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.     

Assessment of the probiotic potential of lactic acid bacteria isolated from Minas artisanal cheese produced in the Campo das Vertentes region,Brazil

The microbiota of the Brazilian Minas artisanal cheese, made from raw milk, is not well known and may include probiotic bacteria. This study aimed to assess the in vitro and in vivo probiotic properties of the lactic acid bacteria isolated from these cheeses. Thirty‐six samples of the Lactobacillus/Pediococcus group were selected for in vitro investigation. Pediococcus acidilactici (PA2) and Lactobacillus plantarum (LP4) showed the best results and were tested for their ability to protect Salmonella Typhimurium orally infected mice. LP4 showed better probiotic potential than PA2 and allowed higher values of weight gain (P < 0.05). Thus, Lb. plantarumLP4 may have potential use as a probiotic in foods after future technological screening.     

The Importance of Polarity in the Evolution of the K+ Binding Site of Pyruvate Kinase

In a previous phylogenetic study of the family of pyruvate kinase, we found one cluster with Glu117 and another with Lys117. Those sequences with Glu117 have Thr113 and are K⁺-dependent, whereas those with Lys117 have Leu113 and are K⁺-independent. The carbonyl oxygen of Thr113 is one of the residues that coordinate K⁺ in the active site. Even though the side chain of Thr113 does not participate in binding K⁺, the strict co-evolution between position 117 and 113 suggests that T113 may be the result of the evolutionary pressure to maintain the selectivity of pyruvate kinase activity for K⁺. Thus, we explored if the replacement of Thr113 by Leu alters the characteristics of the K⁺ binding site. We found that the polarity of the residue 113 is central in the partition of K⁺ into its site and that the substitution of Thr for Leu changes the ion selectivity for the monovalent cation with minor changes in the binding of the substrates. Therefore, Thr113 is instrumental in the selectivity of pyruvate kinase for K⁺.