Flight test of navigation and guidance sensor errors measured on STOL approaches

Navigation and guidance sensor error characteristics were measured during STOL approach-flight investigations. Data from some of the state sensors of a digital avionics system were compared to corresponding outputs from an inertial navigation system. These sensors include the vertical gyro, compass, and accelerometers. Barometric altimeter data were compared to altitude measured by a tracking radar. Data were recorded with the Augmentor Wing Jet STOL Research Aircraft parked and in flight

A flight investigation of a 4D area navigation system concept for STOL aircraft in the terminal area

A digital avionics system referred to as STOLAND was test flown in the NASA CV-340 aircraft to obtain performance data for time controlled guidance in the manual flight director mode. The advanced system components installed in the cockpit included an electronic attitude director indicator and an electronic multifunction display. Navigation guidance and control computations were performed on a digital computer. A detailed 4D area navigation systems description is given. The pilot/system interface and systems operation and performance are also described. Approach flightpaths were flown which included a 180 deg turn and a 1-min, 5 deg straight-in approach to 30 m altitude, at which point go-around was initiated. Results are presented for 19 approaches

User's manual: Subsonic/supersonic advanced panel pilot code

Sufficient instructions for running the subsonic/supersonic advanced panel pilot code were developed. This software was developed as a vehicle for numerical experimentation and it should not be construed to represent a finished production program. The pilot code is based on a higher order panel method using linearly varying source and quadratically varying doublet distributions for computing both linearized supersonic and subsonic flow over arbitrary wings and bodies. This user's manual contains complete input and output descriptions. A brief description of the method is given as well as practical instructions for proper configurations modeling. Computed results are also included to demonstrate some of the capabilities of the pilot code. The computer program is written in FORTRAN IV for the SCOPE 3.4.4 operations system of the Ames CDC 7600 computer. The program uses overlay structure and thirteen disk files, and it requires approximately 132000 (Octal) central memory words

A method for determining landing runway length for a STOL aircraft

Based on data obtained from flight tests of the augmentor wing jet STOL research aircraft, a method is proposed for determining the length of the landing runway for powered-lift STOL aircraft. The suggested method determines runway landing length by summing three segments: the touchdown-dispersion distance, the transition distance from touchdown to application of brakes, and the stopping distance after brakes are applied. It is shown how the landing field length can be reduced either through improved autoland system design or by providing the pilot with appropriate information to allow him to identify a "low probability" long or short landing and to execute a go-around. The proposed method appears to determine a safe runway landing length for the STOL application and offers the potential for reducing runway length if great emphasis is placed on a short-runway capability. FAR Parts 25 and 121 appear conservative and suitable for the situation where no great emphasis is placed on reducing the runway length requirement

Mitochondrial Haplotypes suggest Genetic Component for Habitat Preference in Blue Crabs

Atlantic blue crabs (Callinectes sapidus) are ecologically and commercially fundamental. Life stages are punctuated with migration. Adults and juveniles live in estuaries and sounds. Larval stages develop in the coastal ocean. Juvenile and adult crabs occupy habitats from high salinities to fresh water. We determined whether maturing juvenile and adult blue crab habitat use is reflected in mitochondrial cytochrome oxidase 1 haplotypes. High salinity crabs had lower haplotype diversity (0.7260 ± .03900) compared to spawning crabs (0.9841 ± .00021) and low salinity crabs (0.94154 ± .00118). Significant pairwise differences in haplotypes were found between high salinity and spawning crabs (Nm = 0.26018, p < 0.001), and between high salinity and low salinity crabs (Nm = 0.19482, p < 0.001) indicating a lack of gene flow. Crabs from high salinity had highly significant genetic differentiation compared to spawning crabs (Fst = 0.11830, p < 0.001) and low salinity crabs (Fst = 0.09689, p < 0.001). Results support the hypothesis that genetics influence habitat selection. Crab larvae mix in the coastal ocean but occupy specific habitats upon return to sounds and estuaries. These findings have implications for the management of fisheries

Effet inhibiteur à la longues chaînes et de dérivés thiazolés sur la corrosion du laiton Amirauté.optimale des petites stations d'épuration à boues activées

Dans cette étude, des mesures électrochimiques ont été réalisées pour caractériser le comportement du laiton Amirauté dans une solution de chlorure de sodium 0,5 M en l'absence d'inhibiteur et en présence d'un mélange d'amines à longue chaîne et de dérivés thiazolés. Cette formulation est utilisée pour le traitement des eaux des circuits de refroidissement. Les courbes courant-tension stationnaires et les diagrammes d'impédance électrochimique ont été obtenus avec une electrode tournante.La première partie de cette étude présente les résultats obtenus pour deux concentrations du mélange et deux temps d'immersion préalable au potentiel de corrosion. Les essais électrochimiques montrent que l'effet inhibiteur est d'autant plus marqué que la concentration augmente. Une légère diminution de la protection de la surface du laiton Amirauté est observée avec l'augmentation du temps de maintien au potentiel de corrosion.La deuxième partie de l'étude compare les effets inhibiteurs de chacun des constituants du mélange, d'une part, pour les valeurs de concentration utilisées lors du traitement des eaux des circuits de refroidissement (0,1 mg/l de solution contenant les dérivés thiazolés et 1 mg/l de solution contenant les alkylamines) et, d'autre part, pour des valeurs de concentration comparables (5 mg/l).Pour la concentration de 0,1 mg/l l'action inhibitrice des dérivés thiazolés n'a pas été clairement mise en évidence. Ainsi, la protection contre la corrosion des circuits de refroidissement en laiton Amirauté avec le mélange est apportée principalement par les alkylamines. Celles-ci forment un film compact très protecteur à la surface de l'électrode.Pour des valeurs de concentration plus importantes, l'addition de 0,5 mg/l de dérivés thiazolés à 5 mg/l d'alkylamines améliore la protection du matériau.In this study, electrochemical measurements were carriet out to characterize the behaviour of Admiralty Brass in a 0.5 M sodium chloride solution in the absence of inhibitors and in the presence of a mixture of alkylamines and thiazol-derived products. This formulation is employed for water treatment in cooling circuits.The steady-state current voltage curves and the impedance diagrams were obtained with a rotating disc electrode in order to control the hydrodynamic conditions.The first part of this study deals with the results obtained for two concentrations of the mixture and for two immersion times at the corrosion potential. It has been shown that the inhibitive effect is more marked when the concentration increases from 10 to 50 mg/l. A slight decrease of the protection of the brass surface is observed when the immersion time increasesThe second part of this study is a comparison of the inhibitive effects of each compound of the mixture, on one hand, for concentration values used in the water treatment (0.1 mg/l of tbe solution containing the thiazol-derived products and 1 mg/l of the solution containing the alkylamines) and on the other hand, for identical concentration values (5 mg/l ). For 0.1 mg/l, no inhibitive action of thiazol-derived products could be detected. Thus, the corrosion protection of cooling circuits in Admiralty brass is attributed essentially to the alkylamines. They form a thick, protective film at the electrode surface. For higher concentration values, the addition of 0.5 mg/l of thiazol-derived products to 5 mg/l of alkylamines improves the corrosion resistance of brass

Inhibition de la corrosion d'un acier au carbone par des produits dérivés de phosphonates en association avec des sels de zinc

Dans cette étude, des mesures électrochimiques ont été utilisées pour caractériser l'efficacité inhibitrice de produits dérivés de phosphonates associés à des sels de zinc, employés pour le traitement des eaux des circuits de refroidissement. L'influence de la concentration de cette formulation ainsi que l'effet du pH du milieu ont été étudiés.Les courbes courant-tension stationnaires et les diagrammes d'impédance électrochimique ont été obtenus avec des électrodes tournantes en acier au carbone dans une solution de chlorure de sodium à 200 mg l-1. Ce milieu a été choisi car sa faible conductivité électrique est proche de celle rencontrée dans les eaux naturelles.La méthode stationnaire (relevé des courbes courant-tension) a permis de déterminer la vitesse de corrosion en l'absence et en présence de l'inhibiteur et par conséquent, le taux de protection. Ainsi, le composé présente une très bonne efficacité dès les faibles concentrations (50 mg · l-1). Entre 50 et 200 mg · l-1, l'efficacité inhibitrice augmente de 95 à 98 %. Pour la concentration de 100 mg · l-1 il est efficace dans un large domaine de pH (de 5,5 à 9). Cette efficacité apparaît légèrement supérieure à pH = 7 et à pH = 8.Les valeurs des résistances de polarisation mesurées à partir des diagrammes d'impédance confirment les résultats obtenus à partir des courbes stationnaires.En outre, l'efficacité inhibitrice du composé a été comparée à celle de produits déjà testés au Laboratoire pour des utilisations identiques. Le chlorure de zinc, le monofluorophosphate de zinc et l'association d'une amine grasse et d'acide phosphonique présentent des efficacités moindres que le mélange testé ici à base de produits dérivés de phosphonates associés aux sels de zinc.In this study, electrochemical measurements were carried out to characterize the inhibitive efficiency of the association of phosphonate-derived products with zinc salts, employed for water treatment in cooling circuits.The influence of parameters such as the concentration of the formulation and the effect of the solutions pH on the protection of the metal were studied.Steady-state current-voltage curves and electrochemical impedance diagrams have been obtained for a carbon steel rotating disc in a 200 mg · l-1 NaCl solution. The choice of this medium is based upon the following criteria :(i) its low electrical conductivity is close to that encountered in natural saline waters ;(ii) its corrosivity is fairly high ;(iii) it Is formed by an easily reproducible baseline solution.The inhibitive efficiency has been determined tram the plotting of the cathodic potentiostatic curves. It is important to note that in low conductivity media, the current-voltage curves are distorted by a non-negligible uncompensated ohmic drop (I.Re), Re being the electrolyte resistance between the working and the reference electrodes. The interpretation of these curves (i.e. corrosion rate evaluation, Tafel slopes determination) is only possible if they have been corrected according to the following relationship. Eapparent = Etrue + ReIIn this study, the electrolytic resistance value has been determined from electrochemical Impedance measurements : the high frequency limit of the impedance gives Re.The ohmic drop is then automatically compensated by the potentiostat to obtain the corrected steady-state curve.The inhibitive efficiency is evaluated by the relationship :Ei = (icorr0-icorr / icorr0) x 100in which iocorr and icorr represent the current densities without and with inhibitor, respectively.In addition to the determination of the current densities obtained from the steady-state current-voltage curves, the polarization resistance, Rp, has been measured from the impedance diagram : the low frequency limit of the impedance gives the sum Re + Rp ; Rp is equal to the slope of the steady-state current voltage curve.In this study, only the evolution of this value as a function of concentration has been examined.It has been shown from the steady-state technique that the compound presents a very good efficiency for low concentrations (50 mg · l-1). Between 50 and 200 mg · l-1, the inhibitive efficiency increases from 95 to 98 %. For 100 mg · l-1 it is effective over a wide pH range (5.5 to 9) with a better protection for pH = 7 and pH = 8.The measurements of the polarization resistance corroborate these results.In a second part, the inhibitive efficiency of the compound has been compared to different inhibitors used for similar uses and tested in the laboratory. Thus, zinc chloride, zinc fluorophosphate and the association of fatty amine and phosphonic acid present a lower efficiency than the product tested here

Preventing maternal deaths due to ectopic pregnancy

The majority of maternal deaths due to ectopic pregnancy (EP) could be avoided if the health service renders better-quality care. There are two common clinical mistakes that lead to death from EP: (i) failure to make the diagnosis, because the attending healthcare worker does not consider this option; and (ii) failure to act urgently to stop the bleeding when there are signs of hypovolaemic shock. The only reliable way to stop the bleeding in a shocked patient with a ruptured EP is to urgently perform a laparotomy and clamp the bleeding vessels. Doctors at district hospitals must learn and maintain the skills required to provide anaesthesia for and operate on patients with a ruptured EP

Spatial Structure of Stationary Nonequilibrium States in the Thermostatted Periodic Lorentz Gas

We investigate analytically and numerically the spatial structure of the non-equilibrium stationary states (NESS) of a point particle moving in a two dimensional periodic Lorentz gas (Sinai Billiard). The particle is subject to a constant external electric field E as well as a Gaussian thermostat which keeps the speed |v| constant. We show that despite the singular nature of the SRB measure its projections on the space coordinates are absolutely continuous. We further show that these projections satisfy linear response laws for small E. Some of them are computed numerically. We compare these results with those obtained from simple models in which the collisions with the obstacles are replaced by random collisions.Similarities and differences are noted.Comment: 24 pages with 9 figure

Exercises for improving quick perception grades I, II, III.

Thesis (Ed.M.)--Boston University N.B.: Page 242 is misnumbered. No content is missing from thesis