Some practical aspects connected with the presence of calcium in soybean oils

Presence of calcium in crude and degummed soybean oils prevents complete elimination of phosphatides by hydration and enhances the formation of heavy precipitates. They block industrial centrifuges at the later stages of the refining processes. Industrially extracted degummed soybean oils contain appreciable amounts of calcium (ca. 100 ppm) and its source was traced to the processed soybeans. Various pre-extraction treatments of the soybeans in industry augment the calcium content in the oils, since crude Soxhlet-extracted soybean oils contained only 15 ppm calcium. Additions at the alkali-refining stages of EDTA or of polyphosphate, to stabilize aqueous suspensions which also contain calcium salts, are suggested as a partial remedy to the frequent blocking of the centrifuges.     

An Experimental Approach for the Characterisation of Rigid Porous Media and Unsaturated Conductivity Relations

A laboratory procedure for the characterisation of rigid, porous media is developed and tested. The overall objective of the characterisation is to provide a basis for the choice of a relevant unsaturated conductivity relation. With the proposed procedure, the porous materials are characterised through hydraulic conductivity measurements, saturation-pressure measurements, porosity measurements and air entry pressure measurements. The measurements were conducted using water and a selected non-aqueous phase liquid (n-decane), and two types of homogeneous, rigid porous media of different origin (fritted glass samples with guaranteed homogeneity by the manufacturer, and chalk). The laboratory method successfully characterised the fritted glass samples as homogeneous on basis of calculated tortuosity values, measured bubble pressures and measured pore-size density curves. The contact angle between the liquid and the solid had negligible impact when comparing the drainage of water with the drainage of n-decane, and also when comparingn -decane drainage in dry porous media withn -decane drainage in media where a film of water separated then -decane from the pore wall. Also, the differences in saturated conductivities between n-decane and water in both samples of chalk and fritted glass were well predicted on basis of differences in density and viscosity of the liquids. The laboratory procedure was furthermore used for characterisation of the pore space available for non-aqueous liquid flow in partially water-saturated porous media. Then -decane conductivities in the fritted glass samples partially saturated with water were considerably lower than the n-decane conductivities in the dry fritted glass samples.     

External sorting on flash storage: reducing cell wearing and increasing efficiency by avoiding intermediate writes

This paper studies the problem of how to conduct external sorting on flash drives while avoiding intermediate writes to the disk. The focus is on sort in portable electronic devices, where relations are only larger than the main memory by a small factor, and on sort as part of distributed processes where relations are frequently partially sorted. In such cases, sort algorithms that refrain from writing intermediate results to the disk have three advantages over algorithms that perform intermediate writes. First, on devices in which read operations are much faster than writes, such methods are efficient and frequently outperform Merge Sort. Secondly, they reduce flash cell degradation caused by writes. Thirdly, they can be used in cases where there is not enough disk space for the intermediate results. Novel sort algorithms that avoid intermediate writes to the disk are presented. An experimental evaluation, on different flash storage devices, shows that in many cases the new algorithms can extend the lifespan of the devices by avoiding unnecessary writes to the disk, while maintaining efficiency, in comparison with Merge Sort.     

Capacitance voltage characterization of poly SiSiO2Si structures

The high frequency C-V characteristics of poly SiSiO₂Si capacitors have been studied. It is shown that the poly SiSiO₂Si capacitor C-V characteristics are significantly different from the corresponding metal-SiO₂Si capacitor due to field penetration into the poly Si layer. A comparison of the theoretical and measured C-V characteristics gives an estimate of the surface state charge density at the poly SiSiO₂ interface and indicates that the surface potential behavior of this interface is trap and surface state dominated up to poly silicon impurity concentrations of approximately 10¹⁷ cm^?3.     

Performance and stability of communication networks via robustexponential bounds

A method for evaluating the performance of packet switching communication networks under a fixed, session-based, routing strategy is proposed. The approach is based on properly bounding the probability distribution functions of the system input processes. The suggested bounds which are decaying exponentials, possess three convenient properties. When the inputs to an isolated network element are all bounded, they result in bounded outputs and assure that the delays and queues in this element have exponentially decaying distributions. In some network settings, bounded inputs result in bounded outputs. Natural traffic processes can be shown to satisfy such bounds. Consequently, this method enables the analysis of various previously intractable setups. Sufficient conditions are provided for the stability of such networks, and derive upper bounds for the parameters of network performance are derived     

On the Effective Deployment of Functional Formal Verification

We examine IBM's exploitation of formal verification using RuleBase—a formal verification tool developed by the IBM Haifa Research Laboratory. The goal of the paper is methodological. We identify an integrated methodology for the deployment of formal verification which involves three complementary modes: architectural verification, block-level verification, and design exploration.     

Study of DNA Origami Dimerization and Dimer Dissociation Dynamics and of the Factors that Limit Dimerization

Organizing DNA origami building blocks into higher order structures is essential for fabrication of large structurally and functionally diverse devices and molecular machines. Unfortunately, the yields of origami building block attachment reactions are typically not sufficient to allow programed assembly of DNA devices made from more than a few origami building blocks. To investigate possible reasons for these low yields, a detailed single‐molecule fluorescence study of the dynamics of rectangular origami dimerization and origami dimer dissociation reactions is conducted. Reactions kinetics and yields are investigated at different origami and ion concentrations, for different ion types, for different lengths of bridging strands, and for the “sticky end” and “weaving welding” attachment techniques. Dimerization yields are never higher than 86%, which is typical for such systems. Analysis of the dynamic data shows that the low yield cannot be explained by thermodynamic instability or structural imperfections of the origami constructs. Atomic force microscopy and gel electrophoresis evidence reveal self‐dimerization of the origami monomers, likely via blunt‐end interactions made possible by the presence of bridging strands. It is suggested that this mechanism is the major factor that inhibits correct dimerization and means to overcome it are discussed.     

Nanoparticles of CdCl2 with closed cage structures

Nanoparticles of various layered compounds having a closed cage or nanotubular structure, designated also inorganic fullerene-like (IF) materials, have been reported in the past. In this work IF-CdCl₂ nanoparticles were synthesized by two methods. In one technique, a high temperature evaporation and subsequent condensation of dried cadmium chloride powder was used. In the other method, electron beam irradiation of the source powder led to its recrystallization into closed nanoparticles with a nonhollow core. The two methods are shown to produce nanoparticles of different topologies. While mostly spherical nested structures are obtained from the high temperature process, polyhedra with hexagonal or elongated rectangular characters are obtained by the electron beam induced process. The analysis also shows that, while the source (dried) powder is orthorhombic cadmium chloride monohydrate, the crystallized IF cage consists of the anhydrous 3R polytype which is not stable as bulk material in ambient atmosphere. Consistent with previous observations, this study shows that the seamless structure of the IF materials can stabilize phases, which are otherwise unstable in ambient conditions.     

Visually evoked cerebral vasomotor response in smoking and nonsmoking young adults, investigated by functional transcranial Doppler

Smoking has been known to cause endothelial dysfunction and is an important risk factor for ischemic stroke. In our study we investigated whether chronic cigarette smoking affects the cerebral blood flow velocity response to a physiological, visual stimulus. By using a visual cortex stimulation paradigm, the flow velocity response in the posterior cerebral arteries (PCA) was measured bilaterally, in 32 young healthy adults (16 smokers, 16 nonsmokers). The stimulation protocol consisted of 10 cycles with a resting phase of 20 s and a stimulating phase of 40 s for each cycle. Besides functional transcranial Doppler (TCD), laboratory tests and measurement of intima-media-thickness (IMT) were also performed. Repeated-measure analysis of variance (ANOVA) was used to detect differences in visually evoked relative flow velocity time courses between smokers and nonsmokers. Repeated-measure ANOVA revealed marked difference in the peak systolic flow velocity time courses between smokers and nonsmokers (p< .001). Maximum percent change of visually evoked flow velocity after visual stimulation was 19+/-4% and 30+/-3% in smokers and nonsmokers, respectively (p< .0001). IMT values did not indicate atherosclerosis in young smokers. Infectious disease and hyperlipidemia were also ruled out by measurement of sensitive C-reactive protein and serum lipids. This is the first functional TCD study demonstrating impaired visually evoked flow velocity response caused by chronic cigarette smoking in otherwise healthy, young subjects. The impaired cerebral vasodilatory mechanism together with atherosclerosis may influence stroke occurrence and outcome in chronic smokers.