Search results for "NO2"
showing 8 items of 38 documents
Chromatographic Air Analyzer Microsystem for the Selective and Sensitive Detection of Explosive-related Compounds
2014
Abstract The detection of explosives and explosive-related compounds is of major importance for the monitoring of explosive- contaminated sites. Current methods need to become cheaper and portable while maintaining a high sensitivity and selectivity level. In that sense, a silicon micro-analytical platform consisting of a three-dimensional micro-preconcentrator based on a hydrophobic zeolite, coupled to a silicon spiral micro-column was built. A chemical gas sensor acted as a miniaturized gas detector. This system allowed selective detection of orthonitrotoluene (ONT), an explosive-related compound at the sub-ppm level in the presence of toluene and moisture.
Changes in atmospheric pollutants during COVID-19
2022
Bakalaura darba “Atmosfēras piesārņojuma izmaiņas COVID-19 laikā” mērķis –Identificēt un izpētīt ar COVID-19 pandēmiju saistītās izmaiņas, konkrēti, pārvietošanās ierobežojumu un dzīves veida izmaiņu, ietekmi attiecībā uz atmosfēras piesārņojuma koncentrāciju rādītājiem Latvijas Republikas galvaspilsētā Rīgā. Pētījumā analizēti dati no Latvijas Ģeoloģijas un Meteoroloģijas (LVĢMC) centra novērojumu stacijām. COVID-19 pandēmijas ietekme bija jūtama visā pasaulē, tostarp arī Eiropā, jo ārkārtas stāvokļa un pārvietošanās ierobežojumu rezultātā bija vērojamas izmaiņas emisiju dinamikā atmosfērā. Sakarā ar izmaiņām darba norisē un darbinieku pāreju uz attālināto darbu, kā arī mācību un studiju p…
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
2021
Financial support provided by Scientific Research Project for Students and Young Researchers, Latvia Nr. SJZ/2018/7 realized at the Institute of Solid State Physics, University of Latvia is greatly acknowledged. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.
Graphene films for gas sensing applications
2013
Gas detection at small concentrations is usually done using transition metal oxides. These semiconductors are, however, strongly dependent on parameters and conditions of growth and processing. Graphene attracts a big interest in science and technology due to its exceptional electric properties, and this truly 2-dimensional material has a great promise to be used as highly sensitive gas sensor. In this thesis, CVD and epitaxial graphene samples have been investigated in order to improve their sensitivity in gas sensing applications. The response of the sensor to different concentrations of detected gas was observed as a relative change of resistance of the sample. The aim of this study was …
A new simple chromo-fluorogenic probe for NO2 detection in air.
2015
[EN] A new chromo-fluorogenic probe, consisting of a biphenyl derivative containing both a silylbenzyl ether and a N,N-dimethylamino group, for NO2 detection in the gas phase has been developed. A clear colour change from colourless to yellow together with an emission quenching was observed when the probe reacted with NO2. A limit of detection to the naked eye of about 0.1 ppm was determined and the system was successfully applied to the detection of NO2 in realistic atmospheric conditions.
DFT insights into the oxygen-assisted selective oxidation of benzyl alcohol on manganese dioxide catalysts
2020
Abstract The reactivity pattern of the MnO2 catalyst in the selective aerobic oxidation of benzyl alcohol is assessed by density functional theory (DFT) analysis of adsorption energies and activation barriers on a model Mn4O8 cluster. DFT calculations predict high reactivity of defective Mn(IV) sites ruling a surface redox mechanism, L-H type, involving gas-phase oxygen. Bare and promoted (i.e., CeOx and FeOx) MnOx materials with high surface exposure of Mn(IV) sites were synthesized to assess kinetic and mechanistic issues of the selective aerobic oxidation of benzyl alcohol on real catalysts (T, 333–363 K). According to DFT predictions, the experimental study shows: i) comparable activity…
Transporta plūsmu kustības ātruma un strukturālo izmaiņu modelēšana Valdemāra ielas kanjona posmos
2015
Bakalaura darba ietvaros pētīta autotransporta radītā atmosfēras piesārņojuma izplatība Rīgā, Valdemāra ielas kanjonā. Kā indikators ietekmes novērtēšanai izmantotas slāpekļa dioksīda koncentrācijas, kuras cieši korelē ar transporta līdzekļu plūsmas intensitāti; bez tam regulāri tiek pārsniegti slāpekļa dioksīdam noteiktie stundas un gada normatīvi. Piesārņojuma izplatība novērtēta izmantojot matemātisko modelis OSPM, kurš speciāli izstrādāts transporta radītā piesārņojuma dispersijai un raksturošanai. Darbā aprakstīta transporta plūsmas dinamika dažādiem dienu profiliem un izveidota datu bāze modelēšanai, raksturota piesārņojuma problemātika ielu kanjonos, modelēšanas ceļā novērtēta apbūve…
Innovative Approaches for Organizing an Inclusive Optics and Photonics Conference in Virtual Format
2023
The COVID pandemic is forcing the renewal of scientific conferences, offering opportunities to introduce technological and inclusive developments. Our analysis focuses on the implementation of inclusive practices for female and early-career researchers in a virtual scientific conference. This organization approach was applied in the XIII Spanish Optical Meeting (RNO2021), which was also characterized by avatars interacting in an online metaverse. The effectiveness of inclusive policies and novel technological tools was evaluated using the participation data and a post-conference survey. Our study reveals the high impact of inclusive actions and a strong interest in the scientific community …