Gene-Expression Programming for the Development of a Stage-Discharge Curve of the Pahang River

This study presents Gene-Expression Programming (GEP), an extension of Genetic Programming (GP), as an alternative approach to modeling the stage-discharge relationship for the Pahang River. The results are compared to those obtained by more conventional methods, i.e., the stage rating curve (SRC) and regression techniques. Additionally, the explicit formulations of the developed GEP models are presented. The performance of the GEP model was found to be substantially superior to both GP and the conventional models.     

Latex-coated polymeric monolithic ion-exchange stationary phases. 2. Micro-ion chromatography

Latex-coated monolithic polymeric stationary phases are used for micro-ion chromatography (mu-IC) of inorganic anions. Monolithic columns were prepared by the in situ polymerization of butyl methacrylate, ethylene dimethacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid within fused-silica capillaries of varying internal diameters. Introduction of ion-exchange sites was achieved by coating the anionic polymeric monolith with either Dionex AS10 or Dionex AS18 quaternary ammonium functionalized latex particles to give total ion-exchange capacities in the range 9-24 nequiv for a 30-cm column. The resultant mu-IC columns were used for the separation of anionic analytes using chloride or acetate as the eluent-competing ion and direct UV spectrophotometric detection at 195 nm or using hydroxide as the eluent-competing ion and suppressed or nonsuppressed contactless conductivity detection. Separation efficiencies of 13,000 plates/m were observed (for iodate), and separation efficiency was maintained for large increases in flow rate (up to 42 microL/min, corresponding to a linear flow velocity of 18.5 mm/s), enabling highly reproducible, rapid separations to be achieved (seven analyte anions in less than 2 min). Use of a hollow fiber micromembrane suppressor enabled effective suppression of hydroxide eluents over the range 0.5-5.0 mM, thereby permitting suppressed conductivity detection to be performed. However, the relatively large size of the suppressor resulted in reduced separation efficiencies (e.g., 5400 plates/m for iodate). Detection limits obtained with suppressed conductivity detection were in the range 0.4-1.2 microM.     

Removal of cadmium and manganese by a non-toxic strain of the freshwater cyanobacterium Gloeothece magna.

The ability of both living and dry cells of Gloeothece magna, a non-toxic freshwater cyanobacterium, to adsorb cadmium and manganese is demonstrated in this study. Chlorophyll a content of living cells was not influenced by either cadmium or manganese concentrations, indicating that adsorption of both Cd²⁺ and Mn²⁺ by living cells of G. magna, was independent of the metabolic state of the organism. Moreover, the adsorption of both Cd²⁺ and Mn²⁺ to living cells and dry cells, was dependent on the metal concentrations, and fitted the Freundlich adsorption isotherm. However, dry cells had larger binding capacity for both Cd²⁺ (K_f=912.6) and Mn²⁺ (K_f=2398) than living cells (K_f=151.4 & 63, respectively). The role of the capsular polysaccharides, the main constituents of the cyanobacterial envelope, in binding these two metals was also studied. Polysaccharide extracts of this organism adsorbed high amounts of both Cd²⁺ (115–425 μg mg⁻¹) and Mn²⁺ (473–906 μg mg⁻¹). This study suggests that G. magna would probably be cultured in water bodies contaminated by heavy metals to ameliorate their toxicity. Also dry material of this cyanobacterium being a non-toxic species, could be used as a safe biofilter to remove toxic metals from drinking water.     

Finite Element Analysis of Glass Fiber‐Reinforced Polyamide Engine Oil Pan Subjected to Localized Low Velocity Impact from Flying Projectiles

This paper investigates low velocity impact involving a glass fiber‐reinforced polyamide engine oil pan as part of a complete new development of thermoplastic components. The assessment of the impact resistance has driven the need to employ LS DYNA for finite element modeling in order to benchmark and predict the strength and fracture behavior of stressed plastic parts. In order to develop a reliable predictive capability and to validate simulations, complete components were manufactured by injection molding techniques for the experimental samples. Low velocity impact investigations were carried out using a gas gun and a falling weight tester in order to simulate impact events to which the oil pan is subjected whilst in operational service. This was intended to point out damage tolerance and failure mechanisms likely to occur in the structure. The study results show the significant contribution of the design in terms of shock absorption. Specific oil pan design with protective ribbing combined with a superior material considerably improves the impact resistance. The paper provides results and discussions on experimental and finite element analysis investigations before concluding with some remarks.     

Preparation of asymmetric polysulfone/polyimide blended membranes for CO<Subscript>2</Subscript> separation

Asymmetric Flat sheet polysulfone-polyimide (PSF-PI) blended polymeric membranes (with PI content from 5–20%) have been fabricated following phase inversion technique. The membranes have been thoroughly characterized by the measurement of porosity, mechanical properties and also by SEM, FTIR and DSC analyses. With the increase in the PI content, the mechanical properties of the membranes, like Young’s modulus, tensile strength and elongation at break, increased. SEM investigations revealed that the surfaces of fabricated blended membranes possessed adequate homogeneity and their cross-sections showed non-porous top and diminutive porous substructure. From DSC analyses it has been observed that different compositions of the blended membranes exhibited single glass transition temperatures, implying proper compatibility of the polymers. The permeance of CO₂ and CH₄ through the membrane increased with the increase in PI content and it gradually decreased with the increase in the feed pressure in the range of 2–10 bar. Under the present investigation, the membrane with 20% PI content exhibited the maximum selectivity for the separation of CO₂/CH₄ gas mixes.     

Formation of aluminium hydride (AlH3) via the decomposition of organoaluminium and hydrogen storage properties

Aluminium hydride (AlH₃) is a promising hydrogen storage material due to its competitive hydrogen storage density and moderate decomposition temperature. However, there is no convenient way to prepare/regenerate AlH₃ from (spent) Al by direct hydrogenation. Herein, we report on a novel approach to generate AlH₃ from the decomposition of triethylaluminium (Et₃Al) under mild hydrogen pressures (10 MPa) with the use of surfactants. With tetraoctylammonium bromide (TOAB), the synthesis led to the formation of nanosized AlH₃ with the known α phase, and these nanoparticles released hydrogen from 40 °C instead of the 125 °C observed with bulk α-AlH₃. However, when tetrabutylammonium bromide (TBAB) was used instead of TOAB, larger nanoparticles believed to be related to the formation of β-AlH₃ were obtained, and these decomposed through a single exothermic process. Despite the possibility to form α-AlH₃ under low conditions of temperature (180 °C) and pressure (10 MPa), TOAB stabilised AlH₃ was found to be irreversible when subjected to hydrogen cycling at 150 °C and 7 MPa hydrogen pressure.     

Simulation of Crude Palm Oil Dilution in a Palm Oil Mill Using Computational Fluid Dynamics

Computational fluid dynamics (CFD) simulation was applied to simulate the dilution of undiluted crude oil (UCO) in a dilution tank of a palm oil mill. Fluid flow and mixing characteristics were examined. Considering the mixing behavior, the mixing of dilution water and UCO occurred as soon as these fluids entered the dilution tank, and the oil mass fraction in the mixture decreased gradually towards the outlet of the tank. Meanwhile, the velocity of dilution water and UCO declined as the fluids moved from their respective inlets. The intensity of turbulence flow remained until near the tank outlet. For the parametric study, the oil mass fraction of diluted crude oil (DCO) increased with higher UCO flow rate and oil mass fraction in the UCO but declined with higher dilution water flow rate.     

Effect of Low Concentration Sn Doping on Optical Properties of CdS Films Grown by CBD Technique

Thin and transparent films of doped cadmium sulfide (CdS) were obtained on commercial glass substrates by Chemical Bath Deposition (CBD) technique. The films were doped with low concentration of Sn, and annealed in air at 300 °C for 45 min. The morphological characterization of the films with different amounts of dopant was made using SEM and EDAX analysis. Optical properties of the films were evaluated by measuring transmittance using the UV-vis spectrophotometer. A comparison of the results revealed that lower concentration of Sn doping improves transmittance of CdS films and makes them suitable for application as window layer of CdTe/CIGS solar cells.     

Physical properties of normal grade biodiesel and winter grade biodiesel

In this study, optical and thermal properties of normal grade and winter grade palm oil biodiesel were investigated. Surface Plasmon Resonance and Photopyroelectric technique were used to evaluate the samples. The dispersion curve and thermal diffusivity were obtained. Consequently, the variation of refractive index, as a function of wavelength in normal grade biodiesel is faster than winter grade palm oil biodiesel, and the thermal diffusivity of winter grade biodiesel is higher than the thermal diffusivity of normal grade biodiesel. This is attributed to the higher palmitic acid C(16:0) content in normal grade than in winter grade palm oil biodiesel.