Incorporação de um sistema nobreak com ultracapacitor em um microcomputador

The objective of this work is to analyze the viability of incorporation in a microcomputer box of a nobreak with an ultracapacitor as energy storage device, substituting the conventional chemical battery. An advantage of this inclusion is cost reduction because a specific metallic or plastic frame won’t be necessary to protect the components of the nobreak; the microcomputer metallic frame offers the necessary protection for both equipments. Moreover, a large quantity of internal space of microcomputers box isn’t used, and is possible to use it to wrap up the nobreak. This work uses data about average power consumption of microcomputers; operation of switching mode power supplies for microcomputers; electrical and mechanical characteristics of ultracapacitors and operation of power circuits of nobreaks, with the purpose of present a study of energy storage capacity that an ultracapacitor should have to allow a safe switching off of a microcomputer in case of electrical network fail. It was noticed that the use of ultracapacitors is feasible to feed an 180 W load for 75 s, using a capacitive bank with sixteen ultracapacitors, with a total capacitance of 350 F and voltage of 10,8 V. The use of the proposed nobreak increases the reliability of the microcomputer by reducing the probability of user data losses in case of an electrical network fail, offering a high cost/benefit product. The substitution of the battery by an ultracapacitor allows a quick nobreak recharge, with low maintenance costs, since ultracapacitors have a lifetime bigger than batteries; beyond reducing the environmental impact, because they don’t use potentially toxic chemical compounds

Toimistorakennuksen ja lääkevaraston sähkönsyöttö kriisitilanteessa

Tämän insinöörityön kohteena on Tamro Oyj:n Vantaalla sijaitseva varasto- ja toimistorakennus Tamrotalo. Työn tarkoituksena on laatia ohjeistus sähkölaitteistoihin kohdistuvista toimenpiteistä siinä tapauksessa, että sähkönjakelu on katkennut valtakunnanverkon osalta, eli sähkönsyöttö Vantaan Energian sähköverkossa on poikki. Työssä tutkitaan kiinteistön nykyisen sähköverkon tilanne varmennetun verkon kannalta mittaamalla kuormituksia, haastattelemalla sekä kartoittamalla sähkönjakeluverkosto. Saatujen tietojen perusteella pyritään tutkimaan onko mahdollista osittain vähentää kuormitusta tai onko tarvetta kytkeä lisää laitteita varmennettuun verkkoon. Näiden tietojen pohjalta laadittiin toimintaohje huoltohenkilökunnalle, jonka avulla on tarkoitus saattaa kiinteistö toimintakuntoiseksi sähkökatkosten aikana. Lopussa on esitetty parannusehdotuksia, joilla kiinteistön toimivuutta pystyttäisiin vahvistamaan. Lisäksi on huomioitu tutkintavaiheessa ilmenneitä epäkohtia kiinteistön sähkönsyötöissä.

Novel biological roles for pyrimidines

The development of classical and lipophilic inhibitors of dihydrofolate reductase (DHFR) as antitumour agents is reviewed and the advantages and problems associated with each class are discussed. The antitumour activity, pharmacokinetics and metabolism of m-azido-pyrimethamine (MZP), a novel lipophilic inhibitor, are considered and compared with metoprine, the prototype lipophilic antifolate. Evidence for a folate-independent target for lipophilic DHFR inhibitors is presented. Synthetic studies centred on three principal objectives. Firstly a series of structural analogues of MZP were prepared encompassing alkoxy, chloro and alkylamino substituents and evaluated, as the ethanesulphonate salts, for activity against mammalian DHFR. Inhibitory constant (KI) determinations were conducted by a Zone B analysis, the corresponding 4'-azido isomer of MZP proving more potent than the parent compound. Secondly, to facilitate metabolism and stability studies on MZP, a range of possible reference compounds were synthesised and characterised. Finally, a series of diaminopyrimidine derivatives were synthesised embracing structural features incompatible with DHFR inhibitory activity, in order that such compounds may serve as biochemical probes for the unidentified folate-independent target for lipophilic diaminopyrimidines discussed previously. Inactivity against DHFR was achieved via introduction of an ionic or basic group into a normally hydrophobic region of the molecule and compounds were screened against a mammalian DHFR and thymidylate synthase to confirm the abolition of activity. Several derivatives surprisingly proved potent inhibitors of DHFR exhibiting KI values comparable to that of methotrexate. Analogues were screened for antitumour activity in vitro and in vivo against murine leukaemia cell lines in order to identify potential lead compounds. Several derivatives virtually inactive against DHFR exhibited a disparate cytotoxicity and further biochemical studies are warranted. The nobreak hitherto unreported debenzylation of 2,4-diamino-5-(N-alkyl-benzylaminophenyl) pyrimidines was discovered during the course of the synthetic studies, treatment of these compounds with nitrous acid affording the corresponding benzotriazoles.