Non-parametric Reconstruction of Cluster Mass Distribution from Strong Lensing: Modelling Abell 370

We describe a new non-parametric technique for reconstructing the mass distribution in galaxy clusters with strong lensing, i.e., from multiple images of background galaxies. The observed positions and redshifts of the images are considered as rigid constraints and through the lens (ray-trace) equation they provide us with linear constraint equations. These constraints confine the mass distribution to some allowed region, which is then found by linear programming. Within this allowed region we study in detail the mass distribution with minimum mass-to-light variation; also some others, such as the smoothest mass distribution. The method is applied to the extensively studied cluster Abell 370, which hosts a giant luminous arc and several other multiply imaged background galaxies. Our mass maps are constrained by the observed positions and redshifts (spectroscopic or model-inferred by previous authors) of the giant arc and multiple image systems. The reconstructed maps obtained for \a370 reveal a detailed mass distribution, with substructure quite different from the light distribution. The method predicts the bimodal nature of the cluster and that the projected mass distribution is indeed elongated along the axis defined by the two dominant cD galaxies. But the peaks in the mass distribution appear to be offset from the centres of the cDs. We also present an estimate for the total mass of the central region of the cluster. This is in good agreement with previous mass determinations. The total mass of the central region is M=(2.0-2.7) 10^14 Msun/h50, depending on the solution chosen.Comment: 14 pages(19 postscript figures), minor corrections, MNRAS in pres

Electro-absorption of silicene and bilayer graphene quantum dots

We study numerically the optical properties of low-buckled silicene and AB-stacked bilayer graphene quantum dots subjected to an external electric field, which is normal to their surface. Within the tight-binding model, the optical absorption is calculated for quantum dots, of triangular and hexagonal shapes, with zigzag and armchair edge terminations. We show that in triangular silicene clusters with zigzag edges a rich and widely tunable infrared absorption peak structure originates from transitions involving zero energy states. The edge of absorption in silicene quantum dots undergoes red shift in the external electric field for triangular clusters, whereas blue shift takes place for hexagonal ones. In small clusters of bilayer graphene with zigzag edges the edge of absorption undergoes blue/red shift for triangular/hexagonal geometry. In armchair clusters of silicene blue shift of the absorption edge takes place for both cluster shapes, while red shift is inherent for both shapes of the bilayer graphene quantum dots.Comment: 7 pages, 7 figure

Local Time-Averaged Gas Holdup in Fluidized Bed Reactor using Gamma Ray Computed Tomography Technique (CT)

Many Invasive and Non-Invasive Techniques Have Been Used to Analyze the Hydrodynamics of Fluidized Beds. in This Study, the Effect of Superficial Gas Velocity and Bed Particle Density on the Hydrodynamics of Gas–solid Fluidized Beds Was Investigated by using a Cylindrical Plexiglas Fluidized Bed Column, 14 Cm in Diameter. Air at Room Temperature Was Used as the Fluidizing Gas and Two Different Geldart Type-B Particles Were Used: Glass Beads and Copper Particles with Material Densities of 2.5 and 5.3 G/cm3, Respectively, with the Same Size Particle, 210 µm. to Measure the Time-Averaged Cross-Sectional Gas and Solid Holdup Distribution, Gamma Ray Computed Tomography Was Used for the First Time as a Non-Invasive Technique Instead of using X-Rays (Due to the Height Attenuation of the Copper Particles). the Results Show that Gas Holdup Increases by Increasing the Superficial Gas Velocity, and Decreasing the Particle Density Increases the Gas Holdup in the Bed

Integrated DPSIR-ANP-SD framework for Sustainability Assessment of Water Resources System in Egypt

Abstract: Nowadays fresh water severe scarcity is a global concern and it is alarming for the future. In order to fully understand the progress of the water system and its impacts, a sustainability assessment of water resources is needed. This accelerates the achievement of sustainability and management of water resources. This work aims to assess the sustainability of the water resources system by applying the integration approach proposed by (Xu, 2011). This integration approach is based on integrating the DPSIR-ANP method to the System Dynamics (SD) model, which is considered as a unique work in water resources management field. SD is a computer simulation model to understanding the behavior of complex systems over time, while Analytic Network Process (ANP) is a decision finding method used in model complex decision problems which contains feedback connections and loops. DPSIR is an analytical framework for describing the interactions between the economy, society and the environment. This integrated approach enables decision makers to view the sustainability problems of water resources system more comprehensively. The results showed that there is an increasing impact on the sustainability of water resources systems in Egypt over the research period. This is attributed to the increase in water resources consumption due to the increase in population, agriculture expansion and an increase in the value of GDP. So, the officials for managing water resources in Egypt should take actions to increase the efficiency of water use and increasing the renewable water resources for compensating water shortage

Assessment of new scale-up methodology of hydrodynamics similarity in gas-solid fluidized beds using advanced non-invasive measurement techniques (CT and RPT)

The present study assesses and validates a new mechanistic scale-up approach proposed in our laboratory. The proposed hypothesis takes into account both global as well as local hydrodynamics, which based on maintaining similar radial or diameter profiles or cross-sectional distribution of gas holdup in two different gas-solid fluidized beds at different conditions and sizes with similar design and configuration in order to achieve hydrodynamics similarity since the gas dynamic dictates the bed hydrodynamics. The experimental conditions were based on Al-Dahhan et al., (2014). They identified the conditions that provided them with closer or similar radial profiles of gas or solids holdups (gas holdup + solid holdup = 1) by implementing computational fluid dynamic (CFD) as an enabling tool to search for these conditions. In this work the experimental validity was performed by utilizing advanced non-invasive measurement techniques, computed tomography technique (CT) was used to measure gas and solid holdups at different axial levels and radioactive particle tracking (RPT) was also used to measure particle velocity field and turbulence parameters (Reynolds stress, normal stresses, turbulent kinetic energy, turbulent eddy diffusivities, etc.). It is experimentally demonstrated that similarity based only on global hydrodynamics does not necessarily ensure similar flow patterns and mixing intensities. The two systems can have similar overall gas holdups but different flow patterns and mixing intensities. This indicates that two systems can be globally similar in nature, but have different local hydrodynamics. Additionally the global parameters should not be used primarily to assess scale-up methodology REFERENCES Muthanna Al-Dahhan , Shreekanta Aradhya, Faraj Zaid, Neven Ali , Thaar Aljuwaya., Scale-up and on-line monitoring of gas-solid system using advanced and non-invasive measurement techniques, Symphos 2013, 2nd International Symposium on Innovation and Technology in the Phosphate Industry, (2014)

Causal Relationship Modeling of the Implicit Theories of Emotion and Emotion Regulation in View of the Cognitive Reappraisal Strategy and Happiness

The purpose of this study was to unveil the causal relationship modeling of the implicit theories of emotion and emotion regulation in view of cognitive reappraisal strategy and happiness for the students of the Jordanian University of Science and Technology (JUST). Based on scientific foundations, the study has constructed a proposed causal relationship model using path analysis for interpreting happiness. To achieve this goal, the emotion regulation, by Gross and John (2003), the implicit theories of emotion Scale of Livingstone, (2012), and the Oxford Happiness Inventory were employed. The sample consisted of 350 students who were chosen on availability grounds. The results of the study showed no statistically significant differences between the proposed and the optimal causal relationship models due to high matches on: AGFI=0.90, NFI=0.98, GFI=0.99, TLI =0.933, CFI=0.99, RMR=0.022. Thus, the model explained the relationships proposed and represented the optimal causal relationship model for the variables of the study

Modified dual active bridge DC/DC converter with improved efficiency and interoperability in hybrid LCC/VSC HVDC transmission grids

DC transmission grids are the promising electrical networks in the near future especially with the high penetration of large scale renewables. This paper proposes a modified version of the dual active bridge (DAB) DC/DC converter with AC link capacitors generating reactive power to compensate for non-active power consumption; hence mitigating current stresses and losses to improve efficiency. The proposed topology also enables the connectivity of current source line-commutated HVDC and voltage source HVDC technologies particularly during power reversal; a feature which conventional DAB is incapable of doing. Analysis and detailed design of the proposed converter are addressed and a comparative performance analysis is carried out with conventional DAB. Converter principle of operation is explained and Matlab/Simulink simulations are carried out to verify converter operation particularly under adverse conditions such as rated power reversal and DC fault conditions. A low scale prototype substantiates the theoretical analysis and simulation results

Life Adaptation Program & Its Effect on Daily Living Skills of Autistic Children and Their Parents Stress

This study aimed to investigate the effect of life adaptation program on daily living skills (DLS) of autistic children and their parent's stress. A quasi -experimental design was utilized in this study. A purposive sample of thirty autistic children and their parents were recruited from Autism Day Care Unit-Beit El-shams- Child Psychiatry Clinic in El-Abbassia Mental Health Hospital. Three tools were used to conduct the current study, sociodemographic and medical data sheet, autistic child skills scale, and parent's stress scale. The results showed that, more than eighty percent of the studied children had low level of daily living skills, and slightly more than half of the studied parents had moderate stress level. Findings revealed that there was a highly statistically significant difference between pre-post program regarding daily living skills & there was a highly statistically significant difference between parents stress pre and post program. In conclusion, early intervention play significant role in the development of DLS of all ages, yet further researches are needed for developing and maintenance of DLS of autistic children. Keywords: autistic disorder, daily living skills, parents stress

Modified variable step-size incremental conductance MPPT technique for photovoltaic systems

A highly efficient photovoltaic (PV) system requires a maximum power point tracker to extract peak power from PV modules. The conventional variable step-size incremental conductance (INC) maximum power point tracking (MPPT) technique has two main drawbacks. First, it uses a pre-set scaling factor, which requires manual tuning under different irradiance levels. Second, it adapts the slope of the PV characteristics curve to vary the step-size, which means any small changes in PV module voltage will significantly increase the overall step-size. Subsequently, it deviates the operating point away from the actual reference. In this paper, a new modified variable step-size INC algorithm is proposed to address the aforementioned problems. The proposed algorithm consists of two parts, namely autonomous scaling factor and slope angle variation algorithm. The autonomous scaling factor continuously adjusts the step-size without using a pre-set constant to control the trade-off between convergence speed and tracking precision. The slope angle variation algorithm mitigates the impact of PV voltage change, especially during variable irradiance conditions to improve the MPPT efficiency. The theoretical investigations of the new technique are carried out while its practicability is confirmed by simulation and experimental results

Non-parametric mass reconstruction of A1689 from strong lensing data with SLAP

We present the mass distribution in the central area of the cluster A1689 by fitting over 100 multiply lensed images with the non-parametric Strong Lensing Analysis Package (SLAP, Diego et al. 2004). The surface mass distribution is obtained in a robust way finding a total mass of 0.25E15 M_sun/h within a 70'' circle radius from the central peak. Our reconstructed density profile fits well an NFW profile with small perturbations due to substructure and is compatible with the more model dependent analysis of Broadhurst et al. (2004a) based on the same data. Our estimated mass does not rely on any prior information about the distribution of dark matter in the cluster. The peak of the mass distribution falls very close to the central cD and there is substructure near the center suggesting that the cluster is not fully relaxed. We also examine the effect on the recovered mass when we include the uncertainties in the redshift of the sources and in the original shape of the sources. Using simulations designed to mimic the data, we identify some biases in our reconstructed mass distribution. We find that the recovered mass is biased toward lower masses beyond 1 arcmin (150 kpc) from the central cD and that in the very center we may be affected by degeneracy problems. On the other hand, we confirm that the reconstructed mass between 25'' and 70'' is a robust, unbiased estimate of the true mass distribution and is compatible with an NFW profile.Comment: 11 pages, 12 figures. MNRAS submitted. A full resolution of the paper can be found in http://darwin.physics.upenn.edu/SLAP