CO-gasification of pelletized wood residues

A pelletization process was designed which produces cylindrical pellets ∼8 mm in length and 4 mm in diameter. These ones were manufactured using a blend of Pinus Patula and Cypress sawdust and coal in proportions of 0%, 5%, 10%, 20%, and 30% v/v of coal of rank sub-bituminous extracted from the Nechí mine (Amagá-Antioquia). For this procedure, sodium carboxymethyl cellulose (CMC) was used as binder at three different concentrations. The co-gasification experiments were carried out with two kinds of mixtures, the first one was composed of granular coal and pellets of 100% wood and the second one was composed of pulverized wood and granular coal pellets. All samples were co-gasified with steam by using an electrical heated fluidized-bed reactor, operating in batches, at 850 °C. The main components of the gaseous product were H₂, CO, CO₂, CH₄, and N₂ with approximate quantities of 59%, 6.0%, 20%, 5.0%, and 9.0% v/v, respectively, and the higher heating values ranged from between 7.1 and 9.5 MJ/Nm³.     

A review of instance selection methods

In supervised learning, a training set providing previously known information is used to classify new instances. Commonly, several instances are stored in the training set but some of them are not useful for classifying therefore it is possible to get acceptable classification rates ignoring non useful cases; this process is known as instance selection. Through instance selection the training set is reduced which allows reducing runtimes in the classification and/or training stages of classifiers. This work is focused on presenting a survey of the main instance selection methods reported in the literature.     

Within- and between-language priming differ: Evidence from repetition of pictures in Spanish-English bilinguals.

In the current study, the authors used an immediate repetition paradigm with pictures to observe whether repetition enhances word production in bilinguals. In Experiment 1, participants were asked to name pictures that were named previously in the same language (Spanish-Spanish or English-English) or in the opposite language (Spanish-English or English-Spanish). Results revealed a repetition effect both within languages and between languages. Furthermore, there was an asymmetry within language, with repetition priming being larger in Spanish than in English. Experiments 2 and 3 revealed that lag interacted with language for both within- and between-language priming. However, lag resulted in a decrease in the asymmetry for within- but not between-language priming. The results are consistent with the view that within- and between-language repetition priming are mediated by different mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An Evaluation of Vaporizing Rates of SiO2 and TiO2 As Protective Coatings for Ultrahigh Temperature Ceramic Composites

For temperatures >1973 K, the thermodynamic and kinetic analyses of the major gaseous species for a liquid titanate layer would vaporize significantly less than a silicate layer, when considering these layers as a protective barrier for ultrahigh temperature ceramic composites. At 2500 K, the major species is TiO( g ) with p _{TiO( g )}=0.1 kPa compared with SiO( g ) with p _{SiO( g )}=1.3 × 10³ kPa at the Ti/TiO₂ and Si/SiO₂ equilibrium, respectively. The SiO( g ) attains a partial pressure greater than ambient pressure at 2500 K even with a thermodynamic activity of 0.01 considering equilibration with a silicide (e.g., TiSi _x ). In addition, at 2500 K the TiO₂ layer would vaporize at a rate of 0.23 mm/s compared with the SiO₂ layer's loss rate of 207 mm/s. Although the oxygen diffusivity and permeability through titanate solutions must be further analyzed, the thermodynamic and kinetic analyses for vaporization indicate a longer duration for a liquid titanate than for a liquid silicate layer at ultrahigh temperatures.     

High-Temperature Plastic Behavior of TZP–Ni Cermets

The creep behavior of tetragonal zirconia TZP–Ni cermets with metal contents below, close to, and above the percolation limit has been studied. Compressive creep tests were performed on as-received materials and samples in which the metal phase was chemically removed (ceramic skeletons). The stress exponent and the activation energy for plastic flow are independent of the nickel content and decrease continuously on increasing the stress and/or the temperature; skeleton structures display the same trend, suggesting that creep is controlled by the zirconia matrix. The steady-state constitutive equation for high-purity monolithic zirconia applies to the cermets when the stress is corrected with the porosity and volume fraction of percolated nickel.     

Power quality analysis of 6 kW building-integrated photovoltaic system and economic evaluation using RETScreen™

This paper describes the power quality analysis applied on 6?kW building-integrated photovoltaic system (BIPVS) and its economic study. A monitoring system was implemented using virtual instrumentation to measure irradiance, ambient temperature and electric variables of the photovoltaic (PV) system. The study includes a period of one year from September 2015 to August 2016 and for this the IEEE 929-2000 standard guidelines were followed. The results indicate that the power quality parameters: % THDv, frequency, nominal voltage and flicker meet the standard limits mentioned. Economic analysis of the PV system using the RETScreen? software is also presented. The results show a net present value of USD 35,157 for a period of 20 years with an annual energy saving of USD 1750. Greenhouse gas emissions avoided by the use of solar energy are 6.6 t CO₂ per year.     

Coupling hydrothermal liquefaction and aqueous phase reforming for integrated production of biocrude and renewable H2

Lignin-rich stream from lignocellulosic ethanol production was converted into biocrude by continuous hydrothermal liquefaction (HTL) while hydrogen was produced by aqueous phase reforming (APR) of the HTL aqueous by-product. The effects of Na₂CO₃ and NaOH were investigated both in terms of processability of the feedstock as well as yield and composition of the obtained products. A maximum biocrude yield of 27 wt% was reached in the NaOH-catalyzed runs. A relevant amount of dissolved phenolics were detected in the co-produced aqueous phase (AP), and removed by liquid–liquid extraction using butyl acetate or diethyl ether, preserving the APR catalyst stability and reaching an hydrogen yield up to 146 mmol H₂ L⁻¹ AP. Preliminary mass balances integrating HTL and APR showed that the hydrogen provided by APR may account for up to 46% of the hydrogen amount theoretically required for upgrading the HTL biocrude, thus significantly improving the process performance and sustainability.     

Plastic deformation of dense nanocrystalline yttrium oxide at elevated temperatures

Nanocrystalline yttrium oxide, Y₂O₃ with 110 nm average grain size was plastically deformed between 800 °C and 1100 °C by compression at different strain rates and by creep at different stresses. The onset temperature for plasticity was at 1000 °C. Yield stress was strongly temperature dependent and the strain hardening disappeared at 1100 °C. The polyhedral and equiaxed grain morphology were preserved in the deformed specimens. The experimentally measured and theoretically calculated stress exponent n = 2 was consistent with the plastic deformation by grain boundary sliding. Decrease in the grain size was consistent with decrease in the brittle to ductile transition temperature.     

Diosgenin quantification,characterisation and chemical composition in a tuber collection of Dioscorea spp. in the state of Jalisco,Mexico

Dioscorea spp. tubers are known commonly as camote de cerro to the state of Jalisco, México. Besides its use as food, it contains diosgenin, a raw material used widely for synthesising steroid hormones. The purpose of the present research was to determine diosgenin contents by gas chromatography‐mass spectrometry (GC‐MS), as well as physical and chemical characteristics of sixty Dioscorea spp. accessions cultivated in mesh shade coming from eleven localities in the state of Jalisco. Extraction protocol for diosgenin was maceration combined with ethanol 80%. Significant statistical differences for diosgenin content were found between accessions, finding levels between 0.02 and 0.16 mg kg^?1 in dry basis. Length, weight tuber, proportion pulp/skin, percentage of pulp and percentage of skin showed significant differences. Chemical composition based in fresh weight presented in moisture percentage a range of 71.93–83.26%, crude protein 1.42–1.74%, ashes 0.80–1.16%, lipid 0.13–0.17%, crude fibre 3.80–4.02% and total carbohydrates 13.97–25.44%. Results show that tubers from Jalisco can be an important source of nutrients for consumers.