Widespread infection of lake whitefish Coregonus clupeaformis with the swimbladder nematode Cystidicola farionis in northern lakes Michigan and Huron

We estimated the prevalence, intensity, and abundance of swimbladder nematode infection in 1281 lake whitefish (Coregonus clupeaformis) collected from four sites in northern lakes Huron (Cheboygan and DeTour Village) and Michigan (Big Bay de Noc and Naubinway) from fall 2003 through summer 2006. Morphological examination of nematode egg, larval, and mature stages through light and scanning electron microscopy revealed characteristics consistent with that of Cystidicola farionis Fischer 1798. Total C. farionis prevalence was 26.94%, while the mean intensity and abundance of infection was 26.72 and 7.21 nematodes/fish, respectively. Although we detected C. farionis in all four stocks that were examined, Lake Huron stocks generally had higher prevalence, intensity, and abundance of infection than Lake Michigan stocks. A distinct seasonal fluctuation in prevalence, abundance, and intensity of C. farionis was observed, which does not coincide with reported C. farionis development in other fish species. Lake whitefish that were heavily infected with C. farionis were found to have thickened swimbladder walls with deteriorated mucosa lining, which could affect swimbladder function. Whether C. farionis infection may be negatively impacting lake whitefish stocks in the Great Lakes is unclear; continued monitoring of C. farionis infection should be conducted to measure responses of lake whitefish stocks to infection levels.     

The Effects of Surface Waviness and Length on Electrokinetic Transport in Wavy Capillary

An electrokinetic model for a wavy capillary has been developed. Poisson‐Nernst‐Planck and Navier‐Stokes equations constitute the model that governs fluid and ionic fluxes and electric potential distribution inside the capillary. In the present paper, a finite wavy cylindrical capillary with a large reservoir at both capillary ends is analyzed using finite element method. The model is used primarily to examine the influence of capillary surface waviness on the electrokinetic transport behaviours. Different frequencies and amplitudes of the wavy surface are considered to investigate the influence of surface waviness on electrokinetic transport. Fluctuations in potential and ionic concentration distribution increase with the increase in either amplitude or frequency of the capillary surface waviness. However, for higher frequencies the fluctuation diminishes for all surface waviness amplitudes. It is observed that for any irregularity in the capillary surface results in higher salt rejection. Salt rejection is found to be dependent on capillary axial length as well as flow velocity. A critical Peclet number, beyond which salt rejection attains a constant steady value, dictates maximum salt rejection.     

Dielectric and Superconducting Photonic Crystals

We present the transmittance of two types of one-dimensional periodic structures. The first type of structure consists of alternating layers of a dielectric material. The second type of structure consists of alternating layers of a dielectric material and a superconductor whose dielectric properties are described by the two-fluid model. The variance of the intensity and the bandwidth of the transmittance are strongly dependent on the thicknesses, temperature, and frequencies. We have compared the transmittance spectra and present some details about the two types of structure. In the first type, we will make a comparison between the optical properties of the high temperature superconducting photonic crystal (HTScPC) by using the YBa₂Cu₃O₇ as a superconductor layer with SrTiO₃ as a dielectric layer. The second type consists of the dielectric photonic crystals (DPCs) and Al₂O₃ or MgO with SrTiO₃ within the ultra-violet region. The comparison obtained according to the difference of the thickness of SrTiO₃ and the variance of the number of periods. The common result is changed in the number of PBGs within the UV range.     

Superconductor-Semiconductor Metamaterial Photonic Crystals

We constructed theoretically one-dimensional photonic crystal (1DPC) by using a semiconductor metamaterial in the near-infrared range(NIR) which is composed of Al-doped Z n O(A Z O) and Z n O. The construction of this photonic crystal (PC) is based on a high-temperature superconductor material with the semiconductor metamaterial as constituent layers for this PC. The electromagnetic interactions with this periodic structure are investigated using the transfer matrix method (TMM) in the NIR range. The investigation shows that the reflectance spectra are depending on some parameters of the periodic structure such as the thicknesses of the constituent layers, temperature, and the angle of incidence.     

Photocatalytic study of some synthesized MWCNTs/TiO2 nanocomposites used in the treatment of industrial hazard materials

Multi-walled carbon nanotubes/titanium dioxide nanocomposites were successfully synthesized by Sol-Gel method using new different ratios of tetrabutyl titanate and functionalized MWCNTs as the starting precursors. The synthesized Multi-walled carbon nanotubes/different titanium dioxide percentages (MWCNTs/3, 6 and 10%TiO₂) nanocomposites were characterized using XRD, SEM and N₂ Adsorption-Desorption techniques. The optical band gap was estimated for MWCNTs and MWCNTs with different TiO₂ percentages by Kubelka-Munk equation giving 3.72, 2.92, 2.83, 2.71 eV values respectively. The synthesized nanocomposites were used as photocatalyst for decontamination of two local textile Dianix Blue and Vat Green 1 Dyes which commonly used in dyeing manufacture in local market.     

Risk-based reliability evaluation of multi-site damage in pipelines

In this paper, a probabilistic procedure is used to conduct local fracture evaluation of pipelines subjected to multiple cracking in service. Mixed-mode fracture mechanics is applied to a multiple cracking case of two non-coplanar parallel cracks in an infinite elastic solid plate under remote tension. A numerical simulation model is then used to determine the relation between the proximity of the cracks interacting tips and the conditions under which they may not coalesce. Based on these results, a Monte Carlo simulation model is then applied to establish a correlation between the existing population of cracks configuration and the reliability of pipelines affected by multi-site damage (MSD). Thus, the relation between failure probibility and pipelines serviceability is investigated. It is concluded that the maintenance strategies used to optimize safety for pipelines could be based on a probabilistic analysis that permits risk assessments associated with the pipelines operating decisions as well as the type and frequency of inspection done to ensure continued safe operation of these lines.     

Trajectory databases: Data models,uncertainty and complete query languages

Moving objects produce trajectories. We describe a data model for trajectories and trajectory samples and an efficient way of modeling uncertainty via beads for trajectory samples. We study transformations of the ambient space for which important physical properties of trajectories, such as speed, are invariant. We also determine which transformations preserve beads. We give conceptually easy first-order complete query languages and computationally complete query languages for trajectory databases, which allow to talk directly about speed and uncertainty in terms of beads. The queries expressible in these languages are invariant under speed- and bead-preserving transformations.     

Challenges in fabrication and testing of piezoelectric MEMS with a particular focus on energy harvesters

In this paper an overview of some of the challenges encountered in the fabrication and testing of MEMS-based piezoelectric devices is presented. All major steps involved in developing piezoelectric MEMS, with particular focus on energy harvesters, are examined in three main sections: Microfabrication, Packaging and Testing. Although the main focus of this paper are the challenges involved with vibration based piezoelectric energy harvesters, most of these challenges apply to other piezoelectric MEMS devices. Various techniques reported for each individual fabrication step are categorized to provide a summary of required information. This allows new researchers to estimate the overall fabrication process, available resources and equipment to prepare accordingly. In addition, challenges of each technique are pointed out explicitly with solutions from literature and our own research. These challenges are typically overlooked in results-based technical papers. Some of the technical solutions discussed were achieved in our experimental work. For other solutions found in literature, references are provided to address issues more in detail. Packaging piezoelectric energy harvesters can be especially challenging. Although a variety of packaging solutions exist for MEMS, these solutions are generic and must be adapted to fit the specific needs of the energy harvesters. This paper illustrates some packaging schemes that have been developed in our research to overcome these challenges. In addition, testing challenges and equipment requirements are discussed with sample results demonstrated. This article explores all fabrication steps, reviews literature, points out challenges and provides solutions with regard to developing piezoelectric MEMS.     

A New Approach to Cleave MEMS Devices from Silicon Substrates

Dicing of fabricated MEMS （microelectromechanical system） devices is sometimes a source of challenge, especially when devices are overhanging structures. In this work, a modified cleaving technique is developed to precisely separate fabricated devices from a silicon substrate without requiring a dicing machine. This technique is based on DRIE （deep reactive ion etching） which is regularly used to make cleaving trenches in the substrate during the releasing stage. Other similar techniques require some extra later steps or in some cases a long HF soak. To mask the etching process, a thick photoresist is used. It is shown that by applying different UV （ultraviolate） exposure and developing times for the photoresist, the DRIE process could be controlled to etch specific cleaving trenches with less depth than other patterns on the photoresist. Those cleaving trenches are used to cleave the wafer later, while the whole wafer remains as one piece until the end of the silicon etching despite some features being etched all the way through the wafer at the same time. The other steps of fabricating and releasing the devices are unaffected. The process flow is described in details and some results of applying this technique for cleaving fabricated cantilevers on a silicon substrate are presented.