Fracture Behaviour of 20MnMoNi55 Steel in DBT Region under Corrosive Environment

AbstractDifferent mechanical properties like strength, fracture toughness and fatigue life of structural components reduce due to corrosion of the material. In this paper the effect of corrosion on fracture toughness in ductile to brittle transition (DBT) region of 20MnMoNi55 steel is investigated. The corrosion properties of the material are measured by electrochemical impedance spectroscopy (EIS) test. The loss of ductility and fracture toughness due corrosion is measured by measuring master curve reference temperature in DBT region. Both single and multi–temperature method is used to measure the master curve reference temperature for both base material and corroded specimen. A comparative study is made to measure embrittlement that occurs due to corrosion in DBT region. From the EIS study it has been observed that the corrosion resistance properties decrease with time when the material corroded. Also the embrittlement occurring due to corrosion is reflected in the shift in master curve

Tropical cyclone intensity prediction over the North Indian Ocean - An NWP based objective approach

A Numerical Weather Prediction (NWP) based objective intensity prediction approach has been explored for prediction of tropical cyclone intensity over the North Indian Ocean (NIO) using ECMWF model outputs. The intensity of a tropical cyclone is classified by the maximum sustained wind (10-min mean) according to World Meteorological Organization (WMO). An empirical relationship between the difference of the model’s maximum mean sea level pressure (MSLP) inside a 6° × 6° grid box around the centre of the system and the lowest mean sea level pressure at the centre of the system (ΔP) with the observed intensity is developed using over 100 analyses during 2010–2012. The same is used to predict intensity of very severe cyclonic storm Hudhud and a Deep Depression observed over the Bay of Bengal during 2014. The results show that the empirical equation is skillful in prediction of intensity as compared to predictions computed using the relationship (V_{max} = K sqrt(Delta P)) with different constant values of K. The error analyses show that the relative error in intensity prediction using the empirical equation derived in the present study is 34% less than the same using (K = 14.2 kt/sqrt(hPa)) in (V_{max} = K sqrt(Delta P)) with an improvement which is significant at the level of 0.95.U radu je istražena metoda objektivne prognoze intenziteta tropskih ciklona nad Sjeverno-indijskim oceanom (NIO) temeljm numeričke prognoze vremena (NWP) modelom Europskog centra za srednjoročnu prognozu vremena (ECMWF). Intenzitet tropskog ciklona klasificira se prema prema Svjetskoj meteorološkoj organizaciji (WMO) na temelju maksimalnog vjetra (10-minutni srednjak). Upotrebom preko 100 analiza tijekom 2010. – 2012. izvedena je empirijska relacija koja povezuje razliku između najvećeg srednjeg tlaka zraka na razini mora (MSLP) unutar kvadrata mreže 6° × 6° oko središta sustava i najnižeg srednjeg tlaka na razini mora u središtu sustava (Δ P) s opaženim intenzitetom ciklona. Dobivena relacija primjenjena je na prognozu intenziteta olujnih ciklona Hudhud i Deep Depression (Duboka depresija) koji su opaženi u Bengalskom zaljevu tijekom 2014. godine. Rezultati pokazuju da empirijska jednadžba prognozira intenzitet ciklona uspješnije od prognoza izračunatih pomoću relacije (V_{max} = K sqrt(Delta P)) s različitim konstantnim vrijednostima K. Analize pogrešaka pokazuju da je relativna pogreška u prognozi intenziteta primjenom dobivene empirijske jednadžbe 34% manja od pogreške pri korištenju relacije (K = 14.2 kt/sqrt(hPa)) u (V_{max} = K sqrt(Delta P)), a poboljšanje je značajno na razini signifikantnosti od 0,95

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV