We describe synthetic membranes in which the molecular recognition chemistry used to accomplish selective permeation is DNA hybridization. These membranes contain template-synthesized gold nanotubes ...with inside diameters of 12 nanometers, and a "transporter" DNA-hairpin molecule is attached to the inside walls of these nanotubes. These DNA-functionalized nanotube membranes selectively recognize and transport the DNA strand that is complementary to the transporter strand, relative to DNA strands that are not complementary to the transporter. Under optimal conditions, single-base mismatch transport selectivity can be obtained.
The objective of this work was to investigate the efficiency of imidazole derivatives for corrosion inhibition of copper in 0.5 M hydrochloric acid. Corrosion inhibition was studied using impedance ...spectroscopy. Imidazole and its derivatives 4-methylimidazole, 4-methyl-5-hydroxymethylimidazole, 1-phenyl-4-methylimidazole, 1-(p-tolyl)-4-methylimidazole were investigated. These studies have shown that 1-(p-tolyl)-4-methylimidazole is the best inhibitor in this series and that it acts as mixed inhibitor. The nature of the chemical interaction between these molecules and the copper surface was investigated for Cu exposed to solutions having two very different pH values: 0.5 M HCl and unbuffered purified water. X-ray photoelectron spectroscopy and secondary ion mass spectrometry were used to explore the nature of the interaction. Possible mechanisms of corrosion inhibition for these molecules are discussed.
The paper presents research on underexcited turbogenerator operation capability. Measurements of basic electrical values for various loads have been carried out in case of 247 MVA turbogenerator. ...Synchronous reactance for various loads has been determined from measurements. Its influence on underexcited operation limits has been evaluated.
The paper describes two specific transient phenomena of different characteristic frequencies. First, a short overview of a calculation of overvoltages in the generator main electrical circuit of a ...hydro power station is presented. A case of a generator connected to the step-up transformer through encapsulated lines has been studied. The most critical cases have been considered: overvoltages at a single phase earth fault in the generator circuit and temporary overvoltages due to the single phase earth fault followed by the load rejection. The calculations have been carried out by EMTP-ATP and MicroTran program. Second, electric power oscillations in hydro power plants are not rare. The paper shows two cases in two different power plants. Each power plant has different generator positions (one vertical and one horizontal bulb type) and therefore different reasons for power oscillations. An overview of those cases is presented supported by measurements and calculated by Matlab.
Endocarditis due to Abiotrophia sp. is rare and often associated with negative blood cultures. The rates of treatment failure, infection relapse and mortality are higher than in endocarditis caused ...by other viridans streptococci.
A retrospective review of A. defectiva endocarditis in a patient with prosthetic aortic valve and in a patient with Marfan syndrome was performed.
A. defectiva, susceptible to penicillin (MIC 0.064 mg/l and 0.016 mg/l, respectively) was isolated from blood cultures of both patients. Treatment with penicillin and gentamicin was started in both patients. Since the first patient developed a macular rash and leukopenia, penicillin was substituted with ceftriaxone. Both patients responded well to antibiotic treatment, did not need prosthetic valve insertion or reinsertion, and were without any sequelae at one year follow up.
Standard treatment of bacterial endocarditis with penicillin and gentamicin was effective in both patients. In contrast to previous reports, the present patients had a favorable outcome on completion of treatment and at one-year follow up.
The objective of this work was to investigate the efficiency of imidazole derivatives for corrosion inhibition of copper in 0.5 M hydrochloric acid. Corrosion inhibition was studied using impedance ...spectroscopy. Imidazole and its derivatives 4-methylimida-zole, 4-methyl-5-hydroxymethylimidazole, 1-phenyl-4-methylimidazole, 1-(p-tolyl)-4-methylimidazole were investigated. These studies have shown that 1-(p-tolyl)-4-methylimidazole is the best inhibitor in this series and that it acts as mixed inhibitor. The nature of the chemical interaction between these molecules and the copper surface was investigated by Cu exposed to solutions having two very different pH values: 0.5 M HCl and unbuffered purified water. X-ray photoelectron spectroscopy and secondary ion mass spectrometry were used to explore the nature of the interaction. Possible mechanisms of corrosion inhibition for these molecules are discussed.
U radu je predočena metodologija određivanja pogonske karte kao ključnog dokumenta svake proizvodne jedinice električne energije. Opisane su sve granice od kojih se sastoji pogonska karta ...hidrogeneratora. Detaljno su izložene teorijske podloge na kojima leže postupci za njihovo određivanje. Poseban osvrt je dan manj eistraženom problemu zagrijavanja čeonog prostora hidrogeneratora. Pregledno je prikazan i obrazložen slijed postupaka koji sačinjavaju metodologiju. Detaljne analize i proračuni, posebno korištenjem suvremenih numeričkih programskih alata, daju dobar uvid u mogućnost rada generatora i mogu poslužiti kao priprema za ispitivanja i mjerenja. Rezultati dobiveni mjerenjima i ispitivanjima obrađuju se i tumače, te se tek na osnovu tako dobivenih rezulatata sa sigurnošću određuju granice dozvoljenog rada generatora. Konačan rezulatat provođenja ispitivanja prema predloženoj metodologiji je korisnička pogonska karta: stvarna, mjerenjem potvrđena pogonska karta hidrogeneratora.
Power oscillations in hydropower units Maljkovic, Z.; Gasparac, I.; Vrazic, M.
2012 XXth International Conference on Electrical Machines,
2012-Sept.
Conference Proceeding
Electric power oscillations in hydro power plants are not rare. They can origin from lots of different reasons. This paper shows three cases in three different hydro power plants. Each power plant ...has different generator position (one vertical, one horizontal and one horizontal bulb type) and therefore different reasons for power oscillations. An overview of those cases is presented in this paper.
