782 research outputs found

    A new coupling solution for G3-PLC employment in MV smart grids

    Get PDF
    This paper proposes a new coupling solution for transmitting narrowband multicarrier power line communication (PLC) signals over medium voltage (MV) power lines. The proposed system is based on an innovative PLC coupling principle, patented by the authors, which exploits the capacitive divider embedded in voltage detecting systems (VDS) already installed inside the MV switchboard. Thus, no dedicated couplers have to be installed and no switchboard modifications or energy interruptions are needed. This allows a significant cost reduction of MV PLC implementation. A first prototype of the proposed coupling system was presented in previous papers: it had a 15 kHz bandwidth useful to couple single carrier PSK modulated PLC signals with a center frequency from 50–200 kHz. In this paper, a new prototype is developed with a larger bandwidth, up to 164 kHz, thus allowing to couple multicarrier G3-PLC signals using orthogonal frequency division multiplexing (OFDM) digital modulation. This modulation ensures a more robust communication even in harsh power line channels. In the paper, the new coupling system design is described in detail. A new procedure is presented for tuning the coupling system parameters at first installation in a generic MV switchboard. Finally, laboratory and in-field experimental test results are reported and discussed. The coupling performances are evaluated measuring the throughput and success rate in the case of both 18 and 36 subcarriers, in one of the different tone masks standardized for the FCC-above CENELEC band (that is, from 154.6875–487.5 kHz). The experimental results show an efficient behavior of the proposed coupler allowing a two-way communication of G3-PLC OFDM signals on MV networks

    Financial Services Modernization: A Cure for Problem Banks?

    Get PDF
    On February 5, 1991, after consulting federal financial regulatory agencies and other interested governmental parties, the Department of the Treasury transmitted to Congress its report: Modernizing the Financial System: Recommendations for Safer, More Competitive Banks. The Treasury Report concludes that four major problems confront the U.S. banking system: (1) reduced bank competitiveness and financial strength, caused by outdated legal restrictions that prevent banks from responding to changing financial markets and technology; (2) the overextension of deposit insurance, resulting in excessive exposure for taxpayers and weakened market discipline for banks; (3) a fragmented regulatory system that has created duplicative rules and has often failed to produce decisive remedial action; and (4) an undercapitalized deposit insurance fund. To address these problems, the Treasury Report recommends four fundamental legislative reforms: (1) to increase bank competitiveness, Congress should authorize nation-wide banking, new financial activities for banks, and commercial ownership of banks; (2) to reduce taxpayer exposure and increase market discipline, Congress should reduce the scope of deposit insurance, require a link between regulatory supervision and capital strength, and require risk-based insurance premiums for deposit insurance; (3) to reduce duplicative rules and produce decisive remedial action, Congress should streamline the federal regulatory system; and (4) to recapitalize the Bank Insurance Fund, Congress should adopt a funding plan based on contributions from the banking industry, rather than from the Treasury and the taxpayers. After a very basic historical review of past attempts to reform the banking industry, this Article focuses on the less publicized portions of the Treasury recommendations in an attempt to identify some of the issues that would remain unsettled, even if the proposals are enacted into law

    Galactosylsphingamides : new α-GalCer analogues to probe the F’-pocket of CD1d

    Get PDF
    Invariant Natural Killer T-cells (iNKT-cells) are an attractive target for immune response modulation, as upon CD1d-mediated stimulation with KRN7000, a synthetic alpha-galactosylceramide, they produce a vast amount of cytokines. Here we present a synthesis that allows swift modification of the phytosphingosine side chain by amidation of an advanced methyl ester precursor. The resulting KRN7000 derivatives, termed alpha-galactosylsphingamides, were evaluated for their capacity to stimulate iNKT-cells. While introduction of the amide-motif in the phytosphingosine chain is tolerated for CD1d binding and TCR recognition, the studied alpha-galactosylsphingamides showed compromised antigenic properties

    Brown rotting fungus closely related to Pseudomerulius curtisii (Boletales) recorded for the first time in South America.

    Get PDF
    In the region of Santa Maria, Southern Brazil, we have analyzed morphologically and molecularly some interesting brown-rotting mushroom specimens closely related to Pseudomerulius curtisii. Except for minor differences in morphology and ITS sequence similarity, collections have corresponded to P. curtisii by basidiospore size and shape, the kind of hyphal system, the macromorphology, the slightly unpleasant pungent spicy smell turning stronger upon drying and, particularly, by the highly supported and closely related clade after phylogenetic analysis. Perhaps due the rarity in nature, morphological data are not abundant in literature and appears to be somewhat incomplete to discordant for the species, so we provide a more detailed description and illustrations from collected specimens

    Characterization of DC series arc faults in PV systems based on current low frequency spectral analysis

    Get PDF
    This work presents an experimental study focused on the characterization of series arc faults in direct current (DC) photovoltaic (PV) systems. The aim of the study is to identify some relevant characteristics of arcing current, which can be obtained by means of low frequency spectral analysis of current signal. On field tests have been carried out on a real PV system, in accordance with some tests requirements of UL 1699B Standard for protection devices against PV DC arc faults. Arcing and non-arcing current signals are acquired and compared and the behavior of a set of indicators proposed by authors is analyzed. Different measurement equipment have been used, in order to study the impact of both measurement transducers and data acquisition systems on proposed indicators effectiveness. Presented results show that the considered indicators are suitable for detecting the arc presence even with commercial devices normally used for smart metering applications

    Does structured counselling influence combined hormonal contraceptive choice?

    Get PDF
    Objective To assess the effect of structured counselling on women's contraceptive decisions and to evaluate gynaecologists' perceptions of comprehensive contraceptive counselling. Methods Belgian women (18-40 years old) who were considering using a combined hormonal contraceptive (CHC) were counselled by their gynaecologists about available CHCs (combined oral contraceptive [COC], transdermal patch, vaginal ring), using a comprehensive leaflet. Patients and gynaecologists completed questionnaires that gathered information on the woman's pre- and post-counselling contraceptive choice, her perceptions, and the reasons behind her post-counselling decision. Results The gynaecologists (N = 121) enrolled 1801 eligible women. Nearly all women (94%) were able to choose a method after counselling (53%, 5%, and 27% chose the COC, the patch, and the ring, respectively). Counselling made many women (39%) select a different method: patch use increased from 3% to 5% (p < 0.0001); ring use tripled (from 9% to 27%, p < 0.0001). Women who were undecided before counselling most often opted for the method their gynaecologist recommended, irrespective of counselling. Conclusion Counselling allows most women to select a contraceptive method; a sizeable proportion of them decide on a method different from the one they initially had in mind. Gynaecologists' preferences influenced the contraceptive choices of women who were initially undecided regarding the method to use

    Incremental heuristic approach for meter placement in radial distribution systems

    Get PDF
    The evolution of modern power distribution systems into smart grids requires the development of dedicated state estimation (SE) algorithms for real-time identification of the overall system state variables. This paper proposes a strategy to evaluate the minimum number and best position of power injection meters in radial distribution systems for SE purposes. Measurement points are identified with the aim of reducing uncertainty in branch power flow estimations. An incremental heuristic meter placement (IHMP) approach is proposed to select the locations and total number of power measurements. The meter placement procedure was implemented for a backward/forward load flow algorithm proposed by the authors, which allows the evaluation of medium-voltage power flows starting from low-voltage load measurements. This allows the reduction of the overall costs of measurement equipment and setup. The IHMP method was tested in the real 25-bus medium-voltage (MV) radial distribution network of the Island of Ustica (Mediterranean Sea). The proposed method is useful both for finding the best measurement configuration in a new distribution network and also for implementing an incremental enhancement of an existing measurement configuration, reaching a good tradeoff between instrumentation costs and measurement uncertainty

    A Line Impedance Calculator Based on a G3 PLC Modem Platform

    Get PDF
    Power line communication (PLC) is one of the most today used technologies for both automatic meter reading and many other smart grid applications. In this framework, a characterization of the electrical network in the PLC frequency range is needed in terms of impedance measurement and received signal level. This can allow choosing the most suitable and less noisy frequency ranges for PLC transmission. Usually, these characterization measurements are performed with dedicated instrumentation and in the absence of mains voltage. This article wants to propose an alternative solution, which allows these kinds of measurements to be performed using electronic boards currently used as on-field applications, such as smart meters. To this aim, an innovative measurement tool is proposed, which does not need a specific characterization signal to be injected because it uses the preamble of a generic PLC transmission. Moreover, the impedance calculation is performed using an FFT analysis, which does not require high computational capabilities. These features allowed the proposed tool to be implemented using a G3-PLC transceiver, embedded in many commercial smart meters, and low-cost additional hardware. This article shows how the proposed system correctly measures the PLC impedance on CENELEC A, B, and FCC frequency ranges

    Li-ion battery modeling and state of charge estimation method including the hysteresis effect

    Get PDF
    In this paper, a new approach to modeling the hysteresis phenomenon of the open circuit voltage (OCV) of lithium-ion batteries and estimating the battery state of charge (SoC) is presented. A characterization procedure is proposed to identify the battery model parameters, in particular, those related to the hysteresis phenomenon and the transition between charging and discharging conditions. A linearization method is used to obtain a suitable trade-off between the model accuracy and a low computational cost, in order to allow the implementation of SoC estimation on common hardware platforms. The proposed characterization procedure and the model effectiveness for SoC estimation are experimentally verified using a real grid-connected storage system. A mixed algorithm is adopted for SoC estimation, which takes into account both the traditional Coulomb counting method and the developed model. The experimental comparison with the traditional approach and the obtained results show the feasibility of the proposed approach for accurate SoC estimation, even in the presence of low-accuracy measurement transducers

    The first next-generation sequencing approach to the mitochondrial phylogeny of African monogenean parasites (Platyhelminthes: Gyrodactylidae and Dactylogyridae)

    Get PDF
    Abstract Background Monogenean flatworms are the main ectoparasites of fishes. Representatives of the species-rich families Gyrodactylidae and Dactylogyridae, especially those infecting cichlid fishes and clariid catfishes, are important parasites in African aquaculture, even more so due to the massive anthropogenic translocation of their hosts worldwide. Several questions on their evolution, such as the phylogenetic position of Macrogyrodactylus and the highly speciose Gyrodactylus, remain unresolved with available molecular markers. Also, diagnostics and population-level research would benefit from the development of higher-resolution genetic markers. We aim to offer genetic resources for work on African monogeneans by providing mitogenomic data of four species (two belonging to Gyrodactylidae, two to Dactylogyridae), and analysing their gene sequences and gene order from a phylogenetic perspective. Results Using Illumina technology, the first four mitochondrial genomes of African monogeneans were assembled and annotated for the cichlid parasites Gyrodactylus nyanzae, Cichlidogyrus halli, Cichlidogyrus mbirizei (near-complete mitogenome) and the catfish parasite Macrogyrodactylus karibae (near-complete mitogenome). Complete nuclear ribosomal operons were also retrieved, as molecular vouchers. The start codon TTG is new for Gyrodactylus and for Dactylogyridae, as is the incomplete stop codon TA for Dactylogyridae. Especially the nad2 gene is promising for primer development. Gene order was identical for protein-coding genes and differed between the African representatives of these families only in a tRNA gene transposition. A mitochondrial phylogeny based on an alignment of nearly 12,500 bp including 12 protein-coding and two ribosomal RNA genes confirms that the Neotropical oviparous Aglaiogyrodactylus forficulatus takes a sister group position with respect to the other gyrodactylids, instead of the supposedly ‘primitive’ African Macrogyrodactylus. Inclusion of the African Gyrodactylus nyanzae confirms the paraphyly of Gyrodactylus. The position of the African dactylogyrid Cichlidogyrus is unresolved, although gene order suggests it is closely related to marine ancyrocephalines. Conclusions The amount of mitogenomic data available for gyrodactylids and dactylogyrids is increased by roughly one-third. Our study underscores the potential of mitochondrial genes and gene order in flatworm phylogenetics, and of next-generation sequencing for marker development for these non-model helminths for which few primers are available
    corecore