Efecto del secado térmico y el tratamiento alcalino en las características microbiológicas y químicas de biosólidos de plantas de tratamiento de aguas residuales domésticas

We evaluated the effect of thermal drying (60 to 75 ºC and times from 0 to 12.58 h) and alkaline treatment (Ca(OH)2 and CaO at doses from 8 to 10%.) on the microbiological and chemical characteristics of biosolids from the Cañaveralejo WWTP. The results showed that in thermal drying all temperatures studied were sufficient to achieve the sanitation of biosolids. In the alkaline treatment the two types of lime showed the total elimination of fecal coliforms, E. coli and helminth eggs, however, the process of alkalization of biosolids had significant influences on organic carbon and calcium.

Influência do pH nas propriedades físico-químicas, térmicas e mecânicas de filmes de poli(vinil álcool)/poli(ácido acrílico)/aciclovir

Drug-loaded films represent an alternative method for the treatment of skin lesions caused by Herpes simplex, since they facilitate delivery of the drug directly at the site of lesion. The objective of this work was to prepare PVA/PAA films containing AC at pH 2.0 and 4.0. The results show that the pH of the film preparations influences the polymer¾drug interaction kinetic order and the degree of swelling. The mechanism of release of AC from the films obtained at pH 4.0 was anomalous, whereas for the films prepared at pH 2.0 the release followed zero-order kinetics.

Estudo de reações químicas homogêneas via método de Monte Carlo

By using the Monte Carlo simulation platform with probabilistic mathematical functions of the Boltzmann type, , having activation energy and temperature as parameters, it was possible to assess important dynamic aspects of homogeneous chemical reactions of the types A → B and A B. The protocol proved a useful tool in work with the basic concepts of Kinetics and Thermodynamics allowing its application both in class activities and for assisting experimental procedures.

Experimento utilizando grãos para explorar a calibração em análises químicas

The conventional curriculum of Analytical Chemistry undergraduate courses emphasizes the introduction of techniques, methods and procedures used for instrumental analysis. All these concepts must be integrated into a sound conceptual framework to allow students to make appropriate decisions. Method calibration is one of the most critical parameters that has to be grasped since most analytical techniques depend on it for quantitative analysis. The conceptual understanding of calibration is not trivial for undergraduate students. External calibration is widely discussed during instrumental analysis courses. However, the understanding of the limitations of external calibration to correct some systematic errors is not directly derived from laboratory examples. The conceptual understanding of other calibration methods (standard addition, matrix matching, and internal standard) is imperative. The aim of this work is to present a simple experiment using grains (beans, corn and chickpeas) to explore different types of calibration methods.

A INFLUÊNCIA DA LIGAÇÃO DE HIDROGÊNIO EM REAÇÕES QUÍMICAS: REAÇÃO DE PRILESCHAJEW

Theoretical analysis at the BHandHLYP/6-311++G(d,p) level of theory with the support of QTAIM calculations was used to reinvestigate the structure of an intermolecular system formed between ethylene oxide (C2H4O) and formic acid (HCO2H) after the epoxidation known as the Prileschajew reaction. Geometric and infrared vibration results revealed that HO2CH forms a strong hydrogen bond with C2H4O followed by a larger red-shift of the H−O bond. NBO analysis was applied to justify this frequency shift. Finally, QTAIM calculations identified the formation of two hydrogen bonds, namely O···H−O and H···O=C.

ANÁLISES FÍSICO-QUÍMICAS DE BIOFILMES DE SULFATO DE CONDROITOINA MODIFICADO

Numerous investigations are dedicated to the research and development of new polymer materials destined for innovation in pharmaceutical forms. The application of these technological resources has allowed the commercialization of new therapeutic systems for modified drug release. This investigation aimed to evaluate the association of modified chondroitin sulfate with an insoluble polymer, Eudragit® RS 30 D, widely available in the pharmaceutical market. Isolated films were prepared by the evaporation process using a Teflon® plate. The aqueous dispersions (4% m/v) of synthetic polymer received the addition of modified chondroitin sulfate at different ratios. The interactions of the polymer chains in the blends were physicochemically characterized by means of Fourier transform infrared spectroscopy, thermal analyses, differential scanning calorimetry, thermogravimetry and scanning electron microscopy combined with hydration and assays in alkaline pH. The results showed appropriate properties of the coating materials for solid oral forms intended for drug deliver in specific environments.

AVALIAÇÃO DE PROPRIEDADES FÍSICAS E QUÍMICAS DE ELETRODEPÓSITOS DE Ni-W-P OBTIDOS EM CÉLULA DE HULL

Ni–W–P electrodeposits were synthesized in a Hull cell in order to simulate the obtainment under industrial conditions. Complete coverage of panels was accomplished by applying total currents of 1.0 and 2.0 A. Panels obtained with a current of 1.0 A appeared brighter. The best compositional uniformities, as determined by Energy Dispersive Spectrometer (EDS) occurred in the current density ranges of 0.6 to 3.0 A dm−2 and 1.6 to 6.0 A dm−2 obtained with 1.0 and 2.0 A, respectively. However, the best morphological characteristics, as determined by Scanning Electro Microscope (SEM), were observed in those obtained with a total current of 1.0 A. Analysis of corrosion resistance by Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Linear Polarization (PLP) in NaCl have shown significant variations in the amount of corrosion potential, polarization resistance, and even total impedance. The alloys exhibited amorphous character (XRD) and crystallized above 400 °C to Ni and Ni3P phases, and possibly Ni–W, with a subsequent increase in hardness. The results suggest that under industrial conditions, current density variations due to the large and complex geometric shapes of substrates lead to formation of distinct alloys. Furthermore, these materials are potential substitutes for chromium deposits in many applications.

Pequisas físicas e químicas do sistema hidrográfico da região lagunar de Cananéia: I - Cursos de águas

The present elaboration is a "previous note" about two watercourses, Maria Rodrigues and Baguaçú, belonging to Hydrografic System of the Cananeas Lagoon Region in the Southern Part of it he Coast of the Estado de São Paulo, Brazil, which is the objete of our physical and chemical researches. It is based on the first results obtained from our contact with that region, ttfie studies of which are being continued and will still have to confirm or not the previous conclusions, which we are presenting in this "provisional paper". We studied the Maria Rodrigues and the Baguacu under the discussion whether they are to be clasified as a river in the poper sense ot the word or waUer-courses of any other origin. For this purpose we established observatory-stations along their whole course where we collected quantities of water to be analised. The data included in the table nº 1 and 2 refer to the physical and chemical properties of these portions of water. These physical and chemical properties were discussed and compared one with the other according to the observatory-stations, at the same moment and the tide predominating on that occasion. The physical and chemical datas were obtained according to the norms recommended by the Conseil International permanent pour l'Exploration de la Mer, Copenhague. We also presented a sketch of both; we described their relations with regard to the Mar de Cananéia; we inserted comprehensible histograms of the distribution of the observatory-stations, each of them with the respective indices, and at last we tried to correlate the occurrence of the "plancton" with the physical and chemical properties of water as well in the Maria Rodrigues as in the Baguacú. From these researches result the following previous conclusions: 1 - By the data obtained up to now nothing could be formulated as to a cyclical or "seasonal" aspect. 2 - By the comparison of the phenomena which present the rivers in the proper sense of the word and those observed in the Maria Rodrigues and the Baguacú, we are convinced that both are water-courses of the classical type "marigot,". 3 - Their channels are maintained open by the effect of the tide and, more perphaps, by the infiltration-water deriving from the underground-water level owing to the type of the soil of that region, which in mean shows an elevation of 2-4 meters over sea-level. 4 - From tables 1 and 2 and histograms 2 and 3 we stated that the water, not only of the Maria Rodrigues but also of the Baguacú, conserve more or less the same physical and chemical properties, provided that: 1) the localities to be compared are the mouths or equidistant points from them in the lower course, and 2) the moment and tide must be the same. Tables 3a and 3b show sufficiently this supposition.

Resultados científicos do cruzeiro do Baependi e do Vega à Ilha da Trindade: oceanografia física - contribuição para o conhecimento das características físicas e químicas das águas

In May 1950 a trip was undertaken by the ships "Baependi" and "Vega" to the Trindade Island - 20º30'S and 29º20'W - Approximately 1200 km off the coast of Espirito Santo State. This scientific expedition was realized by the iniciative of the Minister J. A. Lins de Barros. In this expedition the supervisor of the oceanographic works was Prof. W. Besnard, the director of the São Paulo Oceanographic Institute. He brougth home 42 samples of water for study, collected upon the insular terrace of the island, referring to the 15 established stations - see table I - with depths varying between 0 m and 115 m. The physical and chemical properties of them are to be seen on table II. The results obtained were compared with those of the German Expedition to the South Atlantic, 1925/27 ("Meteor"), observed at the stations 157-158-159-163 of profile VI and 168-169-170 of profile VII. The mean results obtaneid by the boats "Baependi" and "Vega" are represented on table IV. We constructed vertical sections - I to VI - of each group of Stations, showing the slope of the insular shelves and, in a general manner, the distribution of salinity. We made also longitudinal section - E, M, I - involving the island and corresponding, respectively, to the groups of stations, the farthest, nearest and intermediary ones. As the number of samples received is reduced and consequently the data obtained are few, no conclusions could be deduced. We made only a commentary supposing that the predominating waters surrounding the island are the same as those coming from the mentioned stations on Profile VI, marked by the "Meteor". No indication authorizes the supposition that waters of the Brazil Current or those of Profile VII of the "Meteor" reach the Trindade Island. On the contrary, its waters must be warm and salted to which Albert Defant (Die Troposphaere, Wiss. Erg. D. Atl. Exp. "Meteor" Band VI, 1 Tel Lief. 3, Berlin, 1936) has referred, as the island is located very near to the limits of the perspective diagram of warm water circulation pointed out. (Kieler Meeresforschungen, Inst. Meereskunde, Universit. Kiel, Band VII, Heft 1, S 24, 1950).

Potencialidades e aplicações do ligante dietilditiofosfato de amônio em análises químicas

Este trabalho descreve uma revisão a respeito do uso do ligante dietilditiofosfato de amônio em química analítica e suas potencialidades no campo da análise química espectrofotométrica (UV/VIS) e espectrométrica (AAS, ICP-AES, ICP-MS) em diferentes matrizes e meios. A discriminação de espécies químicas por meio de complexações seletivas de elementos químicos com dietilditiofosfato e a hifenação de técnicas espectroscópicas a etapas de separação como extração em fase sólida, extração líquido-líquido, extração por "cloud point", são outros assuntos abordados neste trabalho.

Características físico-químicas de ácidos húmicos em diferentes etapas da vermicompostagem

Amostras de materiais coletados em diferentes estádios de vermicompostagem foram submetidas a procedimentos de extração de ácidos húmicos. Técnicas de titulação potenciométrica, termogravimetria (DTG), difração de raios X e espectrofotometria no uv/visível e no infravermelho foram utilizadas no estudo desses materiais. Os dados de titulação foram submetidos ao ajuste por regressão não-linear, determinando-se, assim, cinco valores de pKa característicos de cinco classes de grupos tituláveis. Nas curvas DTG, foram observadas duas etapas, sendo a primeira característica da separação de estruturas alifáticas e, ou, alicíclicas e a segunda, a decomposição de estruturas aromáticas. A difratometria de raios X apresentou diferenças marcantes nos resultados, principalmente nos três primeiros picos onde parecem ocorrer reorganização estrutural e polimerização ao longo do processo de vermicompostagem. Os espectros do infravermelho não apresentaram diferenciação entre os espectros. Os valores da razão E4/E6 encontrados estão de acordo com os característicos dos ácidos húmicos, mas não fornecem informações que possam contribuir para a elucidação da estrutura e formação desses ácidos.

Afinidades eletivas e pensamento econômico: 1870-1914

O artigo busca mostrar a aplicabilidade do conceito de "afinidades eletivas" para tratar das relações entre o pensamento econômico, a literatura e a filosofia. Em particular destaca-se o pensamento institucionalista, a escola histórica alemã e o pensamento neoclássico

Sobre as afinidades entre a filosofia de Francis Bacon e o ceticismo

Este texto se ocupa de um exame, em caráter introdutório, das relações entre a reflexão de Bacon acerca das limitações de nossas faculdades e o ceticismo filosófico - um tema pouco considerado pela literatura mais recente, a despeito das muitas referências a tal filosofia. Ainda que, à primeira vista, tais referências possam parecer vagas e imprecisas, pensamos que um exame adequado de algumas delas pode revelar, não apenas a importância do tema para a compreensão de aspectos do seu próprio empreendimento, mas o interesse de Bacon pela literatura cética contemporânea. As peculiaridades de sua própria interpretação, por sua vez, parecem antecipar traços do modo como essa filosofia foi compreendida por filósofos posteriores, como Hume.

Efeito do manejo da entrelinha da seringueira sobre as propriedades químicas do solo, o estado nutricional e o crescimento

O trabalho teve por objetivo analisar a influência do manejo do solo da entrelinha da cultura da seringueira (Hevea brasiliensis) sobre as propriedades químicas do solo, o teor de nutrientes e o crescimento da seringueira. Para isso, implantou-se a seringueira (clones PB 235 e RRIM 701) em Latossolo Vermelho-Escuro, em 1992, no Município de Jaboticabal, SP. Os tratamentos consistiram do manejo da entrelinha com: grade, roçadeira e cultura de cobertura utilizando uma leguminosa kudzu tropical (Pueraria phaseoloides). Após oito anos, foram analisadas algumas propriedades químicas do solo (pH, M.O., H+Al, Ca+2, Mg+2, K+ e P) na entrelinha da cultura, bem como o teor de macro e micronutrientes e o crescimento da cultura em circunferência à altura do peito. Os diferentes manejos da entrelinha da cultura da seringueira afetaram todos os atributos químicos do solo da camada superficial (0-20 cm de profundidade) analisados. O manejo da entrelinha da seringueira com roçadeira mostrou-se importante no sistema solo-planta. A influência do manejo da entrelinha da seringueira na sua nutrição depende do clone utilizado no sistema de produção.

Características físicas e químicas de substratos à base de pó de coco e resíduo de sisal para produção de mudas de sabiá (Mimosa caesalpiniaefolia Benth)

O experimento foi instalado com o objetivo de analisar as características físicas e químicas ocorridas em substratos com diferentes concentrações de pó de coco (PC), resíduo de sisal (RS) e Argissolo Vermelho- Amarelo distrófico (Arg), no crescimento de mudas de sabiá (Mimosa caesalpiniaefolia Benth), produzidas em recipientes com capacidade para 2 dm³. O delineamento utilizado foi o inteiramente casualizado, com 13 tratamentos e quatro repetições, contendo oito vasos por repetição, num total de 416 unidades amostrais. Avaliaram-se as características físicas e químicas, bem como as variáveis da altura total das plantas e do diâmetro do coleto a cada 30 dias, a área foliar, o número de folhas e a massa seca da parte aérea. Recomenda-se o uso de pó de coco como componente para substratos, pois suas propriedades físicas e químicas, aliadas à sua estrutura e durabilidade, apresentaram condições para a produção de mudas de sabiá. Não se recomenda o uso do resíduo de sisal como componente para substratos na produção de mudas de sabiá, pois esse resíduo revelou valores de condutividade elétrica (CE) e pH inadequados ao cultivo.