Structural and thermophysical properties characterization of continuously reinforced cast Al matrix composite

In this work the process of manufacturing a continuously reinforced cast Al matrix composite and its properties are presented.The described technology permits obtaining a structural material of competitive properties compared to either heat treatable aluminum alloys or polymer composites for several types of applications.The examined thermophysical properties and structural characterization,including material anisotropy,coupled with the results of previous measurements of the mechanical properties of both Al2O3reinforcing filaments and metallic prepregs have proven the high quality of this material and the possibility of its operation under special loading modes and environmental conditions.Microscopic examinations(LM,SEM)were carried out to reveal the range of morphological homogeneity of the microstructure,the anisotropy of the filament band distribution,and simultaneously the adhesive behavior of the metal/fiber interface.The 3D morphology of the chosen microstructure components was revealed by computed tomography.The obtained results indicate that special properties of the examined prepreg materials have been strongly influenced,on the one hand,by the geometry of its internal microstructure,i.e.spatial distribution and volume fraction of the Al2O3 reinforcing filaments and,on the other hand,by a very good compatibility obtained between the individual metal prepreg components.     

Scheduling to Minimize Staleness and Stretch in Real-Time Data Warehouses

We study scheduling algorithms for loading data feeds into real time data warehouses, which are used in applications such as IP network monitoring, online financial trading, and credit card fraud detection. In these applications, the warehouse collects a large number of streaming data feeds that are generated by external sources and arrive asynchronously. Data for each table in the warehouse are generated at a constant rate, different tables possibly at different rates. For each data feed, the arrival of new data triggers an update that seeks to append the new data to the corresponding table; if multiple updates are pending for the same table, they are batched together before being loaded. At time τ, if a table has been updated with information up to time r≤τ, its staleness is defined as τ−r.     

Subterranean Herbivore-induced Volatiles Released by Citrus Roots upon Feeding by <Emphasis Type="Italic">Diaprepes abbreviatus</Emphasis> Recruit Entomopathogenic Nematodes

Herbivore-induced volatile emissions benefit plant hosts by recruiting natural enemies of herbivorous insects. Such tritrophic interactions have been examined thoroughly in the above-ground terrestrial environment. Recently, similar signals have also been described in the subterranean environment, which may be of equal importance for indirect plant defense. The larvae of the root weevil, Diaprepes abbreviates, are a serious pest of citrus. Infestations can be controlled by the use of entomopathogenic nematodes, yet the interactions between the plant, insect and nematode are poorly understood and remain unpredictable. In bioassays that used a root zone six-arm olfactometer, citrus roots (‘Swingle citrumelo’ rootstock) recruited significantly more entomopathogenic nematodes (Steinernema diaprepesi) when infested with root weevil larvae than non-infested roots. Infested plants were more attractive to nematodes than larvae alone. Roots damaged by weevil larvae attracted more nematodes than mechanically damaged roots and sand controls. By dynamic in situ collection and GC-MS analysis of volatiles from soil, we determined that four major terpene compounds were produced by infested plant roots that were not found in samples from non-infested roots or soil that contained only larvae. Solvent extracts of weevil-infested roots attracted more nematodes than extracts of non-infested roots in a two choice sand-column bioassay. These findings suggest that Swingle citrus roots release induced volatiles as an indirect defense in response to herbivore feeding, and that some of these induced volatiles function as attractants for entomopathogenic nematodes.     

Monitoring respiration and cardiac activity using fiber Bragg grating-based sensor

This paper shows the design of a fiber-based sensor for living activities in human body and the results of a laboratory evaluation carried out on it. The authors have developed a device that allows for monitoring the vibrations of human body evoked by living activities--breathing and cardiac rhythm. The device consists of a Bragg grating inscribed into a single mode optical fiber and operating on a wavelength of around 1550?nm. The fiber Bragg grating (FBG) is mounted inside a pneumatic cushion to be placed between the backrest of the seat and the back of the monitored person. Deformations of the cushion, involving deformations of the FBG, are proportional to the vibrations of the body leaning on the cushion. Laboratory studies have shown that the sensor allows for obtaining dynamic strains on the sensing FBG in the range of 50-124 μ strain caused by breathing and approximately 8.3 μstrain induced by heartbeat, which are fully measurable by today's FBG interrogation systems. The maximum relative measurement error of the presented sensor is 12%. The sensor's simple design enables it to be easily implemented in pilot's and driver's seats for monitoring the physiological condition of pilots and drivers.     

Identification of Cyclopropaneoctanoic Acid 2-Hexyl in Human Adipose Tissue and Serum

Fatty acids containing a cyclopropane ring in their structure (cyclopropane FA) have been found in a wide variety of bacteria, a number of protozoa, and Myriapoda. Little is known about cyclopropane FA in mammal, especially in human tissues. The present study deals with the identification of cyclopropane FA in adipose tissue and serum of humans and rats. Fatty acids extracted from the adipose tissue and serum obtained from obese women during bariatric surgery were methylated and analyzed on GC–MS. We have identified: cyclopropaneoctanoic acid 2-hexyl, cyclopropaneoctanoic acid 2-octyl, cyclopropanenonanoic acid, and 2-[[2-[(2-ethylcyclopropyl)methyl]cyclopropyl]methyl] acid in human adipose tissue. We confirmed the presence of cyclopropaneoctanoic acid 2-hexyl by derivatization of FA extracted from human adipose tissue to picolinyl esters. Cyclopropaneoctanoic acid 2-hexyl was the main cyclopropane FA (approximately 0.4 % of total fatty acids in human adipose tissue, and about 0.2 % of total fatty acids in the serum). In adipose tissue cyclopropaneoctanoic acid 2-hexyl was found mainly in triacylglycerols, whereas in serum in phospholipids and triacylglycerols. The cyclopropaneoctanoic acid 2-hexyl has also been found in serum, and adipose tissue of rats in amounts comparable to humans. The content of cyclopropaneoctanoic acid 2-hexyl decreased in adipose tissue of rats maintained on a restricted diet for 1 month. In conclusion, we demonstrated that cyclopropaneoctanoic acid 2-hexyl is present in human adipose tissue and serum. Adipose tissue cyclopropaneoctanoic acid 2-hexyl is stored mainly in triacylglycerols and the storage of this cyclopropane FA is affected by food restriction.     

Sending Mixed Messages: A Trophic Cascade Produced by a Belowground Herbivore-Induced Cue

Plants defend themselves against herbivores both directly (chemical toxins and physical barriers) and indirectly (attracting natural enemies of their herbivores). Previous work has shown that plant roots of citrus defend against root herbivores by releasing an herbivore-induced plant volatile (HIPV), pregeijerene (1,5-dimethylcyclodeca-1,5,7-triene), that attracts naturally occurring entomopathogenic nematodes (EPNs) to Diaprepes abbreviatus larvae when applied in the field. However, the soil community is complex and contains a diversity of interspecific relationships that modulate food web assemblages. Herein, we tested the hypothesis that other nematode types beyond EPNs, as well as, nematophagous fungi are affected by the same HIPV that attracts EPNs to herbivore-damaged roots. We employed molecular probes designed to detect and quantify nematodes from the Acrobeloides–group (free-living bacterivorous nematodes, FLBNs), some of which compete with EPNs by ‘hyperparasitizing’ insect cadavers, and five species of nematophagous fungi (NF), which attack and kill EPNs. In two different agricultural systems (citrus and blueberry), we detected diverse species of nematodes and fungi; however, only the behavior of FLBNs was affected in a manner similar to that reported previously for EPNs. Although detected, NF abundance was not statistically affected by the presence of the belowground HIPV. We provide the first evidence showing subterranean HIPVs behave much the same as those aboveground, attracting not only parasitoids, but also hyperparasites and other food web members.     

Biotemplated nanopatterning of planar surfaces with molecular motors

We report on the generation of nanometer-wide, non-topographical patterns of proteins on planar surfaces. In particular, we used the regular lattice of reconstituted microtubules as template structures to specifically bind and transfer kinesin-1 and nonclaret disjunctional motor proteins. The generated tracks, which comprise dense and structurally oriented arrays of functional motor proteins, proved to be highly efficient for the guiding of microtubule transporters.     

Identification of Rheological Parameters on the Basis of Various Types of Compression and Tension Tests

The objective of the project was to determine flow stress on the basis of various plastometric tests. The experiments used uniaxial compression, ring compression, and plane strain compression for two sizes of samples and tensile tests. The material was carbon‐manganese steel, and all the tests were performed at three temperatures (900, 1000, and 1100°C) and at three strain rates for each temperature (0.1, 1, and 10 s^?1). Inverse analysis was applied to the interpretation of the results of all compression tests. The flow stresses obtained from various compression tests were compared resulting in the following observations: consistent results between the tests were observed for low values of the Zener‐Hollomon parameter, but some discrepancies appeared for larger values of this parameter. The sensitivity of the results of inverse analysis with respect to the friction factor was investigated next, and it was concluded that the flow stress determined from ring compression showed the largest sensitivity to friction. This sensitivity was lower for uniaxial compression and plane strain compression of small samples, and no sensitivity was observed for plane strain compression of large samples. Finally, the simulations of the tensile tests were performed using the rheological models determined in compression, and reasonably good results were obtained.     

Corrosion current density prediction in reinforced concrete by imperialist competitive algorithm

This study attempted to predict corrosion current density in concrete using artificial neural networks (ANN) combined with imperialist competitive algorithm (ICA) used to optimize weights of ANN. For that reason, temperature, AC resistivity over the steel bar, AC resistivity remote from the steel bar, and the DC resistivity over the steel bar are considered as input parameters and corrosion current density as output parameter. The ICA–ANN model has been compared with the genetic algorithm to evaluate its accuracy in three phases of training, testing, and prediction. The results showed that the ICA–ANN model enjoys more ability, flexibility, and accuracy.     

Sampling from repairs of conditional functional dependency violations

Violations of functional dependencies (FDs) and conditional functional dependencies (CFDs) are common in practice, often indicating deviations from the intended data semantics. These violations arise in many contexts such as data integration and Web data extraction. Resolving these violations is challenging for a variety of reasons, one of them being the exponential number of possible repairs. Most of the previous work has tackled this problem by producing a single repair that is nearly optimal with respect to some metric. In this paper, we propose a novel data cleaning approach that is not limited to finding a single repair, namely sampling from the space of possible repairs. We give several motivating scenarios where sampling from the space of CFD repairs is desirable, we propose a new class of useful repairs, and we present an algorithm that randomly samples from this space in an efficient way. We also show how to restrict the space of repairs based on constraints that reflect the accuracy of different parts of the database. We experimentally evaluate our algorithms against previous approaches to show the utility and efficiency of our approach.