101,706 research outputs found
Suomalaisten puunostajien asennoituminen metsän tietokonevisualisoinnin toteuttamiseen
No full textTutkimusselosteSeloste artikkelista: Palander, T., Turunen, K. & Laukkanen, S. 2003. Attitude of Finnish timber buyers towards implementation of a forest computer visualisation. Silva Fennica 37(2): 269–281
The Redistribution of Efficiency Gains: Transfers or Tariffs?
No full textThis paper is concerned with some theoretical issues in cooperative multilateral trade policy reform. The focus of the paper is on the structure of the policy reform problem, particularly as it applies to piecemeal policy reform, and on the similarity in roles that can be played by income transfers on the one hand and tariffs reforms on the other as redistributive policy instruments. More specifically, the paper is concerned with the mechanism by which efficiency gains arising out of trade policy reforms can be distributed amongst countries to achieve a strict Pareto improvement in welfare. Traditionally, trade theorists have assumed the existence of lump sum income transfers to distribute efficiency gains. Turunen-Red and Woodland (2000) have shown that income transfers accompanying quota reforms can be replaced by suitable multilateral tariff reforms to achieve the same welfare outcome. In the current paper, we generalize this idea to deal with discrete policy reforms. And, we develop several applications to enhance understanding of the connection between tariffs and transfers. If lump sum transfers are not available policy instruments, the achievement of a strict Pareto improvement must depend on changes in distortionary taxes, such as domestic taxes or tariffs on trade. Our results show that, under a mild condition on the world trade matrix, it does not matter whether lump sum transfers are available. Transfers can be replaced by a carefully chosen set of tariffs to achieve the same welfare outcome. This ability to replace transfers by tariffs is a result of the structure of the model of international trade: the terms of trade effects for a country and a lump sum transfers are equivalent, and there are sufficient tariff instruments to enable countries to neutralize the domestic price effects of terms of trade movements.
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Uusia kontribuutioita VLF-radioaaltojen häiriöihin mitattuna korkeilla leveysasteilla
No full textAbstractThe Earth-ionosphere system behaves as a waveguide for the propagation of very low frequency (VLF) radio waves. If in this system the electrical conductivity of its boundaries is disturbed, the propagation of VLF waves is also disrupted, which is observed as phase and amplitude variations of VLF waves with respect to their quiescent levels. There is a diversity of physical phenomena that are able to alter significantly the conductivity of the upper boundary. These phenomena can have their origin at the Earth (e.g., lightning), in the solar system (e.g., solar flares) or even much farther away (e.g., galactic gamma-ray bursts). The aim of this thesis is to study short- and long-term VLF variations measured in Northern Finland (at the Sodankylä Geophysical Observatory) and their associations to different phenomena. The main results are as follows: [i] The minimum energy a solar flare should have in order to produce ionospheric disturbances depends on the solar cycle. This energy is understood as the ionospheric sensitivity and for daytime conditions its value lies in the range (1–12) × 10⁻⁷ J/m². [ii] The semiannual oscillation that appears in VLF measurements was determined to be related to geomagnetic activity variations. At the same time, it was found that the 27-day solar rotation oscillation is dominant during the declining phase of the solar cycle. [iii] The main characteristics of the observed VLF sunrise phase perturbation are derived from the shadowing of short wavelength solar UV radiation due to stratospheric ozone absorption when the Sun rises. [iv] VLF emissions with banded structure were observed in the 16–39 kHz frequency range, which are frequencies not usually used for the study of whistler mode VLF emissions coming from the magnetosphere. All these results are important since the VLF signals are related to variations of electron density in the ionospheric D-region, and thus have been used to identify the processes that influence the behavior of the upper atmosphere. The mentioned results can provide useful constraints on the long-term and short-term variability in coupled ion-neutral atmospheric models, thereby adding to our understanding of the response of the chemistry, dynamics and electrodynamics of the Earth’s ionosphere to solar and atmospheric forcing.Original papersOriginal papers are not included in the electronic version of the dissertation.Macotela, E. L., Raulin, J.-P., Manninen, J., Correia, E., Turunen, T., & Magalhães, A. (2017). Lower Ionosphere Sensitivity to Solar X-ray Flares Over a Complete Solar Cycle Evaluated From VLF Signal Measurements. Journal of Geophysical Research: Space Physics, 122(12), 12,370-12,377. https://doi.org/10.1002/2017ja024493Self-archived versionMacotela, E. L., Clilverd, M., Manninen, J., Moffat-Griffin, T., Newnham, D. A., Raita, T., & Rodger, C. J. (2019). D-Region High-Latitude Forcing Factors. Journal of Geophysical Research: Space Physics, 124(1), 765–781. https://doi.org/10.1029/2018ja026049Self-archived versionMacotela, E. L., Clilverd, M. A., Manninen, J., Thomson, N. R., Newnham, D. A., & Raita, T. (2019). The Effect of Ozone Shadowing on the D Region Ionosphere During Sunrise. Journal of Geophysical Research: Space Physics, 124(5), 3729–3742. https://doi.org/10.1029/2018ja026415Self-archived versionMacotela, E. L., Němec, F., Manninen, J., Santolík, O., Kolmašová, I., & Turunen, T. (2019). VLF Emissions With Banded Structure in the 16- to 39-kHz Frequency Range Measured by a High-Latitude Ground-Based Receiver. Geophysical Research Letters, 46(24), 14214–14222. https://doi.org/10.1029/2019gl086127Self-archived versionTiivistelmäMaa-ionosfäärijärjestelmä toimii aaltoputkena erittäin matalataajuisille (VLF) radioaalloille. Jos tässä järjestelmässä sen rajojen sähkönjohtavuus häiriintyy, myös VLF-aaltojen eteneminen häiriintyy, mikä havaitaan VLF-aaltojen vaihe- ja amplitudivaihteluina suhteessa niiden tasoon hiljaisina aikoina. On olemassa useita erilaisia fysikaalisia ilmiöitä, jotka pystyvät muuttamaan merkittävästi ylärajan johtavuutta. Nämä ilmiöt voivat olla peräisin maapallolta (esim. planetaariset aallot), aurinkokunnastamme (esim. auringon roihupurkaukset) tai jopa paljon kauempaa (esim. galaktiset gammapurkaukset). Tässä väitöskirjassa tutkijaan Pohjois-Suomessa (Sodankylän geofysiikan observatoriossa) mitattuja lyhyen ja pitkän aikavälin VLF-vaihteluita ja niiden yhteyksiä eri ilmiöihin. Tärkeimmät tulokset ovat seuraavat: [i] määritettiin, miten ionosfäärin päiväajan herkkyys ulkoisille häiriötekijöille riippuu auringon aktiivisuuden vaiheesta. Tämä tutkimus ymmärretään vähimmäisenergian suhteen, joka ulkoisella tapahtumalla, kuten auringon roihupurkauksella, tulisi olla, jotta se aiheuttaisi signaalin leviämiseen vaikuttavia ionosfäärisiä häiriöitä. [ii] VLF-mittauksissa esiintyvän vuotuisen vaihtelun havaittiin liittyvän mesofäärin lämpötilaan ja auringon Lyman-α-vuohon päivä- ja yöolosuhteissa. Puolivuosittaisen vaihtelun havaittiin liittyvän geomagneettisen aktiivisuuden muutoksiin. Samalla todettiin, että auringon 27 päivän pyörimisjaksoa vastaava värähtely on hallitseva auringon aktiivisuuden laskuvaiheessa. [iii] Auringonnousuvaiheen VLF-häiriöiden pääominaisuuksien havaittiin johtuvan lyhyen aallonpituuden auringon UV-vuon varjostumisesta D-alueen ionosfäärissä johtuen stratosfäärin otsonin absorptiosta auringon noustessa. [iv] VLF-aaltoja, joissa oli raitamainen rakenne, havaittiin taajuusalueella 16–39 kHz. Näitä taajuuksia ei yleensä käytetä magnetosfääristä tulevien vihellysmoodin VLF-aaltojen tutkimiseen. Tuloksemme ovat tärkeitä, koska VLF-signaalit liittyvät elektronitiheyden muutoksiin ionosfäärin D-alueella, ja siten niitä on käytetty tunnistamaan prosessit, jotka vaikuttavat ylemmän ilmakehän käyttäytymiseen. Mainitut tulokset voivat tarjota hyödyllisiä rajoja pitkä- ja lyhytaikaiseen vaihteluun ilmakehän yhdistettyissä ionineutraalimalleissa, mikä lisää ymmärrystämme Maan ionosfäärin kemiallisesta, dynaamisesta ja sähködynaamisesta vasteesta auringon ja ilmakehän pakotukseen.OsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Macotela, E. L., Raulin, J.-P., Manninen, J., Correia, E., Turunen, T., & Magalhães, A. (2017). Lower Ionosphere Sensitivity to Solar X-ray Flares Over a Complete Solar Cycle Evaluated From VLF Signal Measurements. Journal of Geophysical Research: Space Physics, 122(12), 12,370-12,377. https://doi.org/10.1002/2017ja024493Rinnakkaistallennettu versioMacotela, E. L., Clilverd, M., Manninen, J., Moffat-Griffin, T., Newnham, D. A., Raita, T., & Rodger, C. J. (2019). D-Region High-Latitude Forcing Factors. Journal of Geophysical Research: Space Physics, 124(1), 765–781. https://doi.org/10.1029/2018ja026049Rinnakkaistallennettu versioMacotela, E. L., Clilverd, M. A., Manninen, J., Thomson, N. R., Newnham, D. A., & Raita, T. (2019). The Effect of Ozone Shadowing on the D Region Ionosphere During Sunrise. Journal of Geophysical Research: Space Physics, 124(5), 3729–3742. https://doi.org/10.1029/2018ja026415Rinnakkaistallennettu versioMacotela, E. L., Němec, F., Manninen, J., Santolík, O., Kolmašová, I., & Turunen, T. (2019). VLF Emissions With Banded Structure in the 16- to 39-kHz Frequency Range Measured by a High-Latitude Ground-Based Receiver. Geophysical Research Letters, 46(24), 14214–14222. https://doi.org/10.1029/2019gl086127Rinnakkaistallennettu versioAcademic dissertation to be presented, with the assent of the Doctoral Training Committee of Technology and Natural Sciences of the University of Oulu for public discussion in the Polaria lecture hall of Sodankylä Geophysical Observatory on 23 April 2020 at 12 o’clock noon.Abstract
The Earth-ionosphere system behaves as a waveguide for the propagation of very low frequency (VLF) radio waves. If in this system the electrical conductivity of its boundaries is disturbed, the propagation of VLF waves is also disrupted, which is observed as phase and amplitude variations of VLF waves with respect to their quiescent levels. There is a diversity of physical phenomena that are able to alter significantly the conductivity of the upper boundary. These phenomena can have their origin at the Earth (e.g., lightning), in the solar system (e.g., solar flares) or even much farther away (e.g., galactic gamma-ray bursts). The aim of this thesis is to study short- and long-term VLF variations measured in Northern Finland (at the Sodankylä Geophysical Observatory) and their associations to different phenomena. The main results are as follows: [i] The minimum energy a solar flare should have in order to produce ionospheric disturbances depends on the solar cycle. This energy is understood as the ionospheric sensitivity and for daytime conditions its value lies in the range (1–12) × 10⁻⁷ J/m². [ii] The semiannual oscillation that appears in VLF measurements was determined to be related to geomagnetic activity variations. At the same time, it was found that the 27-day solar rotation oscillation is dominant during the declining phase of the solar cycle. [iii] The main characteristics of the observed VLF sunrise phase perturbation are derived from the shadowing of short wavelength solar UV radiation due to stratospheric ozone absorption when the Sun rises. [iv] VLF emissions with banded structure were observed in the 16–39 kHz frequency range, which are frequencies not usually used for the study of whistler mode VLF emissions coming from the magnetosphere. All these results are important since the VLF signals are related to variations of electron density in the ionospheric D-region, and thus have been used to identify the processes that influence the behavior of the upper atmosphere. The mentioned results can provide useful constraints on the long-term and short-term variability in coupled ion-neutral atmospheric models, thereby adding to our understanding of the response of the chemistry, dynamics and electrodynamics of the Earth’s ionosphere to solar and atmospheric forcing.Tiivistelmä
Maa-ionosfäärijärjestelmä toimii aaltoputkena erittäin matalataajuisille (VLF) radioaalloille. Jos tässä järjestelmässä sen rajojen sähkönjohtavuus häiriintyy, myös VLF-aaltojen eteneminen häiriintyy, mikä havaitaan VLF-aaltojen vaihe- ja amplitudivaihteluina suhteessa niiden tasoon hiljaisina aikoina. On olemassa useita erilaisia fysikaalisia ilmiöitä, jotka pystyvät muuttamaan merkittävästi ylärajan johtavuutta. Nämä ilmiöt voivat olla peräisin maapallolta (esim. planetaariset aallot), aurinkokunnastamme (esim. auringon roihupurkaukset) tai jopa paljon kauempaa (esim. galaktiset gammapurkaukset). Tässä väitöskirjassa tutkijaan Pohjois-Suomessa (Sodankylän geofysiikan observatoriossa) mitattuja lyhyen ja pitkän aikavälin VLF-vaihteluita ja niiden yhteyksiä eri ilmiöihin. Tärkeimmät tulokset ovat seuraavat: [i] määritettiin, miten ionosfäärin päiväajan herkkyys ulkoisille häiriötekijöille riippuu auringon aktiivisuuden vaiheesta. Tämä tutkimus ymmärretään vähimmäisenergian suhteen, joka ulkoisella tapahtumalla, kuten auringon roihupurkauksella, tulisi olla, jotta se aiheuttaisi signaalin leviämiseen vaikuttavia ionosfäärisiä häiriöitä. [ii] VLF-mittauksissa esiintyvän vuotuisen vaihtelun havaittiin liittyvän mesofäärin lämpötilaan ja auringon Lyman-α-vuohon päivä- ja yöolosuhteissa. Puolivuosittaisen vaihtelun havaittiin liittyvän geomagneettisen aktiivisuuden muutoksiin. Samalla todettiin, että auringon 27 päivän pyörimisjaksoa vastaava värähtely on hallitseva auringon aktiivisuuden laskuvaiheessa. [iii] Auringonnousuvaiheen VLF-häiriöiden pääominaisuuksien havaittiin johtuvan lyhyen aallonpituuden auringon UV-vuon varjostumisesta D-alueen ionosfäärissä johtuen stratosfäärin otsonin absorptiosta auringon noustessa. [iv] VLF-aaltoja, joissa oli raitamainen rakenne, havaittiin taajuusalueella 16–39 kHz. Näitä taajuuksia ei yleensä käytetä magnetosfääristä tulevien vihellysmoodin VLF-aaltojen tutkimiseen. Tuloksemme ovat tärkeitä, koska VLF-signaalit liittyvät elektronitiheyden muutoksiin ionosfäärin D-alueella, ja siten niitä on käytetty tunnistamaan prosessit, jotka vaikuttavat ylemmän ilmakehän käyttäytymiseen. Mainitut tulokset voivat tarjota hyödyllisiä rajoja pitkä- ja lyhytaikaiseen vaihteluun ilmakehän yhdistettyissä ionineutraalimalleissa, mikä lisää ymmärrystämme Maan ionosfäärin kemiallisesta, dynaamisesta ja sähködynaamisesta vasteesta auringon ja ilmakehän pakotukseen
Optimal Vaneless Diffuser Design For A High-End Centrifugal Compressor
No full textTurbochargers are widely used in the automotive industry to reduce engine emissions and to increase the power. Centrifugal compressors are an integral part of turbochargers. Centrifugal compressors comprises primarily of inducer, impeller, diffuser and volute. The diffuser has an important role in the isentropic efficiency of the compressor. Over the past few decades, researchers have been trying to increase the total-to-total compressor stage efficiency by altering the diffuser’s geometries. Many different methods have been adopted for this purpose, like pinching the diffuser walls, tilting the diffuser walls etc. Pinching increases the outer width of the diffuser while tilting provides an increased radial length. In the present study, both these methods have been used simultaneously. The primary benefit of doing so is to make the turbocharger compressor stage more compact in design, which is the current requirement of the automotive market. In order to investigate the effect of pinching and tilting of diffuser walls, a Computational Fluid Dynamics based solver has been used to predict the flow phenomena within the compressor, especially in the vaneless diffuser. Design of Experiments, using Taguchi’s method, has been incorporated in this study to statistically define the scope of the numerical work, and to obtain the optimal configuration of pinching and tilting that leads to maximum total-to-total compressor stage efficiency. The results depict that the compressor stage efficiency increases up to a tilt angle of 6.25º, after which it starts to decrease. Furthermore, the stage efficiency increases with increase of diffuser outlet width i.e., pinching the diffuser passage, however, this increasing trend has been observed up to an outlet width ratio of 1.23, after which the stage efficiency starts to decrease. Hence, the optimal diffuser model, based on the combined tilting and pinching results obtained, which leads to the maximum total-to-total compressor stage efficiency, has been identified and analysed
Method of Characteristics-Based Design and Numerical Simulation of a Micro-ORC Supersonic Turbine Nozzle Ring
No full textHandwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Pelevin’s Trinity in the novel “t”: author – protagonist – reader
No full textThe article attempts to interpret Pelevin's artistic strategy in the novel "T" by exploring its subject organization and addressing the key problems of the author, the protagonist, and the reader as they are seen by the researcher. The article analyzes the peculiarities of constructing the narrative reality in the novel "T", and goes on to discuss Pelevin's philosophic models of the development of the humankind, and the emergence of his new anthropology
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