24 research outputs found
Proizvodnja vodika elektrolizom vode pomoÄu sunÄeve energije i fotonaponskog modula
Proizvodnja elektriÄne energije direktnom pretvorbom SunÄeve energije bez popratne emisije ugljikovog dioksida (CO2) bitna je s motriÅ”ta sigurnosti opskrbe, ali i s motriÅ”ta zaÅ”tite okoliÅ”a. Osnovne tehnoloÅ”ke komponente u sustavu kojima se danas može rijeÅ”iti takav zadatak su fotonaponski (F\N) Älanak, elektrolizator, spremnik vodika, vodikov gorivni Älanak te voda kao osnovni radni medij. Zbog svega toga u fokusu ove doktorske disertacije nalazi se konstrukcija eksperimentalnog elektrolitiÄkog Älanka s otopinom kalijevog hidroksida (KOH) u vodi (alkalna otopina, lužina) kao elektrolitom. U okviru testiranja elektrolizatora snimljena je njegova radna (UI) karakteristika i izraÄunata iskoristivost koja je u okvirima poznatima iz literature. UoÄeno je da se na intenzitet proizvodnje vodika može utjecati promjenom brzine kruženja elektrolita kroz porozne elektrode Älanka. Osim originalnog dijela ove doktorske disertacije prikazan je i pregled povijesnog razvoja alkalnih elektrolizatora i opisi poznatih tehniÄkih koncepata njihove izvedbe. U sustavu za proizvodnju vodika elektrolizom vode pomoÄu SunÄeve energije i fotonaponskog Älanka (F\NH2 sustav) istraživanja se odnose na eksperimentalno mjerenje i modeliranje F\N Älanka i elektrolizatora pojedinaÄno i spregnutih u jedan zajedniÄki sustav. Cilj je poboljÅ”anje iskoristivosti i pojednostavljenje sustava. Istraživanja na F\N Älanku provode se u svrhu definiranja utjecaja razliÄitih parametara na njegovu UI karakteristiku i putanju toÄke maksimalne snage (MPP putanja). MPP putanja je putanja toÄke maksimalne snage u realnim uvjetima promjenljivog globalnog osunÄanja. S istim ciljem istražuje se i alkalni elektrolizator takoÄer eksperimentalno i numeriÄkim simulacijama. Iz istraživanih matematiÄkih modela sustava dobiven je uvid u osnovne parametre potrebne za konstrukciju cijelog sustava, a prvenstveno elektrolizatora. U Å”irem smislu, rezultat istraživanja je i doprinos razvoju metode usklaÄivanja ova dva sustava (elektrolizator i F\N modul) u jedan sustav koji je jednostavniji, pouzdaniji, jeftiniji i uÄinkovitiji od sliÄnih postojeÄih sustava za proizvodnju vodika bez popratne emisije CO2
Antioxidative effect of nerve growth factor (NGF) in rat thalamus after quinolinic acid-induced neurotoxicity
Quinolinic acid (QA) produces a pattern of selective cell loss in the striatum, that closely mimics that of Huntington's disease (HD). The aim of this study was to investigate the antioxidative status in the thalamus after intrastriatal application of QA and the influence of nerve growth factor (NGF) on such neurotoxicity. Wistar rats were treated intrastriatally (coordinates: 8.4A, 2.6L, 4.8V), using a stereotaxic instrument. The first group was treated with QA (150 nmol/l). The second group was treated with QA, followed by NGF (4.5 mg/kg b.w). The control group was treated with 0.9 % saline solution. Seven days after the treatment, we found decreased superoxide dismutase (SOD) activity in mitochondrial fractions of the striatum of both groups. In the thalamus, SOD activity showed no differences. The content of superoxide anion increased in the striatum of QA- treated animals. It was decreased in both structures in the group that was treated with QA and NGF. In the QA+ NGF-treated group, we found increased glutathione peroxidase (GSHPx) and GSH, compared to the group that was treated with QA only, but these values were lower than in the controls. Thus, NGF showed beneficial effects on the oxido-reduction status in the striatum, and also in the thalamus, a structure that is separated from but tightly connected with the striatum.Hinolinska kiselina (HK) prouzrokuje takav selektivni gubitak Äelija u strijatumu, koji veoma dobro imitira onaj kod Huntingtonove bolesti. Cilj ovog istraživanja bio je da se ispita antioksidativni status u talamusu nakon aplikacije HK u strijatum i uticaj NGF na takvu neurotoksiÄnost. Wistar pacovi su tretirani intrastrijatno, pomoÄu stereotaksiÄnog instrumenta (koordinate: 8,4A, 2,6L, 4,8V). Prva grupa je bila tretirana HK (150 nmol/l). Druga grupa je bila tretirana HK, a nakon toga je dobila NGF (4.5 mg/ kg b.w). Kontrolna grupa je bila tretirana fizioloÅ”kim rastvorom. Sedam dana nakon tretmana, u mitohondrijskim frakcijama strijatuma, naÅ”li smo smanjenu aktivnost SOD u obema grupama. U talamusu, aktivnost SOD se nije promenila. Sadržaj superoksidnog anjona se poveÄao u strijatumu životinja koje su bile tretirane HK, a smanjio se u obema strukturama, u grupi koja je bila tretirana sa HK i NGF. U HK+ NGF-tretiranoj grupi, naÅ”li smo poveÄanu aktivnost GSHPx i GSH u odnosu na grupu koja je bila tretirana samo sa HK, ali su te vrednosti bile manje u odnosu na kontrolne. NGF je pokazao povoljne efekte na oksido-reduktivni status u strijatumu, ali takoÄe i u talamusu, strukturi koja je odvojena, ali veoma blisko povezana sa strijatumom.nul
Efekat NGF na antioksidativnu odbranu u talamusu pacova nakon neurotoksiÄnog delovanja hinolinske kiseline
Quinolinic acid (QA) produces a pattern of selective cell loss in the striatum, that closely mimics that of Huntington's disease (HD). The aim of this study was to investigate the antioxidative status in the thalamus after intrastriatal application of QA and the influence of nerve growth factor (NGF) on such neurotoxicity. Wistar rats were treated intrastriatally (coordinates: 8.4A, 2.6L, 4.8V), using a stereotaxic instrument. The first group was treated with QA (150 nmol/l). The second group was treated with QA, followed by NGF (4.5 mg/kg b.w). The control group was treated with 0.9 % saline solution. Seven days after the treatment, we found decreased superoxide dismutase (SOD) activity in mitochondrial fractions of the striatum of both groups. In the thalamus, SOD activity showed no differences. The content of superoxide anion increased in the striatum of QA- treated animals. It was decreased in both structures in the group that was treated with QA and NGF. In the QA+ NGF-treated group, we found increased glutathione peroxidase (GSHPx) and GSH, compared to the group that was treated with QA only, but these values were lower than in the controls. Thus, NGF showed beneficial effects on the oxido-reduction status in the striatum, and also in the thalamus, a structure that is separated from but tightly connected with the striatum.Hinolinska kiselina (HK) prouzrokuje takav selektivni gubitak Äelija u strijatumu, koji veoma dobro imitira onaj kod Huntingtonove bolesti. Cilj ovog istraživanja bio je da se ispita antioksidativni status u talamusu nakon aplikacije HK u strijatum i uticaj NGF na takvu neurotoksiÄnost. Wistar pacovi su tretirani intrastrijatno, pomoÄu stereotaksiÄnog instrumenta (koordinate: 8,4A, 2,6L, 4,8V). Prva grupa je bila tretirana HK (150 nmol/l). Druga grupa je bila tretirana HK, a nakon toga je dobila NGF (4.5 mg/ kg b.w). Kontrolna grupa je bila tretirana fizioloÅ”kim rastvorom. Sedam dana nakon tretmana, u mitohondrijskim frakcijama strijatuma, naÅ”li smo smanjenu aktivnost SOD u obema grupama. U talamusu, aktivnost SOD se nije promenila. Sadržaj superoksidnog anjona se poveÄao u strijatumu životinja koje su bile tretirane HK, a smanjio se u obema strukturama, u grupi koja je bila tretirana sa HK i NGF. U HK+ NGF-tretiranoj grupi, naÅ”li smo poveÄanu aktivnost GSHPx i GSH u odnosu na grupu koja je bila tretirana samo sa HK, ali su te vrednosti bile manje u odnosu na kontrolne. NGF je pokazao povoljne efekte na oksido-reduktivni status u strijatumu, ali takoÄe i u talamusu, strukturi koja je odvojena, ali veoma blisko povezana sa strijatumom
Antioxidative effect of nerve growth factor (NGF) in rat thalamus after quinolinic acid-induced neurotoxicity
Quinolinic acid (QA) produces a pattern of selective cell loss in the striatum, that closely mimics that of Huntington's disease (HD). The aim of this study was to investigate the antioxidative status in the thalamus after intrastriatal application of QA and the influence of nerve growth factor (NGF) on such neurotoxicity. Wistar rats were treated intrastriatally (coordinates: 8.4A, 2.6L, 4.8V), using a stereotaxic instrument. The first group was treated with QA (150 nmol/l). The second group was treated with QA, followed by NGF (4.5 mg/kg b.w). The control group was treated with 0.9 % saline solution. Seven days after the treatment, we found decreased superoxide dismutase (SOD) activity in mitochondrial fractions of the striatum of both groups. In the thalamus, SOD activity showed no differences. The content of superoxide anion increased in the striatum of QA- treated animals. It was decreased in both structures in the group that was treated with QA and NGF. In the QA+ NGF-treated group, we found increased glutathione peroxidase (GSHPx) and GSH, compared to the group that was treated with QA only, but these values were lower than in the controls. Thus, NGF showed beneficial effects on the oxido-reduction status in the striatum, and also in the thalamus, a structure that is separated from but tightly connected with the striatum.Hinolinska kiselina (HK) prouzrokuje takav selektivni gubitak Äelija u strijatumu, koji veoma dobro imitira onaj kod Huntingtonove bolesti. Cilj ovog istraživanja bio je da se ispita antioksidativni status u talamusu nakon aplikacije HK u strijatum i uticaj NGF na takvu neurotoksiÄnost. Wistar pacovi su tretirani intrastrijatno, pomoÄu stereotaksiÄnog instrumenta (koordinate: 8,4A, 2,6L, 4,8V). Prva grupa je bila tretirana HK (150 nmol/l). Druga grupa je bila tretirana HK, a nakon toga je dobila NGF (4.5 mg/ kg b.w). Kontrolna grupa je bila tretirana fizioloÅ”kim rastvorom. Sedam dana nakon tretmana, u mitohondrijskim frakcijama strijatuma, naÅ”li smo smanjenu aktivnost SOD u obema grupama. U talamusu, aktivnost SOD se nije promenila. Sadržaj superoksidnog anjona se poveÄao u strijatumu životinja koje su bile tretirane HK, a smanjio se u obema strukturama, u grupi koja je bila tretirana sa HK i NGF. U HK+ NGF-tretiranoj grupi, naÅ”li smo poveÄanu aktivnost GSHPx i GSH u odnosu na grupu koja je bila tretirana samo sa HK, ali su te vrednosti bile manje u odnosu na kontrolne. NGF je pokazao povoljne efekte na oksido-reduktivni status u strijatumu, ali takoÄe i u talamusu, strukturi koja je odvojena, ali veoma blisko povezana sa strijatumom.nul
AN INVESTIGATION INTO THE EFFECT OF PHOTOVOLTAIC MODULE ELECTRIC PROPERTIES ON MAXIMUM POWER POINT TRAJECTORY WITH THE AIM OF ITS ALIGNMENT WITH ELECTROLYZER U-I CHARACTERISTIC
In order to combine a photovoltaic module and an electrolyzer to produce hydrogen from water, an intermediate DC/DC converter can be used to adapt output power features of the module to input power features of the electrolyzer. This can also be done without using electronics, which results in saving as much as 700 USD/kW, as previous investigation has shown. A more sophisticated investigation should be carried out with the aim of improving high system efficiency, resulting in matching the photovoltaic module maximum power point trajectory (the maximum power point path in the U-I plane as a result of solar irradiance change) to the operating characteristic of the electrolyzer. This paper presents an analysis of the influences of photovoltaic module electric properties, such as series and parallel resistance and non-ideality factor, on the maximum power point trajectory at different levels of solar irradiance. The possibility of various inclinations (right - vertical - left) in relation to an arbitrary chosen operating characteristic of the electrolyzer is also demonstrated. Simulated results are obtained by using Matlab/Simulink simulations of the well known one-diode model. Simulations have been confirmed with experiments on a real photovoltaic module where solar irradiance, solar cell temperature, electric current, and voltage in the circuit with variable ohmic resistance have been measured