WAVELETS AND PRINCIPAL COMPONENT ANALYSIS METHOD FOR VIBRATION MONITORING OF ROTATING MACHINERY

Fault diagnosis is playing today a crucial role in industrial systems. To improve reliability, safety and efficiency advanced monitoring methods have become increasingly important for many systems. The vibration analysis method is essential in improving condition monitoring and fault diagnosis of rotating machinery. Effective utilization of vibration signals depends upon effectiveness of applied signal processing techniques. In this paper, fault diagnosis is performed using a combination between Wavelet Transform (WT) and Principal Component Analysis (PCA). The WT is employed to decompose the vibration signal of measurements data in different frequency bands. The obtained decomposition levels are used as the input to the PCA method for fault identification using, respectively, the Q-statistic, also called Squared Prediction Error (SPE) and the Q-contribution. Clearly, useful information about the fault can be contained in some levels of wavelet decomposition. For this purpose, the Q-contribution is used as an evaluation criterion to select the optimal level, which contains the maximum information.Associated to spectral analysis and envelope analysis, it allows clear visualization of fault frequencies. The objective of this method is to obtain the information contained in the measured data. The monitoring results using real sensor measurements from a pilot scale are presented and discussed

Wave loads and stability of new foundation structure for offshore wind turbines made of Ocean Brick System (OBS)

The Ocean Brick System (OBS) is a modular system consisting of hollow concrete precast blocs (10m x 10m x 10m) piled up like cubes and interconnected to create a stiff, light and strong structure which can be used for artificial islands, artificial reefs, elevation of vulnerable low lands, deep water ports, breakwaters and foundation of offshore wind turbines. The paper focuses on the experimental results on the wave loading and the stability of the OBS used as a foundation of the support structure of offshore wind turbines. Diagrams for the prediction of total horizontal forces, vertical forces and overturning moments induced by irregular waves on the OB-structure are derived and verified through additional stability tests and stability analysis

How to prioritize work-related psychosocial factors impacting mental health? Regression and random forest approaches

International audienc

Hydraulic performance of elastomeric bonded permeable revetments and subsoil response to wave loads

Elastomeric bonded permeable revetments, also called PBA (Polyurethane bonded aggregate) revetments, are highly porous structures made of mineral aggregates (e.g. crushed stones) which are durably and elastically bonded by polyurethane (PU). Despite their numerous advantages as compared to conventional revetments and the large experience available from more than 25 pilot projects, physically-based design formulae to predict their hydraulic performance, wave loading and response are still lacking. Therefore, the present study aims at improving the understanding of the processes involved in the interaction between wave, revetment and foundation, based on large-scale model tests performed in the Coastal Research Centre (FZK), Hannover/Germany, and to provide prediction formulae/diagrams. This paper is focused on the prediction of the hydraulic performance (wave reflection, wave runup and run-down) and the response of the sand core (pore pressure) beneath the revetment for a wide range of wave conditions, including the analysis of an observed failure due to transient soil liquefaction.BASF-Elastogran Gmb

Proposal for an ecofriendly and economic strategy for efficient radioiodination of coumarin derivatives

Combination of the calculation of reactivity descriptors and the cold iodine test for some coumarin derivatives was used in order to optimize the radioiodination reaction. The strongly nucleophilic predicted coumarins were subjected to the action of cold iodine. With two coumarins substituted at 3 by the 2-hydroxybenzoyl group, iodination did not occur but a product of intramolecular heterocyclization was obtained. This strategy is useful for economic and environmentally friendly radioiodination.publishe

Melghirimyces thermohalophilus sp. nov., a novel thermoactinomycete isolated from an Algerian salt lake

A novel filamentous bacterium designated Nari11AT was isolated from soil collected from a salt lake named Chott Melghir located in south east of Algeria. The strain is an aerobic, halophilic, thermotolerant, Gram-positive bacterium, growing at NaCl concentrations between 5 and 20% w/v and temperature and pH ranges between 43-60 °C and 5.0-10.0, respectively. The major fatty acids were isoC15:0, anteisoC15:0 and isoC17:0. The G+C value was 53.4 mol %. LL-diaminopimelic acid was the diamino acid of the peptidoglycan. The major menaquinone was MK-7, but MK-6 and MK-8 were also present in trace amounts. The polar lipids' profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and three unidentified phospholipids. Results of molecular and phenotypic analysis led to the description of the strain as a new member to the genus Melghirimyces, family Thermoactinomycetaceae. Strain Nari11AT shows a 16S rRNA gene sequence similarity of 96.7% with Melghirimyces algeriensis. On the basis of phenotypic, physiological and phylogenetical data the type strain Nari11AT (DSM 45514T =CCUG 60050T) represents a new species for which the name Melghirimyces thermohalophilus sp. nov., is proposed

Level of kidney function as a risk factor for atherosclerotic cardiovascular outcomes in the community

AbstractObjectivesThe goal of this study was to determine whether the level of kidney function is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD) outcomes in the Atherosclerosis Risk in Communities (ARIC) study, a prospective cohort study of subjects aged 45 to 64 years.BackgroundThe level of kidney function is now recognized as a risk factor for ASCVD outcomes in patients at high risk for ASCVD, but it remains unknown whether the level of kidney function is a risk factor for ASCVD outcomes in the community.MethodsCox proportional-hazards regression was used to evaluate the association of glomerular filtration rate (GFR) with ASCVD after adjustment for the major ASCVD risk factors in 15,350 subjects. We searched for nonlinear relationships between GFR and ASCVD.ResultsDuring a mean follow-up time of 6.2 years, 965 (6.3%) of subjects had ASCVD events. Subjects with GFR of 15 to 59 ml/min/1.73 m2(n = 444, hazard ratio 1.38 [1.02, 1.87]) and 60 to 89 ml/min/1.73 m2(n = 7,665, hazard ratio 1.16 [1.00, 1.34]) had an increased adjusted risk of ASCVD compared with subjects with GFR of 90 to 150 ml/min/1.73 m2. Each 10 ml/min/1.73 m2lower GFR was associated with an adjusted hazard ratio of 1.05 (1.02, 1.09), 1.07 (1.01, 1.12), and 1.06 (0.99, 1.13) for ASCVD, de novo ASCVD, and recurrent ASCVD, respectively. A nonlinear model did not fit the data better than a linear model.ConclusionsThe level of GFR is an independent risk factor for ASCVD and de novo ASCVD in the ARIC study

Aspirin Use and Incident Cardiovascular Disease, Kidney Failure, and Death in Stable Kidney Transplant Recipients: A Post Hoc Analysis of the Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial

Cardiovascular disease (CVD) is the leading cause of death in kidney transplant recipients. Whether aspirin may reduce the risk for CVD, death, and kidney failure outcomes is uncertain

Valorization of fine bran of Algerian durum wheat varieties in the diet of ruminants

The feed value of the fine bran of durum wheat varieties cultivated in Algeria have as characteristics an average content of total nitrogen of 13.2% of dry matter (DM), a fat content of 2.4% of DM and minerals content of 2.8% of DM. These various chemical compounds values confer less fodder units and digestible proteins than those of durum wheat fine bran from Europeans varieties