Sweeping Gas Membrane Distillation (SGMD) as an Alternative for Integration of Bioethanol Processing: Study on a Commercial Membrane and Operating Parameters

This article considers the application of the sweeping gas membrane distillation process (SGMD) for direct separation of ethanol-water using a flat sheet PTFE membrane. It also studies the effect of operating parameters including feed concentration, feed temperature, feed flow rate, and sweeping gas flow rate on the permeation flux and selectivity of ethanol/water. The results showed that the increase in feed temperature increases in permeate flux and selectivity. Selectivities of 18.5 to 25 were achieved using dilute feeds within the temperature range of 35 to 55°C. However, by increasing the feed concentration by more than 5 wt.%, the selectivity was decreased. The increase in permeation flux and ethanol selectivity at higher feed flow rates was mainly due to the reduction of polarization effects. Moreover, the PTFE membrane was characterized by AFM. The results showed that the present process could be used as a stand-alone technique for bioethanol process integration.     

Prediction of Nusselt Number and Friction Factor of Water-Al2O3 Nanofluid Flow in Shell-and-Tube Heat Exchanger with Helical Baffles

Heat transfer and flow field of water-Al₂O₃ nanofluid were simulated three-dimensionally in the shell-side of shell-and-tube heat exchanger with helical baffles. The effects of Reynolds number and volume fraction on heat transfer and pressure drop were evaluated. Increasing the volume fraction and Reynolds number intensified both heat transfer and pressure drop. Reduction of the Reynolds number increased the friction factor, but no considerable change was observed in the friction factor by increasing the volume fraction at constant Reynolds number. Heat transfer of the nanofluid revealed greater dependency on the volume fraction of particles at lower Reynolds numbers. Models of Nusselt number and friction factor were obtained in the heat exchanger in terms of Reynolds number and volume fraction using neural network. The neural network predicted the output variables with great accuracy.     

Poly(vinylidene fluoride)–acrylic rubber partially miscible blends: Phase behavior and its effects on the mechanical properties

A phase diagram of poly(vinylidene fluoride) (PVDF) and acrylic rubber (ACM) was plotted, and the effects of the extent of miscibility on the mechanical properties of the polymer blends were examined. A compressible, regular solution model was used to forecast the phase diagram of this blend. The model prediction, the lower critical solution temperature (LCST) over the upper critical solution temperature (UCST), was done qualitatively according to the experimentally determined phase diagram by differential scanning calorimetry (DSC), optical microscopy, and rheological analysis. These experimental methods showed that this system was miscible in ACM‐rich blends (>50% ACM) and partially miscible in PVDF‐rich blends. A wide‐angle X‐ray diffraction study revealed that PVDF/ACM blends such as neat PVDF had a characteristic α‐crystalline peak. The partially miscible blends displayed up to 350% elongation at break; this was a significant increment of this parameter compared to that of neat PVDF(20%). However, the miscible blends showed elongation of up to 1000% [again, a remarkable increase compared to chemically crosslinked ACM (220%)] and displayed excellent mechanical properties and tensile strength and a large elongation at break. For the miscible and partially miscible blends, two different mechanisms were responsible for this improvement in the mechanical properties. It was suggested that in the partially miscible blends, the rubbery depletion layer between the spherulite and the conventional rubber cavitations mechanism were responsible for the increase in the elongation at break, whereas for the miscible blends, the PVDF spherulite acted as a crosslinking junction. The stretched part of the tensile samples in the partially miscible blends showed characteristic β‐crystalline peaks in the Fourier transform infrared spectra, whereas that in the miscible blends showed α‐crystalline peaks. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1247‐1258, 2013     

SEQUENCE STRATIGRAPHIC ANALYSIS OF THE MID‐CRETACEOUS MISHRIF FORMATION,SOUTHERN MESOPOTAMIAN BASIN,IRAQ

The middle Cenomanian – early Turonian Mishrif Formation, a major carbonate reservoir unit in southern Iraq, was studied using cuttings and core samples and wireline logs (gamma‐ray, density and sonic) from 66 wells at 15 oilfields. Depositional facies ranging from deep marine to tidal flat were recorded. Microfacies interpretations together with wireline log interpretations show that the formation is composed of transgressive and regressive hemicycles. The regressive hemicycles are interpreted to indicate the progradation of rudist lithosomes (highstand systems tract deposits) towards distal basinal locations such as the Kumait, Luhais and Abu Amood oilfield areas. Transgressive hemicycles (transgressive systems tract deposits) represent flooding of the shallow carbonate platform and are recorded in oilfields such as Amara, Halfaya and Zubair. A sequence stratigraphic framework has been constructed for the Mishrif Formation based on correlation of the transgressive and regressive hemicycles which are separated by maximum flooding surfaces. Three third‐order sequences are identified which show lateral and vertical facies variations depending on relative sea‐level changes. Sequence boundaries are characterized by karstic, exposure and drowning features. Middle Cenomanian – Turonian eustatic sea‐level changes together with regional‐scale tectonic deformation of the Arabian Plate controlled the availability of accommodation space and therefore the depositional profile during development of each sequence. Both of these factors controlled the maximum flooding surfaces and sequence boundaries which have been identified. The sequence stratigraphic key surfaces presented in this study represent typical candidate horizons or datum surfaces for future seismic or resevoir modelling studies. Also, lateral facies variations in each transgressive‐regressive sequence and associated carbonate bodies (i.e. prograding shelf margin, forced regressive wedge) may form important stratigraphic traps in the Mesopotamian Basin.     

Detection of Adulteration in Saffron Samples Using Electronic Nose

Saffron is the commercial name of the dried stigmas of Crocus sativus L. flower. Due to the high cost of saffron, adulteration sometimes occurs in the local market. In this study, the aroma fingerprints of saffron, saffron with yellow styles, safflower, and dyed corn stigma were detected by an electronic nose system. The features of the obtained signals from electronic nose system were extracted and used for data analysis. In this work, principal component analysis was used and the results were confirmed by back propagation artificial neural networks. The results revealed that the system can recognize the saffron adulteration satisfactorily. As a conclusion, it was found that the electronic nose could provide good separation of the saffron and adulterated one (safflower and other adulteration) as 100 and 86.87% classification accuracy, respectively, by means of artificial neural networks. The electronic nose was able to differentiate non-adulterated and adulterated saffron at higher than 10% adulteration level successfully.     

Mechanical,Physical, Antioxidant,and Antimicrobial Properties of Gelatin Films Incorporated with Thymol for Potential Use as Nano Wound Dressing

The aim of this study was to determine the properties of gelatin films incorporated with thymol. Gelatin films were prepared from gelatin solutions (10% w/v) containing thymol (1, 2, 4, and 8% w/w), glycerol (25% w/w) as plasticizer, and glutaraldehyde (2% w/w) as cross‐linker. Cross‐likened films showed higher tensile strength, higher elongation at break, lower Young's modulus, lower water solubility, lower swelling, lower water uptake, and lower water vapor permeability. Incorporation of thymol caused a significant decrease in tensile strength, increase in elongation at break, decrease in Young's modulus, increase in water solubility, decrease in swelling and water uptake, and increase in water vapor permeability slightly. The films incorporated with thymol exhibited excellent antioxidant and antibacterial properties. The antibacterial activity of the films containing thymol was greatest against Staphylucoccus aureus followed by Bacillus subtilis followed by Escherichia coli and then by Pseudomonas aeruginosa. Thus, gelatin films‐containing thymol can be used as safe and effective source of natural antioxidant and antimicrobial agents with the purpose of evaluating their potential use as modern nano wound dressing. Practical Application : This study clearly demonstrates the potential of gelatin films incorporated with thymol as natural antioxidant and antimicrobial nano film. Such antimicrobial films exhibited excellent mechanical, physical, and water activities and could be used as antibacterial nano wound dressing against wounds burn pathogens.     

Synthesis of mesoporous nanocrystalline zirconia with tetragonal crystallite phase by using ethylene diamine as precipitation agent

Mesoporous nanocrystalline zirconia with high surface area and pure tetragonal crystallite phase has been prepared by bifunctional ethylene diamine as both precipitating agent for ZrO(NO₃)₂ to ZrO(OH)₂ and colloidal protecting agent for the ZrO(OH)₂ nanoparticles. The effect of refluxing time and temperature on the structural properties of the zirconia were investigated. The obtained results showed that the increasing in refluxing time and temperature improved the thermal stability and increased the tetragonal content of the zirconia. The results also showed that the addition of Pluronic P123 block copolymer surfactant acted as a cosurfactant and increased the specific surface area of the zirconia.     

A Worst-Case Robust Combination Method of Beam-Forming and Orthogonal Space–Time Block Coding

In this paper, a new robust multi-input multi-output system is proposed in a perturbed wireless channel which is to model imperfect channel information at the source side when beam-forming and orthogonal space–time block coding is utilized. The channel perturbation is bounded by a predefined variation based on worst-case robust design. Beam-forming is used to improve the performance of the system expressed by the upper bound of pairwise error probability of symbols. In this paper firstly, the maximum value of pairwise error probability is obtained in a closed form when channel perturbation is kept below a threshold. Then the beam-forming matrix is designed to minimize the pairwise error probability subject to a predefined maximum transmitting power. This approach provides near optimal results due to using the upper bound of pairwise error probability. It shows good performance based on the symbol error rate criterion compared with other existing methods of the multiple input multiple output system.     

A wideband receiver front-end using 1st and 3rd harmonics of the <Emphasis Type="Italic">N</Emphasis>-path filter response

Harmonic selectivity and inaccessibility to accurate low-power high frequency clock generator are two main imperfections in the tunable N-path filters. In this paper, conventional N-path filter and conventional harmonic rejection (HR) N-path architectures are analyzed, and related equations are derived and are verified by simulation results. Furthermore, a wideband tunable receiver front-end using HR N-path switching systems is proposed. Using third harmonic of filter response instead of fundamental harmonic, the required input clock frequency in the multi-phase clock generator is decreased by a factor of three. The receiver front-end benefits low and high frequency bands. At low frequency band (0.4–1.2 GHz) the first harmonic, and at high frequency band (1.2–3.3 GHz) the third harmonic of filter response are selected and are downconverted to the baseband frequency. The structure is designed and is simulated using CMOS-90 nm technology in schematic level. The total power consumption and \(S_{11}\) are \(<27.14\) mW and \(-13.5\) dB, respectively. Furthermore, NF at low and high frequency bands are 2.56 and 3.53 dB, respectively.