Papers by Keyword: Cr

Abstract: Present work illustrates synthesis of Cr doped WO₃ nanostructures (NS) (2 wt. %, 4 wt. % and 6 wt. %) by co precipitation method using surfactants and reported enhanced impedance, capacitance-voltage and current-voltage (I-V) characteristics. NS were characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Visible (UV-Vis) spectroscopy, pelletized samples performed I-V, C-V and impedance measurements. Impedance results reveal that the pelletized samples of highest doped Cr showed remarkable increase in admittance with respect to the biased voltage. I-V characteristics of highest doped Cr exhibited enhanced surface conductivity as compared with applied current. The output power considerably increases for the 6 wt. % of Cr doped WO₃ and doping percentage of Cr increases surface conductivity, power output, admittance considerably enhances in the material matrix. This work demonstrated that Cr doped WO₃ has more sensitivity towards I-V, C-V and impedance value considerably varies with the applied bias voltage. The limitation is not certain in case of doped nanomaterials of Cr-WO₃, since these materials possesses nonlinear properties and can find applications in the diversified filed of nano electronics. The authors reported work can be a key guide for the upcoming researchers in the area of biomedical devices, nanoelectronics, sensors, wherein Cr-WO₃ NS finds applications because of its enhanced I-V, C-V, Impedance characteristics. The work has been carried out to understand the electrical and electronic properties of doped nanomaterials in the original work place and analysis has been carried out at various institutions where the provisions for the experimentation is being made.

Abstract: Multilayer coating onto orthopedic implants has been studied extensively due to their excellence mechanical and biological properties. A multilayer coating was coated onto metal implants to prevent the leaching of metallic ions into human body. This paper aims to study the hardness of multilayer coatings of Chromium (Cr), Chromium Nitride (CrN), Chromium Carbonitride (CrCN) and Zirconium Nitride (ZrN) by Physical Vapour Deposition (PVD). The deposited multilayer coating was characterised by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX). Cr, CrN, CrCN and ZrN have been successfully deposited onto stainless steel substrates by PVD. XRD analysis detected major peak in preferred orientation of (200) and other peaks with (111), (220), (311) for CrN cubic phase. For CrCN, XRD analysis detected only low intensity peaks of Cr₇C₃ and ZrN peaks with preferred orientation of (111), (200) with other peak (220), (311) and (222). Microvickers Hardness results showed an increment in hardness value from substrates with 160HV to 174HV for Cr, 236HV for CrN, 362HV for CrCN, 364HV for ZrN and 370HV for multilayer coatings.

Abstract: It is all known that the BN sheet is a nonmagnetic wide-band-gap semiconductor. Using Density Function Theory (DFT), the lattice parameters of Cr doped BN sheets were optimized, which were still kept on 2D planar geometry, and the band gap was studied. The simulation results show that the band gap is very easy to be tuned by Cr doped BN sheet, which is more stable structure. So Cr doped BN sheet is a promising material in modulating the band gap and through tuning the band gap it can be a highly efficient photocatalytic material et al. Because Cr is poisonous and harmful substance, it does harm to people’s health and environmental pollution, particularly, heavy metal contamination in soil. So Cr doped BN sheet is a promising material in modulating the band gap, through tuning the band gap it can be a highly efficient photocatalytic material and benefit humanity and protect the environment et al.

Abstract: A new configuration of chromizing process was developed by separating Cr powder from NH₄Cl. FC220 gray cast iron specimens were chromized in this new experimental setup at 450, 550, 650,750, 850 and 950°C during 13 hours in order to study the possibility of chromizing at “low” temperature. The chromized specimens were examined using Scanning Electron Microscopy (SEM), macro-hardness, micro-hardness, compression test and salt spray test. The results shows that the specimen chromized at 650°C gives the best compromise between the corrosion resistance and the hardness of the FC220 with 1.73 ڌm of thickness of the chromized layer. However, after 13 hours of the process, the hardness of the FC220 specimens decreased considerably from 93 HRB to 64.2 HRB (31%).

Abstract: The formation of anti-wear coatings on the inner surface of steel cylinders and pipes presents a difficult process-related problem for PA PVD methods. This problem is associated with a strictly limited geometry of the reaction space and dimensions of plasma sputtering-sources. Among the main factors behind physical and chemical phenomena occurring the reaction space, formed within a low-temperature plasma and at its boundaries with a solid object, there are type, concentration, unobstructed path for reacting substances, as well as values and geometry of electrical/magnetic/thermal fields [1-5]. In the research on the plasma-based technology in confined space, the lowest possible distance between the surface being modified and the source of ions of metallic and gaseous elements is taken into account.

Abstract: Based on investigation dada on Cr in 1982 in Jiaozhou Bay, this paper analyzed the seasonal and spatial distribution of Cr, and revealed the transfer process of Cr. Results showed that horizontal diffusion and vertical sedimentation were major transfer processes of Cr, which were mainly determined by water exchange and gravity settling. These findings were essential to pollution control and environmental remediation in Jiaozhou Bay. From the point of view of pollution control, reducing the discharge of Cr from the sources was the major countermeasure.

Abstract: Medical imaging is important in trendy medical aid that gives diagnostic info for clinical management of patients and designing of treatment. Every year, terabytes of medical image data’s square measure used through advanced imaging modalities like Positron Emission Tomography (PET) Magnetic Resonance Imaging (MRI), Computed Tomography (CT), and lots of additional new methodology of medical imaging. Advances in technology have created the chance for radiology systems to use complicated compression algorithms to scale back the file size of every image in an attempt to partly offset the rise in knowledge volume created by new or additional complicated modalities whereas protective the numerous diagnostic info. This paper outlines the various compression strategies like Discrete Cosine Transform (DCT), Fractal Compression and Set Partitioning In hierarchical Trees (SPIHT) applied to numerous medical pictures. Experimental results show that the projected SPIHT approach achieves the next Compression Ratio (CR), Bits Per Pixel (BPP) and Peak Signal to Noise Ratio (PSNR) with less Mean square Error (MSE) in comparison with DCT methodology.

Abstract: The concentration and distribution of Cr, Pb and Zn in 22 Jurassic coals from northern Shaanxi,and Ningxi, China were studied. The samples were collected from eight coal mines of five different region, including Yuyang Region, Hengshan, Shenmu, Huangling and Lingwu. Comparing with Chinese coals, American coals and coal Clarke value: Pb showed different degree enrichment in the study region except Ningxia ; Cr was enriched in Shenmu coals, Huangling coals and Hengshan coals; whereas the content of Zn in the study region coals was lower than in American coals. Horizontal variation of the three elements in the study region indicated that different elements showed different variation trend. Based on statistical analyses, Pb showed a moderate relationship with ash yield, whereas Cr had a high correlation coefficients with total sulfur.

Abstract: Dissolved organic matter is an important and active component in both terrestrial and aquatic ecosystem. It has become a hotspot in environment science, with active functional groups such as carboxyl, hydroxyl, amino that can influence adsorption and migration of heavy metal contaminants in soil system. Through soil column leaching experiment the article demonstrates that Cr (VI) is dominated by physical adsorption in soils. By using DOM eluent and distilled water to leach at different temperatures in soil, this article shows that release ability of Cr increases with temperature rising, while its deposition capacity increases with temperature decreasing in Water Level Fluctuating Zone. Combined with Gibbs theory, Cr (VI) may take complexation reaction with DOM in soil medium. Thus, new substances appear under the proof of XRD graph.

Abstract: Abstract. Sintered powder metallurgy Fe based composites with advanced mechanical properties have been proposed as substitutes for more expensive cemented carbide and wrought alloys in many applications, especially as inexpensive wear resistance parts. The aim of this work was to fabricate and characterize a composite made of Fe-Cr as the matrix and Al2O3 particles as reinforcement. The composite was made by powder metallurgy method. The effect of different amount of binder, mixing duration, compaction pressure and sintering temperature has been investigated. Densification, micro hardness, wear resistance and compressive strength were used to characterize the composite. Powder metallurgy parameters that satisfy the composites quality have been optimized and result showed that higher sintering temperatures promote good sintering in the composites which produced better densification, higher reading of micro hardness, better wear resistance and compressive strength.