Spatially and temporally resolved spectroscopic characterization of low pressure cold plasmas

U ovoj disertaciji predstavlja se izrada i primjena novog eksperimentalnog uređaja za obradu uzoraka pomoću induktivno vezane niskotlačne hladne plazme. Uređaj omogućuje praćenje i karakterizaciju procesa međudjelovanja hladne plazme s površinom uzorka. Primarna metoda karakterizacije je optička emisijska spektroskopija. Spektralne značajke plazme su prostorno i vremenski razlučene pomoću minijaturnih spektrometara. Spektralna karakterizacija plazme je uspoređena s mjerenjima koncentracije atoma pomoću katalitičkih sondi. Izmjereni parametri korišteni su za optimizaciju procesa međudjelovanja hladne plazme i uzorka, a posebna pozornost usmjerena je na istraživanje povratnog utjecaja uzorka na plazmu.This dissertation presents the development of a new experimental device for low pressure inductively coupled cold plasma sample processing. The device enables monitoring and characterization of the process of cold plasma interactions with the surface of the sample. Primary method of characterization is optical emission spectroscopy. Spectral characteristics of plasma are spatially and temporally resolved using miniature spectrometers. Spectral characterization of plasma is compared with measurements of the concentration of atoms with catalytic probes. The measured parameters are used to optimize the process of interaction between the cold plasma and the sample, and special attention is focused on the sample influence on plasma. Investigations included spatially resolved spectroscopy of oxygen, water vapour and hydrogen plasmas. Methane plasma and the deposition of amorphous carbon films and its subsequent removal by oxygen plasma was investigated by optical emission spectroscopy and pirometry. Numerous materials were introduced into various plasmas. These include: ammonia plasma and its effect on sodium hyaluronate (effects on the samples were analysed by XPS). Also, characteristics of oxygen plasma during treatment of polymer graphite composite were monitored by optical emission spectroscopy. Investigation of dental posts modification in hydrogen plasma was performed, where similar effect to classical methods in their pretreatment was achieved. Various polymers (PP, PVC, PTFE and many other) were monitored during plasma treatment by oxygen, hydrogen and argon plasmas. Oxygen plasma was also used in the treatment and modification of surface characteristics of cotton

Spatially and temporally resolved spectroscopic characterization of low pressure cold plasmas

U ovoj disertaciji predstavlja se izrada i primjena novog eksperimentalnog uređaja za obradu uzoraka pomoću induktivno vezane niskotlačne hladne plazme. Uređaj omogućuje praćenje i karakterizaciju procesa međudjelovanja hladne plazme s površinom uzorka. Primarna metoda karakterizacije je optička emisijska spektroskopija. Spektralne značajke plazme su prostorno i vremenski razlučene pomoću minijaturnih spektrometara. Spektralna karakterizacija plazme je uspoređena s mjerenjima koncentracije atoma pomoću katalitičkih sondi. Izmjereni parametri korišteni su za optimizaciju procesa međudjelovanja hladne plazme i uzorka, a posebna pozornost usmjerena je na istraživanje povratnog utjecaja uzorka na plazmu.This dissertation presents the development of a new experimental device for low pressure inductively coupled cold plasma sample processing. The device enables monitoring and characterization of the process of cold plasma interactions with the surface of the sample. Primary method of characterization is optical emission spectroscopy. Spectral characteristics of plasma are spatially and temporally resolved using miniature spectrometers. Spectral characterization of plasma is compared with measurements of the concentration of atoms with catalytic probes. The measured parameters are used to optimize the process of interaction between the cold plasma and the sample, and special attention is focused on the sample influence on plasma. Investigations included spatially resolved spectroscopy of oxygen, water vapour and hydrogen plasmas. Methane plasma and the deposition of amorphous carbon films and its subsequent removal by oxygen plasma was investigated by optical emission spectroscopy and pirometry. Numerous materials were introduced into various plasmas. These include: ammonia plasma and its effect on sodium hyaluronate (effects on the samples were analysed by XPS). Also, characteristics of oxygen plasma during treatment of polymer graphite composite were monitored by optical emission spectroscopy. Investigation of dental posts modification in hydrogen plasma was performed, where similar effect to classical methods in their pretreatment was achieved. Various polymers (PP, PVC, PTFE and many other) were monitored during plasma treatment by oxygen, hydrogen and argon plasmas. Oxygen plasma was also used in the treatment and modification of surface characteristics of cotton

Spatially and temporally resolved spectroscopic characterization of low pressure cold plasmas

U ovoj disertaciji predstavlja se izrada i primjena novog eksperimentalnog uređaja za obradu uzoraka pomoću induktivno vezane niskotlačne hladne plazme. Uređaj omogućuje praćenje i karakterizaciju procesa međudjelovanja hladne plazme s površinom uzorka. Primarna metoda karakterizacije je optička emisijska spektroskopija. Spektralne značajke plazme su prostorno i vremenski razlučene pomoću minijaturnih spektrometara. Spektralna karakterizacija plazme je uspoređena s mjerenjima koncentracije atoma pomoću katalitičkih sondi. Izmjereni parametri korišteni su za optimizaciju procesa međudjelovanja hladne plazme i uzorka, a posebna pozornost usmjerena je na istraživanje povratnog utjecaja uzorka na plazmu.This dissertation presents the development of a new experimental device for low pressure inductively coupled cold plasma sample processing. The device enables monitoring and characterization of the process of cold plasma interactions with the surface of the sample. Primary method of characterization is optical emission spectroscopy. Spectral characteristics of plasma are spatially and temporally resolved using miniature spectrometers. Spectral characterization of plasma is compared with measurements of the concentration of atoms with catalytic probes. The measured parameters are used to optimize the process of interaction between the cold plasma and the sample, and special attention is focused on the sample influence on plasma. Investigations included spatially resolved spectroscopy of oxygen, water vapour and hydrogen plasmas. Methane plasma and the deposition of amorphous carbon films and its subsequent removal by oxygen plasma was investigated by optical emission spectroscopy and pirometry. Numerous materials were introduced into various plasmas. These include: ammonia plasma and its effect on sodium hyaluronate (effects on the samples were analysed by XPS). Also, characteristics of oxygen plasma during treatment of polymer graphite composite were monitored by optical emission spectroscopy. Investigation of dental posts modification in hydrogen plasma was performed, where similar effect to classical methods in their pretreatment was achieved. Various polymers (PP, PVC, PTFE and many other) were monitored during plasma treatment by oxygen, hydrogen and argon plasmas. Oxygen plasma was also used in the treatment and modification of surface characteristics of cotton

Influence of RF excitation during pulsed laser deposition in oxygen atmosphere on the structural properties and luminescence of nanocrystalline ZnO:Al thin films

Thin ZnO:Al layers were deposited by pulsed laser deposition in vacuum and in oxygen atmosphere at gas pressures between 10 and 70 Pa and by applying radio-frequency (RF) plasma. Grazing incidence small angle x-ray scattering and grazing incidence x-ray diffraction (GIXRD) data showed that an increase in the oxygen pressure leads to an increase in the roughness, a decrease in the sample density, and changes in the size distribution of nanovoids. The nanocrystal sizes estimated from GIXRD were around 20 nm, while the sizes of the nanovoids increased from 1 to 2 nm with the oxygen pressure. The RF plasma mainly influenced the nanostructural properties and point defects dynamics. The photoluminescence consisted of three contributions, ultraviolet (UV), blue emission due to Zn vacancies, and red emission, which are related to an excess of oxygen. The RF excitation lowered the defect level related to blue emission and narrowed the UV luminescence peak, which indicates an improvement of the structural ordering. The observed influence of the deposition conditions on the film properties is discussed as a consequence of two main effects: the variation of the energy transfer from the laser plume to the growing film and changes in the growth chemistry

On-road vehicle emissions beyond RDE conditions

Passenger cars are an important source of air pollution, especially in urban areas. Recently, real-driving emissions (RDE) test procedures have been introduced in the EU aiming to evaluate nitrogen oxides (NOx) and particulate number (PN) emissions from passenger cars during on-road operation. Although RDE accounts for a large variety of real-world driving, it excludes certain driving situations by setting boundary conditions (e.g., in relation to altitude, temperature or dynamic driving). The present work investigates the on-road emissions of NOx, NO2, CO, particle number (PN) and CO2 from a fleet of nineteen Euro 6b, 6c and 6d-TEMP vehicles, including diesel, gasoline (GDI and PFI) and compressed natural gas (CNG) vehicles. The vehicles were tested under different on-road driving conditions outside boundaries. These included ‘baseline’ tests, but also testing conditions beyond the RDE boundary conditions to investigate the performance of the emissions control devices in demanding situations. Consistently, low average emission rates of PN and CO were measured from all diesel vehicles tested under most conditions. Moreover, the tested Euro 6d-TEMP and Euro 6c diesel vehicles met the NOx emission limits applicable to Euro 6d-TEMP diesel vehicles during RDE tests (168 mg/km). The Euro 6b GDI vehicle equipped with a gasoline particulate filter (GPF) presented PN emissions < 6×1011 #/km. These results, in contrast with previous on-road measurements from earlier Euro 6 vehicles, indicate more efficient emission control technologies are currently being used in diesel and gasoline vehicles. However, the results described in this report also raise some new concerns. In particular, the emissions of CO (measured during the regulated RDE test, but without an emission limit associated to it) or PN from PFI vehicles (presently not covered by the Euro 6 standard) showed elevated results in some occasions. Emissions of CO were up to 7.5 times higher when the more dynamic tests were conducted and the highest PN emissions were measured from a PFI gasoline vehicle during dynamic driving. The work also investigates how NOx, CO, PN and CO2 on-road emissions from three vehicles are impacted by sub-zero ambient temperatures and high altitudes. Two of the tested vehicles were Euro 6d-TEMP certified vehicles, one diesel and one gasoline, and one was a Euro 6b plug-in hybrid vehicle. The vehicles were studied during tests that do not fulfil the boundary conditions in terms of maximum altitude, altitude gain, and/or minimum temperature. The obtained emissions were compared to those obtained during tests performed along RDE routes. The results indicate that cold ambient temperature and high altitude, outside the RDE boundary conditions, lead to in higher NOx, CO and PN emissions compared to moderate conditions of temperature and altitude. Nonetheless, the two Euro 6d-TEMP vehicles tested in those extreme conditions yielded NOx emissions factors that fulfilled the Euro 6d-TEMP emission requirements. Our work underlines the importance of a technology- and fuel-neutral approach to vehicle emission standards, whereby all vehicles must comply with the same emission limits for all pollutants.JRC.C.4-Sustainable Transpor

Framework for the assessment of PEMS (Portable Emissions Measurement Systems) uncertainty

European regulation 2016/427 (the first package of the so-called Real-Driving Emissions (RDE) regulation) introduced on-road testing with Portable Emissions Measurement Systems (PEMS) to complement the chassis dynamometer laboratory (Type I) test for the type approval of light-duty vehicles in the European Union since September 2017. The Not-To-Exceed (NTE) limit for a pollutant is the Type I test limit multiplied by a conformity factor that includes a margins for the additional measurement uncertainty of PEMS relative to standard laboratory equipment. The variability of measured results related to RDE trip design, vehicle operating conditions, and data evaluation remain outside of the uncertainty margin. The margins have to be reviewed annually (recital 10 of regulation 2016/646). This paper lays out the framework used for the first review of the NOx margin, which is also applicable to future margin reviews. Based on experimental data received from the stakeholders of the RDE technical working group in 2017, a NOx margin of 0.24 to 0.43 was calculated, accounting for different assumptions of possible zero drift behaviour of the PEMS during the tests. The reduced uncertainty margin compared to the one foreseen for 2020 (0.5) reflects the technical improvement of PEMS over the past few years.JRC.C.4-Sustainable Transpor

On-road emissions of passenger cars beyond the boundary conditions of the real-driving emissions test

Passenger cars are an important source of air pollution, especially in urban areas. Recently, real-driving emissions (RDE) test procedures have been introduced in the EU aiming to evaluate nitrogen oxides (NOx) and particulate number (PN) emissions from passenger cars during on-road operation. Although RDE accounts for a large variety of real-world driving, it excludes certain driving situations by setting boundary conditions (e.g., in relation to altitude, temperature or dynamic driving). The present work investigates the on-road emissions of NOx, NO2, CO, particle number (PN) and CO2 from a fleet of 19 Euro 6b, 6c and 6d-TEMP vehicles, including diesel, gasoline (GDI and PFI) and compressed natural gas (CNG) vehicles. The vehicles were tested under different on-road driving conditions outside boundaries. These included ‘baseline’ tests, but also testing conditions beyond the RDE boundary conditions to investigate the performance of the emissions control devices in demanding situations. Consistently low average emission rates of PN and CO were measured from all diesel vehicles tested under most conditions. Moreover, the tested Euro 6d-TEMP and Euro 6c diesel vehicles met the NOx emission limits applicable to Euro 6d-TEMP diesel vehicles during RDE tests (168 mg/km). The Euro 6b GDI vehicle equipped with a gasoline particulate filter (GPF) presented PN emissions < 6 × 1011 #/km. These results, in contrast with previous on-road measurements from earlier Euro 6 vehicles, indicate more efficient emission control technologies are currently being used in diesel and gasoline vehicles. At the same time, the results suggest that particular attention should be given to CO and PN emissions of certain types of vehicles when driven under dynamic conditions, and possibly additional work is necessary. In particular, the emissions of CO (measured in this study during the regulated RDE test, but without an emission limit associated to it) or PN from PFI vehicles (presently not covered by the Euro 6 standard) showed elevated results in some occasions. Emissions of CO were up to 7.5 times higher when the more dynamic tests were conducted and the highest PN emissions were measured from a PFI gasoline vehicle during dynamic driving. Although based on a limited sample of cars, our work points to the relevance of a technology- and fuel-neutral approach to vehicle emission standards, whereby all vehicles must comply with the same emission limits for all pollutants.JRC.C.4-Sustainable Transpor