Papers by Keyword: Co

Abstract: This study aims to determine the effect of installing modified copper C-SiO₂-ZSM5 in the exhaust, installing modified copper in the exhaust to reduce CO and HC. The two methods used to reduce CO and HC exhaust emissions are as follows: the first method is by mixing fossil fuels with ethanol. The fuel used is a mixture of gasoline + ethanol with variations of gasoline, E10, and E20. The second method is to provide a CO and HC reformer catalyst made of modified copper with the addition of SiO₂ and MZM5 as much as 10% and 20%, respectively. The test uses a four-stroke two-wheel motor in a neutral gear position. Exhaust emission data retrieval is at 1500, 3000, 5000, 7000, 9000 rpm. With gasoline fuel mixed with ethanol with E 10 and E 20. There is a decrease in CO at each engine speed in each fuel variation, because the more ethanol content, the greater the supply of O₂ in combustion because ethanol has oxygen bonds that can increase combustion. The emission of CO and HC gas on gasoline-fueled motors are greater than those of E 10 and E 20 motors. The use of a copper converter catalyst SiO₂-C-ZSM5 is very significant and can reduce CO levels for gasoline fuel from the highest value of 4,7% to 2.82%, gasohol fuel E 10 with the highest value of CO 3.02% decreased to 1.2% and gasohol fuel E 20 the highest value of CO 2.78% decreased to 0.17%. Changes were seen visually on the surface of the copper used for the CO and HC reduction test, the surface copper became darker in color, especially when testing using gasoline. When using a mixture of ethanol and gasoline, copper is purplish brown color.

Abstract: In this paper, the effects of different Co contents on the microstructure and properties of Al-30% Si alloy were studied by means of metallographic microscope, microhardness tester, XRD, conductivity tester and DSC thermal analyzer. The results show that cobalt can effectively improve the microstructure of the alloy, the long needle eutectic silicon becomes short rod, and the coarse irregular block primary silicon particles become smaller. When 0.3% cobalt is added into the alloy, the refining effect of eutectic silicon is the most obvious. When the amount of Co is 0.6%, the refinement effect of primary silicon is the best. The addition of Co can improve the hardness of the alloy. When 0.6 ~ 0.9% cobalt is added, the hardness is the highest. With the increase of Co content, the conductivity and transformation latent heat of the alloy show the same change law. When 0.6% cobalt is added, its value is the maximum. It can be seen that when the Co content is 0.6%, the microstructure and comprehensive properties of the alloy are the best.

Abstract: Present study reports the Synthesis, optical study of cobalt doped antimony based nanocomposites, which have been prepared by using CoCl₃ (0.1M) and SbCl₃ (0.1M) in 1:2 ration. The as-synthesized nanocomposites (NS) were analyzed by SEM (scanning electron microscopy), XRD (X-ray diffraction spectroscopy) and UV-Visible spectroscopy The prepared Co:α-Sb₂O₄ NS are well crystalline with average particle size of 35 to 56 nm. From XRD data X-ray diffraction patterns confirms the orthorhombic phase. From scanning electron microscopy study it shows irregular shape of nanoparticles and crystallinity increases from 36 nm to 56 nm. From optical property studies the blue shift in UV-Visible spectrum of Co:α-Sb₂O₄ NS is due to overloading of Co ions which intern creates lattice defects. The direct optical band gap (Eg) for Co:α-Sb₂O₄ NS (10 %) was found to be 3.28 eV.

Abstract: The sensing characteristics of pristine, Ni-doped, and C-vacancy graphene towards CO and NO₂ gas molecules were studied using density functional theory (DFT). The adsorption energies, electronic properties, charge transfer, and stable geometries were calculated to evaluate the gas-surface interaction mechanisms. Both pristine and vacancy graphene have smaller CO and NO₂ adsorption energies and charge transfer than the Ni-doped graphene, whereas the adsorption energy on Ni-doped vacancy graphene is higher than that of Ni-doped graphene. The results indicate that both CO and NO₂ gas molecules only attach to pristine graphene through weak physical adsorption. Stronger chemisorption occurs when the gas molecules adsorb on the surface of vacancy, Ni-doped, and Ni-doped vacancy graphene. Additionally, the results demonstrated that Ni-doped vacancy graphene has higher sensitivity and selectivity towards the NO₂.

Abstract: During silicide formation, unreacted NiPt metals is traditionally removed either by aqua regia (ESH concern) or SPM. This latter can easily degrade the device yield in HKMG (High K Metal Gate) nodes if the metal gates (usually TiN based) aren’t perfectly encapsulated. First some new characterizations are presented to better understand the NiPt metal alloy removal, then a new solution is given to be able to remove this alloy without degrading HKMG materials.

Abstract: SnO₂-based sensor has many advantages such as low cost, small size, high reliability, and long operating life, but selectivity has been a major obstacle on the application for discriminating gas species in mixture of multi-reduction gases. To resolve the problem in this work, the pure SnO₂ and NiO-, CuO- and Pt-modifying SnO₂ as sensing materials were prepared by sol-gel method, the sensor cells were fabricated and characteristics of sensitivity and selectivity of the sensor cells to CO and H₂ at 400°C were investigated. The results showed that the response of CO was improved obviously by doping 20mol%NiO or 5mol%CuO into the SnO₂, while the response of H₂ was changed no more, and the responses of CO and H₂ both were enhanced dramatically by bearing 1mol%Pt into the SnO₂. On the basis of empirical equation (R=1+kCⁿ), two sensor cells with different selectivity were introduced to assemble a novel SnO₂-based sensor, and proposed a potential method to detect the concentrations of CO and H₂ in multi-component gases, in which the parameters of k and n for sensor cells were obtained and feasibility of the method was demonstrated.

Abstract: The multilayer films [Al₂O₃/t_Co Co/t_Pt Pt]_N, produced by sequential deposition of Co and Pt on alumina consist in layers of CoPt alloyed nanoparticles. They show perpendicular magnetic anisotropy (PMA) below a freezing temperature T_f, an asperomagnetic-like phase below that temperature, and hard ferromagnetic ordering below a transition temperature T₁ < T_f. A single layer granular film (N = 1) with deposition thicknesses t_Co=0.7 nm, t_Pt=1.5 nm and particle diameter of 3 nm is presently studied. SQUID magnetometry shows that a single layer presents the three phases as well. Para-, aspero-and ferromagnetic phases are observed upon lowering the temperature, with transition temperatures T_f ≈ 375 K and T₁ ≈ 200 K, respectively. In addition, the PMA persists, proving that there is no interlayer coupling in the multilayer system. SQUID results also reveal a core-shell structure in the CoPt nanoparticles.

Abstract: The electronic structure, band structure and optical properties of Co,C co-doped AlN are investigated by first-principles calculations. The calculated results show that some impurity bands emerge near the Fermi level, and the degree of hybridization becomes stronger for Co 3d states and Al 3s states. Which indicates that the electron transition become more active from valence band to conduction band and the electrical conductivity is enhanced. Compared with intrinsic AlN, the optical properties of co-doped AlN improves a lot. There emerge some new peaks in the low energy region and the absorption coefficient, reflectivity and refractive index has large improvement in visible and infrared range.

Abstract: Pure SnO₂ and Pt doped SnO₂ (0≤Pt≤10wt.%) ceramics have been successfully fabricated in the form of pellet by sintering at 1000 °C for 3 h. The resistance of the samples in air and in reducing gases (200 ppm H₂ and 200 ppm CO) was determined by measuring current – voltage (I-V) characteristics via two-probe method between 150 to 450 °C. All samples show a decrease in resistance with an increase in temperature both in air and in gases. However, the values of resistance in gases are lower compared when the same samples were in air, due to gas molecules reactions with surface oxygen species which affect potential barrier to decrease and causes resistance to reduce. The resistance of the doped samples also increased by 279 - 1226% with an increase in Pt doping in SnO₂, due to Pt surface states density.

Abstract: Vehicular pollution is one of the main reasons for air pollution in many cities. According to Industrial Environment Carbon, every gallon of gasoline produces 14% total volume of carbon dioxide, this will ultimately lead to air pollution and global warming [10]. To minimize the emission level, physical adsorption [4] can be used for the removal of organic molecule from exhaust gas stream by impulse collision. So our proposed system consists of a filter matrix bed, made of activated carbon, calcium hydroxide, lithium hydroxide [8,9]. Activated carbon is the most widely used adsorbent. It can adsorb a wide range of pollutants with varying dimensions by its broad pore distribution, micro and mesophores. Calcium group can naturally adsorb carbon component and get transformed into lime. Lithium hydroxide is widely used as carbon capturing material in space craft for adsorbing carbon dioxide exhaled by astronaut as a breathing scrubber. So collectively these three carbon sequestrating material can efficiently remove the pollutant by chemisorptions [2].