Analysis on the feasibility of biomass power plants adding to the electric power system – Economic,regulatory and market aspects – State of Pará, Brazil

This paper presents an analysis of the feasibility of implementing biomass power plants, through thermoelectric power generation, and adding such plants to the electric system of the local electric utility by means of independent power production. Economic, regulatory, and market issues are also addressed.The biomass being considered is produced by the lumber sector, since that is one of the industrial sectors generating the largest amount of residues in a concentrated manner in the region under study, and also considering the fact that the disposal of such residues is currently difficult for the lumber companies.The locations with the largest production of residues, as well as the size of potential plants, are identified, the generation costs of the plants calculated, and the feasibility for implementing the plants is evaluated considering the market and the regulation of the Brazilian electric power sector.     

A review of stabilization methods for DCMG with CPL, the role of bandwidth limits and droop control

DC microgrids (DCMGs) integrate and coordinate various DC distribution generation units including various renewable energy sources and battery storage systems, and have been used in satellites, the International Space Station, telecom power stations, computer power supplies, electric aircraft, and electric ships. However, the presence of constant power loads (CPLs) can cause instability in DCMGs. Thus, this paper reviews the stabilization techniques that can resolve instability caused by CPLs, as well as various parameters of CPLs, such as bandwidth, and the frequency of the CPLs that can stabilize the DCMGs. It also discusses recent trends and future work in finding stability limits using the parameters of CPLs. It should be useful for directing research towards appropriate mathematical and experimental approaches for the stability of DCMGs with CPLs.     

Long-range mapping and construction of a YAC contig within the cat eye syndrome critical region

Cat eye syndrome (CES) is typically associated with a supernumerary bisatellited marker chromosome derived from human chromosome 22pter to 22q11.2. The region of 22q duplicated in the typical CES marker chromosome extends between the centromere and locus D22S36. We have constructed a long-range restriction map of this region using pulsed-field gel electrophoresis and probes to 10 loci (11 probes). The map covers -3.6 Mb. We have also used 15 loci to construct a yeast artificial chromosome contig, which encompasses about half of the region critical to the production of the CES phenotype (centromere to D22S57). Thus, the CES critical region has been mapped and a substantial portion of it cloned in preparation for the isolation of genes in this region.     

Birthweight and blood pressure among children in Harare, Zimbabwe

AIM: To determine whether poor uterine growth may be associated with increased blood pressure and subsequent hypertension in adulthood. METHODS: A retrospective cohort study of 756 schoolchildren (mean age 6.5 years) was carried out in six low income areas in Harare city, Zimbabwe. Indices of intrauterine growth and blood pressure were assessed. RESULTS: Adjusted for current weight, the children's systolic blood pressure was inversely related to their birthweight; for each decreasing kg of birthweight, systolic blood pressure rose by 1.73 mm Hg (95% CI; 0.181 to 3.28). After adjustment for current weight, systolic blood pressure was also inversely associated with occipito-frontal circumference, but not with birth length or gestational age. Diastolic blood pressure was not associated with any of the intrauterine indices. CONCLUSION: Fetal size may be inversely related to systolic blood pressure in childhood in an African population.     

Euthanasia and physician-assisted suicide: attitudes and experiences of oncology patients, oncologists, and the public

BACKGROUND: Euthanasia and physician-assisted suicide are pressing public issues. We aimed to collect empirical data on these controversial interventions, particularly on the attitudes and experiences of oncology patients. METHODS: We interviewed, by telephone with vignette-style questions, 155 oncology patients, 355 oncologists, and 193 members of the public to assess their attitudes and experiences in relation to euthanasia and physician-assisted suicide. FINDINGS: About two thirds of oncology patients and the public found euthanasia and physician-assisted suicide acceptable for patients with unremitting pain. Oncology patients and the public found euthanasia and physician-assisted suicide least acceptable in vignettes involving "burden on the family" and "life viewed as meaningless". In no vignette--even for patients with unremitting pain--did a majority of oncologists find euthanasia or physician-assisted suicide ethically acceptable. Patients actually experiencing pain were more likely to find euthanasia or physician-assisted suicide unacceptable. More than a quarter of oncology patients had seriously thought about euthanasia or physician-assisted suicide and nearly 12 percent had seriously discussed these interventions with physicians or others. Patients with depression and psychological distress were significantly more likely to have seriously discussed euthanasia, hoarded drugs, or read Final Exit. More than half of oncologists had received requests for euthanasia or physician-assisted suicide. Nearly one in seven oncologists had carried out euthanasia or physician-assisted suicide. INTERPRETATION: Euthanasia and physician-assisted suicide are important issues in the care of terminally ill patients and while oncology patients experiencing pain are unlikely to desire these interventions patients with depression are more likely to request assistance in committing suicide. Patients who request such an intervention should be evaluated and, where appropriate, treated for depression before euthanasia can be discussed seriously.     

Application of the Fuzzy Logic for the Development of Automnomous Robot with Obstacles Deviation

International Journal of Control, Automation and Systems - This paper proposed to elaborate a navigation system for an autonomous mobile robot, able to deviate from obstacles, from the study and...     

Triplet EPR Dynamics of Randomly Oriented Dications and Dianions of Tetraoxaporphyrinoids

This paper deals with the photoexcited triplet state of several tetraoxaporphyrinoids studied by time-resolved electron paramagnetic resonance (EPR). The porphyrinoids studied are tetraoxa[18]porphyrin ( 1a ⁺⁺), octaethyl-tetraoxa[18]porphyrin ( 1b ⁺⁺), tetra-n-butyl tetraoxa[18]porphyrin ( 1c ⁺⁺), octaethyl-tetraoxa[26]porphyrin ( 2 ⁺⁺), and tetraoxa[18]porphycene ( 3 ⁺⁺), all of them as per-chlorate salts. To qualify as stable aromatic 18π- (or 26π-) electron systems, they must exist as dications. Analysis of the triplet EPR spectra is characterized by unique features not found in their parent porphyrins and porphycenes. While in the case of the axially-symmetric tetraphenylporphyrin, the triplet EPR spectra indicate deviation from axial symmetry, the tetraoxaporphyrin 1a ⁺⁺ exhibits, as expected, a vanishing E-term of the zero-field splitting (ZFS) tensor. A conspicuous difference is found between the triplet EPR spectra of the dications and the dianions of all tetraoxa compounds. The results are discussed in terms of the electronic structures of the porphyrinoids.     

High-temperature phase and microstructure evolution of polymer-derived SiZrCN and SiZrBCN ceramic nanocomposites

A zirconium and a zirconium/boron containing single-source precursor were synthesized via chemical modification of a commercially available polysilazane (Durazane 1800) with tetrakis (dimethylamido) zirconium (IV) (TDMAZ) as well as with both TDMAZ and borane dimethyl sulfide complex, respectively. The polymer-to-ceramic transformation of the precursors into SiZrCN and SiZrBCN ceramics as well as the thermal evolution of their phase composition and microstructure was studied. The pyrolysis of the precursors led to the formation of amorphous SiZrCN and SiZrBCN ceramics. Interestingly, the as prepared SiZrBCN ceramic was single-phasic and fully featureless; whereas SiZrCN exhibited the presence of nano-sized ZrO₂ particles; however, only very localized in close proximity to internal surfaces. Heat treatment at higher temperatures induced crystallization processes in both prepared ceramics. Thus, at temperatures beyond 1500°C, cubic ZrC_xN_y, β-Si₃N₄ as well as β-SiC were generated. It was shown that the incorporation of B into SiZrCN suppressed the crystallization of ZrC_xN_y and, in addition, impeded the reaction of SiN_x with C, resulting in an improved thermal stability of SiZrBCN compared to SiZrCN ceramic. Moreover boron was shown to be mainly located in the sp²-hybridized “free” carbon present in SiZrBCN, forming a turbostratic BCN phase which has been unequivocally detected by means of high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDS).     

Additive-Enhanced Redispersion of Ceramic Agglomerates

Deagglomeration of ceramic powders is usually accomplished by immersion of powders in a surfactant-containing liquid vehicle, followed by milling. We seek alternative mechanisms to the classical milling approach by generating a chemical pressure to break up the agglomerate. This study explores the enhanced redispersion of TiO₂ ceramic compacts that contain a nonionic water-soluble polymer, poly(ethylene glycol) (PEG). PEG forms a polymer solution within the agglomerated structure during redispersion. The resulting osmotic pressure gradient forces water into the porous structure and creates a tensile stress on the particle network with magnitudes as high as 0.6 MPa. Thus, the principle to achieving redispersion is to develop osmotic pressures that exceed the cohesive strength of the agglomerated structure. A critical PEG concentration of 2.0 vol% PEG 400 with respect to titania has been determined, below which redispersion is minimal.