Doped-SiCNT as a promising sensor for detection of CS2 molecule

In order to explore the novel sensors for detection of carbon disulfide (CS₂) molecule, the electronic sensitivity of Pd or Ni–SiCNT to CS₂ molecule is investigated using density functional theory and dispersion-corrected density functional theory methods. The adsorption energy, charge transfer, density of states and molecular frontier orbital of all systems are also analyzed. The adsorption energy values reveal that Pd_Si or Ni_Si–SiCNT weakly adsorbed the CS₂ molecule and their electronic properties do not change by adsorbing a gas molecule. While replacing C atom with Ni and Pd atoms can enhance the adsorption energy. Moreover, it is found that the electronic properties of Pd_C or Ni_C–SiCNT are changed upon exposure to the CS₂ molecule. And Ni_C–SiCNT has more sensitivity to CS₂ when compared to other considered nanotubes. Therefore, Ni_C–SiCNT is more suitable for detection and CS₂ adsorption than other investigated nanotubes. NBO analysis reveals that electrons transfer from the CS₂ molecule to the nanotube. ¹³C and ²⁹Si chemical shielding tensors are computed using the gauge-independent atomic orbital method. Nuclear magnetic resonance calculations reveal that the isotropy parameters at the sites of Si nuclei which are directly bonded to the impurity atoms undergo significant changes.     

Low Pressure Hexamethyldisiloxane (HMDSO)/Nitrogen Plasma Treatment on the Wettability and Surface Free Energy of Biaxial-Oriented Polypropylene (BOPP) Films

In this paper the influence of DC glow discharge HMDSO-N₂ plasma on wettability and surface properties of Biaxial-oriented polypropylene (BOPP) polymeric surfaces, has been investigated. The effects of plasma exposure time and HMDSO percent on the surface energy and wettability of the BOPP films were characterized using Fourier transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM) and contact angle measurement. A clear change in the surface energy of BOPP films due to plasma treatment was observed. In this work we report changing surface properties of BOPP films instead of plasma treatment time and HMDSO ratios.     

A framework for virtual organization creation in a breeding environment

Effectiveness in the process of creating virtual organizations (VO) is an important pre-condition for having a truly dynamic VOs, in response to collaboration opportunities in fast changing market contexts. A realistic approach to materialize agility in VO creation is defined under the assumption of a VO Breeding Environment (VBE), that guarantees the preparedness of its members to quickly get engaged in collaboration processes. After a survey of past approaches and a characterization of the VBE concept, a discussion of the process and suggested functionalities towards a VO creation framework are presented in this context. Finally a list of supporting tools is described and future research challenges are pointed out.     

Novel fabrication of PdCu nanostructures decorated on graphene as excellent electrocatalyst toward ethanol oxidation

In this study, the electrochemical reduction reaction of copper(II) formate on the graphene/glassy carbon electrode (G/GCE) surface in the HCl (5 wt.%) was employed for fabrication of the PdCu nanostructures by galvanic displacement reaction. This method has a number of advantages including being environmentally-friendly, simplicity, inexpensiveness and fast. The PdCu nanostructures decorated on the G/GCE were fabricated in two steps: (1) electrochemical reduction reaction of copper(II) formate to Cu on the G/GCE and (2) the galvanic replacement reaction between Cu and Pd²⁺ ions. The physical and electrochemical properties of as-prepared PdCu/G were investigated via Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Cyclic Voltammetry, Chronoamperometry, and Electrochemical Impedance Spectroscopy. The PdCu/G compositional effect on ethanol oxidation in alkaline media is investigated. The results were shown that the catalytic activity and durability of PdCu/G catalyst are superior to those of Pd/C electrocatalyst for ethanol oxidation. The PdCu/G increased the current density 6.2 times more than Pd/C with a 50 mv negative shift in onset potential for electrooxidation of ethanol. Besides, the novel PdCu/G catalyst exhibits large electrochemically active surface area, lower apparent activation energy, higher levels of stability, poisoning tolerance, and lower charge transfer resistance compared to the Pd/C for the oxidation of ethanol.     

A simple and fast method for the preparation of super active Pd/CNTs catalyst toward ethanol electrooxidation

For the first time, galvanic reduction by zinc sheet is used as a new strategy to prepare modified electrodes. In this work, glassy carbon electrode (GCE) was modified by decoration of Pd nanostructures on carbon nanotubes (Pd/CNTs). In this method, deposited PdCl₂ on CNTs was directly reduced to metallic Pd nanostructure using a zinc sheet in HCl (2% w/w) solution. This approach offers a number of advantages including being very fast, simple and green; and modified electrodes show high activity. The prepared catalyst is characterized by Field Emission Scanning Electron Microscopy, X-Ray Diffraction and energy-dispersive X-ray and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). In addition, electrochemical measurements show that the performance as well as the stability of the as-prepared catalyst for ethanol oxidation is outstanding. The Pd/CNTs catalyst shows higher mass current density, which is 7.9 times as high as that of commercial Pd/C.     

Particle Swarm Optimization for Automatic Calibration of Large Scale Water Quality Model (CE-QUAL-W2): Application to Karkheh Reservoir,Iran

An automatic calibration of water quality model is developed in this research. Automatic calibration as the process to determine the parameters appearing in the equations of a 2-dimensional, hydrodynamic, and water quality models (CE-QUAL-W2) is carried out with Particle Swarm technique as an optimization tool. In the calibration of the CE-QUAl-W2 model, evaporation as a significant parameter influences the thermal profile and water surface elevation in reservoir, simultaneously. Therefore to consider the simultaneous effects of the water temperature variations on water surface elevation in the reservoir, a multi objective technique is used to minimize the weighted sum of total deviations of temperature from field data at check points on monitoring days and those of water surface elevation on daily monitoring period. The proposed approach overcomes the high computational efforts required if a conventional calibration search technique was used, while retaining the quality of the final calibration results. The automatic calibration approach is applied in temperature and water budget calibration of Karkheh reservoir in Iran. Applying the proposed automatic calibration approach, shows the produced results by the CE-QUAL-W2 model with the calibrated coefficients agree closely with a set of field data.     

Sub-recoil-limit laser cooling via interacting dark-state resonances

We propose a laser cooling mechanism based on velocity-selective double-dark resonance that leads to a temperature significantly lower than the one-photon recoil limit. This mechanism benefits from sharp and high-contrast spectra which are induced by the two electromagnetically induced transparency windows due to the interacting dark-state resonances. It is theoretically demonstrated that four-level atoms illuminated by two counter-propagating probe beams and two additional beams directed perpendicularly to the other two exhibit new cooling effects; for red detuned probe lasers, atoms can be subject to a strong viscous force with an extremely small diffusion, characteristic of heating caused by the stochastic nature of spontaneous emission processes. By quantum mechanical simulations, we then find that the lowest temperature in EIT windows approaches 1?nK for the case of mercury. However, the different broadening mechanisms can destroy the cooling, so that the lowest temperature can increase to the recoil temperature.     

Natural frequency and critical speed determination of an axially moving viscoelastic beam

In this paper, the natural frequency and critical speed of an axially moving viscoelastic beam with clamped and simple supports are calculated analytically based on the Euler–Bernoulli and Timoshenko theories. The beam is incompressible in bulk and viscoelastic in shear, which obeys the linear standard solid model with material time derivative. The axial speed is characterized by a simple harmonic variation about a constant mean speed. By defining some dimensionless parameters, the governing equations are derived from the Newton’s second law. They contain two coupled partial differential equations with time depended coefficients. The straightforward method in perturbation theory is used to solve these equations. By considering the homogeneous equation, the natural frequencies are calculated. The critical speed is determined by a constant speed assumption. By a parametric study, the effects of mechanical and geometrical parameters on the natural frequency and critical speed are investigated.     

The PRODNET cooperative information management for industrial virtual enterprises

When designing an IT platform aimed at supporting industrial virtual enterprises (VEs), certain issues related to information management requirements become especially challenging, such as the physical distribution of data, the enterprise autonomy and privacy enforcement, access rights to shared information, and data visibility levels, among others. In the ESPRIT project PRODNET II, a federated database architecture was designed and implemented as the base support framework to effectively manage these issues associated with the sharing and exchange of information in the VE environment. In this paper, first the general information management requirements identified for the VE network in the PRODNET II project are described, and then the challenging design issues behind the development of the components of the federated information management system are presented.