Parametric Analysis of a Two-Shaft Aeroderivate Gas Turbine of 11.86 MW

The aeroderivate gas turbines are widely used for power generation in the oil and gas industry. In offshore marine platforms, the aeroderivative gas turbines provide the energy required to drive mechanically compressors, pumps and electric generators. Therefore, the study of the performance of aeroderivate gas turbines based on a parametric analysis is relevant to carry out a diagnostic of the engine, which can lead to operational as well as predictive and/or corrective maintenance actions. This work presents a methodology based on the exergetic analysis to estimate the irrevesibilities and exergetic efficiencies of the main components of a two-shaft aeroderivate gas turbine. The studied engine is the Solar Turbine Mars 100, which is rated to provide 11.86 MW. In this engine, the air is compressed in an axial compressor achieving a pressure ratio of 17.7 relative to ambient conditions and a high pressure turbine inlet temperature of 1220 °C. Even if the thermal efficiency associated to the pressure ratio of 17.7 is 1% lower than the maximum thermal efficiency, the irreversibilities related to this pressure ratio decrease approximately 1 GW with respect to irreversibilities of the optimal pressure ratio for the thermal efficiency. In addition, this paper contributes to develop a mathematical model to estimate the high turbine inlet temperature as well as the pressure ratio of the low and high pressure turbines

(+)-Ascosalitoxin and Vermelhotin, a Calmodulin Inhibitor, from an Endophytic Fungus Isolated from <i>Hintonia latiflora</i>

Chemical investigation of the endophytic MEXU 26343, isolated from the medicinal plant <i>Hintonia latiflora</i>, yielded the known polyketide vermelhotin (<b>1</b>) and a new salicylic aldehyde derivative, namely, 9<i>S</i>,11<i>R</i>-(+)-ascosalitoxin (<b>2</b>). The structure and absolute configuration of the new compound were established through extensive NMR spectroscopy and molecular modeling calculations at the DFT B3LYP/DGDZVP level, which included the comparison between theoretical and experimental optical rotation values. In addition, chemical transformations of <b>2</b> yielded suitable derivatives for NOESY and ¹H–¹H NMR coupling constant analyses, which reinforce the stereochemical assignment. The potential affinity of <b>1</b> and <b>2</b> with (Ca²⁺)₄-<i>h</i>CaM in solution was measured using the fluorescent biosensor <i>h</i>CaM M124C-<i>mBBr</i>. The results showed that <b>1</b> bound to the protein with a dissociation constant (<i>K</i>_d) of 0.25 ± 0.04 μM, close to that of chlorpromazine (<i>K</i>_d = 0.64 ± 0.03 μM), a classical CaM inhibitor. The stoichiometry ratio of <b>1</b> to (Ca²⁺)₄-<i>h</i>CaM was 1:4, similar to other well-known CaM ligands

<i>Echinacea purpurea</i> plants grown from sterilized seeds.

<p><i>E</i>. <i>purpurea</i> seeds were sterilized following removal of the epidermis and grown under sterile conditions for six weeks. The negative control was prepared using the same reaction vessels and solvents as for the individual plants, but without plant material. The seed used to grow plant 49 was subjected to surface sterilization but with epidermis intact (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124276#pone.0124276.s002" target="_blank">S1 Table</a>). Plants were harvested and extracts tested for LPS content (A) and ability to induce production of TNF-α from RAW 264.7 cells after 16–18 h incubation (B). Data show the means ± SD of duplicate experiments measuring TNF-α secretion in panel A, and the mean ± SEM of triplicate measurements of LPS content in panel B. Statistical analysis was performed using the Student’s T test, ***p < 0.001.</p

Structure and activity of xanthienopyran.

<p>The structure of xanthienopyran was elucidated by comparison of NMR and MS data with published values (A). The influence of xanthienopyran on TNF-α secretion by RAW 264.7 macrophage-like cells alone (B) or in the presence of 10 ng/mL of LPS (C) was evaluated. The influence of dodeca-2E,4E-dienoic acid isobutylamide (<b>15</b>) on TNF-α secretion by RAW 264.7 macrophage-like cells in the presence of 10 ng/mL of LPS (C) was evaluated as comparison. Treatments were for 16–18 hr. and levels of TNF-α in supernatants were quantified by ELISA. Data shown are means +/- SEM from three independent experiments. Statistical analysis was performed using the Student’s T test, *p<0.05.</p

Alkylamide content of an <i>Echinacea purpurea</i> extract, chloroform layer, and column fractions from the chloroform layer.

<p>a. Concentration is reported for one of the major alkylamides in the extract, alkylamide 5 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124276#pone.0124276.g003" target="_blank">Fig 3</a> (dodeca-2E,4Z-diene-8,10-diynoic acid isobutylamide). The total alkylamide concentration was estimated using the calibration curve for this compound. Reported concentrations are means+/- SD from triplicate measurements by LC-MS as described in the Materials and Methods.</p><p>b. Below LOQ (limit of quantification) indicates that alkyamides were detected but were present at concentrations below the limit of quantitation for the method.</p><p>c. ND indicates that alkylamides were not detected, i.e. not present at levels above the limit of detection (LOD).</p><p>Alkylamide content of an <i>Echinacea purpurea</i> extract, chloroform layer, and column fractions from the chloroform layer.</p

The effects of <i>Echinacea purpurea</i> extract fractions on production of TNF-α.

<p>Fractions from the flash chromatography separation of the <i>E</i>. <i>purpurea</i> extract chloroform layer (CL) were tested for their effects on the production of TNF-α from RAW 264.7 cells in the absence (A) or presence (B) of 10 ng/mL LPS. Treatments were for 16–18 h and levels of TNF-α in supernatants were quantified by ELISA. Each fraction was tested at 50 and 100 μg/mL. All data shown are means +/- SEM from three independent experiments. Statistical analysis was performed using the Student’s T test, *p<0.05, **p<0.01. M, media; L, LPS; CL, chloroform layer.</p

Influence of 75% ethanol extract and liquid:liquid partitions from <i>Echinacea purpurea</i> extract on TNF-α production by RAW 264.7 cells.

<p>Extract and partitions were tested at concentrations of 50 μg/mL (A and C) and 100 μg/mL (B and D) expressed as mass of extract per assay well volume. Cells were unstimulated in A and B and stimulated with 100 ng/mL LPS in C and D. Supernatants were harvested after 16–18 hr. and levels of TNF-α measured by ELISA. M, media; L, LPS; EE, ethanol extract; HL, hexane layer, ML, methane layer; WL, water layer; CL, chloroform layer. Values shown are means +/- SD from a single representative experiment. Statistical analysis was performed using the Student’s T test, *p<0.05, **p<0.01, ***p<0.001.</p

<i>Echinacea purpurea</i> fraction effects on CCL3 and CCL5.

<p>Fractions from the silica gel column were tested for their effects on the production of CCL3 (MIP1-α) and CCL5 (RANTES) from RAW 264.7 cells in the absence (A and B) or presence (C and D) of 10 ng/mL LPS. Treatments were for 16–18 hr. and chemokine levels in supernatants were quantified by ELISA. Each fraction was tested at 50 μg/mL. Data shown are means +/- SEM or SD from three (CCL3) and two (RANTES) independent experiments. Statistical analysis was performed using the Student’s T test, *p<0.05. M, media; CL, chloroform layer.</p