Mechanical and microstructural properties of low-carbon steel-plate-reinforced gray cast iron

In the present experimental study, strengthening of gray cast iron by reinforcing with steel plates was investigated in the as-cast and normalized conditions. Normalizing heat treatments were applied to the specimens at temperatures of 800 °C and 850 °C. Three-point bend specimens were manufactured from gray cast iron and also from gray cast iron with reinforced steel plates. Flexural strengths of the steel-plate-reinforced cast iron were calculated for four distinct volume fractions (V_r = 0.04, 0.08, 0.12, and 0.16). The current study shows that the steel-plate-reinforced gray cast iron has higher flexural strength and flexural modulus than the cast iron without reinforcement. The flexural strength considerably increases with slight increase in normalization temperature. Optical and scanning electron microscopy analyses were used to examine flake morphology and microstructures of gray cast iron and steel-plate-reinforced gray cast iron. It is noted that carbon diffuses from the gray cast iron to the steel plates. A transition region containing partially dissolved graphite and having high hardness was observed due to the carbon diffusion.     

Seismic microzonation of the historic peninsula of İstanbul

In this study, the geological and geotechnical conditions of old Istanbul (Fatih and Eminönü provinces) were investigated in detail and a seismic microzonation study was undertaken for this historical peninsula, which is the site of many ancient structures. Dynamic site response, liquefaction potential and slope stability analyses were carried out, based on field and laboratory tests and earthquake time histories computed with respect to probabilities of exceedance of 10 and 40% in 50 years. The output data obtained from the analyses were evaluated by GIS techniques, and ground shaking, liquefaction susceptibility and landslide hazard maps were prepared.     

Neural network and fuzzy logic-based hybrid attitude controller designs of a fixed-wing UAV

Neural Computing and Applications - In this paper, a mini unmanned aerial vehicle (UAV) is planned to be used in applications such as spraying pesticide and weed control in agricultural areas....     

Atmospheric and anthropogenic deterioration of the İvriz rock monument: Ereğli-Konya,Central Anatolia,Turkey

Bulletin of Engineering Geology and the Environment - The aim of this study is to determine the extent of deterioration of the limestone on which the İvriz rock monument is engraved. This...     

Model Predictive Control Coupled with Artificial Intelligence for Eddy Current Dynamometers

The recent studies on Artificial Intelligence (AI) accompanied by enhanced computing capabilities supports increasing attention into traditional control methods coupled with AI learning methods in an attempt to bringing adaptiveness and fast responding features. The Model Predictive Control (MPC) technique is a widely used, safe and reliable control method based on constraints. On the other hand, the Eddy Current dynamometers are highly nonlinear braking systems whose performance parameters are related to many processes related variables. This study is based on an adaptive model predictive control that utilizes selected AI methods. The presented approach presents an updated the mathematical model of an Eddy Current Dynamometer based on experimentally obtained system operational data. Finally, the comparison of AI methods and related learning performances based on the assessment technique of mean absolute percentage error (MAPE) issues are discussed. The results indicate that Single Hidden Layer Neural Network (SHLNN), General Regression Neural Network (GRNN), Radial Basis Network (RBNN), Neuro Fuzzy Network (ANFIS) coupled MPC have quite satisfying performances. The presented results indicate that, amongst them, GRNN appears to provide the best performance.     

Increasing the conversion fraction of sulfur to sodium thiosulfate with the ultrasound energy

The usage of ultrasound has gained popularity in the recent years. Ultrasonic processing means blasting liquids, usually water, with very intense sound at high frequency, producing very well mixed powerful chemical and physical reactions. This paper deals with the investigation of the effect of ultrasonic energy on the conversion fraction of sulfur in the production reaction of sodium thiosulfate which was obtained from sulfur and Na₂SO₃ solution. Concentration of Na₂SO₃ solution parameter was chosen as the constant parameter. The experiments were performed with various amplitudes of ultrasound power and in the absence and presence of ultrasound energy in various temperatures with various particle sizes. The results indicate that the conversion fraction values increase in the presence of ultrasound energy and increase at high amplitude values.     

Palladium-Catalyzed Suzuki–Miyaura Reaction Using Saturated N-Heterocarbene Ligands

Recent studies have pointed to the heptamethylbenzenium cation as a prominent intermediate in the methanol to hydrocarbons (MTH) reaction. The reactions of the heptamethylbenzenium cation in a H-beta zeolite was studied at 300 °C by feeding its corresponding base (WHSV = 0.4 h^?1). The reactant was converted completely into aliphatic products, polymethylbenzenes and coke under the employed conditions. The results testify that the proposed reaction intermediate yields the same product spectrum as methanol. The composition of the material retained in the catalyst micropores after 15 min of reaction was determined by dissolving the catalyst in 15% HF. Polymethylated benzenes (predominantly pentamethylbenzene), dihydro-trimethylnaphthalenes, and hexamethylnaphthalene were the major components. The results also support the idea that the lowest naphthalene derivative is formed from the heptamethylbenzenium cation by a molecular rearrangement. Hence, the heptamethylbenzenium cation is inherently linked to both product formation and catalyst deactivation in the MTH reaction.     

Realizations of mutative 4-ports and their applications to memstor simulations

In this paper, in addition to the universal 4-port mutator circuit introduced earlier with an adder and a subtractor block, two more 4-port mutator circuits, one with plus type (CCII+) and minus type current conveyors (CCII?), the other with a plus type current conveyor (CCII+) and one minus type current follower (CF?) are presented, their port relation matrix and their realization of different memstors are tabulated. How the transfer characteristics of the ideal mutative 4-ports with respect to frequency hold is verified using their transistor level simulations. By terminating properly two ports of the mutative 4-port simulations of a memristor with three different mutators, of a meminductor and of a memcapacitor are presented and compared also with some mutators existing in the literature.     

Measurements of the total molecular differential attenuation coefficients of some compounds for scattering of γ-rays

The differential attenuation coefficients for total scattering have been measured using the Si(Li) detector at photon excitation energy of 59.5 keV for Fe₂O₃, Y₂O₃, Nb₂O₅, SeO₂, Sb₂O₅ and BaO compounds at seven angles ranging from 60° to 120° at intervals of 10°. The obtained results have been compared with relativistic and non-relativistic theoretical values.     

Current Urban Discourse,Urban Transformation and Gentrification in Istanbul

In the mid-2000s, unprecedented economic growth provided a catalyst for Istanbul's transformation. Tolga İslam outlines the background to large-scale urban development and renewal projects that have been undertaken by local authorities throughout the city. Copyright © 2010 John Wiley & Sons, Ltd.