Observations of Twelve USEPA Priority Polycyclic Aromatic Hydrocarbons in the Aitken Size Range (10–32 nm D p )

Particle size distribution measurements of twelve USEPA priority pollutant polycyclic aromatic hydrocarbons (PAHs)—collected in Riverside, California, down to 10 nm aerodynamic diameter (D_p)—observed on integrated nocturnal samples (7:00 p.m.-6:30 a.m.) revealed that between 46 and 100% of the mass of particles in the Aitken size range was found in the 10–18 nm size bin. Particles in this size range have high alveolar deposition efficiency.     

The Density of States and the Pertinent Electronic Properties of the Quasi 2DEG in Simple and DMS Structures Subjected to an In-Plane Magnetic Field

We analyze the important changes induced to the density of states (DOS) of a quasi two-dimensional-electron-gas (2DEG), when it is subjected to an in-plane magnetic field, B. The DOS diverges significantly from the famous step-like form and this introduces changes to the pertinent electronic properties. In order to calculate the DOS it is indispensable to use a self-consistent approach. The eigenvalue problem has to be solved for each subband index i and in-plane wavevector, k _x, when the quasi 2DEG is parallel to the xy-plane and B is applied along the y-axis. Although the modification of the DOS is usually ignored, we show here that not only the general shape of the DOS varies, but this effect is also quantitative.     

Rheological behaviour of multiphase slurries for combustion applications

The rheological behaviour of a concentrated coal-water-fuel oil slurry was investigated with a tube viscometer, to optimize its formulation. The non-Newtonian character of the slurry follows the rheological model of Ostwald de Waele, according to the experimental results obtained. A factorial plan was used and empirical equations were obtained which correlate rheological characteristics with the mass fractions of the slurry components.     

A linear model predictive control algorithm for nonlinear large‐scale distributed parameter systems

This work provides a framework for linear model predictive control (MPC) of nonlinear distributed parameter systems (DPS), allowing the direct utilization of existing large‐scale simulators. The proposed scheme is adaptive and it is based on successive local linearizations of the nonlinear model of the system at hand around the current state and on the use of the resulting local linear models for MPC. At every timestep, not only the future control moves are updated but also the model of the system itself. A model reduction technique is integrated within this methodology to reduce the computational cost of this procedure. It follows the equation‐free approach (see Kevrekidis et al., Commun Math Sci. 2003;1:715–762; Theodoropoulos et al., Proc Natl Acad Sci USA. 2000;97:9840‐9843), according to which the equations of the model (and consequently of the simulator) need not be given explicitly to the controller. The latter forms a “wrapper” around an existing simulator using it in an input/output fashion. This algorithm is designed for dissipative DPS, dissipativity being a prerequisite for model reduction. The equation‐free approach renders the proposed algorithm appropriate for multiscale systems and enables it to handle large‐scale systems. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Energy resources' utilization in organic and conventional vineyards: Energy flow, greenhouse gas emissions and biofuel production

An energy analysis, in conventional and organic vineyards, combined with ethanol production and greenhouse gas emissions, is useful in evaluating present situation and deciding best management strategies. The objective of this study was to evaluate the differences in the energy flow between organic and conventional vineyards in three locations, to calculate CO₂, CH₄ and N₂O-emissions based on the used fossil energy and to explore if wine industry wastes can be used to extract bioethanol. The data were collected through personal interviews with farmers during 2004–2005. Eighteen farmers, who owned vineyards about 1 ha each, were randomly selected to participate in this study [(3 conventional and 3 organic) × 3 locations]. The means averaged over all locations for fertilizer application, plant protection products application, transportation, harvesting, labor, machinery, fuels, plant protections products and tools energy inputs, total energy inputs, outputs (grapes), outputs (grapes + shoots), grape yield, man hour, pomace and ethanol from pomace were significantly higher in conventional than in organic vineyards, while the opposite occurred for the pruning. Means averaged over two farming systems for harvesting, tools energy inputs, energy outputs (grapes), grape yield, pomace and ethanol from pomace were significantly higher at location A, followed by location C and location B. Finally, for irrigation, the means averaged over the two farming systems were significantly lower at location C. Greenhouse gas emissions were significant lower in organic than in conventional vineyards. The results show a clear response of energy inputs to energy outputs that resulted from the farming system and location.     

Studies on the chemical, physical and mechanical properties of high-solids clearcoats prepared from hydroxyl-terminated isophthalate-based oligoesters and a melamine resin

A series of high-solids (solvent-free) clearcoats was prepared from hydroxyl-terminated isophthalate-based oligoesters and the hexakis(methoxymethylol)melamine resin (HMMM). The oligoesters, which were used as binders, were prepared via a transesterification reaction of dimethyl isophthalate (DI) under various molar ratios R (=mol ratio diols/diester) with a mixture of 1,6-hexanediol (HD) and 2-methyl-1,3-propanediol (MP). Mixtures of the two diols of different composition R_d (=mol ratio HD/MP), were used as well. An attempt was made to investigate and correlate the chemical, physical and mechanical properties of the formulated solvent-free clearcoats to: (a) the amount of the cross-linker (melamine resin); (b) the curing conditions (time and temperature); (c) the synthetic parameters applied in the preparation (via transesterification) of the oligoesters (e.g. excess of the diols in reaction with the DI and the molar ratio between the two diols, the species of the Lewis acid catalyst). The properties of all the new formulated high-solids clearcoats were compared to those of a reference clearcoat and their cross-linking was correlated to their chemical structure and composition as well as to their T_g values. It was found that the R and R_d values applied in the synthesis of the oligoesters (binders) significantly affected the performance of their corresponding clearcoats. More specifically, the clearcoats obtained from binders where 3<R<4, combined an enhanced processability, higher values of non-volatiles (80%) (lower VOC content) and better or comparable chemical, physical and mechanical properties (e.g. impact resistance, gasoline resistance, mar resistance, flexibility and pencil hardness) upon comparison to those of the reference clearcoat.     

Radical-scavenging activity of Aegean Sea marine algae

In the present work, thirteen algae from the Aegean Sea were examined for radical-scavenging activity (RSA) using the DPPH and chemiluminescence (CL) tests. Extracts of the brown alga Taonia atomaria exhibited the best RSA in comparison to the extracts of the other investigated species and approached the activity of powerful antioxidant standards. Column chromatography separation of T. atomaria extract, followed by preparative HPLC, resulted in the isolation of six metabolites, which were identified by spectral analyses (¹H NMR, ¹³C NMR and MS). The isolated metabolites taondiol, isoepitaondiol, stypodiol, stypoldione, sargaquinone and sargaol were found to possess marked RSA.     

Competitive displacement of oil body surface proteins by Tween 80 – Effect on physical stability

A concentrated oil body cream, prepared from maize germ by aqueous extraction, was dispersed in water to obtain a natural 5% o/w emulsion. To improve the emulsion physical stability, the hydrophilic surfactant Tween 80 (polyoxyethylene sorbitan monooleate) was incorporated at levels ranging from 0.25 to 2%, and the increase of the oil body mean diameter and the volume of serum separated from the emulsion system, was followed with storage time. In addition, the amount and composition of oil body surface proteins competitively displaced by the surfactant was studied. The improvement in oil body stability against coalescence and creaming, resulting from Tween addition, is discussed in terms of the development at the oil body surface of an adsorbed film of a mixed nature, made up of surfactant- and phospholipid-rich domains, with the non-displaced surfactant protein molecules, mainly oleosins, remaining embedded in the latter.     

A Microwave Coaxial Sensor for Non-Destructive Detection and Analysis of Cracked Teeth

Russian Journal of Nondestructive Testing - A new approach for the detection of cracks in a tooth is presented using a microwave coaxial sensor. In the test, the probe tip is in close contact with...