Thermohydrodynamic Behavior of Misaligned Plain Journal Bearings: Theoretical and Experimental Approaches

Hydrodynamic journal bearings are essential components for supporting and guiding the rotating shafts of high-speed machinery. Manufacturing defects in assembly or thermal distortions may introduce problems during running, such as misalignment. The destructive effects of this kind of running problem have justified the development of a numerical model to predict the bearing operating characteristics under steady-state conditions. The present work presents in detail the three-dimensional thermohydrodynamic approach adopted in this study in order to consider the thermal field variations. This model also includes lubricant film rupture and reformation phenomena by conserving the mass flow rate. In addition, an experimental validation is made by comparison with measurements carried out on our test device for various operating conditions and misalignment torques. The influence of misalignment direction is also investigated by considering numerical and experimental approaches used in the study of bearing behavior variations.     

Meiotic behavior and pollinic viability in bean cultivars

The aims of this study were to determine the meiotic behavior and to estimate pollen grains viability in bean (Phaseolus vulgaris L.) cultivars. Flower buds were collected during different developmental stages of the Mesoamerican bean cultivars IAPAR 44, Guapo Brilhante, BRS Expedito, BRS Valente, Guateian 6662 and Pérola, and the Andean bean cultivar Iraí, grown in a greenhouse. The meiotic index was determined by anther squashing of material fixed in absolute ethanol-glacial acetic acid (3:1) and stained with acetic orcein. No meiotic abnormalities were observed and the meiotic indices were high for all cultivars, indicating that the mismatch generated during crosses is not related to any meiotic changes. Estimation of pollen viability was made by comparing acetic orcein staining vs. Alexander’s reactive: pollen viability was high in all cultivars with either stain, but was significantly higher when using the acetic orcein stain (>99%). Though some cultivar showed a significantly smaller pollen size, the range of variation among cultivars was low (means’ range 51-66 μm)     

Internet Predictions

More than a dozen leading experts give their opinions on where the Internet is headed and where it will be in the next decade in terms of technology, policy, and applications. They cover topics ranging from the Internet of Things to climate change to the digital storage of the future.     

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.     

An Adaptable Job Submission System Based on Moderate Price-Adjusting Policy in Market-Based Grids

A market-based computational grid is made up of large sets of heterogeneous and geographically distributed resources that are gathered into virtual organizations for executing consumer’s applications. One of the most important challenges in market-based grid systems is the management of grid users, which is called resource providers and consumers. The existing methods provide some alternative mechanisms for this problem, but they are not fully adequate. To address this problem, we propose an enhanced approach for adjusting price of grid resource using new effective parameters of microeconomic issue and also for prioritizing current jobs in the queue. This proposed approach is integrated with a cooperative method among local schedulers to accept jobs based on auction model. The results conclude that the inclusion of new parameters in price-adjusting affects the payment budget and job submission behavior of the schedulers. The evaluations of experimental results prove a remarkable performance of the proposed approach in diverse conditions and job workloads.     

Milk with different somatic cells counts and the physicochemical,microbiological characteristics and fatty acid profile of pasteurised milk cream: is there an association?

In this study, raw cow milk containing somatic cells counts (SCC) at mean levels of 39 000 cells mL^?1 (low), 349 000 cells mL^?1 (intermediate) and 1 297 000 cells mL^?1 (high) was used for the production of pasteurised cream. Physicochemical (pH, fat and fatty acid profile) and microbiological analyses (mesophilic and psychrotrophs) were performed in the obtained creams during 30 days of refrigerated storage at 5 °C ± 2. No interactions (P > 0.05) were found between SCC, storage time and the physicochemical and microbiological variables studied. Fatty acid profile was similar among the SCC creams, except for oleic acid (C18:1), which decreased (P < 0.05) in intermediate and high SCC creams. Considering the technological aspect, our findings suggest that milk cream manufacture can be an interesting option for the use of high SCC milk.     

Distribution of fungi and aflatoxins in a stored peanut variety

The objective of the present study was to evaluate the mycoflora and occurrence of aflatoxins in stored peanut samples (hulls and kernels) from Tupã, State of São Paulo, Brazil. The samples were analyzed monthly over a period of one year. The results showed a predominance of Fusarium spp. (67.7% in hulls and 25.8% in kernels) and Aspergillus spp. (10.3% in hulls and 21.8% in kernels), and the presence of five other genera. The growth of Aspergillus flavus was mainly influenced by temperature and relative humidity. Analysis of hulls showed that 6.7% of the samples were contaminated with AFB₁ (mean levels = 15–23.9 μg/kg) and AFB₂ (mean levels = 3.3–5.6 μg/kg); in kernels, 33.3% of the samples were contaminated with AFB₁ (mean levels = 7.0–116 μg/kg) and 28.3% were contaminated with AFB₂ (mean levels = 3.3–45.5 μg/kg). Analysis of the toxigenic potential revealed that 93.8% of the A. flavus strains isolated were producers of AFB₁ and AFB₂.     

A chemometric study of phosphodiesterase 5 inhibitors

This work presents a chemometric classification for a set of phosphodiesterase 5 inhibitors, based on a pattern recognition method widely used in quantitative structure-activity (QSAR) studies, hierarchical cluster analysis (HCA) and principal component analysis (PCA), aiming to access the most relevant structural and physicochemical variables related to phosphodiesterase 5 inhibition and to quantify the similarity of the structures within the set of inhibitors. Our model is capable of classifying a test set of 26 known phosphodiesterase 5 inhibitors in terms of similarity, the results being consistent with published experimental data.     

Microclimatic coupling as a solution to improve building energy simulation in an urban context

To streamline the design of the energy efficient buildings, appropriate tools are needed to assess their energy performance taking into account the microclimatic context.Numerical simulation seems to be the most suitable issue, but none tool is dedicate to the direct evaluation of the microclimate influence on the building energy consumption. A complete solution could be to use both CFD and thermoradiative simulation tools complementary with the coupling technique perspective. This paper presents both a developed CFD-thermoradiative coupled simulation tool and a typical application on an urban fragment.The results lead to two kind of observations:

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Integration of the thermal model of a building in the microclimatic simulation platform enable a quantitative evaluation of the building energy demand regarding different urban design scenarii (e.g. mineralized vs vegetated).

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Different physical phenomena do not contribute as much in the energy balance and it is important to compute precisely each one to obtain the small scale microclimatic influence.

     

Detection and resolution of normative conflicts in multi-agent systems: a literature survey

Multi-agents systems are composed of autonomous and possibly heterogeneous software agents that act according to their own interests. Some coordination mechanism must be adopted to ensure a proper functioning of the whole system. Norms can be viewed as a powerful means to regulate and influence the behaviour of the agents by specifying, for instance, obligations, permissions, or prohibitions in a given context. A critical issue that must be considered in a system governed by multiple norms is the possible existence of normative conflicts. A conflict between norms is a situation in which the fulfilment of a norm causes a violation of another one. In this paper, we present several techniques that have been proposed to detect and resolve normative conflicts in multi-agent systems. Our aim is to organize the literature, present a classification of the techniques found, and provide a means to compare alternative approaches dealing with normative conflicts.