Characterization of Microstructural and Morphological Properties in As-deposited Ta/NiFe/IrMn/CoFe/Ta Multilayer System

Surface morphology and its relationship with microstructure in Ta/NiFe/IrMn/CoFe/Ta multilayer system deposited by pulsed DC magnetron sputtering have been investigated in dependence of Ta buffer and NiFe seed layer thicknesses using atomic force microscopy.The structural parameters such as grain size,dislocation density,texture and strain were calculated.For each surface,a self-affinity behavior with mean fractal dimensions in the range of 2.03-2.18 was found.Additionally,it was also observed that the surface of all samples has locally smooth textured surface structure in the short range.The texture aspect parameter and texture direction index have been obtained for isotropy/anisotropy surface texture.A significant relationship between the surface texture and the strength of the〈111〉texture in IrMn layer has been found.The analysis indicated that the surface roughness is strongly affected by the thicknesses of the NiFe seed and Ta buffer layers.     

Enzymatic Construction of Artificial Base Pairs: The Effect of Metal Shielding

Th formation of metal base pairs is a versatile method for the introduction of metal cations into nucleic acids that has been used in numerous applications including the construction of metal nanowires, development of energy, charge-transfer devices and expansion of the genetic alphabet. As an alternative, enzymatic construction of metal base pairs is an alluring strategy that grants access to longer sequences and offers the possibility of using such unnatural base pairs (UBPs) in SELEX experiments for the identification of functional nucleic acids. This method remains rather underexplored, and a better understanding of the key parameters in the design of efficient nucleotides is required. We have investigated the effect of methylation of the imidazole nucleoside ( dIm ^{n Me} TP ) on the efficiency of the enzymatic construction of metal base pairs. The presence of methyl substituents on dImTP facilitates the polymerase-driven formation of dIm^4Me −Ag^I− dIm and dIm^2MeTP −Cr^III− dIm base pairs. Steric factors rather than the basicity of the imidazole nucleobase appear to govern the enzymatic formation of such metal base pairs. We also demonstrate the compatibility of other metal cations rarely considered in the construction of artificial metal bases by enzymatic DNA synthesis under both primer extension reaction and PCR conditions. These findings open up new directions for the design of nucleotide analogues for the development of metal base pairs.     

Adaptive Information Coding for Secure and Reliable Wireless Telesurgery Communications

Telesurgical Robot Systems (TRSs) have been the focus of research in academic, military, and commercial domains for many years. Contemporary TRSs address mission critical operations emerging in extreme fields such as battlefields, underwater, and disaster territories. The lack of wirelined communication infrastructure in such fields makes the use of wireless technologies including satellite and ad-hoc networks inevitable. TRSs over wireless environments pose unique challenges such as preserving a certain reliability threshold, adhering some maximum tolerable delay, and providing various security measures depending on the nature of the operation and communication environment. In this study, we present a novel approach that uses information coding to integrate both light-weight privacy and adaptive reliability in a single protocol called Secure and Statistically Reliable UDP (SSR-UDP). We prove that the offered security is equivalent to the existing AES-based long key crypto systems, yet, with significantly less computational overhead. Additionally, we demonstrate that the proposed scheme can meet high reliability and delay requirements of TRS applications in highly lossy environments while optimizing the bandwidth use. Our proposed SSR-UDP protocol can also be utilized in similar cyber-physical wireless application domains.     

Emulsion copolymerization of vinyl acetate and 2‐ethyl hexyl acrylate using nonionic emulsifiers in loop reactor

Batch emulsion copolymerization of vinyl acetate and 2‐ethyl hexyl acrylate (VAc/2EHA = 90 : 10) was initiated by the thermal initiators ammonium persulfate and potassium persulfate at 70°C in the presence of nonylphenol ethoxylates with varying chain lengths and poly(vinyl alcohol). VAc–2EHA copolymer latexes were synthesized as two different series in a loop reactor. The first series was initiated by ammonium persulfate, and the second series was initiated by potassium persulfate. The influence of the counterions or initiators and chain lengths of a nonionic emulsifier on the properties of VAc–2EHA copolymer latexes were determined by measuring the viscosities, weight‐average molecular weights, number‐average molecular weights, molecular weight distribution, and surface tension of latexes to air. The results for the copolymer latexes indicated that some of their physicochemical properties increased with increasing chain length of the nonionic emulsifier, but some of them followed a different trend for the two initiators. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1380–1384, 2005     

Synthesis of 2‐(9H‐carbazole‐9‐yl)ethyl methacrylate: Electrochemical impedance spectroscopic study of poly(2‐(9H‐carbazole‐9‐yl)ethyl methacrylate) on carbon fiber

In this contribution, 2‐(9H‐carbazol‐9‐yl) ethyl methacrylate (CzEMA) monomer was chemically synthesized. The monomer characterization was performed by FT‐IR, ¹H‐NMR, ¹³C‐NMR, and melting point analysis. The electropolymerization of CzEMA was studied onto carbon fiber microelectrodes (CFMEs) as an active electrode material in 0.1M sodium perchlorate (NaClO₄)/acetonitrile (ACN) solution. The electropolymerization experiments were done from 1 mM to 10 mM. The detailed characterization of the resulting electrocoated Poly (CzEMA)/CFME thin films was studied by various techniques, i.e., cyclic voltammetry (CV), Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The effects of initial monomer concentrations (1, 3, 5, and 10 mM) during the preparation of modified electrodes were examined by EIS. Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode‐magnitude, and Bode‐phase plots. Variation of capacitance values by initial monomer concentration and specific capacitance values are presented. The highest specific capacitance value electrocoated polymer thin film by CV method in the initial monomer concentration of 5 mM with a charge of 52.74 mC was obtained about 424.1 μF cm^?2. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface Morphology, Structural and Magnetic Properties of Electrodeposited NiFeCu/Cu Films

The magnetic and structural properties of the NiFeCu/Cu films electrodeposited on polycrystalline titanium (Ti) substrates and their characterizations were studied. The structural analysis by X-ray diffraction (XRD) has revealed that all films have face-centred cubic (FCC) structure. On the other hand, the XRD analysis showed that the degree of (111) texture is dependent on the Cu content within the film. The composition analysis was carried out by energy-dispersive X-ray spectroscopy (EDX). The result of EDX indicated that the Cu content within the film increases with increasing of non-magnetic Cu layer thickness. The hysteresis loops of the films measured by vibrating sample magnetometer (VSM) showed that all films have a small coercivity typical for soft magnetic materials. The surface morphological structure of the films was investigated by atomic force microscopy (AFM). AFM images indicated that all films have main grains (globular islands) and smaller secondary grains on the main grains with different sizes. The differences observed in the magnetic properties of the films were attributed to the Cu content within the films.     

Morphological and impedance studies on electropolymerized 3,4-(2,2-dibenzylpropylenedioxy)thiophene nanostructures on micron sized single carbon fiber

Micron sized single carbon fibers were cyclovoltammetrically coated with poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] resulting in a nanofiber network at the surface. The method provides conjugated polymer nanostructures covalently and uniformly bound to micron sized substrates. When the electropolymerization is carried out with different electrolytes in acetonitrile the dopant influences the structure of the coating layer what is proved by electrochemical impedance spectroscopy and electron microscopy. Electrodes based on poly[3,4-(2,2-dibenzylpropylenedioxy)thiophene] on single carbon fiber microelectrodes (SCFMEs) prepared in Bu₄NPF₆/ACN show the best capacitance performance due to their higher surface area. The improvement is attributed to the formed nanofiber network structure which results in a more efficient charge transport and collection.     

Mathematical modeling of multiple-effect evaporators and energy economy

In this study, a mathematical model was developed for multiple-effect evaporators. These evaporators have cocurrent, countercurrent and parallel flow operation options. Each operation was investigated with and without pre-heaters. The effect of pre-heating on evaporation process was investigated from the point of energy economy. A sugar factory's data was used with the applied models as a case study. The results obtained for pre-heated and non-pre-heated situations were compared with each other. The maximum COP is found as 3.33 for countercurrent operation with pre-heating. The minimum COP is 2.57 for parallel flow operation without pre-heating.