Nonlinear Loss Model In Absorptive-Type Ferrite Frequency-Selective Limiters

Absorptive-type ferrite-based frequency-selective limiters (FSLs) utilize nonlinear (NL) phenomena in magnetized ferrites to provide real-time analog signal processing of RF/microwave electromagnetic (EM) signals. There are no commercially available modeling tools that simulate these interactions, and the development and optimization of FSLs are largely done experimentally. FSL modeling and design is complicated by NL, multiscale, and Multiphysics nature of operation. In this article, an NL loss model in a ferrite is proposed and implemented in an efficient numerical algorithm. The equivalent linear magnetic loss tangent is represented in a closed form. A full-wave numerical EM model with high-fidelity meshing is set up so that material properties are assigned to each mesh element and are iteratively adjusted depending on the local magnetic field. The numerical model is sliced along the EM wave propagation, and an NL eigenvalue is obtained for each slice as a function of frequency, power, and external magnetic bias field and stored in lookup tables. The slices are cascaded, and power attenuation is calculated with loss changing along the wave path according to the lookup tables. The resulting data are processed to be suitable for equivalent circuit models. Numerical results for coplanar waveguide FSL are validated by measurements. The proposed modeling approach is useful for engineering FSL devices

Adaptive Interference Mitigation Using Frequency-Selective Limiters Over GPS Band For Automotive Applications

In this work, we address the challenges associated with the necessity to protect Global Positioning system (GPS) receivers from various types of electromagnetic interference (EMI) generated by internal or external sources. We have developed a compact, lightweight, and passive frequency selective limiter (FSL) technology that automatically and adaptively protects vulnerable input circuits of a GPS receiver from unwanted emissions and prevents a GPS receiver from going into saturation. This technology is based on using magnetostatic surface waves in a magnetically biased ferrite film. The nonlinear processes in ferrite films enable discrimination of signals based on their power levels. In these devices, the frequency-selective transmission response adjusts rapidly and automatically, in real time, such that no portion of the output spectrum exceeds a designated power threshold. FSLs are capable of mitigating multiple interfering signals without prior knowledge of the timing or the frequency content of the interferers. A few examples of FSL design and measured characteristics are provided for GPS L1 band

Gait speed, body composition, and dementia. The EPIDOS-Toulouse cohort

BACKGROUND: Slow gait speed (GS) predicts dementia, but this association might be mediated by body composition parameters like total fat mass (TFM) or total lean mass (TLM). The aim of the study was to evaluate whether GS, TLM, and TFM were associated factors with an increased risk for subsequent dementia in community-dwelling older women.METHODS: A case-control study was nested in the EPIDemiologie de l\u27OSteoporose cohort. GS (at usual pace more than 6 m), TLM, and TFM (assessed by dual energy x-ray absorptiometry) were measured at baseline. Cognitive performance was evaluated at baseline and at 7 years of follow-up. The presence of dementia was assured by two blinded memory experts based on best practice and validated criteria. Multivariate logistic regression models assessed the association of GS, TLM, and TFM with dementia risk. RESULTS: Of the initial 1,462 women, 75 years old and older, 647 (43.4%) were cognitively intact at baseline and had a full cognitive assessment at 7 years (145 of them developed dementia). Controlled for covariates (demographics, physical activity, self-reported disabilities, and comorbidities), GS was an independent associated factor for subsequent dementia as a continuous variable (odds ratio [OR] 2.28, 95% CI: 1.32-3.94) and as a categorized variable (OR 2.38, 95% CI: 1.28-4.43 highest vs lowest quartile). Neither interaction with GS nor a statistically significant association with dementia risk was found for TLM and TFM. CONCLUSIONS: GS was an independent associated factor for subsequent dementia not mediated by TLM or TFM

Dietary Vitamin D Intake and Muscle Mass in Older Women. Results from a Cross-Sectional Analysis of the Epidos Study

Objectives: Vitamin D intake may prevent physical performance decline through prevention of muscle mass loss. Our objective was to determine whether low dietary intakes were associated with low muscle mass (MM). Design and participants: Cross-sectional analysis of 1989 community-dwelling women (mean age 80.5 +/- 3.8years) from the EPIDemiologie de l\u27OSteoporose (EPIDOS) study were assessed at baseline. Measurements: Low intakes of vitamin D (<70 mu g/week) were estimated from the weekly dietary vitamin D intakes (self-administered food frequency questionnaire). Low MM was defined according to the appendicular skeletal muscle mass index assessed using Dual Energy X-ray Absorptiometry, divided by square height of less than 5.45 kg/m(2). Usual gait speed defined physical performance. Age, sun exposure, co-morbidities, education level, living arrangements, recreational physical activity, dietary protein and calcium intakes, bone mineral density, handgrip strength, and body mass index were considered as potential confounders. Multivariate logistic regression analyses assessed the association between low vitamin D intakes and low MM. Results: Two-hundred and nine (10.5%) women with low MM were compared to 1,780 women with normal MM. In final model, obesity/overweight (Adjusted Odds Ratios, aOR=0.09; 95%CI [0.05-0.17]), malnutrition (aOR=3.90; 95%CI [2.74-5.54]) and low handgrip strength (aOR=2.33; 95%CI [1.44-3.77]; p<0.001) were statistically associated with a low MM status. Conclusion: No association with low MM has been reported regarding low dietary intakes of vitamin D

Sarcopenia and cognitive impairment in elderly women: results from the EPIDOS cohort

BACKGROUND: common pathophysiological pathways are shared between age-related body composition changes and cognitive impairment. OBJECTIVE: evaluate whether current operative sarcopenia definitions are associated with cognition in community-dwelling older women. DESIGN: cross-sectional analyses. SUBJECTS: a total of 3,025 women aged 75 years and older. MEASUREMENTS: body composition (assessed by dual energy X-ray absorptiometry) and cognition (measured by short portable mental status questionnaire) were obtained in all participants. Multivariate logistic regression models assessed the association of six operative definitions of sarcopenia with cognitive impairment. Gait speed (GS, measured over a 6-meter track at usual pace) and handgrip strength (HG, measured by a hand-held dynamometer) were considered additional factors of interest. RESULTS: a total of 492 (16.3%) women were cognitively impaired. The prevalence of sarcopenia ranged from 3.3 to 18.8%. No sarcopenia definition was associated with cognitive impairment after controlling for potential confounders. To proof consistency, the analyses were performed using GS and HG, two well-established predictors of cognitive impairment. Low GS [odds ratio (OR) 2.42, 95% confidence interval (CI) 1.72-3.40] and low HG (OR: 1.81, 95% CI: 1.33-2.46) were associated with cognitive impairment. CONCLUSION: no significant association was evidenced between different operative sarcopenia definitions and cognitive impairment. The study suggests that the association between physical performance and cognitive impairment in not mediated by sarcopenia

Preliminary implementation for the new SPIRAL2 project control system

International audienceThe Spiral2 project consists of a new facility to provide high intensity rare ions beams. It is based on a primary beam driver accelerator (RFQ followed by a superconducting linac) and a rare ion production process delivering the beam either to a low energy experimental area or to the existing Ganil facility. From October this year, one ion source coupled with a first beam line section will be in test; then, the injector (ion and deuteron sources, RFQ) will be tested by the end of 2010 so the whole accelerator should be commissioned by the end of 2011; the first exotic beams being planned one year later. The accelerator control system design results from the collaboration between several institutes and Epics has been chosen as the basic framework. The paper therefore presents the main choices: MVME5500 CPUs, VME I/O boards, VxWorks, Siemens PLCs, Modbus field buses, EDM screens and Java applications, Linux PCs, use of a LabView/Epics gateway... Specific topics are the evaluation of the XAL environment, an Epics design to address the power supplies, an emittance measurement system, the development of a beam profiler interface and the investigation for a triggered acquisition system

The SPIRAL2 control system progress towards the commissioning phase

MOCOAAB03, http://accelconf.web.cern.ch/AccelConf/ICALEPCS2013/papers/mocoaab03.pdfInternational audienceThe commissioning of the first phase of the Spiral2 Radioactive Ion Beams facility at Ganil will soon start, so requiring the control system components to be delivered in time. Yet, parts of the system were validated during preliminary tests performed with ions and deuterons beams at low energy. The control system development results from the collaboration between Ganil, CEA-IRFU, CNRS-IPHC laboratories, using appropriate tools and approach. Based on Epics, the control system follows a classical architecture. At the lowest level, Modbus/TCP protocol is considered as a field bus. Then, equipment are handled by IOCs (soft or VME/VxWorks) with a software standardized interface between IOCs and clients applications on top. This last upper layer consists of Epics standard tools, CSS/BOY user interfaces within the socalled CSSop Spiral2 context suited for operation and, for machine tunings, high level applications implemented by Java programs developed within a Spiral2 framework derived from the open-Xal one. Databases are used for equipment data and alarms archiving, to configure equipment and to manage the machine lattice and beam settings. A global overview of the system is therefore here proposed

Open XAL status Report 2015

Open XAL is an accelerator physics software platform developed in collaboration among several facilities around the world. The Open XAL collaboration was formed in 2010 to port, improve and extend the successful XAL platform used at the Spallation Neutron Source for use in the broader accelerator community and to establish it as the standard platform for accelerator physics software. The site-independent core is complete, active applications have been ported, and now we are in the process of verification and transitioning to using Open XAL in production. This paper will present the current status and a roadmap for this project

OPEN XAL Status Report 2015

MOPW1050International audienceOpen XAL is an accelerator physics software platformdeveloped in collaboration among several facilitiesaround the world. The Open XAL collaboration wasformed in 2010 to port, improve and extend the successfulXAL platform used at the Spallation Neutron Source foruse in the broader accelerator community and to establishit as the standard platform for accelerator physicssoftware. The site-independent core is complete, activeapplications have been ported, and now we are in theprocess of verification and transitioning to using OpenXAL in production. This paper will present the currentstatus and a roadmap for this project