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11.
12.
A digital filter-based approach to the remote condition monitoring of railway turnouts 总被引:2,自引:0,他引:2
Railway operations in Europe have changed dramatically since the early 1990s, partly as a result of new European Union Directives. Performance targets have become more and more exacting, due to reductions in state support for railways and the need to increasing traffic. More intensive operations also place greater demands on the hardware of the railway. This is true for both rolling stock and infrastructure subsystems and components, particularly so in the case of the latter where the time available for maintenance is being reduced. The authors of this paper focus on the railway infrastructure, and more specifically on points. These are critical elements whose reliability is key to the operation of the whole system. Using intelligent monitoring systems, it is possible to predict problems and enable quick recovery before component failures disrupt operations. The authors have studied the application of remote condition monitoring to point mechanisms and their operation, and have identified algorithms which may be used to identify incipient failures. In this paper, the authors propose a Kalman filter for the linear discrete data filtering problem encountered when using current sensor data in a point condition monitoring system. The reason for applying Kalman filtering in this study was to increase the reliability of the model presented to the rule-based decision mechanism. 相似文献
13.
Sebastián Velasquez Néstor Peña Juan Carlos Bohórquez Nelson Gutiérrez 《International Journal of Food Properties》2018,21(1):1332-1343
The complex permittivity for four processing stages of coffee: coffee cherries, pulped coffee, green coffee, and roasted coffee was obtained and divided into two groups. The wet group is constituted by cherry and pulped coffee, and the dry group by green and roasted coffee. The wet group presented a dielectric constant between 64 and 43, and a loss factor between 34 and 12. The dry group has values oscillating between 1.55 and 1.1 for the dielectric constant, and 0.037 and 0.005 for the loss factor. The permittivity difference between the wet and dry groups suggests the dependence of the coffee permittivity on the water content, along with the presence of other polar compounds. A decaying response for the dielectric constant was seen, with a proportion of 30:1 from the wet to the dry group. The loss factor presents a convex response for the wet group and a constant response for the dry group with a factor of 500 to a 100:1 from the wet to the dry group. A set of 18 samples at every stage was used to estimate the moisture content by partial least squares. The Meyer and Schilz coefficient was used for these models, that resulted in prediction errors of 2.8% and 3.8% when compared to the stage mean moisture content for the wet group. The dry group resulted in errors of 21% and 89.7%. These results indicate that the complex permittivity of coffee is capable of estimating physicochemical variables as the moisture content of the beans at distinct processing stages. 相似文献
14.
H Arenas Márquez F López Neblina H Barrera Torres MR Flores Márquez 《Canadian Metallurgical Quarterly》1994,59(1):49-51
The presence of an earlier latency of 12 msec of a somato-sensory evoked potential elicited by the stimulation of the median nerve at the wrist was discovered in 1963 by Liberson and Kim. They suggested its origin in the cervical spine or in the brain stem and possibly the cerebellum. Liberson, Voris and Uematsu recorded directly these potentials from the cervical spine and from the mesencephalon during surgery for pain in 1969 and published some of the findings in 1970. Cracco and Bickford confirmed in 1968 the findings of Liberson and Kim. 相似文献
15.
Natalia Cullell Cristina Gallego-Fbrega Jara Crcel-Mrquez Elena Muio Laia Lluci-Carol Miquel Lleds Jesús M. Martín-Campos Jessica Molina Laura Casas Marta Almeria Israel Fernndez-Cadenas Jerzy Krupinski 《International journal of molecular sciences》2022,23(6)
Small vessel strokes (SVS) and intracerebral haemorrhages (ICH) are acute outcomes of cerebral small vessel disease (SVD). Genetic studies combining both phenotypes have identified three loci associated with both traits. However, the genetic cis-regulation at the protein level associated with SVD has not been studied before. We performed a proteome-wide association study (PWAS) using FUSION to integrate a genome-wide association study (GWAS) and brain proteomic data to discover the common mechanisms regulating both SVS and ICH. Dorsolateral prefrontal cortex (dPFC) brain proteomes from the ROS/MAP study (N = 376 subjects and 1443 proteins) and the summary statistics for the SVS GWAS from the MEGASTROKE study (N = 237,511) and multi-trait analysis of GWAS (MTAG)-ICH–SVS from Chung et al. (N = 240,269) were selected. We performed PWAS and then a co-localization analysis with COLOC. The significant and nominal results were validated using a replication dPFC proteome (N = 152). The replicated results (q-value < 0.05) were further investigated for the causality relationship using summary data-based Mendelian randomization (SMR). One protein (ICA1L) was significantly associated with SVS (z-score = −4.42 and p-value = 9.6 × 10−6) and non-lobar ICH (z-score = −4.8 and p-value = 1.58 × 10−6) in the discovery PWAS, with a high co-localization posterior probability of 4. In the validation PWAS, ICA1L remained significantly associated with both traits. The SMR results for ICA1L indicated a causal association of protein expression levels in the brain with SVS (p-value = 3.66 × 10−5) and non-lobar ICH (p-value = 1.81 × 10−5). Our results show that the association of ICA1L with SVS and non-lobar ICH is conditioned by the cis-regulation of its protein levels in the brain. 相似文献
16.
Andrés L. Márquez María P. Pérez Jorge R. Wagner 《Journal of the American Oil Chemists' Society》2013,90(4):467-473
The objective of this work was to develop a corrected method for solid fat content estimation by differential scanning calorimetry (DSC), as important differences are usually observed between the results given by DSC and pulsed nuclear magnetic resonance (NMR). Cold storage after full melting of fats was necessary to avoid the appearance of exothermic peaks in the modulated temperature DSC thermograms, in order to make an appropriate estimation of melting energy. Different fats were analyzed by NMR and DSC, obtaining considerably higher solid fat content values with the latter, uncorrected method. These differences were attributed to the fact that consumed energy per unit of melted mass tends to increase with the increase of the melting temperature of each fraction of the fats. A linear correlation between melting enthalpy and melting point of different triglycerides was used to estimate the energy per unit of mass consumed at each temperature. From these data, an estimated transformation of melting energy into melted mass was performed and new solid fat content values were calculated. The results obtained from this correction were much closer to the measurements made by NMR, in comparison to the uncorrected DSC method. 相似文献
17.
Summary Electropolymerization of o-(CH3O)2C6H4 (Veratrole) in dry acetonitrile/tetrabutylammonium tetrafluoroborate at platinum electrode, yields a green polymeric conducting solid. As the pressure is increased, the material becomes more conductive, but sharp changes towards lower conductivity occur at 4.2 and 6.2 metric tons pressure, probably due to phase transitions. The photoconductivity shows an exponential increase as temperature is increased, but it shows reversible changes at 200 K, 225 K and 250 K during slow warming, also attributable to phase transitions. Photoconductivity of Polyveratrole increases with the radiation frequency, being higher under blue light than under red of infrared radiation and there is a linear increase of photoconductivity with radiation density. Conductivity transients show that the conductivity increases exponentially with time to the saturation point within few minutes, and it also decreases exponentially when the light is turned off and the circuit is open. This behaviour can be explained by formation and encounter of electron and hole as current carriers. A preliminary study indicates a piezoelectric effect for the material. absorption spectroscopy allowed the measurements of the material band gap. 相似文献
18.
Jesús Enrique Sosa-Márquez Lorena Zamarrón-Montes Sion Federico Olive-Méndez Francisco Espinosa-Magaña 《Journal of the American Ceramic Society》2022,105(9):5956-5965
Pure and Mn-doped lithium tantalate nanofibers, with Mn concentrations of 1%, 2.5%, and 5%, were synthesized by the electrospinning method. The morphology, microstructure, and crystal structure of as-spun and annealed composite nanofibers were characterized by scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. Raman spectroscopy has shown to be a powerful tool to detect either local variations or changes of the whole structure. Position and width of one Raman line can be used as markers of a structural change. Some vibrational modes are especially associated with the site of Li or Ta ions and so, they can be affected by the introduction of dopant ions. Any damages or local changes in the microstructure can be detected by a line broadening. With the use of Raman spectroscopy, the sites where Mn ions enter the doped structures were established by recording the shift and broadening of peaks in Mn-doped structures with respect to pure lithium tantalate. Thus it was proven that Mn ions enter the Li sites for low Mn concentration and, on the other hand, for higher concentrations, the dopant substitutes Li and Ta sites. First-principles calculations were performed within the density functional theory, including lattice-dynamic calculations of the phonon modes at the zone center (Γ point), for the pure structure, to find the irreducible representation of the modes. 相似文献
19.
Luz Bertoia Jorge R. Wagner Andrés L. Márquez 《Journal of the American Oil Chemists' Society》2020,97(10):1071-1081
The objective was to study the microstructure and freeze–thaw stability of margarine-like emulsions formulated with vegetable fats using differential scanning calorimetry. Emulsions were prepared with 20% w/w dispersed aqueous phase and a continuous lipid phase composed by coconut oil (CO) and/or palm oil (PO) plus polyglycerol polyricinoleate (PGPR) as emulsifier. Mean temperature (TM) and crystallization enthalpy (ΔHc) were obtained from the exothermic peaks corresponding to freezing of aqueous phase. Successive cooling–heating–cooling cycles were applied to analyze changes in the exothermic peak. The emulsion prepared with CO (without PO) and 1% w/w PGPR in lipid phase showed higher water droplets size (TM = −44.8 ± 0.1 °C) and lower quantity of stabilized aqueous phase (ΔHc = 28.9 ± 1.2 J g−1) prior to application of temperature cycles, while coalescence and (presumably) water transfer processes occurred during the treatment. The use of 2% w/w PGPR was sufficient to accomplish full stabilization of aqueous phase (TM = −45.9 ± 0.1 °C; ΔHc = 42.6 ± 0.3 J g−1) before and after the freeze–thaw treatment. The total or partial (50%) substitution of CO by PO in emulsions with 1% w/w PGPR also improved the stability of the system, exhibiting slight microstructural changes. This enhanced stability would be linked to reduced water droplets size because of more rapid crystallization of lipid phase and immobilization of aqueous phase after emulsion preparation. In conclusion, it is possible to obtain margarine-like emulsions prepared with CO and/or PO using relatively low emulsifier concentration and maintaining a desired microstructure after freeze-thawing if the percentage ratio of both fats is controlled. 相似文献
20.
Incorporation of chloramphenicol and captopril into poly(GL)‐b‐poly(GL‐co‐TMC‐co‐CL)‐b‐poly(GL) monofilar surgical sutures 下载免费PDF全文
Yolanda Márquez Tània Cabral Alice Lorenzetti Lourdes Franco Pau Turon Luís J. del Valle Jordi Puiggalí 《应用聚合物科学杂志》2017,134(17)
Incorporation of chloramphenicol and captopril into coated and uncoated monofilament sutures was evaluated, as well as the derived bactericide and wound healing effects. To this end, a commercially available suture and an amorphous random copolymer constituted by trimethylene carbonate and lactide units were considered. The suture had a segmented architecture based on polyglycolide hard blocks and a soft block constituted by glycolide, trimethylene carbonate and ε‐caprolactone units. Chloramphenicol was better loaded when the coating copolymer was employed due to its protective effect whereas captopril showed an opposite behavior due to partial solubilization during immersion in the coating bath. Interestingly, the release behavior was very different for the two studied drugs since a significant retention of chloramphenicol was always detected, suggesting the establishment of interactions between drug and copolymers. On the other hand, delivery of captopril showed a typical dose dependent behavior. A low in vitro toxicity of the two drugs was determined considering both epithelial‐like and fibroblast‐like cells. Bactericide effect of chloramphenicol against Gram‐negative and Gram‐positive bacteria was demonstrated at a dose that was non‐toxic for all assayed cells. An accelerating wound healing effect of captopril was also demonstrated for early events. In this case, the use of a coating copolymer was fundamental to avoid cytotoxic effects on highly loaded sutures. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44762. 相似文献