SOUTHERN JOURNAL OF SCIENCES

Background: Determining chlorine in water ensures safety. Among other methods, the DPD colorimetric method is used. The DPD Method relies on colorimetric reactions to measure free and total chlorine concentration in water samples with pink compound formation. Aims: To perform a comparative chlorine analysis using DPD, assessing reagents from 3 makers and 2 Hach instruments to identify disparities and propose adjustments for more accurate measurements. Methods: Hach High-Range and Low-Range Free chlorine determination procedures were followed. DR300 and POCKET Colorimeter II spectrophotometers were used. Tests were conducted for each DPD manufacturer in low/high ranges and in two HACH devices to determine the chlorine concentrations. Hach was used as the reference; LaMotte and PoliControl compared against it. Statistical analyses were compiled using MS Excel. Results: The tests findings were gathered in Tables 1-5. JavaScript and HTML scripts were created to convert LaMotte and PoliControl outcomes into values equivalent to those of HACH through linear interpolation. Discussion: Various DPD reagents and equipment provided slightly different readings, prompting empirical evaluation of these differences. Adjusting the results to Hach's results was selected as both the reagent and spectrophotometer were from the same brand. Differences in spectrophotometer readings were more pronounced in high-range tests nearing the upper limit of the test. Conclusions: Equipment variations caused minor result differences; DPD reagents are not interchangeable without correlation. The Open-source code developed aided in reducing reading disparities.

Background: The Second Southern Science Conference (SSCON 2024) represents a significant milestone in international scientific collaboration, bringing together researchers from twelve nations across multiple continents. The conference, held in Mendoza, Argentina, and co-hosted by the University of Vassouras in Brazil, marked both the 64th anniversary of Universidad de Mendoza and the 20th anniversary of Periódico Tchê Química, demonstrating the growing importance of cross-border academic partnerships. Aim: This study aimed to document and analyze the outcomes and impact of the Second Southern Science Conference, focusing on participation metrics, collaborative patterns, and institutional contributions while highlighting the significance of the hybrid format in facilitating global scientific dialogue. Methods: The analysis involved quantitative assessment of conference participation metrics, including the number of approved papers, author distributions, and institutional representation. The study examined participation patterns across countries and institutions, analyzing collaboration trends through statistical data visualization and comparative analysis of submission rates. Results: The conference achieved significant participation metrics with 65 approved papers and 242 contributing authors, averaging 4 authors per paper. The Universidad Nacional de Córdoba emerged as the leading institution, showcasing its 4 centuries legacy of academic excellence. The analysis revealed strong representation from Latin American institutions, with Brazil and Argentina leading in submissions. Most papers involved 2-5 collaborators, indicating effective research collaboration patterns. Over 500 people participated in the event through both in-person and virtual attendance options. Discussion: The hybrid format successfully facilitated broader international participation and knowledge exchange, which is particularly beneficial for addressing contemporary global challenges. The strong showing from Latin American institutions highlights the region's growing influence in international scientific discourse. The conference's interdisciplinary nature fostered new collaborative initiatives and research partnerships. Conclusions: The conference demonstrated the effectiveness of hybrid international scientific events in fostering global collaboration and knowledge exchange. Areas for improvement were identified, including extended submission timelines and establishment of a permanent management committee. The success of this edition supports the planning of future iterations, with the next edition scheduled to be held in Vassouras, Rio de Janeiro.

A new phase of the (CuAlSe₂)_1-x(TaSe)_x alloy system was synthesized by the melt and annealingtechnique and studied by SEM, DTA, and XRPD techniques. Its structure has been refined by the Rietveld methodusing X-ray powder diffraction data. The new alloy corresponds with the stoichiometry Cu_0.4Al_0.3TaSe₂. Thiscompound crystallizes in the hexagonal space group 𝑃6ത𝑚2 (Nº 187) with a MoS₂-type structure, and unit cellparameters a = 3.455(2) Å, c = 13.423(4) Å, V = 138.7(1) Å3, Z =2. The crystal structure is based on the MoS₂-type of stacking of TaSe₂ layers with a partial ordering of Cu and Al cations over the tetrahedral sites. The powderpattern was composed of 63.1% of the principal phase Cu_0.4Al_0.3TaSe₂ and 29.9% of CuAlSe₂, 7.0% of TaSe₃, asthe secondary phases.