Effect of soil pH on sorption of salinomycin in clay and sandy soils

Salinomycin is polyether ionophore, commonly used in poultry industry for the prevention of coccidial infections and promotion of growth. A large amount of the administered antibiotic is excreted as parent compound, eventually reaching agricultural lands. This makes it imperative for researchers to understand the behavior of the compound in soil environment by conducting sorption-desorption studies. In this study, sorption of salinomycin was measured in four agricultural soils, a clay soil with low organic matter content (LOM), a clay soil with high organic matter content (HOM), a sandy soil with HOM, and a loamy sandy (LOM) soils, at three pH levels, namely 4, 7 and 9. Desorption studies was carried out using the batch equilibration technique. It was observed that more than 98% salinomycin was strongly sorbed by all soils, irrespective of the soil organic matter content or soil pH. The sorption of salinomycin to the sandy soil marginally increased as the pH decreased, while the sorption to the two clay soils marginally increased as the pH increased. Desorption of salinomycin with methanol over a 72 h period was < 0.2% of the amount added; however, it was > 70% with a phosphate buffer (pH 7). Since the phosphate buffer would mimic, to some extent, the quality of water flowing through field soils containing various salts, it was concluded that salinomycin could pose significant threats to both shallow ground water and surface water bodies.Key words: Salinomycin, sorption, pH, desorption, environmental pollution, phosphate buffer

Phonon transport at the nanoscale with applications to batteries and advanced thermal insulation

It has been almost three decades since Nanoscale Thermal Science and Engineering became a well-established research field. Various major breakthroughs in fundamental understanding of thermal transport (phonons, photons, and electrons) at the nanoscale have been achieved in these three decades; however, the impact of these fundamental insights has been primarily targeted toward microelectronics and thermoelectrics applications. In this paper we provide examples of other applications such as Lithium ion battery thermal management and building thermal insulation, where nanoscale thermal science has a significant role to play. We have used time domain thermoreflectance (TDTR) to measure thermal conductivity of Lithium ion battery cathode material. To understand the fundamentals of thermal transport in the cathode material we created a model cathode system as compared engineered samples using pulsed laser deposition technique. We also used 3-omega technique for the engineered system. We have also made highly insulating material using functionalized nanoparticles for building applications. Results show that surface functionalization has a huge impact on thermal conductivity of an assembly of nanoparticle

Nanofluid Optical Property Characterization: Towards Efficient Direct Absorption Solar Collectors

Suspensions of nanoparticles (i.e., particles with diameters \u3c 100 nm) in liquids, termed nanofluids, show remarkable thermal and optical property changes from the base liquid at low particle loadings. Recent studies also indicate that selected nanofluids may improve the efficiency of direct absorption solar thermal collectors. To determine the effectiveness of nanofluids in solar applications, their ability to convert light energy to thermal energy must be known. That is, their absorption of the solar spectrum must be established. Accordingly, this study compares model predictions to spectroscopic measurements of extinction coefficients over wavelengths that are important for solar energy (0.25 to 2.5 mu m). A simple addition of the base fluid and nanoparticle extinction coefficients is applied as an approximation of the effective nanofluid extinction coefficient. Comparisons with measured extinction coefficients reveal that the approximation works well with water-based nanofluids containing graphite nanoparticles but less well with metallic nanoparticles and/or oil-based fluids. For the materials used in this study, over 95% of incoming sunlight can be absorbed (in a nanofluid thickness \u3e= 10 cm) with extremely low nanoparticle volume fractions - less than 1 x 10(-5), or 10 parts per million. Thus, nanofluids could be used to absorb sunlight with a negligible amount of viscosity and/or density (read: pumping power) increase

Parametric Analysis of a Coupled Photovoltaic/Thermal Concentrating Solar Collector for Electricity Generation

The analysis of the combined efficiencies in a coupled photovoltaic (PV)/thermal concentrating solar collector are presented based on a coupled electrical/thermal model. The calculations take into account the drop in efficiency that accompanies the operation of PV cells at elevated temperatures along with a detailed analysis of the thermal system including losses. An iterative numerical scheme is described that involves a coupled electrothermal simulation of the solar energy conversion process. In the proposed configuration losses in the PV cell due to reduced efficiencies at elevated temperatures and the incident solar energy below the PV bandgap are both harnessed as heat. This thermal energy is then used to drive a thermodynamic power cycle. The simulations show that it is possible to optimize the overall efficiency of the system by variation in key factors such as the solar concentration factor, the band gap of the PV material, and the system thermal design configuration, leading to a maximum combined efficiency of similar to 32.3% for solar concentrations between 10-50 and a band-gap around 1.5-2.0 eV. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3514590

Enhanced Charge Carrier Transport in 2D Perovskites by Incorporating Single-Walled Carbon Nanotubes or Graphene

Two-dimensional (2D) organic-inorganic (hybrid) perovskites are considered promising candidates to replace conventional three-dimensional (3D) perovskites for solar cell applications as they have good resistance against moisture and UV light. However, the use of 2D perovskite is associated with a significant decrease in power efficiency resulting from their low photogenerated charge carrier density and poor charge transport. To improve power efficiency in 2D perovskites, highly crystalline films (near-single-crystal quality) of 2D perovskite need to be synthesized where the alignment of the inorganic perovskite components is controlled to have vertical alignment with respect to the contacts to improve charge transport. In this work, we explored strategies to overcome this limitation by integrating 2D perovskite with single-walled carbon nanotubes or graphene to enable more efficient extraction of charge carriers toward electric contacts. Longer carrier lifetimes were achieved after the incorporation of the carbon nanostructures in the films, and at the cell level, power efficiency increased by 2-fold

CMR Features in Cardiac Sarcoidosis

Sarcoidosis is a multisystemic disorder of unknown aetiology characterised by the formation of noncaseating epithelioid cell granuloma involving various organ systems. Cardiac involvement has an important prognostic factor as it can present with life-threatening arrythmias and sudden death. Here, we present a case of cardiac sarcoidosis in a 46-year-old gentleman who presented with nonspecific signs and symptoms. We also discuss diagnostic difficulties especially when cardiac involvement is the only clinical sign. In this case, cardiac magnetic resonance (CMR) played an important role in the diagnosis and followup of our patient

Nanofluid-Based Direct Absorption Solar Collector

Solar energy is one of the best sources of renewable energy with minimal environmental impact. Direct absorption solar collectors have been proposed for a variety of applications such as water heating; however the efficiency of these collectors is limited by the absorption properties of the working fluid, which is very poor for typical fluids used in solar collectors. It has been shown that mixing nanoparticles in a liquid (nanofluid) has a dramatic effect on the liquid thermophysical properties such as thermal conductivity. Nanoparticles also offer the potential of improving the radiative properties of liquids, leading to an increase in the efficiency of direct absorption solar collectors. Here we report on the experimental results on solar collectors based on nanofluids made from a variety of nanoparticles (carbon nanotubes, graphite, and silver). We demonstrate efficiency improvements of up to 5% in solar thermal collectors by utilizing nanofluids as the absorption mechanism. In addition the experimental data were compared with a numerical model of a solar collector with direct absorption nanofluids. The experimental and numerical results demonstrate an initial rapid increase in efficiency with volume fraction, followed by a leveling off in efficiency as volume fraction continues to increase

Vapor Generation in a Nanoparticle Liquid Suspension Using a Focused, Continuous Laser

This letter discusses experimentation with optically induced phase change in nanoparticle liquid suspensions-commonly termed nanofluids. Four different types of nanofluids at five concentrations were exposed to a similar to 120 mW, 532 nm laser beam to determine the minimum laser flux needed to create vapor. Laser irradiance was varied between 0-770 W cm(-2). While the experiments were simple, they involved many complex, interrelated physical phenomena, including: subcooled boiling, thermal driven particle/bubble motion, nanoparticle radiative absorption/scattering, and nanoparticle clumping. Such phenomena could enable novel solar collectors in which the working fluid directly absorbs energy and undergoes phase change in a single step. c 2009 American Institute of Physics. [doi: 10.1063/1.3250174

Applicability of Nanofluids in High Flux Solar Collectors

Concentrated solar energy has become the input for an increasing number of experimental and commercial thermal systems over the past 10-15 years [M. Thirugnanasambandam et al., Renewable Sustainable Energy Rev. 14 (2010)]. Recent papers have indicated that the addition of nanoparticles to conventional working fluids (i.e., nanofluids) can improve heat transfer and solar collection [H. Tyagi et al., J. Sol. Energy Eng. 131, 4 (2009); P. E. Phelan et al., Annu. Rev. Heat Transfer 14 (2005)]. This work indicates that power tower solar collectors could benefit from the potential efficiency improvements that arise from using a nanofluid working fluid. A notional design of this type of nanofluid receiver is presented. Using this design, we show a theoretical nanofluid enhancement in efficiency of up to 10% as compared to surface-based collectors when solar concentration ratios are in the range of 100-1000. Furthermore, our analysis shows that graphite nanofluids with volume fractions on the order of 0.001% or less are suitable for 10-100 MW(e) power plants. Experiments on a laboratory-scale nanofluid dish receiver suggest that up to 10% increase in efficiency is possible (relative to a conventional fluid)-if operating conditions are chosen carefully. Lastly, we use these findings to compare the energy and revenue generated in a conventional solar thermal plant to a nanofluid-based one. It is found that a 100 MW(e) capacity solar thermal power tower operating in a solar resource similar to Tucson, AZ, could generate similar to$ 3.5 million more per year by incorporating a nanofluid receiver. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3571565

Plants derived therapeutic strategies targeting chronic respiratory diseases: Chemical and immunological perspective

The apparent predicament of the representative chemotherapy for managing respiratory distress calls for an obligatory deliberation for identifying the pharmaceuticals that effectively counter the contemporary intricacies associated with target disease. Multiple, complex regulatory pathways manifest chronic pulmonary disorders, which require chemotherapeutics that produce composite inhibitory effect. The cost effective natural product based molecules hold a high fervor to meet the prospects posed by current respiratory-distress therapy by sparing the tedious drug design and development archetypes, present a robust standing for the possible replacement of the fading practice of poly-pharmacology, and ensure the subversion of a potential disease relapse. This study summarizes the experimental evidences on natural products moieties and their components that illustrates therapeutic efficacy on respiratory disorders