Highly dispersible and uniform size Cu2ZnSnS4 nanoparticles for photocatalytic application

Highly dispersible, uniform size (～7 nm) single-phase Cu₂ZnSnS₄ nanoparticles have been synthesized by hydrothermal method using non-toxic surfactant (oleic acid). High resolution transmission electron microscopy image indicates good crystallinity of the Cu₂ZnSnS₄ nanoparticles with the growth along (1 1 2) plane. X-ray photoelectron spectroscopy analyses suggested that the formation of with Cu, Zn, and Sn in +1, +2 and +4 oxidation states. The optical absorption spectrum of Cu₂ZnSnS₄ nanoparticles exhibits an absorption in the visible region and its optical band gap was found to be ～1.72 eV, which could be much more appropriate for photocatalytic application under visible light irradiation. These Cu₂ZnSnS₄ nanoparticles have been shown high photocatalytic degradation activity of methylene blue (MB) dye in the presence of visible light irradiation. The rate constant (k) value of Cu₂ZnSnS₄ nanoparticles is found to be 0.0144 min^?1. We have discussed the mechanism of dye degradation process that drives the photocatalytic degradation process. The reusability of the Cu₂ZnSnS₄ nanoparticles for the dye degradation is also demonstrated.     

Surface modification of WC-Co alloy using Al and Si powder through WEDM: A thermal erosion process

This paper presents the surface modification of WC-Co alloy with the use of aluminum and silicon powder in wire electric discharge machining (WEDM) process. A separate attachment with the stirrer is used to mix the metal powder in the dielectric, which is further supplied by a pump at the workplace continuously. The effects of different process parameters like peak current, pulse on-time, pulse off-time and servo-voltage are investigated on the material transfer, crack formation and white-layer formation with the help of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis. It was observed that silicon powder enhances the surface quality (4?µm white layer) compared with aluminum (6?µm white layer) powder. The white-layer thickness without the use of metal powder was around 14?µm. The cracks density after the addition powders reduces significantly.     

A generalized search scheme for automatic registration of remote-sensing data

A generalized search scheme for automatic registration of level-1 data of multiresolution and multi-sensor remote-sensing data was proposed. The robustness and time efficiency of the automatic registration process is critically dependant on the search scheme for identification of control points. The proposed method consists of three levels of search ranging from coarser to finer. This process was found to be capable of registering images to sub-pixel level which are independent of rotation and scale variations, and also translation that vary by few metres to kilometres. In order to reduce the low pass effect due to multiple transformations involved in the multi-level registration process, a direct correspondence between the reference image and target image was established so that a single resampling needs to be applied. This correspondence also helps to generate products at any desired pixel size and to keep the original resolution intact. In this scheme mutual information (MI) is used as a similarity measure and a non-rigid transformation, thin plate spline (TPS), is used for achieving sub-pixel registration accuracies. MI is found to be better for identification of match points even for images that are radiometrically nonlinear. Unlike global transformation methods, use of non-rigid transformations such as TPS achieves sub-pixel accuracy in the moderate hilly regions as well as high hilly regions where relief displacements are high, provided sufficient number of control points are generated. However TPS transformation demands accurate control points. A robust method for detection of inaccurate control points was adopted and explained in the paper. The scheme was tested on a number of combinations of remote sensing data of the same resolution and different resolution datasets, namely Cartosat-1 with Liss-4 of Resourcesat-1, Landsat Thematic Mapper (TM) with IRS-1C/1D and Cartosat-1 with Enhanced Thematic Mapper (ETM). The results are presented along with accuracies achieved.     

The presence and development of competency in IT programs

Information technology (IT) programs are coordinated IT projects with a common business objective or underlying similar theme. Driving success in an IT program requires that the projects all work to achieve more global organizational goals than those of each individual project. These goals are better achieved in the presence of critical program team competences that include personnel development, dissemination of methodologies, and a key customer focus. These competences need to be developed to promote higher program performance where programs are dedicated to achieving business objectives of an organization. We propose a model based on the human resource model that considers the development of the critical competences when essential self and social competences are present in team members. Participation mechanisms of interpersonal cooperation and mutual support assist in the development of the critical competences. The model is supported by data collected from both quantitative survey and qualitative interviews with matched pairs of IT program managers and IT project managers. The results confirm the need to insure the presence of certain competences in team members and the construction of an environment that builds mutual support and cooperation. The human resource model is thus extended to include the inter-team environment of IT programs and further variables important to vendor competence.     

Efficient detection of a locally stable predicate in a distributed system

We present an efficient approach to detect a locally stable predicate in a distributed computation. Examples of properties that can be formulated as locally stable predicates include termination and deadlock of a subset of processes. Our algorithm does not require application messages to be modified to carry control information (e.g., vector timestamps), nor does it inhibit events (or actions) of the underlying computation. The worst-case message complexity of our algorithm is O(n(m+1))$O(n(m+1))$, where n$n$ is the number of processes in the system and m$m$ is the number of events executed by the underlying computation. We show that, in practice, its message complexity should be much lower than its worst-case message complexity. The detection latency of our algorithm is O(d)$O(d)$ time units, where d$d$ is the diameter of communication topology. Our approach also unifies several known algorithms for detecting termination and deadlock. We also show that our algorithm for detecting a locally stable predicate can be used to efficiently detect a stable predicate that is a monotonic function of other locally stable predicates.     

Dynamic height anomaly from Argo profiles and sea-level anomaly from satellite altimetry: a comparative study in the Indian Ocean

Altimeter-derived sea-level anomaly (SLA) has been compared with Argo-derived dynamic height anomaly (DHA) in the Indian Ocean. The anomalies have been found to agree quite well in the region above 10°S. The agreement is improved when climatological salinity is replaced by Argo salinity. Seasonal variation of correlation of DHA computed with Argo salinity and SLA has also been studied. The reasons for the poor correlation could be attributed to the fact that there is a barotropic (non-steric) component of the SLA, not captured by DHA, which is a purely steric effect. It has been also found that the impact of halosteric component on dynamic height is quite high in certain regions of the Arabian Sea because of (i) low-salinity water of southern region advected into the region by Somali and North Equatorial Current, (ii) upwelled water of low salinity during south-west monsoon along the Arabian coast and (iii) precipitation and river run-off from rivers in the eastern Arabian sea contributing to the local formation of low-salinity water. In the Bay of Bengal, the factors responsible for the large impact of halosteric component are precipitation and river influx in the northern part. In the south-eastern Indian Ocean, Indonesian Throughflow is the governing factor for this impact.     

Relativistic modelling of a superdense star containing a charged perfect fluid

The paper presents a variety of classes of interior solutions of the Einstein-Maxwell field equations for a static, spherically symmetric distribution of a charged fluid of well-behaved nature. They describe perfect fluid balls with positive finite central pressure and density; their ratio is less than one (c = 1), and the causality condition is obeyed at the center. The outmarch of pressure, density, pressuredensity ratio and the adiabatic speed of sound is a monotonic decrease, in a physically appealing manner. A certain class of these well-behaved solutions is studied extensively. For this class, the mass of the configuration is maximized. In particular, for a surface density ?? _b = 2×10¹⁴ g/cm³ we obtain a star with a maximummass of 3.47M _??, a radius of 15.21 km and the central redshift 1.014385.     

A novel minimum delay maximum flow multicast algorithm to construct a multicast tree in wireless mesh networks

The construction of multicast tree within given constraints, such as delay and capacity, is becoming a major problem in many wireless networks, especially wireless mesh networks (WMN). Due to the limited capacity of the wireless node, a multicast call may be dropped if there is no multicast tree formed within the given constraints. In this paper, we propose a new multicast tree construction algorithm which has maximum traffic flow and minimum delay under capacity constraints. The problem of multicast is formulated as a Linear Programming (LP) problem with associated constraints. A cost function (CF) is defined to choose the less loaded route among the available ones. A Minimum Delay Maximum Flow Multicast (MDMF) algorithm is proposed to solve this problem using CF and associated constraints. The performance of the proposed algorithm and CF is evaluated and compared with well-known algorithms with respect to packet delivery fraction, latency, and network throughput. The results obtained show that the proposed algorithm has a lesser number of transmissions for a given CF. Moreover, the proposed algorithm has high throughput, packet delivery fraction and less latency compared to other well-known algorithms in this category.     

Use of the Long-Term Pavement Performance Database in the Pavement Engineering Curriculum

In this paper the writers demonstrate the inclusion of the Long-Term Pavement Performance (LTPP-DATAPAVE 3.0) data within the pavement engineering curriculum at Michigan State University (MSU). The paper presents two examples, one from an undergraduate course on pavement rehabilitation and one from a graduate course on pavement analysis and design. These examples illustrate the use of LTPP data in computing responses, predicting traffic, developing rehabilitation strategies, and predicting performance of both rigid and flexible pavements.     

A New Technique for Forecasting Surface Wind Field From Scatterometer Observations: A Case Study for the Arabian Sea

The possibility of predicting ocean-surface wind field a few days ahead from satellite scatterometer observations in the Arabian Sea has been explored in this paper. The prediction technique is based on a combination of empirical orthogonal function (EOF) analysis and genetic algorithm (GA). The space-time distributed satellite data (zonal or meridional wind field) have been decomposed into a set of spatial eigenmodes ranked by their temporal variance. The associated temporal amplitude functions have been used by the GA for carrying out forecasts with lead times varying from one to five days. The GA finds the analytical equations that best describe the behavior of the different temporal amplitude functions in the EOF decomposition. Later, the predicted wind field has been generated as a linear combination of the dominant spatial modes weighted by the corresponding predicted amplitudes. The technique has been tested using independent validation data sets. It has been further tested by comparing the forecast fields with buoy data. The performance of GA is comparable to that of persistence forecast for the first two days of forecast, while it is better than that of persistence for three- to five-day-ahead forecasts