Performance of distance relay mho elements on MOV-protectedseries-compensated transmission lines

It is shown that the applicability of memory-polarized distance relay mho elements to the protection of MOV (metal oxide varistor) protected series-compensated lines is dependent on the system configuration, line loading, the location of the potential source, and the magnitude of memory polarization. For a configuration with compensation at one end of a line, the results indicate certain advantages in using the potential from the line side of the capacitor, and the use of a relatively large magnitude of memory polarization. The presence of a conducting MOV enhances the performance of the mho element both in terms of security on reverse faults and dependability on forward faults. The results obtained pertain to the proposed application in the Ontario Hydro system of a relatively large amount of compensation at one terminal in each circuit of a double-circuit line     

Microchip atmospheric pressure chemical ionization source for mass spectrometry

A novel microchip heated nebulizer for atmospheric pressure chemical ionization mass spectrometry is presented. Anisotropic wet etching is used to fabricate the flow channels, inlet, and nozzle on a silicon wafer. An integrated heater of aluminum is sputtered on a glass wafer. The two wafers are jointed by anodic bonding, creating a two-dimensional version of an APCI source with a sample channel in the middle and gas channels symmetrically on both sides. The ionization is initiated with an external corona-discharge needle positioned 2 mm in front of the microchip heated nebulizer. The microchip APCI source provides flow rates down to 50 nL/min, stable long-term analysis with chip lifetime of weeks, good quantitative repeatability (RSD < 10%) and linearity (r(2) > 0.995) with linear dynamic rage of at least 4 orders of magnitude, and cost-efficient manufacturing. The limit of detection (LOD) for acridine measured with microchip APCI at flow rate of 6.2 muL/min was 5 nM, corresponding to a mass flow of 0.52 fmol/s. The LOD with commercial macro-APCI at a flow rate of 1 mL/min for acridine was the same, 5 nM, corresponding to a significantly worse mass flow sensitivity (83 fmol/s) than measured with microchip APCI. The advantages of microchip APCI makes it a very attractive new microfluidic detector.     

Atmospheric circulation patterns influencing variations in organic carbon fluxes in the River Oulujoki,Finland

Atmospheric circulation generally influences regional climate variability and thereby controls catchment hydrology and consequently transport of elements in natural riverine systems. This study examined dependencies between total organic carbon (TOC) variability in the River Oulujoki (Finland) during 1963–2011 and prominent atmospheric circulation patterns (ACPs), which manifest natural climatic conditions over Finland and control hydrological processes in the river catchment. North Atlantic Oscillation, Scandinavia, East Atlantic and East Atlantic/West Russia patterns were statistically significant ACPs affecting variations in TOC export at River Oulujoki lower basin area. In the River Oulujoki, TOC export was largely controlled by changes in TOC fluxes generated from tributaries of river and near areas to its main channel. Besides, runoff from Lake Oulujärvi slightly influenced TOC export variability in the River Oulujoki. Understanding such responses of TOC fluxes to ACPs is a useful tool for sustainable water resources planning and management on regional and local scales.     

Adrenomedullin gene expression in the rat heart is stimulated by acute pressure overload: blunted effect in experimental hypertension

The levels of adrenomedullin (ADM), a newly discovered vasodilating and natriuretic peptide, are elevated in plasma and ventricular myocardium in human congestive heart failure suggesting that cardiac synthesis may contribute to the plasma concentrations of ADM. To examine the time course of induction and mechanisms regulating cardiac ADM gene expression, we determined the effect of acute and short-term cardiac overload on ventricular ADM mRNA and immunoreactive ADM (ir-ADM) levels in conscious rats. Acute pressure overload was produced by infusion of arginine8-vasopressin (AVP, 0.05 microg/kg/min, i.v.) for 2 h into 12-week-old hypertensive TGR(mREN-2)27 rats and normotensive Sprague-Dawley (SD) rats. Hypertension and marked left ventricular hypertrophy were associated with 2.2-times higher ir-ADM levels in the left ventricular epicardial layer (178 +/- 36 vs. 81 +/- 23 fmol/g, P<0.05) and 2.6-times higher ir-ADM levels in the left ventricular endocardial layer (213 +/- 23 vs. 83 +/- 22 fmol/g, P<0.01). The infusion of AVP for 2 h in normotensive rats produced rapid increases in the levels of left ventricular ADM mRNA (epicardial layer: 1.6-fold, P<0.05) and ir-ADM (endocardial layer: from 83 +/- 22 to 140 +/- 12 fmol/g, P<0.05), whereas ventricular ADM mRNA and ir-ADM levels did not change significantly in hypertensive rats. Short-term cardiac overload, induced by administration of angiotensin II (33.3 microg/kg/h, s.c., osmotic minipumps) for two weeks in normotensive SD rats resulted in left ventricular hypertrophy (3.05 +/- 0.17 vs. 2.75 +/- 0.3 mg/g, P<0.05) and a 1.5-fold increase (P<0.05) in ventricular ADM mRNA levels. In conclusion, the present results show that pressure overload acutely stimulated ventricular ADM gene expression in conscious normotensive rats suggesting a potential beneficial role for endogenous ADM production in the heart against cardiac overload. Since pressure overload-induced increase in ADM synthesis was attenuated in hypertensive rats, alterations in the ADM system may contribute to the pathogenesis of hypertension in the TGR(mREN-2)27 rat.     

A Ser315Thr substitution in KatG is predominant in genetically heterogeneous multidrug-resistant Mycobacterium tuberculosis isolates originating from the St. Petersburg area in Russia

Parts of katG and rpoB from 27 Russian Mycobacterium tuberculosis isolates were sequenced to detect mutations causing resistance to isoniazid (INH) and rifampin (RMP), respectively. All 24 INH-resistant isolates had a mutated katG, and 22 of them (91.7%) carried a mutation coding for a Ser315Thr shift. An rpoB mutation was noted for each of the 21 RMP-resistant isolates, with Ser531Leu being the most prevalent change encoded. Only two isolates had identical IS6110 fingerprints.     

Infrastructuring for Cultural Commons

In this paper we reflect on our involvement in the design and development of two information systems: Fusion and EUscreen. Both are infrastructural initiatives aimed at contributing, from different angles, to wider public access to and appropriation of the European digital cultural heritage. Our analysis is founded on the notions of an installed base and gateway in information infrastructure development. We situate our co-design activities and infrastructuring strategies in relation to a broader interest in advocating not only the preservation of and access to digital cultural heritage, but, more importantly, enabling collaboration, to support the emerging practices of diverse user groups, and to contribute to cultural commons.     

Quadrature ���� Modulators for Cognitive Radio��I/Q Imbalance Analysis and Complex Multiband Principle

This article discusses the applicability of quadrature ΣΔ modulator (QΣΔM) based analog-to-digital (A/D) conversion in cognitive radio (CR) receivers. First, unavoidable in-phase/quadrature (I/Q) mismatch effects, limiting the dynamic range, are analyzed in closed-form in the case of a first-order modulator. In addition, using the derived analytical converter model, it is shown that notching the signal transfer function (STF) of the modulator at the mirror frequencies of the desired signals will effectively cancel the I/Q imbalance induced mirror-frequency interference in case of the modulator feedback mismatch. In practice, such STF design is easy to implement within the existing converter circuitry, as will be demonstrated in this article. The latter part of the article proposes a novel complex multiband QΣΔM scheme, particularly aimed for the CR receivers. This multiband scheme allows parallel reception of scattered frequency chunks in the CR context and is stemming from the additional degrees of freedom in noise transfer function (NTF) design, provided by the QΣΔM principle. Here multiple noise shaping notches on distinct frequencies are effectively realized through proper design of complex NTF. The modulator structure also allows flexible reconfigurability of the notches with straightforward parameterization of the modulator transfer functions. When combined with the above mirror-frequency rejecting STF design, the concept is demonstrated and proved effective and robust against I/Q imbalances using practical radio signal simulations in realistic received signal conditions.     

Effects of fiber blending and diamines on wheat gluten materials reinforced with hemp fiber

Wheat gluten (WG) is a promising base material for production of “green” plastics, although reinforcement is needed in more demanding applications. Hemp fiber is a promising reinforcement source but difficulties exist in obtaining desired properties with a WG-based matrix. This study aimed at improving fiber dispersion and fiber–matrix interactions using a high speed blender and a diamine as a cross-linker. Samples were manufactured using compression molding, two types of blenders and addition of diamine. Mechanical properties were assessed with tensile testing. Tensile-fractured surfaces were examined with scanning electron microscopy (SEM). Protein polymerization and fiber–protein matrix interactions were examined using high performance liquid chromatography (HPLC) and confocal laser scanning microscopy (CLSM). The results showed that a higher-speed grinding yielded a more even distribution of fibers and a more polymerized protein structure compared to a lower-speed grinding. However, these improvements did not result in increased strength, stiffness, and extensibility for the higher-speed grinding. The strength was increased when the grinding was combined with addition of a diamine (Jeffamine^? EDR-176). HPLC, SEM, and CLSM, indicated that diamine added samples showed a more “plastic” appearance together with a stiffer and stronger structure with less cracking compared to samples without diamine. The use of the diamine also led to an increased polymerization of the proteins, although no effect on the fiber–protein matrix interactions was observed using microscopical techniques. Thus, for future successful use of hemp fibers to reinforce gluten materials, an appropriate method to increase the fiber–protein matrix interaction is needed.     

The potential of enzymatic peeling of vegetables

Epiderms of potatoes (Solanum tuberosum cv Asterix), carrots (Daucus carota L), Swedish turnips (Brassica napus L) and onions (Allium cepa L) were isolated and their structure was studied by bright‐field and epifluorescence microscopy as well as by chemical analyses. The suitability of commercial cellulase and pectinase preparations for the hydrolysis of isolated peels and whole vegetables was investigated. The enzymatic pretreatment significantly enhanced the degradation of peels of carrots and onions, whereas the hydrolysis of potato and Swedish turnip peels was very limited owing to the high cutin/suberin content on the vegetable surface. Copyright © 2003 Society of Chemical Industry     

Predicting the bending properties of air dried and modified <Emphasis Type="Italic">Populus tremula</Emphasis> L. wood using combined air-coupled ultrasound and electrical impedance spectroscopy

Air-coupled ultrasound and electrical impedance spectroscopy are non-destructive measurement methods, which can be used, for example for quality assessment of sawn timber. Both methods may be used in through-transmission and one-sided reflection mode to measure internal properties and detect defects in wood materials. The ultrasound method is based on mechanical waves and is mainly affected by the mechanical properties of wood. Density affects both methods, and the electrical impedance method is especially affected by moisture content and the chemical properties of wood. In this study, the relations between the methods and the bending properties of air dried and modified aspen (Populus tremula L.) specimens were examined. The modification method was a combination of compression and thermal modification. According to the study, electrical impedance spectroscopy combined with air-coupled ultrasound measured across the grain is a potential non-destructive technique for the strength estimation of aspen wood.