Otimização do processo de recuperação do cromo de efluentes de curtumes por microemulsões no extrator Morris

The tanning industries are those which transform animal hide or skin into leather. Due to the complexity of the transformation process, greater quantities of chemicals are being used which results in the generation of effluents with residual solids. The chromium in the residual waters generated by tanning tend to be a serious problem to the environment, therefore the recovery of this metal could result in the reduction of manufacturing costs. This metal is usually found in a trivalent form which can be converted into a hexavalent compound under acidic conditions and in the presence of organic matter. The present study was carried out with the objective to recover chromium through an extraction/re-extraction process using micro emulsions. Micro emulsions are transparent and thermodynamically stable system composed of two immiscible liquids, one forming the continuous phase and the other dispersed into micro bubbles, established by an interfacial membrane formed by surface active and co-surface active molecules. The process of recovering the chromium was carried out in two stages. The first, an extraction process, where the chromium was extracted in the micro emulsion phase and the aqueous phase in excess was separated. In the second stage, a concentrated acid was added to the micro emulsion phase rich in chromium in order to obtain a Winsor II system, where the water that formed in the micro emulsion phase separates into a new micro emulsion phase with a higher concentration of chromium, due to the lowering of the hydrophiles as well as the ionisation of the system. During the experimental procedure, a study was initiated with a synthetic solution of chromium sulphate passing onto the effluent. A Morris extractor was used in the extraction process. Tests were carried out according to the plan and the results were analysed by statistical methods in order to optimise the main parameters that influence the process: the total rate of flow (Q), stirring speed (w) and solvent rate (r). The results, after optimization, demonstrated that the best percentuals in relation to the chromium extraction (99 %) were obtained in the following operational conditions: Q= 2,0 l/h, w= 425 rpm and r= 0,375. The re-extraction was carried out at room temperature (28 °C), 40 °C and 50°C using hydrochloric acid (8 and 10 M) and sulphuric acid (8 M) as re-extracting agents. The results obtained demonstrate that the process was efficient enough in relation to the chromium extraction, reaching to re-extraction percentage higher than 95 %.

Investigación sobre los efectos sociales de la urbanización en un área obrera del Gran Buenos Aires = Inquiry into the social effects of urbanization in a working-class sector of Greater Buenos Aires

Los documentos del Seminario fueron publicados por UNESCO en 1961 con el título: La urbanización en América Latina/Urbanization in Latin America

Ensuring quality in qualitative inquiry: Using key concepts as guidelines

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reliability of Web-Based Information in Inquiry Projects

This case study aims at identifying how a community of secondary school students selects web-based information and factors associated with the reliability of online reference sources during their collaborative inquiry (co-inquiry) projects. This study, conducted in a public secondary school in Brazil, focused on information literacy skills for collaborative open learning (colearning). The research is based on qualitative content analysis implemented on the online platform weSPOT. Although students are mindful of the importance of comparing different sources of information they seem not to be aware of reliability in online environments. Teacher's guidance is essential to support co-learners in developing competences, particularly related to critical thinking.

Complexity and information technologies: an ethical inquiry into human autonomous action

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Both the dorsal hippocampus and the dorsolateral striatum are needed for rat navigation in the Morris water maze

The multiple memory systems theory proposes that the hippocampus and the dorsolateral striatum are the core structures of the spatial/relational and stimulus-response (S-R) memory systems, respectively. This theory is supported by double dissociation studies showing that the spatial and cue (S-R) versions of the Morris water maze are impaired by lesions in the dorsal hippocarnpus and dorsal striatum, respectively. In the present study we further investigated whether adult male Wistar rats bearing double and bilateral electrolytic lesions in the dorsal hippocampus and dorsolateral striatum were as impaired as rats bearing single lesions in just one of these structures in learning both versions of the water maze. Such a prediction, based on the multiple memory systems theory, was not confirmed. Compared to the controls, the animals with double lesions exhibited no improvement at all in the spatial version and learned the cued version very slowly. These results suggest that, instead of independent systems competing for holding control over navigational behaviour, the hippocampus and dorsal striatum both play critical roles in navigation based on spatial or cue-based strategies. (C) 2011 Elsevier B.V. All rights reserved.

A mixed methods inquiry into the political economy of agriculture and rural areas in Lebanon

The present work, then, is concerned with the forgotten elements of the Lebanese economy, agriculture and rural development. It investigates the main problematic which arose from these forgotten components, in particular the structure of the agricultural sector, production technology, income distribution, poverty, food security, territorial development and local livelihood strategies. It will do so using quantitative Computable General Equilibrium (CGE) modeling and a qualitative phenomenological case study analysis, both embedded in a critical review of the historical development of the political economy of Lebanon, and a structural analysis of its economy. The research shows that under-development in Lebanese rural areas is not due to lack of resources, but rather is the consequence of political choices. It further suggests that agriculture – in both its mainstream conventional and its innovative locally initiated forms of production – still represents important potential for inducing economic growth and development. In order to do so, Lebanon has to take full advantage of its human and territorial capital, by developing a rural development strategy based on two parallel sets of actions: one directed toward the support of local rural development initiatives, and the other directed toward intensive form of production. In addition to its economic returns, such a strategy would promote social and political stability.

Credit-Default-Swaps and the 2008 Financial Crisis: An Inquiry into the Underlying Legal Origins and the European Union’s Regulatory Reforms

After the 2008 financial crisis, the financial innovation product Credit-Default-Swap (CDS) was widely blamed as the main cause of this crisis. CDS is one type of over-the-counter (OTC) traded derivatives. Before the crisis, the trading of CDS was very popular among the financial institutions. But meanwhile, excessive speculative CDSs transactions in a legal environment of scant regulation accumulated huge risks in the financial system. This dissertation is divided into three parts. In Part I, we discussed the primers of the CDSs and its market development, then we analyzed in detail the roles CDSs had played in this crisis based on economic studies. It is advanced that CDSs not just promoted the eruption of the crisis in 2007 but also exacerbated it in 2008. In part II, we asked ourselves what are the legal origins of this crisis in relation with CDSs, as we believe that financial instruments could only function, positive or negative, under certain legal institutional environment. After an in-depth inquiry, we observed that at least three traditional legal doctrines were eroded or circumvented by OTC derivatives. It is argued that the malfunction of these doctrines, on the one hand, facilitated the proliferation of speculative CDSs transactions; on the other hand, eroded the original risk-control legal mechanism. Therefore, the 2008 crisis could escalate rapidly into a global financial tsunami, which was out of control of the regulators. In Part III, we focused on the European Union’s regulatory reform towards the OTC derivatives market. In specific, EU introduced mandatory central counterparty clearing obligation for qualified OTC derivatives, and requires that all OTC derivatives shall be reported to a trade repository. It is observable that EU’s approach in re-regulating the derivatives market is different with the traditional administrative regulation, but aiming at constructing a new market infrastructure for OTC derivatives.

On the way to light the dark: a retrospective inquiry into the registered cases of domestic violence towards women over a six year period with a semi-quantitative analysis of the corresponding forensic documentation

Domestic violence victims are increasingly identified at emergency departments (ED). Studies report a prevalence of 6-30%; women are more frequently affected and to a more serious extent than men. Studies have shown that without screening domestic violence victims are often not recognised. The primary aim of the study is to collect data descriptive of domestic violence victims and to show whether medical documentation meets the requirements of forensic medicine.

The Investigation of the Ways in Which Gender Stereotypes are Perpetuated through Questioning and Assessment Strategies in Inquiry-Based Science Classroom

The purpose of this study was to investigate the questioning strategies of preservice teachers whenteaching science as inquiry. The guiding questions for this research were: In what ways do the questioning strategies of preservice teachers differ for male and female elementary students when teaching science as inquiry and how is Bloom’s Taxonomy evident within the questioning strategies of preservice teachers? Examination of the data indicated that participants asked a total of 4,158 questions to their elementary aged students. Of these questions, 974 (23%) were asked to boys, and 991 (24%) were asked to girls. The remaining questions (53%) were asked to the class as a whole, therefore no gender could be assigned to these questions. In relation to Bloom’s Taxonomy, 74% of the questions were basic knowledge, 15% were secondary comprehension, 2% were application, 4% were analysis, 1% were synthesis, and 3% were evaluation.

Predictors of vaginal practices for sex and hygiene in KwaZulu-Natal, South Africa: findings of a household survey and qualitative inquiry

Vaginal practices in sub-Saharan Africa may increase HIV transmission and have important implications for development of microbicides and future HIV prevention technologies. It remains unclear which women undertake vaginal practices and what factors predict prevalence, practice type and choice of products. Using cross-sectional data from mixed research methods, we identify factors associated with vaginal practices among women in KwaZulu-Natal, South Africa. Data were gathered through focus group discussions, in-depth and key-informant interviews, followed by a province-wide, multi-stage cluster household survey, using structured questionnaires in face-to-face interviews with 867 women. This paper details six types of vaginal practices, which--despite their individual distinctiveness and diverse motivations--may be clustered into two broad groups: those undertaken for purposes of 'hygiene' (genital washing, douching and application) and those for 'sexual motivations' (application, insertion, ingestion and incisions). Multivariate analysis found significant associations between 'hygiene' practices and media access, religiosity and transactional sex. 'Sexual' practices were associated with partner concurrency, religiosity and use of injectable hormonal contraceptives. Future interventions relating to vaginal practices as well as microbicides need to reflect this characterisation of practices as sexual- and/or hygiene-related.

The Repairing of Misconceptions through the Use of Inquiry-Based Activities

Misconceptions exist in all fields of learning and develop through a person’s preconception of how the world works. Students with misconceptions in chemical engineering are not capable of correctly transferring knowledge to a new situation and will likely arrive at an incorrect solution. The purpose of this thesis was to repair misconceptions in thermodynamics by using inquiry-based activities. Inquiry-based learning is a method of teaching that involves hands-on learning and self-discovery. Previous work has shown inquiry-based methods result in better conceptual understanding by students relative to traditional lectures. The thermodynamics activities were designed to guide students towards the correct conceptual understanding through observing a preconception fail to hold up through an experiment or simulation. The developed activities focus on the following topics in thermodynamics: “internal energy versus enthalpy”, “equilibrium versus steady state”, and “entropy”. For each topic, two activities were designed to clarify the concept and assure it was properly grasped. Each activity was coupled with an instructions packet containing experimental procedure as well as pre- and post-analysis questions, which were used to analyze the effect of the activities on the students’ responses. Concept inventories were used to monitor students’ conceptual understanding at the beginning and end of the semester. The results did not show a statistically significant increase in the overall concept inventory scores for students who performed the activities compared to traditional learning. There was a statistically significant increase in concept area scores for “internal energy versus enthalpy” and “equilibrium versus steady state”. Although there was not a significant increase in concept inventory scores for “entropy”, written analyses showed most students’ misconceptions were repaired. Students transferred knowledge effectively and retained most of the information in the concept areas of “internal energy versus enthalpy” and “equilibrium versus steady state”.