Numerical modelling of horizontal sediment-laden jets

Sediment-laden turbulent flows are commonly encountered in natural and engineered environments. It is well known that turbulence generates fluctuations to the particle motion, resulting in modulation of the particle settling velocity. A novel stochastic particle tracking model is developed to predict the particle settling out and deposition from a sediment-laden jet. Particle velocity fluctuations in the jet flow are modelled from a Lagrangian velocity autocorrelation function that incorporates the physical mechanism leading to a reduction of settling velocity. The model is first applied to study the settling velocity modulation in a homogeneous turbulence field. Consistent with basic experiments using grid-generated turbulence and computational fluid dynamics (CFD) calculations, the model predicts that the apparent settling velocity can be reduced by as much as 30 % of the stillwater settling velocity. Using analytical solution for the jet mean flow and semi-empirical RMS turbulent velocity fluctuation and dissipation rate profiles derived from CFD predictions, model predictions of the sediment deposition and cross-sectional concentration profiles of horizontal sediment-laden jets are in excellent agreement with data. Unlike CFD calculations of sediment fall out and deposition from a jet flow, the present method does not require any a priori adjustment of particle settling velocity.     

Indigo carmine removal by charcoal from rice bran as an agricultural by-product

On the utilization of agricultural by-product, charcoal from rice bran was produced. The adsorption characteristics of indigo carmine onto charcoals from rice bran were investigated by the batch method. The yield and surface area of charcoal were decreased and increased with increase of carbonization temperature, respectively. The removal ratio of indigo carmine was high with the charcoal carbonized at higher temperature. In the relationship between the amount of indigo carmine adsorbed and the square root of elapsed time, a good linearity was recognized. The kinetic constant of adsorption removal for indigo carmine was rapid in the charcoal carbonized at higher temperature. The adsorption characteristics for indigo carmine removal by charcoal from rice bran were dominated by the value of their surface area.     

Determination of three endocrine disrupting chemicals,triclosan, 4-n-nonylphenol,and di-n-butyl phthalate using stir bar sorptive extraction in samples of different matrices

Three endocrine disrupting chemicals (EDCs), triclosan (TCS), 4-n-nonylphenol (4-n-NP), and di-n-butyl phthalate (DBP) were determined using stir bar sorptive extraction (SBSE) along with high-performance liquid chromatography/photodiode array detection (HPLC/DAD). Benzyl butyl phthalate was used as an internal standard. The targeted analytes could be rapidly determined with limits of quantification (LOQ) ranging from 4.1 (DBP), 10 (TCS), to 34 (4-n-NP)?µg?L^?1 in real samples such as bottled waters, personal care products, soaps, lotions, and urine. The results show that the developed analytical scheme is solvent-saving, efficient, and capable of fast screening samples for these common EDCs.     

Correlation between lead and iron in children's blood in Jordan

A total of 200 Jordanian children were classified into two groups: 100 Fe replete and 100 Fe deficient with ages ranging between 3.0 and 12.0 years (6.9 ± 2.7 years). All participants were chosen according to proper selection criteria followed by the sample collection: the samples were analyzed for hemoglobin and red blood cells; ferritin, an immunoassays-based instrument; and levels of Pb, Cu, and Zn. There were no significant differences between genders regarding Fe-deficiency (p = 0.57 and χ2 = 0.33), with a significant association of younger individuals (3.0–9.1 years) with Fe-deficiency (p < 0.05 and χ2 = 22.7).

In addition, there is a significant positive correlation between Fe-deficiency with blood levels of Pb, Cu, and Zn (p < 0.05), (r = 0.43, 0.35, and 0.42, respectively) as compared to control group, this findings supported, by comparing the levels of the examined metals in both groups, in individuals whom close to heavy metals source (highway traffic or oil gas station), and found that the mean of the heavy metals level in close Fe-deficient group higher than in close Fe-replete group.     

Detection and quantitation of trace levels of low molecular weight halocarbons (LMHs) associated with commercial sodium humate

Examination of vapor above commercial sodium humate and above 10wt% aqueous humate solution by gas chromatography (GC) revealed the presence of chloroform and trichloroethylene. Further examination of the aqueous humate by the purge and trap procedure confirmed the association of chloroform and trichloroethylene with the humate. GC/mass spectrometry analyses of methylene chloride extract of the humate established the association of LMHs with the humate. Improved headspace capillary GC technique showed that the humate contained not only chloroform, trichloroethylene but several other LMHs in the range 190 to 4000ng·kg^‐1.     

Rapid liquid chromatographic analysis of Metoclopramide in pharmaceutical preparations

A sensitive, accurate and reproducible method for the analysis of metoclopramide, a gastrointestinal drug, has been described. An isocratic HPLC elution method was employed which requires about 10 minutes to be performed. The concentration of metoclopramide hydrochloride preparations was found to be 95.1 ±0.3% and 94.21 ±0.25% in tablet and injection formulations, respectively.     

A model for approving and controlling sea water pollution for recreational activity

A model for assessing approval of a beach for recreational water activity was proposed. The model is based upon a sanitary survey together with intensive microbiological monitoring three times a day, five times a week for a month. In highly populated areas, continuous surveys once a day, five days a week are needed in order to assure the cleanliness and safety of these beaches.

Due to our intensive monitoring system, we can assure that Tel‐Aviv has one of the cleanest beaches near a metropolitan area in the Mediterranean Sea.     

Charge‐transfer chromatographic study of the interaction of commercial pesticides with hydroxypropyl‐β‐cyclodextrin

The interaction between 33 commercial pesticides with hydroxypropyI‐β‐cyclodextrin (HPBCD) was studied by charge‐transfer reversed‐phase thin‐layer chromatography using aqueous sodium chloride solutions as eluents. Each pesticide interacted with HPBCD, their lipophilicity linearly decreased with increasing HPBCD concentration, the pesticide ‐ HPBCD complex (probably inclusion complex) always being more hydrophilic than the uncomplexed pesticide. In many cases the retention of pesticide increased with increasing concentration of salt in the eluent. This effect can be tentatively explained by the suppression of the dissociation of the polar groups in the solute molecules resulting in increased apparent lipophilicity. No significant correlation was found between lipophilicity and complex stability or between salting‐out effect and lipophilicity, that is other than hydrophobic forces are involved in the pesticide ‐ HPBCD interaction.     

Effects of the Ellagic acid on the N‐Acetyltransferase activity and Acetylation of 2‐aminofluorene in the rat

The effects of the ellagic acid on the in vitro and in vivo acetylation of 2‐aminofluorene were investigated in male Sprague‐Dawley rats. For in vitro examination, cytosols with or without ellagic acid co‐treatment showed different percentage of 2‐aminofluorene acetylation. For in vivo examination, pre‐treatment of male rats with ellagic acid (10 mg/kg) 24h prior to the administration of 2‐aminofluorene (50 mg/kg) resulted in a 26% and 29%, respectively, decrease in the urinary and fecal recovery of N‐acetyl‐2‐aminofluorene, and a 37% decrease in the metabolic clearance of 2‐aminofluorene to N‐acetyl‐2‐aminofluorene. This is the first demonstration that ellagic acid decrease the N‐acetylation of carcinogens in vitro and in vivo.     

Potentiometric studies of mixed complexes of cobalt(II) and copper(II) with l‐Asparagine and adenine

A potentiometric titration technique has been used to determine the stability constants for the various complexes of Co(II) and Cu(II) with L‐asparagine and from DNA base, e.g. adenine. Stability constants of ternary systems have been evaluated by the method suggested by Irwing‐Rossotti. In addition, the conditional constants were calculated as a function of pH. The maximum values of the conditional formation constants were found to be in accordance with the mixed‐ligand complex formation constants in a determined pH region. Furthermore, the molar fractions of different species from mixed complexes were calculated by means of formation constants. The values of stability constants of mixed‐ligand complexes at 25°C are as follows: log K= 5.25 for Co(II)‐L‐asparagine‐adenine; log K= 9.30 for Cu(II)‐L‐asparagine‐adenine. The ionic strength was kept constant at I = 0.20 with NaClO₄.