Extraction and fractionation of wheat flour proteins

With the aid of a 1.5% sodium dodecyl sulphate solution (SDS) the proteins of two Dutch wheat flours were separated into an SDS-soluble and an SDS-insoluble fraction. The SDS-soluble fraction was fractionated with the aid of ethanol precipitation and gel filtration chromatography into albumins, globulins, gliadins, glutenins II and III, and glutelins I, II, III and IV. The SDS-insoluble proteinaceous material was separated into glutenins I and glycoproteins. The protein fractions were identified with the aid of SDS-polyacrylamide gel electrophoresis and amino acid analysis. The glutenins I and II consist of A, B and C subunits. Their molecular weights ranged from about 600 000 to 10 million. The glutenins III consist only of B and C subunits and their molecular weights ranged from 300 000 to 600 000. A hypothesis explains how the glutenins III are the precursors for glutenins I and II and how they contribute to gluten's structure. The glutelins I consist of α β and γ subunits and their molecular weights ranged from about 600 000 to several millions. The glutelins II consist also of α β and γ subunits with a molecular weight of about 300 000 to 600 000, while the molecular weights of the glutelins III and IV ranged from 10 000 to 200 000. All glutelins are insoluble in 70 % aqueous ethanol and 5 M urea, but soluble in SDS and 0.1M NaOH. Only the glutelins III and IV are soluble in 0.1M HAc. The globulins consist of a heterogeneous fraction of components, their molecular weights arranged from 98 000 to 10 000. The gliadins form a heterogeneous but homologous group of polypeptides with an average molecular weight of 35 000. The albumins consist of components with molecular weights lower than 15 000.     

Optimizing the coagulation process in a drinking water treatment plant -- comparison between traditional and statistical experimental design jar tests

In this study of coagulation operation, a comparison was made between the optimum jar test values for pH, coagulant and coagulant aid obtained from traditional methods (an adjusted one-factor-at-a-time (OFAT) method) and with central composite design (the standard design of response surface methodology (RSM)). Alum (coagulant) and polymer (coagulant aid) were used to treat a water source with very low pH and high aluminium concentration at Sri-Gading water treatment plant (WTP) Malaysia. The optimum conditions for these factors were chosen when the final turbidity, pH after coagulation and residual aluminium were within 0-5 NTU, 6.5-7.5 and 0-0.20 mg/l respectively. Traditional and RSM jar tests were conducted to find their respective optimum coagulation conditions. It was observed that the optimum dose for alum obtained through the traditional method was 12 mg/l, while the value for polymer was set constant at 0.020 mg/l. Through RSM optimization, the optimum dose for alum was 7 mg/l and for polymer was 0.004 mg/l. Optimum pH for the coagulation operation obtained through traditional methods and RSM was 7.6. The final turbidity, pH after coagulation and residual aluminium recorded were all within acceptable limits. The RSM method was demonstrated to be an appropriate approach for the optimization and was validated by a further test.     

Steady state multiplicity in surface reactions with coverage dependent parameters

Surface reaction rates may not be unique even when gas pressure and composition above an isothermal catalytic surface are constant. In this paper we examine general ways of obtaining necessary and sufficient conditions for multiple reaction rates for mechanisms that include coverage dependent rate parameters, surface heterogeneity or formation of a complex compound between two reactants or between a reactant and a product. It is shown that variations of the reaction activation energy or heat of adsorption with coverage can enlarge regions of rate multiplicity. Several numerical examples are studied in detail.     

A GENERAL THEORY OF ANISOTROPIC MEMBRANES†

The theory of composite membranes with one “active” layer whose permeability varies with solute concentration is developed. The case of exponential dependence of permeability on concentration is treated in detail, but the case of a general dependence follows the same pattern and leads to the treatment of multi-layered membranes.     

An investigation of yield surfaces based on dislocation mechanics—II: Application

The yield criterion and hardening law proposed in Part I are used to calculate the first and second subsequent yield surfaces of aluminium. The obtained yield surfaces exhibit the following features: They shrink in the direction of prestressing, they show a rounded vertex near the prestress point, they become inflated on the side of prestress and deflated on the opposite side, and finally they may exclude the origin.     

On the influence of building design,occupants and heat waves on comfort and greenhouse gas emissions in naturally ventilated offices. A study based on the EN 15251 adaptive thermal comfort model in Athens,Greece

According to the Intergovernmental Panel on Climate Change the buildings sector has the largest mitigation potential for CO₂ emissions. Especially in office buildings, where internal heat loads and a relatively high occupant density occur at the same time with solar heat gains, overheating has become a common problem. In Europe the adaptive thermal comfort model according to EN 15251 provides a method to evaluate thermal comfort in naturally ventilated buildings. However, especially in the context of the climate change and the occurrence of heat waves within the last decade, the question arises, how thermal comfort can be maintained without additional cooling, especially in warm climates. In this paper a parametric study for a typical cellular naturally ventilated office room has been conducted, using the building simulation software EnergyPlus. It is based on the Mediterranean climate of Athens, Greece. Adaptive thermal comfort is evaluated according to EN 15251. Variations refer to different building design priorities, and they consider the variability of occupant behaviour and internal heat loads by using an ideal and worst case scenario. The influence of heat waves is considered by comparing measured temperatures for an average and an exceptionally hot year within the last decade. Since the use of building controls for shading affects thermal as well as visual comfort, daylighting and view are evaluated as well. Conclusions are drawn regarding the influence and interaction of building design, occupants and heat waves on comfort and greenhouse gas emissions in naturally ventilated offices, and related optimisation potential.     

Environmental assessment of brick production in Greece

Brick constitutes one of the major materials used for the construction of buildings. The present study analyses the different stages followed during brick production and the materials and energy used in each stage. The purpose is to identify ‘hot-spots’, i.e. parts of the life cycle that are important to the total environmental impact. The analysis is performed using life cycle assessment (LCA) methodology, which is a method used to identify and quantify the environmental performance of a process or a product from “cradle to grave”. LCA methodology provides a quantitative basis for assessing potential improvements in environmental performance of a system throughout the life cycle. The system investigated includes raw material acquisition, industrial production, packaging and transportation. Energy use and emissions are quantified and the potential environmental effects are assessed. The main energy inputs to the production system are electricity, diesel and solid fuel (Pet-Coke). The environmental burdens that arise from the operation of a brick industry are mainly due to air emissions derived from fossil fuel utilization.     

Polyphenols,carotenoids, and ascorbic acid in underutilized medicinal vegetables

The polyphenols, carotenoids, ascorbic acid, and protein were determined in 24 underutilized medicinal vegetables from Indonesia. Anacardium occidentale, Sauropus androgynus (L.) Merr., and Moringa pterygosperma Gaertn. leaves were rich sources of flavonoids, with 118–144 mg/100 g fresh weight. Quercetin, kaempferol, and chlorogenic acid were the predominant polyphenols among those measured in vegetables. Polyscias pinnata leaves and Solanum torvum Swartz fruits had the most phenolic acids, with 53 and 36 mg/100 g, respectively. Moringa pterygosperma had the most carotenoids among vegetables, with 14 mg β-carotene equivalents (βCE)/100 g. Ascorbic acid content of fresh vegetables was 12.03–494.43 mg/100 g. A. occidentale, S. androgynus, Ocimum americanum L., Cosmos caudatus H.B.K., and Carica papaya L. (papaya) leaves had more than 100 mg ascorbic acid/100 g. Thus, a number of underutilized vegetables from Indonesia may be rich sources of functional components including polyphenols and ascorbic acid.     

Passive vibration control of an offshore floating hydrostatic wind turbine model

We propose to make use of the hydraulic reservoir of a floating barge hydrostatic wind turbine (HWT) to suppress the pitch and roll motions of the barge by making the reservoir into a shape of an annular rectangular to serve as a bidirectional tuned liquid column damper (BTLCD). This means that we have made a barge‐motion damper with negligible extra costs as an HWT needs a reservoir for fluid storage anyway. The barge HWT simulation model is transformed from the NREL (National Renewable Energy Laboratory) 5‐MW geared equipped ITI Energy barge wind turbine model within the FAST (fatigue, aerodynamics, structures, and turbulence) code by replacing its drivetrain with a hydrostatic transmission drivetrain and incorporating the coupled dynamics of the barge‐reservoir system. We use 2 simplified turbine‐reservoir models to optimize the parameters of the BTLCD reservoir, which describe the pitch and roll motions of the turbine‐reservoir system, respectively. Simulation results based on the transformed NREL 5‐MW barge HWT model show that the optimal BTLCD reservoir is very effective in mitigating pitch and roll motions of the barge under realistic wind and wave excitations, which reduces the tower load and improves the power quality.     

Direct injection of hydrogen, oxygen and water in a novel two stroke engine

This short communication proposes novel two stroke engine burning hydrogen in oxygen in presence of large amounts of steam as residual gases. This engine has a bowl-in-piston combustion chamber, exhaust valves only and it uses direct injection of hydrogen, oxygen and water. Diesel-like compression ignition combustion is achieved by injecting the oxygen and the hydrogen in the surrounding steam close to a continuously operated glow plug. The operation of the engine is simulated by commercial softwares. The water injection enables acceptable metal temperatures and reduced heat losses. First computational results show brake efficiencies above 55% achieved with mass of water injected about twice the mass of oxygen and hydrogen mixture and operation with a significant amount of exhaust gas recirculation. It seems reasonable to guess efficiencies of the fully optimised and developed engine approaching the 60% mark, 20% higher than those of the state-of-the-art H₂ICEs designed for operation with air using the spark-ignition engine concept as well as of those projected for Diesel engines operating with exhaust energy recovery. Worth of mention is also the much higher power density following the two stroke operation.