9,309 research outputs found

    Flexural Fatigue Analysis of Concrete made with 100% Recycled Concrete Aggregates

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    The paper presents results of an investigation to study the flexural fatigue performance of concrete beams made with 100% Coarse Recycled Concrete Aggregates (RCA). Experimental investigation has been carried out to obtain the flexural fatigue lives of concrete beam specimens of size 100 × 100 × 500 mm at various stress levels under four point flexural fatigue loading. The test data is used to plot the S-N curves and a simple regression analysis is used to propose an equation to estimate the flexural fatigue strength of concrete made with 100% RCA. The flexural fatigue performance of concrete made with 100% RCA has been assessed in terms of its mean and design fatigue lives. Two million cycles fatigue strength/endurance limit has also been estimated and compared with the previous studies available on Natural Aggregates (NA).

    On the NP-Hardness of Approximating Ordering Constraint Satisfaction Problems

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    We show improved NP-hardness of approximating Ordering Constraint Satisfaction Problems (OCSPs). For the two most well-studied OCSPs, Maximum Acyclic Subgraph and Maximum Betweenness, we prove inapproximability of 14/15+ϵ14/15+\epsilon and 1/2+ϵ1/2+\epsilon. An OCSP is said to be approximation resistant if it is hard to approximate better than taking a uniformly random ordering. We prove that the Maximum Non-Betweenness Problem is approximation resistant and that there are width-mm approximation-resistant OCSPs accepting only a fraction 1/(m/2)!1 / (m/2)! of assignments. These results provide the first examples of approximation-resistant OCSPs subject only to P ≠\neq \NP

    A system for production of defective interfering particles in the absence of infectious influenza A virus

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    <div><p>Influenza A virus (IAV) infection poses a serious health threat and novel antiviral strategies are needed. Defective interfering particles (DIPs) can be generated in IAV infected cells due to errors of the viral polymerase and may suppress spread of wild type (wt) virus. The antiviral activity of DIPs is exerted by a DI genomic RNA segment that usually contains a large deletion and suppresses amplification of wt segments, potentially by competing for cellular and viral resources. DI-244 is a naturally occurring prototypic segment 1-derived DI RNA in which most of the PB2 open reading frame has been deleted and which is currently developed for antiviral therapy. At present, coinfection with wt virus is required for production of DI-244 particles which raises concerns regarding biosafety and may complicate interpretation of research results. Here, we show that cocultures of 293T and MDCK cell lines stably expressing codon optimized PB2 allow production of DI-244 particles solely from plasmids and in the absence of helper virus. Moreover, we demonstrate that infectivity of these particles can be quantified using MDCK-PB2 cells. Finally, we report that the DI-244 particles produced in this novel system exert potent antiviral activity against H1N1 and H3N2 IAV but not against the unrelated vesicular stomatitis virus. This is the first report of DIP production in the absence of infectious IAV and may spur efforts to develop DIPs for antiviral therapy.</p></div

    The pressure-amorphized state in zirconium tungstate: a precursor to decomposition

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    In contrast to widely accepted view that pressure-induced amorphization arises due to kinetic hindrance of equilibrium phase transitions, here we provide evidence that the metastable pressure-amorphized state in zirconium tungstate is a precursor to decomposition of the compound into a mixture of simple oxides. This is from the volume collapse ΔV across amorphization, which is obtained for the first time by measuring linear dimensions of irreversibly amorphized samples during their recovery to the original cubic phase upon isochronal annealing up to 1000 K. The anomalously large ΔV of 25.7 ± 1.2% being the same as that expected for the decomposition indicates that this amorphous state is probably a precursor to kinetically hindered decomposition. A P–T diagram of the compound is also proposed

    Design of dimensional model for clinical data storage and analysis

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    Current research in the field of Life and Medical Sciences is generating chunk of data on daily basis. It has thus become a necessity to find solutions for efficient storage of this data, trying to correlate and extract knowledge from it. Clinical data generated in Hospitals, Clinics & Diagnostics centers is falling under a similar paradigm. Patient’s records in various hospitals are increasing at an exponential rate, thus adding to the problem of data management and storage. Major problem being faced corresponding to storage, is the varied dimensionality of the data, ranging from images to numerical form. Therefore there is a need for development of efficient data model which can handle this multi-dimensionality data issue and store the data with historical aspect. For the stated problem lying in façade of clinical informatics we propose a clinical dimensional model design which can be used for development of a clinical data mart. The model has been designed keeping in consideration temporal storage of patient's data with respect to all possible clinical parameters which can include both textual and image based data. Availability of said data for each patient can be then used for application of data mining techniques for finding the correlation of all the parameters at the level of individual and population

    Early Patterns of Commercialization of Graphene

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    Recovery Ventilation and Oxygen Debt-A Mathematical Model for the Prediction of Recovery Ventilation

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    A Mathematical model has been evolved for the estimation of recovery ventilation following an exercise. The model has been used to estimate recovery ventilation in moderate to heavy exercise for a period of 32 minutes. The model gives satisfactory predictions for persons of different age groups and under different environment conditions thus establishing its universal applicability

    Enhancement of Analytical OBR (Out of Band Radiation) and BER Calculation for Digital Au-dio-Video Broadcasting in Companded OFDM System using Non-Symmetric QAM/QPSK Tecniques

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    Companding transforms useful under assumption of infinite bandwidth. Under band limited conditions OBR parameter filters out. So bandwidth is a factor that decides the filter-ing out OBR on the performance of companded OFDM sys-tems. As a result filtering becomes essential under band lim-ited conditions in turn this does deteriorate the system per-formance significantly. In this paper method proposed to overcome the performance degradation. Method called non symmetric scheme based on the use of curve fitting method to find out a suitable polynomial to be used for decom-panding at the receiver. This method indeed improves the performance in comparison to existing symmetric methods when filtering is necessary for band limited conditions

    Computer aided Warship Stability Assessment

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    Computer aided warship stability assessment, software program effectively puts a ship stability expert onboard and provides ship board personnel with a rapid and accurate means to assess changes in vessel's stability. These changes may be :Routine - as the ship is loaded/unloaded in harbour or due to consumables enroute.Emergency - when the ship suffers collision/battle damage underway and begins to take on water.After assessing the stability status, the program helps the crew to determine the actions needed to restore optimum stability

    The parameterized complexity of some geometric problems in unbounded dimension

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    We study the parameterized complexity of the following fundamental geometric problems with respect to the dimension dd: i) Given nn points in \Rd, compute their minimum enclosing cylinder. ii) Given two nn-point sets in \Rd, decide whether they can be separated by two hyperplanes. iii) Given a system of nn linear inequalities with dd variables, find a maximum-size feasible subsystem. We show that (the decision versions of) all these problems are W[1]-hard when parameterized by the dimension dd. %and hence not solvable in O(f(d)nc){O}(f(d)n^c) time, for any computable function ff and constant cc %(unless FPT=W[1]). Our reductions also give a nΩ(d)n^{\Omega(d)}-time lower bound (under the Exponential Time Hypothesis)
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