37 resultados para Boost


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Julkisen sektorin organisaatioita on kritisoitu niiden tehottomuudesta palveluiden tuottajina ja kritiikki on lisännyt keskustelua julkisen ja yksityisen sektorin sopivasta suhteesta. Julkisen sektorin organisaatioissa tilanteeseen on herätty ja toiminnan tehostamiseen on alettu etsiä keinoja. New Public Management:in ja tulosjohtamisen ajatusmaailma ovat ottaneet jalansijaa julkisen sektorin johtamisessa ja samalla tuoneet mukanaan entistä tulospainotteisempaa ajattelutapaa. Helsingin kaupungin liikuntavirastolla siirryttiin bruttobudjetoinnista nettobudjetointiin vuoden 2013 alusta. Budjetointimenetelmän muutoksen taustalla vaikuttaa tavoite viraston toiminnan tehostamisesta. Tutkimus keskittyy selvittämään liikuntaviraston muutosprosessia ja uuden budjetointimenetelmän implementointia. Tutkimuksen tavoitteena on luoda työkalu helpottamaan nettobudjetoinnin implementointia. Tutkimuksen empiirinen aineisto kerättiin puolistrukturoitujen haastattelujen avulla, jotka suoritettiin joulukuun 2012 ja huhtikuun 2013 välillä. Empiiriseen aineistoon ja muutosjohtamisen teoriaan nojaten tutkimuksessa onnistuttiin luomaan liikuntavirastolle muutosprosessin vaihemalli, joka sisältää toimenpide-ehdotuksia muutoksen ja uuden budjetointimenetelmän implementoinnin helpottamiseksi.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Audiovahvistimet pohjautuvat yhä useammin D-luokan vahvistimiin niiden korkean hyötysuhteen takia. Tämä mahdollistaa pidemmän käyttöajan tai vastaavasti tehon lisäämisen kannettavissa audiolaitteissa. Kuitenkin, jotta akkukäyttöisestä audiolaitteesta saataisiin suurempaa tehoa, se vaatii yleensä korkeamman jännitteen kuin yksittäisen akun lähtöjännite on. Korkeampi jännite voidaan saavuttaa lisäämällä akkuja tai käyttämällä jännitettä nostavaa hakkuria. Hakkureissa syntyy kuitenkin kytkennästä johtuvaa värettä, mille D-luokan vahvistimet ovat alttiita. Tässä työssä tutkitaan boost- ja Čuk-hakkurin soveltuvuutta jännitteen nostoon akkukäyttöisessä audiolaitteessa. Käytännön sovelluksena toimii Porsas, josta halutaan saada 500 W teho. Työssä tutkitaan audiolaitteen asettamia ehtoja jännitelähteelle sekä hakkurien mitoittamista ehtojen mukaisesti. Työn tutkimustapana on kirjallisuustutkimus ja simulointi. Audiolaitteen jännitelähteeltä vaatima teho vaihtelee suuresti. Tämä tulee ottaa huomioon hakkurin komponenttien mitoituksessa. Lisäksi hakkurin lähtöjännitteen väre pyritään minimoimaan, koska sillä on suuri vaikutus vahvistimen toimintaan. Tulovirran väreen minimoinnilla on pidentävä vaikutus akun purkusykliin. Hakkurien laskennalliset komponenttien arvot sekä simuloinnit osoittavat, että hakkurit olisivat myös mahdollista tehdä käytännössä. Simulointien perusteella boost-hakkurin komponenttien arvot ovat pienempiä kuin Čuk-hakkurin. Boost-hakkurille löytyy myös valmiita ohjainpiirejä enemmän. Toisaalta Čuk-hakkurilla on mahdollista tehdä myös energiansäästötila. Hakkurien ohjaus ja jäähdytys vaatisivat jatkotutkimusta.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Switching power supplies are usually implemented with a control circuitry that uses constant clock frequency turning the power semiconductor switches on and off. A drawback of this customary operating principle is that the switching frequency and harmonic frequencies are present in both the conducted and radiated EMI spectrum of the power converter. Various variable-frequency techniques have been introduced during the last decade to overcome the EMC problem. The main objective of this study was to compare the EMI and steady-state performance of a switch mode power supply with different spread-spectrum/variable-frequency methods. Another goal was to find out suitable tools for the variable-frequency EMI analysis. This thesis can be divided into three main parts: Firstly, some aspects of spectral estimation and measurement are presented. Secondly, selected spread spectrum generation techniques are presented with simulations and background information. Finally, simulations and prototype measurements from the EMC and the steady-state performance are carried out in the last part of this work. Combination of the autocorrelation function, the Welch spectrum estimate and the spectrogram were used as a substitute for ordinary Fourier methods in the EMC analysis. It was also shown that the switching function can be used in preliminary EMC analysis of a SMPS and the spectrum and autocorrelation sequence of a switching function correlates with the final EMI spectrum. This work is based on numerous simulations and measurements made with the prototype. All these simulations and measurements are made with the boost DC/DC converter. Four different variable-frequency modulation techniques in six different configurations were analyzed and the EMI performance was compared to the constant frequency operation. Output voltage and input current waveforms were also analyzed in time domain to see the effect of the spread spectrum operation on these quantities. According to the results presented in this work, spread spectrum modulation can be utilized in power converter for EMI mitigation. The results from steady-state voltage measurements show, that the variable-frequency operation of the SMPS has effect on the voltage ripple, but the ripple measured from the prototype is still acceptable in some applications. Both current and voltage ripple can be controlled with proper main circuit and controller design.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Inclusion or Exclusion? Trade Union Strategies and Labor Migration This research identified and analyzed immigration-related strategies of the Finnish Construction Trade Union (FCTU) and the Service Union United (SUU); e.g. how the unions react to labor immigration, whether unions seek to include migrants in the unions, and what is migrants’ position in the unions. The two unions were chosen as the focus of the research because the workforce in the sectors they represent is migrant-dense. The study also analyzed the experiences that migrants who work in these sectors have with trade unions. The Estonian labor market situation –including the role of Estonian trade unions– was also examined as it has a considerable impact on the operating environment of the FCTU. The results of the study indicate that immigration is a contradictory issue for both unions. On the one hand, they strive to include migrants as trade union members and to defend migrants’ labor rights. On the other hand, they, together with their umbrella organization the Central Organisation of Finnish Trade Unions (SAK), seek to prevent labor immigration from outside the EU and EEA countries. They actively defend current labor immigration restrictions by drawing atten- tion to high unemployment figures and to the breaches of working conditions migrants encounter. In contrast, the employer organizations promote a more liberal state policy on labor immigration because they see it as a boost for business. Both the unions and the employer organizations ground their arguments on national interest. However, the position of the trade union movement is not uniform: unions belonging to the Confederation of Unions for Professionals and Managerial Staff in Finland (Akava) embrace more liberal labor immigration stances than the SAK. A key trade union strategy is to try to guarantee that migrants’ working condi- tions do not differ from those of the natives. The FCTU and the SUU inform migrants about Finnish collective agreements and trade union membership in the most common migrant languages. This is important for the unions because it is not in their interest that migrants’ working conditions are undercut. The interviewed migrants said that natives had more negotiating power with employers, which is often negatively portrayed in migrants’ working conditions. Migrants perceive that trade unions have an important role in protecting their working conditions. However, they stressed that migrants’ knowledge of unions is often very limited. The number of migrants in both two unions studied here is increasing. Espe- cially in the SUU, a considerable proportion of the new members are migrants. The FCTU is in a more challenging situation than the SUU because migrant construc- tion workers often work only for short periods in Finland and are consequently not interested in becoming union members. The unions’ strategies partly differ: the FCTU was the first Finnish trade union to establish a trade union branch/lo- cal for migrant members. The goal is to facilitate migrants’ inclusion in the union and to highlight the specific problems they face. The SUU, for its part, insists that such a special strategy would exclude migrants within the union organization. Despite the unions’ strategies, migrants are still underrepresented as union members and officials, which some of the interviewed migrants saw as a problem. Immigrants’ perception of trade unions was pragmatic: they had joined unions when membership yielded concrete benefits. In spite of the unions’ strategies, migrants –and temporary migrants– encoun- ter specific problems in terms of working conditions. Both unions demand more state intervention to protect migrants’ labor rights because overseeing working conditions consumes union resources. However, without the unions’ intervention, these problems would be more common than is currently the case. For instance, some of the interviewed migrants had received trade union assistance in claim- ing unpaid wages. The study demonstrated with the help of building on Walter Korpi’s power resources theory, that immigration is a power resource issue for the unions: suc- cessful immigration-related strategies strengthen unions –and vice versa. The research also showed how the unions’ operating environments constrain and enable their immigration-related strategies. This study has illuminated a previously ignored dimension: the immigrant- inclusive strategies of the Finnish trade unions. The research material consists of 78 qualitative interviews, observation in trade union events, and trade unions’ and employer organizations’ public state- ments.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In oxygenic photosynthesis, the highly oxidizing reactions of water splitting produce reactive oxygen species (ROS) and other radicals that could damage the photosynthetic apparatus and affect cell viability. Under particular environmental conditions, more electrons are produced in water oxidation than can be harmlessly used by photochemical processes for the reduction of metabolic electron sinks. In these circumstances, the excess of electrons can be delivered, for instance, to O2, resulting in the production of ROS. To prevent detrimental reactions, a diversified assortment of photoprotection mechanisms has evolved in oxygenic photosynthetic organisms. In this thesis, I focus on the role of alternative electron transfer routes in photoprotection of the cyanobacterium Synechocystis sp. PCC 6803. Firstly, I discovered a novel subunit of the NDH-1 complex, NdhS, which is necessary for cyclic electron transfer around Photosystem I, and provides tolerance to high light intensities. Cyclic electron transfer is important in modulating the ATP/NADPH ratio under stressful environmental conditions. The NdhS subunit is conserved in many oxygenic phototrophs, such as cyanobacteria and higher plants. NdhS has been shown to link linear electron transfer to cyclic electron transfer by forming a bridge for electrons accumulating in the Ferredoxin pool to reach the NDH-1 complexes. Secondly, I thoroughly investigated the role of the entire flv4-2 operon in the photoprotection of Photosystem II under air level CO2 conditions and varying light intensities. The operon encodes three proteins: two flavodiiron proteins Flv2 and Flv4 and a small Sll0218 protein. Flv2 and Flv4 are involved in a novel electron transport pathway diverting electrons from the QB pocket of Photosystem II to electron acceptors, which still remain unknown. In my work, it is shown that the flv4-2 operon-encoded proteins safeguard Photosystem II activity by sequestering electrons and maintaining the oxidized state of the PQ pool. Further, Flv2/Flv4 was shown to boost Photosystem II activity by accelerating forward electron flow, triggered by an increased redox potential of QB. The Sll0218 protein was shown to be differentially regulated as compared to Flv2 and Flv4. Sll0218 appeared to be essential for Photosystem II accumulation and was assigned a stabilizing role for Photosystem II assembly/repair. It was also shown to be responsible for optimized light-harvesting. Thus, Sll0218 and Flv2/Flv4 cooperate to protect and enhance Photosystem II activity. Sll0218 ensures an increased number of active Photosystem II centers that efficiently capture light energy from antennae, whilst the Flv2/Flv4 heterodimer provides a higher electron sink availability, in turn, promoting a safer and enhanced activity of Photosystem II. This intertwined function was shown to result in lowered singlet oxygen production. The flv4-2 operon-encoded photoprotective mechanism disperses excess excitation pressure in a complimentary manner with the Orange Carotenoid Protein-mediated non-photochemical quenching. Bioinformatics analyses provided evidence for the loss of the flv4-2 operon in the genomes of cyanobacteria that have developed a stress inducible D1 form. However, the occurrence of various mechanisms, which dissipate excitation pressure at the acceptor side of Photosystem II was revealed in evolutionarily distant clades of organisms, i.e. cyanobacteria, algae and plants.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coal slurry was of vital interest during the last century due to its potential as an alternative fuel where liquid fuels were necessary. Recently, environmental impacts of the traditional fuels, similarities of bio-coal to that of coal, and huge bio-coal supply has attracted the attention to prepare bio-coal slurries as a new fuel. Rudolf Diesel who invented the diesel engine on 1895 was of the opinion that diesel engines are capable to use different kinds of fuels due to the special design. He tried some kind of vegetable oil to operate on his IC engine. Recently, due to high energy density and more environmentally friendly fuel, researchers believe that bio-coal slurries could act as a new alternative fuel in large diesel engines. Loads of research on different kinds of bio-coal slurry were done by the other researchers worldwide and a lot of progress to boost slurry’s quality were achieved recently. The present study aims to achieve the ideal condition of different factors affecting on the quality of bio-coal slurry. One charcoal sample and two kinds of torrefied wood were used to investigate and compare the reaction of various factors. The results show a great gap between the quality of slurries made of different samples and more researches are necessary to fully understand the impact of the different parameter and improving the quality.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The role of the public export promotion in Finland needed more research. The part of the public sector export promotion in the overall export is significant. In an ever more global world not only the companies but also the counties compete against each other and the governments have an interest to boost their economy as much as they are able to. Every industrialized country has export promotion services in some form or another. In the 21st century the tendency has been the bundling of the services and this has also been done in Finland with Team Finland. The role and the efficiency of the services provided deserve more research. The research question of this study is: What is the role of the public export promotion services in Finland? The question is researched primary by expert interviews conducted for this study. The situation in Southwest Finland is studied from the viewpoint of the companies of the region by conducting a survey aimed to the successfully internationalized companies of the region and asking them on their views on the impact and role of public export services in their internationalization. The theory base is formed out of various export promotion studies, studies monitoring the effects of the promotion and theories of the internationalization process of companies. The primary material for the study are the three expert interviews conducted and the answers to the survey conducted. The research method in the first part is a constructive qualitative research. The research approach in the second part, where the views of the companies in Southwest Finland are studied, is quantitative. The study findings from the expert interviews: the aligning of the public export promotion done in Finland to the previous research and the addition of the role of the public sector in classical frameworks. The study findings from the survey: the utilizing of the public export promotion services is heavily delayed and the internationalizing companies start to utilize the services very late in their internationalization process, the average being 10,3 years from the beginning of the internationalization. Another central finding from the survey is that the successfully internationalized companies see the public export promotion services generally as highly beneficial but in the light of the answers the effect on their own company is not as significant. Concluding can be stated that the public export promotion is seen as beneficial, but the monitoring of the efficiency is complicated in the case of services. Getting the companies to start utilizing the services earlier in their internationalization needs attention from the service providers. By communicating the achieved results and benefits better to the potential users of the services the internationalization process of the companies could be accelerated