Tool State Detection by Harmonic Wavelet and Sample Entropy

It is a fact that acoustic emission(AE) signals contain potentially valuable information for tool wear and breakage monitoring and detection.However,AE stress waves produced in the cutting zone are distorted by the transmission path and the measurement systems,it is difficult to obtain a reliable result by these raw AE data.It is generally known that the process of tool wear belongs to detect weak singularity signals in strong noise.The objective of this paper is to combine Newland Harmonic wavelet and Richman-Moorman(2000) sample entropy for detecting weak singularity signals embedded in strong signals.First,the raw AE signal is decomposed by harmonic wavelet and transformed into the three-dimensional time-frequency mesh map of the harmonic wavelet,at the same time,the contours of the mesh map with log space is induced.Second,the profile map of the three-dimensional time-frequency mesh map is offered,which corresponds to decomposed level on harmonic wavelets.Final,by computing sample entropy in each level,the weak singularity signal can be easily extracted from strong noise.Machining test was carried out on HL-32 NC turning center.This lathe does not have a tailstock.Tungsten carbide finishing tool was used to turn free machining mild steel.The work material was chosen for ease of machining,allowing for generation of surfaces of varying quality without the use of cutting fluids.In turning experiments,the feasibility for tool condition monitoring is demonstrated by 27 kinds of cutting conditions with the sharp tool and the worn tool,54 group data are sampled by AE.The sample entropy of each level of wavelet decomposed for each one of 54 AE datum is computed,wear tool and shaper tool can be distinguished obviously by the sample entropy value at the 12th level,this is a criterion.The proposed research provides a new theoretical basis and a new engineering application on the tool condition monitoring.     

Tailor-Made Coatings for Turbine Applications Using the Triplex Pro 200

In modern jet engines, the efficiency of compressor stages is highly dependent on the clearance between blade tip and casing. To improve efficiency of gas turbines, the gap between the turbine blades and casing has to be minimized. Abradable coatings permit a minimization of the clearance and control of the over-tip leakage by allowing the blade tips to cut into the coating. Thermal sprayed abradables aim at a well-balanced profile of properties relevant for abradable seals. Amongst others these include: abradability, aging resistance, corrosion and oxidation resistance, and bond strength to substrate. Here, abradable coatings consisting of a multiphase material, comprising a metal matrix and a solid lubricant as well as a defined porosity, were developed using the Triplex Pro 200 to increase reproducibility and deposition efficiency. In addition, the influence of the process parameters on coating characteristics (porosity, hardness) and, as a result, erosion properties and abradability was investigated.     

Corrosion processes and their influence on the magnetic flux density of FeNbCuSiB alloys

This paper describes the effect of corrosion process in the magnetic flux density of FeNbCuSiB alloys and correlates with the Si content in the alloys and in the surface oxide layer after a corrosion process. The corrosion resistance of FeNbCuSiB alloys was studied by ordinary weight loss tests, the potentiodynamic polarization technique and spectroscopy impedance. The photoelectron spectroscopy was used in order to identify the compositional changes in the surface oxide layer. Two alloy compositions, Fe_77.5Cu₁Nb₃Si_2.5B₁₆ and Fe₇₃Cu₁Nb₃Si_16.5B_6.5, with different Si content were analyzed in two different conditions, amorphous and crystalline states, respectively. The Fe_77.5Cu₁Nb₃Si_2.5B₁₆ alloy displayed lower corrosion resistance than the Fe₇₃Cu₁Nb₃Si_16.5B_6.5 alloy. The increase of the Si amount in the alloy composition results in an improvement in the corrosion resistance. The enrichment of the Si content on the surface oxide layer was found to be responsible for the improved corrosion resistance. Losses in magnetic properties depend not only on the Si content but also on the structural state.     

Lutein Sequestration and Furanocoumarin Metabolism in Parsnip Webworms Under Different Ultraviolet Light Regimes in the Montane West

Both biotic and abiotic selection pressures can contribute to geographic variation in allelochemical production in plants. We examined furanocoumarin production in western North American populations of Heracleum lanatum and Pastinaca sativa that, at different latitudes and altitudes, experience different ultraviolet (UV) light regimes. Total furanocoumarins and linear furanocoumarins of fruits were negatively correlated with UV irradiance, whereas amounts of angular furanocoumarins, which are generally less phototoxic, were not. Another factor potentially influencing furanocoumarin production is the presence of the parsnip webworm Depressaria pastinacella, (Lepidoptera: Oecophoridae), an herbivore that feeds on reproductive structures of both plant species. These insects sequester lutein from their host plants; this carotenoid acts to ameliorate furanocoumarin toxicity. Although the concentration of lutein in fruits did not vary with UV irradiance, lutein sequestration by sixth instars was positively correlated with UV irradiance. Webworm populations are variably infested with the polyembryonic webworm parasitoid Copidosoma sosares Walker (Hymenoptera: Encyrtidae). H. lanatum fruits from populations with webworms parasitized by C. sosares had lower concentrations of furanocoumarins, with the exception of sphondin, than fruits from plants infested with webworms free from parasitism. Lower levels of these furanocoumarins may reduce negative effects on the fitness of this parasitoid. In contrast with the variation in furanocoumarin content, the ability of webworms to metabolize furanocoumarins by cytochrome P450 did not differ significantly among populations from New Mexico to Alberta.     

Toxicity of Aflatoxin B1 to Helicoverpa zea and Bioactivation by Cytochrome P450 Monooxygenases

Infestation of corn (Zea mays) by corn earworm (Helicoverpa zea) predisposes the plant to infection by Aspergillus fungi and concomitant contamination with the carcinogenic mycotoxin aflatoxin B1 (AFB1). Although effects of ingesting AFB1 are well documented in livestock and humans, the effects on insects that naturally encounter this mycotoxin are not as well defined. Toxicity of AFB1 to different stages of H. zea (first, third, and fifth instars) was evaluated with artificial diets containing varying concentrations. Although not acutely toxic at low concentrations (1−20 ng/g), AFB1 had significant chronic effects, including protracted development, increased mortality, decreased pupation rate, and reduced pupal weight. Sensitivity varied with developmental stage; whereas intermediate concentrations (200 ng/g) caused complete mortality in first instars, this same concentration had no detectable adverse effects on larvae encountering AFB1 in fifth instar. Fifth instars consuming AFB1 at higher concentrations (1 μg/g), however, displayed morphological deformities at pupation. That cytochrome P450 monooxygenases (P450s) are involved in the bioactivation of aflatoxin in this species is evidenced by the effects of piperonyl butoxide (PBO), a known P450 inhibitor, on toxicity; whereas no fourth instars pupated in the presence of 1 μg/g AFB1 in the diet, the presence of 0.1% PBO increased the pupation rate to 71.7%. Pupation rates of both fourth and fifth instars on diets containing 1 μg/g AFB1 also increased significantly in the presence of PBO. Effects of phenobarbital, a P450 inducer, on AFB1 toxicity were less dramatic than those of PBO. Collectively, these findings indicate that, as in many other vertebrates and invertebrates, toxicity of AFB1 to H. zea results from P450-mediated metabolic bioactivation.An erratum to this article can be found at     

油田开发静动态水淹程度评价方法概述

油田开发静动态水淹程度技术包含单井油层垂向水淹程度精细静态评价和开发区块合采井水淹程度动态评价，是一项系统技术。该文简要介绍了静态评价采用的分析方法及效果；重点阐述了油田开发动态水淹程度评价技术的原理、分析流程、计算方法和优缺点。对油田开发后期油层静动态评价提供了一种有效手段。     

Publisher 2003对象模型简介

通过本文可以在开始使用Micmsoft Office Publisher 2003对象模型自动化Publisher中强大的打印和Web发布功能之前，学习有经验的程序员需要了解的内容。     

Severe cardiomyopathy in mice lacking dystrophin and MyoD

PRINTS is a diagnostic collection of protein fingerprints. Fingerprints exploit groups of motifs to build characteristic family signatures, offering improved diagnostic reliability over single-motif approaches by virtue of the mutual context provided by motif neighbours. Around 1000 fingerprints have now been created and stored in PRINTS. The September 1998 release (version 20.0), encodes approximately 5700 motifs, covering a range of globular and membrane proteins, modular polypeptides and so on. The database is accessible via the DbBrowser Web Server at http://www.biochem.ucl.ac.uk/bsm/dbbrowser /. In addition to supporting its continued growth, recent enhancements to the resource include a BLAST server, and more efficient fingerprint search software, with improved statistics for estimating the reliability of retrieved matches. Current efforts are focused on the design of more automated methods for database maintenance; implementation of an object-relational schema for efficient data management; and integration with PROSITE, profiles, Pfam and ProDom, as part of the international InterPro project, which aims to unify protein pattern databases and offer improved tools for genome analysis.     

New insights into the mechanism of CVD diamond growth: Single crystal diamond in MW PECVD reactors

CVD Diamond can now be deposited either in the form of single crystal homoepitaxial layers, or as polycrystalline films with crystal sizes ranging from mm, μm or nm, and with a variety of growth rates up to 100s of μm h^− 1 depending upon deposition conditions. We previously developed a model which provides a coherent and unified picture that accounts for the observed growth rate, morphology, and crystal sizes, of all of these types of diamond. The model is based on competition between H atoms, CH₃ radicals and other C₁ radical species reacting with dangling bonds on the diamond surface. The approach leads to formulae for the diamond growth rate G and average crystallite size <d> that use as parameters the concentrations of H and CH_x (0 ≤ x ≤ 3) near the growing diamond surface. We now extend the model to show that the basic approach can help explain the growth conditions required for single crystal diamond films at pressures of 100–200 Torr and high power densities.