14 research outputs found

    Ohjaus- ja tiedonkeruuohjelma automaattiseen integroitujen piirien evaluointiin

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    Automatic evaluation of integrated circuits can provide significant benefits and savings for a company compared to doing the evaluation manually. This paper describes a LabVIEW application called ATAC that was developed to automate evaluation of ASIC circuits. The same software can also be used to test integrated circuits in general in different hardware environments. A hardware setup for automatic ASIC evaluation is presented and it is used as basis for ATAC design. Presented software application ATAC can be used to control all hardware components in the evaluation setup but it can also be used without the hardware components. Hardware abstraction in ATAC makes it possible to use the same software solution in different environments with little modifications to the software code. The process of developing ATAC is presented as well as final application. Screenshots of GUI are presented as well as the underlying code using state chart presentation. The software was reviewed and assessed by end users who performed several ASIC evaluation tests using ATAC during the software development. An example case of an ASIC evaluation test is presented and the measurement results gathered with ATAC are discussed.Integroitujen piirien automaattinen evaluointi voi tuottaa huomattavia etuja ja säästöjä yhtiölle verrattuna evaluoinnin manuaaliseen suorittamiseen. Tässä opinnäytetyössä esitellään LabVIEW-sovellus nimeltään ATAC, joka kehitettiin automatisoimaan ASIC-piirien evaluointi. Samaa sovellusta voi käyttää myös muiden integroitujen piirien testaukseen erilaisissa laitteistoympäristöissä. Laitteisto ASIC-piirien automaattista evaluointia varten esitellään ja tämän laitteiston käyttöön ATAC lähtökohtaisesti suunniteltiin. Esitettyä ohjelmaa voi käyttää laitteiston kaikkien osien kontrollointiin, mutta ohjelmaa voi käyttää myös ilman laitteistokomponentteja. Laitteiston abstrahointi ATAC:ssa mahdollistaa ATAC:n käytön eri ympäristöissä ilman suuria muutoksia ohjelmakoodiin. ATAC:n kehitysprosessi sekä lopullinen ohjelma esitellään tässä opinnäytetyössä. Graafinen käyttöliittymä esitellään kuvakaappausten avulla ja koodi kuvaillaan käyttäen tilakaavioita. Ohjelman käytettävyyttä ja ohjelmankehitysprojektin onnistuneisuutta arvioidaan loppukäyttäjien kokemusten sekä todellisten ASIC-piirien evaluointimittausten tulosten perusteella. Esimerkki ASIC-piirin evaluointitestistä esitetään ja ATAC:n keräämiä mittaustuloksia arvioidaan

    Added Value of Vaisala AQT530 Sensors as a Part of a Sensor Network for Comprehensive Air Quality Monitoring

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    Poor air quality influences the quality of life in the urban environment. The regulatory observation stations provide the backbone for the city administration to monitor urban air quality. Recently a suite of cost-effective air quality sensors has emerged to provide novel insights into the spatio-temporal variability of aerosol particles and trace gases. Particularly in low concentrations these sensors might suffer from issues related e.g., to high detection limits, concentration drifts and interdependency between the observed trace gases and environmental parameters. In this study we characterize the optical particle detector used in AQT530 (Vaisala Ltd.) air quality sensor in the laboratory. We perform a measurement campaign with a network of AQT530 sensors in Helsinki, Finland in 2020-2021 and present a long-term performance evaluation of five sensors for particulate (PM10, PM2.5) and gaseous (NO2, NO, CO, O-3) components during a half-year co-location study with reference instruments at an urban traffic site. Furthermore, short-term (3-5 weeks) co-location tests were performed for 25 sensors to provide sensor-specific correction equations for the fine-tuning of selected pollutants in the sensor network. We showcase the added value of the verified network of 25 sensor units to address the spatial variability of trace gases and aerosol mass concentrations in an urban environment. The analysis assesses road and harbor traffic monitoring, local construction dust monitoring, aerosol concentrations from fireworks, impact of sub-urban small scale wood combustion and detection of long-range transport episodes on a city scale. Our analysis illustrates that the calibrated network of Vaisala AQT530 air quality sensors provide new insights into the spatio-temporal variability of air pollution within the city. This information is beneficial to, for example, optimization of road dust and construction dust emission control as well as provides data to tackle air quality problems arising from traffic exhaust and localized wood combustion emissions in the residential areas.Peer reviewe

    Lung deposited surface area size distributions of particulate matter in different urban areas

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    Lung deposited surface area (LDSA) concentration is considered as a relevant metric for the negative health effects of aerosol particles. We report for the first time the size distributions of the LDSA measured in urban air. The measurements were carried out in the metropolitan area of Helsinki, including mobile laboratory and stationary measurements in different outdoor environments, such as traffic sites, a park area, the city center and residential areas. The main instrument in this study was an electrical low pressure impactor (ELPI), which was calibrated in the field to measure the LDSA concentration. The calibration factor was determined to be 60 μm2/(cm3 pA). In the experiments, the LDSA size distributions were found to form two modes at the traffic sites and in the city center. Both of these traffic related particle modes, the nucleation mode and the soot mode, had a clear contribution to the total LDSA concentration. The average total concentrations varied from 12 to 94 μm2/cm3, measured in the park area and at the traffic site next to a major road, respectively. The LDSA concentration was found to correlate with the mass of fine particles (PM2.5), but the relation of these two metrics varied between different environments, emphasizing the influence of traffic on the LDSA. The results of this study provide valuable information on the total concentrations and size distributions of the LDSA for epidemiological studies. The size distributions are especially important in estimating the contribution of outdoor concentrations on the concentrations inside buildings and vehicles through size-dependent penetration factors.publishedVersionPeer reviewe

    Vertical profiles of lung deposited surface area concentration of particulate matter measured with a drone in a street canyon

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    The vertical profiles of lung deposited surface area (LDSA) concentration were measured in an urban street canyon in Helsinki, Finland, by using an unmanned aerial system (UAS) as a moving measurement platform. The street canyon can be classified as an avenue canyon with an aspect ratio of 0.45 and the UAS was a multirotor drone especially modified for emission measurements. In the experiments of this study, the drone was equipped with a small diffusion charge sensor capable of measuring the alveolar LDSA concentration of particles. The drone measurements were conducted during two days on the same spatial location at the kerbside of the street canyon by flying vertically from the ground level up to an altitude of 50 m clearly above the rooftop level (19 m) of the nearest buildings. The drone data were supported by simultaneous measurements and by a two-week period of measurements at nearby locations with various instruments. The results showed that the averaged LDSA concentrations decreased approximately from 60 μm2/cm3 measured close to the ground level to 36–40 μm2/cm3 measured close to the rooftop level of the street canyon, and further to 16–26 μm2/cm3 measured at 50 m. The high-resolution measurement data enabled an accurate analysis of the functional form of vertical profiles both in the street canyon and above the rooftop level. In both of these regions, exponential fits were used and the parameters obtained from the fits were thoroughly compared to the values found in literature. The results of this study indicated that the role of turbulent mixing caused by traffic was emphasized compared to the street canyon vortex as a driving force of the dispersion. In addition, the vertical profiles above the rooftop level showed a similar exponential decay compared to the profiles measured inside the street canyon. The high-resolution vertical profiles of lung deposited surface area obtained in this study are valuable with respect to exposure estimations, urban planning, and urban air quality models.acceptedVersionPeer reviewe

    Genomewide Association Study of Simvastatin Pharmacokinetics

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    We investigated genetic determinants of single-dose simvastatin pharmacokinetics in a prospective study of 170 subjects and a retrospective cohort of 59 healthy volunteers. In a microarray-based genomewide association study with the prospective data, the SLCO1B1 c.521T>C (p.Val174Ala, rs4149056) single nucleotide variation showed the strongest, genomewide significant association with the area under the plasma simvastatin acid concentration-time curve (AUC; P = 6.0 x 10(-10)). Meta-analysis with the retrospective cohort strengthened the association (P = 1.6 x 10(-17)). In a stepwise linear regression candidate gene analysis among all 229 participants, SLCO1B1 c.521T>C (P = 1.9 x 10(-13)) and CYP3A4 c.664T>C (p.Ser222Pro, rs55785340, CYP3A4*2, P = 0.023) were associated with increased simvastatin acid AUC. Moreover, the SLCO1B1 c.463C>A (p.Pro155Thr, rs11045819, P = 7.2 x 10(-6)) and c.1929A>C (p.Leu643Phe, rs34671512, P = 5.3 x 10(-4)) variants associated with decreased simvastatin acid AUC. Based on these results and the literature, we classified the volunteers into genotype-predicted OATP1B1 and CYP3A4 phenotype groups. Compared with the normal OATP1B1 function group, simvastatin acid AUC was 273% larger in the poor (90% confidence interval (CI), 137%, 488%; P = 3.1 x 10(-6)), 40% larger in the decreased (90% CI, 8%, 83%; P = 0.036), and 67% smaller in the highly increased function group (90% CI, 46%, 80%; P = 2.4 x 10(-4)). Intermediate CYP3A4 metabolizers (i.e., heterozygous carriers of either CYP3A4*2 or CYP3A4*22 (rs35599367)), had 87% (90% CI, 39%, 152%, P = 6.4 x 10(-4)) larger simvastatin acid AUC than normal metabolizers. These data suggest that in addition to no function SLCO1B1 variants, increased function SLCO1B1 variants and reduced function CYP3A4 variants may affect the pharmacokinetics, efficacy, and safety of simvastatin. Care is warranted if simvastatin is prescribed to patients carrying decreased function SLCO1B1 or CYP3A4 alleles.Peer reviewe

    Sub-23 nm Particles Dominate Non-Volatile Particle Number Emissions of Road Traffic

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    Ultrafine particles (<100 nm) in urban air are a serious health hazard not yet fully understood. Therefore, particle number concentration monitoring was recently included in the WHO air quality guidelines. At present, e.g., the EU regulates particle number only regarding the emissions of solid particles larger than 23 nm emitted by vehicles. The aim of this study was to examine the non-volatile fraction of sub-23 nm particles in a trafficinfluenced urban environment. We measured the number concentration of particles larger than 1.4, 3, 10, and 23 nm in May 2018. Volatile compounds were thermally removed in the sampling line and the line losses were carefully determined. According to our results, the sub-23 nm particles dominated the non-volatile number concentrations. Additionally, based on the determined particle number emission factors, the traffic emissions of non-volatile sub-10 nm particles can be even 3 times higher than those of particles larger than 10 nm. Yet, only a fraction of urban sub-10 nm particles consisted of non-volatiles. Thus, while the results highlight the role of ultrafine particles in the traffic-influenced urban air, a careful consideration is needed in terms of future particle number standards to cover the varying factors affecting measured concentrations

    Particle emissions of Euro VI, EEV and retrofitted EEV city buses in real traffic

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    Emission control technologies used in Euro VI buses are effectively reducing soot and NO x emissions in real operation, but small sub-3 nm particles exist in variable concentrations in the exhaust of Euro VI, EEV and retrofitted EEV buses.publishedVersionPeer reviewe

    Physical and Chemical Characterization of Real-World Particle Number and Mass Emissions from City Buses in Finland

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    Exhaust emissions of 23 individual city buses at Euro III, Euro IV and EEV (Enhanced Environmentally Friendly Vehicle) emission levels were measured by the chasing method under real-world conditions at a depot area and on the normal route of bus line 24 in Helsinki. The buses represented different technologies from the viewpoint of engines, exhaust after-treatment systems (ATS) and fuels. Some of the EEV buses were fueled by diesel, diesel-electric, ethanol (RED95) and compressed natural gas (CNG). At the depot area the emission factors were in the range of 0.3-21 × 10<sup>14</sup> # (kg fuel)<sup>−1</sup>, 6–40 g (kg fuel)<sup>−1</sup>, 0.004–0.88 g (kg fuel)<sup>−1</sup>, 0.004–0.56 g (kg fuel)<sup>−1</sup>, 0.01–1.2 g (kg fuel)<sup>−1</sup>, for particle number (EF<sub>N</sub>), nitrogen oxides (EF<sub>NOx</sub>), black carbon (EF<sub>BC</sub>), organics (EF<sub>Org</sub>), and particle mass (EF<sub>PM1</sub>), respectively. The highest particulate emissions were observed from the Euro III and Euro IV buses and the lowest from the ethanol and CNG-fueled buses, which emitted BC only during acceleration. The organics emitted from the CNG-fueled buses were clearly less oxidized compared to the other bus types. The bus line experiments showed that lowest emissions were obtained from the ethanol-fueled buses whereas large variation existed between individual buses of the same type indicating that the operating conditions by drivers had large effect on the emissions

    Traffic is a major source of atmospheric nanocluster aerosol

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    In densely populated areas, traffic is a significant source of atmospheric aerosol particles. Owing to their small size and complicated chemical and physical characteristics, atmospheric particles resulting from traffic emissions pose a significant risk to human health and also contribute to anthropogenic forcing of climate. Previous research has established that vehicles directly emit primary aerosol particles and also contribute to secondary aerosol particle formation by emitting aerosol precursors. Here, we extend the urban atmospheric aerosol characterization to cover nanocluster aerosol (NCA) particles and show that a major fraction of particles emitted by road transportation are in a previously unmeasured size range of 1.3–3.0 nm. For instance, in a semiurban roadside environment, the NCA represented 20–54% of the total particle concentration in ambient air. The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. The emission factors of NCA for traffic were 2.4·1015 (kgfuel)−1 in a roadside environment, 2.6·1015 (kgfuel)−1 in a street canyon, and 2.9·1015 (kgfuel)−1 in an on-road study throughout Europe. Interestingly, these emissions were not associated with all vehicles. In engine laboratory experiments, the emission factor of exhaust NCA varied from a relatively low value of 1.6·1012 (kgfuel)−1 to a high value of 4.3·1015 (kgfuel)−1. These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds.acceptedVersionacceptedVersionPeer reviewe
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