International Journal of Engineering
Volume:22 Issue: 2, Aug 2009

Dairy wastewater is enriched in organic matter (about 45-72 g/l, COD) and also contains biodegradable carbohydrates. A three-stage system, NRBC was fabricated as a bench scale unit for lab experiments, to remove organic carbon from the whey. The fabricated NRBC had several advantages, such as quick start-up, high biomass concentration and was additionally able to handle high organic loading rates. In this study, the COD removal efficiencies of 80 and 83 percent were achieved at HRT of 16 and 24 h, respectively. While the HRT was increased to 36 h, the COD removal efficiency was increased to 92 percent. High surface COD loading rate of 38-210 g COD/m2.day was achieved. The high organic loading rate of whey was successfully treated in the fabricated NRBC. The COD removal efficiency of 96 percent was achieved, while the discs surface was increased by 10 percent.

Chemical recovery of methyl acetoacetate from the amoxicillin plant’s waste stream was investigated. In process of amoxicillin production for activation of amoxicillin molecule, hydrolysis takes place at final stage. As a result methyl acetoacetate is formed. Liquid-liquid extraction was employed for the recovery of methyl acetoacetate from the waste stream. Diluted alkaline solution was used as an extractive agent for the chemical extraction process. Extraction was carried out while the pH was adjusted to 9.5 by addition of alkaline solution. The extraction was repeated in three consecutive stages to enhance the process yield. Finally, distillation was carried out to remove the volatile compounds residues. Samples were taken from each stage of separation for GC analysis. The recovered methyl acetoacetate with purity of 93 % and yield of 75 % was obtained from extraction and distillation processes.

Chemical recovery of methyl acetoacetate from the amoxicillin plant’s waste stream was investigated. In process of amoxicillin production for activation of amoxicillin molecule, hydrolysis takes place at final stage. As a result methyl acetoacetate is formed. Liquid-liquid extraction was employed for the recovery of methyl acetoacetate from the waste stream. Diluted alkaline solution was used as an extractive agent for the chemical extraction process. Extraction was carried out while the pH was adjusted to 9.5 by addition of alkaline solution. The extraction was repeated in three consecutive stages to enhance the process yield. Finally, distillation was carried out to remove the volatile compounds residues. Samples were taken from each stage of separation for GC analysis. The recovered methyl acetoacetate with purity of 93 % and yield of 75 % was obtained from extraction and distillation processes.

The objective of this study is to investigate the effectiveness of externally bonded CFRP sheets to increase the flexural strength of reinforced high strength concrete (HSC) beams. Four-point bending flexural tests to complete failure on six concrete beams, strengthened with different layouts of CFRP sheets were conducted. Three-dimensional nonlinear finite element (FE) models were adopted by ANSYS to examine the behavior of the test beams. More specifically, the strength and ductility of the beams is investigated, as the number of FRP layers and tensile reinforcement bar ratio changed. With the exception of the control beam, one to four layers of CFRP were applied to the specimens. The ductility characteristics of the test beams were evaluated in terms of the displacement, curvature and energy ductility index. It was found that for all the reported beams, the energy ductility value is about two times higher than the displacement ductility values. The crack patterns in the beams are also presented. The load deflection plots obtained from numerical study show good agreement with the experimental results.

A theoretical relation is presented between the seismological Fourier amplitude spectrumand the mean squared value of the elastic response, which is defined by Gaussian distribution. Byshifting a general process to its mean value, spectrum of the mean squared value of the displacementis computed from the Fourier amplitude spectrum and the real part of the relative displacementtransfer function of the single-degree-of-freedom elastic oscillator. It is shown that the relationpresented in this work opens the door for a better understanding of the relationship between timeinvariantmean squared value of linear response of a single degree freedom system and seismologicalvariables, such as magnitude, focal distance, and path and soil conditions. For illustrating theproposed theoretical relation, the mean squared values of a drift have been calculated for earthquakeground motions with different magnitude, focal distance and soil.

Watt’s bath and pulse reverse (PR) electrodeposition is used to produce spherical nickelmultiwall carbon nanotubes (Ni-MWCNT) of 2.00, 0.93, 1.63 and 6.71 μm diameter and a variety ofsize distributions. For 60 cycles, an absolute electrodeposition current of 18 A/dm2 is applied atcurrent ratios of ii = idissolution/ideposition = 0, 0.077, 0.200 and 0.368. A simple exponential equation isfitted to each pulse response by a resistance-capacitance (RC) simple model giving different timeconstants usable for diagnosing the effect of different parameters. Results show that PRelectrodeposition is capable of producing microspherical Ni-MWCNT composite skeins of differentdiameters and size distributions. This could be identified with the time constant of the process.

Production of nanostructured aluminum matrix composite powder by high energy ball milling is investigated. Scanning electron microscopy analysis as well as the tap and green density measurements were used to optimize the milling time needed for the completion of the mechanical milling process. Also, we studied the particles morphology and size distribution change with milling time and its correlation with pressability and tap density. SEM showed that distribution of alumina particles in the Al matrix reaches a full homogeneity after the steady state. This would increase the hardness of powder due to a nano-structured matrix and oxide dispersion strengthening.

Zinc oxide thin films were deposited on soda-lime glass substrates from an aqueous zinccontaining complex by two-stage chemical deposition (TSCD) method. Longmuir adsorption model showed that the adsorption of atoms on the surface of the substrate was typically physical. The relation between the fractional coverage, θ, with the equilibrium constant of the adsorption reaction was nonlinear indicating that the adsorption was non-ideal. The percentage of porosity, 1-θ, of the thin layer was determined as a function of Zn2+ concentration of the solution. By application of XRD technique, it was shown that pure crystalline ZnO of controllable thickness could be deposited by TSCD method on the surface of the substrate. The procedure consisted of immersion into (a) cold Zn2+ complex containing solution and (b) hot water at 90, 95 and 98°C.

The characteristics of a cavitation water tunnel test setup and the experiments of cavitation around different models are given in this paper. Models of test are formed from combination of head and variable length afterbody. The experiments are performed initially with the smooth head and then with the roughened head. Cavitation initiates both in the wake and after the head. If the nose of models is roughened then cavitation initiates at the lower cavitation numbers. The cavitation inception is a function of the model geometry, nose condition and upstream flow characteristics. During the measuring process of drag force from non-cavitating flow regions to supercavitation case, only the tunnel pressure is reduced continuously. All measurements are performed at several Reynolds numbers. After cavitation inception in the wake, drag force increases continuously and fast. When cavitation initiates at the end of head, the mentioned force is maximum value and then decreases gradually. Supercavity is specified and compared with wedge case. The choking flow case is investigated around the models completely.

Core yarn was spun by introducing a PVA multifilament as the core through the yarn forming zone of a ring spinning frame and viscose fibers as the sheath containing tracer fibers. The water soluble PVA multifilament was extracted from the yarn structure. Then internal structure and properties of the hollow ring yarn was assessed and compared with those of typical ring yarns. Also, two plain fabric samples with hollow and typical weft ring yarns were produced to investigate the effect of hollowness and fibers collapse on the structural parameters of the fabrics. Bending behavior and air permeability of these fabrics were consequently studied. The results showed the mean value of fiber spinning-in-coefficient (Kf) and strength of hollow and typical ring yarns were very close, but elongation at break, unevenness and hairiness of hollow ring yarn is more than those of typical ring yarn. Results indicated that the bending rigidity and air permeability of the fabrics constructed from hollow ring weft yarn were improved due to the collapse of the fibers in the center of yarn and better flattening.

In this study, the effect of hygrothermal conditioning on the moisture diffusion properties of the fabric composite (glass fiber/epoxy resin) was investigated. The water uptake of the specimens conditioned in humid environment at different relative humidities (0, 60 and 96 % r.h) at constant temperature (60°C) was evaluated by weight gain measurements. The moisture diffusion properties of the fabric composite (glass fiber/epoxy resin) were determined using standard weight gain method. The weight gain experiments were performed to determine the equilibrium moisture content Mm of the fabric composite as a function of relative humidity (r.h). The measured weight gain is then fit to the solution to the diffusion equation (Fick’s law) to determine the diffusivity D. The comparison carried out between the values obtained of the characteristic parameters (D and Mm) of the kinetics of water absorption by the hygrothermal test of conditioning carried out into the laboratory and those given by Loos and Springer confirms the following principal remarks clearly: the diffusion coefficient D and the maximum weight gain Mm depend not only on the nature of material but also of the environmental conditions (hygrothermal conditioning). The maximum concentration of water (matrix+interface) obtained from calculations based on measured values, where a homogeneous diffusion phenomenon is assumed inside the material (Df=0), shows clearly that the presence of fibers in a polymeric matrix reduces the water up-take of the matrix by about 4 times.