Foundations of mechanism design: A tutorial Part 2-Advanced concepts and results

Mechanism design, an important tool in microeconomics, has found widespread applications in modelling and solving decentralized design problems in many branches of engineering, notably computer science, electronic commerce, and network economics. In the first part of this tutorial on mechanism design (Garg et al 2008), we looked into the key notions and classical results in mechanism design theory. In the current part of the tutorial, we build upon the first part and undertake a study of several other key issues in mechanism design theory.     

Effect of distillery sludge on seed germination and growth parameters of green gram (Phaseolus mungo L.)

Experiments were carried out to study the effect of distillery sludge amendments with garden soil (10, 20, 40, 60, 80 and 100%) on seed germination and growth parameters of Phaseolus mungo L. Germination percentage and index values decreased with rise in sludge concentration. Soil amended with 10% (w/w) sludge showed favorable growth while >10% was inhibitory for plant growth. Soil amended with 10% (w/w) distillery sludge induced the growth in root length, shoot length, number of leaves, biomass, photosynthetic pigment, protein and starch while 20% (w/w) sludge amended soil had variable effects on the root, shoot, leaves and nodules of P. mungo L. At concentrations (>40%) reduced all the growth parameters, viz., root length, shoot length, number of leaves, biomass, photosynthetic pigment, protein and starch of P. mungo. Malondialdehyde (MDA) product of lipid peroxidation was also enhanced in both root and leaves of sludge amended soil grown P. mungo at all the sludge amendments and exposure periods. A coordinated increase in cysteine, non-protein thiol and ascorbic acid antioxidants was up to 40 days of growth. After this period a decrease was observed. The N, P, K and Mg accumulation followed the order shoot>leaf>root. Calcium accumulation was highest in the upper part of the plants (including shoot and leaves). Furthermore, heavy metals content were also increased in different parts of P. mungo grown on increasing concentration of sludge amended garden soil with time. Zinc and copper accumulation was maximum versus other heavy metals. Based on these studies, sludge having concentrations < or =10% (w/w) can be applied as a fertilizer.     

Impact of measurement precision and noise on superresolution image reconstruction

The performance of uniform and nonuniform detector arrays for application to the PANOPTES (processing arrays of Nyquist-limited observations to produce a thin electro-optic sensor) flat camera design is analyzed for measurement noise environments including quantization noise and Gaussian and Poisson processes. Image data acquired from a commercial camera with 8 bit and 14 bit output options are analyzed, and estimated noise levels are computed. Noise variances estimated from the measurement values are used in the optimal linear estimators for superresolution image reconstruction.     

Fabrication of AMoO4 (A = Ba, Sr) film on Mo substrate by solution reaction assisted ball-rotation

Alkaline earth molybdates, such as BaMoO₄ and SrMoO₄, films have been successfully fabricated on a Mo metal substrate in AOH (A = Ba, Sr) solutions by a ball-rotation-assisted solution reaction, at room temperature. The dissolution of Mo was mainly controlled by the concentration of the H₂O₂ oxidizing agent and ball-rotation to form MoO₄²⁻ in the solution. AMoO₄ was deposited on the substrate by the reaction between MoO₄²⁻ and A²⁺ ions without any high energy or high-temperature treatment. Also, the mass transport of alkaline earth ions onto the solid/solution interface was improved as a result of the vigorous solution agitation by the ball-rotation. Therefore, the rate of deposition of the AMoO₄ films was accelerated by the ball-rotation. A decrease in the grain size of the film was observed with an excessive ball-rotation.     

Effects of Additives on the Pressure-Assisted Densification and Properties of Silicon Carbide

The densification of silicon carbide (SiC) was studied using a variety of additives (Al, AlN, Al₂O₃, B₄C, C, Si₃N₄, and Y₂O₃). The onset of densification of SiC with small amounts of additives occurred at temperatures between 1500° and 1900°C with 28 MPa applied pressure. Al, B₄C, and C promoted densification, while N (added as AlN or Si₃N₄) retarded sintering. A 96.75 wt% SiC–2 wt% Al–1 wt% C–0.25 wt% B₄C starting composition yielded the same percent of theoretical density (in the range of 70%–90% theoretical density) 400°C lower than a 95 wt% SiC–5 wt% AlN material. Yttria additions promoted intergranular fracture, which increased the single-edged precracked beam fracture toughness. The appropriate selection and amount of additives allowed for the tailoring of grain size and intergranular fracture, thus controlling the mechanical properties. While oxygen was present in all materials containing aluminum, the incorporation of additional oxygen as alumina resulted in reduced sintering activity compared with Al metal. Corrosion resistance decreased in both HF and NaOH solutions at 80°C for materials containing a grain boundary phase.     

Synthesis of copper nanoparticles by electrolysis of DNA utilizing copper as sacrificial anode

Copper nanoparticles have been synthesized by anodic oxidation through a simple electrolysis process employing de-oxy ribonucleic acid (DNA) as electrolyte. Platinum was taken as cathode and copper as anode. The applied voltage was 4 V and the electrolysis was performed for duration of 1 h. The copper nanoparticles were prepared in situ from the electron beam irradiation on residues of electrolyte consisting of DNA and copper particles: DNA (Cu) complexes. The size of the nanoparticles ranges between 5-50 nm. A tentative explanation has been given for the formation of copper nanoparticles.     

Molecular interactions alter clay and polymer structure in polymer clay nanocomposites.

In this work, using photoacoustic Fourier transform infrared spectroscopy (FTIR) we have studied the structural distortion of clay crystal structure in organically modified montmorillonite (OMMT) and polymer clay nanocomposites (PCN). To study the effect of organic modifiers on the distortion of crystal structure of clay, we have synthesized OMMTs and PCNs containing same polymer and clay but with three different organic modifiers (12-aminolauric acid, n-dodecylamine, and 1,12-diaminododecane), and conducted the FTIR study on these PCNs. Our previous molecular dynamics (MD) study on these PCNs reveals that significant nonbonded interactions (van der Waals, electrostatic interactions) exist between the different constituents (polymer, organic modifier, and clay) of nanocomposites. Previous work based on X-ray diffraction (XRD) and differential scanning calorimetry (DSC) on the same set of PCNs shows that crystallinity of polymer in PCNs have changed significantly in comparison to those in pristine polymer; and, the nonbonded interactions between different constituents of PCN are responsible for the change in crystal structure of polymer in PCN. In this work to evaluate the structural distortion of crystal structure of clay in OMMTs and PCNs, the positions of bands corresponding to different modes of vibration of Si-O bonds are determined from the deconvolution of broad Si-O bands in OMMTs and PCNs obtained from FTIR spectra. Intensity and area under the Si-O bands are indicative of orientation of clay crystal structures in OMMTs and PCNs. Significant changes in the Si-O bands are observed from each vibration mode in OMMTs and PCNs containing three different organic modifiers indicating that organic modifiers influence the structural orientation of silica tetrahedra in OMMTs and PCNs. Deconvolution of Si-O bands in OMMTs indicate a band at approximately 1200 cm(-1) that is orientation-dependent Si-O band. The specific changes in intensity and area under this band for OMMTs with three different organic modifiers further confirm the change in structural orientation of silica tetrahedra of OMMTs by organic modifiers. Thus, from our work it is evident that organic modifiers have significant influence on the structure of polymer and clay in PCNs. It appears that in nanocomposites, in addition to strong interactions at interfaces between constituents, the structure of different phases (clay and polymer) of PCN are also altered, which does not occur in conventional composite materials. Thus, the mechanisms governing composite action in nanocomposites are quite different from that of conventional macro composites.     

Efficacy of seagrass <Emphasis Type="Italic">Cymodocea rotundata</Emphasis> beads on the removal of excessive nutrients in shrimp aquaculture wastewater

The aim of present study is to ascertain the effects of pH, retention time, biomass dosage in beads and beads density on nutrients (Phosphate and Nitrate) uptake efficiency of seagrass Cymodocea rotundata beads in aquaculture effluent. This study was carried out in shake flask at different pH viz. 5; 6; 7; 8 and 9, and different retention time such as 30; 60; 90 and 120 min. The seagrass biomass dosage was tested with 0.1; 0.5 and 1.0 g and beads density of 25; 50; 75; 100; 125 and 150 nos. These results revealed that the optimum pH for maximum uptake of phosphate and nitrate was 7. The overall maximum nutrient uptake was noticed in 50 number beads density where the nitrate concentration decreasing from 2.05 to 0.51 μmol/L and phosphate 1.203 to 0.31 μmol/L. On considering the effects of pH, biomass and retention time, the maximum nitrate reduction (3.85 μmol/L) was found at pH 7 in 120 min at 0.1 g biomass dosage. The high phosphate removal (0.68 μmol/L) was found at pH 7 in 120 min at 0.1 g biomass dosage. Whereas in case of biomass dosage in beads, the maximum nutrients removal were noticed at 0.1 g among the dosage tested.     

Influence of an oxygenated additive on emission of an engine fueled with neat biodiesel

Biodiesel obtained from mustard seed is found to be a promising alternative for petroleum diesel fuel owing to its similarity in physical and chemical properties. In this work, TiO₂ nano-fluid which acts as an oxygen buffer during combustion was added to mustard oil biodiesel (MOBD) to study its effect on emission characteristics of MOBD. TiO₂ nano-fluid can provide high surface energy during the course of combustion and reduces the limitations of neat biodiesel. A four-stroke, multi-cylinder, water-cooled, diesel engine was used in the experiments and was fueled with diesel, neat MOBD and MOBD with TiO₂ nanoparticles at 100 ppm (MOBDT100), 200 ppm (MOBDT200) and 300 ppm (MOBDT300). Experimental results revealed that the TiO₂ nanoparticles had positive effect on the emission characteristics of MOBD as it acted as an oxidation buffer. MOBDT300 showed a reduction in HC, CO and smoke emissions as compared to pure MOBD. In addition, NO_x emissions were also reduced by the catalytic activity of the TiO₂ nanoparticles which reduce the peak combustion temperature. Therefore, TiO₂ nano-fluid had a positive effect on reducing the emissions associated with neat biodiesel.     

Intelligent optimization of renewable resource mixes incorporating the effect of fuel risk,fuel cost and CO2 emission

Power system planning is a capital intensive investment-decision problem. The majority of the conventional planning conducted since the last half a century has been based on the least cost approach, keeping in view the optimization of cost and reliability of power supply. Recently, renewable energy sources have found a niche in power system planning owing to concerns arising from fast depletion of fossil fuels, fuel price volatility as well as global climatic changes. Thus, power system planning is under-going a paradigm shift to incorporate such recent technologies. This paper assesses the impact of renewable sources using the portfolio theory to incorporate the effects of fuel price volatility as well as CO₂ emissions. An optimization framework using a robust multi-objective evolutionary algorithm, namely NSGA-II, is developed to obtain Pareto optimal solutions. The performance of the proposed approach is assessed and illustrated using the Indian power system considering real-time design practices. The case study for Indian power system validates the efficacy of the proposed methodology as developing countries are also increasing the investment in green energy to increase awareness about clean energy technologies.