Warfarin improves the outcome of infrainguinal vein bypass grafting at high risk for failure

An economic evaluation of energy-absorbing flooring designed to prevent hip fractures revealed a payback period of 10 1/2 years if only direct costs avoided were evaluated and just over 11 months when direct and indirect costs were included. Cost-effectiveness ratios of less than $0 per hip fracture prevented and life year saved were also estimated.     

Geostatistical Simulation Study of Porosity and Hydrocarbon Saturation Values in the Vicinity of Adiyaman, Turkey

The Cretaceous Mardin Group sequence in the Adiyaman region displays a “continental platform type” petroleum system. The main lithologies within the sequence are shales, mudstones, and carbonates. Most dolomitic and bioclastic wackestones of the Karababa-C member and dolomites of the Derdere Formation have hydrocarbon reservoir characteristics, whereas shales and some carbonates of the Derdere and Karababa-A member have mature hydrocarbon source-rock properties. To determine the porosity and hydrocarbon saturation value vs. depth and areal extends, geostatistical simulation for the three dimensional evaluation of the study area were constructed and the variogram functions were calculated and then three dimensional variograms which were obtained from the porosity and hydrocarbon saturation values were modelled spherically. According to the simulation results, the porosity values in the Karababa-C member decrease with increasing depth. The amount of hydrocarbon saturation tends to decrease with increasing depth, as well and the decrease ratio is 7.2%. The suitability of the model parameters were validated with back-kriging technique.     

Effect of Deposition Time on Properties of Ni–Cu Alloy Films Electrodeposited on ITO Coated Glass Substrates

The structural, magnetic, and surface morphological properties of Ni–Cu films electrodeposited on ITO (indium tin oxide) glass substrates at different deposition times ranging between 2 s and 600 s have been investigated. The structure of the films was studied using X-ray Diffraction (XRD). The XRD results showed that all samples have a face-centered cubic (FCC) structure. From the XRD patterns, it was also found that the crystallographic structure of the films strongly depends on the deposition time. Compositional analysis of Ni–Cu films carried out by energy dispersive X-ray spectroscopy (EDX) indicated that the Ni content within the films increases with increasing deposition time and then almost saturates at deposition time of 600 s. The result of the vibrating sample magnetometer (VSM) measurements revealed that the saturation magnetization increases with increasing Ni content within the film. Atomic force microscopy (AFM) was used to study the topographic properties of Ni–Cu films. It was found that the surface roughness of Ni–Cu alloy films increases with increasing deposition time. Furthermore, the surface texture was found to be isotropic for all films grown at different deposition times.     

A novel EDOT–nonylbithiazole–EDOT based comonomer as an active electrode material for supercapacitor applications

A novel EDOT–nonylbithiazole–EDOT based bis(3,4-ethylene-dioxythiophene)-(4,4′-dinonyl-2,2′-bithiazole) comonomer was synthesized and was electrochemically deposited onto carbon fiber electrode as an active electrode material. An electrochemical impedance study on the prepared electrodes is reported in this paper. Capacitive behavior of the carbon fiber microelectrode/poly(3,4-ethylene-dioxythiophene)-(4,4′-dinonyl-2,2′-bithiazole) system was investigated with cyclic voltammetry (CV) experiments and electrochemical impedance spectroscopy. Variation of capacitance values by scan rate and specific capacitance values at different potentials are presented. Specific capacitance value for a galvanostatically prepared polymer film with a charge of 5 C cm⁻² was obtained about 340 mF cm⁻². Effect of the solvent and the deposition charge on the capacitive behavior of the film was investigated using electrochemical impedance spectroscopy. An equivalent circuit model was proposed and the electrochemical impedance data were fitted to find out numerical values of the proposed components. The galvanostatic charge/discharge characteristic of a film was investigated by chronopotentiometry and the morphology of the films electrodeposited at different deposition charges were monitored using FE-SEM.     

Experimental characterization of the impact‐damage tolerance of a cross‐ply graphite‐fiber/epoxy laminate

In this study, the impact‐damage tolerance of a graphite‐fiber/epoxy composite laminate is studied by examining the correlation between the impact force and the resulting delamination area in the laminate. The cross‐ply [0₂/90₂/0₂]_s composite laminate was made of thermosetting P7051S‐20Q‐1000 prepregs (Toray Composites America). A Hopkinson pressure bar (HPB) was employed to create the impulsive loading with varying magnitude. Transient impact force, displacement, impact power, and transmitted impact energy were calculated using the transient signals recorded from the strain gage mounted on the HPB. Impulsive loads with controllable magnitude were used to induce delamination damage with varying size in the composite samples. Nondestructive evaluation based on a novel ultrasonic pulse‐echo reflector technique was used successfully for characterizing the delamination areas in the thin composite samples with thickness ∼2 mm. The present experimental results indicate that there exists a very good linear correlation between the impact force (e.g. the peak force, impact impulse, peak impact power, and the transmitted impact energy of the first impact force pulse exerted by the HPB) and the delamination area of the composite samples. This correlation can be used to determine the threshold of the impact force that initiates the delamination damage in the composite laminate. In contrast to the weight‐drop test, the present experimental method successfully examined the impact damage tolerance of polymer matrix composites (PMCs) subjected to impulsive loading with very high force magnitude and ultra short duration such as the typical ballistic impact. The present method and results can be used for the study of impact damage tolerance of PMCs with varying lay‐ups and interface modifications. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Nano-engineering of high-performance PA6.6 nanocomposites by the integration of CVD-grown carbon fiber on graphene as a bicomponent reinforcement by melt-compounding

In this study, long carbon nanofibers (CNFs) were grown on graphene nanoplatelets (GNPs) by chemical vapor deposition (CVD) technique to develop three-dimensional (3D) bicomponent nanostructures. The structure and properties of graphene before and after CVD process were investigated in details. X-ray photoelectron analysis depicted the formation of Fe-C bonds by the deposition of carbon atoms on the catalyst surface of Fe₂O₃. This hybrid additive was firstly used as a reinforcing agent in melt compounding to fabricate PA6.6-based nanocomposites with enhanced mechanical and thermal properties. Both GNP and CNF-GNP have enough surface oxygen functional groups to improve the interfacial interactions with polyamide matrix and thus provide good wettability. Also, both neat GNP and its bicomponent additive with CNF also acted as a nucleating agent and allowed the crystal growth in nanocomposite structure. Homogeneous dispersion of nanoparticles was achieved by using thermokinetic mixer during compounding by applying high shear rates. Mechanical results showed that 23 and 34% improvement in flexural and tensile modulus values, respectively, was attained by the addition of 0.5 wt % CNF-GNP hybrid additive. The heat distortion temperature and Vicat softening temperature of the resulting PA6.6 nanocomposites were improved compared to neat PA6.6 material indicating performance enhancement at higher service temperature conditions. CNF was successfully grown on Fe-loaded GNP by CVD method and this hybrid additive was compounded with PA6.6 by melt-mixing process. Mechanical results showed that 34% improvement in tensile modulus value was attained by the addition of 0.5 wt % CNF-GNP hybrid additive because it acted as a nucleating agent and allowed the crystal growth in the nanocomposite structure. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48347.     

Deposition potential dependence of composition, microstructure, and surface morphology of electrodeposited Ni–Cu alloy films

Composition, microstructure, and surface morphology of Ni–Cu alloy films electrodeposited at different deposition potentials have been investigated. The microstructural analysis carried out by using X-ray diffraction (XRD) confirmed that all Ni–Cu films are polycrystalline in nature and possess face-centered cubic structure. XRD analysis also revealed that the (111) peak of the Ni–Cu alloy films splits into two as Cu-rich and Ni-rich peaks and the peak intensities change depending on the deposition potential and hence the film composition. Compositional analysis of Ni–Cu films carried out by energy dispersive X-ray spectroscopy showed that Ni content within the films increases as the deposition potential becomes more negative. The morphological analysis performed by using a scanning electron microscopy and an atomic force microscopy revealed that the surface morphology changes significantly with applied deposition potential. Furthermore, a direct correlation is observed between the surface roughness and lattice strain.     

Nanoscale characterization of carbazole-indole copolymers modified carbon fiber surfaces

Polycarbazole, carbazole and indole containing copolymers were electrochemically coated onto carbon fiber. The resulting polymers and copolymers were characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Characterization of the thin polymer films were performed on the polymer-coated surface of the carbon fiber. Therefore, the results obtained could elucidate the relationship between the initial feed monomer ratio, the resulting polymer/copolymer film morphology and the surface structure formed. The thickness increase (in diameter) was 0.3 and 0.9 microm, for two different composition of carbazole/indole on the carbon fiber. The carbon fibers coated with copolymer thin films were from 6.5 to 8.2 microm in diameter (from AFM measurement).     

Poly(acrylonitrile-co-itaconic acid)–poly(3,4-ethylenedioxythiophene) and poly(3-methoxythiophene) nanoparticles and nanofibres

This work aimed to produce poly(acrylonitrile-co-itaconic acid) (P(AN-co-IA)) nanocomposites with poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3-methoxythiophene) (PMOT). An anionic surfactant sodium dodecyl benzene sulphonate was used in emulsion polymerization for nanocomposite production. Incorporations of PEDOT and PMOT on the nanoparticles were characterized by scanning electron microscopy (SEM), atomic force microscopy, Fourier transform infrared-attenuated total reflectance spectroscopy and ultra-violet spectroscopy. These nanoparticles were blended with PAN and the blends were electrospun to produce P(AN-co-IA)–polythiophene-derivative-based nanofibres, and the obtained nanofibres were characterized by SEM and energy dispersive spectroscopy. In addition, electrochemical impedance studies conducted on nanofibres showed that PEDOT and PMOT in matrix polymer P(AN-co-IA) exhibited capacitive behaviour comparable to that of ITO–PET. Their capacitive behaviour changed with the amount of electroactive polymer.