the anterior and posterior vagina wall support systems were estimated from the ratio of displacement (mm) of equidistant points along the anterior and posterior vaginal walls to intra-abdominal pressure rise (mmHg). The compliance of both anterior and posterior vaginal wall support systems varied along different regions of vaginal wall for all three groups, with the highest compliance found near the vaginal apex and the lowest near the introitus. Women with cystocele had more compliant anterior and posterior vaginal wall support systems than women with rectocele. The movement direction differs between cystocele and rectocele. In cystocele, the anterior vaginal wall moves mostly toward the vaginal orifice in the upper vagina, but in a ventral direction in the lower vagina. In rectocele, the direction of the posterior vaginal wall movement is generally toward the vaginal orifice. Movement of the vaginal wall and compliance of its support is quantifiable and was found to vary along the length of the vagina. Compliance was greatest in the upper vagina of all groups. Women with cystocele demonstrated the most compliant vaginal wall support.

Knee biomechanics during a jump-cut maneuver: Effects of gender & ACL surgery

PubMed Central

Miranda, Daniel L.; Fadale, Paul D.; Hulstyn, Michael J.; Shalvoy, Robert M.; Machan, Jason T.; Fleming, Braden C.

2012-01-01

Purpose The purpose of this study was to compare kinetic and knee kinematic measurements from male and female ACL-intact (ACLINT) and ACL-reconstructed (ACLREC) subjects during a jump-cut maneuver using biplanar videoradiography. Methods Twenty subjects were recruited; 10 ACLINT (5 males, 5 females) and 10 ACLREC (4 males, 6 females; five years post surgery). Each subject performed a jump-cut maneuver by landing on a single leg and performing a 45° side-step cut. Ground reaction force was measured by a force plate and expressed relative to body weight. Six-degree-of-freedom knee kinematics were determined from a biplanar videoradiography system and an optical motion capture system. Results ACLINT female subjects landed with a larger peak vertical GRF (p<0.001) compared to ACLINT male subjects. ACLINT subjects landed with a larger peak vertical GRF (p≤0.036) compared to ACLREC subjects. Regardless of ACL reconstruction status, female subjects underwent less knee flexion angle excursion (p=0.002) and had an increased average rate of anterior tibial translation (0.05±0.01%/millisecond; p=0.037) after contact compared to male subjects. Furthermore, ACLREC subjects had a lower rate of anterior tibial translation compared to ACLINT subjects (0.05±0.01%/millisecond; p=0.035). Finally, no striking differences were observed in other knee motion parameters. Conclusion Women permit a smaller amount of knee flexion angle excursion during a jump-cut maneuver, resulting in a larger peak vertical GRF and increased rate of anterior tibial translation. Notably, ACLREC subjects also perform the jump cut maneuver with lower GRF than ACLINT subjects five years post surgery. This study proposes a causal sequence whereby increased landing stiffness (larger peak vertical GRF combined with less knee flexion angle excursion) leads to an increased rate of anterior tibial translation while performing a jump-cut maneuver. PMID:23190595

Geostationary Collocation: Case Studies for Optimal Maneuvers

DTIC Science & Technology

2016-03-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited GEOSTATIONARY ...DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE GEOSTATIONARY COLLOCATION: CASE STUDIES FOR OPTIMAL MANEUVERS 5. FUNDING NUMBERS 6...The geostationary belt is considered a natural resource, and as time goes by, the physical spaces for geostationary satellites will run out. The

FBK Optical Data Association in a Multi-Hypothesis Framework with Maneuvers

NASA Astrophysics Data System (ADS)

Faber, W. R.; Hussein, I. I.; Kent, J. T.; Bhattacharjee, S. Jah, M. K.

In Space Situational Awareness (SSA), one may encounter scenarios where the measurements received at a certain time do not correlate to a known Resident Space Object (RSO). Without information that uniquely assigns the measurement to a particular RSO there can be no certainty on the identity of the object. It could be that the measurement was produced by clutter or perhaps a newly birthed RSO. It is also a possibility that the measurement came from a previously known object that maneuvered away from its predicted location. Typically, tracking methods tend to associate uncorrelated measurements to new objects and wait for more information to determine the true RSO population. This can lead to the loss of object custody. The goal of this paper is to utilize a multiple hypothesis framework coupled with some knowledge of RSO maneuvers that allows the user to maintain object custody in scenarios with uncorrelated optical measurement returns. This is achieved by fitting a Fisher-Bingham-Kent type distribution to the hypothesized maneuvers for accurate data association using directional discriminant analysis.

Hydrology of the U.S. Army Pinon Canyon maneuver site, Las Animas County, Colorado

USGS Publications Warehouse

Von Guerard, Paul; Abbott, P.O.; Nickless, Raymond C.

1987-01-01

The U.S. Department of the Army (Fort Carson Military Reservation) has acquired 381 sq mi of semiarid rangeland in southeastern Colorado for mechanized military maneuvers. The study area, known as the Pinon Canyon Maneuver Site, drains into the Purgatoire River, a major tributary of the upper Arkansas River. A multidisciplined hydrologic investigation began in October 1982. The primary aquifer in the Maneuver Site is the Dakota-Purgatoire. Well yields generally range from 10 to 500 gal/min. Dissolved solids concentrations in groundwater ranged from 195 to 6,150 mg/L. Streamflow in the Purgatoire River is perennial. Tributaries draining the Maneuver Site are intermittent or ephemeral and contribute only about 4.4% of the streamflow of the Purgatoire River downstream from the Maneuver Site. Flood frequencies were calculated by using the log Pearson III procedure and compared well with a regional estimating technique that was developed that uses physical drainage-basin characteristics. Calcium and sulfate are the predominant ions in the surface water of the area. Time-series plots indicate that instream water-quality standards for nitrate and metals are exceeded. About 80% of the suspended-sediment load is transported by rainfall runoff, which occurs less than 8% of the time. Ephermal tributaries contributed less than 25% of the suspended-sediment load transported to the Purgatoire River downstream from the Maneuver Site. Historic annual mean sediment yields were measured for 29 small watersheds. Sediment yields were measured for 29 small watersheds. Sediment yields ranged from 9.5 to 1,700 tons/sq mi. Sediment yields were estimated by a multiple-linear-regression model developed by using physical drainage-basin characteristics and by the Pacific Southwest Interagency Committee method. (USGS)

Structural Dynamics of Maneuvering Aircraft.

DTIC Science & Technology

1987-09-01

MANDYN. Written in Fortran 77, it was compiled and executed with Microsoft Fortran, Vers. 4.0 on an IBM PC-AT, with a co-processor, and a 20M hard disk...to the pivot area. Pre- sumably, the pivot area is a hard point in the wing structure. -41- NADC M1i4-0 ResulIts The final mass and flexural rigidity...lowest mode) is an important parameter. If it is less than three, the load factor approach can be problema - tical. In assessing the effect of one maneuver

Accidental death in autoerotic maneuvers.

PubMed

Focardi, Martina; Gualco, Barbara; Norelli, GianAristide

2008-03-01

The authors from the Florence Forensic Department present a case that demonstrates the paradigms attached to accidental deaths while performing autoerotic maneuvers. The incidents of such practices are underestimated and are only the tip of the iceberg since they do not represent the cases that are never reported due to successful practice. After analyzing the statistic data, the authors describe the case and discuss about the element that prove the accidental nature of the death and the importance of the correct application of forensic methodology at the scene and in the mortuary.

Preparing GMAT for Operational Maneuver Planning of the Advanced Composition Explorer (ACE)

NASA Technical Reports Server (NTRS)

Qureshi, Rizwan Hamid; Hughes, Steven P.

2014-01-01

The General Mission Analysis Tool (GMAT) is an open-source space mission design, analysis and trajectory optimization tool. GMAT is developed by a team of NASA, private industry, public and private contributors. GMAT is designed to model, optimize and estimate spacecraft trajectories in flight regimes ranging from low Earth orbit to lunar applications, interplanetary trajectories and other deep space missions. GMAT has also been flight qualified to support operational maneuver planning for the Advanced Composition Explorer (ACE) mission. ACE was launched in August, 1997 and is orbiting the Sun-Earth L1 libration point. The primary science objective of ACE is to study the composition of both the solar wind and the galactic cosmic rays. Operational orbit determination, maneuver operations and product generation for ACE are conducted by NASA Goddard Space Flight Center (GSFC) Flight Dynamics Facility (FDF). This paper discusses the entire engineering lifecycle and major operational certification milestones that GMAT successfully completed to obtain operational certification for the ACE mission. Operational certification milestones such as gathering of the requirements for ACE operational maneuver planning, gap analysis, test plans and procedures development, system design, pre-shadow operations, training to FDF ACE maneuver planners, shadow operations, Test Readiness Review (TRR) and finally Operational Readiness Review (ORR) are discussed. These efforts have demonstrated that GMAT is flight quality software ready to support ACE mission operations in the FDF.

Gender differences in hip adduction motion and torque during a single-leg agility maneuver.

PubMed

Hewett, Timothy E; Ford, Kevin R; Myer, Gregory D; Wanstrath, Kim; Scheper, Melia

2006-03-01

The purpose of this study was to identify gender differences in hip motion and kinetics during a single leg bidirectional deceleration maneuver. The rationale for the development of this maneuver was to test dynamic hip control during the deceleration of three different types of single-leg landings. The hypothesis was that female athletes would display increased hip adduction angles and moments during the maneuver compared to male athletes. Thirty-six collegiate soccer players (19 female, 17 male) volunteered to participate. Subjects were instructed to start the maneuver balancing on one foot, to hop through an agility-speed ladder on the same leg "up two boxes, back one, and then up one and hold it." Hip kinematics and kinetics during all three landings were examined. Females demonstrated significantly greater hip adduction angles at initial contact during all three landings and greater maximal hip adduction during landings 1 and 2 compared to male athletes. Females also exhibited significantly increased external hip adduction moments during landing 1, however, no differences were found between genders during landings 2 and 3. Copyright 2006 Orthopaedic Research Society.

Control of a high beta maneuvering reentry vehicle using dynamic inversion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watts, Alfred Chapman

2005-05-01

The design of flight control systems for high performance maneuvering reentry vehicles presents a significant challenge to the control systems designer. These vehicles typically have a much higher ballistic coefficient than crewed vehicles like as the Space Shuttle or proposed crew return vehicles such as the X-38. Moreover, the missions of high performance vehicles usually require a steeper reentry flight path angle, followed by a pull-out into level flight. These vehicles then must transit the entire atmosphere and robustly perform the maneuvers required for the mission. The vehicles must also be flown with small static margins in order to performmore » the required maneuvers, which can result in highly nonlinear aerodynamic characteristics that frequently transition from being aerodynamically stable to unstable as angle of attack increases. The control system design technique of dynamic inversion has been applied successfully to both high performance aircraft and low beta reentry vehicles. The objective of this study was to explore the application of this technique to high performance maneuvering reentry vehicles, including the basic derivation of the dynamic inversion technique, followed by the extension of that technique to the use of tabular trim aerodynamic models in the controller. The dynamic inversion equations are developed for high performance vehicles and augmented to allow the selection of a desired response for the control system. A six degree of freedom simulation is used to evaluate the performance of the dynamic inversion approach, and results for both nominal and off nominal aerodynamic characteristics are presented.« less

Security in the CernVM File System and the Frontier Distributed Database Caching System

NASA Astrophysics Data System (ADS)

Dykstra, D.; Blomer, J.

2014-06-01

Both the CernVM File System (CVMFS) and the Frontier Distributed Database Caching System (Frontier) distribute centrally updated data worldwide for LHC experiments using http proxy caches. Neither system provides privacy or access control on reading the data, but both control access to updates of the data and can guarantee the authenticity and integrity of the data transferred to clients over the internet. CVMFS has since its early days required digital signatures and secure hashes on all distributed data, and recently Frontier has added X.509-based authenticity and integrity checking. In this paper we detail and compare the security models of CVMFS and Frontier.

Astronaut Alan Bean flies the Astronaut Maneuvering Equipment in the OWS

NASA Image and Video Library

1973-08-28

S73-34207 (28 Aug. 1973) --- Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 astronaut Maneuvering Equipment, as seen in this photographic reproduction taken from a television transmission made by a color television camera in the Orbital Workshop (OWS) of the Skylab space station in Earth orbit. Bean is strapped into the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). The M509 exercise was in the forward dome area of the OWS. The dome area is about 22 feet in diameter and 19 feet from top to bottom. Photo credit: NASA

Docking simulation analysis of range data requirements for the orbital maneuvering vehicle

NASA Technical Reports Server (NTRS)

Micheal, J. D.; Vinz, F. L.

1985-01-01

The results of an initial study are reported assess the controllability of the Orbital Maneuvering Vehicle (OMV) for terminal closure and docking are reported. The vehicle characteristics used in this study are those of the Marshall Space Flight Center (MSFC) baseline OMV which were published with the request for proposals for preliminary design of this vehicle. This simulation was conducted at MSFC using the Target Motion Simulator. The study focused on the OMV manual mode capability to accommodate both stabilized and tumbling target engagements with varying complements of range and range rate data displayed to the OMV operator. Four trained test subjects performed over 400 simulated orbital dockings during this study. A firm requirement for radar during the terminal closure and dock phase of the OMV mission was not established by these simulations. Fifteen pound thrusters recommended in the MSFC baseline design were found to be advantageous for initial rate matching maneuvers with unstabilized targets; however, lower thrust levels were desirable for making the final docking maneuvers.

Sinus of Valsalva Fistula to the Right Ventricle along with Coronary Artery Fistula to the Pulmonary Artery in a Young Native American Female

PubMed Central

Desai, Sarika; Loli, Akil; Maki, Peter

2013-01-01

Sinus of Valsalva aneurysm is a rare condition and associated with a high rate of mortality if rupture occurs. The aneurysms are rarely diagnosed until rupture occurs. This case describes a young Native American female whose only symptom was intermittent chest pain prior to the detection of the aneurysm along with a small ventricular septal defect. The patient was also found to have a coexisting coronary artery fistula, and it is rare phenomenon to have these coexisting anomalies. The anomalies were demonstrated on both cardiac computed tomography and coronary angiography. The patient underwent surgical closure of both anomalies, which is the recommended treatment to avoid future complications. PMID:24804114

Sinus of Valsalva Fistula to the Right Ventricle along with Coronary Artery Fistula to the Pulmonary Artery in a Young Native American Female.

PubMed

Desai, Sarika; Flores, Erica; Loli, Akil; Maki, Peter

2013-01-01

Sinus of Valsalva aneurysm is a rare condition and associated with a high rate of mortality if rupture occurs. The aneurysms are rarely diagnosed until rupture occurs. This case describes a young Native American female whose only symptom was intermittent chest pain prior to the detection of the aneurysm along with a small ventricular septal defect. The patient was also found to have a coexisting coronary artery fistula, and it is rare phenomenon to have these coexisting anomalies. The anomalies were demonstrated on both cardiac computed tomography and coronary angiography. The patient underwent surgical closure of both anomalies, which is the recommended treatment to avoid future complications.

Kristeller maneuvers or fundal pressure and maternal/neonatal morbidity: obstetric and judicial literature review.

PubMed

Malvasi, Antonio; Zaami, Simona; Tinelli, Andrea; Trojano, Giuseppe; Montanari Vergallo, Gianluca; Marinelli, Enrico

2018-02-21

A significant amount of data concerning maternal-fetal damage arising from the exertion of Kristeller maneuvers (KMs) or fundal pressure (FP) go unreleased due to medicolegal implications. For this reason, the paper gathers information as to the real magnitude of litigation related to FP-induced damages and injuries. The authors have undertaken a research in order to include general search engines (PubMed-Medline, Cochrane, Embase, Google, GyneWeb) and legal databases (De Jure, Italian database of jurisprudence daily update; Westlaw, Thomson Reuters, American ruling database and Bailii, UK Court Ruling Database). Results confirm said phenomenon to be more wide ranging than it appears through official channels. Several courts of law, both in the United States of America (USA) and in European Union (EU) Member States as well, have ruled against the use of the maneuver itself, assuming a stance conducive to a presumption of guilt against those doctors and healthcare providers who resorted to KMs or FP during deliveries. Given how rife FP is in mainstream obstetric practice, it is as if there were a wide gap between obstetric real-life and what official jurisprudence and healthcare institutions-sanctioned official practices are. The authors think that it would be desirable to draft specifically targeted guidelines or recommendations on maneuvers during vaginal delivery, in which to point out exactly what kinds of maneuvering techniques are to be absolutely banned and what maneuvers are to be allowed, and under what conditions their application can be considered appropriate.

Adaptive lyapunov control and artificial neural networks for spacecraft relative maneuvering using atmospheric differential drag

NASA Astrophysics Data System (ADS)

Perez Chaparro, David Andres

At low Earth orbits, a differential in the drag acceleration between spacecraft can be used to control their relative motion. This drag differential allows for a propellant-free alternative to thrusters for performing relative maneuvers in these orbits. The interest in autonomous propellant-less maneuvering comes from the desire to reduce the costs of spacecraft formations. Formation maneuvering opens up a wide variety of new applications for spacecraft missions, such as on-orbit maintenance and refueling. In this work atmospheric differential drag based nonlinear controllers are presented that can be used for virtually any planar relative maneuver of two spacecraft, provided that there is enough atmospheric density and that the spacecraft can change their ballistic coefficients by sufficient amounts to generate the necessary differential accelerations. The control techniques are successfully tested using high fidelity Satellite Tool Kit simulations for re-phase, fly-around, and rendezvous maneuvers, proving the feasibility of the proposed approach for a real flight. Furthermore, the atmospheric density varies in time and in space as the spacecraft travel along their orbits. The ability to accurately forecast the density allows for accurate onboard orbit propagation and for creating realistic guidance trajectories for maneuvers that rely on the differential drag. In this work a localized density predictor based on artificial neural networks is also presented. The predictor uses density measurements or estimates along the past orbits and can use a set of proxies for solar and geomagnetic activities to predict the value of the density along the future orbits of the spacecraft. The performance of the localized predictor is studied for different neural network structures, testing periods of high and low solar and geomagnetic activities and different prediction windows. Comparison with previously developed methods show substantial benefits in using neural networks, both

Maintaining Aura's Orbit Requirements While Performing Orbit Maintenance Maneuvers Containing an Orbit Normal Delta-V Component

NASA Technical Reports Server (NTRS)

Johnson, Megan R.; Petersen, Jeremy D.

2014-01-01

The Earth Observing System (EOS) Afternoon Constellation consists of five member missions (GCOM-W1, Aqua, CALIPSO, CloudSat, and Aura), each of which maintain a frozen, sun-synchronous orbit with a 16-day repeating ground track that follows the Worldwide Reference System-2 (WRS-2). Under nominal science operations for Aura, the propulsion system is oriented such that the resultant thrust vector is aligned 13.493 degrees away from the velocity vector along the yaw axis. When performing orbit maintenance maneuvers, the spacecraft performs a yaw slew to align the thrust vector in the appropriate direction. A new Drag Make Up (DMU) maneuver operations scheme has been implemented for Aura alleviating the need for the 13.493 degree yaw slew. The focus of this investigation is to assess the impact that no-slew DMU maneuver operations will have on Aura's Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Aura's frozen orbit properties, eccentricity and argument of perigee. Seven maneuver strategies were analyzed to determine the best operational approach. A mirror pole strategy, with maneuvers alternating at the North and South poles, was implemented operationally to minimize impact to the MLT. Additional analysis determined that the mirror pole strategy could be further modified to include frozen orbit maneuvers and thus maintain both MLT and the frozen orbit properties under noslew operations.

Piloted Parameter Identification Flight Test Maneuvers for Closed Loop Modeling of the F-18 High Alpha Research Vehicle (HARV)

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.

1996-01-01

Flight test maneuvers are specified for the F-18 High Alpha Research Vehicle (HARV). The maneuvers were designed for closed loop parameter identification purposes, specifically for longitudinal and lateral linear model parameter estimation at 5, 20, 30, 45, and 60 degrees angle of attack, using the NASA 1A control law. Each maneuver is to be realized by the pilot applying square wave inputs to specific pilot station controls. Maneuver descriptions and complete specifications of the time/amplitude points defining each input are included, along with plots of the input time histories.

Near Earth Asteroid redirect missions based on gravity assist maneuver

NASA Astrophysics Data System (ADS)

Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

During last years several events attracted world community attention to the hazards of hitting the Earth by sky objects. One of these objects is Apophis asteroid what was expected with nonzero probability to hit the Earth in 2036. Luckily after more precise measurements this event is considered as practically improbable. But the other object has really reached the Earth, entered the atmosphere in the Chelyabinsk area and caused vast damages. After this the hazardous near Earth objects problem received practical confirmation of the necessity to find the methods of its resolution. The methods to prevent collision of the dangerous sky object with the Earth proposed up to now look not practical enough if one mentions such as gravitational tractor or changing the reflectivity of the asteroid surface. Even the method supposing the targeting of the spacecraft to the hazardous object in order to deflect it from initial trajectory by impact does not work because its low mass as compared with the mass of asteroid to be deflected. For example the mass of the Apophis is estimated to be about 40 million tons but the spacecraft which can be launched to intercept the asteroid using contemporary launchers has the mass not more than 5 tons. So the question arises where to find the heavier projectile which is possible to direct to the dangerous object? The answer proposed in our paper is very simple: to search it among small near Earth asteroids. As small ones we suppose those which have the cross section size not more than 12-15 meters and mass not exceeding 1500 -1700 tons. According to contemporary estimates the number of such asteroids is not less than 100000. The other question is how to redirect such asteroid to the dangerous one. In the paper the possibilities are studied to use for that purpose gravity assist maneuvers near Earth. It is shown that even among asteroids included in contemporary catalogue there are the ones which could be directed to the trajectory of the

Parameter Identification Flight Test Maneuvers for Closed Loop Modeling of the F-18 High Alpha Research Vehicle (HARV)

NASA Technical Reports Server (NTRS)

Batterson, James G. (Technical Monitor); Morelli, E. A.

1996-01-01

Flight test maneuvers are specified for the F-18 High Alpha Research Vehicle (HARV). The maneuvers were designed for closed loop parameter identification purposes, specifically for longitudinal and lateral linear model parameter estimation at 5,20,30,45, and 60 degrees angle of attack, using the Actuated Nose Strakes for Enhanced Rolling (ANSER) control law in Thrust Vectoring (TV) mode. Each maneuver is to be realized by applying square wave inputs to specific pilot station controls using the On-Board Excitation System (OBES). Maneuver descriptions and complete specifications of the time / amplitude points defining each input are included, along with plots of the input time histories.

Identifying tacit strategies in aircraft maneuvers

NASA Technical Reports Server (NTRS)

Lewis, Charles M.; Heidorn, P. B.

1991-01-01

Two machine-learning methods are presently used to characterize the avoidance strategies used by skilled pilots in simulated aircraft encounters, and a general framework for the characterization of the strategic components of skilled behavior via qualitative representation of situations and responses is presented. Descriptions of pilot maneuvers that were 'conceptually equivalent' were ascertained by a concept-learning algorithm in conjunction with a classifier system that employed a generic algorithm; satisficing and 'buggy' strategies were thereby revealed.

Anatomical basis of the liver hanging maneuver.

PubMed

Trotovsek, Blaz; Belghiti, Jacques; Gadzijev, Eldar M; Ravnik, Dean; Hribernik, Marija

2005-01-01

The anterior approach to right hepatectomy using the liver hanging maneuver without liver mobilization claims to be anatomically evaluated. During this procedure a 4 to 6-cm blind dissection between the inferior vena cava and the liver is performed. Short subhepatic veins, entering the inferior vena cava could be torn and a hemorrhage, difficult to control, could occur. On 100 corrosive casts of livers the anterior surface of the inferior vena cava was studied to evaluate the position, diameter and draining area of short subhepatic veins and inferior right hepatic vein. The width of the narrowest point on the planned route of blind dissection was determined. The average value of the narrowest point on the planned route of blind dissection was 8.7+/-2.3mm (range 2-15mm). The ideal angle of dissection being 0 degrees was found in 93% of cases. In 7% we found the angle of 5 degrees toward the right border of inferior vena cava to be the better choice. Our results show that liver hanging maneuver is a safe procedure. With the dissection in the proposed route the risk of disrupting short subhepatic veins is low (7%).

Kinematic Visual Biofeedback Improves Accuracy of Learning a Swallowing Maneuver and Accuracy of Clinician Cues During Training.

PubMed

Azola, Alba M; Sunday, Kirstyn L; Humbert, Ianessa A

2017-02-01

Submental surface electromyography (ssEMG) visual biofeedback is widely used to train swallowing maneuvers. This study compares the effect of ssEMG and videofluoroscopy (VF) visual biofeedback on hyo-laryngeal accuracy when training a swallowing maneuver. Furthermore, it examines the clinician's ability to provide accurate verbal cues during swallowing maneuver training. Thirty healthy adults performed the volitional laryngeal vestibule closure maneuver (vLVC), which involves swallowing and sustaining closure of the laryngeal vestibule for 2 s. The study included two stages: (1) first accurate demonstration of the vLVC maneuver, followed by (2) training-20 vLVC training swallows. Participants were randomized into three groups: (a) ssEMG biofeedback only, (b) VF biofeedback only, and (c) mixed biofeedback (VF for the first accurate demonstration achieving stage and ssEMG for the training stage). Participants' performances were verbally critiqued or reinforced in real time while both the clinician and participant were observing the assigned visual biofeedback. VF and ssEMG were continuously recorded for all participants. Results show that accuracy of both vLVC performance and clinician cues was greater with VF biofeedback than with either ssEMG or mixed biofeedback (p < 0.001). Using ssEMG for providing real-time biofeedback during training could lead to errors while learning and training a swallowing maneuver.

Effect of different body postures on the pressures generated during an L-1 maneuver.

PubMed

Williams, C A; Lind, A R; Wiley, R L; Douglas, J E; Miller, G

1988-10-01

Changes in blood pressure, intrathoracic pressure, heart rate and the electromyographic activity of various muscle groups were determined while nine male subjects performed 15-s L-1 straining maneuvers at four spine-to-thigh angles (70, 84, 94, and 105 degrees) and two seatback angles (30 and 60 degrees). There was no significant difference between the changes in these variables due to the different body positions. At the onset of the L-1, arterial pressure immediately increased to 195 +/- 5 mm Hg, but fell progressively during the next 5 s to 160 +/- 5 mm Hg. It remained constant during the next 5 s of the maneuver and then recovered to 180 +/- mm Hg during the last 5 s of the maneuver. Esophageal pressure followed essentially the same pattern of response, but heart rate progressively increased during the entire L-1. No one muscle group was utilized more than another. Inflation of an anti-G suit to 4 PSI had no effect on the variables measured. Generation of high arterial pressures during L-1 maneuvers is transitory and not affected either positively or negatively by altering subject body position.

Catheter Entrapment During Posterior Mitral Leaflet Pushing Maneuver for MitraClip Implantation.

PubMed

Castrodeza, Javier; Amat-Santos, Ignacio J; Tobar, Javier; Varela-Falcón, Luis H

2016-06-01

MitraClip (Abbott Vascular) therapy has been reported to be an effective procedure for mitral regurgitation, especially in high-risk patients. Recently, the novel pushing maneuver technique has been described for approaching restricted and short posterior leaflets with a pigtail catheter in order to facilitate grasping of the clip. However, complications or unexpected situations may occur. We report the case of an 84-year-old patient who underwent MitraClip implantation wherein the pushing maneuver was complicated by the clip accidentally gripping the pigtail catheter along with the two leaflets.

Evaluation of lung recruitment maneuvers in acute respiratory distress syndrome using computer simulation.

PubMed

Das, Anup; Cole, Oana; Chikhani, Marc; Wang, Wenfei; Ali, Tayyba; Haque, Mainul; Bates, Declan G; Hardman, Jonathan G

2015-01-12

Direct comparison of the relative efficacy of different recruitment maneuvers (RMs) for patients with acute respiratory distress syndrome (ARDS) via clinical trials is difficult, due to the heterogeneity of patient populations and disease states, as well as a variety of practical issues. There is also significant uncertainty regarding the minimum values of positive end-expiratory pressure (PEEP) required to ensure maintenance of effective lung recruitment using RMs. We used patient-specific computational simulation to analyze how three different RMs act to improve physiological responses, and investigate how different levels of PEEP contribute to maintaining effective lung recruitment. We conducted experiments on five 'virtual' ARDS patients using a computational simulator that reproduces static and dynamic features of a multivariable clinical dataset on the responses of individual ARDS patients to a range of ventilator inputs. Three recruitment maneuvers (sustained inflation (SI), maximal recruitment strategy (MRS) followed by a titrated PEEP, and prolonged recruitment maneuver (PRM)) were implemented and evaluated for a range of different pressure settings. All maneuvers demonstrated improvements in gas exchange, but the extent and duration of improvement varied significantly, as did the observed mechanism of operation. Maintaining adequate post-RM levels of PEEP was seen to be crucial in avoiding cliff-edge type re-collapse of alveolar units for all maneuvers. For all five patients, the MRS exhibited the most prolonged improvement in oxygenation, and we found that a PEEP setting of 35 cm H2O with a fixed driving pressure of 15 cm H2O (above PEEP) was sufficient to achieve 95% recruitment. Subsequently, we found that PEEP titrated to a value of 16 cm H2O was able to maintain 95% recruitment in all five patients. There appears to be significant scope for reducing the peak levels of PEEP originally specified in the MRS and hence to avoid exposing the lung to

Detect and Avoid (DAA) Automation Maneuver Study

DTIC Science & Technology

2017-02-01

88ABW-2017-2261. 14. ABSTRACT The study described herein was an operator–in–the–loop assessment supporting the development of a Sense and Avoid ( SAA ...display that enables effective teaming of an Unmanned Aerial Systems (UAS) operator with an advanced SAA maneuver algorithm to safely avoid proximal...air traffic. This study examined performance differences between candidate SAA display configurations and automation thresholds while UAS operators

Maneuver Acoustic Flight Test of the Bell 430 Helicopter Data Report

NASA Technical Reports Server (NTRS)

Watts, Michael E.; Greenwood, Eric; Smith, Charles D.; Snider, Royce; Conner, David A.

2014-01-01

A cooperative ight test by NASA, Bell Helicopter and the U.S. Army to characterize the steady state acoustics and measure the maneuver noise of a Bell Helicopter 430 aircraft was accomplished. The test occurred during June/July 2011 at Eglin Air Force Base, Florida. This test gathered a total of 410 test points over 10 test days and compiled an extensive database of dynamic maneuver measurements. Three microphone arrays with up to 31 microphon. es in each were used to acquire acoustic data. Aircraft data included Differential Global Positioning System, aircraft state and rotor state information. This paper provides an overview of the test and documents the data acquired.

Proximity Operations for Space Situational Awareness Spacecraft Rendezvous and Maneuvering using Numerical Simulations and Fuzzy Logic

NASA Astrophysics Data System (ADS)

Carrico, T.; Langster, T.; Carrico, J.; Alfano, S.; Loucks, M.; Vallado, D.

The authors present several spacecraft rendezvous and close proximity maneuvering techniques modeled with a high-precision numerical integrator using full force models and closed loop control with a Fuzzy Logic intelligent controller to command the engines. The authors document and compare the maneuvers, fuel use, and other parameters. This paper presents an innovative application of an existing capability to design, simulate and analyze proximity maneuvers; already in use for operational satellites performing other maneuvers. The system has been extended to demonstrate the capability to develop closed loop control laws to maneuver spacecraft in close proximity to another, including stand-off, docking, lunar landing and other operations applicable to space situational awareness, space based surveillance, and operational satellite modeling. The fully integrated end-to-end trajectory ephemerides are available from the authors in electronic ASCII text by request. The benefits of this system include: A realistic physics-based simulation for the development and validation of control laws A collaborative engineering environment for the design, development and tuning of spacecraft law parameters, sizing actuators (i.e., rocket engines), and sensor suite selection. An accurate simulation and visualization to communicate the complexity, criticality, and risk of spacecraft operations. A precise mathematical environment for research and development of future spacecraft maneuvering engineering tasks, operational planning and forensic analysis. A closed loop, knowledge-based control example for proximity operations. This proximity operations modeling and simulation environment will provide a valuable adjunct to programs in military space control, space situational awareness and civil space exploration engineering and decision making processes.

The geometry of high angle of attack maneuvers and the implications for Gy-induced neck injuries.

PubMed

Newman, David G; Ostler, David

2011-08-01

Modern super agile fighter aircraft have significantly expanded maneuverability envelopes, often involving very high angles of attack (AOA) in the post-stall region. One such maneuver is the high AOA velocity vector roll. The geometry of this flight maneuver is such that during the roll there is a significant lateral C load imposed on the unrestrained head-neck complex of the pilot. A mathematical analysis of the geometric relationship determining the magnitude of +/- Gy acceleration during high AOA maneuvering was conducted. This preliminary mathematical model is able to predict the Gy load imposed on the head-neck complex of the pilot for a given set of flight maneuver parameters. The analysis predicts that at an AOA of 700 and with a roll rate of 100 degrees x s(-1), the lateral G developed will be approximately 3.5 Gy. Increasing the roll rate increases the lateral G component: at 200 degrees x s(-1) the Gy, load is more than 6 Gy. There are serious potential implications of super agile maneuvers on the neck of the pilot. The G environment experienced by the pilot of super agile aircraft is increasingly multiaxial, involving +/- Gx, +/- Gy, and +/- Gz. The level of lateral G developed during these dynamic flight maneuvers should not be underestimated, as such G loads can potentially lead to neck injuries. While aircraft become ever more capable, a full understanding of the biodynamic effects on the pilot while exploiting the agility of the aircraft still needs to be developed.

Operational Implications of Pivots of Maneuver,

DTIC Science & Technology

1991-09-05

Offensive from the Second World War , and Douglas MacArthur’s Inchon/Pusan Breakout operations will be examined to aid in the validation of the...different services together ;n a cohesive plan. Significant technological improvenentIS eare m a de du r IrI the Fi rst Worl d War , however i t was...AD-A240 322 ) Operational Implications of Pivots of Maneuver A Monograph by Major Paul C. Jussel Armor DTICS ~FIECTE D SEP 1 21991 D School of

Next-Generation Maneuvering System with Control-Moment Gyroscopes for Extravehicular Activities Near Low-Gravity Objects

NASA Technical Reports Server (NTRS)

Carpenter, Michele; Jackson, Kimberly; Cohanim, Babak; Duda, Kevin R.; Rize, Jared; Dopart, Celena; Hoffman, Jeffrey; Curiel, Pedro; Studak, Joseph; Ponica, Dina;

Pelvic floor muscle training in women with stress urinary incontinence causes hypertrophy of the urethral sphincters and reduces bladder neck mobility during coughing.

PubMed

McLean, Linda; Varette, Kevin; Gentilcore-Saulnier, Evelyne; Harvey, Marie-Andree; Baker, Kevin; Sauerbrei, Eric

2013-11-01

The purpose of this study was to determine the effect of a 12-week pelvic floor muscle (PFM) training program on urethral morphology and mobility in women with stress urinary incontinence (SUI). Forty women with SUI were randomly assigned to one of two groups: the treatment group received 12 weekly physiotherapy sessions during which they learned how to properly contract their pelvic floor muscles (PFMs) and a home exercise program was prescribed, reviewed, and progressed; the control group received no treatment. Before and after the 12-week study period, ultrasound imaging was used to evaluate bladder neck position and mobility during coughing and Valsalva maneuver in supine and in standing, as well as urethral morphology. Secondary outcome measures included a 3-day bladder diary, 30-min pad test, the Incontinence Impact Questionnaire (IIQ-7) and the Urogenital Distress Inventory (UDI-6). The women in the treatment group demonstrated reduced bladder neck mobility during coughing and increased cross-sectional area of their urethra after as compared to before the training. These changes were not evident in the control group. No differences in the resting position of the bladder neck or in bladder neck excursion during Valsalva maneuver were noted in either group. Concomitantly the women in the treatment group demonstrated significant improvements in the 3-day bladder diary and IIQ-7 after the PFM training and improved significantly more than the control group. Physiotherapist-supervised PFM training reduces bladder neck motion during coughing, and results in hypertrophy of the urethral sphincter in women who present with SUI. © 2013 Wiley Periodicals, Inc.

Ear pain and its treatment in hypobaric chamber training in the Japan Air Self-Defense Force.

PubMed

Ohrui, Nobuhiro; Takeuchi, Akihiko; Tong, Andrew; Iwata, Masashi

2008-06-01

We have documented that ear pain is the most prevalent physiologic incident during hypobaric chamber training in the Japan Air Self-Defense Force. Ear pain may increase also in flight in the future because it is closely related to allergic rhinitis. Therefore, it is very important to know the characteristic of ear pain and the efficacy of its treatment. The incidence of ear pain was calculated in each training profile from 1990 to 1998. Type III chamber flight records were further analyzed for the characteristics of ear pain: relationship with a trainee occupational category, time of occurrence of ear pain, and efficacy of treatment. Of 17,935 exposures, 740 trainees (4.1%) had ear pain. Of 7,047 trainees, 429 (6.1%) complained of ear pain especially in Type III, totaling 625 times. Fighter pilots and cargo pilots complained of ear pain one twelfth and one third the number of times, respectively, compared with passengers. Of the 625 episodes, 616 (98.6%) occurred during descent. Three kinds of treatment were administered until the pain was relieved in the following order: Valsalva maneuver, Politzer bag, and decompression. The efficacy rates were 35.8, 92.3, and 83.9%, respectively. Only 5 trainees (0.07%) could not complete training due to ear pain despite treatment. The combination treatment of Valsalva maneuver, Politzer bag, and decompression is very effective for relieving ear pain encountered during hypobaric chamber training. A health specialist needs to understand ear pain and its treatment in hypobaric environment such as aircraft.

Transcranial doppler ultrasonography should it be the first choice for persistent foramen ovale screening?

PubMed Central

2014-01-01

Background Persistent foramen ovale (PFO) is considered a cause of cryptogenic stroke and a risk factor for neurological events in young patients. The reference standard for identifying a PFO is contrast-enhanced transesophageal echocardiography (TEE). The goal of this study was to evaluate the feasibility of transcranial color Doppler (TCD) and its diagnostic sensitivity compared with TEE. Methods We investigated 420 patients admitted to our department with cryptogenic stroke, transient ischemic attacks or other neurological symptoms. All patients underwent TCD and TEE evaluation. TCD and TEE examinations were performed according to a standardized procedure: air-mixed saline was injected into the right antecubital vein three times, while the Doppler signal was recorded during the Valsalva maneuver. During TCD the passage of contrast into the right-middle cerebral artery was recorded 25 seconds following the Valsalva maneuver. Results We detected a right-to-left shunt in 220 patients (52.3%) and no-shunts in 159 patients (37.9%) with both TCD and TEE. In 20 (4.8%) patients TEE did not reveal contrast passage which was then detected by TCD. In 21 (5.0%) patients only TEE revealed a PFO. The feasibility of both methods was 100%. TCD had a sensitivity of 95% and a specificity of 92% in the diagnosis of PFO. Conclusions TCD has a relatively good sensitivity and specificity. TCD and TEE are complementary diagnostic tests for PFO, but TCD should be recommended as the first choice for screening because of its simplicity, non-invasive character, low cost and high feasibility. PMID:24884981

Pelvic floor muscle biometry and pelvic organ mobility in East Asian and Caucasian nulliparae.

PubMed

Cheung, R Y K; Shek, K L; Chan, S S C; Chung, T K H; Dietz, H P

2015-05-01

To compare the differences in levator ani muscle biometry and hiatal dimensions between pregnant nulliparous Caucasian and East Asian women. Offline analysis of three/four-dimensional ultrasound volume data obtained from two groups of pregnant nulliparous women, Caucasian and East Asian, was performed. Volume acquisition was performed in the late third trimester using the same method in both groups, in the context of two prospective observational studies with identical entry criteria. Pelvic organ descent and levator hiatal dimensions were assessed using the volumes acquired on Valsalva maneuver, and pubovisceral muscle thickness was measured from the volumes obtained on pelvic floor muscle contraction (PFMC). Datasets of 200 East Asian and 168 Caucasian women were analyzed. Compared with Caucasian women, East Asian women had a significantly lower body mass index. All indices of pelvic organ descent were significantly higher in the Caucasian group than in the East Asian group. The difference, expressed as a percentage, in levator hiatal area on both Valsalva maneuver and PFMC was markedly greater in Caucasian (32% vs. 19%; P < 0.001) than in East Asian (24% vs. 20%; P = 0.01) women. After controlling for potential confounders using multivariate regression analysis, racial origin remained the only significant factor associated with differences in pelvic organ descent and hiatal dimensions. The thickness and area of pubovisceral muscle were significantly higher in the East Asian group. Pregnant women of East Asian racial origin have a thicker pubovisceral muscle, smaller hiatus and less mobility of pelvic organs than do pregnant Caucasian women. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Pelvic Floor Muscle Training in Women With Stress Urinary Incontinence Causes Hypertrophy of the Urethral Sphincters and Reduces Bladder Neck Mobility During Coughing

PubMed Central

McLean, Linda; Varette, Kevin; Gentilcore-Saulnier, Evelyne; Harvey, Marie-Andree; Baker, Kevin; Sauerbrei, Eric

2016-01-01

Aims The purpose of this study was to determine the effect of a 12-week pelvic floor muscle (PFM) training program on urethral morphology and mobility in women with stress urinary incontinence (SUI). Methods Forty women with SUI were randomly assigned to one of two groups: the treatment group received 12 weekly physiotherapy sessions during which they learned how to properly contract their pelvic floor muscles (PFMs) and a home exercise program was prescribed, reviewed, and progressed; the control group received no treatment. Before and after the 12-week study period, ultrasound imaging was used to evaluate bladder neck position and mobility during coughing and Valsalva maneuver in supine and in standing, as well as urethral morphology. Secondary outcome measures included a 3-day bladder diary, 30-min pad test, the Incontinence Impact Questionnaire (IIQ-7) and the Urogenital Distress Inventory (UDI-6). Results The women in the treatment group demonstrated reduced bladder neck mobility during coughing and increased cross-sectional area of their urethra after as compared to before the training. These changes were not evident in the control group. No differences in the resting position of the bladder neck or in bladder neck excursion during Valsalva maneuver were noted in either group. Concomitantly the women in the treatment group demonstrated significant improvements in the 3-day bladder diary and IIQ-7 after the PFM training and improved significantly more than the control group. Conclusion Physiotherapist-supervised PFM training reduces bladder neck motion during coughing, and results in hypertrophy of the urethral sphincter in women who present with SUI. PMID:23861324

Effects of hamstring stretching on passive muscle stiffness vary between hip flexion and knee extension maneuvers.

PubMed

Miyamoto, N; Hirata, K; Kanehisa, H

2017-01-01

The purpose of this study was to examine whether the effects of hamstring stretching on the passive stiffness of each of the long head of the biceps femoris (BFl), semitendinosus (ST), and semimembranosus (SM) vary between passive knee extension and hip flexion stretching maneuvers. In 12 male subjects, before and after five sets of 90 s static stretching, passive lengthening measurements where knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, shear modulus of each muscle was measured by ultrasound shear wave elastography. Both stretching maneuvers significantly increased maximal ROM and decreased passive torque at a given joint angle. Passive knee extension stretching maneuver significantly reduced shear modulus at a given knee joint angle in all of BFl, ST, and SM. In contrast, the stretching effect by passive hip flexion maneuver was significant only in ST and SM. The present findings indicate that the effects of hamstring stretching on individual passive muscles' stiffness vary between passive knee extension and hip flexion stretching maneuvers. In terms of reducing the muscle stiffness of BFl, stretching of the hamstring should be performed by passive knee extension rather than hip flexion. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Contingency Trajectory Design for a Lunar Orbit Insertion Maneuver Failure by the LADEE Spacecraft

NASA Technical Reports Server (NTRS)

Genova, A. L.

2014-01-01

This paper presents results from a contingency trajectory analysis performed for the Lunar Atmosphere & Dust Environment Explorer (LADEE) mission in the event of a missed lunar-orbit insertion (LOI) maneuver by the LADEE spacecraft. The effects of varying solar perturbations in the vicinity of the weak stability boundary (WSB) in the Sun-Earth system on the trajectory design are analyzed and discussed. It is shown that geocentric recovery trajectory options existed for the LADEE spacecraft, depending on the spacecraft's recovery time to perform an Earth escape-prevention maneuver after the hypothetical LOI maneuver failure and subsequent path traveled through the Sun-Earth WSB. If Earth-escape occurred, a heliocentric recovery option existed, but with reduced science capacapability for the spacecraft in an eccentric, not circular near-equatorial retrograde lunar orbit.

Conflict Resolution Performance in an Experimental Study of En Route Free Maneuvering Operations

NASA Technical Reports Server (NTRS)

Doble, Nathan A.; Barhydt, Richard; Hitt, James M., II

2005-01-01

NASA has developed a far-term air traffic management concept, termed Distributed Air/Ground Traffic Management (DAG-TM). One component of DAG-TM, En Route Free Maneuvering, allows properly trained flight crews of equipped autonomous aircraft to assume responsibility for separation from other autonomous aircraft and from Instrument Flight Rules (IFR) aircraft. Ground-based air traffic controllers continue to separate IFR traffic and issue flow management constraints to all aircraft. To examine En Route Free Maneuvering operations, a joint human-in-the-loop experiment was conducted in summer 2004 at the NASA Ames and Langley Research Centers. Test subject pilots used desktop flight simulators to resolve traffic conflicts and adhere to air traffic flow constraints issued by subject controllers. The experimental airspace integrated both autonomous and IFR aircraft at varying traffic densities. This paper presents a subset of the En Route Free Maneuvering experimental results, focusing on airborne and ground-based conflict resolution, and the effects of increased traffic levels on the ability of pilots and air traffic controllers to perform this task. The results show that, in general, increases in autonomous traffic do not significantly impact conflict resolution performance. In addition, pilot acceptability of autonomous operations remains high throughout the range of traffic densities studied. Together with previously reported findings, these results continue to support the feasibility of the En Route Free Maneuvering component of DAG-TM.

"Spaghetti maneuver": a useful tool in pediatric laparoscopy - our experience.

PubMed

Marte, Antonio; Cavaiuolo, Silvia; Pintozzi, Lucia; Prezioso, Maurizio; Nino, Fabiano; Coppola, Sandra; Borrelli, Micaela; Parmeggiani, Pio

2011-01-01

The laparoscopic "Spaghetti Maneuver" consists in holding an organ by its extremity with a grasper and rolling it up around the tool to keep the organ stable and facilitate its traction within a small space. We describe our experience with the "Spaghetti Maneuver" in some minimally invasive procedures. We successfully adopted this technique in 13 patients (5F : 8M) aged between 6 and 14 years (average age, 10) on whom we performed 7 appendectomies, 2 ureteral reimplantation and 4 cholecystectomies. In all cases, after the first steps, the appendix, the gallbladder and the ureter were rolled around the grasper and easily isolated; hemostasis was thus induced and the organ was mobilized until removal during cholecystectomy and appendectomy, and before the reimplantation in case of ureteral reimplantation. We found that this technique facilitated significantly the acts of holding, isolating and removing, when necessary, the structures involved, which remained constantly within the visual field of the operator. This allowed a very ergonomic work setting, overcoming the problem of the "blind" zone, which represents a dangerous and invisible area out of the operator's control during laparoscopy. Moreover the isolation maneuvers resulted easier and reduced operating time. We think that this technique is easy to perform and very useful, because it facilitates the dissection of these organs, by harmonizing and stabilizing the force of traction exercised.

Strong Tracking Spherical Simplex-Radial Cubature Kalman Filter for Maneuvering Target Tracking.

PubMed

Liu, Hua; Wu, Wen

2017-03-31

Conventional spherical simplex-radial cubature Kalman filter (SSRCKF) for maneuvering target tracking may decline in accuracy and even diverge when a target makes abrupt state changes. To overcome this problem, a novel algorithm named strong tracking spherical simplex-radial cubature Kalman filter (STSSRCKF) is proposed in this paper. The proposed algorithm uses the spherical simplex-radial (SSR) rule to obtain a higher accuracy than cubature Kalman filter (CKF) algorithm. Meanwhile, by introducing strong tracking filter (STF) into SSRCKF and modifying the predicted states' error covariance with a time-varying fading factor, the gain matrix is adjusted on line so that the robustness of the filter and the capability of dealing with uncertainty factors is improved. In this way, the proposed algorithm has the advantages of both STF's strong robustness and SSRCKF's high accuracy. Finally, a maneuvering target tracking problem with abrupt state changes is used to test the performance of the proposed filter. Simulation results show that the STSSRCKF algorithm can get better estimation accuracy and greater robustness for maneuvering target tracking.

Strong Tracking Spherical Simplex-Radial Cubature Kalman Filter for Maneuvering Target Tracking

PubMed Central

Liu, Hua; Wu, Wen

2017-01-01

Conventional spherical simplex-radial cubature Kalman filter (SSRCKF) for maneuvering target tracking may decline in accuracy and even diverge when a target makes abrupt state changes. To overcome this problem, a novel algorithm named strong tracking spherical simplex-radial cubature Kalman filter (STSSRCKF) is proposed in this paper. The proposed algorithm uses the spherical simplex-radial (SSR) rule to obtain a higher accuracy than cubature Kalman filter (CKF) algorithm. Meanwhile, by introducing strong tracking filter (STF) into SSRCKF and modifying the predicted states’ error covariance with a time-varying fading factor, the gain matrix is adjusted on line so that the robustness of the filter and the capability of dealing with uncertainty factors is improved. In this way, the proposed algorithm has the advantages of both STF’s strong robustness and SSRCKF’s high accuracy. Finally, a maneuvering target tracking problem with abrupt state changes is used to test the performance of the proposed filter. Simulation results show that the STSSRCKF algorithm can get better estimation accuracy and greater robustness for maneuvering target tracking. PMID:28362347

Wild 2 approach maneuver strategy for Stardust spacecraft

NASA Technical Reports Server (NTRS)

Williams, Kenneth E.

2004-01-01

14th AAS/AIAA Space Flight Mechanics Meeting Maui, Hawaii, USAStardust will return samples of dust from comet Wild 2 to be collected during an encounter in January 2004. Approach to Wild 2 will be performed with a number of trajectory correction maneuvers following a period of solar conjunction ending in early October 2003.

Astronaut Bruce McCandless tests astronaut maneuvering unit

NASA Image and Video Library

1973-08-16

S72-30704 (1972) --- Astronaut Bruce McCandless II, backup pilot for Skylab 2, tests the balance and control of an astronaut maneuvering unit (AMU) test model at Martin Marietta Corporation's Denver division. The jet-powered backpack can fly for 30 minutes and can be worn over normal clothing or spacesuit. Photo credit: NASA

Skill Development for Maneuvering on the Information Highway.

ERIC Educational Resources Information Center

Mosley, Barbra; Edwards, Gloria

To help students learn to navigate the information superhighway, a 2-hour pilot program with 10 hours of guided access time was developed to test a method for teaching the basics of maneuvering the superhighway and extracting information once located. This pilot was designed as a two-part instructional session. The first instructional session…

State-dependent compound inhibition of Nav1.2 sodium channels using the FLIPR Vm dye: on-target and off-target effects of diverse pharmacological agents.

PubMed

Benjamin, Elfrida R; Pruthi, Farhana; Olanrewaju, Shakira; Ilyin, Victor I; Crumley, Gregg; Kutlina, Elena; Valenzano, Kenneth J; Woodward, Richard M

2006-02-01

Voltage-gated sodium channels (NaChs) are relevant targets for pain, epilepsy, and a variety of neurological and cardiac disorders. Traditionally, it has been difficult to develop structure-activity relationships for NaCh inhibitors due to rapid channel kinetics and state-dependent compound interactions. Membrane potential (Vm) dyes in conjunction with a high-throughput fluorescence imaging plate reader (FLIPR) offer a satisfactory 1st-tier solution. Thus, the authors have developed a FLIPR Vm assay of rat Nav1.2 NaCh. Channels were opened by addition of veratridine, and Vm dye responses were measured. The IC50 values from various structural classes of compounds were compared to the resting state binding constant (Kr)and inactivated state binding constant (Ki)obtained using patch-clamp electrophysiology (EP). The FLIPR values correlated with Ki but not Kr. FLIPRIC50 values fell within 0.1-to 1.5-fold of EP Ki values, indicating that the assay generally reports use-dependent inhibition rather than resting state block. The Library of Pharmacologically Active Compounds (LOPAC, Sigma) was screened. Confirmed hits arose from diverse classes such as dopamine receptor antagonists, serotonin transport inhibitors, and kinase inhibitors. These data suggest that NaCh inhibition is inherent in a diverse set of biologically active molecules and may warrant counterscreening NaChs to avoid unwanted secondary pharmacology.

Investigating the relationship between persistent reflux flow on the first postoperative day and recurrent varicocele in varicocelectomy patients.

PubMed

Cil, Ahmet Said; Bozkurt, Murat; Kara Bozkurt, Duygu; Gok, Mustafa

2015-01-01

The aim of this study was to investigate the presence of persistent reflux flow on the first postoperative day using color Doppler sonography (CDS) in patients who had undergone sub-inguinal varicocelectomy, and to research the relationship between persistent reflux flow and recurrent varicocele. A total of 54 patients were included in the study. Ages of the patients were between 21 and 38 years (mean 27.3 ± 7.6). All patients were evaluated four times with CDS: preoperatively, first postoperative day, 3 months postoperative, and finally 6 months after the operation. Preoperative venous diameters were measured between 3 and 5.5 mm; mean vein diameters were 3.8 ± 0.7 mm for the left side and 3.4 ± 0.4 mm for the right side. Mean duration of reflux was 3.5 ± 0.3 seconds on the left side and 2.9 ± 0.7 seconds on the right side. First postoperative day persistent Valsalva-induced reflux flow was seen in 10 patients (18%). Mean venous diameter was measured 1.8 ± 0.9 mm. Three months after the operation, Valsalva-induced reflux flow was seen in two patients (3%) in whom reflux was not seen on the first postoperative day. After 6 months, venous diameters larger than 2 mm at rest and the occurrence of reflux during the Valsalva maneuver were considered to be a recurrence. Six months after the operation, 12 patients had recurrent varicocele. Detecting persistent reflux with CDS on the first postoperative day was found to be 85% sensitive and 100% specific for showing recurrence. Valsalva-induced persistent reflux flow investigated with CDS on the first postoperative day can be used to show success of the surgery and is also an indicator of recurrence in varicocelectomy patients.

Variable structure control of spacecraft reorientation maneuvers

NASA Technical Reports Server (NTRS)

Sira-Ramirez, H.; Dwyer, T. A. W., III

1986-01-01

A Variable Structure Control (VSC) approach is presented for multi-axial spacecraft reorientation maneuvers. A nonlinear sliding surface is proposed which results in an asymptotically stable, ideal linear sliding motion of Cayley-Rodriques attitude parameters. By imposing a desired equivalent dynamics on the attitude parameters, the approach is devoid of optimal control considerations. The single axis case provides a design scheme for the multiple axes design problem. Illustrative examples are presented.

EOS Terra Terra Constellation Exit/Future Maneuver Plans Update

NASA Technical Reports Server (NTRS)

Mantziaras, Dimitrios

2016-01-01

This EOS Terra Constellation Exit/Future Maneuver Plans Update presentation will discuss brief history of Terra EOM work; lifetime fuel estimates; baseline vs. proposed plan origin; resultant exit orbit; baseline vs. proposed exit plan; long term orbit altitude; revised lifetime proposal and fallback options.

76 FR 41045 - Special Conditions; Gulfstream Aerospace LP (GALP) Model G250 Airplane, Design Roll-Maneuver...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-13

... with electronic flight controls as they relate to design roll-maneuver requirements. The applicable... load condition at design maneuvering speed V A , in which the cockpit roll control is returned to... neutral position. 3. At design cruising speed V C , the cockpit roll control must be moved suddenly and...

Early Mission Maneuver Operations for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

NASA Technical Reports Server (NTRS)

Roberts, Craig; Case, Sara; Reagoso, John; Webster, Cassandra

2015-01-01

The Deep Space Climate Observatory mission launched on February 11, 2015, and inserted onto a transfer trajectory toward a Lissajous orbit around the Sun-Earth L1 libration point. This paper presents an overview of the baseline transfer orbit and early mission maneuver operations leading up to the start of nominal science orbit operations. In particular, the analysis and performance of the spacecraft insertion, mid-course correction maneuvers, and the deep-space Lissajous orbit insertion maneuvers are discussed, com-paring the baseline orbit with actual mission results and highlighting mission and operations constraints..

Time-History Data of Maneuvers Performed by a Republic F84G Airplane During Squadron Operational Training

NASA Technical Reports Server (NTRS)

Hamer, Harold A.; Mayo, Alton P.

1953-01-01

Preliminary results of one phase of a control-motion study program involving several jet fighter-type airplanes are presented in time-history form and are summarized as maximum measured quantities plotted against indicated airspeed. The results pertain to approximately 1,000 maneuvers performed by a Republic F-84G jet-fighter airplane during squadron operational training. The data include most tactical maneuvers of which the F-84G airplane is capable. Maneuvers were performed at pressure altitudes of 0 to 30,000 feet with indicated airspeeds ranging from the stalling speed to approximately 515 knots.

Control of the maneuvering SCOLE structure

NASA Technical Reports Server (NTRS)

Lim, S.; Meirovitch, L.

1992-01-01

This paper is concerned with the vibration control of the SCOLE structure while it undergoes a slewing maneuver. The control law is designed according to the linear quadratic regulator theory. In view of saturation limits on the actuators, the actual implementation is modified so as to observe these limits, resulting in suboptimal control. State estimation is carried out by means of a Kalman filter. The control and state estimation are carried out in discrete time. Numerical simulations for several cases of interest are presented.

Single step optimization of manipulator maneuvers with variable structure control

NASA Technical Reports Server (NTRS)

Chen, N.; Dwyer, T. A. W., III

1987-01-01

One step ahead optimization has been recently proposed for spacecraft attitude maneuvers as well as for robot manipulator maneuvers. Such a technique yields a discrete time control algorithm implementable as a sequence of state-dependent, quadratic programming problems for acceleration optimization. Its sensitivity to model accuracy, for the required inversion of the system dynamics, is shown in this paper to be alleviated by a fast variable structure control correction, acting between the sampling intervals of the slow one step ahead discrete time acceleration command generation algorithm. The slow and fast looping concept chosen follows that recently proposed for optimal aiming strategies with variable structure control. Accelerations required by the VSC correction are reserved during the slow one step ahead command generation so that the ability to overshoot the sliding surface is guaranteed.

Maneuvering Melt Ponds

NASA Image and Video Library

2017-12-08

On July 10, 2011, Don Perovich, of Cold Regions Research and Engineering Laboratory, maneuvered through melt ponds collecting optical data along the way to get a sense of the amount of sunlight reflected from sea ice and melt ponds in the Chukchi Sea. The ICESCAPE mission, or "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is a NASA shipborne investigation to study how changing conditions in the Arctic affect the ocean's chemistry and ecosystems. The bulk of the research took place in the Beaufort and Chukchi seas in summer 2010 and 2011. Credit: NASA/Kathryn Hansen NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Antioxidant and inflammatory biomarkers for the identification of prodromal Parkinson's disease.

PubMed

Campolo, Jonica; De Maria, Renata; Cozzi, Lorena; Parolini, Marina; Bernardi, Stefano; Proserpio, Paola; Nobili, Lino; Gelosa, Giorgio; Piccolo, Immacolata; Agostoni, Elio C; Trivella, Maria G; Marraccini, Paolo

2016-11-15

We explored the role of oxidative stress and inflammatory molecules as potential Parkinson (PD) biomarkers and correlated biological with non-motor abnormalities (olfactory impairment and dysautonomia), in patients with idiopathic REM behavior disorder (iRBD) (prodromal PD) and established PD. We recruited 11 iRBD and 15 patients with idiopathic PD (Hohen&Yahr 1-3, on L-DOPA and dopamine agonists combination therapy) and 12 age- and sex-matched controls (CTRL). We measured total olfactory score (TOS), autonomic function [deep breathing (DB), lying to standing (LS) and Valsalva manoeuvre (VM) ratios], blood reduced glutathione (Br-GSH), oxidative stress and inflammatory markers (neopterin). Anosmia was similarly prevalent in iRBD (36%) and PD (33%) patients, but absent in CTRL. Orthostatic hypotension was more common among iRBD (73%) and PD (60%) than in CTRL (25%). By univariable ordinal logistic regression, TOS, Br-GSH, LS and VM ratio worsened from CTRL to iRBD and PD groups. Only reduced Br-GSH levels (p=0.037, OR=0.994; 95%CI 0.988-1.000) were independently associated to PD. TOS correlated with Br-GSH (R=0.34, p=0.037), VM ratio (R=0.43, p=0.015), and neopterin (rho=0.39, p=0.016). Reduced systemic antioxidant capacity is found in prodromal and overt PD and may represent, in association with olfactory loss and cardiovascular dysautonomia, a useful biomarker for an integrative, early diagnosis of PD. Copyright © 2016 Elsevier B.V. All rights reserved.

Techniques to improve maneuver stability characteristics of a nonlinear wide-body transport airplane in cruise flight

NASA Technical Reports Server (NTRS)

Grantham, William D.; Person, Lee H., Jr.; Bailey, Melvin L.; Tingas, Stephen A.

1994-01-01

The maneuver control stability characteristics of an aircraft are a flying qualities parameter of critical importance, to ensure structural protection as well as adequate predictability to the pilot. Currently, however, maneuver stability characteristics are not uniquely addressed in the Federal Aviation Regulations (FAR) Part 25, for transport aircraft. In past transport category certification programs, the Federal Aviation Administration (FAA) has used a combination of requirements (longitudinal control, vibration and buffeting, high-speed characteristics, and out-of-trim characteristics) to ensure safe and controllable maneuver stability characteristics over a range of flight conditions and airplane configurations. Controversies exist regarding each of these regulations, however, and considerable expenditures in terms of design studies and testing time have resulted from the requirements. It is also recognized that additional engineering guidance is needed for identifying acceptable nonlinear maneuver stability characteristics, particularly as they relate to relaxed stability, highly augmented transport configurations. The current trend in large aircraft design is toward relaxed, or even negative, static margins for improved fuel efficiency. The advanced flight control systems developed for these aircraft, in many instances, have rendered current aforementioned maneuver stability criteria either too stringent or of little practical use. Current design requirements do not account for these advanced designs. The objective was to evaluate a broad spectrum of linear and nonlinear longitudinal stability characteristics to generate data for defining satisfactory and unacceptable maneuver characteristics, as defined by pilot opinion. Primary emphasis was placed on two techniques of varying column force per normal acceleration. This study was a joint venture with four pilots participating; one from NASA, one from the FAA, and two from industry.

Exploration of the Trade Space Between Unmanned Aircraft Systems Descent Maneuver Performance and Sense-and-Avoid System Performance Requirements

NASA Technical Reports Server (NTRS)

Jack, Devin P.; Hoffler, Keith D.; Johnson, Sally C.

2014-01-01

A need exists to safely integrate Unmanned Aircraft Systems (UAS) into the United States' National Airspace System. Replacing manned aircraft's see-and-avoid capability in the absence of an onboard pilot is one of the key challenges associated with safe integration. Sense-and-avoid (SAA) systems will have to achieve yet-to-be-determined required separation distances for a wide range of encounters. They will also need to account for the maneuver performance of the UAS they are paired with. The work described in this paper is aimed at developing an understanding of the trade space between UAS maneuver performance and SAA system performance requirements, focusing on a descent avoidance maneuver. An assessment of current manned and unmanned aircraft performance was used to establish potential UAS performance test matrix bounds. Then, near-term UAS integration work was used to narrow down the scope. A simulator was developed with sufficient fidelity to assess SAA system performance requirements. The simulator generates closest-point-of-approach (CPA) data from the wide range of UAS performance models maneuvering against a single intruder with various encounter geometries. Initial attempts to model the results made it clear that developing maneuver performance groups is required. Discussion of the performance groups developed and how to know in which group an aircraft belongs for a given flight condition and encounter is included. The groups are airplane, flight condition, and encounter specific, rather than airplane-only specific. Results and methodology for developing UAS maneuver performance requirements are presented for a descent avoidance maneuver. Results for the descent maneuver indicate that a minimum specific excess power magnitude can assure a minimum CPA for a given time-to-go prediction. However, smaller amounts of specific excess power may achieve or exceed the same CPA if the UAS has sufficient speed to trade for altitude. The results of this study will

Calibrating/testing meters in hot water test bench VM7

NASA Astrophysics Data System (ADS)

Kling, E.; Stolt, K.; Lau, P.; Mattiasson, K.

A Hot Water Test Bench, VM7, has been developed and constructed for the calibration and testing of volume and flowmeters, in a project at the National Volume Measurement Laboratory at the Swedish National Testing and Research Institute. The intended area of use includes use as a reference at audit measurements, e.g. for accredited laboratories, calibration of meters for the industry and for the testing of hot water meters. The objective of the project, which was initiated in 1989, was to design equipment with stable flow and with a minimal temperature drop even at very low flow rates. The principle of the design is a closed system with two pressure tanks at different pressures. The water is led from the high pressure tank through the test object and the volume standard, in the form of master meters or a piston prover alternatively, to the low pressure tank. Calibrations/tests are made comparing the indication of the test object to that of master meters covering the current flow rate. These are, in the same test cycle, calibrated to the piston prover. Alternatively, the test object can be calibrated directly to the piston prover.

Existence of a novel enzyme, pyrroloquinoline quinone-dependent polyvinyl alcohol dehydrogenase, in a bacterial symbiont, Pseudomonas sp. strain VM15C.

PubMed Central

Shimao, M; Ninomiya, K; Kuno, O; Kato, N; Sakazawa, C

1986-01-01

A novel enzyme, pyrroloquinoline quinone (PQQ)-dependent polyvinyl alcohol (PVA) dehydrogenase, was found in and partially purified from the membrane fraction of a PVA-degrading symbiont, Pseudomonas sp. strain VM15C. The enzyme required PQQ for PVA dehydrogenation with phenazine methosulfate, phenazine ethosulfate, and 2,6-dichlorophenolindophenol as electron acceptors and did not show PVA oxidase activity leading to H2O2 formation. The enzyme was active toward low-molecular-weight secondary alcohols rather than primary alcohols. A membrane-bound PVA oxidase was also present in cells of VM15C. Although the purified oxidase showed a substrate specificity similar to that of PQQ-dependent PVA dehydrogenase and about threefold-higher PVA-dehydrogenating activity with phenazine methosulfate or phenazine ethosulfate than PVA oxidase activity with H2O2 formation, it was shown that the enzyme does not contain PQQ as the coenzyme, and PQQ did not affect its activity. Incubation of the membrane fraction of cells with PVA caused a reduction in the cytochrome(s) of the fraction. Images PMID:3513704

Effect of hinge-moment parameters on elevator stick forces in rapid maneuvers

NASA Technical Reports Server (NTRS)

Jones, R. T.; Greenberg, H.

1976-01-01

The importance of the stick force per unit normal acceleration as a criterion of longitudinal stability and the critical dependence of this gradient on elevator hinge moment parameters are investigated with special reference to transient effects for maneuvers of short duration. The analysis shows that different combinations of elevator parameters, which give the same stick force per unit acceleration in turns, give widely different force variations during the entries into and recoveries from steady turns and during maneuvers of short duration such as abrupt pull-ups. The stick force per unit acceleration is greater for abrupt than for gradual control movements.

An exploratory investigation of the STOL landing maneuver

NASA Technical Reports Server (NTRS)

Whyte, P. H.

1979-01-01

The parameters influencing the STOL landing are identified and their effect on the ease and quality of the flare maneuver is discussed. Data from actual landings, supported by pilot commentary and pilot opinion rating, are analyzed. Hypotheses concerning the prediction of STOL handling qualities in the flare are proposed, and suggestions for future research are presented.

The importance of a normal breathing pattern for an effective abdominal-hollowing maneuver in healthy people: an experimental study.

PubMed

Ha, Sung-min; Kwon, Oh-yun; Kim, Su-jung; Choung, Sung-dae

2014-02-01

A normal breathing pattern while performing the abdominal-hollowing (AH) maneuver or spinal-stabilization exercise is essential for the success of rehabilitation programs and exercises. In previous studies, subjects were given standardized instructions to control the influence of respiration during the AH maneuver. However, the effect of breathing pattern on abdominal-muscle thickness during the AH maneuver has not been investigated. To compare abdominal-muscle thickness in subjects performing the AH maneuver under normal and abnormal breathing-pattern conditions and to investigate the effect of breathing pattern on the preferential contraction ratio (PCR) of the transverse abdominis. Comparative, repeated-measures experimental study. University research laboratory. 16 healthy subjects (8 male, 8 female) from a university population. A real-time ultrasound scanner was used to measure abdominal-muscle thickness during normal and abnormal breathing patterns. A paired t test was used to assess the effect of breathing pattern on abdominal-muscle thickness and PCR. Muscle thickness in the transverse abdominis and internal oblique muscles was significantly greater under the normal breathing pattern than under the abnormal pattern (P < .05). The PCR of the transverse abdominis was significantly higher under the normal breathing pattern compared with the abnormal pattern (P < .05). The results indicate that a normal breathing pattern is essential for performance of an effective AH maneuver. Thus, clinicians should ensure that patients adopt a normal breathing pattern before performing the AH maneuver and monitor transverse abdominis activation during the maneuver.

[Hemodynamic variability caused by pressure-volume plotting and alveolar recruitment maneuvers in patients with adult respiratory distress syndrome].

PubMed

Pestaña, D; Royo, C; Hernández-Gancedo, C; Martínez-Casanova, E; Criado, A

2008-01-01

The plotting of pressure-volume curves and the performance of alveolar recruitment maneuvers are common practices in the care of patients with adult respiratory distress syndrome (ARDS), even though potentially harmful hemodynamic effects are associated with sustaining a high intrathoracic pressure. Our aim was to analyze hemodynamic and ventilatory changes related to these 2 maneuvers and to assess the short-term effectiveness of recruitment. The patients had ARDS and were being monitored with a catheter connected to a PiCCO system. All measurements were taken in sinus rhythm and with adequate vascular filling. Values recorded during plotting of the quasistatic pressure-volume curve and the recruitment maneuver (sustained airway pressure of 40 cm H2O) were the cardiac index, mean arterial pressure, heart rate, systolic volume index, and oxygen saturation (SpO2). Blood gas measurements were recorded before the maneuvers and 15 minutes afterwards. All parameters decreased significantly in the 14 patients studied. The mean (SD) maximum decreases, from which all patients recovered within 2 minutes, were as follows: cardiac index, 26% (16%); mean arterial pressure, 6% (6%); heart rate, 4% (5%), systolic volume index, 21% (15%); and SpO2, 3% (3%). Significant increases in PaO2 (7% [6%]) and the ratio of PaO2 to the fraction of inspired oxygen were recorded after the recruitment maneuver (P=.016 and P=.014, respectively), but the changes were not clinically significant. The hemodynamic disturbances associated with the alveolar recruitment maneuver based on sustaining a high end-expiratory pressure and the minor improvement in oxygenation achieved as a result suggest that the routine use of that maneuver in ARDS patients is of questionable value.

A Proposed Maneuver to Guide Transseptal Puncture Using Real-Time Three-Dimensional Transesophageal Echocardiography: Pilot Study.

PubMed