Design Water Levels in Tidal River Systems under the Influence of Typhoons

Water levels in tidal rivers are subject to the influence of both fluvial and tidal factors. The interaction between these factors is rendered more complex in regions affected by typhoons, which typically result in the combined occurrence of heavy rainfall and high sea levels.
Previous studies have outlined an analytical approach for calculating design water levels based on dividing the fluvial and tidal series into a typhoon and a non-typhoon component. This paper illustrates the steps involved in the analytical approach and describes its application to drainage basins in Hong Kong.
The approach provides a practical means for calculating design water levels, and is recommended for final design purposes. The results of using the full analysis may be approximated by using a sub-set of analytical results, and should prove satisfactory for the purposes of outline design.     

Protocatechuic acid ozonation in aqueous solutions

The oxidation of protocatechuic acid with ozone in aqueous solution has been studied varying the temperature, pH, ozone partial pressure and initial acid concentration. A stoichiometric ratio of 2 mol of ozone consumed per mol of protocatechuic acid reacted is deduced from homogeneous experiments in a discontinuous tank reactor.In the ozonation experiments, the influence of the operating variables was established and the kinetic regime of ozone absorption was shown to be fast and pseudo m-order with respect to ozone, except at pH 2, when the reaction develops in the moderate kinetic regime. After applying a mass transfer with chemical reaction model, the reaction orders are deduced and the kinetic rate constants are determined as a function of pH and temperature. A modified Arrhenius expression is proposed to correlate them.     

Compartment tests of polyurethane foam seating assemblies

Data from compartment tests of polyurethane foam seating assemblies are reported. Results show that the behavior of such assemblies during fires is strongly dependent on the type and position of interliners and upholstery fabrics. An incidental comparison of peak rate of heat release obtained in a compartment test with a predictive model equation is made and selected data from the tests are presented.     

Geomechanical model simulation for the varied rock formations of the Kadana dam foundation,Gujarat, India

Bulletin of Engineering Geology and the Environment - Precambrian layered rocks consisting of quartzites, phyllites and metagreywackes of the Aravallis having a large variation in thickness,...     

Sorption of benzenesulfonates by weak base anion exchange resins

Weak base phenol formaldehyde anion exchange resins were found to have an excellent capacity for removing the anionic organic species benzenesulfonate (BS), p-toluenesulfonate (PTS) and dodecylbenzenesulfonate (DBS) from pH 2 and 4 solutions. The capacity for DBS was generally greater than that of activated carbon and significantly greater than that of a polystyrene-divinylbenzene resin with no ion exchange functional groups. The maximum capacity of the weak base resins appeared to be limited by the exchange capacity of the resin. The mechanism of removal was strongly indicated as being either ion exchange at the amine functional groups in the acid form, or uptake of a proton by the amine groups in the free base form with the organic anion as the associated counter ion. Increasing concentrations of Cl⁻ decreased the amount of organic anion that could be sorbed.The swelling of one of the resins, Duolite A-7, also had a marked effect on its sorption capacity. The pores of the acid chloride or acid organic anion form of the resin were apparently larger than those of the free base form; thus, as conversion of the resin to the acid form took place, a greater amount of uptake was observed. The effect of swelling on the capacity of Duolite S-37 was much less, apparently owing to its larger pore structure, but its capacity for DBS at low pH was lower than that for A-7 because of its lower nitrogen content. Also, BS and DBS were easily removed from the weak base resins by washing them with NaOH. Four bed volumes of 1 m NaOH gave essentially complete regeneration of BS saturated A-7.     

Dynamic analysis and optimal feedback control synthesis applied to biological waste treatment

The dynamics and optimal feedback control of biological waste treatment processes are examined. Modern feedback control theory is applied and results are obtained for both proportional and proportional plus integral control. A dynamic mathematical model of the system is developed by employing a Monod kinetic model, which is modified to account for endogenous metabolism, and a complete mixing flow model in the growth chamber. The feedback control is implemented via the flow rate so as to maintain desired effluent concentrations. External disturbances which cause changes in substrate concentration and/or cell concentration are considered and optimal control effort is applied. Results are also presented for impulse and step changes in the influent substrate concentration. It is found that by changing the values of the weighting factors in the objective function, it is possible to obtain good control of either the effluent substrate concentration or cell concentration.     

Toxicity bioassay of heavy metals in water using Tetrahymena pyriformis

The toxicities of five heavy metal compounds on the survival of the ciliated protozoan Tetrahymena pyriformis were determined. Three-day old cultured cells were exposed to five concentrations of each test compound in one or more of three water series; distilled, soft, and hard water. A culture of each sample was placed in a plastic petri dish and covered with mineral oil to prevent evaporation. The cells were counted initially, then again at 0·5 h, 1 h, 2 h, 1 day, 2 days, 3 days, and on the fourth day. Lethal threshold concentrations and tolerance limit medians were determined by graphic methods. On a weight bases cadmium was most toxic, followed in decreasing toxicity by mercury, cobalt, zinc, and lead. Compared to similar fish data, all heavy metals were more toxic to T. pyriformis except lead. The toxicity of lead in soft versus hard water exemplified an antagonistic effect with greater than seven times the amount of lead necessary in hard water to produce comparable mortality as lead in soft water. On the other hand, the toxicity of mercury is about twice as great in hard water as in soft water (a synergistic effect). T. pyriformis appears to be a more sensitive indicator than fish of heavy metal contamination of water. T. pyriformis bioassay should prove a good means of determining the existence of many water pollutants.     

The development of macrolayer thickness of water in the pool boiling regime

ABSTRACT

The main purpose of this study is to analyse the phenomenon of pool boiling in water over a horizontally placed copper tube heater of 28?mm diameter. The experiment has been carried out to observe the bubble growth and departure characteristics for the heat flux range up to 40,000?W/m². The entire process is being recorded by a digital camera at different time intervals. The measured parameters have been used to determine the initial layer thickness, macro layer thickness and critical heat flux and validated with models proposed in the literature.     

Classic and novel brominated flame retardants (BFRs) in common sole (Solea solea L.) from main nursery zones along the French coasts

Brominated flame retardants (BFRs) were investigated in juvenile common sole from nursery zones situated along the French coast in 2007, 2008 and 2009. Extensive identification was performed with regard to PBDEs, novel BFRs 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenylethane (DBDPE), and other non-PBDE BFRs, namely, hexabromobenzene (HBB) and 2,2′,4,4′,5,5′-hexabromobiphenyl (BB-153). Polybrominated diphenyl ether (PBDE) concentrations (Σ 14 congeners) ranged from 0.01 ng/g to 0.16 ng/g wet weight (ww) in muscle, and 0.07 ng/g to 2.8 ng/g ww in liver. Concentrations were in the lower range of those reported in the literature in other European locations. Lower PBDE concentrations, condition indices and lipid contents were observed in the Seine estuary in 2009, possibly in relation to a lower water flow. The PBDE patterns and ratios we observed suggested that juvenile sole have a relative high metabolic degradation capacity. Non-PBDE BFRs were detected at lower levels than PBDEs, i.e., within the < method detection limit - 0.005 ng/g ww range in muscle, and < method detection limit - 0.2 ng/g ww range in liver. The data obtained is of particular interest for the future monitoring of these compounds in the environment.