Removal of Cu(II) by biosorption onto coconut shell in fixed-bed column systems

Biosorption of Cu(II) onto coconut shell, an agricultural biomaterial, was studied in a fixed-bed column. The Cu(II) biosorption column had the best performance at 10 mg L^?1 inlet Cu(II) concentration, 10 mL min^?1 flow rate and 20 cm bed depth. The equilibrium uptake of Cu(II) amounted to 7.25 mg g^?1. The simulation of the breakthrough curve was successful with the BDST and Yoon–Nelson models, but the entire breakthrough curve was best predicted by the Clark model. The design of a fixed bed column for Cu(II) removal from wastewater by biosorption onto coconut shell can be done based on these models.     

Porous cenosphere ceramic microfiltration membrane: Preparation,characterization, permeability evaluation,and cost estimation

Ceramic membranes are now receiving greater attention and are regarded as the best alternative option for reducing energy use. There are currently a number of limitations on the use of ceramic membranes, including high raw material costs and high sintering temperatures during synthesis. Cost-effective raw materials were employed in the synthesis of ceramic membranes to get around these restrictions. Utilizing a straightforward pressing technique, circular disc-type membranes were prepared. To assess the membrane properties, the impact of sintering temperatures between 700 and 900°C was examined. By varying the sintering temperature, the average membrane pore diameter was observed. The membrane, which was sintered at 800°C, had pores that were on average 110 nm in size. Furthermore, the porosity of these synthesized membranes ranged from 22% to 35% with an average pore diameter of 74–121 nm. These manufactured membranes showed very good chemical stability when both acidic and basic solutions were used. Various characterization methods, including thermogravimetric analysis (TGA), x-ray diffraction analysis (XRD), and scanning electron microscopy (SEM), were used. Thermo-gravimetric investigation revealed that the synthesized cenosphere membrane required a minimum sintering temperature of about 700°C. The flux measured with deionized water and the applied transmembrane pressure showed an upward trend. The impact of sintering temperature on permeate flux was investigated. The results showed that as the sintering temperature increased from 700°C to 900°C, the flux reduced. It was determined that the synthesized membrane cost ₹1618.80/m².     

Stereo pairs of bright-field micrographs via Wiener-type inverse filtering

In a three-dimensional (3-D) image data set obtained through optical sectioning, each two-dimensional (2-D) segment is blurred by out-of-focus information from neighbouring focal planes superimposed on the in-focus segments from that plane. Instead of attempting to remove this redundant information over the full 3-D data set, we have developed a technique for restoring stereoscopic views. In this paper we describe the implementation of a Wiener-type inverse filtering method for generating stereo pairs of bright-field micrographs. A theoretical optical transfer function valid under certain simplifying approximations has been used in implementing this filtering technique. In developing this method the slice theorem of computed tomography is used. In this way the image reconstruction problem is reduced to one of processing 2-D arrays rather than 3-D arrays and the problem of restoring missing Fourier components within the missing-cone region is circumvented. Limited experimentation with real micrographs shows that the approach provides images that display an effective increased depth of field and 3-D attributes of the specimen, even though some of the underlying assumptions on which this method is based are difficult to verify explicitly. The method can be implemented with a relatively fast execution time on 386-SX computers.     

Automatic digitization of printed circuit layouts

A new technique for automatic input of printed circuit layout data to a computer graphics system, providing a powerful alternative to the existing manual digitization method, is described. The technique is based on optical scanning and graphics recognition. Substantial reduction in the digitized data is made possible by using the properties of printed circuit art work. The technique has been extended to encompass some areas of engineering documentation.     

Thermodynamic analysis of high‐ash coal‐fired power plant with carbon dioxide capture

A thermodynamic analysis of a 500‐MWe subcritical power plant using high‐ash Indian coal (base plant) is carried out to determine the effects of carbon dioxide (CO₂) capture on plant energy and exergy efficiencies. An imported (South African) low‐ash coal is also considered to compare the performance of the integrated plant (base plant with CO₂ capture plant). Chemical absorption technique using monoethanolamine as an absorbent is adopted in the CO₂ capture plant. The flow sheet computer program “Aspen Plus” is used for the parametric study of the CO₂ capture plant to determine the minimum energy requirement for absorbent regeneration at optimum absorber–stripper configuration. Energy and exergy analysis for the integrated plant is carried out using the power plant simulation software “Cycle‐Tempo”. The study also involves determining the effects of various steam extraction techniques from the turbine cycle (intermediate‐pressure–low‐pressure crossover pipe) for monoethanolamine regeneration. It is found that the minimum reboiler heat duty is 373 MW_th (equivalent to 3.77 MJ of heat energy per kg of CO₂ captured), resulting in a drop of plant energy efficiency by approximately 8.3% to 11.2% points. The study reveals that the maximum energy and exergy losses occur in the reboiler and the combustor, respectively, accounting for 29% and 33% of the fuel energy and exergy. Among the various options for preprocessing steam that is extracted from turbine cycle for reboiler use, “addition of new auxiliary turbine” is found to be the best option. Copyright © 2011 John Wiley & Sons, Ltd.     

Enhanced Piezoelectric,Ferroelectric, and Electrostrictive Properties of Lead-Free (1-x)BCZT-(x)BCST Electroceramics with Energy Harvesting Capability

Next-generation electronics and energy technologies can now be developed as a result of the design, discovery, and development of novel, environmental friendly lead (Pb)-free ferroelectric materials with improved characteristics and performance. However, there have only been a few reports of such complex materials’ design with multi-phase interfacial chemistry, which can facilitate enhanced properties and performance. In this context, herein, novel lead-free piezoelectric materials (1-x)Ba_0.95Ca_0.05Ti_0.95Zr_0.05O₃-(x)Ba_0.95Ca_0.05Ti_0.95Sn_0.05O₃, are reported, which are represented as (1-x)BCZT-(x)BCST, with demonstrated excellent properties and energy harvesting performance. The (1-x)BCZT-(x)BCST materials are synthesized by high-temperature solid-state ceramic reaction method by varying x in the full range (x = 0.00–1.00). In-depth exploration research is performed on the structural, dielectric, ferroelectric, and electro-mechanical properties of (1-x)BCZT-(x)BCST ceramics. The formation of perovskite structure for all ceramics without the presence of any impurity phases is confirmed by X-ray diffraction (XRD) analyses, which also reveals that the Ca²⁺, Zr⁴⁺, and Sn⁴⁺ are well dispersed within the BaTiO₃ lattice. For all (1-x)BCZT-(x)BCST ceramics, thorough investigation of phase formation and phase-stability using XRD, Rietveld refinement, Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and temperature-dependent dielectric measurements provide conclusive evidence for the coexistence of orthorhombic + tetragonal (Amm2 + P4mm) phases at room temperature. The steady transition of Amm2 crystal symmetry to P4mm crystal symmetry with increasing x content is also demonstrated by Rietveld refinement data and related analyses. The phase transition temperatures, rhombohedral-orthorhombic (T_R-O), orthorhombic- tetragonal (T_O-T), and tetragonal-cubic (T_C), gradually shift toward lower temperature with increasing x content. For (1-x)BCZT-(x)BCST ceramics, significantly improved dielectric and ferroelectric properties are observed, including relatively high dielectric constant ε_r ≈ 1900–3300 (near room temperature), ε_r ≈ 8800–12 900 (near Curie temperature), dielectric loss, tan δ ≈ 0.01–0.02, remanent polarization P_r ≈ 9.4–14 µC cm⁻², coercive electric field E_c ≈ 2.5–3.6 kV cm⁻¹. Further, high electric field-induced strain S ≈ 0.12–0.175%, piezoelectric charge coefficient d₃₃ ≈ 296–360 pC N⁻¹, converse piezoelectric coefficient ${(d_{33}^{\ast })}_{\mathrm{ave}}$≈ 240–340 pm V⁻¹, planar electromechanical coupling coefficient k_p ≈ 0.34–0.45, and electrostrictive coefficient (Q₃₃)_avg ≈ 0.026–0.038 m⁴ C⁻² are attained. Output performance with respect to mechanical energy demonstrates that the (0.6)BCZT-(0.4)BCST composition (x = 0.4) displays better efficiency for generating electrical energy and, thus, the synthesized lead-free piezoelectric (1-x)BCZT-(x)BCST samples are suitable for energy harvesting applications. The results and analyses point to the outcome that the (1-x)BCZT-(x)BCST ceramics as a potentially strong contender within the family of Pb-free piezoelectric materials for future electronics and energy harvesting device technologies.     

Radiation-curable prepreg composites

Advanced composites, specifically carbon-fiber-reinforced epoxies, are used extensively for a variety of demanding structural applications, primarily because of their high strength-to-weight and stiffness-to-weight ratios, corrosion resistance, and damage tolerance characteristics. Electron beam (EB) treatment can be used to produce useful physical and/or chemical changes in plastics and composites by initiating various polymerization and crosslinking reactions. The advantages of using EB rather than thermal curing for carbon-fiber-reinforced epoxy composites include curing at ambient temperature, reduced curing times, and fewer volatiles. An EB-curable carbon fiber-acrylated epoxy composite is being developed for various applications. The tensile properties of the 14-ply EB-cured epoxy laminate were comparable with the properties of the thermally cured laminates used in the aircraft industry. Research is continuing to develop resin formulations and select coupling agents to improve the compression properties of EB-cured laminates.