Monopolar Corona on Bundle Wires as Influenced by Wind

The measured corona current contributed by each subwire in various laboratory-size bundle models and the total corona current change with wind over a wide range of applied voltages are described. The lateral spacial distribution of the time-average value of windblown corona current over the ground plate is measured for different applied voltages and different bundle geometries. The obtained results are compared to previous findings and to theories of corona discharge.     

Safety assessment methodology in management of spent sealed sources

Environmental hazards can be caused from radioactive waste after their disposal. It was therefore important that safety assessment methodologies be developed and established to study and estimate the possible hazards, and institute certain safety methodologies that lead and prevent the evolution of these hazards. Spent sealed sources are specific type of radioactive waste. According to IAEA definition, spent sealed sources are unused sources because of activity decay, damage, misuse, loss, or theft. Accidental exposure of humans from spent sealed sources can occur at the moment they become spent and before their disposal. Because of that reason, safety assessment methodologies were tailored to suit the management of spent sealed sources. To provide understanding and confidence of this study, validation analysis was undertaken by considering the scenario of an accident that occurred in Egypt, June 2000 (the Meet-Halfa accident from an iridium-192 source). The text of this work includes consideration related to the safety assessment approaches of spent sealed sources which constitutes assessment context, processes leading an active source to be spent, accident scenarios, mathematical models for dose calculations, and radiological consequences and regulatory criteria. The text also includes a validation study, which was carried out by evaluating a theoretical scenario compared to the real scenario of Meet-Halfa accident depending on the clinical assessment of affected individuals.     

Bounded similarity querying for time-series data

We define the problem of bounded similarity querying in time-series databases, which generalizes earlier notions of similarity querying. Given a (sub)sequence S, a query sequence Q, lower and upper bounds on shifting and scaling parameters, and a tolerance , S is considered boundedly similar to Q if S can be shifted and scaled within the specified bounds to produce a modified sequence S′ whose distance from Q is within . We use similarity transformation to formalize the notion of bounded similarity. We then describe a framework that supports the resulting set of queries; it is based on a fingerprint method that normalizes the data and saves the normalization parameters. For off-line data, we provide an indexing method with a single index structure and search technique for handling all the special cases of bounded similarity querying. Experimental investigations find the performance of our method to be competitive with earlier, less general approaches.     

Protein-doped monolithic silica columns for capillary liquid chromatography prepared by the sol-gel method: applications to frontal affinity chromatography

The development of bioaffinity chromatography columns that are based on the entrapment of biomolecules within the pores of sol-gel-derived monolithic silica is reported. Monolithic nanoflow columns are formed by mixing the protein-compatible silica precursor diglycerylsilane with a buffered aqueous solution containing poly(ethylene oxide) (PEO, MW 10,000) and the protein of interest and then loading this mixture into a fused-silica capillary (150-250-microm i.d.). Spinodal decomposition of the PEO-doped sol into two distinct phases prior to the gelation of the silica results in a bimodal pore distribution that produces large macropores (>0.1 microm), to allow good flow of eluent with minimal back pressure, and mesopores (approximately 3-5-nm diameter) that retain a significant fraction of the entrapped protein. Addition of low levels of (3-aminopropyl)triethoxysilane is shown to minimize nonselective interactions of analytes with the column material, resulting in a column that is able to retain small molecules by virtue of their interaction with the entrapped biomolecules. Such columns are shown to be suitable for pressure-driven liquid chromatography and can be operated at relatively high flow rates (up to 500 microL x min(-1)) or with low back pressures (<100 psi) when used at flow rates of 5-10 microL x min(-1). The clinically relevant enzyme dihydrofolate reductase was entrapped within the bioaffinity columns and was used to screen mixtures of small molecules using frontal affinity chromatography with mass spectrometric detection. Inhibitors present in compound mixtures were retained via bioaffinity interactions, with the retention time being dependent on both the ligand concentration and the affinity of the ligand for the protein. The results suggest that such columns may find use in high-throughput screening of compound mixtures.     

Electrical properties of Cu(II) and Ni(II): N-salicylidene polymethacrylic acid hydrazide complexes

Different types of chelated polymer complexes have been synthesized to obtain improved electrical properties. Compact discs from powders of the chelated polymers were prepared and heated in a specially designed holder. Electrical conductivity and dielectric constant of Cu(II) and Ni(II): N-salicylidene polymethacrylic acid hydrazide samples were measured at a fixed frequency (1600 Hz) throughout the temperature range 25-150°C. The AC conductivity as well as dielectric measurements showed maxima at 85°C. The water molecules which were trapped in the polymer matrix are believed to play the main role in conduction and dielectric behaviour of the polymeric material. From the AC conductance and dielectric constant measurements, the dielectric losses of these polymeric materials were calculated as a function of temperature.     

The protective role of water injection on oil quality in deep fat frying conditions

The protective role of water injection on oil quality was studied in deep fat frying conditions. Oil stability indices included acid value (AV), malondialdehyde (MDA), p-anisidine, and conjugated dienes (CDs). Water was continuously injected at flow rates of 0.1 to 1.0 and 0.1 to 0.5 mL/min/L into corn and canola oil, respectively. Frying was conducted at 170 °C for up to 22 h. Water injection had a dual effect. In comparison with the control, water injection increased the AV of corn oil (from 0.09 to 0.59 mg/g) and canola oil (from 0.02 to 0.15 mg/g), and a contrarily protective role was found in all the other quality indices. Significant reductions in MDA concentration (from 1,600 to 497 ppb and 6,178 to 3,765 ppb), p-anisidine value (from 195 to 39 mmol/kg and 147 to 67 mmol/kg), and CDs (from 29 to 19 mM and 33 to 25 mM) were measured in corn and canola oil, respectively. MDA, p-anisidine and CD concentrations were higher when water was injected through a capillary of a wider diameter. Headspace air flow, or direct nitrogen injection were also significant factors affecting oil quality. The protective role of water stresses the need to consider this information for the extended frying applications expected in fast food outlets and restaurants.     

Optical transfer function shaping and depth of focus by using a phase only filter

The design of a desired optical transfer function (OTF) is a common problem that has many possible applications. A well-known application for OTF design is beam shaping for incoherent illumination. However, other applications such as optical signal processing can also be addressed with this system. We design and realize an optimal phase only filter that, when attached to the imaging lens, enables an optimization (based on the minimal mean square error criterion) to a desired OTF. By combining several OTF design goal requirements, each represents a different plane along the beam propagation direction, an imaging system with an increased depth of focus is obtained. Because a phase only filter is used, high energetic efficiency is achieved.     

Stress intensity factors for fatigue cracking of round bars

The stress intensity factor for a single edge crack of either straight or circular front in a round bar has been determined using both the degenerated quarter-point isoparametric finite element and experimental fatigue crack growth data, and compared with values found by earlier investigators.The results of this study confirm that the stress intensity factors for straight edged surface cracks are lower in round bars than in square bars and a comparison of finite element and experimental results indicates that the effective stress intensity factor at the centre of the fatigue crack front in a round bar is 17% greater than its theoretical value.A correction function is proposed to account for the effect on the stress intensity factor of the circular boundary of a round bar.