Customer-end inverter in an LVDC distribution network

An AC-based low-voltage distribution network can in some cases be replaced with a low-voltage direct current (LVDC) network. With a higher DC voltage, the transmission capacity increases compared with the AC system with the same cable cross-sectional area. The DC link feeds an inverter that converts the DC voltage to a 230 V single-phase or 400 V three-phase AC voltage. Because the three-phase voltage is not necessarily needed in most residential applications, this paper presents two single-phase inverter topologies. Inverter modulation and its suitability for this kind of an application is discussed. The inverter efficiency and its requirements are also discussed in brief, yet more precise analyses are left for future studies. The conclusion is that a half-bridge topology is not suitable for this application, and therefore, a full-bridge inverter should be used instead.reviewe

An LVDC distribution system concept

An LVDC distribution system is a new innovation in a field of electricity distribution. This paper presents the basic principles to use power electronics devices in electricity distribution systems. Recent technological and economical developments in power electronic components enable to apply power electronics in LV network. This development makes an LVDC distribution system concept establishment possible. In this respect the occurring progression connects power electronics and distribution system development strongly together. The LVDC distribution system basic concept concentrates at DC/AC interface focusing on implementation of customer-end inverter. The previously made analyses have shown that presented LVDC distribution system has existing techno-economical potential in electricity distribution networks.reviewe

Puun alkuperän hallinta Walki Oy:ssä

Pakkausmateriaalien loppukäyttäjien ympäristötietoisuus on kasvanut, jolloin vaatimukset ympäristön huomioivasta kestävästä tuotannosta ovat asettaneet vaatimuksia myös sille, että myös pakkausmateriaaleihin käytettävien paperien alkuperä on oltava selvillä. Tässä työssä on luotu puun alkuperän hallinta järjestelmä Walki Oy Pietarsaaren tehtaalle, jolla voidaan osoittaa, että myös Walki Oy, johtavana pakkausmateriaalien valmistajana, toimii vastuullisesti myös näissä asioissa. Aikaan saatu hallintajärjestelmä voidaan tarvittaessa ottaa käyttöön myös muilla Walki Groupin tehtailla. Työssä perehdytään metsien sertifiointiin ja puun alkuperän sertifiointiin. Myös integroitu hallintajärjestelmä ja käytettävät tuotannon ohjausjärjestelmät esitellään, jotta saadaan parempi kuvaus hallintajärjestelmän asettumisesta nykyiseen laatu- ja ympäristöjärjestelmään. Työn keskiosassa käsitellään tutkimusmenetelmät ja esitellään sertifiointi prosessi käytännössä.Työn loppuvaiheessa perehdytään puun alkuperän hallintajärjestelmän rakentamiseen ja saavutettuihin tuloksiin, yrityksen asettamien rajauksien mukaan

A semi-empirical model of boreal-forest gross primary production, evapotranspiration, and soil water — calibration and sensitivity analysis

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Laminin-511 and laminin-521-based matrices for efficient hepatic specification of human pluripotent stem cells

Human pluripotent stem cells (hPSCs) have gained a solid foothold in basic research and drug industry as they can be used in vitro to study human development and have potential to offer limitless supply of various somatic cell types needed in drug development. Although the hepatic differentiation of hPSCs has been extensively studied, only a little attention has been paid to the role of the extracellular matrix. In this study we used laminin-511, laminin-521, and fibronectin, found in human liver progenitor cells, as culture matrices for hPSC-derived definitive endoderm cells. We observed that laminin-511 and laminin-521 either alone or in combination support the hepatic specification and that fibronectin is not a vital matrix protein for the hPSC-derived definitive endoderm cells. The expression of the laminin-511/521-specific integrins increased during the definitive endoderm induction and hepatic specification. The hepatic cells differentiated on laminin matrices showed the upregulation of liver-specific markers both at mRNA and protein levels, secreted human albumin, stored glycogen, and exhibited cytochrome P450 enzyme activity and inducibility. Altogether, we found that laminin-511 and laminin-521 can be used as stage-specific matrices to guide the hepatic specification of hPSC-derived definitive endoderm cells. 2016 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND licensePeer reviewe

Digital photography for assessing the link between vegetation phenology and CO2 exchange in two contrasting northern ecosystems

Digital repeat photography has become a widely used tool for assessing the annual course of vegetation phenology of different ecosystems. By using the green chromatic coordinate (GCC) as a greenness measure, we examined the feasibility of digital repeat photography for assessing the vegetation phenology in two contrasting high-latitude ecosystems. Ecosystem-atmosphere CO2 fluxes and various meteorological variables were continuously measured at both sites. While the seasonal changes in GCC were more obvious for the ecosystem that is dominated by annual plants (open wetland), clear seasonal patterns were also observed for the evergreen ecosystem (coniferous forest). Daily and seasonal time periods with sufficient solar radiation were determined based on images of a grey reference plate. The variability in cloudiness had only a minor effect on GCC, and GCC did not depend on the sun angle and direction either. The daily GCC of wetland correlated well with the daily photosynthetic capacity estimated from the CO2 flux measurements. At the forest site, the correlation was high in 2015 but there were discernible deviations during the course of the summer of 2014. The year-to-year differences were most likely generated by meteorological conditions, with higher temperatures coinciding with higher GCCs. In addition to depicting the seasonal course of ecosystem functioning, GCC was shown to respond to environmental changes on a timescale of days. Overall, monitoring of phenological variations with digital images provides a powerful tool for linking gross primary production and phenology.Peer reviewe

Networked web-cameras monitor congruent seasonal development of birches with phenological field observations

Ecosystems' potential to provide services, e.g. to sequester carbon, is largely driven by the phonological cycle of vegetation. Timing of phenological events is required for understanding and predicting the influence of climate change on ecosystems and to support analyses of ecosystem functioning. Analyses of conventional camera time series mounted near vegetation has been suggested as a means of monitoring phenological events and supporting wider monitoring of phenological cycle of biomes that is frequently done with satellite earth observation (EO). Especially in the boreal biome, sparsely scattered deciduous trees amongst conifer-dominant forests pose a problem for EO techniques as species phenological signal mix, and render EO data difficult to interpret. Therefore, deriving phonological information from on the ground measurements would provide valuable reference data for earth observed phonology products in a larger scale. Keeping this in mind, we established a network of digital cameras for automated monitoring of phenological activity of vegetation in the boreal ecosystems of Finland. Cameras were mounted at 14 sites, each site having 1-3 cameras. In this study, we used data from 12 sites to investigate how well networked cameras can detect the phenological development of birches (Betula spp.) along a latitudinal gradient. Birches typically appear in small quantities within the dominant species. We tested whether the small, scattered birch image elements allow a reliable extraction of colour indices and the temporal changes therein. We compared automatically derived phenological dates from these birch image elements both to visually determined dates from the same image time series and to independent observations recorded in the phenological monitoring network covering the same region, Automatically extracted season start dates, which were based on the change of green colour fraction in spring, corresponded well with the visually interpreted start of the season, and also to the budburst dates observed in the field. Red colour fraction turned out to be superior to the green colour-based indices in predicting leaf yellowing and fall. The latitudinal gradients derived using automated phenological date extraction corresponded well with the gradients estimated from the phenological field observations. We conclude that small and scattered birch image elements allow reliable extraction of key phonological dates for the season start and end of deciduous species studied here, thus providing important species-specific data for model validation and for explaining the temporal variation in EO phenology products.Peer reviewe

Hallitusohjelman mukaisten sosiaaliturvan leikkausten vaikutukset vuoteen 2027

Petteri Orpon hallitusohjelma sisältää lukuisia sosiaaliturvaan kohdistuvia muutoksia. Hallitus hakee säästöjä niin työttömyysturvasta, asumistuesta, kuntoutusetuuksista kuin toimeentulotuestakin. Näiden lisäksi osaan sosiaaliturvaetuuksista ehdotetaan indeksitarkastuksen tekemättä jättämistä vuosille 2024 2027. Kaavaillut muutokset ovat poikkeuksellisen suuria aikaisempiin hallituskausiin verrattuna. Tässä työpaperissa arvioidaan hallituksen syksyllä 2023 eduskuntaan tuomien, sosiaaliturvaa käsittelevien lakiesitysten yhteisvaikutuksia kotitalouksien taloudelliseen asemaan. Laskelmat on toteutettu SISU-mikrosimulointimallilla. Hallituksen esityksiä ja tehtyjä laskelmia peilataan myös perus- ja ihmisoikeusvelvoitteiden sosiaaliturvalle asetettuihin reunaehtoihin. Laskelmat osoittavat hallituksen toimien lisäävän pienituloisuutta merkittävästi. Vaikutukset kohdistuvat voimakkaimmin jo valmiiksi pienituloisille väestöryhmille kuten työttömille, opiskelijoille ja muille heikommassa asemassa oleville, mikä lisää eriarvoisuutta eri väestöryhmien välillä