Flow batteries can play an important role as energy storage media in future electricity grids. Organic compounds, based on abundant elements, are appealing alternatives as redox couples for redox flow batteries. The straightforward scalability, the independence of material sources, and the potentially attractive price motivate researchers to investigate this technological area. Four different benzyl-morpholino hydroquinone derivatives were synthesized as potential redox active species. Compounds bearing central symmetry were shown to be about an order of magnitude less soluble in water than isomers without central symmetry. Counter ions also affected solubility. Perchlorate, chlorate, sulfate and phosphate anions were investigated as counter ions. The formations of different polymorphs was observed, showing that their solubility is not a function of their structure. The kinetics of the transformation can give misleading solubility values according to Ostwald’s rule. The unpredictability of both the kinetics and the thermodynamics of the formation of polymorphs is a danger for new organic compounds designed for flow battery applications.

Owing to their broad range of redox potential, quinones/hydroquinones can be utilized for energy storage in redox flow batteries. In terms of stability, organic catholytes are more challenging than anolytes. The two-electron transfer feature adds value when building all-quinone flow battery systems. However, the dimerization of quinones/hydroquinones usually makes it difficult to achieve a full two-electron transfer in practical redox flow battery applications. In this work, we designed and synthesized four new hydroquinone derivatives bearing morpholinomethylene and/or methyl groups in different positions on the benzene ring to probe molecular stability upon battery cycling. The redox potential of the four molecules were investigated, followed by long-term stability tests using different supporting electrolytes and cell cycling methods in a symmetric flow cell. The derivative with two unoccupied ortho positions was found highly unstable, the cell of which exhibited a capacity decay rate of ~50% per day. Fully substituted hydroquinones turned out to be more stable. In particular, 2,6-dimethyl-3,5-bis(morpholinomethylene)benzene-1,4-diol (asym-O-5) displayed a capacity decay of only 0.45%/day with four-week potentiostatic cycling at 0.1 M in 1 M H3PO4. In addition, the three fully substituted hydroquinones displayed good accessible capacity of over 82%, much higher than those of conventional quinone derivatives.

Within the SIM RMO, certain NMIs/ DIs have indicated the need to demonstrate their measurement capability for the determination of ethanol in aqueous matrices. Reflecting upon the current situation, the SIM Chemical Metrology Working Group (CMWG) conducted a second regional Key Comparison in 2016 linked to the CCQM-K27, SIM.QM-K27. The RMO Key Comparison SIM.QM-K27 was coordinated by INMETRO, who demonstrated capability in the CCQM-K27.2 subsequent study: determination of ethanol in aqueous media. INMETRO also coordinated the first SIM RMO Key Comparison SIM.QM-K1. For SIM.QM-K27, two levels of ethanol in water solutions were gravimetrically prepared by INMETRO with a concentration range between 0.5 mg/g and 5 mg/g. The gravimetric value of the aqueous ethanol solutions was used to link SIM.QM-K27 to the CCQM-K27 Key comparison reference value (KCRV). The gravimetric values for SIM.QM-K27 Level 1 and Level 2 were (0.814 ± 0.008) mg/g (U k =2 ) and (3.818 ± 0.038) mg/g (U k =2 ), respectively. The KCRV was determined using the purity-corrected gravimetric preparation values. The KCRV uncertainty was assigned as 1 % from the reference values in order to give the same uncertainty as in the CCQM-K27.2 comparison. Fourteen laboratories took part in this regional KC, from SIM and other RMOs. One participant (INACAL) did not send results and thus it's capability was not evaluated. Ten of the thirteen participants in the SIM.QM-K27 demonstrated their ability to measure ethanol in aqueous matrix in the concentration range of 0.5 mg/g to 5 mg/g (both levels). One participant (ISP) demonstrated its ability to measure ethanol in aqueous matrix only at the low level (0.5 to 1.5 mg/g) and another participant (INM) demonstrated its ability to measure ethanol in aqueous matrix only at the high level (1.5 to 5.0 mg/g). NIMT did not demonstrate its ability to measure ethanol in aqueous matrix from 0.5 mg/g to 5 mg/g (both levels). The abilities demonstrated by the participants should be indicative of their ability to provide reference measurements for ethanol content in aqueous samples for both forensic and commodities applications. This report presents the results of the SIM Key comparison SIM.QM-K27. Successful participation in SIM.QM-K27 demonstrates the following measurement capabilities in determining mass fraction of ethanol in mass fraction range from 0.5 mg/g to 5 mg/g in an aqueous matrix. KEY WORDS FOR SEARCH Key comparison and ethanol in water Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Resumo Este artigo apresenta uma análise sobre o trabalho dos/as assistentes sociais no Instituto Federal de Educação de Santa Catarina, em sua relação com o processo de construção da identidade profissional. A partir do final dos anos 2000, observa-se uma expansão no número de assistentes sociais atuando na política educacional, com a constituição do Programa Nacional de Assistência Estudantil e da Rede Federal de Educação Profissional, Científica e Tecnológica, requisitado, principalmente, para a execução das ações de assistência estudantil. As demandas, requisições e condições de trabalho são elementos que corroboram a construção do projeto ético-político da profissão, e refletir sobre tais aspectos possibilita compreender a realidade para além da sua aparência imediata. Este estudo, fundamentado no materialismo histórico-dialético, desenvolveu-se com base na pesquisa bibliográfica e documental e na pesquisa de campo, utilizando-se do questionário para o levantamento de dados. Os resultados apontam limites e possibilidades ao trabalho dos/as assistentes sociais no Instituto, demonstrando que a construção da identidade profissional ocorre em meio à contradição posta entre as determinações do trabalho assalariado, ao qual os/as assistentes sociais estão sujeitos, e o direcionamento social que se busca imprimir ao exercício profissional, tendo em vista a materialização do projeto profissional.