Acoustic measurement of lubricant-film thickness distribution in ball bearings

An oil-film thickness monitoring system capable of providing an early warning of lubrication failure in rolling element bearings has been developed. The system is used to measure the lubricant-film thickness in a conventional deep groove ball bearing (shaft diameter 80 mm, ball diameter 12.7 mm). The measurement system comprises a 50 MHz broadband ultrasonic focused transducer mounted on the static outer raceway of the bearing. Typically the lubricant-films in rolling element bearings are between 0.1-1.0 μm in thickness and so are significantly smaller than the ultrasonic wavelength. A quasistatic spring model is used to calculate oil-film thickness from the measured reflection coefficient data. An accurate triggering system has been developed to enable multiple reflection coefficient measurements to be made as the contact ellipse sweeps over the measurement location. Experiments are described in which the loading conditions and rotational speed are varied. Lubricant-film thickness distributions measured ultrasonically are described and are shown to agree well with the predictions from classical elastohydrodynamic (EHD) lubrication theory, particularly at high radial loads and low rotary speeds. A range of parameters affecting the performance of the measurement are discussed and the limits of operation of the measurement technique defined. © 2006 Acoustical Society of America

Timeshare Owners’ Perceptions of and Preferred Ways of Participating in Tourism Planning

Purpose To explore the impact of prostate cancer treatment on: (a) the experience of symptoms (i.e. sexual, urinary, and bowel), and (b) perceived health state of men with prostate cancer one month following their radiation treatment. Methods A prospective pre-test–post-test descriptive survey was conducted on a convenience sample of 73 men with prostate cancer who were recruited from a Regional Cancer Centre in Southwestern Ontario, Canada. Participants receiving radiation treatment (brachy therapy, high dose radiation [HDR] and external beam radiation [EBR], or EBR alone) completed a questionnaire that elicited information pertaining to quality of life (QOL), symptom experiences, and perceived health state prior to, and one month after completion of their radiation treatment. Results Post-treatment scores showed increased problems with urinary bother (ppp=0.002) and function (p=0.001), and sexual function (p Discussion Our findings suggest that prostate cancer treatment presents a challenge with regard to symptom experiences and perceived health state in men with prostate cancer. Therefore, strategies for patient education to assist men to cope with their symptoms and to provide them with support in the initial weeks following treatment are discussed

Solving random diffusion models with nonlinear perturbations by the Wiener-Hermite expansion method

[EN] This paper deals with the construction of approximate series solutions of random nonlinear diffusion equations where nonlinearity is considered by means of a frank small parameter and uncertainty is introduced through white noise in the forcing term. For the simpler but important case in which the diffusion coefficient is time independent, we provide a Gaussian approximation of the solution stochastic process by taking advantage of the Wiener¿Hermite expansion together with the perturbation method. In addition, approximations of the main statistical functions associated with a solution, such as the mean and variance, are computed. Numerical values of these functions are compared with respect to those obtained by applying the Runge¿Kutta second-order stochastic scheme as an illustrative example.This work was partially supported by the Spanish M.C.Y.T. and FEDER grants MTM2009-08587, TRA2007-68006-C02-02, DPI2010-20891-C02-01 as well as the Universidad Politécnica de Valencia grant PAID-06-09 (ref. 2588).Cortés López, JC.; Romero Bauset, JV.; Roselló Ferragud, MD.; Santamaría Navarro, C. (2011). Solving random diffusion models with nonlinear perturbations by the Wiener-Hermite expansion method. Computers and Mathematics with Applications. 61(8):1946-1950. https://doi.org/10.1016/j.camwa.2010.07.057S1946195061

Population balances in case of crossing characteristic curves: Application to T-cells immune response

The progression of a cell population where each individual is characterized by the value of an internal variable varying with time (e.g. size, weight, and protein concentration) is typically modeled by a Population Balance Equation, a first order linear hyperbolic partial differential equation. The characteristics described by internal variables usually vary monotonically with the passage of time. A particular difficulty appears when the characteristic curves exhibit different slopes from each other and therefore cross each other at certain times. In particular such crossing phenomenon occurs during T-cells immune response when the concentrations of protein expressions depend upon each other and also when some global protein (e.g. Interleukin signals) is also involved which is shared by all T-cells. At these crossing points, the linear advection equation is not possible by using the classical way of hyperbolic conservation laws. Therefore, a new Transport Method is introduced in this article which allowed us to find the population density function for such processes. The newly developed Transport method (TM) is shown to work in the case of crossing and to provide a smooth solution at the crossing points in contrast to the classical PDF techniques.Comment: 18 pages, 10 figure

A bi-directional relationship between obesity and health-related quality of life : evidence from the longitudinal AusDiab study

Objective: To assess the prospective relationship between obesity and health-related quality of life, including a novel assessment of the impact of health-related quality of life on weight gain.Design and setting: Longitudinal, national, population-based Australian Diabetes, Obesity and Lifestyle (AusDiab) study, with surveys conducted in 1999/2000 and 2004/2005.Participants: A total of 5985 men and women aged 25 years at study entry.Main outcome measure(s): At both time points, height, weight and waist circumference were measured and self-report data on health-related quality of life from the SF-36 questionnaire were obtained. Cross-sectional and bi-directional, prospective associations between obesity categories and health-related quality of life were assessed.Results: Higher body mass index (BMI) at baseline was associated with deterioration in health-related quality of life over 5 years for seven of the eight health-related quality of life domains in women (all P0.01, with the exception of mental health, P&gt;0.05), and six out of eight in men (all P&lt;0.05, with the exception of role-emotional, P=0.055, and mental health, P&gt;0.05). Each of the quality-of-life domains related to mental health as well as the mental component summary were inversely associated with BMI change (all P&lt;0.0001 for women and P0.01 for men), with the exception of vitality, which was significant in women only (P=0.008). For the physical domains, change in BMI was inversely associated with baseline general health in women only (P=0.023).Conclusions: Obesity was associated with a deterioration in health-related quality of life (including both physical and mental health domains) in this cohort of Australian adults followed over 5 years. Health-related quality of life was also a predictor of weight gain over 5 years, indicating a bi-directional association between obesity and health-related quality of life. The identification of those with poor health-related quality of life may be important in assessing the risk of future weight gain, and a focus on health-related quality of life may be beneficial in weight management strategies.<br /

Flexible and Efficient Computer-Aided Design (CAD) Tool for Advanced Comb-Line Rectangular Waveguide Filters

[EN] A very flexible and efficient computer-aided design (CAD) tool, specifically suited for advanced comb-line rectangular waveguide filters, is presented in this work. The developed software tool, which makes use of a full-wave analysis technique based on the Boundary Integral-Resonant Mode Expansion method, allows loading the considered comb-line resonators with any number of radially symmetrical partial-height metallic posts. The implemented CAD tool also allows dealing with coupling windows of arbitrary cross-section, thus drastically enhancing the flexibility of the CAD process. The excitation of the analyzed components, which is performed using generalized coaxial probes, has also been integrated in the implemented software tool, thus achieving a full-wave electromagnetic characterization of the whole component. Furthermore, a novel simple procedure to efficiently connect all the obtained wide-band matrices is proposed. To validate the accuracy and efficiency of this novel CAD tool, several new designs concerning advanced band-pass comb-line waveguide filters are presented. The accuracy of the developed CAD tool has been successfully validated by comparing the obtained results with numerical data provided by a commercial tool based on the finite-element method. (C) 2015 Wiley Periodicals, Inc.This work has been supported by the Ministerio de Economia y Competitividad, Spanish Government, under the Research Projects TEC2013-47037-C5-1-R and TEC2013-47037-C5-4-R, as well as by the FP7 PCIG11-2012-322162 Marie Curie CIG grant.San Blas Oltra, ÁA.; Vidal Pantaleoni, A.; Müller, A.; Soto Pacheco, P.; Mira Pérez, FE.; Pérez Soler, FJ.; Gimeno Martinez, B.... (2015). Flexible and Efficient Computer-Aided Design (CAD) Tool for Advanced Comb-Line Rectangular Waveguide Filters. International Journal of RF and Microwave Computer-Aided Engineering. 25(8):696-708. https://doi.org/10.1002/mmce.20908S69670825

The Extreme Small Scales: Do Satellite Galaxies Trace Dark Matter?

We investigate the radial distribution of galaxies within their host dark matter halos by modeling their small-scale clustering, as measured in the Sloan Digital Sky Survey. Specifically, we model the Jiang et al. (2011) measurements of the galaxy two-point correlation function down to very small projected separations (10 < r < 400 kpc/h), in a wide range of luminosity threshold samples (absolute r-band magnitudes of -18 up to -23). We use a halo occupation distribution (HOD) framework with free parameters that specify both the number and spatial distribution of galaxies within their host dark matter halos. We assume that the first galaxy in each halo lives at the halo center and that additional satellite galaxies follow a radial density profile similar to the dark matter Navarro-Frenk-White (NFW) profile, except that the concentration and inner slope are allowed to vary. We find that in low luminosity samples, satellite galaxies have radial profiles that are consistent with NFW. M_r < -20 and brighter satellite galaxies have radial profiles with significantly steeper inner slopes than NFW (we find inner logarithmic slopes ranging from -1.6 to -2.1, as opposed to -1 for NFW). We define a useful metric of concentration, M_(1/10), which is the fraction of satellite galaxies (or mass) that are enclosed within one tenth of the virial radius of a halo. We find that M_(1/10) for low luminosity satellite galaxies agrees with NFW, whereas for luminous galaxies it is 2.5-4 times higher, demonstrating that these galaxies are substantially more centrally concentrated within their dark matter halos than the dark matter itself. Our results therefore suggest that the processes that govern the spatial distribution of galaxies, once they have merged into larger halos, must be luminosity dependent, such that luminous galaxies become poor tracers of the underlying dark matter.Comment: 12 pages, 6 figures, Accepted to Ap

Translational outcomes in a full gene deletion of ubiquitin protein ligase E3A rat model of Angelman syndrome.

Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by developmental delay, impaired communication, motor deficits and ataxia, intellectual disabilities, microcephaly, and seizures. The genetic cause of AS is the loss of expression of UBE3A (ubiquitin protein ligase E6-AP) in the brain, typically due to a deletion of the maternal 15q11-q13 region. Previous studies have been performed using a mouse model with a deletion of a single exon of Ube3a. Since three splice variants of Ube3a exist, this has led to a lack of consistent reports and the theory that perhaps not all mouse studies were assessing the effects of an absence of all functional UBE3A. Herein, we report the generation and functional characterization of a novel model of Angelman syndrome by deleting the entire Ube3a gene in the rat. We validated that this resulted in the first comprehensive gene deletion rodent model. Ultrasonic vocalizations from newborn Ube3am-/p+ were reduced in the maternal inherited deletion group with no observable change in the Ube3am+/p- paternal transmission cohort. We also discovered Ube3am-/p+ exhibited delayed reflex development, motor deficits in rearing and fine motor skills, aberrant social communication, and impaired touchscreen learning and memory in young adults. These behavioral deficits were large in effect size and easily apparent in the larger rodent species. Low social communication was detected using a playback task that is unique to rats. Structural imaging illustrated decreased brain volume in Ube3am-/p+ and a variety of intriguing neuroanatomical phenotypes while Ube3am+/p- did not exhibit altered neuroanatomy. Our report identifies, for the first time, unique AS relevant functional phenotypes and anatomical markers as preclinical outcomes to test various strategies for gene and molecular therapies in AS

Comorbid Depression Among Untreated Illicit Opiate Users : Results From a Multisite Canadian Study

This study aimed to describe patterns of major depression (MDD) in a cohort of untreated illicit opiate users recruited from 5 Canadian urban centres, identify sociodemographic characteristics of opiate users that predict MDD, and determine whether opiate users suffering from depression exhibit different drug use patterns than do participants without depression. Baseline data were collected from 679 untreated opiate users in Vancouver, Edmonton, Toronto, Montreal, and Quebec City. Using the Composite International Diagnostic Interview Short Form for Major Depression, we assessed sociodemographics, drug use, health status, health service use, and depression. We examined depression rates across study sites; logistic regression analyses predicted MDD from demographic information and city. Chi-square analyses were used to compare injection drug use and cocaine or crack use among participants with and without depression. Almost one-half (49.3%) of the sample met the cut-off score for MDD. Being female, white, and living outside Vancouver independently predicted MDD. Opiate users suffering from depression were more likely than users without depression to share injection equipment and paraphernalia and were also more likely to use cocaine (Ps < 0.05). Comorbid depression is common among untreated opiate users across Canada; targeted interventions are needed for this population