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.

Measurement of isolated-photon pair production in pp collisions at s√=7TeV with the ATLAS detector

Abstract: The ATLAS experiment at the LHC has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at root s = 7 TeV. The full data set collected in 2011, corresponding to an integrated luminosity of 4.9 fb(-1), is used. The amount of background, from hadronic jets and isolated electrons, is estimated with data-driven techniques and subtracted. The total cross section, for two isolated photons with transverse energies above 25 GeV and 22 GeV respectively, in the acceptance of the electromagnetic calorimeter (vertical bar eta vertical bar 0.4, is 44.0(-4.2)(+3.2) pb. The differential cross sections as a function of the di-photon invariant mass, transverse momentum, azimuthal separation, and cosine of the polar angle of the largest transverse energy photon in the Collins-Soper di-photon rest frame are also measured. The results are compared to the prediction of leading-order parton-shower and next-to-leading-order and next-to-next-to-leading-order parton-level generators.

Selection of multi-model ensemble of general circulation models for the simulation of precipitation and maximum and minimum temperature based on spatial assessment metrics

Abstract: . The climate modelling community has trialled a large number of metrics for evaluating the temporal performance of general circulation models (GCMs), while very little attention has been given to the assessment of their spatial performance, which is equally important. This study evaluated the performance of 36 Coupled Model Intercomparison Project 5 (CMIP5) GCMs in relation to their skills in simulating mean annual, monsoon, winter, pre-monsoon, and post-monsoon precipitation and maximum and minimum temperature over Pakistan using state-of-the-art spatial metrics, SPAtial EFficiency, fractions skill score, Goodman–Kruskal's lambda, Cramer's V, Mapcurves, and Kling–Gupta efficiency, for the period 1961–2005. The multi-model ensemble (MME) precipitation and maximum and minimum temperature data were generated through the intelligent merging of simulated precipitation and maximum and minimum temperature of selected GCMs employing random forest (RF) regression and simple mean (SM) techniques. The results indicated some differences in the ranks of GCMs for different spatial metrics. The overall ranks indicated NorESM1-M, MIROC5, BCC-CSM1-1, and ACCESS1-3 as the best GCMs in simulating the spatial patterns of mean annual, monsoon, winter, pre-monsoon, and post-monsoon precipitation and maximum and minimum temperature over Pakistan. MME precipitation and maximum and minimum temperature generated based on the best-performing GCMs showed more similarities with observed precipitation and maximum and minimum temperature compared to precipitation and maximum and minimum temperature simulated by individual GCMs. The MMEs developed using RF displayed better performance than the MMEs based on SM. Multiple spatial metrics have been used for the first time for selecting GCMs based on their capability to mimic the spatial patterns of annual and seasonal precipitation and maximum and minimum temperature. The approach proposed in the present study can be extended to any number of GCMs and climate variables and applicable to any region for the suitable selection of an ensemble of GCMs to reduce uncertainties in climate projections.

Materials Specificity and Directed Assembly of a Gold‐Binding Peptide

Abstract: Adsorption studies of a genetically engineered gold-binding peptide, GBP1, were carried out using a quartz-crystal microbalance (QCM) to quantify its molecular affinity to noble metals. The peptide showed higher adsorption onto and lower desorption from a gold surface compared to a platinum substrate. The material specificity, that is, the preferential adsorption, of GBP1 was also demonstrated using gold and platinum micropatterned on a silicon wafer containing native oxide. The biotinylated three-repeat units of GBP1 were preferentially adsorbed onto gold regions delineated using streptavidin-conjugated quantum dots (SAQDs). These experiments not only demonstrate that an inorganic-binding peptide could preferentially adsorb onto a metal (Au) rather than an oxide (SiO2) but also onto one noble metal (Au) over another (Pt). This result shows the utility of an engineered peptide as a molecular erector in the directed immobilization of a nanoscale hybrid entity (SAQDs) over selected regions (Au) on a fairly complex substrate (Au and Pt micropatterned regions on silica). The selective and controlled adsorption of inorganic-binding peptides may have significant implications in nano- and nanobiotechnology, where they could be genetically tailored for specific use in the development of self-assembled molecular systems.

Characteristics and wear performance of borided Ti6Al4V alloy

Abstract: In this study, a 10 µm thick uniform boride layer, composed of TiB 2 and TiB phases, was formed on the surface of a Ti6Al4V alloy using a pack boriding technique. The hardness of the boride layer was over 2000 HV. Beneath the boride layer, a boron diffusion zone (BDZ) appeared with a thickness of about 50 µm. The microstructure of the BDZ was composed of randomly oriented TiB whiskers mixed with the structure of the base metal. In the BDZ, hardness decreased gradually towards the base metal owing to the reduction of the TiB volume fraction. The borided alloy exhibited excellent wear resistance along with a lower coefficient of friction against sapphire ball under both dry and smear lubricated sliding conditions when compared to the as-received state.