Tecnologia dos nanotubos de carbono: tendências e perspectivas de uma área multidisciplinar

An overview of the properties of carbon nanotubes is presented as a function of the structural characteristics and of the method of synthesis of these novel advanced materials. Emphasis is given to the catalytic decomposition of hydrocarbons over metal-supported catalysts and also the role of the support in obtaining homogeneous carbon nanotubes in high yelds is discussed. Some potential and real applications of carbon nanotubes are presented in a perspective view.

Caracterização hidrogeoquímica de água subterrânea em área de influência de futuras instalações de usinas hidrelétricas: bacia hidrográfica do rio Taquari-Antas/RS, Brasil

The identification and characterization of the hydrochemistry of the groundwaters has been done for seven wells. The sampling occurred during three bimonthly campaigns. The results classified the waters as of the calcium bicarbonated type for the majority of the samples, except for one well, whose composition is of the sodium bicarbonated type. The major ions found and how they determine the quality parameters are consistent with the reactions of mineral dissolution of the majority of volcanic rocks and the reactions with intrusion of alkaline rock in only one well. Anomalous values of nitrate in some wells alert to the impact of especially polluting sources at the time the reservoirs of the hydroeletric plant were formed.

Estudo dos efeitos do silício e do fósforo na redução da disponibilidade de metais pesados em área de mineração

This study was developed with a soil contaminated by heavy metals, with the purpose of evaluating the action of silicon and phosphorus as protection agents through simple extractions by DTPA. The collected samples were prepared and incubated with five doses of silicon and five doses of phosphorus, with four replicates, amounting to 100 experimental units. After 30 and 60 days, samples of each treatment were collected, submitted to pH analyses and simple extraction by DTPA. The amounts of DTPA-extracted metals depended on the doses of silicon and phosphorus and on the pH. Treatments with silicon and phosphorus was efficient in decreasing the availability of heavy metals in soil.

A importância das revistas Química Nova e Journal of the Brazilian Chemical Society no crescimento da área de química no Brasil

Quimica Nova and the Journal of the Brazilian Chemical Society are two examples of successful initiatives taken by the Brazilian Chemical Society (SBQ - Sociedade Brasileira de Química), and may serve as models for the scientific societies of developing countries. Pillars of the SBQ, these two periodicals are undeniable demonstrations that idealism, utopia and dignity are the essential ingredients for transforming dreams into reality. Few believed that the Brazilian chemical community would one day have, as it does today, two scientific research periodicals indexed in the principal international data banks.

Aporte atmosférico de amônio, nitrato e sulfato em área de floresta ombrófila densa montana na Serra dos Órgãos, RJ

Wet and dry (dust) deposition was measured in the Serra dos Órgãos National Park. VWM pH was 5.3. Non-sea-salt (nss) SO4(2-) comprised 97% of total SO4(2-). The molar ratio [2(nss-SO4(2-)) + NO3-]/[NH4+ + H+] was 1.1, suggesting that pH is predominantly controlled by H2SO4, HNO3, and NH3. Wet deposition of NH4+, NO3-, and nss-SO4(2-) was respectively 0.59, 0.25, and 0.30 kmol ha-1 yr-1. Assuming that dry deposition of N can comprise 30-50% of its total (dry + wet) deposition, the latter is estimated to be 1.2-1.7 kmol ha-1 yr-1 (17-24 kg N ha-1 yr-1).

Avaliação da pós-graduação da área de química na CAPES e a internacionalização das revistas da Sociedade Brasileira de Química: Journal of the Brazilian Chemical Society e Química Nova

This paper discusses of the use of the Impact Factor in the evaluation of chemistry graduate courses by CAPES and the internationalization of the Journal of the Brazilian Chemical Society and Química Nova.

Comportamento do herbicida hexazinone em área de recarga do aqüífero Guarani cultivada com cana-de-açúcar

São Paulo state (Brazil) has an important area of sugarcane production, mainly for obtaining alcohol and sugar, where there is an intensive use of pesticides. An important recharge zone of Guarani aquifer, with supplies water for the local population, is located at Ribeirão Preto city, so the local behavior of pesticides must be investigated. The GUS index was obtained by using the paramenters Koc and half-life for hezazinone herbicide, determinated in representative soil of this region. This study has demonstrated that there is potential risks of hexazinone leaching to ground water, indicating that this herbicide must be monitored in ground water.

Produção científica e formação de recursos humanos na área de bioquímica em instituições federais do Rio Grande do Sul: fomento estadual

Brazilian scientific production in Biochemistry is growing impressively fast, and Rio Grande do Sul is outstanding in that context. This study aims to outline the state's scientific research profile, given its prominent position in the national scenario. Hence, researchers, laboratories, development of human resources and investments by Foundation for the Support to Research in the State of Rio Grande do Sul (FAPERGS) were identified and mapped. We observed that amount of financial support by FAPERGS decreases in last years. Therefore, there is the necessity to reestablish some of FAPERGS's programs, as well as to increase financial support to Biochemistry departments.

Produção científica da área da Química no desenvolvimento da oceanografia no Brasil

This paper analyses the scientific contribution of chemists and of the Brazilian Chemical Society (SBQ) and its publications to the development of Oceanography in Brazil, as well as major drivers of this participation. A total of 528 articles were analyzed. Most articles (72%) originated in research groups not associated with graduate programs in oceanography. Nearly 50% dealt with the contamination of the marine environment, followed by chemical process studies (32%) and analytical methods development (15%). SBQ journals contributed with 78 articles (14.7% of the total), and rank 1st (QN) and 2nd (JBCS) among scientific journals publishing the analyzed articles.

Chumbo e zinco em águas e sedimentos de área de mineração e metalurgia de metais

Lead metallurgy at Adrianópolis is the largest environmental problem of Paraná, Brazil. The objective of this study was to determine Pb and Zn levels in water and sediment in two catchments by different extraction methods. The high levels of lead in water in most of samples do not allow the human use. Total Pb concentration as high as 795.3 µg L-1 was observed in Ribeira River bank, in a pluvial water stream flowering from a abandoned factory. Due to the high Pb levels in sediments from some sites (maximum of 24,300 mg kg-1) is recommended to avoid the water turbulence.

Redes de colaboração científica na área de química no Brasil: um estudo baseado nas coautorias dos artigos da revista Química Nova

In this paper we built three co-authorship networks displaying the acquaintances between countries, universities and authors that have published papers in Quimica Nova from 1995 to 2008. Our research was conducted applying a bibliometric approach to 1782 papers and over 4200 authors. Centrality measures were used and the most significant actors of each network were pointed out. The results using the centrality metrics and the network structures indicated that Quimica Nova resembles a typical scientific community.

Resíduos de pesticidas em águas superficiais de área de nascente do Rio São Lourenço-MT: validação de método por extração em fase sólida e cromatografia líquida

A multiresidue method using HPLC/DAD for the determination of fourteen pesticides in water based on SPE, using SDVB (styrene divynilbenzene copolymer) as adsorbent was validated. Recoveries from 61 to 120%, relative standard deviation between 2 and 15% and detection limits from 0.07 to 0.75 µg L-1 were obtained. It was applied to 66 surface water samples collected in a degraded area at the headwaters of São Lourenço river, Mato Grosso, Brazil. Eight pesticides were detected in concentrations ranging from 0.15 to 35.25 µg L-1. Considering ecotoxicological data, carbendazim and carbofuran may represent a risk to aquatic organisms. These results draw attention to the contamination of this vulnerable degraded area.

A abordagem de questões ambientais: contribuições de formadores de professores de componentes curriculares da área de ensino de química

This paper presents the results of a study involving current teachers of the chemistry teaching curricular components of twelve Chemistry licentiate courses at state universities in the South and South-east of Brazil. The aim was to analyse how these curricular components can work together to address environmental issues in Chemistry teacher-training. From analysis of the interviews, it can be ascertained for example that environmental themes in the curricular components analysed are treated with differing levels of intensity and perspectives, and in some cases, have a more illustrative character regarding chemistry concepts.

A pesquisa em Ensino de Química como área estratégica para o desenvolvimento da Química

This paper presents an overview of the development of chemical education as a research area and some of its contributions to society. Although science education is a relatively recent area of research, it went through an expressive development in the last decades. As in the whole world, in Brazil also such development is attested by the expressive number of scientific societies, specialized journals, and meetings with growing attendance in the areas of science education in general and chemical education in particular. Following are the main contributions of research in science education related to chemistry teaching: adoption of teaching-learning principles in chemistry education; contextualization of chemical knowledge; interdisciplinary approach to chemistry teaching; use of the history of science for the definition of contents and for the design of curricula and teaching tools; development of specific disciplines for the initial and in-service training of chemistry teachers; publication of innovative chemistry textbooks by university-based research groups; elaboration of official guidelines for high-school level; and evaluation of chemistry textbooks to be distributed to high-school students by the Brazilian government. In spite of a positive impact of such initiatives, science education in Brazil still faces many problems, as indicated by poor results in international evaluations (such as the Program for International Student Assessment). However, changes in such a scenario depend less on the research in chemical education than on the much-needed governmental initiatives aiming at the improvement of both attractiveness of teaching career and structural conditions of public schools. In conclusion, new government investments in education are necessary for continuing the development of chemistry; moreover, scientific societies and decision makers in educational policies should take into consideration the contributions originated from the chemical education research area.