Computation of the loading diagram and the tensile strength of carbon nanotube networks

A modification is suggested to the Brenner potential cut-off function in order to compute atomic forces of carbon nanostructures in a more realistic way and giving a possibility to fit the atomic forces to experimental data. With the modified Brenner potential, the loading diagram and the tensile strength were determined for an example of the carbon nanotube networks. According to these new computational results carbon nanotube networks can be the materials which inherit the extremely high strength of the graphite sheet and they bring this property in all directions of the 3D space (not only in one direction as the nanotubes).     

Effects of particle nonsphericity and radiation polarization on retrieving dust properties from MODIS observations

The scattering and radiative properties of mineral dust aerosols at violet-to-blue (0.412, 0.441, and 0.470 μm) and red (0.650 μm) wavelengths are investigated. To account for the effect of particle nonsphericity on the optical properties of dust aerosols, in the present study, these particles are assumed to be spheroids. A combination of the T-matrix method and an improved geometric optics method is applied to the computation of the single-scattering properties of spheroidal particles with size parameters ranging from the Rayleigh to geometric optics regimes. For comparison, the Lorenz–Mie theory is employed to compute the optical properties of spherical dust particles that have the same volumes as their nonspherical counterparts. The differences between the phase functions of spheroidal and spherical particles lead to quite different lookup tables involved in retrieving dust aerosol properties. Moreover, the applicability of a hybrid approach based on the spheroid model for the phase function and the sphere model for the other phase matrix elements is also demonstrated. The present sensitivity study, employing the moderate resolution imaging spectroradiometer (MODIS) measurements and the fundamental principle of the Deep Blue algorithm, illustrates that neglecting the nonsphericity of dust particles usually leads to an underestimate of retrieved aerosol optical depth; although, depending on the scattering angle, an overestimate is noted in some cases. Furthermore, the effect of including full polarization treatment in forward radiative transfer simulation on dust property retrieval is also investigated. It is found that the effect of radiation polarization on the Deep Blue dust property retrieval is not negligible if the retrieval is based on two violet—blue channels centered at 0.412 and 0.470 μm.     

Entwicklungsstand und Anwendungsfelder von Nachhaltigkeitskennzahlen für die Stahlindustrie

Applicability of sustainability indicators — List of IISI — Summarizing considerations — Sustainability as a strategic leadership element by balanced score card — Sustainability management in the materials’ industry     

The effect of particle shape on the activity of nanocrystalline TiO2 photocatalysts in phenol decomposition

Nanosized TiO₂ photocatalysts were synthesized via hydrogen–air flame hydrolysis. X-ray diffraction (XRD) measurements revealed that the TiO₂ samples thus prepared consisted mainly of anatase (79–98 wt%) and the rest is rutile. Average particle diameters from TEM measurements were found to vary between 48 and 63 nm. The specific surface area of the samples was found to be practically independent of the synthesis parameters employed (20–32 m² g⁻¹). Photocatalytic activity of the catalysts was studied by using various model compounds. In spite of their very similar properties, the initial decomposition rate of phenol and methanol showed up to threefold variations within the series of the samples, and it was significantly higher for the best catalyst than that determined for Degussa P25. Our TEM measurements demonstrated that in the less active catalysts the dominant morphology of the particles is spherical, while polyhedral (cubic or hexagonal) shapes predominate in the samples with superior photocatalytic activity. From these observations, we concluded, that the shape of the primary particles (both in the case of our home made ones and in various batches of Degussa P25) strongly influence the photocatalytic activity of titania nanoparticles.     

A genetic algorithm that exchanges neighboring centers for k-means clustering

We present a genetic algorithm for selecting centers to seed the popular k-means method for clustering. Using a novel crossover operator that exchanges neighboring centers, our GA identifies superior partitions using both benchmark and large simulated data sets.     

Correlation of chromatographic absolute loss determinations with the A.O.C.S. Cup Refining method in soybean oil

Summary It can be concluded, on the basis of our experiments, that chromatographic loss determinations can be well correlated with A.O.C.S. Cup Refining determinations. This correlation is good for samples above 1% chromatographic losses and somewhat less accurate for samples below 1.0%. Most of the discrepancy in correlation is inherent in the Cup Loss method because it is less precise in general than the chromatographic determination. On the other hand, the chromatographic loss is an accurate, easily obtainable index for unavoidable losses resulting from the nonneutral oil fraction of the oils. In the majority of cases the degumming of the oil to levels below 1% chromatographic loss is not indicated by a parallel decrease in cup losses. Thus, in these cases, as long as premiums are paid on the basis of the A.O.C.S. Cup Loss method, the processor is placed in a very disadvantageous position. It should be pointed out that all our determinations were made on the oils from the 1956 crop during the summer months. The possibility that different crop years will result in different correlation curves might exist, and we are planning to do further work in the future. It is hoped that by presenting statistically significant figures on this subject, enough interest will be stimulated for more collaborative work, which might result in a review of the industry's present method for the determination of refining losses in soybean oil.     

A new method for quantitative determination of BHA

A qualitative test developed by Laszlo has been adapted to the quantitative determination of BHA. The determination is based on measurement of the specific and sensitive color resulting from reaction of BHA with diazotized sulfanilic acid in alkaline solution. The red-purple color, which is stable for long periods, has an absorption maximum at 535 mμ. Beer’s law is obeyed, and a concentration range of 0.0001% to 0.01% BHA may be measured. The method requires careful adjustment of antioxidant-reagent ratios for rapid and maximum color development, The optimum ratios, the effect of alcohol, and interfering substances are diseussed. The method, as described, also provides for an accurate specific determination of BHA in fats and oils even when other antioxidants are present. Journal Pager No. 184, American Meat Institute Foundation. Presented at 50th Anniversary Meeting, American Oil Chemists’ Society, April 20–22, 1959, New Orleans, La. Chemist in the Division for Inspection of Animal Products (D.I.P.O.A.) of the Ministry of Agriculture (Rio de Janeiro, Brazil) and American Association of University Women Fellow at the American Meat Institute Foundation during 1958–59.     

New image analysis methods for the study of mixing patterns in stirred tanks

A method of treating data acquired with the planar laser‐induced fluorescence technique has been developed to visualize the topology of two‐dimensional concentration fields and to describe the dynamics of the coherent mixing structures identified. This method is based on a conditional binary transformation of the local concentration data, combined with a joint probability calculation. The methodology has been used to investigate the mixing in a stirred tank, at two injection port locations (in the bulk and in the impeller stream region). With bulk injection, a “folding phenomenon” of the coherent mixing structure was detected. Away from this port, large‐scale spatially periodic motion was identified, with a characteristic time of oscillation of the order of 2 to 3 s. With injection in the impeller stream region, no spatial instabilities of the coherent structure were detected. Local oscillations of the coherent mixing structure were found both on short and long time‐scales (i.e., ?1 and ?80 s).     

An Exploratory Evaluation of Tyrosine Hydroxylase Inhibition in Planaria as a Model for Parkinsonism

Planaria are the simplest organisms with bilateral symmetry and a central nervous system (CNS) with cephalization; therefore, they could be useful as model organisms to investigate mechanistic aspects of parkinsonism and to screen potential therapeutic agents. Taking advantage of the organism’s anti-tropism towards light, we measured a significantly reduced locomotor velocity in planaria after exposure to 3-iodo-l-tyrosine, an inhibitor of tyrosine hydroxylase that is an enzyme catalyzing the first and rate-limiting step in the biosynthesis of catecholamines. A simple semi-automatic assay using videotaped experiments and subsequent evaluation by tracking software was also implemented to increase throughput. The dopaminergic regulation of locomotor velocity was confirmed by bromocriptine, a drug whose mechanisms of action to treat Parkinson’s disease is believed to be through the stimulation of nerves that control movement.