Interaction of whey protein with polyphenols from salal fruits (Gaultheria shallon) and the effects on protein structure and hydrolysis pattern by Flavourzyme®

Milk whey can interact with polyphenols leading to the formation of complexes. In this research, whey protein was fortified with salal fruits (SB) extract and the effect on protein structure was investigated. Particle size and tertiary structure analysis indicates α-lactalbumin–ligand interactions when whey is supplemented with SB extract. Circular dichroism spectroscopy suggests conformational changes of α-Lac to a partially unfolded state as indicated by the decrease in α-helix structures. Enzymatic treatment of whey protein mixed with SB revealed differences in the hydrolysis pattern. LC-MS/MS data analysis indicates that a higher number of peptides are released when whey is mixed with SB. Peptides of known bioactivity were identified in all hydrolysates. The supplementation of whey protein with SB extract can influence protein hydrolysis and the release of peptides following enzymatic treatment with commercial proteases which may affect the functional and health-related properties of the hydrolysate.     

Performance of Pilot-scale Constructed Floating Wetlands in the Removal of Nutrients and Pesticides

Aiming to evaluate the efficacy of constructed floating wetlands (CFW) in removing agrochemicals (nutrients and pesticides), a series of experiments were run continuously for a 16-week period in pilot-scale CFW systems to study the effect of two aquatic plant species (duckweed and water hyacinth) and climatic parameters. The CFW systems were loaded daily with agricultural polluted water containing a fertilizer and five pesticides, whose concentrations and removal efficiencies were measured in the experiments. Average nutrient and pesticide reductions varied from 27.4% to 83.6% and from 12.4% to 42.7%, respectively. The two plants performed almost equally well. High temperatures and increased solar radiation significantly contributed to increased removal performance. The results suggest the use of CFW systems as effective and low-cost agricultural pollution control technologies.

     

Branch length distribution in TREF fractionated polyethylene

Commercial polyethylene is typically heterogeneous in molecular weight as well as in molecular topology due to variability in catalyst systems and catalyst activity. Further, processing of polyethylene after polymerization may also result in changes to the structure. While quantification of molecular weight is routine using gel permeation chromatography (GPC); quantification of the heterogeneity in molecular topology and microstructure is more difficult. In this paper, a novel method is used to examine the structure and branch content of a linear low-density polyethylene (LLDPE). The method uses a scaling model to analyze small-angle neutron scattering (SANS) data from dilute solutions of a series of LLDPE fractions. The scaling approach quantifies short-chain and long-chain branch content in polymers concurrently, thereby illustrating the distribution of these branches in the polyethylene fractions. Additionally, new quantities such as the average long-chain branch length and hyperbranch content are measured to provide further insight into the structure of these polymers. LLDPE used in this study is fractionated using temperature rising elution fractionation (TREF). Results from the analysis of these fractions show evidence of long-chain branching in commercial LLDPE which could be partly attributed to post-synthesis processing conditions.     

Foldings and grazings of tori in current controlled interleaved boost converters

Interleaved boost converters (IBCs) are used when energy conversion is required at high current levels. Such converter systems may undergo various nonlinear phenomena which can affect their performance adversely. In this paper, we study an IBC and demonstrate the first instability through a Neimark–Sacker bifurcation, resulting in a torus. An analysis based on the calculation of the monodromy matrix reveals that the torus has a rather strange form as the complex Floquet multipliers that became unstable have a real value close to ?1. We show that further variation in a parameter can result in novel nonlinear phenomena where the torus itself folds and grazes a switching manifold, resulting in a ‘wobbling’ of the closed loop that represents the torus in discrete time. Numerical and analytical results validate our work. Copyright © 2013 John Wiley & Sons, Ltd.     

Microbiological,chemical and sensory changes of whole and filleted Mediterranean aquacultured sea bass (Dicentrarchus labrax) stored in ice

The effect of filleting on the microbiological, chemical and sensory properties of aquacultured sea bass (Dicentrarchus labrax) stored in ice was studied. Pseudomonads, H₂S‐producing bacteria (including Shewanella putrefaciens) and Brochothrix thermosphacta were the dominant bacteria at the end of the 16 day storage period in ice for both whole ungutted and filleted sea bass. Enterobacteriaceae were also found in the spoilage microflora of whole ungutted and filleted sea bass, but their counts were always lower than those of pseudomonads, H₂S‐producing bacteria (including S putrefaciens) and B thermosphacta. Total viable counts for whole ungutted sea bass were always lower than those for filleted sea bass samples. Of the chemical indicators of spoilage, TMA (trimethylamine) values of whole ungutted sea bass increased very slowly, whereas significantly higher values were obtained for filleted samples, with respective values of 0.253 and 1.515 mg N per 100 g muscle being reached at the end of their shelf‐life (days 13 and 9 respectively). TVB‐N (total volatile basic nitrogen) values showed a slight increase for whole ungutted sea bass during storage, reaching a value of 26.77 mg N per 100 g muscle (day 13), whereas for filleted fish a corresponding value of 26.88 mg N per 100 g muscle was recorded (day 9). TBA (thiobarbituric acid) values increased slowly for whole ungutted and filleted sea bass samples throughout the entire storage period, reaching final values of 4.48 (day 13) and 13.84 (day 9) mg malonaldehyde kg^?1 respectively. Sensory assessment of raw fish using the EC freshness scale gave a grade E for up to 5 days for whole ungutted sea bass, a grade A for a further 4 days and a grade B for an additional 4 days, after which sea bass was graded as C (unfit). Overall acceptability scores for odour, taste and texture of cooked whole ungutted and filleted sea bass decreased with increasing time of storage. The results of this study indicate that the shelf‐life of sea bass stored in ice, as determined by overall acceptability sensory scores and microbiological data, is 8–9 days for filleted and 12–13 days for whole ungutted fish. Copyright © 2003 Society of Chemical Industry     

An Automated Ultrasonic NDT System for In-Situ Inspection of Wind Turbine Blades

It is crucial to maintain wind turbine blades regularly, due to the high stress leading to defects or damage. Conventional methods require shipping the blades to a workshop for off-site inspection, which is extremely time-consuming and very costly. This work investigates the use of pulse-echo ultrasound to detect internal damages in wind turbine blades without the necessity to ship the blades off-site. A prototype 2D ultrasonic NDT （non-destructive testing） system has been developed and optimised for in-situ wind turbine blade inspection. The system is designed to be light weight so it can be easily carried by an inspector onto the wind turbine blade for in-situ inspection. It can be operated in 1D A-scan, 2D C-scan or 3D volume scan. A software system has been developed to control the automated scanning and show the damage areas in a 2D/3D map with different colours so that the inspector can easily identify the defective areas. Experiments on GFRP （glass fibre reinforced plastics） and wind turbine blades （made of GFRP） samples showed that internal defects can be detected. The main advantages of this system are fully automated 2D spatial scanning and the ability to alert the user to the damage of the inspected sample. It is intended to be used for in-situ inspection to save maintenance time and hence considered to be economically beneficial for the wind energy industry.     

The Effect of Thermal Reduction on the Water Vapor Permeation in Graphene Oxide Membranes

In the present study, the influence of the thermal reduction on the water vapor transmission properties of thin graphene oxide (GO) membranes is evaluated. The macroscopically measured property of the Water Vapor Transmission Rate (WVTR) exhibits step like dependence contrary to the gradual microscopic structural alterations identified by several techniques (XPS, FTIR and XRD) applied in situ during the thermal annealing process. Three distinct regions of WVTR‐values associated with distinct interlayer distances i.e., >7.5 Å, ∼6 Å and <6 Å are essentially observed which may be compared to the findings of the recently reported first principle calculations. Our experimental results enable the understanding of the water vapor unimpeded transmission through the layers of the oxygen rich GO nanostructured membranes and consequently facilitate the design of functional membranes for separation applications.     

Model-driven eGovernment interoperability: A review of the state of the art

This paper reviews the state of the art in the area of enhancing eGovernment interoperability by using common models and/or ontologies. This area has currently become a very active research field. We identify and present a significant number (> 40) of relevant efforts. These initiatives are grouped into categories based on the owner, scope and modelling perspective of each project. We then focus on the cases that build generic and universal eGovernment representations and models. We analyse, evaluate and rate them using an additional set of criteria. We end up with conclusions and possible directions for the exploitation and usage of these models.     

Thermal and catalytic cracking of n-Heptane in presence of CaO,MgO and Calcined Dolomites

Experimental kinetic data on n-heptane pyrolytic and catalytic steam cracking, and product distribution data were obtained at reaction temperatures from 700° to 800°C at atmospheric pressure. The overall thermal cracking of n-heptane was compared to the cracking in presence of the basic catalysts MgO, CaO (low surface quicklime), and calcined dolomites.     

Robot arm-wrist coordination. Part 2. Design guidelines

In the companion article (Part 1), we developed a mathematical framework that provides for the analysis and quantitative rating of arm-wrist coordination. The objective of this article is to exploit this framework and formulate manipulator design guidelines for effective arm-wrist coordination and task execution. We explore various arm and wrist designs and quantify their performance in terms of meeting the two design objectives of efficient arm-wrist coordination and robot flexibility. Numerical simulation experiments highlight the measurable effects of both the fixed manipulator geometry and changing robot configuration on arm-wrist coordination and demonstrate the impact of the design guidelines on robot performance.