Multi-band piezoelectric vibration energy harvester for low-frequency applications

Microsystem Technologies - Piezoelectric Energy Harvester (PEH) is a promising technology for harvesting energy from low frequency ambient vibrations. To generate the power from these low-frequency...     

Polyacrylamide‐g‐alginate‐based electrically responsive hydrogel for drug delivery application: Synthesis,characterization, and formulation development

An electrically responsive hydrolyzed polyacrylamide‐grafted‐sodium alginate (H‐PAAm‐g‐SA)‐based membrane‐controlled transdermal drug delivery systems were developed and evaluated. The grafting reaction was confirmed by Fourier transform infrared spectroscopy, elemental analysis, and thermogravimetric analysis. On application of electric stimulus, the swollen H‐PAAm‐g‐SA hydrogel was deswelled in the vicinity of electrodes. The drug release was greater in the presence of electric stimulus when compared with passive diffusion, and it was found to be dependent on the applied electric current strength, concentration of H‐PAAm‐g‐SA copolymer in the reservoir, and cross‐link density of rate‐controlling membrane. A pulsatile pattern of drug release was observed when the electric stimulus was switched “on” and “off.” The skin histopathology study suggested that, after application of an electrical stimulus, changes were in the structure of stratum corneum. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Temporal and spectral characteristics of aerosol optical depths in a semi-arid region of southern India

The spectral and temporal variations of aerosol optical depths (AOD) observed over Anantapur (a semi-arid region) located in the Southern part of India are investigated by analyzing the data obtained from a Multiwavelength Solar Radiometer (MWR) during January 2005-December 2006 (a total of 404 clear-sky observations) using the Langley technique. In this paper, we highlighted the studies on monthly, seasonal and spectral variations of aerosol optical depth and their implications. The results showed seasonal variation with higher values during pre-monsoon (March-May) and lower in the monsoon (June-November) season at all wavelengths. The pre-monsoon increase is found to be due to the high wind speed producing larger amounts of wind-driven dust particles. The post-monsoon (December-February) AOD values decrease more at higher wavelengths, indicating a general reduction in the number of bigger particles. Also during the post-monsoon, direction of winds in association with high or low pressure weather systems and the air brings more aerosol content to the region which is surrounded by a number of cement plants, lime kilns, slab polishing and brick making units. The quantity of AOD values in pre-monsoon is higher (low during post-monsoon) for wavelength, such as shortwave infrared (SWIR) or near infrared (NIR), which shows that coarse particles contribute more compare with the sub-micron particles. The composite aerosols near the surface follow suit with the share of the accumulation mode to the total mass concentration decreasing from ~ 70% to 30% from post-monsoon to pre-monsoon. Coarse mode particle loading observed to be high during pre-monsoon and accumulation mode particles observed to be high during post-monsoon. The backward trajectories at three representative altitudes with source point at the observing site indicate a possible transport from the outflow regions into Bay of Bengal, southern peninsular India and Arabian Sea. The temporal variations of AOD, Angstrom wavelength exponent and precipitable water content over Anantapur have also been compared with those reported from selected locations in India.     

Rapid photokilling of gram-negative Escherichia coli bacteria by platinum dispersed titania nanocomposite films

Superior antimicrobial activity of 2 wt.% Pt-dispersed TiO₂ thin film was observed in photokilling Gram-negative Escherichia coli bacteria within 5 min irradiation (640 μW cm⁻², λ > 340 nm) from UV torch than bare TiO₂ film. Severe disruption of cell membrane has occurred over illuminated Pt-TiO₂ catalysts films coated with 100–300 μg powders per 5 cm² areas over sterilized glass slides. The Pt dispersion onto TiO₂ by impregnation–hydrogen reduction always exhibited better photokilling effect than Pt photodeposition, irrespective of Pt–TiO₂ dose and light exposure time. Similar trend in photoactivity difference between two Pt–TiO₂ catalysts is also observed in aqueous slurry because of the unlike surface structure of TiO₂ due to different annealing temperatures, size and nature of Pt particles dispersion onto TiO₂ photocatalysts.     

Analytical Models for the Design of Iron-Based Permeable Reactive Barriers

The preliminary design of iron-based permeable reactive barriers is often accomplished using analytic expressions for one-dimensional groundwater flow and contaminant transport. Typically, one or more of the governing processes is simplified or neglected to facilitate development of a tractable solution. This paper presents a set of improved design equations that include the effects of dispersion, finite domain boundary, sequential decay, and production processes, and increased flow through high conductivity barriers. When applied to realistic example problems, application of the expanded design equations typically results in the specification of a larger permeable reactive barrier thickness than obtained using conventional approaches.     

Hourly River Flow Forecasting: Application of Emotional Neural Network Versus Multiple Machine Learning Paradigms

Water Resources Management - Monitoring hourly river flows is indispensable for flood forecasting and disaster risk management. The objective of the present study is to develop a suite of hourly...     

Green Synthesis of Zinc Oxide Nanoparticles (ZnO NPs) for Effective Degradation of Dye,Polyethylene and Antibacterial Performance in Waste Water Treatment

At present, there is a vital need for river water purification by developing new approaches to eliminate bacterial biofilms, textile dyes, and Low-Density Polyethylene (LDPE) plastics that pose severe threats to human and environmental health. The current work put forward the construction of an eco-friendly green strategy to synthesize zinc oxide nanoparticles (ZnO NPs) using areca nut (Areca catechu) extract and their application to tackle the challenges in water purification. Prepared biogenic NPs were characterized by X-ray diffraction analysis (XRD), Fourier Transform Infra-Red (FT-IR), Energy Diffraction Spectroscopy (EDS), Scanning Electronic Microscopy (SEM), Transmission Electron Microscopy (TEM) analysis, confirmed the spherical shape in 20 nm and UV–vis spectroscopy. The characteristic absorption band exhibited at 326 nm confirmed the formation of ZnO NPs using UV–vis spectroscopy. Among all the tested bacterial pathogens, the E. coli at 50 µg/mL concentration showed the highest inhibition of biofilm activity, followed by the highest growth curve, cellular leakage, and potassium ion efflux. The ZnO NPs observed with photo-degradation of Rhodamine-B (Rh-B), Methylene Blue (MB), and Nigrosine dyes under sunlight irradiation at different time intervals. Finally, the photocatalytic activity of LDPE-ZnO NPs nanocomposite film showed the highest degradation under solar light irradiation were confirmed through photo-induced weight loss, SEM, FTIR, and MALDI-TOF analysis. This study demonstrates ZnO NPs exhibit efficacy against biofilm formation, degradation of photocatalytic textile dyes, and low-density LDPE film under solar light irradiation, which can be a step forward in water purification.