Correlative and predictive models of viscosity study on Propiophenone with isomeric xylenes binary mixtures at <Emphasis Type="Italic">T</Emphasis>=(303.15 to 318.15) K

Densities and viscosities of binary mixtures of Propiophenone with o-xylene, m-xylene and p-xylene were measured over the entire composition range at T=(303.15 to 318.15) K and at 0.1Mpa atmospheric pressure. Experimental data used to calculate excess molar volume (V^E), deviation of viscosity (Δη), excess Gibb’s free energy (G^*E) activation of viscous flow for each binary system and the results were fitted to the Redlich-Kister polynomial equation to obtain the fitting coefficients and standard deviations. Viscosity values used to compute single adjustable interaction parameters from Grunberg and Nissan, Katti and Chaudhri, Hind et al., Tamara Kurata and Frenkel relations. Deviations in thermodynamic properties of the binary mixtures were discussed in terms of their molecular interactions between the components. Viscosity data correlated with the McAllister’s three body/four body models, Heric, Auslander, and Jouyban-Acree relations having two and three adjustable parameters for the studied binary mixtures. Viscosity relations like Kendall-Monroe, Bingham, Arrhenius, and Kendall were used to calculate and compare the standard deviation percentage, (σ %), between the experimental and calculated viscosity data. The studied systems showed specific intermolecular interactions and the percentage deviations were in good agreement with the experimental values. Obtained results are useful in various chemical and industrial processes.     

Human behavior in fires—a review of research in the United Kingdom

In recent years research into human behavior in fires has been carried out in several countries for improving provisions for life safety currently prescribed in firesafety codes. This technical note reviews briefly the findings of human behavior studies in the United Kingdom with particular reference to buildings with a large number of people at risk. According to one of the main conclusions of this paper, for successful evacuation, early detection should be followed by timely and convincing communication to building occupants information about the existence, location, and spread of fire. This can be achieved by computer-based informative fire warning systems, which is the subject matter of another technical note.     

Ultra-large-scale directed assembly of single-walled carbon nanotube devices

One of the biggest limitations of conventional carbon nanotube device fabrication techniques is the inability to scale up the processes to fabricate a large number of devices on a single chip. In this report, we demonstrate the directed and precise assembly of single-nanotube devices with an integration density of several million devices per square centimeter, using a novel aspect of nanotube dielectrophoresis. We show that the dielectrophoretic force fields change incisively as nanotubes assemble into the contact areas, leading to a reproducible directed assembly which is self-limiting in forming single-tube devices. Their functionality has been tested by random sampling of device characteristics using microprobes.     

Influence of structural and dielectric anisotropy on the dielectrophoresis of single-walled carbon nanotubes

We report on a carbon nanotube network which is composed of aligned metallic and randomly oriented semiconducting single-walled carbon nanotubes. The material is formed by using a novel radio frequency dielectrophoresis setup, which generates very large dielectrophoretic force fields and allows dielectrophoretic assembling of nanotube films up to 100 nm thickness. Polarization dependent absorption measurements provide experimental evidence for the electronic type specific alignment behavior. We explain the experimental data with an advanced model for nanotube dielectrophoresis, which explicitly takes into account both the longitudinal and transversal polarizability. On the basis of this model, we calculate the dielectrophoretic force fields and show that semiconducting nanotubes deposit under very large fields due to their transversal polarizability even for high field frequencies.     

Fenton-enhanced gamma-radiolysis of cyanuric acid

Degradation of cyanuric acid (OOOT), a stable end product of oxidative decomposition of atrazine, is investigated in a combined field of gamma radiolysis and fenton reaction. The reaction of hydroxyl radical (OH) at pH 6 was carried out by irradiating N(2)O saturated aqueous solutions containing OOOT (1 x 10(-3) mol dm(-3)), and this resulted only a marginal degradation (20%). However, when the same reaction was carried out in the presence of varying concentrations of ferrous sulfate ((5-10)x10(-5) mol dm(-3)), the decay of OOOT has been enhanced to more than 80%. This decay followed a first order kinetics. Nearly similar effects were observed with another triazine derivative, 2,4-dioxohexahydro-1,3,5-triazine (DHT). Two major reaction mechanisms are proposed for the enhanced decay of OOOT. The formation of unstable hydroxyl radical adducts from the reaction of .OH which is the result of gamma radiolysis and the Fenton reaction (resulting from the reaction of the added Fe(II) and of the H(2)O(2) from the radiolysis of water), is proposed as the first mechanism. The second mechanism, which is likely the major contributor to degradation, is proposed as the reaction of a nucleophilic adduct, Fe(II)OOH, which could directly react with the electron deficient triazine ring. It is highlighted that such degradation reactions must be explored for the complete degradation of the byproducts of the oxidative decomposition of atrazine.     

Probabilistic approach to fire risk evaluation

Probabilistic techniques offer rational methods of dealing with the randomness of fire risk and effectiveness of firesafety measures. In this paper the state of the art in these techniques is reviewed with examples illustrating the use of fire statistics in evaluating the parameters of these models. Methods discussed include exponential model of fire growth, probability distribution of damage, and stochastic model of fire spread. The estimates provided by these models can be used in conjunction with an engineering method for a probabilistic treatment of deterministic predictions.     

Free and bound triacontanol in tea leaves

A direct gas chromatographic method of identification and determination of 1-triacontanol, a plant growth substance, in tea leaves is reported. Treatment of the tea leaves with calcium oxide releases more triacontanol, showing that the compound occurs also in a bound form in tea leaves.     

Enhanced sensitivity of lateral flow tests using a two-dimensional paper network format

Point-of-care diagnostic assays that are rapid, easy-to-use, and low-cost are needed for use in low-resource settings; the lateral flow test has become the standard bioassay format in such settings because it meets those criteria. However, for a number of analytes, conventional lateral flow tests lack the sensitivity needed to have clinical utility. To address this limitation, we are developing a paper network platform that extends the conventional lateral flow test to two dimensions. The two-dimensional structures allow incorporation of multistep processes for improved sensitivity, while still retaining the positive aspects of conventional lateral flow tests. Here we create an easy-to-use, signal-amplified immunoassay based on a modified commercial strip test for human chorionic gonadotropin, the hormone used to detect pregnancy, and demonstrate an improved limit of detection compared to a conventional lateral flow assay. These results highlight the potential of the paper network platform to enhance access to high-quality diagnostic capabilities in low-resource settings in the developed and developing worlds.     

Polymorphism of amyloid β peptide in different environments: implications for membrane insertion and pore formation

Amyloid-β (Aβ) peptides are thought to be involved in neurodegenerative diseases such as Alzheimer's disease and Down's syndrome. They form a large number of polymorphic structures, including heterogeneous ionic pores in membranes as well as different types of fibrillar and globular structures on surfaces and in solution. Understanding the origin of these structures and the factors that influence their occurrence is of great biomedical interest because of the possible relationship between structure and pathogenicity. Here, we use atomic force microscopy (AFM) and molecular dynamics (MD) simulations to demonstrate that at room temperature a truncated Aβ peptide which is generated in vivo and shown to be toxic in vitro forms fibrillar structures on hydrophobic graphite surfaces, but not on hydrophilic mica or lipid bilayers. Our results suggest that the toxic pores and fibrillar polymorphic organizations can be explained in terms of the U-shaped β-strand-turn-β-strand structural motif observed for full length Aβ and other amyloids, as well as the physicochemical properties at the interfaces. The interactions of the hydrophobic, truncated Aβ with its environment illustrate that the universal amyloid motif can provide a link between the pore and fibrillar structures and indicate that surfaces with different physicochemical properties can shift the polymorphic landscape toward other conformational states.     

Bi- and trilayer graphene solutions

Bilayer and trilayer graphene with controlled stacking is emerging as one of the most promising candidates for post-silicon nanoelectronics. However, it is not yet possible to produce large quantities of bilayer or trilayer graphene with controlled stacking, as is required for many applications. Here, we demonstrate a solution-phase technique for the production of large-area, bilayer or trilayer graphene from graphite, with controlled stacking. The ionic compounds iodine chloride (ICl) or iodine bromide (IBr) intercalate the graphite starting material at every second or third layer, creating second- or third-stage controlled graphite intercolation compounds, respectively. The resulting solution dispersions are specifically enriched with bilayer or trilayer graphene, respectively. Because the process requires only mild sonication, it produces graphene flakes with areas as large as 50 μm(2). Moreover, the electronic properties of the flakes are superior to those achieved with other solution-based methods; for example, unannealed samples have resistivities as low as ～1 kΩ and hole mobilities as high as ～400 cm(2) V(-1) s(-1). The solution-based process is expected to allow high-throughput production, functionalization, and the transfer of samples to arbitrary substrates.