Wear rates in urban rail systems

A significant part of maintenance costs in urban rail systems (metro, tram, light rapid transit/light metro) is due to wheel-rail wear. Wear rates - measured for example as depth of wear per kilometre run (rolling stock) or per train passage (rails) - depend in a complex manner on several influence factors. Among the most important are key design factors of the rolling stock (wheel profiles, suspension characteristics), of the track (distribution of curve radii, characteristics of switches and crossings, rail profiles), of the wheel-rail interface (lubrication, materials in contact, ambient characteristics), and of operations (frequency of traction and braking, trainset inversion policy, maintenance policy etc.). When designing an urban rail system, all of these factors have to be under control in order to limit the costs due to wheel/rail reprofiling/grinding and replacement. The state of the art allows the calculation of wear rates given quantitative input regarding the above factors. However, it is difficult to find in the literature experimental values for calibration of wear models and indications on what is a reasonable state-of-the-art wear rate for any given type of urban rail system. In this paper we present a structured analysis of flange wear rates found in the literature and derived from the experience of the authors, for a variety of cases, including metros and mainline rail systems. We compare the wear rates and explain their relationship with the influence factors. We then relate the wear rates with the needs in terms of wheel reprofiling/replacement. We estimate ranges for the calibration coefficients of wear models. We present the results in a way as to allow the designer of urban rail systems to derive values for target wear rates according to their specific conditions without the need for complex simulations

Information Length and Localization in One Dimension

The scaling properties of the wave functions in finite samples of the one dimensional Anderson model are analyzed. The states have been characterized using a new form of the information or entropic length, and compared with analytical results obtained by assuming an exponential envelope function. A perfect agreement is obtained already for systems of $10^3$--$10^4$ sites over a very wide range of disorder parameter $10^{-4}<W<10^4$. Implications for higher dimensions are also presented.Comment: 11 pages (+3 Figures upon request), Plain TE

Biocompatible electrospun polycaprolactone-polyaniline scaffold treated with atmospheric plasma to improve hydrophilicity

Conductive polymers (CPs) have recently been applied in the development of scaffolds for tissue engineering applications in attempt to induce additional cues able to enhance tissue growth. Polyaniline (PANI) is one of the most widely studied CPs, but it requires to be blended with other polymers in order to be processed through conventional technologies. Here, we propose the fabrication of nanofibers based on a polycaprolactone (PCL)-PANI blend obtained using electro-spinning technology. An extracellular matrix-like fibrous substrate was obtained showing a good stability in the physiological environment (37 °C in PBS solution up 7 days). However, since the high hydrophobicity of the PCL-PANI mats (133.5 ± 2.2°) could negatively affect the biological re-sponse, a treatment with atmospheric plasma was applied on the nanofibrous mats, obtaining a hydrophilic surface (67.1 ± 2°). In vitro tests were performed to confirm the viability and the physi-ological-like morphology of human foreskin fibroblast (HFF-1) cells cultured on the plasma treated PCL-PANI nanofibrous scaffolds

Quality maintenance performance and resistance to Tribolium castaneum and Plodia interpunctella penetration of an alternative packaging material for semolina

Insect attacks to food packages are a major concern for food producers, who are often blamed for being responsible for the occurrence of contamination which seriously affects the image of the company. Wheat semolina is commonly packed in paper bags, which do not always offer sufficient protection against insect pests. The present research evaluated the performance of a new packaging alternative, consisting of paper laminated with polypropylene (P+CPP), in terms of resistance to penetration by two common cereal product pests, namely Tribolium castaneum and Plodia interpunctella, and quality maintenance of the packaged product. Neither of the two pest species tested were able to pierce the P+CPP, while no differences were observed in the time required to penetrate other materials. Moreover, quality parameters, namely pH, acidity and color, did not differ significantly among samples packed in different materials. The new P+CPP combination is a promising alternative for the packaging of semolina, because it offers improved protection against pests compared with conventional materials, while maintaining the paper appearance of traditional packaging

Evaluation of Variability in the Sweet Orange Germplasm through Next Generation Clonal Fingerprinting

The great phenotypic variability characterizing the sweet orange [Citrus sinensis(L.) Osbeck] germplasm arises from spontaneous bud mutations, causing a diversification into major groups (common, Navel and blood oranges). A huge divergence also occurred within each varietal group. The genetic basis of such variability, also including nutritional and qualitative traits (ripening time, colour, fruit shape, acidity, sugars), is currently uncharacterized, and therefore not exploitable. With the aim of describing the somatic mutation events in the sweet orange group a deep-sequencing of 20 Italian and foreign accessions was performed by Illumina platform, allowing the identification of single nucleotide polymorphisms (SNPs), structural variants (SVs) and large deletions, specific to each varietal group or clone-specific. A subset of SNPs used for the design of two 384 SNP - GoldenGate Assays allowed to genotype 225 CREA sweet orange accessions. The developed markers represent the first reliable molecular tools able to unambiguously fingerprint each somatic mutant. Moreover, they might be used to associate mutations with phenotypic traits, and are a powerful tool for traceability. By using the GoldenGate assay, we have been able to fingerprint several blood orange clones starting from DNAs isolated from leaves or juice. These tools will potentially provide the consumer with a guarantee on the quality and origin of juices, avoiding eventual frauds

Coexistence of orbital and quantum critical magnetoresistance in FeSe1−x_{1-x}Sx_{x}

The recent discovery of a non-magnetic nematic quantum critical point (QCP) in the iron chalcogenide family FeSe$_{1-x}$S$_{x}$ has raised the prospect of investigating, in isolation, the role of nematicity on the electronic properties of correlated metals. Here we report a detailed study of the normal state transverse magnetoresistance (MR) in FeSe$_{1-x}$S$_{x}$ for a series of S concentrations spanning the nematic QCP. For all temperatures and \textit{x}-values studied, the MR can be decomposed into two distinct components: one that varies quadratically in magnetic field strength $\mu_{0}\textit{H}$ and one that follows precisely the quadrature scaling form recently reported in metals at or close to a QCP and characterized by a \textit{H}-linear MR over an extended field range. The two components evolve systematically with both temperature and S-substitution in a manner that is determined by their proximity to the nematic QCP. This study thus reveals unambiguously the coexistence of two independent charge sectors in a quantum critical system. Moreover, the quantum critical component of the MR is found to be less sensitive to disorder than the quadratic (orbital) MR, suggesting that detection of the latter in previous MR studies of metals near a QCP may have been obscured.Comment: 19 pages (including Supplemental Material), 12 figure

Educating and Empowering Elders: Improving the Health of Senior Latino Diabetics through Community Collaboration

According to the American Diabetes Association (ADA), diabetes is the sixth leading cause of death among Americans.1 As of 2005, estimates indicate 20.8 million people – 7 percent of the population – afflicted by diabetes, 6.2 million of which are undiagnosed. 1 While diabetes is a growing problem for the United States as a whole, older, poverty-stricken Latinos and other minority groups have felt the encumbrance of this trend most intensely.2 In Massachusetts, the burden of diabetes among Caribbean Latinos is 11.8 percent, which is 2.5 times greater than the prevalence for the majority of the population in the state (4.7 percent).3 The age-adjusted rate for Latinos with diabetes is 36.25 per 100,000—76 percent higher than the state rate of 20.56.4 If this trend continues, the prevalence of type 2 diabetes nationwide will skyrocket, as Hispanics constitute the largest and fastest-growing minority in the United States.