Demand function estimate for residential water in Oman

Current subsidies to residential water users in Oman are estimated at USD 314 million/y. This study estimates the demand function for residential water in Muscat, Oman, for households living in villas. A two-stage least squares econometric model with lagged average water price was used with socio-economic variables. Price elasticity for residential water in Muscat was estimated as –2.10. This high price elasticity is explained by the large proportion of water used for outdoor purposes. This study indicates that it may be possible to manage water demand in Muscat through modifying the price of water and reforming subsidies for residential water.     

Assessment of future climate change impacts on hydrological behavior of Richmond River Catchment

This study evaluated the impacts of future climate change on the hydrological response of the Richmond River Catchment in New South Wales (NSW), Australia, using the conceptual rainfall-runoff modeling approach (the Hydrologiska Byrans Vattenbalansavdelning (HBV) model). Daily observations of rainfall, temperature, and streamflow and long-term monthly mean potential evapotranspiration from the meteorological and hydrological stations within the catchment for the period of 1972–2014 were used to run, calibrate, and validate the HBV model prior to the streamflow prediction. Future climate signals of rainfall and temperature were extracted from a multi-model ensemble of seven global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 3 (CMIP3) with three regional climate scenarios, A2, A1B, and B1. The calibrated HBV model was then forced with the ensemble mean of the downscaled daily rainfall and temperature to simulate daily future runoff at the catchment outlet for the early part (2016–2043), middle part (2044–2071), and late part (2072–2099) of the 21st century. All scenarios during the future periods present decreasing tendencies in the annual mean streamflow ranging between 1% and 24.3% as compared with the observed period. For the maximum and minimum flows, all scenarios during the early, middle, and late parts of the century revealed significant declining tendencies in the annual mean maximum and minimum streamflows, ranging between 30% and 44.4% relative to the observed period. These findings can assist the water managers and the community of the Richmond River Catchment in managing the usage of future water resources in a more sustainable way.     

A Generalized Formula for Estimating Pure Alkenes Viscosity

Abstract

The importance of liquid viscosity in chemical process design makes it one of the most measured transport properties. Nevertheless, in the pure-component database, no experimental data on liquid viscosity for nearly 50% of the compounds are available. Therefore, prediction methods for liquid viscosity of alkenes over a wide range of absolute temperature for each components are necessary. Moreover, experimental data measured at lower temperatures are often extrapolated to higher temperatures with erroneous results. To improve liquid viscosity prediction of experimental data to temperatures and carbon numbers, we propose an empirical rule for estimating the viscosity of alkenes compounds. A predictive method, based physical properties (absolute temperature and carbon numbers) as its inputs, to correlate liquid viscosity by the statistical analysis is proposed. For a group of 19 compounds, the mean average absolute deviation was 4.6% for 118 data points. These values are better than other predictive methods and show that the statistical analysis model is stable and can be used to obtain good predictions for compounds that were not used in the model calibration.     

Estimation of Heat Capacity for Liquids

Abstract

Heat capacity of liquid in different temperatures are necessary in most engineering calculations. A general formula has been developed to calculate heat value of nonpolar or slightly polar compounds based on critical properties and molecular weight. This formula is a function of reduced temperature, critical temperature, critical pressure, molecular weight, and acentric factor. It is applied within a wide range of temperatures.     

New Statistical Concepts for Prediction Viscosity,Critical Temperature,and Critical Pressure of Homologous Hydrocarbon Series (C n H2n+2)

Abstract

A new model for prediction viscosity, critical temperature, and critical pressure for homologous hydrocarbon series C _n H_2n+2 as a function of carbon number only. The new model has a general formula: η or T _c or P = A ₁ C ^{A ₂} (2+2C) ^{A ₃} . This new model provides accurate and computationally reliable prediction for the corresponding properties (η, T _c , and P _c ) value.     

Slip MHD liquid flow and heat transfer over non-linear permeable stretching surface with chemical reaction

In the present study the magnetohydrodynamic (MHD) liquid flow and heat transfer over non-linear permeable stretching surface has been presented in the presence of chemical reactions and partial slip. By means of proper similarity variables, the fundamental equations of the boundary layer are transformed to ordinary differential equations which for the fixed values of the x-coordinate along the plate local similarity solution would be valid appropriately. The ordinary differential equations are solved numerically using an explicit Runge–Kutta (4, 5) formula, the Dormand–Prince pair and shooting method. As a result, the velocity profiles, the concentration profiles, temperature profiles, the wall shear stress, the local Sherwood number and the local Nusselt number for the various values of the involved parameters of the problem are presented and discussed in details.     

Estimation of the Equilibrium Constants for Pure Hydrocarbons

Equilibrium constants of pure hydrocarbons in different temperatures and pressures are necessary in most engineering calculations. A general formula has been developed to calculate equilibrium value for a group of hydrocarbons which have the general formula C_n H_2n+2 and C_n H_2n based on three parameters. This formula is a function of reduced temperature, reduced pressure, and an acentric factor. It is applied within a wide range of temperatures and pressures. As a result this technique is considered to be useful for the predication of K values of pure hydrocarbons depending on its reduced temperature, reduced pressure, and acentric factor.     

Diffusion Coefficient of a Binary Liquid System

A generalized diffusion coefficient correlation for a binary system of liquids has been developed to represent the data for a wide range of temperatures. Detailed analysis shows that the proposed correlation fits the experimental measurements of diffusivity with the corresponding calculated values with an acceptable percentage error.     

Dye-tolerant marine Acinetobacter baumannii-mediated biodegradation of reactive red

The objective of this study was to isolate a potent dye-degrading microbe that can be used to reduce the pollution caused by industrial dyes.Reactive red 198 is an extensively used textile dye and is a major environmental pollutant in water bodies. In this study, a bacterial strain was isolated from sea sediments and identified as Acinetobacter baumannii with 16S rRNA sequencing. The isolated bacteria were immobilized in calcium alginate and decolorization studies were carried out to determine the optimum pH, temperature, dye concentration, inoculum volume,and static/agitated condition using the one factor at a time(OFAT) approach. The Box-Behnken design, a type of response surface methodology,was adopted to improve the degradation efficiency. At 37℃ using an inoculum volume of six beads, 96.20% decolorization was observed in 500 mg/L of reactive red 198 after 72 h. Dye degradation was confirmed with UV-visible spectroscopy and Fourier-transform infrared(FTIR)spectroscopy studies of the dye and degraded metabolites. Microbial toxicity studies using Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa and phytotoxicity studies using Vigna radiata proved that the toxicity of the dye was significantly reduced after degradation. We can conclude that the isolated A. baumannii strain is an efficient dye-degrading microbe that can be used to reduce the pollution caused by industrial dyes.     

Single Phase Flow Pressure Drop in Glass Ballotini Particulate Beds

A study was made of pressure drop during single fluid phase flow to determine the pressure drop characteristic of the porous media (glass ballotini particulate beds) for coalescence. It is also served to check the reproducibility of the packing technique, and to detect any foreign particulate matter or re-arrangement of the individual particles in the coalesce bed. Furthermore these data provided a basis for comparison with that during two-phase flow with coalescence. For spherical particle the modified Carman-Kozeny equation was applied; the commonly accepted value for Kozeny constant is 5.0. However, K, depends on, among other factors, the structure of the bed, voidage fraction, particle shape, tortuosity, superficial velocity, bed depth, particle size, and wall effect.