Application of a multicriteria methodology for evaluation of energy alternatives for hydrogen production for the automotive sector – Case study

This paper presents a case study focusing on fourteen most used energy alternatives in Brazil, possible to feed large scale hydrogen production plants for the automotive sector. The evaluations are made using a Decision Making Support Method, MACBETH - Measuring Attractiveness by a Categorical Based Evaluation Technique, with the computational code M-MACBETH 3.2.0, using criteria that include economic and financial, technological, environmental and social aspects. The selected criteria that were used in the assessment, for each of the energy alternatives are capital to be invested in a plant, leveled cost of electric energy produced, CO₂ emissions, mortality rate due to the technology use and energy efficiency of technology. The main results obtained showed that photovoltaics off grid electric energy is the most attractive alternative, followed by the photovoltaic on grid alternative, for an eventual automotive hydrogen program in Brazil.     

A decomposition-based approach for the selection of standardized modular containers

The standardisation of packaging and containers for product handling has potential benefits from transportation, material handling and environmental perspectives. Likewise, standardised modular containers play an important role in the Physical Internet (PI). To support implementation of standard modular containers, we introduce a mathematical model to select a requisite number of modular containers to pack a set of products to maximise space utilisation. A decomposition-based solution methodology is developed and presented. Computational results from industry-based problem instances indicate that using standardised modular containers results in increased space utilisation at the unit load level. This finding substantiates the use of modular containers in moving toward the PI.     

On the Delay of a CNTFET with Undeposited CNTs by Gate Width Adjustment

This paper deals with the performance of a Carbon Nano Tube Field Effect Transistor (CNTFET) in the presence of undeposited CNTs as defects. A simulation-based analysis of delay degradation due to different features (such as chirality and defective CNT distribution) is initially pursued. Two solutions to mitigate the change in delay are proposed; these approaches are based on adjusting the gate width of the CNTFET by lithography (and removing CNTs) as part of the fabrication process. These two methods reduce the average delay and its deviation, respectively. A probabilistic delay analysis is then presented. The performance of the proposed two adjustment methods is evaluated by considering CNT features (such as chirality and defect distribution) deterministically and probabilistically. By deterministic (probabilistic) simulation, the first method reduces on average the delay by 6.968 % (7.811 %) while the deviation is increased (decreased) by 32.444 % (9.788 %). The second method reduces deterministically (probabilistically) on average the deviation by 44.159 % (47.476 %) with 2.166 % (4.409 %) delay reduction.     

A neutronic evaluation of the (Pu–U) and (Am–Pu–U) insertion in a typical fuel of Angra-I

The goal is to evaluate the neutronic behavior when (Pu–U) and (Am–Pu–U) mixed oxide are inserted in a typical cell of a Pressurized Water Reactor (PWR) such as Angra-I. Four types of fuels were studied: (1) MOX fuel enriched at 3.1% and V_m/V_f = 1.15; (2) MOX fuel enriched at 4.5% and V_m/V_f = 1.15; (3) MOX fuel enriched at 4.5% and V_m/V_f = 2.0 and (4) MOX fuel enriched at 4.5%, with 1% of Americium insertion in its composition (62.8% of Am²⁴¹, 0.1% of Am^242m and 37.1% of Am²⁴³) and with V_m/V_f = 2.0. The first case represents the standard state of Angra I, but with Pu. The second case is similar to the first but the enrichment is increased. To evaluate the Americium insertion, a study of the V_m/V_f was made and better results were obtained with V_m/V_f = 2.0 and to compare, this case was too evaluated to (Pu–U) in the third and fourth cases. The idea is to verify the possibility of using these fuels in Angra-I analyzing neutronic parameters such as infinite multiplication factor, hardening spectrum, Boron worth and reactivity temperature coefficients. The results show that it is possible to use all the studied fuels in Angra-I as well as to burn Am inserted in the MOX fuel by a considerable quantity during PWR operation. The WIMS-D5 code was used to perform a simplified neutronic and burnup simulations to evaluate this possibility.     

Indirect estimation of elliptical stable distributions

An indirect estimation approach for elliptical stable distributions is presented. The auxiliary model is another elliptical distribution, the multivariate Student-t distribution. It has parameters that have a one-to-one relationship with those of the elliptical stable, making the proposed indirect approach particularly suitable. The finite sample behaviour of the estimators is analyzed using a comprehensive Monte Carlo study. An application to 27 emerging markets stock indexes concludes the paper.     

F-substituted hydroxyapatite nanopowders: Thermal stability,sintering behaviour and mechanical properties

Fluorine-substituted hydroxyapatites are considered promising materials for bone scaffolding. In this study a systematic investigation on F-half substituted hydroxyapatite (F-HAp, Ca₁₀(PO₄)₆OHF) obtained by precipitation is reported. Results on composition analysis, thermal behaviour, and sinterability are presented for a comparison with the respective pure hydroxyapatite. Samples were characterised by electron microscopy, induced coupled plasma-atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N₂ adsorption measurements, X-ray diffraction and dilatometry. A semicrystalline F-substituted hydroxyapatite powder made up of needle-like nanoparticles was obtained. Notwithstanding that it was thermally stable up to 1300 °C, it was sintered at relatively low temperatures obtaining a very fine microstructure with a relevant nano-porosity, beneficial in view of cell adhesion and in-growth.Hardness, elastic modulus and toughness of produced samples were investigated by Vickers–Knoop microhardness testing. Significant improvements of the mechanical properties were observed for the F-substituted hydroxyapatite, in comparison with pure hydroxyapatite.     

Valyl-transfer RNA formation stimulated by monovalent cations and spermine in rat liver

The effects of hypothalamic disconnection on body temperature and hypothalamo-pituitary-adrenal activity following acute and repeated exposures to heat were studied. Intact male rats, or animals with complete posterior or anterior hypothalamic disconnection, were exposed to a temperature of 36 degrees C and a relative humidity of 35-45%. In the complete posterior and anterior hypothalamic disconnected rats the basal Tre was higher than that of the intact rats; the rise in Tre following heat exposure was lower in the operated rats than in the intact animals. All the experimental animals, except for those with anterior hypothalamic disconnection, showed a significant inhibition of corticosterone release on exposure to heat for 30 min, but no inhibition was observed in any of the disconnected rats when they were exposed to heat for 120 min. These results suggest that the main stimulus for ACTH release, during the first 30 min of heat exposure, is mediated by a neural input through the posteroir hypothalamus and this is followed by a nerural and/or humoral mechanism which enables the animals to increase their corticosterone secretion.     

Availability analysis of a N modules parallel system with common memory,central controller and distributed software

Parallel systems with processing distributed in the various modules are very interesting examples of hardware/software tradeoffs within a complex structure. An example of such a system mode of N modules, has been considered. The implications of a common memory and a central controller are analysed and an availability model is derived.The division of the software task into subtasks is viewed as a source of possible deadlock of the structure. Series catastrophic states due to hard core units and software coupling are included in the availability analysis.     

Phenotypic and genetic diversity of enterococci isolated from Italian cheeses

In the present study, 124 enterococcal strains, isolated from traditional Italian cow, goat and buffalo cheeses, were characterized using phenotypic features and randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). The RAPD-PCR profiles obtained with four primers and five different amplification conditions were compared by numerical analysis and allowed an inter- and intraspecific differentiation of the isolates. Whole cell protein analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used as a reference method for species identification. The strains were identified as Enterococcus faecalis (82 strains), E. faecium (27 strains), E. durans (nine strains), E. gallinarum (four strains) and E. hirae (two strains). Species recognition by means of RAPD-PCR was in agreement with the SDS-PAGE results except for eight strains of E. faecium that clustered in separated groups. On the other hand, phenotypic identification based on carbohydrate fermentation profiles, using the rapid ID 32 STREP galleries, gave different results from SDS-PAGE in 12.1% of the cases. The majority of the strains had weak acidifying and proteolytic activities in milk. One E. faecium strain showed vanA (vancomycin resistance) genotype while four strains showed a beta-haemolytic reaction on human blood. Several strains showed antagonistic activity towards indicator strains of Listeria innocua, Clostridium tyrobutyricam and Propionibacterium freudenreichii subsp. shermanii.