Effect of Spray Nozzle Design on Fish Oil–Whey Protein Microcapsule Properties

Abstract: Microencapsulation improves oxidative stability and shelf life of fish oil. Spray and freeze drying are widely used to produce microcapsules. Newer spray-nozzles utilize multiple fluid channels allowing for mixing of wall and core materials at the point of atomization. Sonic energy has also been employed as a means of atomization. The objective of this study was to examine the effect of nozzle type and design on fish oil encapsulation efficiency and microcapsule properties. A total of 3 nozzle types, a pressure nozzle with 1 liquid channel, a pressure nozzle with 2 liquid channels, and a sonic atomizer with 2 liquid channels were examined for their suitability to encapsulate fish oil in whey protein isolate. Physical and chemical properties of freeze dried microcapsules were compared to those of microcapsules produced by spray drying. The 2-fluid pressure and ultrasonic nozzles had the highest (91.6%) and the lowest microencapsulation efficiencies (76%), respectively. There was no significant difference in bulk density of microcapsules produced by ultrasonic and 3-fluid pressure nozzles. The ultrasonic nozzle showed a significantly narrower particle size distribution than the other nozzles. This study demonstrated that new nozzle designs that eliminate emulsion preparation prior to spray drying can be beneficial for microencapsulation applications. However, there is still a need for research to improve microencapsulation efficiency of multiple channel spray nozzles. Practical Application: Since this research evaluates new spray nozzle designs for oil microencapsulation, the information presented in this article could be an interest to fish oil producers and food industry.     

Optimal positioning of wind turbines on Gökçeada using multi‐objective genetic algorithm

This paper addresses the problem of optimal placement of wind turbines in a farm on Gokçeada Island located at the north‐east of Aegean Sea bearing full potential of wind energy generation. A multi‐objective genetic algorithm approach is employed to obtain optimal placement of wind turbines by maximizing the power production capacity while constraining the budget of installed turbines. Considering the speed and direction history, wind with constant intensity from a single direction is used during optimization. This study is based on wake deficit model mainly because of its simplicity, accuracy and fast calculation time. The individuals of the Pareto optimal solution set are evaluated with respect to various criteria, and the best configurations are presented. In addition to best placement layouts, results include objective function values, total power output, cost and number of turbines for each configuration. Copyright © 2009 John Wiley & Sons, Ltd.     

Assessment of emissions at busy airports

Emissions are determined in the vicinity of airports and used to demonstrate that aircraft movements in the airport, as measured by landings and takeoffs, are not sufficient to evaluate the cumulative emission formation for an airport. In the investigation, eight busy airports are selected and three databases considered to obtain values of significant emissions, that is, hydrocarbons (HCs), CO, NO_x, CO₂ and H₂O. Findings for airports are compared. The results indicate that, despite the fact that aircraft movements for the Atlanta airport are the highest of those considered and almost double those for the London airport, the latter has greater emissions of HCs and NO_x. Although the Atlanta airport exhibits greater emissions of CO and CO₂ than the London airport, the difference is minor but opposite to the expected values based on numbers of landings and takeoffs. Copyright © 2009 John Wiley & Sons, Ltd.     

Exfoliation targeted toughness enhancement in polypropylene‐blend‐ montmorillonite nanocomposites

BACKGROUND: Both exfoliated and toughened polypropylene‐blend‐montmorillonite (PP/MMT) nanocomposites were prepared by melt extrusion in a twin‐screw extruder. Special attention was paid to the enhancement of clay exfoliation and toughness properties of PP by the introduction of a rubber in the form of compatibilizer toughener: ethylene propylene diene‐based rubber grafted with maleic anhydride (EPDM‐g‐MA). RESULTS: The resultant nanocomposites were characterized using X‐ray diffraction, atomic force microscopy, scanning electron microscopy, thermogravimetric analysis, dynamic mechanical analysis and Izod impact testing methods. It was found that the desired exfoliated nanocomposite structure could be achieved for all compatibilizer to organoclay ratios as well as clay loadings. Moreover, a mechanism involving a decreased size of rubber domains surrounded with nanolayers as well as exfoliation of the nanolayers in the PP matrix was found to be responsible for a dramatic increase in impact resistance of the nanocomposites. CONCLUSION: Improved thermal and dynamic mechanical properties of the resultant nanocomposites promise to open the way for highly toughened super PPs via nanocomposite assemblies even with very low degrees of loading. Copyright © 2008 Society of Chemical Industry     

The Influence of Inoculum Level on Fermentation and Flavour Compounds of White Wines Made from cv. Emir

In this study, the influence of the addition of a commercial wine yeast (Saccharomyces cerevisiae) at inocula of 1 × 10⁴ to 1 × 10⁷ cells/ml in Emir must was investigated with a focus on yeast growth, fermentation rate, ethyl alcohol and flavour compound formation. Spontaneous fermentation without inoculation was also performed. Higher peak counts were observed with higher amounts of S. cerevisiae yeast. Addition of various amounts of yeast led to the earlier disappearance of non‐Saccharomyces yeasts. The fermentation rate was improved with higher amounts of yeast, but ethanol production was not affected. Concentrations of higher alcohols increased with increasing inoculum levels, especially inoculum sizes of 1 × 10⁶ cells/ml and 1 × 10⁷ cells/ml. The amount of ethyl acetate was reduced with increased inoculum levels.     

Policosanol contents of beeswax,sugar cane and wheat extracts

Policosanol (PC) is a mixture of high molecular weight aliphatic primary alcohols. Currently, a number of dietary supplements containing PC are commercially available in the US market. The majority of these products are prepared from beeswax or sugar cane extracts. The main objective of this study was to compare the PC contents and compositions of beeswax, sugar cane and wheat as PC sources. The PC contents and compositions of several commercial dietary supplements were also analyzed. The precipitate formed during the cold storage of commercially hexane-extracted wheat germ oil (WGO) contained the highest total PC (628 mg/kg) among the wheat extracts and milling products examined in this study. The total PC contents of wheat straw (164 mg/kg) and sugar cane peel (270 mg/kg) were of the same order of magnitude. The total PC contents of brown beeswax were about 20 and 45 times higher than those of the WGO-solids and sugar cane peel, respectively. Commercial dietary supplements contained less total PC than were claimed on the product labels. The PC compositions of the samples analyzed in this study varied significantly with the source. Wheat can be a viable PC source for further product development or health benefits.     

The challenges involved in concrete works of Marmaray immersed tunnel with service life beyond 100 years

Marmaray immersed tube crossing, located at the entrance of Bosphorus Strait of Istanbul, will be one of the unique infrastructure facility bringing great engineering challenges in immersed tunnel technology. The employer requires a minimum design life of 100 years for the immersed tunnel structure that will be under exposure of the highest saline water pressure at the depth of 58 m that has never been experienced yet in the history of immersed tube systems. Since the structural concrete is to be subjected to extremely aggressive environmental conditions during expected long-term service life, the quality assurance of the immersed tunnel has been ensured by setting a series of effective technical requirements taking into account the potential durability risks and predictive models in design phase, outputs of pre-testing activities and potential difficulties at construction period. The objective of this paper is to present some major steps involved in concrete works of this megaproject by giving the highlights from laboratory scale researches to the execution of the work at construction site.     

Synthesis of effective poly(4‐vinylpyridine) nanocomposites: in situ polymerization from edges/surfaces and interlayer galleries of clay

Poly(4‐vinylpyridine) (P4VP) nanocomposites have been prepared by using an in situ polymerization method in the presence of organically modified montmorillonite (MMT) clays with a quarternary salt of cocoamine containing a vinyl group, as well as trimethoxy vinyl silane. The nanocomposites were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The desired exfoliated nanocomposite structure was achieved when the MMT modification was conducted in the presence of both modifiers, whereas individual modifications all resulted in intercalated structures. This resultant exfoliated nanocomposite was found to have better thermal stability and dynamic mechanical performance when compared to the other nanocomposites, even with 2 % clay loading. Copyright © 2005 Society of Chemical Industry     

Time-parallel simulation of wireless ad hoc networks with compressed history

Time-parallel simulation (TPS) is a technique which partitions the timespan of the simulation into independently executed simulation segments. Unless the simulated process is regenerative, the output of TPS is only an approximation of the corresponding serial simulation. Previously we have adapted TPS to the simulation of wireless ad hoc networks. By prefixing the measured simulation segment with a warmup interval which can be dynamically extended, we were able to achieve arbitrary accuracy. In general, higher accuracy requires a longer warmup interval, which decreases the speedup.     

Effect of Processing Parameters on Flocculation of Picochlorum oklahomensis

The flocculation process is commonly used to separate suspended solids from water. The microalgae strain, Picochlorum oklahomensis (PO), was investigated for its flocculation characteristics. Efficiencies of biopolymer addition, pH adjustment and electroflocculation for biomass recovery from the culture medium were examined. Flocculation efficiency of PO increased sharply above pH 11 and reached 97 % at pH 13. Chitosan was more effective in flocculating PO cells than sodium alginate and cationic starch. A generalized linear mixed model using a beta distribution for response was utilized for optimization of the chitosan flocculation process variables. Biomass: chitosan ratio, pH and settling time (ST) were the independent variables. There were significant 3-way interactions among the variables. The highest PO flocculation efficiency, 98.4 %, was obtained at biomass: chitosan ratio of 2.78, pH 9 and ST of 12 h. The electroflocculation efficiency improved with increasing current, operation time (OT) and ST. The highest electroflocculation efficiency, 99.74 %, was obtained under the following conditions; 0.8 A (ampere) and 15 min and 12 h, OT and ST, respectively. This study demonstrated that pH adjustment, chitosan addition and electroflocculation were all technically viable methods to flocculate PO cells. However, selection of the most suitable technique and the optimum treatment conditions needs to be based not only on the application of algal biomass, but also on an economic feasibility study.