Heat flow in the postquasistatic approximation

We apply the postquasistatic approximation to study the evolution of spherically symmetric fluid distributions undergoing dissipation in the form of radial heat flow. For a model which corresponds to an incompressible fluid departing from the static equilibrium, it is not possible to go far from the initial state after the emission of a small amount of energy. Initially collapsing distributions of matter are not permitted. Emission of energy can be considered as a mechanism to avoid the collapse. If the distribution collapses initially and emits one hundredth of the initial mass only the outermost layers evolve. For a model which corresponds to a highly compressed Fermi gas, only the outermost shell can evolve with a shorter hydrodynamic time scale.Comment: 5 pages, 5 figure

Extraction of silymarin compounds from milk thistle (Silybum marianum) seed using hot, liquid water as the solvent

High-value specialty chemicals are usually obtained from natural products by extracting with generally regarded as safe (GRAS) solvents. Because organic solvents are quite often used, high operating and disposal costs occur. When compared to traditional solvents, water is an interesting alternative because of its low operating and disposal costs. Milk thistle contains compounds (taxifolin, silychristin, silydianin, silybinin A, and silybinin B) that display hepatoxic protection properties. This paper examines the batch extraction of silymarin compounds from milk thistle seed meal in 50°C, 70°C, 85°C and 100°C water as a function of time. For taxifolin, silychristin, silybinin A, and silybinin B, extraction with 100°C water resulted in the highest yields. After 210 min of extraction at 100°C, the yield of taxifolin was 1.2 mg/g of seed while the yields of silychristin, silybinin A, and silybinin B were 5.0, 1.8 and 3.3 mg/g of seed, respectively. The ratios of the extracted compounds, and particularly the ratios at long extraction times, showed that the more polar compounds (taxifolin and silychristin) were preferentially extracted at 85°C, while the less polar silybinin was preferentially extracted at 100°C

Estimated glomerular filtration rate is a poor predictor of the concentration of middle molecular weight uremic solutes in chronic kidney disease

Background: Uremic solute concentration increases as Glomerular Filtration Rate (GFR) declines. Weak associations were demonstrated between estimated GFR (eGFR) and the concentrations of several small water-soluble and protein-bound uremic solutes (MW500Da). Materials and Methods: In 95 CKD-patients (CKD-stage 2-5 not on dialysis), associations between different eGFR-formulae (creatinine, CystatinC-based or both) and the natural logarithm of the concentration of several LMWP's were analyzed: i.e. parathyroid hormone (PTH), Cystatin C (CystC), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), leptin, retinol binding protein (RbP), immunoglobin light chains kappa and lambda (Ig-kappa and Ig-lambda), beta-2-microglobulin (beta M-2), myoglobin and fibroblast growth factor-23 (FGF-23)). Results: The regression coefficients (R-2) between eGFR, based on the CKD-EPI-Crea-CystC-formula as reference, and the examined LMWP's could be divided into three groups. Most of the LMWP's associated weakly (R-2 0.7). Almost identical R-2-values were found per LMWP for all eGFR-formulae, with exception of CystC and beta M-2 which showed weaker associations with creatinine-based than with CystC-based eGFR. Conclusion: The association between eGFR and the concentration of several LMWP's is inconsistent, with in general low R-2-values. Thus, the use of eGFR to evaluate kidney function does not reflect the concentration of several LMWP's with proven toxic impact in CKD

Dynamic response assessment of an offshore wind turbine under Peruvian environmental conditions

This paper presents a dynamic response analysis of an offshore monopile wind turbine to be deployed at a near-shore area in the south-centre part of the Peruvian coast (Marcona). It is a 5 MW three bladed wind turbine that operates in an aggressive offshore environment described by its stochastic behaviour. Thus it is necessary to use a statistical approach for its characterization. The operating wind turbine is simulated using an aero-hydro-servo-elastic computational tool (FAST) that allows the simulation of coupled systems. After the simulation, this work analyses relevant dynamic responses (thrust, torque, shear forces, and bending moments). Time series of these responses at critical zones of the wind turbine are presented. The results indicate high variability of the responses and critical fluctuations located at the mudline. It is found that this variability is due to the additional dynamic loads coming from the ocean waves. This is a big issue to consider when designing a monopile offshore wind turbine operating under the Peruvian environmental conditions

Quality-in-use app evaluation: case of a recruitment app for Portuguese SMEs

E-Recruitment, a term that refers to online recruitment, has been increasingly adopted by companies that are prone to changes and ready to the constant evolution of society. Thus, this study aims to evaluate the impact of a recruitment application in Portugal. This application was developed to meet the needs of candidates and employers, and its evaluation is made in terms of quality-in-use by both parties, small and medium-sized companies in Portugal and potential job offers applicants. To achieve the results related to the defined objective, managers from six companies were interviewed, producing a qualitative evaluation of the application, accompanied by a survey to achieve its quantitative evaluation (3.36 in 4 points). Simultaneously, a quantitative study was carried out among the candidates for evaluation of the mobile application, 3.67 points out of 4 possible. Thus, it was verified that the application developed is suitable for candidates. However, despite the positive evaluation, recruiters point to improvements in the company module.info:eu-repo/semantics/publishedVersio

Equation of state and transport processes in self--similar spheres

We study the effect of transport processes (diffusion and free--streaming) on a collapsing spherically symmetric distribution of matter in a self--similar space--time. A very simple solution shows interesting features when it is matched with the Vaidya exterior solution. In the mixed case (diffusion and free--streaming), we find a barotropic equation of state in the stationary regime. In the diffusion approximation the gravitational potential at the surface is always constant; if we perturb the stationary state, the system is very stable, recovering the barotropic equation of state as time progresses. In the free--streaming case the self--similar evolution is stationary but with a non--barotropic equation of state.Comment: 9 pages, 2 figure

Decision boundaries using Bayes factors: the case of cloud masks

We assess the use of an approximation to the Bayes factor for objectively assessing spatial segmentation models. The Bayes factor allows us to automatically determine thresholds, in multidimensional feature space, for such objectives as cloud mask definition. We compare our results with a cloud map currently provided as a data product

Determination of the optimal range of the compressor inlet air temperature in a power plant with stig cycle through of advanced exergetic analysis

Conventional exergy analysis identifies the more inefficient components; however, this doesn’t regard interaction between components, neither real improvement potential to each component of the system, this information is providing for the advanced exergy analysis. In this paper was developed an advanced exergy analysis to determine the optimal range of the compressor inlet air temperature, to compensate the power loss in a power plant with Stig cycle and an air cooling system. This plant without cooling system at ISO conditions produce 52 MW, while in local conditions (32 °C, 80%RH) its productions decreases to 44.3MW. The results showed that for every degree centigrade that the air temperature decreases at inlet compressor the power output increases in 0.17 MW and total destroyed exergy increases 0.23 MW. It was determined that for the optimal range of compressor inlet air temperature is between 10 and 12°C; at this range were obtained the highest power output values, and the values of the avoidable and endogenous exergy destroyed are diminished in 0.28 MW and 0.20 MW respectively compared to those given in local operating conditions. Copyright © 2019 ASME

Stigma-based rejection experiences affect trust in others

This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.Rejection experiences are likely to influence individuals’ subsequent feelings about others and their behaviour in social interactions. The present study specifically examined whether stigma-based rejection leads to decreased trust in others, compared to rejections that are not stigma-based. Trust was assessed behaviourally with an online task where the interaction partner was pre-programmed. Participants showed less trust after stigma-based rejection than after a non-stigma based rejection. This research provides the first experimental evidence that stigma-based rejection uniquely influences trust in others