Absolute Magnitude Calibration for Giants based on the Colour-Magnitude Diagrams of Galactic Clusters. II-Calibration with SDSS

We present an absolute magnitude calibration for red giants with the colour magnitude diagrams of six Galactic clusters with different metallicities i.e. M92, M13, M3, M71, NGC 6791 and NGC 2158. The combination of the absolute magnitudes of the red giant sequences with the corresponding metallicities provides calibration for absolute magnitude estimation for red giants for a given $(g-r)_{0}$ colour. The calibration is defined in the colour interval 0.45 $\leq(g-r)_{0}\leq$ 1.30 mag and it covers the metallicity interval $-2.15\leq \lbrack Fe/H \rbrack \leq$ +0.37 dex. The absolute magnitude residuals obtained by the application of the procedure to another set of Galactic clusters lie in the interval $-0.28< \Delta M \leq +0.43$ mag. However, the range of 94% of the residuals is shorter, $-0.1<\Delta M \leq+0.4$ mag. The mean and the standard deviation of (all) residuals are 0.169 and 0.140 mag, respectively. The derived relations are applicable to stars older than 2 Gyr, the age of the youngest calibrating cluster.Comment: 12 pages, including 5 figures and 10 tables, accepted for publication in PASA. arXiv admin note: substantial text overlap with arXiv:1204.429

Shear-dependent apparent slip on hydrophobic surfaces: The Mattress Model

Recent experiments (Zhu & Granick (2001) Phys. Rev. Lett. 87 096105) have measured a large shear dependent fluid slip at partially wetting fluid-solid surfaces. We present a simple model for such slip, motivated by the recent observations of nanobubbles on hydrophobic surfaces. The model considers the dynamic response of bubbles to change in hydrodynamic pressure due to the oscillation of a solid surface. Both the compression and diffusion of gas in the bubbles decrease the force on the oscillating surface by a ``leaking mattress'' effect, thereby creating an apparent shear-dependent slip. With bubbles similar to those observed by atomic force microscopy to date, the model is found to lead to force decreases consistent with the experimental measurements of Zhu & Granick

Effects of circular measures on scarce metals in complex products – Case studies of electrical and electronic equipment

Circular measures such as long-life designs, reuse, repair and recycling have been suggested for prolonging scarce metal life cycles and reducing the dependence on primary resources. This paper explores to what extent circular measures could mitigate metals scarcity when adopted to complex products. Based on three real cases, the effect of extending the use of laptops, smartphones and LED systems before recycling are assessed for between 7 and 15 scarce metals using material flow analysis. As expected, benefits can be gained from such extensions, but, importantly, differ substantially between metals since they occur in various components with various service lifetimes and functional recycling rates vary. Notably, risks of flipping the ranking in favor of short use before recycling are identified: if service lifetimes are short, designs are metal-intensive or if metal contents differ between products. Furthermore, regardless of measure, sizable and varying losses of each metal from functional use occur since all products are not collected for recycling and all metals are not functionally recycled. Thus, neither use extension measures nor recycling can alone nor in combination radically mitigate metals scarcity and criticality currently. Overall, it is a challenge to target the multitude of scarce and critical metals applied in complex products through circular measures. Careful analysis beyond simplified guidelines such as \uf6R frameworks” are recommended. As the importance of scarce metals availability and the attention to the circular economy are expected to continue, these insights may be used for avoiding efforts with unclear or minor benefits or even drawbacks

Absolute Magnitude Calibration for Red Giants based on the Colour-Magnitude Diagrams of Galactic Clusters. III-Calibration with 2MASS

We present two absolute magnitude calibrations, $M_{J}$ and $M_{K_s}$, for red giants with the colour magnitude diagrams of five Galactic clusters with different metallicities i.e. M92, M13, M71, M67, and NGC 6791. The combination of the absolute magnitudes of the red giant sequences with the corresponding metallicities provides calibration for absolute magnitude estimation for red giants for a given colour. The calibrations for $M_{J}$ and $M_{K_s}$ are defined in the colour intervals $1.3\leq(V-J)_{0}\leq2.8$ and $1.75 \leq (V-K_{s})_{0}\leq 3.80$ mag, respectively, and they cover the metallicity interval $-2.15 \leq \lbrack Fe/H \rbrack \leq +0.37$ dex. The absolute magnitude residuals obtained by the application of the procedure to another set of Galactic clusters lie in the intervals $-0.08<\Delta M_{J}\leq +0.34$ and $-0.10< \Delta M_{K_s}\leq +0.27$ mag for $M_{J}$ and $M_{K_s}$, respectively. The means and standard deviations of the residuals are $= 0.137$ and $\sigma_{M_J}=0.080$, and $=0.109$ and $\sigma_{M_{K_{s}}}=0.123$ mag. The derived relations are applicable to stars older than 4 Gyr, the age of the youngest calibrating cluster.Comment: 20 pages, including 8 figures and 22 tables, accepted for publication in PASA. arXiv admin note: substantial text overlap with arXiv:1206.275

Optimizing single-photon-source heralding efficiency at 1550 nm using periodically poled lithium niobate

We explore the feasibility of using high conversion-efficiency periodically-poled crystals to produce photon pairs for photon-counting detector calibrations at 1550 nm. The goal is the development of an appropriate parametric down-conversion (PDC) source at telecom wavelengths meeting the requirements of high-efficiency pair production and collection in single spectral and spatial modes (single-mode fibers). We propose a protocol to optimize the photon collection, noise levels and the uncertainty evaluation. This study ties together the results of our efforts to model the single-mode heralding efficiency of a two-photon PDC source and to estimate the heralding uncertainty of such a source.Comment: 14 pages, 2 tables and 3 figures, final version accepted by Metrologi

Optimal focusing for maximal collection of entangled narrow-band photon pairs into single-mode fibers

We present a theoretical and experimental investigation of the emission characteristics and the flux of photon pairs generated by spontaneous parametric downconversion in quasi-phase matched bulk crystals for the use in quantum communication sources. We show that, by careful design, one can attain well defined modes close to the fundamental mode of optical fibers and obtain high coupling efficiencies also for bulk crystals, these being more easily aligned than crystal waveguides. We distinguish between singles coupling, conditional coincidence, and pair coupling, and show how each of these parameters can be maximized by varying the focusing of the pump mode and the fiber-matched modes using standard optical elements. Specifically we analyze a periodically poled KTP-crystal pumped by a 532 nm laser creating photon pairs at 810 nm and 1550 nm. Numerical calculations lead to coupling efficiencies above 94% at optimal focusing, which is found by the geometrical relation L/z_R to be ~ 1 to 2 for the pump mode and ~ 2 to 3 for the fiber-modes, where L is the crystal length and z_R is the Rayleigh-range of the mode-profile. These results are independent on L. By showing that the single-mode bandwidth decreases as 1/L, we can therefore design the source to produce and couple narrow bandwidth photon pairs well into the fibers. Smaller bandwidth means both less chromatic dispersion for long propagation distances in fibers, and that telecom Bragg gratings can be utilized to compensate for broadened photon packets--a vital problem for time-multiplexed qubits. Longer crystals also yield an increase in fiber photon flux proportional to sqrt{L}, and so, assuming correct focusing, we can only see advantages using long crystals.Comment: 19 pages, 15 figures, ReVTeX4, minor revisio

Theory and experiment of entanglement in a quasi-phase-matched two-crystal source

We report new results regarding a source of polarization entangled photon-pairs created by the process of spontaneous parametric downconversion in two orthogonally oriented, periodically poled, bulk KTiOPO4 crystals (PPKTP). The source emits light colinearly at the non-degenerate wavelengths of 810 nm and 1550 nm, and is optimized for single-mode optical fiber collection and long-distance quantum communication. The configuration favors long crystals, which promote a high photon-pair production rate at a narrow bandwidth, together with a high pair-probability in fibers. The quality of entanglement is limited by chromatic dispersion, which we analyze by determining the output state. We find that such a decoherence effect is strongly material dependent, providing for long crystals an upper bound on the visibility of the coincidence fringes of 41% for KTiOPO4, and zero for LiNbO3. The best obtained raw visibility, when canceling decoherence with an extra piece of crystal, was 91 \pm 0.2%, including background counts. We confirm by a violation of the CHSH-inequality (S = 2.679 \pm 0.004 at 55 s^{-1/2} standard deviations) and by complete quantum state tomography that the fibers carry high-quality entangled pairs at a maximum rate of 55 x 10^3 s^{-1}THz^{-1}mW^{-1}.Comment: 12 pages, 10 figures, REVTeX

Explore - Exploring the opportunities for advancing vehicle recycling industrialization

After almost four years of research, it is time to summarise the findings of the Explore project. Involving actors from across the vehicle value chain, it has aimed to increase dialogue and communication, built knowledge regarding the composition of vehicles and pinpointed barriers and opportunities to improve circular flows of vehicle materials in the future.The project\u27s goal is to find ways to strengthen Swedish automotive recycling industry’s role in a more circular economy and create close cooperation between manufacturing and recycling industries. Against this background, the project has the following objectives:* Analyze future vehicle fleet\u27s material content and its implication for recycling system adaptation.* Adopt and adapt manufacturing planning and control theories and practices to develop a more efficient vehicle dismantling.* Analyze and propose solutions for more efficient reverse logistics in vehicle recycling.* Identify political and industrial action that can support the development of Swedish vehicle recycling.* Identify technical solutions for disassembly, sorting and recycling of future vehicles.The project was carried out through six individual work packages related to different parts of the vehicle value chain

Challenges of recycling multiple scarce metals: The case of Swedish ELV and WEEE recycling

Cars and electronic products are characterised by high metal complexity. Meanwhile, recycling industries are not fully aligned with this complexity, leading to losses of unique scarce metal resources. By utilising the technological innovation system framework we identify, and discuss implications of, factors that impact on recycling of some precious (gold, palladium, silver) and minor metals (gallium, tantalum) in printed circuit boards (PCBs) present in Swedish end-of-life cars (ELVs) and waste electrical and electronic equipment (WEEE). We conclude that while precious metals from WEEE PCBs are currently recycled, recycling precious metals from ELV PCBs will likely remain a challenge in the near-term due to recycling being blocked by the material composition of ELV waste, design of waste legislation, and by accumulated capabilities and business models in current recycling industries. However, some of these blocking factors are open to direct influence from national policymakers or industry actors and may thus be alleviated more easily. In contrast, recycling minor metals from ELV or WEEE PCBs will likely remain challenging also in the long-term due to a larger set of blocking factors. Alleviating these may require a substantial portfolio of metal-specific policies at national and supra national levels supporting the build-up of entirely new recycling value chains

A scalable life cycle inventory of an automotive power electronic inverter unit—part I: design and composition

Purpose: A scalable life cycle inventory (LCI) model, which provides mass composition and manufacturing data for a power electronic inverter unit intended for controlling electric vehicle propulsion motors, was developed. The purpose is to fill existing data gaps for life cycle assessment (LCA) of electric vehicles. The model comprises new and easy-to-use data with sufficient level of detail to enable proper component scaling and more in-depth analysis of inverter units. It represents a stand-alone three-phase inverter with insulated gate bipolar transistors (IGBTs), typical in electric vehicles. This article (part I) explains the modeling of the inverter design including the principles for scaling, exemplifies results, and evaluates the models’ mass estimations.Methods: Data for the design of power electronic inverter units was compiled from material content declarations, textbooks, technology benchmarking literature, experts in industry, and product descriptions. Detailed technical documentation for two electrically and electronically complete inverter units were used as a baseline and were supplemented with data for casings, connectors, and bus bars suitable for automotive applications. Data, theory, and design rules were combined to establish a complete model, which calculates the mass of all subparts from an input of nominal power and DC system voltage. The validity of the mass estimates was evaluated through comparison with data for real automotive inverter units.Results and discussion: The results of the LCI model exemplifies how the composition of the inverter unit varies within the model range of 20–200 kW and 250–700 V, from small passenger car applications up to distribution trucks or city buses. The models’ mass estimations deviate up to 14% from the specified mass for ten examples of real inverter units. Despite the many challenges of creating a generic model of a vehicle powertrain part, including expected variability in design, all results of the model validation fall within the targeted goal for accuracy.Conclusions: The LCI model combines different principles for the scaling of subparts into one model that capture important design implications of different power demands and voltage ratings. The model can be used for a generic estimation of the mass and material composition of a power electronic inverter unit controlling electric propulsion motors, for LCA, when specific data is lacking