steam turbine control valve and actuation system modeling for dynamics analysis

Abstract The paper describes a study conducted on Steam Turbine control valve and actuation systems, which rule the machine final power production and rotational speed. A dynamic model developed in the Matlab/Simulink environment is proposed to support the analysis of the operational stability of the hydro-mechanical system as well as the failure modes that it may face during operation. The model was validated through specific field tests conducted on the actuation system at a cogeneration plant in Nuovo Pignone, Florence. The proposed work also underlines the requirements that new actuation technologies should fulfil in order to meet control valve system performance criteria

analysis of a simplified steam turbine governor model for power system stability studies

Abstract The present study describes an analysis performed on a simplified Steam Turbine governor model, which is useful for pre-tuning the machine regulation system. A dynamic model has been implemented in two different simulation tools, namely DigSILENT PowerFactory and Matlab/Simulink, to the aim of verifying the suitability of the latter one for power system stability studies. The proposed work paves the way to the wide range of possibilities connected to the integration of the machine governor model with other simulation blocks of a Combined Cycle Plant, by enabling the opportunity for pre-commissioning of the regulation system together with the analysis of the fulfillment of grid code regulations

Screening of a molecular marker for association to maturity date in peach fruit

Maturity date (MD) represents a key trait in peach given the relatively short shelf-life of peach, and the selection of cultivars with varying MD to cover and possibly extend the marketing season constitutes a key target for varietal innovation. A number of studies have identified different QTLs associated to this trait, mainly in the Linkage Groups (LG) 2, 4 and 6; and in particular, a region within LG4 was ascertained as strongly associated with harvesting time in different segregating populations. The evaluation of the association of such diagnostic markers in a wider germplasm collection would provide the breeder interesting information in selecting the best candidate for the desired ripening period and in the early identification and selection of progenies carrying the wanted trait in their breeding programs. We thus performed a comparative study using a candidate marker mapping in LG4 in order to assess its predictive power in a pool of peach and nectarine cultivars inclusive of traditional and modern germplasm to ease the early identification and selection of desired ripening genotypes in breeding programs

Validazione di un marcatore molecolare associato all’epoca di maturazione in pesco.

Nel pesco l\u2019epoca di maturazione \ue8 un target importante per l\u2019innovazione varietale. \uc8 un carattere quantitativo, cio\ue8 determinato dalla somma dell\u2019azione di pi\uf9 geni. Le regioni di DNA associate ad un particolare carattere quantitativo vengono definite QTL (Quantitative Trait Loci). Finora sono stati individuati alcuni QTL in diversi cromosomi (2, 6 e soprattutto 4). Studi recenti hanno individuato proprio all\u2019interno del cromosoma 4 un gene fortemente associato all\u2019epoca di maturazione negli individui di due progenie ottenute dall\u2019incrocio di variet\ue0 assai distanti fra loro. Grazie a tale associazione \ue8 stato trovato un marcatore molecolare (\u201cmarker\u201d) in grado di discriminare, con buona approssimazione, gli individui a maturazione precoce da quelli a maturazione tardiva. La disponibilit\ue0 di questo marcatore consentirebbe ai breeder di sviluppare nuove cultivar che maturano nel periodo desiderato e sarebbe quindi potenzialmente in grado di servire per una selezione mirata all\u2019epoca di maturazione. Per valutare il marcatore \ue8 stata fatta una verifica su un gruppo di 140 variet\ue0 di pesche e nettarine della collezione di pesco del Crea di Forl\uec, comprendenti variet\ue0 tradizionali e moderne a maturazione molto differenziata, nell\u2019arco di tre mesi