Finding RR Lyrae Stars with SkyMapper: an Observational Test

One of the major science goals of the SkyMapper Survey of the Southern Hemisphere sky is the determination of the shape and extent of the halo of the Galaxy. In this paper we quantify the likely efficiency and completeness of the survey as regards the detection of RR Lyrae variable stars, which are excellent tracers of the halo stellar population. We have accomplished this via observations of the RR Lyrae-rich globular cluster NGC 3201. We find that for single epoch uvgri observations followed by two further epochs of g, r imaging, as per the intended three-epoch survey strategy, we recover known RR Lyraes with a completeness exceeding 90%. We also investigate boundaries in the gravity-sensitive single-epoch two-color diagram that yield high completeness and high efficiency (i.e., minimal contamination by non-RR Lyraes) and the general usefulness of this diagram in separating populations.Comment: 10 pages, 5 figures, to appear in the Publications of the Astronomical Society of Australia (PASA), published by Cambridge University Pres

Robust detection, isolation and accommodation for sensor failures

The objective is to extend the recent advances in robust control system design of multivariable systems to sensor failure detection, isolation, and accommodation (DIA), and estimator design. This effort provides analysis tools to quantify the trade-off between performance robustness and DIA sensitivity, which are to be used to achieve higher levels of performance robustness for given levels of DIA sensitivity. An innovations-based DIA scheme is used. Estimators, which depend upon a model of the process and process inputs and outputs, are used to generate these innovations. Thresholds used to determine failure detection are computed based on bounds on modeling errors, noise properties, and the class of failures. The applicability of the newly developed tools are demonstrated on a multivariable aircraft turbojet engine example. A new concept call the threshold selector was developed. It represents a significant and innovative tool for the analysis and synthesis of DiA algorithms. The estimators were made robust by introduction of an internal model and by frequency shaping. The internal mode provides asymptotically unbiased filter estimates.The incorporation of frequency shaping of the Linear Quadratic Gaussian cost functional modifies the estimator design to make it suitable for sensor failure DIA. The results are compared with previous studies which used thresholds that were selcted empirically. Comparison of these two techniques on a nonlinear dynamic engine simulation shows improved performance of the new method compared to previous technique

Self modulated dynamics of a relativistic charged particle beam in plasma wake field excitation

Self modulated dynamics of a relativistic charged particle beam is reviewed within the context of the theory of plasma wake field excitation. The self-consistent description of the beam dynamics is provided by coupling the Vlasov equation with a Poisson-type equation relating the plasma wake potential to the beam density. An analysis of the beam envelope self-modulation is then carried out and the criteria for the occurrence of the instability are discussed thereby.Comment: This is a 10 pages manuscript which contain 4 figures. This manuscript is recently submitted in 'Nuclear Instruments and Methods in Physics Research Section A' as a proceeding of the conference 'EAAC 2015

Sensor failure detection for jet engines

Revisions to the advanced sensor failure detection, isolation, and accommodation (DIA) algorithm, developed under the sensor failure detection system program were studied to eliminate the steady state errors due to estimation filter biases. Three algorithm revisions were formulated and one revision for detailed evaluation was chosen. The selected version modifies the DIA algorithm to feedback the actual sensor outputs to the integral portion of the control for the nofailure case. In case of a failure, the estimates of the failed sensor output is fed back to the integral portion. The estimator outputs are fed back to the linear regulator portion of the control all the time. The revised algorithm is evaluated and compared to the baseline algorithm developed previously

Groundwater Modelling of Dhaka City and Surrounding Areas and Evaluation of the Effect of Artificial Recharge to Aquifers

Dhaka city lies on the Madhupur Clay overlying the Plio-Pliestocene Dupi Tila Formation which forms the principal aquifer. Massive withdrawal of water from this aquifer caused fall of water table at an alarming rate which might provoke subsidence, ecological and environmental hazards [1]. It has been found that the aquifer system of the study area can be divided in to four aquifers and four aquitards up to a depth of 400m. The long term hydrographs for the observation wells within the Dhaka City shows a sharp decline of water level with little or even no fluctuation which indicates over exploitation of aquifers [2]. The water table contour maps of wet and dry season show a pointed cone of depression in the central part of the study area. The research work has been carried out to predict the future response of groundwater level after 20 years for increasing abstraction and assessment of the USAbility of the artificial recharge of aquifers of the Dhaka City using groundwater modelling technique. An eight layer transient groundwater flow model was set up with time steps of a month using MODFLOW. Two model scenarios were considered for model prediction. For the first scenario it has been found that after 20 years the elevation of groundwater level will decline to about -120m in the central part of the Dhaka City, and the mega cone of depression will spread over an area of about 1962 km2. For the second scenario substantial water is injected into the aquifer for recharging the aquifer artificially. The quantity of artificially recharged water was equal to the abstraction of water in Dhaka City. The model predicted that the elevation of the groundwater level after 20 years of pumping will not decline anymore and will be fixed at 70m which is the present minimum groundwater level. The area of the mega cone of depression around Dhaka city will reduce by 945km2 for the next 20 years. As a consequence of artificial recharge predicted environmental degradation in and around Dhaka City can be prevented

Sensor failure detection system

Advanced concepts for detecting, isolating, and accommodating sensor failures were studied to determine their applicability to the gas turbine control problem. Five concepts were formulated based upon such techniques as Kalman filters and a screening process led to the selection of one advanced concept for further evaluation. The selected advanced concept uses a Kalman filter to generate residuals, a weighted sum square residuals technique to detect soft failures, likelihood ratio testing of a bank of Kalman filters for isolation, and reconfiguring of the normal mode Kalman filter by eliminating the failed input to accommodate the failure. The advanced concept was compared to a baseline parameter synthesis technique. The advanced concept was shown to be a viable concept for detecting, isolating, and accommodating sensor failures for the gas turbine applications

Rural finance policies for food security of the poor

The objective of IFPRI's multicountry research program on rural financial policies for food security of the poor is to identify policies and institutional arrangements that help the poor integrate themselves into sustainable savings and credit systems such that they have an increased capacity to invest, bear risk, and smooth consumption. The focus of the research on policy and program design and their effects on household investment and consumption requires field data collection at the institutional and household level. This paper presents the underlying conceptual framework and various methodological approaches that have been reviewed and tested by the team at IFPRI and at collaborating institutions. Methodologies are presented for analysis at the institutional level, mainly focusing on the determinants of the formation of financial institutions and the analysis of effects of program design on institutional conduct and performance, and at the household level, thereby addressing determinants of access to and participation in financial markets and related effects on household welfare.Food security Developing countries. ,Financial institutions. ,Households Economic aspects. ,

BRICS: Is the Group Really Creating Impact?

In 2001, Jim O'Neill coined the acronym for Brazil, Russia, India and China as the largest emerging markets economies. He expected them to grow faster than the developed countries and to play an increasingly important role in the world. In 2009, BRIC countries held their first summit which in its 3rd summit turned into BRICS with the addition of South Africa. The BRICS now represent 3 billion people and a combined GDP of $16 trillion. The group is the third giant after the EU and the US. Analysts predict that the BRICS will overtake US in terms of GDP this year and the G7 by 2030. In the summit in July 2014, BRICS leaders have approved creating the BRICS New Development Bank which would fund long-term investment in infrastructure and more sustainable development. The economics projections show that till 2040, the BRICS is expected to rule the world market

HYTESS: A hypothetical turbofan engine simplified simulation

A users manual for a hypothetical turbofan engine simplified simulation is presented. This digital simulation exists as FORTRAN source code. The program is self-contained and was developed to offer those interested in engine dynamics and controls research an efficient, realistic, and easily used engine simulation. The engine is modeled using a state space formulation. Matrix elements within the linear state space structure are nonlinear functions of various engine variables

Amelioration of a saline sodic soil through cultivation of a salt-tolerant grass Leptochloa fusca

Reclamation of saline lands seems difficult for climatic and economic reasons, but cultivation of salt-tolerant plants is an approach to increasing productivity and improvement of salt-affected wastelands. A five-year field study was conducted to evaluate the effects of growing a salt-tolerant species Leptochloa fusca (L.) Kunth (kallar grass) on chemical properties of a saline sodic soil irrigated with poor quality groundwater. Soil salinity, sodicity and pH decreased exponentially by growing kallar grass as a result of leaching of salts from surface (0–20 cm) to lower depths (>100 cm). Concentrations of soluble cations (Na+, K+, Ca2+ and Mg2+) and anions (Cl−, SO42− and HCO3−) were reduced through to greater soil depths. A significant decline in soil pH was attributed to release of CO2 by grass roots and solublization of CaCO3. Both soil salinity and soil pH were significantly correlated with Na+, Ca2+, Mg2+, K+, Cl−, HCO3− and sodium adsorption ratio (SAR). Significant correlations were found between soluble cations (Na+, Ca2+ and K+), soluble anions (Cl−, SO42− and HCO3−) and the SAR. In contrast, there were negative correlations between soil organic matter content and all chemical properties. The ameliorative effects on the soil chemical environment were pronounced after three years of growing kallar grass. Cultivation of kallar grass enhanced leaching and interactions among soil chemical properties and thus restored soil fertility. The soil maintained the improved characteristics with further growth of the grass up to five years suggesting that growing salt-tolerant plants is a sustainable approach to biological amelioration of saline wastelands.J. Akhter, K. Mahmood, K.A. Malik, S. Ahmed and R. Murra