A Comparative Study of Control Strategies for Performance Optimisation of Brushless Doubly- Fed Reluctance Machines

The brushless doubly-fed machine (BDFM) allows the use of a partially rated inverter and represents an attractive cost-effective candidate for variable speed applications with limited speed ranges. In its induction machine form (BDFIM), the BDFM has significant rotor losses and poor efficiency due to the cage rotor design which makes the machine dynamic models heavily parameter dependent and the resulting controller configuration complicated and difficult to implement. A reluctance version of the BDFM, the brushless doubly-fed reluctance machine (BDFRM), ideally has no rotor losses, and therefore offers the prospect for higher efficiency and simpler control compared to the BDFIM. A detailed study of this interesting and emerging machine is very important to gain a thorough understanding of its unusual operation, control aspects and compromises between optimal performance and the size of the inverter and the machine. This paper will attempt to address these issues specifically concentrating on developing conditions for various control properties of the machine such as maximum power factor, maximum torque per inverter ampere and minimum copper losses, as well as analysing the associated trade-offs

Inheritance of flower type in some grape varieties (Vitis vinifera L.)

This paper presents the results and genetical analysis of crossing grape varieties Vitis vinifera L. with regard to the inheritance of flower type. From the results obtained, following conclusions could be drawn:The flower type (hermaphrodite and female) in grape varieties Vitis vinifera L. is controlled by two allels. The genetic factor for female flower is designated by sr and the factor for hermaphroditism by Sh. Factor Sf is recessive to Sh.Varieties with hermap hrodite flower type are either homozygous (Sh Sh) or heterozygous (Sh Sf) for hermaphroditism. Out of 20 tested varieUes with hermaphrodite flowers, 14 were heterozygous and 6 homozygous. The following varieties are homozygous: Datier, Smederevka, Queen of the Vineyards, Volovsko Oko, Traminer Red and Zilavka. Heterozygous varieties are: Muscat Hamburg, Chasselas Buvie, Pearl of Csaba, Chasselas White, Italia, Italian Riesling, Merlo, Beli Medenac, Bagrina, Semillon, Pinot Noir, Prokupac, Šljiva, Muscat Otonel.Varieties with functionally female flowers are probably homozygous, i. e. Sf Sf. These are: Čaus and Crveni Drenak. In all combinations of crossings, seedlings having homogametic flower type were in deficit.Considering the improvement of grape varieties it is suggested to use hermaphrodite varieties of t he genetic constitution Sh Sh

A new sensorless speed control scheme for doubly-fed reluctance generators

This paper presents the development and experimental validation of a novel angular velocity observer-based field-oriented control algorithm for a promising low-cost brushless doubly fed reluctance generator (BDFRG) in wind power applications. The BDFRG has been receiving increasing attention because of the use of partially rated power electronics, the high reliability of brushless design, and competitive performance to its popular slip-ring counterpart, the doubly fed induction generator. The controller viability has been demonstrated on a BDFRG laboratory test facility for emulation of variable speed and loading conditions of wind turbines or pump drives

Better Pricing Strategies for ATM?

Objectives of this paper are: briefly examine solutions applied in other network industries and based on that, set the policy and pricing context for development of market-based mechanisms for strategic air traffic re-distribution to avoid congestion, which is a main goal of SATURN project. Further, focus on current and possible future ATM pricing policy goals, by summarising current practice in Europe and introducing two possible future scenarios developed within the project. The implementation plan is outlined, discussing both the modelling challenges and the parallel consultation and validation processes. We conclude with a short look ahead

Analysis of whole genome expression in order to indentify the key genes and microRNAs for the occurence of congenital anomalies of the kidney and urinary tract in humans

Urođene anomalije bubrega i urinarnog trakta (engl. Congenital Anomalies of the Kidney and Urinary Tract – CAKUT) su razlog nastanka čak polovine slučajeva terminalne bubrežne insuficijencije ali patofiziološka osnova ove bolesti još uvek nije poznata u potpunosti pa je samim tim otežana prevencija i terapija. U ovoj studiji je, upoređivanjem ekspresije celokupnog genoma u tkivu uretera pacijenata sa CAKUT-om i zdravih kontrola, identifikovano 78 diferencijalno eksprimiranih gena. Bioinformatičkom analizom je po prvi put zaključeno da postoji visok nivo kompleksnosti bioloških procesa i molekularnih puteva u tkivu čoveka koji su u CAKUT-u diferencijalno regulisani i čije važne interakcije se mogu predstaviti sa sedam molekularnih mreža, od kojih četiri sadrže gene sa funkcijama koje se direktno mogu asocirati sa CAKUT-om. Eksperimentalnom validacijom ključnih mreža qRT-PCR metodom utvrđen je povišen nivo iRNK za gene LCN2 (7,6 puta), PROM1 (8 puta) i SOSTDC1 (5,6 puta) i snižen nivo iRNK za gene RASD1 (4,5 puta), INA (3,3 puta) i TAC3 (6,6 puta) u tkivu uretera pacijenata u poređenju sa kontrolnim tkivom, koji mogu biti molekularni markeri za CAKUT. Ove mreže su ujedno i prikaz interakcija ključnih molekula u CAKUT-u i predstavljaju temelj budućih funkcionalnih studija. Primenom metode koja povezuje podatke sa genskog ekspresionog čipa i predikcije vezujućih mesta različitih miRNK iz više predikcionih algoritama, sa unapređenom rezolucijom, identifikovane su miRNK sa potencijalno povišenom ekspresijom u CAKUT-u u odnosu na zdrave kontrole. Validacijom ključnih miRNK qRT-PCR metodom je identifikovan povišen nivo miR-144 (5,7 puta) u tkivu uretera pacijenata u odnosu na kontrole, koji može biti molekularni marker za CAKUT.Congenital anomalies of the kidney and urinary tract (CAKUT) are the cause for half of the cases with renal failure, but pathophysiological basis of this disease is not fully known. Therefore, the therapy and prevention of the disease is difficult. In this study, by comparing the whole-genome expression in the ureter tissue of patients with CAKUT and healthy controls, 78 differentially expressed genes were identified. By employing bioinformatical analysis it was concluded that there is a high level of complexity of biological processes and molecular pathways, differentialy regulated in CAKUT, whose important interactions can be represented with seven molecular networks, of which four contain genes with functions that can be directly associated with CAKUT. Experimental validation of key networks by qRT-PCR method identified elevated mRNA levels of LCN2 (7.6 fold), PROM1 (8 fold) and SOSTDC1 (5.6 fold), and decreased mRNA levels of RASD1 (4.5 fold), INA (3.3 fold) and TAC3 (6.6 fold) in the ureter tissue of the patients compared to control tissue, which may be molecular markers for CAKUT. These networks display the interactions of key molecules in CAKUT and provide the basis for future functional studies, as well. By applying the method that links microarray gene expression data and prediction of miRNA binding sites from several prediction algorithms, with enhanced resolution, miRNAs with potentialy upregulated expression in CAKUT compared to healthy controls were identified. Validation of key miRNAs by qRT-PCR method identified increased level of miR-144 (5.7 fold) in the ureter tissue of the patients compared to controls, which may be a molecular marker for CAKUT

Analysis of whole genome expression in order to indentify the key genes and microRNAs for the occurence of congenital anomalies of the kidney and urinary tract in humans

Urođene anomalije bubrega i urinarnog trakta (engl. Congenital Anomalies of the Kidney and Urinary Tract – CAKUT) su razlog nastanka čak polovine slučajeva terminalne bubrežne insuficijencije ali patofiziološka osnova ove bolesti još uvek nije poznata u potpunosti pa je samim tim otežana prevencija i terapija. U ovoj studiji je, upoređivanjem ekspresije celokupnog genoma u tkivu uretera pacijenata sa CAKUT-om i zdravih kontrola, identifikovano 78 diferencijalno eksprimiranih gena. Bioinformatičkom analizom je po prvi put zaključeno da postoji visok nivo kompleksnosti bioloških procesa i molekularnih puteva u tkivu čoveka koji su u CAKUT-u diferencijalno regulisani i čije važne interakcije se mogu predstaviti sa sedam molekularnih mreža, od kojih četiri sadrže gene sa funkcijama koje se direktno mogu asocirati sa CAKUT-om. Eksperimentalnom validacijom ključnih mreža qRT-PCR metodom utvrđen je povišen nivo iRNK za gene LCN2 (7,6 puta), PROM1 (8 puta) i SOSTDC1 (5,6 puta) i snižen nivo iRNK za gene RASD1 (4,5 puta), INA (3,3 puta) i TAC3 (6,6 puta) u tkivu uretera pacijenata u poređenju sa kontrolnim tkivom, koji mogu biti molekularni markeri za CAKUT. Ove mreže su ujedno i prikaz interakcija ključnih molekula u CAKUT-u i predstavljaju temelj budućih funkcionalnih studija. Primenom metode koja povezuje podatke sa genskog ekspresionog čipa i predikcije vezujućih mesta različitih miRNK iz više predikcionih algoritama, sa unapređenom rezolucijom, identifikovane su miRNK sa potencijalno povišenom ekspresijom u CAKUT-u u odnosu na zdrave kontrole. Validacijom ključnih miRNK qRT-PCR metodom je identifikovan povišen nivo miR-144 (5,7 puta) u tkivu uretera pacijenata u odnosu na kontrole, koji može biti molekularni marker za CAKUT.Congenital anomalies of the kidney and urinary tract (CAKUT) are the cause for half of the cases with renal failure, but pathophysiological basis of this disease is not fully known. Therefore, the therapy and prevention of the disease is difficult. In this study, by comparing the whole-genome expression in the ureter tissue of patients with CAKUT and healthy controls, 78 differentially expressed genes were identified. By employing bioinformatical analysis it was concluded that there is a high level of complexity of biological processes and molecular pathways, differentialy regulated in CAKUT, whose important interactions can be represented with seven molecular networks, of which four contain genes with functions that can be directly associated with CAKUT. Experimental validation of key networks by qRT-PCR method identified elevated mRNA levels of LCN2 (7.6 fold), PROM1 (8 fold) and SOSTDC1 (5.6 fold), and decreased mRNA levels of RASD1 (4.5 fold), INA (3.3 fold) and TAC3 (6.6 fold) in the ureter tissue of the patients compared to control tissue, which may be molecular markers for CAKUT. These networks display the interactions of key molecules in CAKUT and provide the basis for future functional studies, as well. By applying the method that links microarray gene expression data and prediction of miRNA binding sites from several prediction algorithms, with enhanced resolution, miRNAs with potentialy upregulated expression in CAKUT compared to healthy controls were identified. Validation of key miRNAs by qRT-PCR method identified increased level of miR-144 (5.7 fold) in the ureter tissue of the patients compared to controls, which may be a molecular marker for CAKUT

Absorbing-state phase transitions with extremal dynamics

Extremal dynamics represents a path to self-organized criticality in which the order parameter is tuned to a value of zero. The order parameter is associated with a phase transition to an absorbing state. Given a process that exhibits a phase transition to an absorbing state, we define an ``extremal absorbing" process, providing the link to the associated extremal (nonabsorbing) process. Stationary properties of the latter correspond to those at the absorbing-state phase transition in the former. Studying the absorbing version of an extremal dynamics model allows to determine certain critical exponents that are not otherwise accessible. In the case of the Bak-Sneppen (BS) model, the absorbing version is closely related to the "$f$-avalanche" introduced by Paczuski, Maslov and Bak [Phys. Rev. E {\bf 53}, 414 (1996)], or, in spreading simulations to the "BS branching process" also studied by these authors. The corresponding nonextremal process belongs to the directed percolation universality class. We revisit the absorbing BS model, obtaining refined estimates for the threshold and critical exponents in one dimension. We also study an extremal version of the usual contact process, using mean-field theory and simulation. The extremal condition slows the spread of activity and modifies the critical behavior radically, defining an ``extremal directed percolation" universality class of absorbing-state phase transitions. Asymmetric updating is a relevant perturbation for this class, even though it is irrelevant for the corresponding nonextremal class.Comment: 24 pages, 11 figure

Efekat organske proizvodnje mleka na neke parametre kvaliteta mleka

In recent years there is growing interest of consumers for the consumption of organic milk, because of its favorable content of fatty acids that has a positive effect on human health. The aim of this study was to examine the content of fatty acids, vitamins A, C and α - tocopherol in milk which was obtained in different production systems, organic and conventional. The samples of conventional and organic milk were collected from farms located in Vojvodina, throughout all seasons. The prepared samples were analyzed using gas chromatography with mass spectrometry and high - performance liquid chromatography. The results proved that the milk produced in accordance with the principles of organic production had a higher content of polyunsaturated and omega-3 fatty acids compared with conventional milk (p lt 0.01) during the whole examination period, while the greatest differences were perceived in the pasture season. Also, organic milk had a higher content of vitamins A, C and α - tocopherol compared with the conventionally produced milk, although there was no statistically significant difference.Poslednjih godina raste interes potrošača za konzumiranje organskog mleka, zbog povoljnijeg sadržaja masnih kiselina koje imaju pozitivan efekat na zdravlje ljudi. Cilj ovog rada je bio da se ispita sadržaj masnih kiselina, vitamina A, C i α-tokoferola u mleku koje je dobijeno u različitim sistemima proizvodnje, organskom i konvencionalnom. Uzorci konvencionalnog i organskog mleka sakupljani su na farmama u Vojvodini tokom čitave godine. Analiza uzoraka je vršena primenom metoda gasne hromatografije i tečne hromatografije. Rezultati su pokazali da je mleko proizvedeno po principima organske proizvodnje tokom celog perioda praćenja imalo veći sadržaj polinezasićenih i omega-3 masnih kiselina u odnosu na konvencionalno mleko (p lt 0,01), s tim što su najveće razlike bile u sezoni paše. Sadržaj vitamina A, C i α -tokoferola bio je veći u organskom mleku od sadržaja u mleku iz konvencionalne proizvodnje, mada nije utvrđena statistička značajnost ovih razlika