The structural, transport and optical properties of screen printed CuxS thick films

The structural, transport and optical properties of screen printed CuxS thick films with possible application in photovoltaic and photothermal devices are reported. The X-ray diffraction studies show that the screen printed films are stable up to about 220°C in air and belong to the CuxS structure. Above this temperature it decomposes mainly to CuSO₄. The electrical conductivity depends on the sintering temperature and the amount of flux, Cu(NO₃)₂, used in the paste for screen printing. The differential scanning calorimetry studies reveal the phase changes occurring during heating and pertaining to the dependence of electrical conductivity on the sintering temperature. A configuration consisting of screen printed CuxS on chemically deposited and annealed (at 200°C) CdS thin film exhibited rectification.     

Computing the Value of a Boolean Expression with Interval Inputs is NP-Hard

To make an expert system work, we must store the statements that comprise expert knowledge. These statements usually have a degree of uncertainty associated with them, and these degrees of uncertainty are naturally described by intervals (sub-intervals of the interval [0, 1]). When we ask a query that is a logical combination of the statements stored in the system, we must, therefore, use interval computations to compute its resulting degree of certainty. In this paper, we prove that in general, computing these degrees of belief is intractable (NP-hard).     

Preparation and characterization of novel grafted polyethylene based azo-polymers bearing oligo(ethylene glycol) spacers

Novel grafted azo-polymers were prepared from commercial low density polyethylene plates (PE). First, precursor polymers were synthesized by reacting PE in the presence of acryloyl chloride using gamma radiation. Further esterification of the resulting grafted polymers with four new amino-nitro substituted azobenzene derivatives bearing oligo(ethylene glycol) segments: N-methyl-N-{4-[(E)-(4-nitrophenyl)diazenyl]phenyl}-N-(5-hydroxy-3-oxapentas-1-yl)amine (RED-PEG-2), N-methyl-N-{4-[(E)-(4-nitrophenyl)diazenyl]phenyl}-N-(8-hydroxy-3,6-dioxaoctas-1-yl)amine (RED-PEG-3), N-methyl-N-{4-[(E)-(4-nitrophenyl)diazenyl]phenyl}-N-(11-hydroxy-3,6,9-trioxaundecas-1-yl)amine (RED-PEG-4) and N-methyl-N-{4-[(E)-(4-nitrophenyl)diazenyl]phenyl}-N-(17-hydroxy-3,6,9,12,15-pentaoxaheptadecas-1-yl)amine (RED-PEG-6) led to the formation of branched azo-polymers. These polymers were characterized and their thermal and optical properties were studied. Besides, the influence of the irradiation dose, irradiation time and the structure of the dyes on the properties of the obtained polymers are discussed.     

Dynamic Lean Management of the Naval Construction Process

Abstract:

The naval and private construction industries face shared problems in regard to cost over-runs and delays that may be addressed in part through improvements to the construction process. The scope of this study is to examine the naval construction process from design to implementation, with special emphasis on the role of design sharing and constructability. We use the System Dynamics methodology to model the construction process and conduct simulations to examine the impact of project management decisions. We conclude that increased constructability efforts and design sharing mitigate the impact of cost over-runs and project completion delays, and that when limited resources exist it is best to focus improvement efforts early rather than later.     

Management of the sulfur content in the gasoline transport logistics chain in a multi-product pipeline

Abstract

The authors’ objective is to manage sulfur content in gasoline over a multi-product pipeline using data derived from a correlation study. Sulfur content is analyzed by ultraviolet fluorescence or monochromatic wavelength dispersive X-ray fluorescence spectrometry in three different sampling points by three laboratories. At the same time, this study evaluates the homogeneity between laboratories/methods and if the analytical results of data vary in different sampling points of the pipeline. By means of two-way analysis of variance with interaction, the results show that there are variations along the multi-product pipeline besides differences between methods and laboratories.     

Structure of a galactoarabinoglucuronoxylan from tamarillo (Solanum betaceum), a tropical exotic fruit,and its biological activity

Tamarillo (Solanum betaceum) is a tropical exotic fruit whose polysaccharides were extracted from the ripe pulp. After various purification steps, homogeneous fractions (designated PTW, STK-1000R and PF) were analyzed by sugar composition, HPSEC, methylation and NMR spectroscopy analysis. The results showed that the fraction PTW consisted of a linear arabinan with (1 → 5)-linked α-l-arabinofuranosyl units. Fractions designated as STK-1000R and PF contained galactoarabinoglucuronoxylans, with (1 → 4)-linked β-d-Xylp residues in the backbone, carrying branches exclusively at O-2. The polysaccharide in STK-1000R is less branched than that in the PF fraction (∼20.0% and 36.5%, respectively), with side-chains formed by (1 → 5)-linked α-l-Araf residues and (1 → 4)-linked α-d-GlcpA residues and with non-reducing end units formed by α-l-Araf, β-Arap, β-d-Galp, α-d-GlcpA and 4-O-Me-α-d-GlcpA. Intraperitoneal administration of the STK-1000R fraction in mice significantly reduced the number of abdominal constrictions induced by 0.6% acetic acid and the inflammatory phase of nociception induced by 2.5% formalin, indicating that that fraction has an antinociceptive effect on inflammatory pain models.     

Multivariate analysis for the differentiation of sparkling wines elaborated from autochthonous Spanish grape varieties: volatile compounds, amino acids and biogenic amines

The aim of this work was to focus on the study of the volatile composition of white and rosé base wines elaborated from different autochthonous grape varieties in Spain (Verdejo, Viura, Malvasía, Albarín, Godello, Prieto Picudo and Garnacha) and the evolution of the sparkling wines elaborated from them following the “champenoise” method. The amino acids and biogenic amines were also studied. Multivariate analyses (factorial and stepwise discriminant) were carried out to study the influence of these compounds all together. Base and sparkling wines from Albarín, Verdejo, Godello and Prieto Picudo were the richest in most of the volatile compounds analyzed, especially of ethyl esters and alcohol acetates, compounds that contribute to the fruity aroma of wines. During the aging on lees in the bottle of sparkling wines, an increase in branched ethyl esters, ethyl lactate and γ-butyrolactone, and a decrease in terpenes (mainly citronellol and geraniol) were observed. In general, the levels of biogenic amines in all the sparkling wines studied were very low, which does not represent a negative effect on their quality and safety.     

Photocatalytic hydrogen evolution over the isostructural titanates: Ba3Li2Ti8O20 and Na2Ti6O13 modified with metal oxide nanoparticles

Isostructural titanates exhibiting rectangular tunnel structure with the general formula Na₂Ti₆O₁₃ and Ba₃Li₂Ti₈O₂₀, were synthesized by solid state and sol-gel methods. The structural, morphological, optical, textural and electrical properties of the materials were characterized by XRD, SEM, UV-vis, BET and EIS. The photocatalytic activity for hydrogen evolution of the materials was evaluated under UV light. Na₂Ti₆O₁₃ exhibited higher activity (120 μmol/gh) than Ba₃Li₂Ti₈O₂₀ (30 μmol/gh), and it was attributed to the distortion of the octahedrons in Ba₃Li₂Ti₈O₂₀, which increases the recombination of charges in the material. Additionally, the 1D dimension obtained in Na₂Ti₆O₁₃ promotes a better charge separation, transport and utilization in this phase. The activity of the materials was enhanced with the incorporation of metal oxide nanoparticles MO (M = Cu, Ni) as cocatalysts. The activity of Ba₃Li₂Ti₈O₂₀ increased 10 times with the addition of CuO (240 μmol/gh), while the activity of Na₂Ti₆O₁₃ increased 3.5 times (416 μmol/gh). This improvement in the photocatalytic activity of the isostructural titanates was attributed to the formation of a p-n heterostructure between n-type titanates and p-type CuO, which promoted an enhanced charge separation, transference and utilization.