Avaliação do impacto da utilização de parceria público-privada para construção e operação de unidades municipais de educação infantil em Belo Horizonte

As Parcerias Público-Privadas (PPP) de infraestrutura escolar são cada vez mais utilizadas no mundo, entretanto as avaliações de impacto desse modelo ainda são escassas. O presente estudo contribui para essa área do conhecimento ao avaliar o impacto da utilização de PPP tanto na construção como na operação das Unidades Municipais de Educação Infantil (UMEIs) de Belo Horizonte (BH). A metodologia de pesquisa foi baseada na comparação de 46 UMEIs, sendo 27 unidades de PPP e 19 unidades construídas e operadas no modelo tradicional de contratação pública. Em relação ao impacto na construção, os principais resultados são que o tempo de obra das unidades de PPP foi 45% menor e que 79% das unidades tradicionais foram entregues fora do prazo contratado de 13 meses, enquanto que nenhuma PPP foi entregue acima deste prazo. Além disso, a PPP permitiu aumentar a escala na construção das UMEIs, superando as limitações do modelo tradicional. Dentre as principais evidências encontradas quanto ao impacto na operação, pode-se citar que os diretores de unidades de PPP afirmam ter 25% mais tempo para focar nas atividades pedagógicas, pois gastam menos tempo na gestão dos serviços não pedagógicos, e que o grau de satisfação com os serviços de manutenção das instalações físicas é substancialmente maior nessas unidades. Os resultados positivos para PPP só não apareceram em relação aos serviços de manutenção de TI. Uma limitação deste trabalho foi não conseguir realizar a comparação de custos das duas modalidades. O estudo pretende contribuir para o aprimoramento dos modelos regulatórios de PPPs em educação e para a discussão sobre o papel que pode ser desempenhado pelas PPPs na redução do déficit de infraestrutura escolar.

Avaliação da operação de numerário brasileiro pela abordagem de cadeias de suprimento sustentáveis

A operação de numerário brasileira é apoiada por uma das maiores cadeias de suprimento do país, envolvendo o fluxo de cédulas e moedas entre os bancos, praticamente todos os participantes da economia e toda a população. Pela sua dimensão e abrangência geográfica, essa cadeia produz significativo footprint de carbono. O presente estudo procura explorar essa operação usando a abordagem de cadeias de suprimento sustentáveis, analisando a estrutura da cadeia, seu gerenciamento e sugerindo melhorias a serem implantadas para minimizar a emissão de carbono equivalente desta cadeia.

Eutrofização e capacidade de carga de fósforo de seis reservatórios a bacia do Rio Seridó, região semi-árida do Estado do RN

The eutrofization is a natural process of accumulation of nutrients in aquatic´s body that it has been accelerated for the human´s actives, mainly the related with the activities of camp, industrial and the inadequate disposition of the domestic sewage. The enrichment of the aquatic´s body with nutrients, mainly the nitrogen and the phosphorus, and the consequent proliferation of algae and Cyanobacteria can commit the quality of the water for the public provisioning, for the fish farming and for other ends. The problem becomes more critical when there is a shortage of water naturally as in the semi-arid area of the Brazilian northeast. Before that problem this work had as objective evaluates the trophic state of six reservoirs of the basin of River Seridó of Rio Grande of Norte and also estimate the capacity of load of match of the reservoir and risk probabilities based on the established limits by the resolution Conama 357/05. The results demonstrate that the six reservoirs are eutrofization, with concentration of total phosphorus and cloro a in the water upster to 50 e 12 μg l-1. The results show that space homogeneity exists in the state trophic of the reservoirs, but a significant variation interanual in function of the increase of the concentrations of nutrients and decrease of the transparency of the water with the reduction of the body of water accumulated in the reservoirs.The results of the simulation risk estocastic show that the reservoirs could receive annually from 72 to 216 Kg of P, assuming a risk of 10% of increasing in more than 30 μg l-1 the annual medium concentrations of total match in the water of these reservoirs. This load could be high in until 360 kg of P a year in case the managers assume a risk of 10% of increasing in more than 50 μg l-1 the annual medium concentrations of total phosphorus in the waters of these reservoirs

Comunidades zooplanctônicas como bioindicadoras da qualidade da água de quatro reservatórios da região semi-árida do Rio Grande do Norte

The response of zooplankton assemblages to variations in the water quality of four man-made lakes, caused by eutrophication and siltation, was investigated by means of canonical correspondence analysis. Monte Carlo simulations using the CCA eingenvalues as test statistics revealed that changes in zooplankton species composition along the environmental gradients of trophic state and abiogenic turbidity were highly significant. The species Brachionus calyciflorus, Thermocyclops sp. and Argyrodiaptomus sp. were good indicators of eutrophic conditions while the species Brachionus dolabratus, Keratella tropica and Hexarthra sp. were good indicators of high turbidity due to suspended sediments. The rotifer genus Brachionus was the most species-rich taxon, comprising five species which were associated with different environmental conditions. Therefore, we tested whether this genus alone could potentially be a better biological indicator of these environmental gradients than the entire zooplankton assemblages or any other random set of five species. The ordination results show that the five Brachionus species alone did not explain better the observed pattern of environmental variation than most random sets of five species. Therefore, this genus could not be selected as a target taxon for more intensive environmental monitoring as has been previously suggested by Attayde and Bozelli (1998). Overall, our results show that changes in the water quality of man-made lakes in a tropical semi-arid region have significant effects on the structure of zooplankton assemblages that can potentially affect the functioning of these ecosystems

Influência da vermiculita expandida na resistência à compressão e reologia de pastas cimentantes de poços de petróleo

Several problems related to the loss of hydraulic seal in oilwells, causing gas migration and/or contamination of the production zone by water, have been reported. The loss of the hydraulic seal is a consequence of cracks which can be occasioned either by the invasion of gas during the wait on cement or by the expansion of the casing causing the fracture of the cement sheath. In case of the pressure of the formation is higher than the pressure in the annulus, gas can migrate into the slurry and form microannulus, which are channels where gas migrates after the cement is set. Cracks can be also occasioned by the fracture of the cement sheath when it does not withstand the thermal and dynamic loads. In reservoirs where the oil is heavy, steam water injection operation is required in order to get the oil flowing. This operation increases the temperature of the casing, and then it expands and causes the fracture of the cement sheath in the annulus. When the failures on the cement are detected, remedial cementing is required, which raise costs caused by the interventions. Once the use of cement in the construction civil sector is older than its use in the petroleum sector, it is common to bring technologies and solutions from the civil construction and apply them on the petroleum area. In this context, vermiculite, a mineral-clay widely encountered in Brazil, has been used, on its exfoliated form, in the civil construction, especially on the manufacture of lights and fireproof concretes with excellent thermal and acoustical properties. It has already been reported in scientific journals, studies of the addition of exfoliated vermiculite in Portland cements revealing good properties related to oilwell cementing operations. Thus, this study aimed to study the rheological behavior, thickening time, stability and compressive strength of the slurries made of Portland cement and exfoliated vermiculite in 5 different compositions, at room temperature and heated. The results showed that the compressive strength decreased with the addition of exfoliated vermiculite, however the values are still allowed for oiwell cementing operations. The thickening time of the slurry with no exfoliated vermiculite was 120 min and the thickening time of the slurry with 12 % of exfoliated vermiculite was 98 min. The stability and the rheological behavior of the slurries revealed that the exfoliated vermiculite absorbed water and therefore increased the viscosity of the slurries, even though increasing the factor cement-water. The stability experiment carried out at 133 ºF showed that, there was neither sedimentation nor reduction of the volume of the cement for the slurry with 12 % of exfoliated vermiculite. Thus, the addition of exfoliated vermiculite accelerates the set time of the cement and gives it a small shrinkage during the wait on cement, which are important to prevent gas migration