A Multi-Objective Mathematical Programming Model for Transit Network Design and Frequency Setting Problem

İbrahim AKGÜN

In this study, we propose a novel multi-objective nonlinear mixed-integer mathematical programming model for the transit network design and frequency setting problem that aims at designing the routes and determining the frequencies of the routes to satisfy passenger demand in a transit network. The proposed model incorporates the features of real-life transit network systems and reflects the views of both passengers and the transit agency by considering the in-vehicle travel time, transfers, waiting times at the boarding and transfer stops, overcrowding and under-utilization of vehicles, and v ...More

Eco-Friendly Synthesis of Silver Nanoparticles Using Pulsed Plasma in Liquid: Effect of Surfactants

Emil ÖMÜRZAK

Silver (Ag) nanoparticles were successfully prepared by using the in-liquid pulsed plasma technique. This method is based on a low voltage, pulsed spark discharge in a dielectric liquid. We explore the effect of the protecting ligands, specifically Cetyl Trimethylammonium Bromide (CTAB), Polyvinylpyrrolidone (PVP), and Sodium n-Dodecyl Sulphate (SDS), used as surfactant materials to prevent nanoparticle aggregation. The X-Ray Diffraction (XRD) patterns of the samples confirm the face-centered cubic crystalline structure of Ag nanoparticles with the presence of Ag2O skin. Scanning Transmission ...More

Multi-Directional Cloak Design by All-Dielectric Unit-Cell Optimized Structure

Mirbek TURDUEV

In this manuscript, we demonstrate the design and experimental proof of an optical cloaking structure that multi-directionally conceals a perfectly electric conductor (PEC) object from an incident plane wave. The dielectric modulation around the highly reflective scattering PEC object is determined by an optimization process for multi-directional cloaking purposes. Additionally, to obtain the multi-directional effect of the cloaking structure, an optimized slice is mirror symmetrized through a radial perimeter. The three-dimensional (3D) finite-difference time-domain method is integrated with ...More

Erratum: On the Temporal Stability of Analyte Recognition with an E-Nose Based on a Metal Oxide Sensor in Practical Applications (vol 18, 550, 2018)

Ruslan ADİL AKAY TEGİN | Camilya SMANALİYEVA | Coşkan ILICALI

On the Temporal Stability of Analyte Recognition with an E-Nose Based on a Metal Oxide Sensor in Practical Applications

Ruslan ADİL AKAY TEGİN | Camilya SMANALİYEVA | Coşkan ILICALI

The paper deals with a functional instability of electronic nose (e-nose) units which significantly limits their real-life applications. Here we demonstrate how to approach this issue with example of an e-nose based on a metal oxide sensor array developed at the Karlsruhe Institute of Technology (Germany). We consider the instability of e-nose operation at different time scales ranging from minutes to many years. To test the e-nose we employ open-air and headspace sampling of analyte odors. The multivariate recognition algorithm to process the multisensor array signals is based on the linear d ...More

Toxicity of Zn-Fe Layered Double Hydroxide to Different Organisms in the Aquatic Environment

Mehmet KOBYA

The application of layered double hydroxide (LDH) nanomaterials as catalysts has attracted great interest due to their unique structural features. It also triggered the need to study their fate and behavior in the aquatic environment. In the present study, Zn-Fe nanolayered double hydroxides (Zn-Fe LDHs) were synthesized using a co-precipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and nitrogen adsorption-desorption analyses. The toxicity of the home-made Zn-Fe LDHs catalyst was examined by emp ...More

Novel CNT Supported Molybdenum Catalyst for Detection of L-Cysteine in Its Natural Environment

Nahit AKTAŞ

In this study, novel carbon nanotube-supported Mo (Mo/CNT) catalysts were prepared with the sodium borohydride reduction method for the detection of L-cysteine (L-Cys, L-C). Mo/CNT catalysts were characterized with scanning electron microscopy with elemental dispersion X-ray (EDX-SEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectrometry (UV-vis), temperature-programmed reduction (TPR), temperature programmed oxidation (TPO), and temperature-programmed desorption (TPD) techniques. The results of these advanced surface characterization techniques revealed that the catalysts were pre ...More

Alternative Bioremediation Agents against Haloacids, Haloacetates and Chlorpyrifos Using Novel Halogen-Degrading Bacterial Isolates from the Hypersaline Lake Tuz

Yılmaz KAYA

The indiscriminate use of chemical pesticides alongside the expansion of large-scale industries globally can critically jeopardize marine ecology and the well-being of mankind. This is because the agricultural runoffs and industrial effluents eventually enter waterways before flowing into highly saline environments i.e., oceans. Herein, the study assessed two novel bacterial isolates,Bacillus subtilisstrain H1 andBacillus thuringiensisstrain H2 from the hypersaline Lake Tuz in Turkey to degrade recalcitrant haloalkanoic acids, haloacetates and chlorpyrifos, and consequently, identify their opt ...More