Determinação da Concentração de Clorofila-a por Sensoriamento Remoto no Reservatório de Chapéu d’Úvas (Mg), Brasil

Na atualidade, um grande impacto nos reservatórios de água doce é a eutrofização, que afeta diretamente o tratamento e uso da água para abastecimento público, navegação, fauna e flora aquática e impacto visual. A clorofila-a é um dos indicadores de estado trófico da água e pode ser determinada utilizando sensoriamento remoto. Desta forma, este estudo objetivou determinar a concentração de clorofila-a na barragem de Chapéu d’Uvas em Juiz de Fora (Brasil), um dos principais mananciais de abastecimento público da cidade. Através de um modelo utilizando imagens do satélite Sentinel-2 foi avaliado o comportamento espaço-temporal da concentração do componente, foi correlacionado com dados de pluviosidade, temperatura, evaporação e uso e ocupação do solo em torno da barragem. Também foi aplicado um modelo para determinar o índice de estado trófico, que apresenta o grau de trofia que o corpo hídrico se encontra, classificando Chapéu d’Uvas como estado mesotrófico. Os resultados se mostraram satisfatórios para a espacialização e análise temporal da concentração de clorofila-a, a correlação com os dados de evaporação nos permitiu observar uma compatibilidade direta com a concentração do componente e verificou-se valores de clorofila-a acima da média do reservatório nas regiões de entradas de água pelos riachos e próximos as margens com menos cobertura de vegetação.Determination of Chlorophyll-a Concentration from Remote Sensing in Chapéu d’Úvas Reservoir (State of Minas Gerais, Brazil) A B S T R A C TCurrently, one of the great impacts on the freshwater reservoirs is eutrophication, which directly affects the treatment and use of water for public water supply, navigation, aquatic fauna and flora and visual impact. Chlorophyll-a is one of the water trophic state indicators and it can be determined using remote sensing. Thus, this study aimed to determine chlorophyll-a concentration in Chapéu d’Uvas dam, in Juiz de Fora (Brazil), one of the main water sources of public water supply for the city. From a model that uses Sentinel-2 satellite images, the spatial-temporal behavior of that component concentration was evaluated and correlated with data regarding rainfall, temperature, evaporation, and soil use and occupation around the dam. A model was also applied to determine trophic state index, which presents the body of water trophic state, classifying Chapéu d’Uvas as mesotrophic state. The results were satisfactory regarding spatialization and temporal analysis of chlorophyll-a concentration. The correlation with evaporation data permitted us to observe a direct correspondence with the component concentration. Chlorophyll-a values higher than the reservoir average were found in creek inlets and near the shore with lower vegetal cover.Keywords: eutrophication, Sentinel-2, quality of water, inland waters, trophic state

Using spectrometric analysis for indirect estimation of 146S component concentration while measuring FMDV RNA amount

Foot and mouth disease has a negative impact on economy due to the high cost of eradication campaigns and stringent measures imposed on domestic and international trade in animal products. Prevention and control measures include mass vaccination of susceptible animals and control of post-vaccination immunity level. Concentration of 146S particles, which are the main component affecting the vaccine immunogenicity, is determined during commercial scale production of FMD vaccines. The paper assesses feasibility of spectrometric analysis for indirect determination of 146S component concentration while measuring amount of FMDV RNA isolated after serological binding. This method is cheap, easy-to-use and makes it possible to determine indirectly concentration of FMDV 146S particles in inactivated vaccine raw materials within 3–4 hours. Study of cultural FMDV suspensions shows that the linear model С146S = (3.9 × NRNA 146S + 566,783,689)/ 280,818,944,837 makes it possible to estimate FMDV 146S component concentration in the vaccine raw materials with the help of a spectrometric analysis. The actual results obtained in real-time reverse transcription – polymerase chain reaction (rtRT-PCR) were 97.0–99.9% consistent with the expected results of the spectrometric analysis used to determine cultural FMDV 146S component concentration. When compared to a complement fixation test, the actual results were 94.5–99.5% in line with the expected ones. The actual results for positive control were 99.0–99.6% in line with the expected ones. As expected, no FMDV genome or 146S particles were detected in the negative control sample.

Determination of FMDV 146S particle concentration by spectrometric method during viral RNA quantification

During FMD vaccine production, special attention is paid to the concentration of 146S particles bearing the critical biological features of FMDV and being the main components that have an effect on vaccine immunogenicity. For this reason, each batch of vaccine raw material is tested for 146S component concentration. The paper presents the results of the use of a spectrometric method for whole particle concentration determination during quantification of FMDV RNA extracted after immune capture. It is an inexpensive, easy-to-perform method allowing for determination of FMDV 146S particle concentration in the non-inactivated culture suspension. 146S particle concentration was found to depend on the number of RNA molecules extracted from virions after their strain-specific immune capture and quantitatively detected by the spectrometric method. The presented method allows for determination of 146S component concentration in the non-inactivated vaccine raw material using the proposed linear model. The spectrometric method showed 94.5–99.5% correlation with real time reverse transcription polymerase chain reaction and complement fixation test based on the results of tests of 360 non-inactivated suspensions of FMDV of all types. Tests of the positive control demonstrated 99.0–99.6% compatibility of actual and expected results. FMDV genome and 146S particles were not detected in the negative control, and that was in line with expectations.

Technology of Reconditioning with Hardening of Working Elements of Construction and Road Machines by Composite Coatings

The article gives the description of the developed technology of increasing wear resistance of working elements of national and foreign constructional and road machines by composite coatings, obtained on working elements cutting surfaces applying Carbo Vibro Arc Hardening method (CVAH). The technology includes the following basic operations: cleaning and fault detection of the working element, removal of the worn cutting element, compensating element production, its sharpening and welding, preparation of metal and ceramic paste for Carbo Vibro Arc Hardening method (CVAH) and its application, Carbo Vibro Arc Hardening method (CVAH) of the harden cutting surface of the working element. When hardening new working elements technological process operations connected with production and welding the compensating element is not performed. According to the carried out results the rational composition and component concentration of the paste that provides significant increase of working elements wear resistance.

The effect of Ag, Au, Pt, and Pd on the surface properties, photocatalytic activity and toxicity of multicomponent TiO2-based nanomaterials

A better understanding how to the component concentration, photocatalytic properties and toxicity of multicomponent TiO2-based nanomaterials (NMs) may lead to rational design of new and safe NMs with wide application in air purification.

Temporal reflection of electromagnetic waves in simple polar-molecule reactions

Purpose The purpose of this paper is to present the temporal reflection of electromagnetic waves (EMWs) in simple polar-molecule reactions whose polarization changes with the proceeding of the reactions. Design/methodology/approach At a temporal boundary, based on the continuity of the electric displacement and magnetic induction, the reflected condition of EMWs is obtained, and the expression of the transmission and reflection coefficients in the reactions is derived. Subsequently, a one-dimensional model is used to validate the reflected condition and expression. Findings If the time scale of the component concentration variation is greater than the wave period, the polarization of the reactions at a temporal boundary is continuous. The reflection does not happen. On the other hand, when the time scale of the component concentration variation is smaller than the wave period, the polarization is not continuous at a temporal boundary. The impedance of the reactions at the temporal boundary changes and the reflection occurs. Originality/value The results may be helpful in disclosing the non-uniform distribution of EMWs in chemical reactions.