Pterodactyl: Control System Demonstrator Development for Integrated Control Design of a Mechanically Deployed Entry Vehicle

The NASA-funded Pterodactyl project is a design, test, and build capability to (i) advance the current state of the art for Deployable Entry Vehicle (DEV) guidance and control (G&C), and (ii) determine the feasibility of control system integration for various entry vehicle types including those without aeroshells. This capability is currently being used to develop control systems for one such unconventional entry vehicle, the Lifting Nano-ADEPT (LNA) vehicle. ADEPT offers the possibility of integrating control systems directly onto the mechanically deployed structure and building hardware demonstrators will help assess integration and design challenges. Control systems based on aerodynamic control surfaces, mass movement, and reaction control systems (RCS) are currently being investigated for a down-select to the most suitable control architecture for the LNA.To that effect, in this submission, we detail the efforts of the Pterodactyl project to develop a series of hardware demonstrators for the different LNA control systems. Rapid prototypes, for a set of quarter- model or eighth-model vehicle segments, will be developed for all three architectures to validate mechanical design assumptions, and hardware-in-the-loop (HIWL) control approaches. A ground test control system demonstrator will be designed and built after the trade study is complete. The industrial-grade demonstrator will be designed so that it can be incorporated into a HWIL simulation to further validate the findings of the initial trade study. The HWIL simulation will leverage the iPAS environment developed at NASA's Johnson Space Center which facilitates integration testing to support technology maturation and risk reduction, necessary elements for the hardware demonstration development detailed in this paper

Pterodactyl: Control Architectures Development for Integrated Control Design of a Mechanically Deployed Entry Vehicle

The need to return high mass payloads is driving the development of a new class of vehicles, Deployable Entry Vehicles (DEV) for which feasible and optimized control architectures have not been developed. The Pterodactyl project, seeks to advance the current state-of-the-art for entry vehicles by developing a design, test, and build capability for DEVs that can be applied to various entry vehicle configurations. This paper details the efforts on the NASA-funded Pterodactyl project to investigate multiple control techniques for the Lifting Nano-ADEPT (LNA) DEV. We design and implement multiple control architectures on the LNA and evaluate their performance in achieving varying guidance commands during entry.First we present an overview of DEVs and the Lifting Nano-ADEPT (LNA), along with the physical LNA configuration that influences the different control designs. Existing state-of-the-art for entry vehicle control is primarily propulsive as reaction control systems (RCS) are widely employed. In this work, we analyze the feasibility of using both propulsive control systems such as RCS to generate moments, and non-propulsive control systems such as aerodynamic control surfaces and internal moving mass actuations to shift the LNA center of gravity and generate moments. For these diverse control systems, we design different multi-input multi-output (MIMO) state-feedback integral controllers based on linear quadratic regulator (LQR) optimal control methods. The control variables calculated by the controllers vary, depending on the control system being utilized and the outputs to track for the controller are either the (i) bank angle or the (ii) angle of attack and sideslip angle as determined by the desired guidance trajectory. The LQR control design technique allows the relative allocation of the control variables through the choice of the weighting matrices in the cost index. Thus, it is easy to (i) specify which and how much of a control variable to use, and (ii) utilize one control design for different control architectures by simply modifying the choice of the weighting matrices.By providing a comparative analysis of multiple control systems, configurations, and performance, this paper and the Pterodactyl project as a whole will help entry vehicle system designers and control systems engineers determine suitable control architectures for integration with DEVs and other entry vehicle types

Pterodactyl: Development and Comparison of Control Architectures for a Mechanically Deployed Entry Vehicle

The Pterodactyl project, seeks to advance the current state-of-the-art for entry vehicles by developing novel guidance and control technologies for Deployable Entry Vehicles (DEVs) that can be applied to various entry vehicle configurations. This paper details the efforts on the NASA-funded Pterodactyl project to investigate and implement multiple control techniques for an asymmetric mechanical DEV. We design multiple control architectures for a Pterodactyl Baseline Vehicle (PBV) and evaluate their performance in achieving varying guidance commands during entry. The control architectures studied are (i) propulsive control systems such as reaction control systems and (ii) non-propulsive control systems such as aerodynamic control surfaces and internal moving masses. For each system, state-feedback integral controllers based on linear quadratic regulator (LQR) optimal control methods are designed to track guidance commands of either (i) bank angle or (ii) angle of attack and sideslip angle as determined by the desired guidance trajectory. All control systems are compared for a lunar return reference mission and by providing a comparative analysis of these systems, configurations, and performance, the efforts detailed in this paper and the Pterodactyl project as a whole will help entry vehicle system designers determine suitable control architectures for integration with DEVs and other entry vehicle types

The effects of malting conditions on the diastatic power of three malted Nigerian sorghum cultivars

The effects of malting conditions on the diastatic power of three malted sorghum cultivars (SK 5912, ICSV 400 and KSV 8) were investigated. The three Nigerian sorghum cultivars were steeped in 0.01M NaOH, 0.01M Ca(OH)2 and distilled water, respectively, under air-rest and continuous steeping regimes. SK 5912 steeped in Ca(OH)2 gave higher hot water and cold water extract values than when steeped in NaOH and distilled water. KSV 8 when steeped in distilled water gave peak values for cold water extract during air-rest and continuous steeping regimes. For hot water extract, KSV 8 had peak values when steeped in NaOH whereas SK 5912 gave the least values when steeped in distilled water. Cold water soluble-carbohydrate gave peak values for ICSV 400 when steeped in Ca(OH)2 and the least values were recorded in NaOH steeped grains. The diastatic power of the three sorghum cultivars improved with increase in germination time except for ICSV 400-steeped in Ca(OH)2 and KSV 8 steeped in distilled water which showed decrease in activity on the 4th day in continuous steeping regime. The results show that steeping in dilute alkali solutions gave higher values than distilled water while air-rested steeping regime gave better values than continuous steeping regime. The results from this study suggest that increase in germination time enhanced the diastatic power of the malted grain.Keywords: Sorghum varieties, Malting, Diastatic power, Cold water extract, Hot water extrac

Effect of Moisture Content and Grain Variety on Frictional Properties and Specific Heat Capacity of Acha (Fonio) Grains

There are many varieties of acha, but the most prominent two are white acha (Digitaria exilis) and brown acha (Digitaria iburua). This study was undertaken to determine the static coefficient of friction, kinetic coefficient of friction and specific heat of the grains as influenced by moisture content. The moisture levels considered were 5, 11, 23 and 28% db for the white variety and 5, 9, 21 and 30% db. The study revealed that increase in moisture content resulted to increase in the value of the properties considered for both varieties, with the white acha showing the highest values. Static coefficient of friction increased linearly with moisture content and had maximum values of 0.49 - 0.62 for the brown variety and 0.52-0.66 for the white variety all on steel sheet, while the minimum values for both varieties were on glass surface. Kinetic coefficient of friction increased linearly with moisture content and the highest value was obtained on hessian bag material (0.62-0.66) with the least being on steel sheet (0.58-0.64) for the two acha grain varieties. The study further revealed that, specific heat capacity of acha grains increased with increase in moisture content from 2.93 – 11.29 kJ/kgK (5 – 28% db) for the white variety and from 2.33 – 13.88 kJ/kgK (5 – 30% db) for brown variety. This study concludes that variety and changes in moisture content significantly affected the determined properties of acha

Numerical Simulation for the Transmission Dynamics of Avian Influenza

This paper presents numerical simulations for the transmission dynamics of avian influenza using the model formulated and analysed by Kimbir etal (2014). It is proved that the disease free equilibrium state is locally asymptotically stable whenever the reproduction number is less than unity. The implication is that if the reproduction number is less than unity, the infection is controlled or eradicated and the disease persists otherwise. The numerical simulations are consistent with the local stability of the disease-free states. The simulations further reveals that the infection transmission rate constitutes an essential parameter for an epidemic to occur, thus efforts should be geared at bringing the infection transmission to the lowest level in order to ensure eradication. It was also shown from the study that increasing culling of infected birds, will reduce the disease progression within the birds’ population thereby, reducing the transmission of avian influenza. Effective isolation of infected individuals without culling is vital to eradicating the disease transmission, but a combined effective use of culling of infected birds and isolation of infected humans is a strong control measure against pandemics. Key words: Avian influenza, Mathematical model, Basic reproduction number, Numerical simulation

A Model Analysis for the Transmission Dynamics of Avian Influenza

This paper examines the transmission dynamics of avian influenza. A nonlinear mathematical model for the problem is formulated and analysed. For the prevalence of the disease and the ease of analysis, we considered the model in proportions of susceptible, infectious, isolated and recovered compartments. The basic reproduction number was computed and used to prove the stability of the disease free equilibrium states. It is proved that the basic reproduction number is a decreasing function of the culling rate of infected birds. It is further proved that the disease free equilibrium state is locally asymptotically stable whenever the basic reproduction number is less than unity. Key words: Avian influenza, Mathematical model, Basic reproduction number. Disease free equilibriu

Women empowerment and participation in economic activities: Indispensable tools for self-reliance and development of Nigerian society

The objective of the study was to examine women empowerment and participation in economic activities as tools for self-reliance and development of the Nigerian society. Research questions and hypothesis were used to guide the study. Structured questionnaire was used as the major instrument for data collection. Copies of questionnaires were administered to 402 women randomly selected from 6 out of the 21 local government Areas of Anambra State. 351 copies of questionnaire recovered were analyzed using mean to answer the research questions and t-test statistic to draw inferences about the hypothesis. The results showed that: farming, trading, craft, food processing, hair dressing, poultry and the likes were the major economic activities performed by women in Anambra state. Personal savings, family assistance, philanthropist's assistance, loans and credits, cooperative society assistance, group contributions, were the sources of fund available to the women for their economic activities. Education and health promotion, food supply and distribution, were some of the services rendered by the women that bring about societal development. Inability of government to provide support, corruption on the part of implementers, family burden, cultural restrictions, husband influence, illiteracy were the obstacles women encounter in carrying out their economic activities. Provision of sustainable land tenure system, provision of soft loans and credits, training programmes, funding, establishment of cooperative societies, were some of the strategies proffered to enhance women participation in economic activities

Small-for-gestational Age, Ponderal Index and Neonatal Polycythaemia: A Study of Their Association with Maternal Hypertension Among Nigerian Women

Background/Objective: To examine the influence of maternal hypertension on rate of delivery of small-for-gestation age (SGA) infants, incidence of neonatal polycythaemia and mean ponderal indices of the resultant newborn infants. Methods: From the birth weights and lengths, the ponderal indices of SGA infants born to mothers with chronic hypertension were compared with those of their counterparts born to mothers with pregnancy-induced hypertension. In addition, the spun venous haematocrit values of 265 infants born to mothers whose pregnancies were complicated by hypertension were compared with those of 804 infants born to control mothers. Results: The rates of delivery of SGA infants were 82.0 and 54.7 per 1000 live births among hypertensive and normotensive mothers respectively (p>0.05). The prevalence of neonatal polycythaemia was 8.2% and 2.2% for infants of hypertensive and control mothers respectively (p<0.001). The rate of delivery of SGA infants was 18.6 times higher in mothers with chronic hypertension than in mothers with pregnancy-induced hypertension (p<0.001). SGA infants born to mothers with chronic hypertension had normal mean ponderal index ( 65 2.3) while their counterparts born to mothers with pregnancy-induced hypertension had low mean ponderal index (<2.3). The prevalence of neonatal polycythaemia was 52.9% and 5.0% in infants born to mothers with chronic hypertension and infant of mothers with pregnancy-induced hypertension respectively (p<0.001). Conclusion: Maternal hypertension is associated with an increased incidence of neonatal polycythaemia and delivery of SGA infants. This risk is dramatically higher in women with chronic hypertension. Chronic maternal hypertension causes proportionate foetal growth retardation while pregnancy-induced hypertension causes disproportionate foetal growth retardation.Contexte/Objectifs: Examinerl'influence de l'hypertension maternelle sur le taux d'accouchement de nouveaux-n\ue9s petits par rapport \ue0 l'\ue2ge gestationnel, l'incidence de la polycyt\ue9mie n\ue9onatale et l'indice de poids moyen des nouveaux-n\ue9s r\ue9sultant. M\ue9thodes: A partir de la longueur et du poids de naissance, l'indice pond\ue9ral d'enfants petits par rapport \ue0 l'\ue2ge gestationnel n\ue9s de m\ue8res souffrant d'hypertension chronique a \ue9t\ue9 compar\ue9 \ue0 celui d'enfants n\ue9s de m\ue8res ayant une hypertension gravidique. De m\ueame la valeur de l'h\ue9matocrite de sang centrifug\ue9 de 265 enfants n\ue9s de m\ue8res dont la grossesse s'\ue9tait compliqu\ue9e d'hypertension a \ue9t\ue9 compar\ue9e \ue0 celle de 804 enfants n\ue9s de m\ue8res t\ue9moins. R\ue9sultats : Le taux d'accouchement d'enfants petits par rapport au poids de naissance \ue9tait de 82 et de 54,7 pour1000 naissances vivantes, respectivement pour les m\ue8res hypertendues et les m\ue8res normotendues (p>0.05). La pr\ue9valence de la polycyth\ue9mie n\ue9onatale \ue9tait respectivement de 8,2% et 2,2% pour les enfants de m\ue8res hypertendues et les t\ue9moins (p<0.001). Le taux d'accouchement d'enfants petits par rapport \ue0 l'\ue2ge gestationnel \ue9tait 18,6 fois plus \ue9lev\ue9 chez les femmes souffrant d'hypertension chronique par rapport aux m\ue8res ayant une hypertension gravidique (p<0.001). Les enfants petits par rapport \ue0 l'\ue2ge gestationnel n\ue9s de m\ue8res souffrant d'hypertension chronique avaient un index pond\ue9ral moyen normal ( 652.3), tandis que leurs homologues n\ue9s de m\ue8res souffrant d'hypertension gravidique avaient un faible index pond\ue9ral moyen (<2.3). La pr\ue9valence de polycyth\ue8mie n\ue9onatale \ue9tait de 52,9% et 5,0% pour les enfants n\ue9s respectivement de m\ue8res souffrant d'hypertension chronique et de m\ue8res souffrant d'hypertension gravidique (p<0.001). Conclusion : Une hypertension maternelle est associ\ue9e \ue0 une incidence \ue9lev\ue9e de polycyth\ue9mie n\ue9onatale et \ue0 un accouchement de nouveaux n\ue9s petits par rapport \ue0 l'\ue2ge gestationnel. Ce risque est dramatiquement plus \ue9lev\ue9 chez les femmes souffrant d'hypertension chronique. L'hypertension chronique maternelle entra\ueene un retard proportionn\ue9 de croissance fetal, tandis que l'hypertension gravidique entra\ueene un retard dysproportionn\ue9 de croissance foetal