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Digital information and communication technology tools have been used as allies in teaching. Chemistry teaching sometimes requires practical activities in laboratories to elucidate the content better, and using videos aimed at this approach can help in the teaching-learning process. This descriptive, qualitative and quantitative study aims to describe the production of manual videos to handle equipment in chemistry laboratories and analyze the scope of the material produced and made available on the "Projeto AQuí" channel on YouTube. Undergraduate students' teaching material was prepared, following the pre-production, production, and post-production steps described in this work. Through the indicators obtained by Google Analytics, it was possible to verify the impact of the material produced. Through the comments left voluntarily on the page, it was possible to perceive viewers' satisfaction with the material. Based on the metrics analyzed, the "Projeto AQuí" channel on YouTube fulfills its proposal to disseminate material on laboratory operations, with a national and international reach. Keywords: DICT. Technology in education.Video. Laboratory equipment. As ferramentas de tecnologia digitais da informação e comunicação vem sendo utilizadas como aliadas no ensino. O ensino de química por vezes necessita de atividades práticas em laboratórios para melhor elucidar o conteúdo, e utilizar vídeos voltados para esta abordagem podem auxiliar no processo de ensino aprendizagem. Este estudo, de caráter descritivo, qualitativo e quantitativo, tem por objetivo descrever a confecção de vídeos-manuais voltados ao manuseio de equipamentos em laboratórios de química, e analisar o alcance e a satisfação do material produzido e disponibilizado no canal “Projeto AQuí” no YouTube. O material didático foi elaborado por alunos de graduação, seguindo os passos de pré-produção, produção e pós produção descritos neste trabalho. Através dos indicadores obtidos pelo YouTube Analytics, foi possível verificar o alcance do material produzido, e através dos comentários deixados voluntariamente na página foi possível perceber a satisfação dos espectadores com o material. Com base nas métricas analisadas, o canal “Projeto AQuí” no YouTube cumpre sua proposta de divulgação de material sobre operações laboratoriais, com um alcance nacional e internacional, sendo utilizado por instituições de ensino técnico e de ensino superior. Palavras-chave: TDIC. Material didático. Tecnologia na educação. Vídeo. Equipamentos de laboratório.

This paper describes the optimization of a sample preparation method using response surface methodology for Al, Cd, Cu, Fe, Mg, Mn, Mo, Na, Ni and Ti determinations in samples of rice husk and rice husk ash by MIP OES. Sample preparation was performed using a reflux system adapted to the digestion tubes. This system allowed the decomposition of the samples without the necessity of replacement of the acids during this step without any loss of volatile elements. The decompositions were performed with 3.6 mL of HNO3 and 1.4 mL of H2SO4 for 205 min in a digester block at 225 ºC. The detection limit for determination of respective analytes in both samples were satisfactory. The RSDs for the analytes were less than 10%. Moreover, the accuracy of the method can be verified by recovery tests, whose values ranged from 82 to 115% for husk samples and 82 to 120% for ashes. The proposed method was presented as a simple, safe and low cost procedure being suitable for sample preparation and subsequent determination of metals by MIP OES.

This paper describes the method optimization using response surface methodology for Cu, Fe, Zn and Na determinations in coal and ash samples by spectrometry techniques. The sample preparation was performed using a recirculation system adapted in the digestion tubes. This system allowed increase of temperature in the digester block above the boiling point of the reaction medium, avoiding acid evaporation during the heating. The digestions were realized with HNO3 and H2O2 for 1 h in a digester block at 145 °C. The limits of detection for determination of Cu, Fe, Zn and Na in both samples were satisfactory. The RSD for the analytes were lower than 6.0%. Statistical tests showed that results for all analytes do not vary significantly with official method (ASTM), considering a confidence limit of 95%. Besides, the accuracy was verified by recovery tests, whose values ranged from 92.7 to 104.7% in coal, and 98.7 to 115.3% in ash.

A new method for microwave assisted extraction (MAE) of meat lipids using a non-halogenated solvent and at low temperature was developed. The effect of microwave irradiation on lipid oxidation during extraction was verified by conjugated dienes, peroxide index, volatile compound (hexanal, pentanal and propanal) and fatty acid analyses. The method showed to be precise and accurate at comparison with Folch extraction and by validation with standard reference material. No changes occurred in the fatty acid composition and no lipid oxidation productswere detected. The optimized and validatedmethodwas applied tomeatswith different lipid contents. The results showed thatMAE can be used to study lipids frommeat sampleswithout the risk of chemical changes during the extraction process, allowing for automation, precision, accuracy, reduction in extraction time, lower cost, reductions in sample size and solvent consumption, hence producing fewer residues for the environment.

p. 1-5 Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2014-04-15T14:23:08Z No. of bitstreams: 1 PhysRevLett.111.183203.pdf: 699711 bytes, checksum: 0da26fa2f8dabf69d8021b58f70a09ec (MD5) Approved for entry into archive by Rodrigo Meirelles (rodrigomei@ufba.br) on 2014-09-09T14:22:41Z (GMT) No. of bitstreams: 1 PhysRevLett.111.183203.pdf: 699711 bytes, checksum: 0da26fa2f8dabf69d8021b58f70a09ec (MD5) Made available in DSpace on 2014-09-09T14:22:41Z (GMT). No. of bitstreams: 1 PhysRevLett.111.183203.pdf: 699711 bytes, checksum: 0da26fa2f8dabf69d8021b58f70a09ec (MD5) Previous issue date: 2013 We report the direct detection of two metastable H(2S2) atoms coming from the dissociation of a single cold H2 molecule, in coincidence measurements. The molecular dissociation was induced by electron impact in order to avoid limitations by the selection rules governing radiative transitions. Two detectors, placed close to the collision center, measure the neutral metastable H(2S2) through a localized quenching process, which mixes the H(2S2) state with the H(2P2), leading to a Lyman-α detection. Our data show the accomplishment of a coincidence measurement which proves for the first time the existence of the H(2S2)-H(2S2) dissociation channel.

We have performed an experimental investigation into the interaction of vacuum-ultraviolet synchrotron radiation with pyridine molecules in the gas phase. Specifically, a double-ion chamber spectrometer was used to measure the absolute photoabsorption cross sections and the photoionization quantum yields from the ionization threshold to 21.5 eV. Moreover, photoionization and neutral-decay cross sections in absolute scale were derived from these data. In addition, the fragmentation pattern was investigated as a function of the photon energy by using a time-of-flight mass spectrometer and the photoelectron-photoion coincidence technique. Thus, the absolute partial ionization cross sections for each ionic fragment were obtained. Comparisons are made with experimental data available in the literature.