LARGE MINERAL ACTIVITY: A SOCIAL, ECONOMIC AND ENVIRONMENTAL APPROACH THROUGH GEOTECHNOLOGIES

Mining is one of the most important economic activities in Goiás, and it is necessary for the municipalities. The abundance of some mineral substances in the state makes Goiás a desirable location for large extraction companies. This research paper outlines that landscape alteration is inevitable, as it is necessary to remove natural areas for the exploitation of minerals. Agricultural areas could be effected by this process. This paper is discussing a evolution of mining activity that was done with the corporation of Alto Horizonte between 1985 and 2015, observing intervals of a decade, and relating this change to the socio-economic data of the municipality. Remote sensing techniques were used in conjunction with Geographic Information System (GIS), two such techniques include: satellite, image classification and data from socioeconomic surveys. Which provided the basis for relating them to the information generated by the mappings. Through quantitative analysis and visual observations of the mappings of the enterprise and its surroundings, it was possible to notice the modification of the landscape. In addition, socioeconomic data could indicate the influence that mining has had on Alto Horizonte. Although the enterprise has a high industrial mineral production and raise the city's GDP, it is not invested in better wages for the population, ie, workers' income does not keep up with the minimum wage increase.

Several erosion test results of means of sand control

When screens are used as the sole means of sand control, they function as a downhole filter. The entry of sand or other particles into horizontal and vertical wells presents the problem of steel erosion and productivity lost. Downhole is the most desirable location to restrict its access into the well. The problem of material reliability testing is relevant today, that’s why several erosion tests were made and studied. Self-made test bench allow varying velocity flow and fractions conditions (composition, quantity, size, hardness). Slurry erosion experiments resulted in wear of downhole sand control screens. The wear criteria were checked by weight loss of screen samples material and its integrity degradation. The idea of slurry erosion tests was to reveal screens wear.

Selectively Nucleated Lateral Crystallization for a Large Single-Grained Pb(Zr,Ti)O3 on Polycrystalline-Silicon Thin-Film Transistors for System-On-Glass Applications

ABSTRACTA single-grained Pb(Zr,Ti)O3 (PZT) was successfully grown for the gate dielectric of polycrystalline-silicon (poly-Si) thin-film transistor (TFT). The total structure was MoW/PZT/HfO2/poly-Si/glass. The giant single-grained PZT was obtained by controlling the artificial nucleation formed by Pt dots in a desirable location and enlarging the nucleated seed until it covers the poly-Si channel. The single-grained diameter size was 40 μm with a (100) dominated texture. The poly-Si memory device with single-grained PZT showed an excellent ferroelectric, electrical and reliability properties comparing with poly-Si memory device with poly-grained PZT. Moreover, eliminating the grain boundary in PZT film showed the fatigue and retention characteristics with only 1.1 % after 1013 cycles and 22 % after 1 month, respectively.

Persistence of Complex Virulences in Populations of Phytophthora infestans in Western Washington

Isolates of Phytophthora infestans, collected from bittersweet, hairy nightshade, petunia, potato, potato vine, and tomato in western Washington, 1998 to 1999, were evaluated for virulence complexity as well as mating type, metalaxyl insensitivity, allozymes of glucose-6-phosphate isomerase and peptidase, and DNA fingerprint with the RG57 probe. Results were compared with those from similar collections made in the same region during the 1990s. Generally, virulence complexity was high for most of the isolates regardless of year, genotype, or host. No marked shift in virulence complexity was evident for the populations studied, and unnecessary virulences were maintained. During 1998 and 1999, isolates of the US-8 and US-11 genotypes had 4 or more virulence factors. US-8 isolates averaged 8.2 and 9.3, whereas US-11 isolates averaged 5.4 and 6.3 virulence factors. The frequency of US-8 isolates that were sensitive to metalaxyl ranged from 5% in 1998 to 72% in 1999. All of the US-11 isolates tested in 1998 and 1999 were insensitive to metalaxyl. From 1996 to 1999 on potato, the recovery of US-8 increased, whereas the recovery of US-11 decreased. No evidence of new genotypes or sexual recombination was found. Western Washington was a desirable location for screening germ plasm for durable resistance to late blight due to the high frequency and persistence of complex virulences.

DELAYED CONTROL OF A MOORE–GREITZER AXIAL COMPRESSOR MODEL

Several feedback control laws have appeared in the literature concerning the stabilization of the nonlinear Moore–Greitzer axial compression model. Motivated by magnitude and rate limitations imposed by the physical implementation of the control law, Larsen et al. studied a dynamic implementation of the S-controller suggested by Sepulchre and Kokotović. They showed the potential benefit of implementing the S-controller through a first-order lag: while the location of the closed-loop equilibrium achieved with the static control law was sensitive to poorly known parameters, the dynamic implementation resulted in a small limit cycle at a very desirable location, insensitive to parameter variations. In this paper, we investigate the more general case when the control is applied with a time delay. This can be seen as an extension of the model with a first-order lag. The delay can either be a result of system constraints or be deliberately implemented to achieve better system behavior. The resulting closed-loop system is a set of parameter-dependent delay differential equations. Numerical bifurcation analysis is used to study this model and investigate whether the positive results obtained for the first-order model persist, even for larger values of the delay.