Istanbul Technical University

About: Istanbul Technical University is a education organization based out in Istanbul, Turkey. It is known for research contribution in the topics: Fuzzy logic & Large Hadron Collider. The organization has 12889 authors who have published 25081 publications receiving 518242 citations. The organization is also known as: İstanbul Teknik Üniversitesi & Technical University of Istanbul.

Search for anomalous production of events with three or more leptons in pp collisions at s =8TeV

Abstract: A search for physics beyond the standard model in events with at least three leptons is presented. The data sample, corresponding to an integrated luminosity of 19.5 fb^(−1) of proton-proton collisions with center-of-mass energy √s=8 TeV, was collected by the CMS experiment at the LHC during 2012. The data are divided into exclusive categories based on the number of leptons and their flavor, the presence or absence of an opposite-sign, same-flavor lepton pair (OSSF), the invariant mass of the OSSF pair, the presence or absence of a tagged bottom-quark jet, the number of identified hadronically decaying τ leptons, and the magnitude of the missing transverse energy and of the scalar sum of jet transverse momenta. The numbers of observed events are found to be consistent with the expected numbers from standard model processes, and limits are placed on new-physics scenarios that yield multilepton final states. In particular, scenarios that predict Higgs boson production in the context of supersymmetric decay chains are examined. We also place a 95% confidence level upper limit of 1.3% on the branching fraction for the decay of a top quark to a charm quark and a Higgs boson (t→cH), which translates to a bound on the left- and right-handed top-charm flavor-violating Higgs Yukawa couplings, λ^H_(tc) and λ^H_(ct), respectively, of √|λ^H_(tc)|^2+|λ^H_(ct)|^2<0.21.

Correlation of fiber dispersion, rheology and mechanical performance of FRCs

Abstract: Fresh state properties of fiber-reinforced concretes (FRCs) were correlated to hardened state properties by quantifying fiber segregation. Rheological characteristics were evaluated using a custom-designed and built parallel-plate rheometer. Fresh state properties of concrete mixes were varied using different combinations of plasticizing agents and viscosity modifiers. Vibration was applied to the specimens and vibration times were varied to understand the effects of vibration on fiber segregation. Two sizes of steel fibers were used. Alternating current-impedance spectroscopy (AC-IS) was employed to non-destructively characterize fiber segregation in the specimens. In addition, fiber segregation was experimentally quantified using a destructive technique in which the amount of fibers in different regions is weighed. A self-compacting concrete (SCC) mix was cast to compare segregation resistance with conventional concretes (CC). Splitting tensile tests were performed to study mechanical performance of FRC specimens. The effects of the rheological characteristics on fiber segregation and, consequently, on the mechanical performance is discussed.

A3‐type star polymers via click chemistry

Abstract: We report a simple preparation of three-armed (A3-type) star polymers based on the arm-first technique, using a click-reaction strategy between a well-defined azide-end-functionalized polystyrene, poly(tert-butyl acrylate), or poly(ethylene glycol) precursor and a trisalkyne-functional initiator, 1,1,1-tris[4-(2-propynyloxy)phenyl]ethane. The click-reaction efficiency for A3-type star formation has been investigated with gel permeation chromatography measurements (refractive-index detector). The gel permeation chromatography curves have been split with the deconvolution method (Gaussian area), and the efficiency of A3-type star formation has been found to be 87%. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6458–6465, 2006

Evolutionary engineering of Saccharomyces cerevisiae for improved industrially important properties

Abstract: This article reviews evolutionary engineering of Saccharomyces cerevisiae. Following a brief introduction to the 'rational' metabolic engineering approach and its limitations such as extensive genetic and metabolic information requirement on the organism of interest, complexity of cellular physiological responses, and difficulties of cloning in industrial strains, evolutionary engineering is discussed as an alternative, inverse metabolic engineering strategy. Major evolutionary engineering applications with S. cerevisiae are then discussed in two general categories: (1) evolutionary engineering of substrate utilization and product formation and (2) evolutionary engineering of stress resistance. Recent developments in functional genomics methods allow rapid identification of the molecular basis of the desired phenotypes obtained by evolutionary engineering. To conclude, when used alone or in combination with rational metabolic engineering and/or computational methods to study and analyze processes of adaptive evolution, evolutionary engineering is a powerful strategy for improvement in industrially important, complex properties of S. cerevisiae.