A newly discovered stellar type: dusty post-red giant branch stars in the Magellanic Clouds

Context: We present a newly discovered class of low-luminosity, dusty, evolved objects in the Magellanic Clouds. These objects have dust excesses, stellar parameters, and spectral energy distributions similar to those of dusty post-asymptotic giant branch (post-AGB) stars. However, they have lower luminosities and hence lower masses. We suggest that they have evolved off the red giant branch (RGB) instead of the AGB as a result of binary interaction. Aims: In this study we aim to place these objects in an evolutionary context and establish an evolutionary connection between RGB binaries (such as the sequence E variables) and our new sample of objects. Methods: We compared the theoretically predicted birthrates of the progeny of RGB binaries to the observational birthrates of the new sample of objects. Results: We find that there is order-of-magnitude agreement between the observed and predicted birthrates of post-RGB stars. The sources of uncertainty in the birthrates are discussed; the most important sources are probably the observational incompleteness factor and the post-RGB evolution rates. We also note that mergers are relatively common low on the RGB and that stars low on the RGB with mid-IR excesses may recently have undergone a merger. Conclusions: Our sample of dusty post-RGB stars most likely provides the first observational evidence for a newly discovered phase in binary evolution: post-RGB binaries with circumstellar dust.Comment: Accepted for publication in Astronomy and Astrophysics Letter

Impact of photovoltaic distributed generation on unbalance phenomenon in distribution feeder

In a smart grid environment, voltage sensitive composite load characteristics, poor voltage profile and rapid integration of distributed generation (DG) are imperative to compute reactive power status at the point of coupling (PCC) during each iteration of load flow computation. In this work, a fuzzy expert system based photo voltaic DG placement has been utilized to evaluate stochastic unbalance phenomenon for a modified IEEE 37 node test feeder. Key performance parameters are evaluated for six different DG operational modes and compared with results obtained in the base case. By investigation of obtained stochastic unbalance results for different six PV DG operational modes, it has been observed that DG operational mode at 0.95 lead power factor is more suitable than other ways for improving unbalance phenomenon.Keywords: unbalance phenomenon; distributed generation; stochastic feeder performance

Imaging the dust sublimation front of a circumbinary disk

We present the first near-IR milli-arcsecond-scale image of a post-AGB binary that is surrounded by hot circumbinary dust. A very rich interferometric data set in six spectral channels was acquired of IRAS08544-4431 with the new RAPID camera on the PIONIER beam combiner at the Very Large Telescope Interferometer (VLTI). A broadband image in the \textit{H} band was reconstructed by combining the data of all spectral channels using the SPARCO method. We spatially separate all the building blocks of the IRAS08544-4431 system in our milliarcsecond-resolution image. Our dissection reveals a dust sublimation front that is strikingly similar to that expected in early-stage protoplanetary disks, as well as an unexpected flux signal of $\sim$4\% from the secondary star. The energy output from this companion indicates the presence of a compact circum-companion accretion disk, which is likely the origin of the fast outflow detected in H$\alpha$. Our image provides the most detailed view into the heart of a dusty circumstellar disk to date. Our results demonstrate that binary evolution processes and circumstellar disk evolution can be studied in detail in space and over time.Comment: PR @ http://www.eso.org/public/news/eso1608

Cyclic voltammetric studies of pure and doped films of cobalt hydroxide in 1M potassium hydroxide

Cyclic voltammetric studies of electrosynthetically prepd. pure and doped thin films of cobalt hydroxide (on a platinum foil substrate) in 1M KOH show that Co(OH)​2 undergoes a quasi-​reversible redox reaction between a nearly quadrivalent black oxidic phase and a trivalent brown bronze-​like phase. The coulombic efficiency is 60​%. A common scheme is proposed for the electrode reactions of oxide electrodes in alk. media, namely: MII(OH)​2 .dblharw. HMIIIO2 .dblharw. MIVO2, where M = Mn, Co, Ni. The three metals execute different steps in this two-​electron redox reaction, either reversibly or qu..

Synthesis and reversible hydration behavior of the thiosulfate intercalated layered double hydroxide of Zn and Al

The thiosulfate-intercalated layered double hydroxide of Zn and Al undergoes reversible hydration with a variation in the relative humidity of the ambient. The hydrated and dehydrated phases, which represent the end members of the hydration cycle, both adopt the structure of the 3R1 polytype. In the intermediate range of relative humidity values (40-60), the hydrated and dehydrated phases coexist. The end members of the hydration cycle adopt the structure of the same polytype, and vary only in their basal spacings. This points to the possibility that all the intermediate phases have a kinetic origin. © 2013 Elsevier Inc

Modeling of high speed chemically reacting flow-fields

The SPARK3D and SPARK3D-PNS computer programs were developed to model 3-D supersonic, chemically reacting flow-fields. The SPARK3D code is a full Navier-Stokes solver, and is suitable for use in scramjet combustors and other regions where recirculation may be present. The SPARK3D-PNS is a parabolized Navier-Stokes solver and provides an efficient means of calculating steady-state combustor far-fields and nozzles. Each code has a generalized chemistry package, making modeling of any chemically reacting flow possible. Research activities by the Langley group range from addressing fundamental theoretical issues to simulating problems of practical importance. Algorithmic development includes work on higher order and upwind spatial difference schemes. Direct numerical simulations employ these algorithms to address the fundamental issues of flow stability and transition, and the chemical reaction of supersonic mixing layers and jets. It is believed that this work will lend greater insight into phenomenological model development for simulating supersonic chemically reacting flows in practical combustors. Currently, the SPARK3D and SPARK3D-PNS codes are used to study problems of engineering interest, including various injector designs and 3-D combustor-nozzle configurations. Examples, which demonstrate the capabilities of each code are presented

Effectiveness of specific RNA-mediated interference through ingested double-stranded RNA in Caenorhabditis elegans.

BACKGROUND: In Caenorhabditis elegans, injection of double-stranded RNA (dsRNA) results in the specific inactivation of genes containing homologous sequences, a technique termed RNA-mediated interference (RNAi). It has previously been shown that RNAi can also be achieved by feeding worms Escherichia coli expressing dsRNA corresponding to a specific gene; this mode of dsRNA introduction is conventionally considered to be less efficient than direct injection, however, and has therefore seen limited use, even though it is considerably less labor-intensive. RESULTS: Here we present an optimized feeding method that results in phenotypes at least as strong as those produced by direct injection of dsRNA for embryonic lethal genes, and stronger for genes with post-embryonic phenotypes. In addition, the interference effect generated by feeding can be titrated to uncover a series of hypomorphic phenotypes informative about the functions of a given gene. Using this method, we screened 86 random genes on consecutive cosmids and identified functions for 13 new genes. These included two genes producing an uncoordinated phenotype (a previously uncharacterized POU homeodomain gene, ceh-6, and a gene encoding a MADS-box protein) and one gene encoding a novel protein that results in a high-incidence-of-males phenotype. CONCLUSIONS: RNAi by feeding can provide significant information about the functions of an individual gene beyond that provided by injection. Moreover, it can be used for special applications for which injection or the use of mutants is sometimes impracticable (for example, titration, biochemistry and large-scale screening). Thus, RNAi by feeding should make possible new experimental approaches for the use of genomic sequence information.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Data Security using Trust by Integrating WSN and CC and Reputation Calculation Technique

: Integration of Cloud Computing and Wireless Sensor Network led tremendous growth in the development of Information Technology, during the trust and reputation of service providers for information technology play an essential role. Cloud computing is web-based computing was in the services based on the internet such as data, storage, and computing resources are delivered to the local devices through the internet. Wireless sensor network deals with monitoring, gathering of the information about the physical or environmental conditions. The integration of these two domains has tremendous advantages to improve the business infrastructure and performance worldwide. The security of data on the cloud and calculation of trust and reputation of the Cloud Service Provides (CSP) and Sensor Network Providers (SNP) are the issues for this new paradigm. To fulfill these issues This paper presents novel techniques, for 1) trust and reputation calculation 2) data security on cloud 3) choosing desirable CSP and SNP for the service. This paper proposes Data Security by taking into account the services of Wireless Sensor Network (WSN) and Cloud Service Providers. Our experimental results help users to choose the best service providers in case of both Cloud and Wireless Sensor Network. In addition to that, data security is provided using a data encryption algorithm