Procedimento de operação, manutenção e verificação de thermomixer.

bitstream/CENARGEN/29576/1/ct060.pd

Procedimento de operação, manutenção e verificação da centrífuga refrigerada de bancada Eppendorf, Modelo 5810 R.

bitstream/CENARGEN/29583/1/ct063.pd

Procedimento de operação, manutenção e verificação da estufa ELETROLAB modelo 112FC.

bitstream/CENARGEN/29586/1/ct065.pd

Procedimento de operação, manutenção e verificação do Espectrofotômetro.

bitstream/CENARGEN/29588/1/ct067.pd

Inducing energy gaps in graphene monolayer and bilayer

In this paper we propose a mechanism for the induction of energy gaps in the spectrum of graphene and its bilayer, when both these materials are covered with water and ammonia molecules. The energy gaps obtained are within the range 20-30 meV, values compatible to those found in experimental studies of graphene bilayer. We further show that the binding energies are large enough for the adsorption of the molecules to be maintained even at room temperature

Low-complexity Multidimensional DCT Approximations

In this paper, we introduce low-complexity multidimensional discrete cosine transform (DCT) approximations. Three dimensional DCT (3D DCT) approximations are formalized in terms of high-order tensor theory. The formulation is extended to higher dimensions with arbitrary lengths. Several multiplierless $8\times 8\times 8$ approximate methods are proposed and the computational complexity is discussed for the general multidimensional case. The proposed methods complexity cost was assessed, presenting considerably lower arithmetic operations when compared with the exact 3D DCT. The proposed approximations were embedded into 3D DCT-based video coding scheme and a modified quantization step was introduced. The simulation results showed that the approximate 3D DCT coding methods offer almost identical output visual quality when compared with exact 3D DCT scheme. The proposed 3D approximations were also employed as a tool for visual tracking. The approximate 3D DCT-based proposed system performs similarly to the original exact 3D DCT-based method. In general, the suggested methods showed competitive performance at a considerably lower computational cost.Comment: 28 pages, 5 figures, 5 table

Nitrogen fertilization management in no-tillage maize with different witer crops.

The nitrogen (N) utilization by maize grown in a no-tillage system is dependent on the quality of the preceding crop residues, which may promote differences in N fertilization efficiency with respect to time. Thus, the purpose of this study was to evaluate the nutritional state, dry matter production and grain yield of maize grown in a clayey soil (Typic Acrustox) under a no-tillage system. The split-plot experimental design was set up in randomized complete blocks with three replications, in which the main plot was treated with different N application strategies and the split-plots were planted with winter crops (soybean and maize). The fertilizer strategies (rate: 120 kg ha-1 of N) used were as follows: (0 ? 0), (20 ? 100), (60 ? 60), (120 ? 0) and (0 ? 120), with the first number corresponding to the rate of N (kg ha-1) applied before planting and the second number corresponding to the top dressing rate (V4-5 stage). Nitrogen fertilization raised the N content (in shoots and leaves) and maize yield (in the shoot dry matter and grain). The maize grown after soybean had both greater N concentrations and production (dry matter and grain) relative to the maize grown after maize. Applying 120 kg ha-1 N did not significantly affect the evaluated variables, regardless of the winter crop

Eficácia de Misturas de Fungicidas Químicos na Micobiota e na Qualidade Fisiológica de Sementes de Mamoneira.

bitstream/item/60716/1/BOLPES91.pd

Ab initio modeling of defects in silicon, germanium and SiGe alloys

Understanding the most elemental defects in semiconductors is a fundamental step to grasp the countless solid-state reactions that may occur during crystal growth, device processing and operation stages. The higher carrier mobilitity in SiGe alloys and germanium, when compared with silicon, and the necessity to a higher K dielectric than SiO2 makes these semiconductors the most contendors to a new generation of electronic devices. Our aim is to model self and impurity point defects in SiGe alloys and germanium, and compare with their equivalent complexes in silicon. We use density functional theory and pseudopotentials to determine the structural, electronic and vibrational properties. The calculations are performed in a 32 CPU PC cluster, in Physics Department of Aveiro University.Fundação para a Ciência e a Tecnologia (FCT).INTAS