2,027 research outputs found

    The Extended GMRT Radio Halo Survey I: New upper limits on radio halos and mini-halos

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    A fraction of galaxy clusters host diffuse radio sources called radio halos, radio relics and mini-halos. We present the sample and first results from the Extended GMRT Radio Halo Survey (EGRHS)- an extension of the GMRT Radio Halo Survey (GRHS, Venturi et al. 2007, 2008). It is a systematic radio survey of galaxy clusters selected from the REFLEX and eBCS X-ray catalogs . Analysis of GMRT data at 610/ 235/ 325 MHz on 12 galaxy clusters are presented. We report the detection of a newly discovered mini-halo in the cluster RXJ1532.9+3021 at 610 MHz. A small scale relic (~200 kpc) is suspected in the cluster Z348. We do not detect cluster-scale diffuse emission in 11 clusters. Robust upper limits on the detection of radio halo of size of 1 Mpc are determined. We also present upper limits on the detections of mini-halos in a sub-sample of cool-core clusters. The upper limits for radio halos and mini-halos are plotted in the radio power- X-ray luminosity plane and the correlations are discussed. Diffuse extended emission, not related to the target clusters, but detected as by-products in the sensitive images of two of the cluster fields (A689 and RXJ0439.0+0715) are reported. Based on the information about the presence of radio halos (or upper limits), available on 48 clusters out of the total sample of 67 clusters (EGRHS+GRHS), we find that ~23% of the clusters host radio halos. The radio halo fraction rises to ~31%, when only the clusters with X-ray luminosities >8x10^44 erg/s are considered. Mini-halos are found in ~50 % of cool-core clusters. A qualitative examination of the X-ray images of the clusters with no diffuse radio emission indicates that a majority of these clusters do not show extreme dynamical disturbances and supports the idea that mergers play an important role in the generation of radio halos/relics.Comment: 21 pages, 18 figures, 3 tables, accepted for publication in A&

    On the occurrence of Radio Halos in galaxy clusters - Insight from a mass-selected sample

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    Giant radio halos (RH) are diffuse Mpc-scale synchrotron sources detected in a fraction of massive and merging galaxy clusters. An unbiased study of the statistical properties of RHs is crucial to constrain their origin and evolution. We aim at investigating the occurrence of RHs and its dependence on the cluster mass in a SZ-selected sample of galaxy clusters, which is as close as possible to be a mass-selected sample. Moreover, we analyse the connection between RHs and merging clusters. We select from the Planck SZ catalogue (Planck Collaboration XXIX 2014) clusters with M6×1014MM\geq 6\times10^{14} M_\odot at z=0.08-0.33 and we search for the presence of RHs using the NVSS for z<0.2 and the GMRT RH survey (GRHS, Venturi et al. 2007, 2008) and its extension (EGRHS, Kale et al. 2013, 2015) for 0.2<z<0.33. We use archival Chandra X-ray data to derive information on the clusters dynamical status. We confirm that RH clusters are merging systems while the majority of clusters without RH are relaxed, thus supporting the idea that mergers play a fundamental role in the generation of RHs. We find evidence for an increase of the fraction of clusters with RHs with the cluster mass and this is in line with expectations derived on the basis of the turbulence re-acceleration scenario. Finally, we discuss the effect of the incompleteness of our sample on this result.Comment: 11 pages, 7 figures, accepted for publication in A&

    New giant radio sources and underluminous radio halos in two galaxy clusters

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    The aim of this work is to analyse the radio properties of the massive and dynamical disturbed clusters Abell 1451 and Zwcl 0634.1+4750, especially focusing on the possible presence of diffuse emission. We present new GMRT 320 MHz and JVLA 1.5 GHz observations of these two clusters. We found that both Abell 1451 and Zwcl 0634.1+4750 host a radio halo with a typical spectrum (α11.3\alpha\sim1-1.3). Similarly to a few other cases reported in the recent literature, these radio halos are significantly fainter in radio luminosity with respect to the current radio power-mass correlations and they are smaller than classical giant radio halos. These underluminous sources might contribute to shed light on the complex mechanisms of formation and evolution of radio halos. Furthermore, we detected a candidate radio relic at large distance from the cluster center in Abell 1451 and a peculiar head tail radio galaxy in Zwcl 0634.1+4750, which might be interacting with a shock front.Comment: 15 pages, 13 figures, accepted for publication in A&

    The Extended GMRT Radio Halo Survey II: Further results and analysis of the full sample

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    The intra-cluster medium contains cosmic rays and magnetic fields that are manifested through the large scale synchrotron sources, termed as radio halos, relics and mini-halos. The Extended Giant Metrewave Radio Telescope (GMRT) Radio Halo Survey (EGRHS) is an extension of the GMRT Radio Halo Survey (GRHS) designed to search for radio halos using GMRT 610/235 MHz observations. The GRHS+EGRHS consists of 64 clusters in the redshift range 0.2 -- 0.4 that have an X-ray luminosity larger than 5x10^44 erg/s in the 0.1 -- 2.4 keV band and with declinations > -31 deg in the REFLEX and eBCS X-ray cluster catalogues. In this second paper in the series, GMRT 610/235 MHz data on the last batch of 11 galaxy clusters and the statistical analysis of the full sample are presented. A new mini-halo in RXJ2129.6+0005 and candidate diffuse sources in Z5247, A2552 and Z1953 are discovered. A unique feature of this survey are the upper limits on the detections of 1 Mpc sized radio halos; 4 new are presented here making a total of 31 in the survey. Of the sample, 58 clusters that have adequately sensitive radio information were used to obtain the most accurate occurrence fractions so far. The occurrence of radio halos in our X-ray selected sample is ~22%, that of mini-halos is 13% and that of relics is ~5%. The radio power - X-ray luminosity diagrams for the radio halos and mini-halos with the detections and upper limits are presented. The morphological estimators namely, centroid shift (w), concentration parameter (c) and power ratios (P_3/P_0) derived from the Chandra X-ray images are used as proxies for the dynamical states of the GRHS+EGRHS clusters. The clusters with radio halos and mini-halos occupy distinct quadrants in the c-w, c-P_3/P_0 and w - P_3/P_0 planes, corresponding to the more and less morphological disturbance, respectively. The non-detections span both the quadrants.Comment: 24 pages, 5 tables, 25 figures, accepted for publication in A&

    Rotational viscoelastic laminar boundary layer flow around a rotating disc

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    The equations of motion for the laminar boundary layer flow over a rotating disc have been derived for a fluid which obeys a Rivlin-Ericksen type of constitutive equation and whose material parameters are assumed to be arbitrary functions of the second invariant of the rate of deformation tensor. The analysis establishes the conditions under which a true similarity solution is possible. An inspectional analysis yields a relationship between the moment coefficient, a generalized Reynolds number and a modified Weissenberg number which incorporates a variable relaxation time with a process time characteristic of the boundary layer flow on the disc. Experimental data obtained are analysed in terms of the derived relationship and the agreement between the two, after the determination of the unknown constants, is found to be quite sound. A brief discussion follows which emphasizes the role of geometry, regime of flow and viscoelastic material parameters in giving a wide variety of flow phenomena

    Effect of Addition of Moringa Leaves (Moringa oleifera) on Chemical Characteristics and Nutritional Value of Chicken Sausage Chips

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    The leading cause of malnutrition in NTT province is the lack of balanced nutrition, one of which is macronutrients such as carbohydrates, proteins, and fats. So, there is a need for innovation from livestock products rich in readily available animal protein, one of which is chicken. Utilization of the results of heating technology Moringa leaf flour which is rich in micro and macronutrients is available in the province of NTT, so that it can provide processed products in the form of chicken sausage chips with the addition of Moringa leaf flour. This study aims to determine the effect of adding Moringa leaf flour P0, P1, P2, and P3 on chicken sausage chips' chemical characteristics and nutritional value. Each treatment P0 Moringa leaf flour (0%), P1 Moringa leaf flour (1%), P2 Moringa leaf flour (2%), P3 Moringa leaf flour (3%). The experimental method used is a simple, completely randomized design (CRD) with four treatments and four replications. Analysis of the ANOVA (Analysis of Variance) data and Duncan's further test, while the nutritional value content was calculated according to BPOM regulation NO 19 of 2019 concerning Nutrition Label Reference. The results showed that the addition of Moringa leaf flour had a significant effect on the chemical characteristics of P<0.05. According to the National Food and Drug Administration Agency (BPOM), for appropriate nutritional content, information on the nutritional value of chicken sausage chips

    Secure Cloud Computing Based On Mobile Agents

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    In this paper, we provide protection to the service requested to the cloud from user. Cloud computing is a examine sloping system that launch services to the client at low cost. According to various researches user verification is the most significant security concern and demanding issue in cloud-based environment. As cloud computing provides different advantages it also brings some of the concern about the security and privacy of information. Cloud computing requests to concentrate on three main security issues : privacy, reliability and accessibility. In this paper, we propose a new approach that provides confidentiality for the services request by the user by using mobile agents for communication between user and cloud layer; we provide security at each layer in cloud computing with Kerberos. We provide security to service which will be request to the cloud with authentication server and TGS system. DOI: 10.17762/ijritcc2321-8169.150318

    Expression of transforming growth factor ? and its correlation with lipodystrophy in oral submucous fibrosis: an immunohistochemical study

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    Objective: In our routine review of Oral Submucous Fibrosis (OSMF) biopsies, we observed decreased adipose tissue even though most are from buccal mucosa. Pathogenesis of OSMF has demonstrated the role of Transforming Growth Factor ? (TGF ?), in causing fibrosis. This study aims to correlate the role of TGF ? with loss of adipose tissue in OSMF. Study Design: From our archives, 84 OSMF cases (24 early and 60 advanced OSMF) were screened for adipose tissue. Immunoexpression of TGF ? in these cases were investigated. Results: Adipose tissue was seen in 67% of early OSMF and in 13% of advanced cases. Early cases showed more intense TGF ? staining of epithelium, fibroblast, macrophages and inflammatory cells than the advanced cases. Conclusion: These findings suggest that TGF ? plays a key role in causing lipodystrophy in OSMF and is secreted more during early course of the disease than in advanced stage

    Proof Verification and Attribute Based Re-Encryption of Shared Data over Public Cloud

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    Cloud storage is the best and proficient approach to handle our information remotely. In any case, since information proprietors and clients are more often than not outside the trusted area of cloud specialist co-ops the information security and get to control is the critical component at the season of delicate information put away in the cloud. Additionally, now days there are distinctive systems are accessible for information sharing and saving security of information proprietor and client. Key Escrow is the one of the significant issue now a day. We can’t keep full trust over the key power focus since they might be abuse their benefits. This is unsatisfactory for data sharing circumstances. In this paper we concentrated the current procedure for sharing the information from information proprietor to information client. The methodology propose an enhanced two-party key issuing convention that can ensure that neither key power nor cloud specialist co-op can bargain the entire mystery key of a client exclusively. The method also present the idea of quality with weight, being given to upgrade the statement of characteristic, which cannot just extend the expression from paired to discretionary state, additionally help the intricacy of get to approach. In this manner, both capacity cost and encryption many-sided quality for a cipher text are eased. Attribute based encryption is an open key based encryption that empowers get to control over encoded information utilizing access strategies and credited qualities. In this paper we propose proof verification module which verify proof of shared file and is received by data consumer when file shared by data owner and also a method which applies re-encryption (ABE) of a shared file here the attributes of data consumers are used to generate key

    Remote Video Monitoring System Using Raspberry Pi 3 and GPRS Module

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    Now a day’s security has prime importance in different areas such as home security, monitoring of remote areas etc. with advancement in embedded system and wireless technology, it is possible to build a remote area monitoring system with low cost. This paper represents a system implemented by using Raspberry Pi 3 and GPRS module. Transmitter section is implemented at remote area where images are captured by using USB camera interfaced with Raspberry pi. Images are compressed by software programming using libjpeg library and uploaded to HTTP server via SIM900A/800 GSM/GPRS module. Internet connection is established using PPP stack of SIM900A/800 GSM/GPRS module. Receiver section is monitoring center where images are downloaded using 3g or Wi-Fi wireless connection. Received images are decompressed and streamed on web browser using MJPG streamer
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