Procjena varijabli stanja sustava s gorivnim člankom i uzlaznim pretvaračem metodom brzog uzorkovanja signala

Estimation of state variables of a peak current mode (PCM) controlled DC-DC boost converter supplied by a PEM fuel cell is described in this paper. Since this system is highly nonlinear and non-minimum phase, its state variables are estimated by using fast output sampling method. Estimated state variables are the converter output voltage and its first derivative, and they are suitable for model reference adaptive control or sliding mode based control techniques. The estimator has been designed in a way that it gives a good estimate of the state variables in the continuous and in the discontinuous conduction mode of the converter, and in the presence of measurement and process noise caused by converter switching-mode operation. Experimental results of estimating the state variables on a 450 W boost converter supplied by the emulator of the PEM fuel cell BCS 64-32 show good results of the estimation, regardless of the conduction mode of the converter, i.e. the operating point determined by its output current.U ovom radu obrađena je procjena varijabli stanja sustava s istomjernim uzlaznim pretvaračem u vršnom strujnom načinu upravljanja napajanim PEM gorivnim člankom. Budući da je taj sustav izrazito nelinearan te neminimalno-fazan, za procjenu njegovih varijabli stanja upotrebljena je metoda brzog uzorkovanja izlaznog signala. Procjenjene varijable stanja su izlazni napon uzlaznog pretvarača te njegova prva derivacija, te su pogodne za adaptivno upravljanje s referentnim modelom i upravljanje temeljeno na kliznim režimima. Procjenitelj je projektiran na način da daje dobru procjenu varijabli stanja u kontinuiranom i diskontinuiranom režimu rada pretvarača, te u uvjetima mjernog i procesnog šuma uzrokovanog sklopnim načinom rada pretvarača. Eksperimentalni rezultati procjene varijabli stanja na uzlaznom pretvaraču snage 450 W napajanim emulatorom gorivnog članka BCS 64-32 pokazuju dobre rezultate procjene, neovisno o režimu rada pretvarača, odnosno radnoj točki određenoj njegovom izlaznom strujom

Automatic Generation Control Application for Transmission and Generation Centres

Recently, a new Emergency Control Centre for Albanian Transmission System Operator (TSO), which includes Supervisory control and data acquisition (SCADA) and Automatic Generation Control (AGC) applications, has been commissioned. Nowadays, an AGC application is being prepared for the biggest generation company in Croatia, as part of control centre for hydropower plants within western part of Croatia. Both of these implementations use the same AGC application, which is presented in this paper. Although AGC for TSO and AGC for Generation Centre (GC) have many similarities, their main goals are different. AGC for TSO must mainly regulate system’s frequency and area’s active power interchange to their desired values, using only power plants engaged in load-frequency control (LFC). However, AGC for GC must ensure that power production of each power unit not engaged in LFC tracks its planned value, while also ensuring that centre’s share in LFC is being respected. Albeit the AGC is standalone application, in both afore-mentioned implementations it is affiliated with SCADA application, from which it obtains all required input measurements and indications and to which it delivers calculated setpoints. Additionally, all AGC pictures are integrated into SCADA pictures as well, in order to simplify operation and monitoring functionalities. AGC for Albanian TSO controls active power generation of six hydro power plants engaged in LFC. AGC for GC West in Croatia controls active power generation of ten hydro power plants. In both implementations, communication with remote objects is done using IEC 60870-5-104 communication protocol, while communication with other control centres is done using ICCP communication protocol. Power production plans are sent to AGC either from Market Management Systems (in TSO case) or from scheduling and optimization application (in GC case

Odnos strukture i aktivnosti u reaktivaciji tabunom fosforilirane ljudske acetilkolinesteraze bispiridinijevim para-aldoksimima

We investigated interactions of bispyridinium para-aldoximes N,N’-(propano)bis(4-hydroxyiminomethyl) pyridinium bromide (TMB-4), N,N’-(ethano)bis(4-hydroxyiminomethyl)pyridinium methanosulphonate (DMB-4), and N,N’-(methano)bis(4-hydroxyiminomethyl)pyridinium chloride (MMB-4) with human erythrocyte acetylcholinesterase phosphorylated by tabun. We analysed aldoxime conformations to determine the flexibility of aldoxime as an important feature for binding to the acetylcholinesterase active site. Tabun-inhibited human erythrocyte acetylcholinesterase was completely reactivated only by the most flexible bispyridinium aldoxime - TMB-4 with a propylene chain between two rings. Shorter linkers than propylene (methylene or ethylene) as in MMB-4 and DMB-4 did not allow appropriate orientation in the active site, and MMB-4 and DMB-4 were not efficient reactivators of tabun-phosphorylated acetylcholinesterase. Since aldoximes are also reversible inhibitors of native acetylcholinesterase, we determined dissociation constants and their protective index against acetylcholinesterase inactivation by tabun.Proučavali smo interakcije bispiridinijevih para-oksima N,N’-(propano)bis(4-hidroksiiminometil)piridinijeva bromida (TMB-4), N,N’-(etanano)bis(4-hidroksiiminometil)piridinijeva metanosulfonata (DMB-4) i N,N’- (metano)bis(4-hidroksiiminometil)piridinijeva klorida (MMB-4) s ljudskom eritrocitnom acetilkolinesterazom fosforiliranom tabunom. Da bismo odredili fleksibilnosti aldoksima, što je važna osobina kod njihova vezanja u aktivno mjesto acetilkolinesteraze, analizirali smo i konformacijske odlike aldoksima. Ljudska acetilkolinesteraza inhibirana tabunom bila je potpuno reaktivirana samo najfleksibilnijim bispiridinijevim aldoksimom – TMB-4. Aldoksimi MMB-4 i DMB-4 nisu bili efikasni reaktivatori acetilkolinesteraze fosforilirane tabunom jer je kod tih spojeva lanac koji povezuje dva prstena kraći od propilena (metilen u MMB-4 i etilen u DMB-4), što ne dopušta povoljnu orijentaciju tih aldoksima unutar aktivnog mjesta enzima. S obzirom na to da su aldoksimi i reverzibilni inhibitori nativne acetilkolinesteraze, odredili smo njihove disocijacijske konstante, kao i zaštitu acetilkolinesteraze od inhibiranja tabunom reverzibilnim vezanjem aldoksima

Microneedles: A New Frontier in Nanomedicine Delivery

This review aims to concisely chart the development of two individual research fields, namely nanomedicines, with specific emphasis on nanoparticles (NP) and microparticles (MP), and microneedle (MN) technologies, which have, in the recent past, been exploited in combinatorial approaches for the efficient delivery of a variety of medicinal agents across the skin. This is an emerging and exciting area of pharmaceutical sciences research within the remit of transdermal drug delivery and as such will undoubtedly continue to grow with the emergence of new formulation and fabrication methodologies for particles and MN. Firstly, the fundamental aspects of skin architecture and structure are outlined, with particular reference to their influence on NP and MP penetration. Following on from this, a variety of different particles are described, as are the diverse range of MN modalities currently under development. The review concludes by highlighting some of the novel delivery systems which have been described in the literature exploiting these two approaches and directs the reader towards emerging uses for nanomedicines in combination with MN