Esterification of valeric acid over PTA supported mesoporous Al-SBA-15 as efficient solid acid catalysts

Journal of Porous Materials - Valeric acid can be produced by selective hydrogenation of biomass-derived levulinic acid. The present work aims to synthesize ethyl valerate (EV), a fuel, fuel...     

Encrypted Network Traffic Classification and Resource Allocation with Deep Learning in Software Defined Network

Wireless Personal Communications - The climate has changed absolutely in every area in just a few years as digitized, making high-speed internet service a significant need in the future. Future...     

Mesoporous Ru/Sn-SBA-15 catalysts: synthesis,characterization and catalytic activity towards hydrogenation of levulinic acid

Journal of Porous Materials - Among the various biomass-derived platform chemicals, levulinic acid (LA) has been identified as one of the top-10 important molecules by Department of Energy, United...     

Virtual synchronous machine-controlled grid-connected power electronic converter as a ROCOF control device for power system applications

Electrical Engineering - Rate of change of frequency (ROCOF) is an indicator of frequency stability of a power system network. Maintaining the ROCOF value within the acceptable limit is a major...     

Cost optimization of process tolerance allocation-a tree based approach

Tolerance transfer techniques are used extensively for allocation of tolerances for each machining operation in the process sequence, and hence are used to coordinate the process planning and the design activities in the evolution of a new product. This paper deals with an extended approach to allocate process tolerances based on a tree topology called technologically and topologically related surfaces (TTRS) and its subsequent extension to cost optimization. The benefit of this approach is that equations are generated explicitly with regard to tolerance transfer. These have been exploited by implementing the cost function in the generated explicit equations and subsequent optimization. The TTRS approach has been extended which scores over the limitations of some of the already existing techniques in that, it is optimal with respect to two factors namely, cost of producing the required tolerances, as also the process capability of the machines involved in producing the part. This technique has been proved practically feasible as it has been implemented in an industry. To enable a better view of the advantages of the approach, a comparative study with the existing techniques has been carried out in addition to a simulation using the Monte Carlo method.     

Photoreduction of Cr(VI) in water using Bi2O3–ZrO2 nanocomposite under visible light irradiation

Chromium(VI) is a common heavy metal pollutant and extensively used in variety of industrial processes. In the present study, bismuth oxide–zirconium oxide nanocomposite (Bi₂O₃–ZrO₂) was synthesized to improve photoreduction of Cr(VI) under visible light irradiation. The synthesized photocatalyst was characterized by UV-visible-diffuse reflectance spectroscopy (UV-vis-DRS), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Brunauer–Emmett–Teller (B.E.T) surface area analysis and photoluminescence spectroscopy (PL). Bi₂O₃–ZrO₂ was found to be more photoactive than Bi₂O₃, ZrO₂, TiO₂ and ZnO for the reduction of Cr (VI). The influences of various reaction parameters like the effect of catalyst concentration, initial Cr(VI) concentration and addition of inorganic salts on the photocatalytic activity have been investigated in detail. Meanwhile, the stability of Bi₂O₃–ZrO₂ was investigated by repeatedly performing Cr(VI) photoreducing experiments.     

Synthesis of Fe/ZnO composite nanocatalyst and its sonophotocatalytic activity on acid yellow 23 dye and real textile effluent

Nanocatalysts such as ZnO, Fe and Fe/ZnO composite were synthesized for better treatment of dye than the conventional treatment methods. The catalysts were characterized using SEM, EDAX, BET surface area, XRD and DRS. The degradation of acid yellow 23 dye in aqueous solution has been investigated using sonolysis, photolysis and sonophotocatalysis. The effect of different conventional operating parameters such as initial solution pH, gas purging (Argon, Oxygen, Air and Nitrogen) and H₂O₂ addition, under sonolysis (13 and 25 mm probe tip diameter) and photolysis (UV light), showed a maximum of 41 % colour removal for 0.0187 mmol/L dye solution under photolysis with 88.2 mmol/L H₂O₂ addition. Among the catalysts used, 98 % dye colour removal was obtained with 0.2 g/L Fe/ZnO composite under 60 min of sonophotolysis that had been benefitted by the synergistic effects. The HPLC spectrum of the untreated dye and treated dye supports the claim of eradication of the parent dye compound. Sonophotocatalytic treatment of real textile effluent in the presence of 6 g/L Fe/ZnO composite and 264.6 mmol/L H₂O₂ reduced the COD level from 792 to 174.4 mg/L in 240 min to meet the allowable effluent discharge standard into running water streams. The studied treatment methods were found to be effective for the degradation of acid yellow 23 dye and subsequently in real textile effluent too.     

Microfluidic characterization and continuous separation of cells and particles using conducting poly(dimethyl siloxane) electrode induced alternating current-dielectrophoresis

This paper presents a poly(dimethyl siloxane) (PDMS) polymer microfluidic device using alternating current (ac) dielectrophoresis (DEP) for separating live cells from interfering particles of similar sizes by their polarizabilities under continuous flow and for characterizing DEP behaviors of cells in stagnant flow. The ac-DEP force is generated by three-dimensional (3D) conducting PDMS composite electrodes fabricated on a sidewall of the device main channel. Such 3D PDMS composite electrodes are made by dispersing microsized silver (Ag) fillers into PDMS gel. The sidewall AgPDMS electrodes can generate a 3D electric field that uniformly distributes throughout the channel height and varies along the channel lateral direction, thereby producing stronger lateral DEP effects over the entire channel. This allows not only easy observation of cell/particle lateral motion but also using the lateral DEP force for manipulation of cells/particles. The former feature is used to characterize the frequency-dependent DEP behaviors of Saccharomyces cerevisiae (yeast) and Escherichia coli (bacteria). The latter is utilized for continuous separation of live yeast and bacterial cells from similar-size latex particles as well as live yeast cells from dead yeast cells. The separation efficiency of 97% is achieved in all cases. The demonstration of these functions shows promising applications of the microfluidic device.     

Effect of annealing on the electrical, optical and structural properties of cadmium stannate thin films prepared by spray pyrolysis technique

Polycrystalline thin films of cadmium stannate (Cd₂SnO₄) were deposited by spray pyrolysis method on the Corning substrates at substrate temperature of 525 °C. Further, the films were annealed at 600 °C in vacuum for 30 min. These films were characterized for their structural, electrical and optical properties. The experimental results showed that the post-deposition annealing in vacuum has a significant influence on the properties of the films. The average grain size of the film was increased from 27.3 to 35.0 nm on heat treatment. The average optical transmittance in the visible region (500-850 nm) is decreased from 81.4% to 73.4% after annealing in vacuum. The minimum resistivity achieved in the present study for the vacuum annealed films is the lowest among the reported values for the Cd₂SnO₄ thin films prepared by spray pyrolysis method.     

Neoplastic transformation of chronic ulcers in leprosy patients--a retrospective study of 23 consecutive cases

The costimulatory CD80 and CD86 molecules were measured by flow cytometry on cerebrospinal fluid (CSF) and blood lymphocytes from patients with possible first attacks of multiple sclerosis (MS, n = 25), clinically definite MS (n = 16), and noninflammatory neurological disease control subjects (n = 30). In patients with demyelinating diseases more CSF B cells expressed CD80 than in control subjects whereas the expression of CD86 by T cells in CSF was low in patients with demyelinating disease and highly variable in the control subjects. In patients with possible first attacks of MS the expression pattern of CD80 and CD86 differed significantly between patients with or without intrathecal synthesis of IgG. Increased expression of the CD80 molecule on CSF B cells may be of importance in the pathogenesis of MS. In contrast, CSF T cell expression of CD86 may be associated with protection from MS.