1,283 research outputs found

    Two and three-dimensional shock-shock interactions on the blunt leading edges of the hypersonic inlets

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    The effect of shock impingement on the blunt leading edges of the top and sidewall compression type inlet of a scramjet engine is studied numerically. The impinging shock is caused by the vehicle forebody. The interaction of this forebody shock with the inlet leading edge shock results in a very complex flowfield containing local regions of high pressure and intense heating. This complex flowfield in calculated by solving the Navier-Stokes equations using a finite volume flux splitting technique due to van Leer. To resolve the finer details of the flow structure as well as to predict the surface heat transfer accurately, adaptive grid technique is used in the analysis. Results of the present numerical study are compared with available experimental results

    Identification of multi-object dynamical systems : consistency and Fisher information

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    Learning the model parameters of a multiobject dynamical system from partial and perturbed observations is a challenging task. Despite recent numerical advancements in learning these parameters, theoretical guarantees are extremely scarce. In this article we aim to help fill this gap and study the identifiability of the model parameters and the consistency of the corresponding maximum likelihood estimate (MLE) under assumptions on the different components of the underlying multi-object system. In order to understand the impact of the various sources of observation noise on the ability to learn the model parameters, we study the asymptotic variance of the MLE through the associated Fisher information matrix. For example, we show that specific aspects of the multitarget tracking (MTT) problem such as detection failures and unknown data association lead to a loss of information which is quantified in special cases of interest. To the best of the authors' knowledge, these are new theoretically backed insights on the subtleties of MTT parameter learning

    Performance of sequential herbicides to control weeds in direct seeded rice

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    Direct seeded rice is an emerging production technology in India due to less requirement of water, labour and capital input initially. But direct seeded rice face severe infestation of weeds. A field experiment was conducted during the kharif 2012 at Students’ Farm of College of Agriculture, CCS Haryana Agricultural University; Kaul campus (Kaithal) to study the performance of sequential application of herbicides on weed flora in direct seeded rice. The herbicidal treatments included two pre emergence herbicides i.e. pendimethalin 1000 g/ha and oxadiargyl 100 g/ ha and four post emergence herbicides (bispyribac sodium 25 g/ha, fenoxaprop 67 g/ha, ethoxysulfuron 18.75 g/ha and metsulfuron methyl 10% + chlorimuron ethyl 10% WP ready mix (Almix) 4 g/ha). Weed free and weedy check were also included. The results showed that grasses were the dominant weed flora (49 %) followed by sedges (34%) and broad leaf weeds (17%).Sequential application of pendimethalin 1000 g/ha fb bispyribac sodium 25 g/ha and metsulfuron methyl + chlorimuron ethyl RM (Almix) 4 g/ha gave significantly lower weed density (p=0.05) and higher weed control efficiency which resulted in more number of effective tillers (209.3), filled grains/panicle (83.7) and grain yield (3.97 t/ha)

    On large lag smoothing for hidden Markov Models

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    In this article we consider the smoothing problem for hidden Markov models. Given a hidden Markov chain {Xn}n≥0\{X_n\}_{n\geq 0} and observations {Yn}n≥0\{Y_n\}_{n\geq 0}, our objective is to compute E[φ(X0,…,Xk)∣y0,…,yn]\mathbb{E}[\varphi(X_0,\dots,X_k)|y_{0},\dots,y_n] for some real-valued, integrable functional φ\varphi and kk fixed, k≪nk \ll n and for some realization (y0,…,yn)(y_0,\dots,y_n) of (Y0,…,Yn)(Y_0,\dots,Y_n). We introduce a novel application of the multilevel Monte Carlo method with a coupling based on the Knothe--Rosenblatt rearrangement. We prove that this method can approximate the aforementioned quantity with a mean square error (MSE) of O(ϵ2)\mathcal{O}(\epsilon^2) for arbitrary ϵ>0\epsilon>0 with a cost of O(ϵ−2)\mathcal{O}(\epsilon^{-2}). This is in contrast to the same direct Monte Carlo method, which requires a cost of O(nϵ−2)\mathcal{O}(n\epsilon^{-2}) for the same MSE. The approach we suggest is, in general, not possible to implement, so the optimal transport methodology of [A. Spantini, D. Bigoni, and Y. Marzouk, J. Mach. Learn. Res., 19 (2018), pp. 2639--2709; M. Parno, T. Moselhy, and Y. Marzouk, SIAM/ASA J. Uncertain. Quantif., 4 (2016), pp. 1160--1190] is used, which directly approximates our strategy. We show that our theoretical improvements are achieved, even under approximation, in several numerical examples

    Heterosis for Fruit Yield and its Components in Brinjal (Solanum melongena L.)

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    An experiment was conducted with 14 parents and 40 F1s to study heterosis in brinjal. Crosses showing significant heterosis over the better parent were: HE12 X Aruna for first fruit set; BR-112 X Aruna for fruit length and diameter; Pant Samrat X Punjab Neelam for number of fruits per plant; H-7 X Aruna for fruit weight; H-9 X S-16 for total yield per plant; Negative heterosis were recorded in KT-4 X Aruna for borer and Pant in Rituraj X Punjab Neelam for nematode infestation

    Holographic Quantum Critical Transport without Self-Duality

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    We describe general features of frequency-dependent charge transport near strongly interacting quantum critical points in 2+1 dimensions. The simplest description using the AdS/CFT correspondence leads to a self-dual Einstein-Maxwell theory on AdS_4, which fixes the conductivity at a frequency-independent self-dual value. We describe the general structure of higher-derivative corrections to the Einstein-Maxwell theory, and compute their implications for the frequency dependence of the quantum-critical conductivity. We show that physical consistency conditions on the higher-derivative terms allow only a limited frequency dependence in the conductivity. The frequency dependence is amenable to a physical interpretation using transport of either particle-like or vortex-like excitations.Comment: 42 pages, 7 figures. A new figure showing the frequency dependence of EM dual conductivity and few references added. Abstract, introduction, section 5 and discussion extended. To appear in Phys.Rev.

    College Enquiry Chatbot Using A.L.I.C.E

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    Innbsp thisnbsp paper,nbsp anbsp proposalnbsp isnbsp carriednbsp onnbsp tonbsp explainnbsp thenbsp designnbsp ofnbsp anbsp chatnbsp bot specifically tailored as an application which is going to help new students to solvenbsp allnbsp thenbsp problemsnbsp theynbsp facenbsp andnbsp thenbsp questionsnbsp whichnbsp arisesnbsp innbsp their mind during and after the admission . In particular, the proposal investigates the implementation of ALICE chat bot system as an application named as college enquiry chat bot. A keywords-based human-computer dialog system makes it possible that the user could chat with the computer using a natural language, i.e. in English

    Effects of Natural Zeolites on Bioavailability and Leachability of Heavy Metals in the Composting Process of Biodegradable Wastes

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    The bioavailability and leachability of heavy metals play an important role in the toxicity of heavy metals in the final compost followed by land application. This chapter examines the effects of natural zeolite on bioavailability of heavy metals (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) in the form of water soluble and diethylenetriaminepentaacetic acid (DTPA) extractable. The toxicity characteristic leaching procedure (TCLP) test was performed to examine the leachability of heavy metals. Water solubility, DTPA extractability, leachability, and most bioavailable fractions were reduced during agitated pile composting (APC) and rotary drum composting (RDC) of water hyacinth with zeolite addition. The addition of the natural zeolite (clinoptilolite) during the composting process led to an increase in Na, Ca, and K concentrations and significantly reduced the water solubility and DTPA and TCLP extractability of heavy metals. The addition of an appropriate amount of natural zeolite during the composting process enhanced the organic matter degradation, thereby increasing the conversion into the most stabilized organic matter and reducing the bioavailability and leachability of heavy metals
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