FE analysis on tube hydroforming of small diametr ZM21 magnesium alloy tube

Tube hydroforming (THF) is one of the plasticity processing methods. Tubular parts, for instance automotive components are expanded by forces such as internal pressure and axial compression in order to deform an objective shape. THF has less restriction on shape and size of workpieces owing to adopting the liquid tool. The demand of a small diameter magnesium alloy tubular parts have been increased for applying small medical and electronic devices. In this study, it was investigated that influence of process conditions such as processing temperature, internal pressure and axial feeding amount on formability of small diameter ZM21 magnesium alloy tube with outer diameter of 2.0mm and thickness of 0.20mm. Furthermore, the processing conditions for improving the formability of material in THF were examined. For prior evaluation of deformation characteristics in the warm THF of small diameter ZM21 magnesium alloy tube, a finite element (FE) simulation was conducted. The FE method (FEM) code was used LS-DYNA 3D for analysis of the FE model of the tube and the dies. The material characteristics were obtained by tensile test and fracture test. From FE analysis results, it was elucidated that effect of the processing temperature, the variable internal pressure and the axial feeding amount on deformation behavior. The formability of ZM21 magnesium alloy tube was improved by processing at 250 C. The difference of deformation characteristic between FE results and experimental results was compared. As the results, the processing condition which could improve the formability of ZM21 tube was clarified using this FE model. The effect of adding the straightening stage in the loading path after the preform on formability was investigated. The thinning of the wall thickness of the tube was inhibited by calibration after the axial feeding

Decoherence of flux qubits due to 1/f flux noise

We have investigated decoherence in Josephson-junction flux qubits. Based on the measurements of decoherence at various bias conditions, we discriminate contributions of different noise sources. In particular, we present a Gaussian decay function of the echo signal as evidence of dephasing due to $1/f$ flux noise whose spectral density is evaluated to be about $(10^{-6} \Phi_0)^2$/Hz at 1 Hz. We also demonstrate that at an optimal bias condition where the noise sources are well decoupled the coherence observed in the echo measurement is mainly limited by energy relaxation of the qubit.Comment: 4 pages, error in Fig.4 corrected, to appear in PR

Fundamental Cycle of a Periodic Box-Ball System

We investigate a soliton cellular automaton (Box-Ball system) with periodic boundary conditions. Since the cellular automaton is a deterministic dynamical system that takes only a finite number of states, it will exhibit periodic motion. We determine its fundamental cycle for a given initial state.Comment: 28 pages, 6 figure

Role of electrolyte on anodic mineralization of atenolol at boron doped diamond and Pt electrodes

Anodic oxidation of atenolol, known as -blocker, has been investigated using boron-doped diamond(BDD) and Pt electrodes. The mineralization trend of atenolol in the presence of NaCl, Na2SO4 and NaNO3 was followed using total organic carbon analyzer. The disappearance of chloride ions and generation of active chlorine (Cl2, HOCl, OCl−) were analysed by argentometric and iodometric methods, respectively. The BDD anode was found to be effective in the presence of Na2SO4 whereas Pt yields better removal in the presence of NaCl. The initial concentration of NaCl and applied current density on the mineralization of atenolol were found to be significant for both BDD and Pt anodes. These results are explained in terms of electrogenerated oxidants such as •OH, SO4•−, S2O8 2−, Cl2, HOCl and OCl−. The evolution of chlorine at BDD and Pt with respect to NaCl concentration was studied by means of cyclic voltammetric technique. Though the rate of mineralization was observed to be initially higher in the presence of Pt anode, the overall rate of mineralization is more or less similar beyond 15 h of electrooxidation. The slow degradation at the later stages of electrooxidation was attributed to the presence of residual chlorinated organic compounds which are very refractive. The complete mineralization was achieved in the presenceof Na2SO4 using BDD as anode

Anodic oxidation of ketofrofen-an anti-inflammatory drug using boron doped diamond electrode

The mineralization of ketoprofen (KP) by anodic oxidation was studied by employing boron doped diamond (BDD) and Pt electrodes. The redox behavior of KP molecule, fouling of electrodes, generation of oxygen and active chlorine species were studied by cyclic voltammetry. The effect of electrolyte, pH of aqueous medium and applied current density on the mineralization behavior of KP was also investigated. The degradation and mineralization were monitored by UV–vis spectrophotometer and total organic carbon analyzer, respectively. The results were explained in terms of in situ generation of hydroxyl radical (•OH), peroxodisulfate (S2O8 2−), and active chlorine species (Cl2, HOCl, OCl−). The physisorbed •OH on BDD was observed to trigger the combustion of KP in to CO2 and H2O. The poor mineralization at both BDDand Pt anodes in the presence of NaCl as supporting electrolyte was ascribed to the formation of chlorinated organic compounds which are refractory. Complete mineralization of KP molecule was achieved using Na2SO4 as supporting electrolyte

Treatment of pharmaceutically active compounds by electrooxidation using boron doped diamond and platinum anodes

Clean and hygiene water is a critical environmental issue that touches the life of every human being. In recent years, presence of some pharmaceutical compounds and their metabolites in surface and ground water has become a potential health risk to human beings. Non-steroidal anti-inflammatory drugs (NSAID) are prescribed for muscle pain and inflammatory rheumatic disorders. Ketoprofen one of the NSAIOs, is categorized as a pharmaceutically active compound which resists both the abiotic and biotic degradation. Similarly, P-blockers are a class of drugs used for various indications particularly to control high blood pressure, anti-angina and cardiovascular diseases. One among the P-blockers, atenolol is most toxic to humans and aquatic organisms. The presence of both ketoprofen and atenolol in ground water has been reported at concentrations up to 10 figlL. A bench scale study was carried out to treat synthetically prepared pharmaceutical compounds (ketoprofen and atenolol) contaminated water in lower concentrations (fig/I) using boron doped diamond (BOD) and platinum anodes. The results were explained in terms of in situ generated of hydroxyl radical COH), peroxodisulfate (S20t), and active chlorine species (CI2, ocr and HOCI). The physisorbed 'OH on BOD was observed to trigger the combustion of pollutant molecules in to CO2 and H20. The BOD anode was found to be effective in the presence ofNa2S04 whereas Pt yields better removal in the presence of NaCI. The influence of electrolyte pH on the mineralization of ketoprofen molecules was found to be insignificant

Rab8a and Rab8b are essential for several apical transport pathways but insufficient for ciliogenesis

The small GTP-binding protein Rab8 is known to play an essential role in intracellular transport and cilia formation. We have previously demonstrated that Rab8a is required for localising apical markers in various organisms. Rab8a has a closely related isoform, Rab8b. To determine whether Rab8b can compensate for Rab8a, we generated Rab8b-knockout mice. Although the Rab8b-knockout mice did not display an overt phenotype, Rab8a and Rab8b double-knockout mice exhibited mislocalisation of apical markers and died earlier than Rab8a-knockout mice. The apical markers accumulated in three intracellular patterns in the double-knockout mice. However, the localisation of basolateral and/or dendritic markers of the double-knockout mice seemed normal. The morphology and the length of various primary and/or motile cilia, and the frequency of ciliated cells appeared to be identical in control and double-knockout mice. However, an additional knockdown of Rab10 in double-knockout cells greatly reduced the percentage of ciliated cells. Our results highlight the compensatory effect of Rab8a and Rab8b in apical transport, and the complexity of the apical transport process. In addition, neither Rab8a nor Rab8b are required for basolateral and/or dendritic transport. However, simultaneous loss of Rab8a and Rab8b has little effect on ciliogenesis, whereas additional loss of Rab10 greatly affects ciliogenesis