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In order to investigate the effect of pulse width and solvent on the nonlinear properties of metal nanostructures, silver nanowires were fabricated in a direct current electric field (DCEF) using a solid-state ionic method and characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The nonlinear refractive index ( γ) of silver nanowires suspended in ethanol was measured using the Z-scan technique and laser radiation of various (femto-, pico-, and nanosecond) pulse durations. Experimental results indicated that silver nanowires have obvious positive refractive nonlinearities and γ (the Kerr-induced self-focusing) increases as the pulse duration increases from 7.4×10−8 cm2/GW at 110 fs to 1.6×10−4 cm2/GW at 8 ns, due to the additional influence of the atomic reorientational Kerr effect in the case of longer pulses. Due to the solvent dependence of the nonlinear behavior of the silver nanowires, the nonlinear absorption and refraction of silver nanowires suspended in de-ionized water are smaller than those of silver samples suspended in ethanol. The thermal nonlinearities are insignificant in our experimental conditions. [ABSTRACT FROM AUTHOR]

This article is devoted to the description of the scattering of light by one spheroid. The size of the spheroid is large enough (up to 40 μm, size parameter equal to about 200) to be of practical interest for various applications in particle sizing techniques. This point is exemplified by a discussion on the sensitivity of the rainbow (first order) to the particle shape. As a result, the validity of the Mo¨bius formula is examined. [Copyright &y& Elsevier]

Abstract: Methods to synthesize magnetic Fe3O4 nanoparticles and to modify the nanoparticle surface are presented in this paper. In these methods, Fe3O4 nanoparticles were prepared by co-precipitation, and the aging of nanoparticles was improved by applied magnetic field. The obtained nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). Thereafter, to enhance the compatibility between nanoparticles and water, an effective surface modification method was developed by grafting acrylic acid onto the nanoparticle surface. FT-IR, XRD, transmission electron microscopy (TEM), and thermogravimetry (TG) were used to characterize the resultant sample. The testing results indicated that the polyacrylic acid chains have been covalently bonded to the surface of magnetic Fe3O4 nanoparticles. The effects of initiator dosage, monomer concentration, and reaction temperature on the characteristics of surface-modified Fe3O4 nanoparticles were investigated. Moreover, the Fe3O4-g-PAA hybrid nanoparticles were dispersed in water to form ferrofluids (FFs). The obtained FFs were characterized by UV–vis spectrophotometer, Gouy magnetic balance and laser particle-size analyzer. The testing results showed that the high-concentration FF had excellent stability, with high susceptibility and high saturation magnetization. The rheological properties of the FFs were also investigated using a rotating rheometer. [Copyright &y& Elsevier]

Abstract: Fe3O4 magnetic nanoparticles (MNPs) were prepared by the coprecipitation of Fe2+ and Fe3+ using ammonium hydroxide (NH4OH) as precipitating agent. Transmission electronic microscopy (TEM) showed that the particle-size is around 10 nm. X-ray powder diffraction (XRD) indicated the sole existence of inverse cubic spinel phase of Fe3O4. The surface of MNPs was coated with oleate sodium as the primary layer and polyethylene glycol 4000 (PEG-4000) as the secondary layer to improve the stability of water-based ferrofluids (FFs). The dosages of oleate sodium and PEG-4000 were found to have an important effect on increasing the solid content. Gouy magnetic balance showed that the saturation magnetization could be as high as 1.44×105 A/m. Laser particle-size analyzer determined the aggregate size in FFs. The Fe3O4 MNPs did not change through the preparation of FFs. Differential scanning calorimetry–thermogravimetry (DSC–TG) and Fourier transform infrared spectroscopy (FT-IR) analysis showed existence of two distinct surfactants on the particle surface. The concentrated and diluted FFs were characterized by UV-vis spectrophotometer and excellent stability was found. The rheological measurements indicated that viscosity increased with the increase of solid content and applied magnetic field, but decreased with the increase of temperature. The FFs showed the non-Newtonian behavior of shear-thinning when the solid content was high. The mechanical properties of polyvinylalcohol (PVA) thin film can be greatly improved by adding FFs. [Copyright &y& Elsevier]

Abstract: The use of microfiltration (MF) or ultrafiltration (UF) prior to reverse osmosis (RO) process for reuse of reclaimed water is becoming increasingly attractive. In this work, a secondary municipal effluent was treated by a pilot-scale continuous filtration system with an innovative polyvinylidene fluoride (PVDF) MF membrane prepared via thermally induced phase separation (TIPS) method. The study showed that the MF system was operated under low normalized trans-membrane pressure (substantially below 40kPa) and high permeate flux (52–60L/m2/h). The MF system was able to treat the secondary effluent of unstable quality with good system stability. The membrane''s permeability was easily recovered by chemical enhanced backwash (CEB) at a low effective chorine concentration (300 or 500mg/L). The membrane exhibited excellent mechanical strength and strong chemical resistance throughout the investigation. The treated water from the MF system exhibited stable quality with turbidity less than 0.05NTU, 15-minute silt density index (SDI15) less than 3 and chemical oxygen demand (CODCr) less than 15mg/L. The treated water quality completely met the quality requirement of RO feed water. This work demonstrated the feasibility of using the innovative MF membrane prior to RO for reuse of the secondary municipal effluent. [Copyright &y& Elsevier]

Abstract: A lumped parameter model of a silica gel–water adsorption chiller driven by solar energy was introduced for the operating characteristics investigation. Matlab–Simulink, as a high-performance computing and programming tool, was used to simulate the operating characteristics of the chiller. Effects of the hot water tank capacity, the cycle time and the initial hot water temperature on the performance of the chiller were analyzed when the chiller was driven by a stable heat source and solar energy respectively. The simulation results indicated that when the chiller was driven by solar energy, the open circulation of the hot water with a short cycle time and the closed circulation of hot water with a longer cycle time were better. A proposal was also provided for the chiller driven by solar energy to work under the optimum working conditions, such as hot water circulation mode, cycle time and initial temperature. [Copyright &y& Elsevier]

Abstract: Impact assessment of contaminants in soil is an important issue in environmental quality study and remediation of contaminated land. A random amplified polymorphic DNA (RAPD) ‘fingerprinting’ technique was exhibited to detect genotoxin-induced DNA damage of plants from heavy metal contaminated soil. This study compared the effects occurring at molecular and population levels in barley seedlings exposed to cadmium (Cd) contamination in soil. Results indicate that reduction of root growth and increase of total soluble protein level in the root tips of barley seedlings occurred with the ascending Cd concentrations. For the RAPD analyses, nine 10-base pair (bp) random RAPD primers (decamers) with 60–70% GC content were found to produce unique polymorphic band patterns and subsequently were used to produce a total of 129 RAPD fragments of 144–2639 base pair in molecular size in the root tips of control seedlings. Results produced from nine primers indicate that the changes occurring in RAPD profiles of the root tips following Cd treatment included alterations in band intensity as well as gain or loss of bands compared with the control seedlings. New amplified fragments at molecular size from approximately 154 to 2245bp appeared almost for 10, 20 and 40mgL−1 Cd with 9 primers (one–four new polymerase chain reaction, (PCR) products), and the number of missing bands enhanced with the increasing Cd concentration for nine primers. These results suggest that genomic template stability reflecting changes in RAPD profiles were significantly affected and it compared favourably with the traditional indices such as growth and soluble protein level at the above Cd concentrations. The DNA polymorphisms detected by RAPD can be applied as a suitable biomarker assay for detection of the genotoxic effects of Cd stress in soil on plants. As a tool in risk assessment the RAPD assay can be used in characterisation of Cd hazard in soil. [Copyright &y& Elsevier]