Object-based road extraction from satellite images using ant colony optimization

Increasing demands for up-to-date road network and the availability of very-high-resolution (VHR) satellite images as well as the popularity of high-speed computers provide motivation and preliminary materials for researchers to propose more advanced approaches in order to increase the automation and robustness of road extraction strategies. In this article, road characteristics are modelled via object-based image analysis (OBIA). Object-based information is embedded as heuristic information in the ant colony optimization (ACO) algorithm for handling the road network extraction problem. A new neighbourhood definition in object space is introduced, which affects the transition rule in order to decrease the road gaps. Furthermore, an innovative desirability function for ACO is designed, which extracts the road objects, competently. The experimental results demonstrate the efficiency of the proposed algorithm for road extraction from VHR images. Moreover, the results of two state-of-the-art methods are compared with the proposed algorithm.     

Effect of Deep Cryogenic Heat Treatment on the Wear Behavior of Carburized DIN 1.7131 Grade Steel

The effects of the deep cryogenic heat treatment on the microstructural changes,wear resistance,and hardness of carburized DIN 1.7131 grade steel were investigated.Results show that cryogenic heat treatment reduced the retained austenite and increased the carbide amount.In addition,after the cryogenic heat treatment,carbide shows a more uniform distribution,as compared to the conventionally treated ones.It was also clarified that the hardness of the cryogenically treated samples was improved,but the relative improvement decreases with the distance as the surface increases.It has been shown that the wear resistance improves due to the cryogenic heat treatment,and the predominant wear mechanism is a combination of the adhesive and tribo-chemical wear.     

Natural vs. Synthetic Phosphate as Efficient Heterogeneous Compounds for Synthesis of Quinoxalines

Natural phosphate (NP) and synthetic fluorapatite phosphate (SFAP) were proposed as stable, inexpensive, readily available and recyclable catalysts for the condensation of 1,2-diamines with 1,2-dicarbonyls in methanol to afford quinoxaline at room temperature. NP provided as high as 92–99% yield for quinoxalines in short reaction times (i.e., 1–45 min), while SFAP created quinoxalines with 87–97% yield in 60–120 min. From the chemical analyses, X-ray fluoresecency, X-ray diffraction, energy dispersive X-ray and Fourier-transform infrared spectroscopy methods, two main phases (CaO, P₂O₅) appeared in NP together with other low content phases (SiO₂, Fe₂O₃). Compared to other phases, apatite (CaO and P₂O₅ as Ca10(PO₄)₆) played a major role in the catalytic activity of NP. SFAP with similar Ca/P atomic ratio showed a relatively lower catalytic activity than NP for the condensation of 1,2-diamine with 1,2-dicarbonyl in methanol at ambient temperature. To investigate the recyclability of catalysts, the surface properties of NP and 6-recycled NP were investigated using scanning electron microscopy, energy dispersive X-ray and Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods. Some differences were observed in NP and 6-recycled NP’s particle size, surface area, the volume and size of pores, and the content of elements; nevertheless, the use–reuse process did not noticeably change the catalytic property of NP.     

Experimental and Numerical Simulation of Dry Pressure Drop in High‐Capacity Structured Packings

Experimental and numerical studies were conducted on the performance and capacity of structured packings for mixture separation with very low separation factor. Different formations and conditions of the innovative structured packing PACK‐2100 with high surface area were studied to evaluate the main characteristics such as dry pressure drop. In addition, numerical simulation was performed to describe the details of the flow structure in these modified structured packings. Three‐dimensional computational fluid dynamics modeling of PACK‐2100 allowed for comparing the pressure drop in both laminar and turbulent flow regime. The obtained experimental and numerical data demonstrate the potential contribution of the packing to high‐efficiency systems with low separation factor.     

Synthesis and characterization of novel aromatic polyamides bearing CF3, quinoxaline‐anthraquinone pendants: Study of photophysical and electrochemical properties by using nanocomposite electrode paste

A new aromatic diamine, 2,3‐bis(4‐(4‐amino‐2‐(trifluoromethyl) phenoxy)phenyl)naphtho[2,3‐f]quinoxaline‐7,12‐dione, was synthesized and fully characterized by using FTIR, ¹H and ¹³C NMR, DEPT technique, and elemental analysis. A series of novel fluorescent anthraquinone‐quinoxaline containing polyamides (PAs) with inherent viscosities of 0.39–0.62 dL/g was prepared by direct polycondensation of the diamine with various dicarboxylic acids. These PAs were readily soluble in many polar aprotic organic solvents and could be solution‐cast into tough and flexible films. The PAs exhibited glass transition temperatures (T_g)s between 230 and 323°C, and 10% weight loss temperatures in the range of 362–433°C in N₂. All of the PAs have fluorescence emission in solution and in solid state with maxima around 452–510 nm and with the quantum yields in the range of 6–17%. Also, cyclic voltammetry (CV) method was used to study the electrochemical oxidation behavior of these polymers at the surface of a modified multiwalled carbon nanotube (MWCNT)s glassy electrode. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and Structural Characterization of Three New Tetraorganodistannoxanes

An efficient method was developed for the preparation of three tetraorganodistannoxane complexes, (C₂H₅)₈Sn₄Cl₂(CH₃O)₂O₂ (1), (CH₃)₈Sn₄(C₃H₄N₃S)₂(CH₃O)₂O₂ (2) and (C₄H₉)₈Sn₄(C₃H₄N₃S)₂(CH₃O)₂O₂ (3). All prepared complexes were characterized by infrared, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopes and elemental analysis. The molecular structure of a representative complex (1) was determined by single-crystal X-ray diffraction. Results showed that 1 is a tetranuclear, centrosymmetric dimeric, and contains two endo-cyclic five-coordinated tin atoms and two exo-cyclic five-coordinated tin atoms. Compound 1 lies about a center of inversion and the tetranuclear molecule features a three-ring-staircase Sn₄O₄ core. The asymmetric unit of 1 contains two independent Sn(IV) atoms and a 2D infinite rigid chain structure forms via C–H···Cl interactions between tetranuclear units.     

Preparation of SnO2 Nanoparticles from a New Tin(IV) Complex: Spectroscopic and Photoluminescence Studies

A new dimethyltin(IV) complex, {[Me₂Sn(O₂CNC₉H₆)]₂O}₂ (1), was prepared by reaction of dimethyltin(IV) dichloride with the quinoline-2-carboxylic acid and characterized by elemental analysis, IR, ¹H-, ¹³C-, ¹¹⁹Sn-NMR spectroscopes. The structure of 1 was determined by single-crystal X-ray diffraction. The results showed that 1 is a tetranuclear, centrosymmetric dimeric, and contains two endo-cyclic five-coordinated and two exo-cyclic six-coordinated tin atoms and a N-atom of the 2-quinaldic carboxylate ligand coordinated to exo-cyclic tin. Complex 1 was utilized as a precursor for SnO₂ nanoparticles by direct thermal decomposition at 500 °C in air. The nano-structure of SnO₂ was characterized by scanning electron microscopy and X-ray powder diffraction. The SnO₂ core showed a band gap of ~4 eV determined from the UV/visible absorption spectrum. The SnO₂ nanoparticles show stable photoluminescence (PL) with an emission centered at 557 nm.     

Functional Nucleic Acids Under Unusual Conditions

Functional nucleic acids (FNAs), including naturally occurring ribozymes and riboswitches as well as artificially created DNAzymes and aptamers, have been popular molecular toolboxes for diverse applications. Given the high chemical stability of nucleic acids and their ability to fold into diverse sequence-dependent structures, FNAs are suggested to be highly functional under unusual reaction conditions. This review will examine the progress of research on FNAs under conditions of low pH, high temperature, freezing conditions, and the inclusion of organic solvents and denaturants that are known to disrupt nucleic acid structures. The FNA species to be discussed include ribozymes, riboswitches, G-quadruplex-based peroxidase mimicking DNAzymes, RNA-cleaving DNAzymes, and aptamers. Research within this space has not only revealed the hidden talents of FNAs but has also laid important groundwork for pursuing these intriguing functional macromolecules for unique applications.     

Synthesis and Mechanical Properties of Fully Dense Ti2SC

Because the layered machinable ternary carbide, Ti₂SC, has a significantly shorter c -lattice parameter—as compared with most of the 50+ other so-called M_n+1AX_n (MAX) phase family (M=early transition metal; A=A group element and X=C or N and n=1–3) to which it belongs—it was postulated that its mechanical properties would be significantly different than the other MAX phases. In this work, fine-grained (FG) and coarse-grained (CG) polycrystalline fully dense Ti₂SC samples were fabricated. Hot pressing Ti₂SC powders, at 1500°C under a stress of ∼45 MPa for 5 h resulted in FG (2–4 μm) samples which and upon further annealing for 20 h at 1600°C resulted in CG (10–20 μm) ones. No peaks other than those associated with Ti₂SC and an impurity anatase phase, with a volume fraction of ∼6 vol% were observed in the XRD patterns and micrographs. The average Vickers hardness in the 2–300 N range is 8±2 GPa with the FG samples being slightly harder. This hardness is the highest of any of the MAX phases characterized to date. Also in contrast to all MAX phases, cracks extended from the corners of Vickers indents in the FG samples. From these cracks the fracture toughness was estimated and found to increase more or less linearly with load from ≈4 to 6 MPa·m^1/2 as the Vickers force was increased from 50 to 300 N, respectively. The room temperature compressive stress of the FG samples was 1.4±0.2 GPa; the failure mode was brittle. Its Young's modulus—also one of the highest for a M₂AX phase measured to date—was 316±2 GPa. There was no evidence for incipient kink band formation during simple compression. The latter is attributed, in part, to the fine grain size of the hot-pressed material.