Compact Degree Research Articles

Fault-tolerant rate-monotonic compact-factor-driven scheduling in hard-real-time systems

Considering the disadvantage of first-fit strategy in fault-tolerant rate-monotonic first-fit (FTRMFF) algorithm, we analyze the slack time of processors and the schedulability of periodic tasks in rate-monotonic (RM) algorithm. Then, the RM-based idleness factor and compact factor are presented to quantify the compact degree of tasks assigned to the same processor. In this paper, the novel fault-tolerant rate-monotonic compact-factor-driven (FTRMCFD) algorithm, which follows the principle of compact factor maximal when allocating the processors for tasks, is proposed. FTRMCFD algorithm makes every processor contain more tasks and get higher utilization to increase the schedulability performance of distributed systems. The simulation experiments reveal that FTRMCFD can reduce the number of required processors by up to 11.5% (with an average of 5.3%).

Influence of the total gas flow rate on high rate growth microcrystalline silicon films and solar cells

This paper reports that high-rate-deposition of microcrystalline silicon solar cells was performed by very-high-frequency plasma-enhanced chemical vapor deposition. These solar cells, whose intrinsic μc-Si:H layers were prepared by using a different total gas flow rate (Ftotal), behave much differently in performance, although their intrinsic layers have similar crystalline volume fraction, opto-electronic properties and a deposition rate of ∼ 1.0 nm/s. The influence of Ftotal on the micro-structural properties was analyzed by Raman and Fourier transformed infrared measurements. The results showed that the vertical uniformity and the compact degree of μc-Si:H thin films were improved with increasing Ftotal. The variation of the microstructure was regarded as the main reason for the difference of the J−V parameters. Combined with optical emission spectroscopy, we found that the gas temperature plays an important role in determining the microstructure of thin films. With Ftotal of 300 sccm, a conversion efficiency of 8.11% has been obtained for the intrinsic layer deposited at 8.5 Å/s (1 Å = 0.1 nm).

Disassembly Sequence Planning Based on Generalized Axis Theory

How to obtain the compact and reasonable expression of all feasible disassembly paths has become the most important problem to be resolved in disassembly sequence planning. In order to optimize the sub-assembly clustering in planning of disassembly path, and to avoid combination explosion problem of calculation caused by traditional method,a theory of generalized axis conformed with the engineering semantic information and the concept about disassembly priority adjustment coefficient are put forward, considering the information about assembly structure and assembly process, quoting and extending the concept of matching relation which express the compact degree between parts. On operation procedure, it’s first to gain the coaxial membership matrix and its modified matrix by using the expression form of adjacency matrix, the coaxiality coefficient function and the disassembly priority distributing table. Then, it can be obtained considering related algorithms of fuzzy cluster analysis of transitivity fuzzy equivalent matrix and λ dynamic product clustering relationship graph. Using these, the sub-assembly clustering can be obtained in the end. The benefit of the proposed theory and method is illustrated through an example, which can improve the consistence with the actual engineering situation, and calculating work can be greatly reduced.

Fuzzy compact operators and topological degree theory

In this paper we first prove that the definition of fuzzy norm continuity and fuzzy boundedness of linear operators are equivalent. We show that the continuity assumption in the definition of compact linear operator is not necessary. We also point out that there is a gap in the proof of a theorem of Xiao and Zhu and we give a corrected version of the theorem such that all results based on the revised theorem remain true. Furthermore, we define a fuzzy product norm on the Cartesian product of two fuzzy normed spaces and prove a multiplicative property for the Leray–Schauder topological degree.

Microstructure and oxidation protective ability of MoSi2-SiC-Si coating toughened with SiC whiskers for carbon/carbon composites

To prevent carbon/carbon (C/C) composites from oxidation at high temperatures, a SiC whisker (SiCw) toughened MoSi2–SiC–Si coating was prepared on the C/C surface by a two step technique of slurry and pack cementation. Scanning electron microscopy (SEM) analysis shows that, with the content of SiCw increasing, the dimensions and frequency of cracks in the coating decrease obviously. At the same time, the thickness and compact degree of the coating reduce with the increase of the SiCw content. Oxidation tests show that, as the content of SiCw is 10 wt-%, the coating possesses a better anti-oxidation property, and the weight loss of the coated sample is only 0˙8% after oxidation at 1773 K for 200 h. The weight loss of the as-coated C/C composites is primarily due to the reaction of the C/C matrix and oxygen diffusing through the penetration cracks and holes in the coating.

Effect of heat treatment on the performance of TiO 2-Pt/CNT catalysts for methanol electro-oxidation

TiO 2-Pt/CNT catalysts before and after heat treatment were prepared. Their catalytic activities for methanol and CO electro-oxidation were studied in detail. The results showed that the proper amount of hydrous TiO 2 in TiO 2-Pt/CNTs (e.g. heated at 200 °C for 2 h) was favorable for enhancing the catalytic activity of Pt/CNTs, which provided evidence for bi-functional mechanism. The studies on the catalysts with different TiO 2/Pt molar ratio displayed that the optimum molar ratio varied with the increase of heat treatment temperature. It was found that the optimum molar ratio of TiO 2/Pt was at 1:2 for the catalysts without heat treatment and was at 1:1 for the catalysts by heat treatment at 500 °C. This fact was ascribed to the difference in compact degree between TiO 2 and Pt/CNTs before and after heat treatment. Considering the influence of heating temperature, it was found that TiO 2-Pt/CNT catalyst heated at 200 °C for 2 h had better catalytic activity for methanol oxidation.

Effect of sulphate-reducing bacteria on the electrochemical impedance spectroscopy characteristics of 1Cr18Ni9Ti

The electrochemical characteristics of 1Cr18Ni9Ti in sulphate-reducing bacteria (SRB) solutions and the biofilm of SRB on the surface of the 1Cr18Ni9Ti electrode were studied by electrochemical, microbiological, and surface analysis methods. Electrochemical impedance spectroscopy (EIS) of 1Cr18Ni9Ti was measured in the solutions with and without SRB at the culture time of 2, 4, 8 d, respectively. The measurement used two test methods, the nonimmersion electrode method and the immersion electrode method. It was found that the polarization resistance ( R p) of 1Cr18Ni9Ti in the solutions without SRB is the greatest for each test method. When using the nonimmersion electrode method, R p shifts negatively at first and then positively, and the time constant is only one. Although using the immersion electrode method, the R p shifts positively at first and then negatively, and the time constant also changes when the biofilm forms. The biofilm observed through SEM is with pores. It was demonstrated that SRB has accelerated corrosion action on 1Cr18Ni9Ti. The protection effect of the biofilm on the electrode depends on the compact degree of the film.

Compaction Quality of Bitumen Mixtures Based on Ultrasonic Methods

Water damage of asphalt concrete pavements has been one of the major distresses in highway engineering. Engineering experiences and research results indicate that this damage is due to the extortionate air voids of bitumen mixtures. Paranormal porosity of asphalt mixture is largely the result of the poor controlling of compact degree during paving process. The quality of asphalt pavement is subjected to the controlling methods of compacting of bitumen mixtures. Ultrasonic is an excellent method for non-destructive testing used in various engineering fields. It is also a potentially effective tool to be applied in the control and evaluation of the compaction quality of bitumen mixtures. This paper presents the results of a study aimed at the applicability of ultrasonic technology for evaluation of porosity and compaction quality of bitumen mixtures. It is shown that this technology, which has been successfully used for many years for evaluation of Portland concrete structures, might be used in asphalt pavement engineering to provide a simple, quick, and objective methodology for control and evaluation of the compact quality of bitumen mixtures. The results of laboratory testing demonstrate the potential of this technology.

Improving Thermal Stability of BaMgAl 10O 17:Eu Phosphor

Heterogeneous precipitation method was used to prepared surface coating on self-made BaMgAl 10O 17:Eu phosphor. Results illustrate that the coating film can be silicon dioxide in amorphous state with 50 nm in thickness. Photoluminescence results indicate that the coating layer presents an observable improved effect on the enhancement of thermal stability. When baked at 600 °C for 1 h, the luminance of coated BAM keeps at 92% higher than that of uncoated BAM by 23%. This protective effect can be attributed to the high compact degree and uniformity of this amorphous SiO 2 coating film which is served as a diffusion block layer to inbreak oxygen atom, thus releases the oxidation extent of Eu 2+ effectively.

Electrical conductivity of sintered powder compacts

Some equations for calculating the electrical conductivity of porous materials are reviewed and their applicability to sintered powder compacts is discussed. A previous equation proposed by the authors, in which the effective conductivity of a sintered compact is composed of a function of the fully dense material conductivity, the compact porosity degree and tap porosity of the starting powder, is reviewed. The primary aim of the present work is to establish a connection between such equation and the percolation conduction theory.

Phytoclimatic characterization of holm-oak provenances (Quercus ilex L.) in the Central-Northern Iberian Peninsula

This paper presents some contributions to the phytoclimatic characterization of stands of holm-oak (Quercus ilex. L.) in the centre-north of the Iberian Peninsula and the testing of a method of phytoclimatic homologation applicable to the characterization of provenances of the species. For the phytoclimatic characterization, 432 sampling points in the Province of Burgos were considered, corresponding to the centres of cartographic tessellae of actual vegetation in which holm-oak was the principle species of the forest (18,965 ha). The phytoclimatic diagnosis followed the phytoclimatic models of Allué-Andrade. Phytoclimatic territorial models were constructed in digital format on the basis of preliminary territorial factorial estimations, which were used to determine phytoclimatic terns. Based on the establishment of phytoclimatic ambits for the existence of holm-oak stands in Burgos and stratification in accordance with the five phytoclimatic subtypes (VI(IV)1, VI(IV)2, VI(VII), VI(V) and VI), phytoclimatic homologation was performed in three phases of increasing strictness, all based on a comparison of phytoclimatic terns derived from the general and specific phytoclimatic systems. In the strictest homologation, an adequate and territorially compact degree of discrimination was achieved for 2.622.500 ha (Quercus ilex subsp. ballota) and 116.00 ha (Quercus ilex subsp. ilex) in the centre-north of the Iberian Peninsula. The marked edaphic azonality of the species was an important factor in the interpretation of the results.

External field induced crystallization of poly(3-dodecylthiophene)

In order to investigate the effect of external field on the crystallization behavior of poly(3-dodecylthiophene) (P3DDT), the samples were recrystallized with different electrostatic field intensity, different pressure and different solidification direction in temperature gradient field. Measurements of differential scanning calorimetry and X-ray diffraction were operated to characterize these samples for analysis. The results suggest that after recrystallization, whether the external field is added or not, a more compact packing of molecular chains in P3DDT could be obtained without the change of the crystal structure model. Moreover, the addition of electrostatic field has greater effects on the crystallization of rigid main chains than on that of flexible side chains. Merely great pressure field can effect the rearrangements of molecular chains greatly. As for the temperature gradient field induced crystallization, different oriented solidification direction will lead to different effects on the compact degree and perfect degree of molecular chains packing.