Threshold criteria for incipient sediment motion on an inclined bedform in the presence of oscillating-grid turbulence

Here, we report laboratory experiments to investigate the threshold criteria for incipient sediment motion in the presence of oscillating-grid turbulence, with the bed slope inclined at angles between the horizontal and the repose limit for the sediment. A set of nine mono-disperse sediment types was used with size ranges normally associated with either the hydraulically-smooth or transitional regimes. Measurements of the (turbulent) fluid velocity field, in the region between the grid and bedform's surface, were obtained using two-dimensional particle imaging velocimetry. Statistical analysis of the velocity data showed that the turbulence had a anisotropic structure, due to the net transfer of energy from the normal to the tangential velocity components in the near-bed region, and that the fluctuations were dominant compared to the secondary mean flow. The sediment threshold criteria for horizontal bedforms were compared with, and found to be in good qualitative agreement with the standard Shields curve. For non-horizontal bedforms, the bed mobility was found to increase with increasing bed slope, and the threshold criteria were compared with previously-reported theoretical models, based on simple force-balance arguments

Comparison of Methods for Isolating High Quality DNA and RNA from an Oleaginous Fungus Cunninghamella bainieri Strain 2a1

A number of protocols have been reported for efficient fungal DNA and RNA isolation. However, many of these methods are often designed for certain groups or morphological forms of fungi and, in some cases, are species dependent. In this report, we compared four published protocols for DNA isolation from a locally isolated oleaginous fungus, Cunninghamella bainieri strain 2a1. These protocols either involved the use of polyvinyl pyrrolidone (PVP), hexacetyltrimethylammonium bromide (CTAB) or without using PVB or CTAB. For RNA isolation, we tested two published protocols, one of which is based on TRI REAGENT (Molecular Research Center, USA) and another is simple method employing phenol for RNA extraction and LiCl for precipitation. We found that the protocol involving the use of CTAB produced the highest genomic DNA yield with the best quality compared to other protocols. In the presence of CTAB, unwanted polysaccharides were removed and this method yielded an average amount of 816 ± 12.2 µg DNA/g mycelia with UV absorbance ratios A260/280 and A260/230 of 1.67 ± 0.64 and 1.97 ± 0.23, respectively. The genomic DNA isolated via this protocol is also suitable for PCR amplification and restriction enzyme digestion. As for RNA isolation, the method involving phenol extraction and LiCl precipitation produced the highest yield of RNA with an average amount of 372 ± 6.0 µg RNA/g mycelia. The RNA appears to be relatively pure since it has UV absorbance ratios A260/280 and A260/230 of 1.89 ± 2.00 and 1.99 ± 0.03, respectively. Finally, we have demonstrated that this method could produce RNA of sufficient quality for RT-PCR that amplified a 600 bp fragment of ∆12-fatty acid desaturase gene in C. bainieri

Step by step procedures : degradation of polycyclic aromatic hydrocarbons in potable water using photo-Fenton oxidation process

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic compounds, composed of two or more fused benzene rings and abundantly found in mixed-use areas. Mixed-use areas consist of dense population, urbanization, industrial and agricultural activities. River pollution are common in mixed-use areas and 98% of Malaysia's fresh water supply originates from surface water. The biological degradation, adsorption and advanced oxidation process were documented as the available PAHs treatment for water. To date, the application of the photo-Fenton oxidation process has been reported for the treatment of PAHs from contaminated soil (review paper), landfill leachate, municipal solid waste leachate, sanitary landfill leachate, aniline wastewater, ammunition wastewater and saline aqueous solutions. As for potable water, the application of Fenton reagent was aided with photo treatment or electrolysis not focusing on PAHs removal. • The presented MethodsX was conducted for PAHs degradation analysis in potable water samples using photo-Fenton oxidation process. • The designed reactor for batch experiment is presented. • The batch experiment consists of parameters like concentration of 17 USEPA-PAHs in the prepared aqueous solution (fixed variable), reaction time, pH and molarity ratio of hydrogen peroxide (H2O2): ferrous sulfate (FeSO4)

Characteristics of Low Reynolds Number Shear-Free Turbulence at an Impermeable Base

Shear-free turbulence generated from an oscillating grid in a water tank impinging on an impermeable surface at varying Reynolds number 74≤Rel≤570 was studied experimentally, where the Reynolds number is defined based on the root-mean-square (r.m.s) horizontal velocity and the integral length scale. A particular focus was paid to the turbulence characteristics for low Rel<150 to investigate the minimum limit of Rel obeying the profiles of rapid distortion theory. The measurements taken at near base included the r.m.s turbulent velocities, evolution of isotropy, integral length scales, and energy spectra. Statistical analysis of the velocity data showed that the anisotropic turbulence structure follows the theory for flows with Rel≥117. At low Rel<117, however, the turbulence profile deviated from the prediction where no amplification of horizontal velocity components was observed and the vertical velocity components were seen to be constant towards the tank base. Both velocity components sharply decreased towards zero at a distance of ≈1/3 of the integral length scale above the base due to viscous damping. The lower limit where Rel obeys the standard profile was found to be within the range 114≤Rel≤116

Ability of Ganoderma lucidum mycelial pellets to remove ammonia and organic matter from domestic wastewater

In this study, we explored the ability of wild-Serbian Ganoderma lucidum mycelial pellets (GLMPs) in treating synthetic domestic wastewater in a batch reactor under various operating conditions. The GLMPs produce non-hazardous by-products, are environmentally sustainable and able to produce in mass bulk with consistent quality. Riding on the highly efficient of treatment of industrial (textile) wastewater using GLMPs, similar high efficiency is foreseen for domestic wastewater as a green alternative treatment process. The optimal performance of GLMPs in similar synthetic domestic wastewater with a Carbon-to-Nitrogen (C/N) ratio of 16.7:1 was evaluated under three operational conditions. The C/N ratio was chosen based on the urban domestic wastewater characteristic during high peak flow with an initial Chemical Oxygen Demand (COD) of 533 mg/L and ammonia–nitrogen (NH3–N) content of 30 mg/L. The operational parameters of agitation speed (0 rpm, 25 rpm, 50 rpm, and 100 rpm), environmental temperature (25 °C, 30 °C, 35 °C, and 40 °C), and GLMP inoculum percentage (GIP) (0%, 0.25%, 0.50%, 0.75%, and 1.00%) were chosen for the experiment. In the experiment, the agitation speed of 100 rpm and the environmental temperature of 25 °C showed the best performance of the GLMPs within 15 h of retention time with a percentage removal of 92.9% for COD and 93.8% for NH3–N. Furthermore, a high volume of GIP in the batch reactor had an insignificant impact on the performance in the same concentration of wastewater, and 0.25% GIP was the volume used to treat the domestic wastewater