1000 resultados para 323-U1340
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1816/11/18 (Numéro 323).
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Invocatio: I.N.J.C.
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Low-cost tungsten monometallic catalysts containing variable amounts of metal (4.5, 7.1 and 8.5%W) were prepared by impregnating alumina with ammonium metatungstate as an inexpensive precursor. The catalysts were characterized using ICP, XPS, XRD, TPR and hydrogen chemisorption. These techniques revealed mainly WO3-Al2O3 (W6+) species on the surface. The effects of the content of W nanoparticles and reaction temperature on activity and selectivity for the partial hydrogenation of 3-hexyne, a non-terminal alkyne, were assessed under moderate conditions of temperature and pressure. The monometallic catalysts prepared were found to be active and stereoselective for the production of (Z )-3-hexene, had the following order: 7.1WN/A > 8.5 WN/A ≥ 4.5 WN/A. Additionally, the performance of the synthesized xWN/A catalysts exhibited high sensitivity to temperature variation. In all cases, the maximum 3-hexyne total conversion and selectivity was achieved at 323 K. The performance of the catalysts was considered to be a consequence of two phenomena: a) the electronic effects, related to the high charge of W (+6), causing an intensive dipole moment in the hydrogen molecule (van der Waals forces) and leading to heterolytic bond rupture; the H+ and H- species generated approach a 3-hexyne adsorbate molecule and cause heterolytic rupture of the C≡C bond into C- = C+; and b) steric effects related to the high concentration of WO3 on 8.5WN/A that block the Al2O3 support. Catalyst deactivation was detected, starting at about 50 min of reaction time. Electrodeficient W6+ species are responsible for the formation of green oil at the surface level, blocking pores and active sites of the catalyst, particularly at low reaction temperatures (293 and 303 K). The resulting best catalyst, 7.1WN/A, has low fabrication cost and high selectivity for (Z )-3-hexene (94%) at 323 K. This selectivity is comparable to that of the classical and more expensive industrial Lindlar catalyst (5 wt% Pd). The alumina supported tungsten catalysts are low-cost potential replacements for the Lindlar industrial catalyst. These catalysts could also be used for preparing bimetallic W-Pd catalysts for selective hydrogenation of terminal and non-terminal alkynes.
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A novel heteronuclear 3d-4f compound having formula NdCu3L3·13H2O (where H3L = Schiff base derived from 5-bromosalicylaldehyde and glycylglycine and L³ = C11H8 N2O4Br) was obtained. It was characterized by elemental and thermal analyses and magnetic measurements. The Cu(II)-Nd(III) compound is stable up to 323 K. During dehydration process the water molecules are lost in two stages. The magnetic susceptibility data for this complex change with temperature according to the Curie-Weiss law with theta = -35 K. The magnetic moment values decrease from 5.00µB at 303 K to 4.38µB at 76 K.
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Sustainability is the aim of forest management and forest regulation in many countries. Accordingly, forest management has been steered towards more environmentally friendly methods and new regulatory instruments have been introduced. At the same time, wood trade and forest industry have become a global business. Even if the importance of national forest legislation has not decreased, it has been widely acknowledged that national regulation of forest management is no longer sufficient. The movement of goods does not acknowledge boundaries, even though most negative environmental and social consequences stay in the country of origin of wood and other raw materials. As a partial solution to this dilemma, different kinds of regulations have been developed. Various forest certification schemes and wood trade regulation in the EU (995/2010) are examples of efforts to prevent illegal logging and unsustainable forestry. The Finland-based forest industry is to a varying extent dependent on wood trade from Russia. Especially in the 1990‟s, ethical questions concerning import of wood from Russian old growth forests near the Finnish border were widely discussed. Consequently, forest industry enterprises have developed systems to trace the origin of wood and to buy certified wood from Russia. The aim of the research has been to evaluate Finnish and Russian forest regulations in order to investigate what kind of forest management these regulations enhance, and to what extent ecologically sustainable forest management has been integrated into different forms of regulation. I have examined Finnish and Russian forest regulation in four separate articles based on the topics of the Russian Forest Code, forest certification and other voluntary forest protection measures in Russia, Finnish forest certification and Finnish forest legislation. One objective has been to analyse the roles voluntary forest certification plays in promoting sustainable forest management in different countries. In my research, I have mainly concentrated on ecological sustainability and protection of biodiversity, although other aspects of sustainable forest management have been touched upon in different articles. In the following I shall conclude the findings of my research. When the current Russian Forest Code (2006) was being adopted, the main emphasis was not on ecological issues, but on reorganizing forest governance. The role of ecological requirements was even slightly diminished during the legislative reform. There are, nevertheless, still stipulations aiming at ecological sustainability, such as the division of forests into different forest management categories and various protection zones. In 2000, FSC forest certification arrived in Russia, at present covering already 28 million hectares of forests. The PEFC scheme is now in use as well, but to a much lesser extent. If properly implemented, Russian forest certification schemes clearly improve the level of ecological and social sustainability of forestry in Russia. Certification criteria, however, are partly in conflict with the Russian forest legislation and certified enterprises have been forced to pay fines or to negotiate with forest authorities. This clearly indicates that even if Russian forest legislation has otherwise been liberalized to a certain extent, some significant paternalism still exists. Voluntary, hands-on biodiversity protection measures are not valued, and they are not part of the official protection policies as in many other countries. However, there have been some regional solutions to this dilemma. In the Republic of Karelia forest authorities have approved a set of forest biodiversity protection rules created by a local NGO and a forest industry enterprise. By following these local rules, an enterprise can avoid fines for protection measures. The current Finnish Forest Act was adopted in 1996. It brought forest legislation into a new era as some ecological aspects were integrated into forest legislation. The various soft-law forest management recommendations further increased the level of biodiversity protection. My evaluation of the overall legitimacy of the Finnish forest legislation and forest management paradigm revealed, however, several problematic issues. As part of this study I analysed the history of the current forest management paradigm. This analysis revealed the path dependency which still hinders the protection of biodiversity and clearly decreases the general legitimacy of forest management. Due to several historical reasons only even-structured forest management based on clear cuts has for decades been officially approved in Finland. Due to increasing demands of forest owners the legislation is finally being revised. Yet, the official approval of uneven-structured forest management would not be enough to fully improve ecological, social and cultural legitimacy. The latest ecological theories and knowledge of endangered species should be taken into account in the on-going reform of forest legislation as well as the modernisation. Forest legislation is one of the very few spheres of Finnish environmental legislation where openness and participation are still considered a threat. The first Finnish forest certification scheme, PEFC, was established in 2000. It now covers more than 20 million hectares, about 95% of the forests in Finland. PEFC Finland does not require a higher level of biodiversity protection than the recommendations by Tapio (the Development Centre for Forestry), but certification has unified forest management practices and requires more protection measures than mere forest legislation. The study suggests that in Finland PEFC has not functioned as an instrument which would substantially improve the level of forest management. Rather it has supported the status quo of the forest sector. While the ecological and social responsibility of Finland-based forest corporations was one impetus for this research, I want to conclude that there are problems related to forest legislation and non-state regulation in both Finland and Russia. If an enterprise buying wood from Russia buys only certified wood, and carefully avoids wood coming from high conservation value forests that are either ecologically or socially valuable, it can be claimed to be as sustainably produced as in Finland. However, there must be continuous scrutiny of the circumstances. In Russia, the level of the compliance of certification criteria varies considerably, and there are vast unprotected invaluable forest areas. The utilisation of these areas should not be based on short-sighted decisions or lack of consensus among stakeholders.
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Butia odorata é uma palmeira nativa do Rio Grande do Sul, Brasil, cujos frutos são utilizados na alimentação humana. O objetivo deste estudo foi testar a emergência de plântulas de B. odorata em casa de vegetação a partir de sementes e diásporos submetidos a diferentes procedimentos de superação de dormência. A escarificação através da abertura da cavidade embrionária das sementes permitiu emergência de 72%, com tempo médio de 56 dias. A imersão dos diásporos em água por 18 h antes da semeadura favoreceu a emergência, porém o tempo médio atrasou para 323 dias. Sementes isoladas do endocarpo, porém não escarificadas, apresentaram 38% de emergência, com tempo médio de 319 dias. A emergência a partir de diásporos submetidos a 40 ºC por três semanas antes da semeadura não diferiu da emergência de sementes isoladas do endocarpo; no entanto, o tempo médio foi reduzido de 319 para 206 dias. A abertura da cavidade embrionária possibilitou o maior percentual de emergência de plântulas e menor tempo médio de emergência.
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Under organic management in Seropédica-RJ, Brazil, using a weighing lysimeter, the crop coefficients (kc), the maximum evapotranspiration and the productivity of eggplant cultivation under two cropping systems (no tillage with straw plus soil with conventional preparation) were determined. A whole randomized layout with two treatments (no tillage and conventional) and five replicates during 134 days of cultivation were adopted. There were no significant differences in the eggplant cultivation in the two cropping systems, with a maximum commercial productivity obtained from 47.42 Mg ha-1 for the no-tillage system, and 47.91 Mg ha-1 for the conventional tillage. The accumulated ETc was 285.15 and 323.44 mm for the no-tillage and conventional, respectively. The crop coefficients value for the phases: 1 - transplanting, flowering, 2 - flowering-fruiting, 3 - fruit- first harvesting, 4- first harvesting of the final crop cycle was 0.83, 0.77, 0.90 and 0.97 in no-tillage system for the respective phases and for the conventional one 0.81, 1.14, 1.17 and 1.05 for the same steps described above.
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1868/03/09 (Numéro 323).
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Ilmanlaatua on seurattu Pohjois-Karjalan alueen kunnissa 1980-luvulta lähtien käyttäen ilmentäjinä havupuita ja niiden rungoilla kasvavia jäkäliä. Vuonna 1998 seuranta toteutettiin ensimmäisen kerran koko maakunnan laajuisena. Vuonna 2010 ilmanlaatua arvioitiin männyn epifyyttijäkälien esiintymisen ja kunnon sekä sammalten ja neulasten alkuainepitoisuuksien perusteella koko Pohjois-Karjalan maakunnan alueella. Tutkimusalueen päästömäärät ovat laskeneet selvästi 1980- ja 1990-luvuilta 2000-luvulle tultaessa, mutta 2000-luvulla etenkin rikkidioksidien ja hiukkasten päästökehitys on ollut aaltomaista. Myös liikenteen rikkidioksidin, typen oksidien ja hiukkasten päästöt ovat vähentyneet selvästi tarkasteluajanjaksolla. Ilmasta mitattujen epäpuhtauksien pitoisuudet ovat pääasiassa laskeneet 2000-luvulle tultaessa verrattuna 1980- ja 1990-lukuihin. Tutkimusalueen suurimmat päästölähteet sijaitsevat Joensuussa, Lieksassa ja Kiteellä. Ilman epäpuhtauksien vaikutukset ilmanlaatua kuvaaviin jäkälämuuttujiin olivat koko Pohjois-Karjalan maakunnan mittakaavassa lieviä ja erityisesti taustaalueilla vaikutukset olivat hyvin vähäisiä. Päästölähteiden ympäristössä vaikutukset olivat selvempiä, mutta laajuudeltaan melko pieniä. Terveintä sormipaisukarvetta tutkimusalueella kasvoi Kesälahdella, paikoin Kiteellä, Joensuun kaupungin alueella Tuupovaarassa ja Kiihtelysvaarassa, Ilomantsissa sekä Valtimon ja Nurmeksen pohjoisosissa. Vaurioituneinta sormipaisukarve oli Joensuun keskustaajamasta Hammaslahteen ulottuvalla vyöhykkeellä, Juuan kunnan keskiosassa ja Nurmeksen keskustaajamasta Valtimon kunnan eteläosaan ulottuvalla vyöhykkeellä. Tutkimusalueen pohjoisosissa jäkälälajisto oli laajalti luonnontilaista ja etelä- ja keskiosassa lievästi köyhtynyttä. Monipuolisin ja luonnontilaisin jäkäläyhteisö tutkimusalueella oli Kesälahden, Kontiolahden ja Valtimon kuntien alueella ja köyhtynein puolestaan Joensuun, Kiteen ja Rääkkylän alueella. Korkeimmat sammalten alkuainepitoisuudet tutkimusalueella määritettiin päästölähteiden läheisyydestä. Tilastollisten analyysien perusteella tutkimusalueelta löydettiin merkittävimmät raskasmetallien ja muiden alkuaineiden päästölähteet, joita olivat lämpölaitokset sekä kaivokset ja kaivostuotteiden jatkojalostuslaitokset. Tulosten perusteella sammalten raskasmetallipitoisuudet Pohjois-Karjalassa edustavat suhteellisen puhtaan tausta-alueen pitoisuuksia. Kuusen harsuuntuminen oli Pohjois-Karjalassa tilastollisesti merkitsevästi vähäisempää kuin muualla maan eteläosissa. Männyn harsuuntuminen ei poikennut muun Etelä-Suomen arvoista. Erilaiset tuhot ja puiden ikä selittävät suuren osan havupuiden harsuuntumisen vaihtelusta. Neulasten rikkipitoisuuksissa ei ollut tapahtunut merkittävää muutosta tutkimusalueen merkittävimpien päästölähteiden läheisyydessä vuoden 1998 tutkimukseen verrattuna, kun otetaan huomioon neulashavaintoalojen toisistaan poikkeava sijoittelu eri tutkimusvuosina. Verrattuna vuonna 1998 toteutettuun tutkimukseen, sormipaisukarpeen vauriot olivat hieman kasvaneet, levä yleistynyt ja ilman epäpuhtauksille herkät lajit harvinaistuneet tutkimusalueella, mutta kokonaisuudessaan muutokset vuosien välillä olivat lieviä. Vaurioituneimman sormipaisukarpeen ja köyhtyneimmän lajiston vyöhykkeet sijoittuivat pääosin samoille alueille molempina tutkimusvuosina eli Joensuun-Hammaslahden väliselle alueelle, Uimaharjuun, Kiteelle ja Nurmeksen ja Lieksan keskusta-alueille, mutta vuonna 2010 köyhtyneimmän lajiston vyöhykkeet olivat hieman laajempia. Päästömäärien lievä kasvu 2000-luvun loppuvuosina on todennäköisesti vaikuttanut jäkäliin ja vaikutus näkyi vielä tässä tutkimuksessa, vaikka päästömäärät ovatkin 2000-luvulla olleet pienempiä kuin 1990-luvulla. Hajapäästöjä aiheuttavan toiminnan (esim. kaivostoiminta, turvetuotanto ja maatalous) lisääntyminen tutkimusalueella voi myös osittain selittää tutkimusvuosien välisiä lieviä muutoksia jäkälälajistossa ja jäkälien kunnossa tausta-alueilla.
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In this doctoral thesis, a power conversion unit for a 10 kWsolid oxide fuel cell is modeled, and a suitable control system is designed. The need for research was identified based on an observation that there was no information available about the characteristics of the solid oxide fuel cell from the perspective of power electronics and the control system, and suitable control methods had not previously been studied in the literature. In addition, because of the digital implementation of the control system, the inherent characteristics of the digital system had to be taken into account in the characteristics of the solid oxide fuel cell (SOFC). The characteristics of the solid oxide fuel cell as well the methods for the modeling and control of the DC/DC converter and the grid converter are studied by a literature survey. Based on the survey, the characteristics of the SOFC as an electrical power source are identified, and a solution to the interfacing of the SOFC in distributed generation is proposed. A mathematical model of the power conversion unit is provided, and the control design for the DC/DC converter and the grid converter is made based on the proposed interfacing solution. The limit cycling phenomenon is identified as a source of low-frequency current ripple, which is found to be insignificant when connected to a grid-tied converter. A method to mitigate a second harmonic originating from the grid interface is proposed, and practical considerations of the operation with the solid oxide fuel cell plant are presented. At the theoretical level, the thesis discusses and summarizes the methods to successfully derive a model for a DC/DC converter, a grid converter, and a power conversion unit. The results of this doctoral thesis can also be used in other applications, and the models and methods can be adopted to similar applications such as photovoltaic systems. When comparing the results with the objectives of the doctoral thesis, we may conclude that the objectives set for the work are met. In this doctoral thesis, theoretical and practical guidelines are presented for the successful control design to connect a SOFC-based distributed generation plant to the utility grid.
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OBJETIVO: descrever as características sociodemográficas dos óbitos por câncer do colo uterino em residentes de Recife, Pernambuco, ocorridos entre 2000 e 2004. MÉTODOS: realizou-se um estudo transversal, populacional, com a inclusão de 323 óbitos por câncer do colo uterino, dos quais 261 encontravam-se registrados no Sistema de Informação sobre Mortalidade e 62 foram identificados após investigação das mortes por câncer em porção não especificada do útero. Obteve-se a mortalidade proporcional para todas as variáveis e foram calculadas medidas estatísticas de tendência central e dispersão para a idade. Quanto ao local de residência e faixa etária, realizou-se o teste do χ2 e obteve-se o coeficiente de mortalidade. RESULTADOS: houve predomínio de óbitos em mulheres com idade inferior a 60 anos (54,7%), negras (60,5%), sem companheiro (67,7%), donas de casa (71,2%) e residentes em bairros com baixa condição de vida (53,3%). A maioria das mortes foi hospitalar (85,1%), das quais 90,2% ocorreram na rede do Sistema Único de Saúde (SUS). O coeficiente de mortalidade variou de 0,3 (na faixa etária inferior a 30 anos) a 54,9/100.00 (em maiores de 80 anos). Comparando-se os óbitos por faixa etária e distrito sanitário com as características da população feminina residente na cidade, evidenciaram-se diferenças estatisticamente significantes (p<0,05). CONCLUSÕES: em Recife, os óbitos por câncer do colo uterino são mais freqüentes em mulheres na idade adulta, negras, sem companheiro, donas de casa, residentes em bairros com baixa condição de vida e atendidas na rede hospitalar do SUS, existindo diferenças no risco de morte entre as faixas etárias e o local de residência.
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1818/06/11 (Numéro 323).
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1818/06/08 (Numéro 323).