16,244 research outputs found

    Effect of venting range hood flow rate on size-resolved ultrafine particle concentrations from gas stove cooking

    Get PDF
    Cooking is the main source of ultrafine particles (UFP) in homes. This study investigated the effect of venting range hood flow rate on size-resolved UFP concentrations from gas stove cooking. The same cooking protocol was conducted 60 times using three venting range hoods operated at six flow rates in twin research houses. Size-resolved particle (10–420 nm) concentrations were monitored using a NanoScan scanning mobility particle sizer (SMPS) from 15 min before cooking to 3 h after the cooking had stopped. Cooking increased the background total UFP number concentrations to 1.3 × 103 particles/cm3 on average, with a mean exposure-relevant source strength of 1.8 × 1012 particles/min. Total particle peak reductions ranged from 25% at the lowest fan flow rate of 36 L/s to 98% at the highest rate of 146 L/s. During the operation of a venting range hood, particle removal by deposition was less significant compared to the increasing air exchange rate driven by exhaust ventilation. Exposure to total particles due to cooking varied from 0.9 to 5.8 × 104 particles/cm3·h, 3 h after cooking ended. Compared to the 36 L/s range hood, higher flow rates of 120 and 146 L/s reduced the first-hour post-cooking exposure by 76% and 85%, respectively. © 2018 Crown Copyright. Published with license by Taylor & Francis Group, LLC

    How can a 22-pole ion trap exhibit 10 local minima in the effective potential?

    Full text link
    The column density distribution of trapped OH^- ions in a 22-pole ion trap is measured for different trap parameters. The density is obtained from position-dependent photodetachment rate measurements. Overall, agreement is found with the effective potential of an ideal 22-pole. However, in addition we observe 10 distinct minima in the trapping potential, which indicate a breaking of the 22-fold symmetry. Numerical simulations show that a displacement of a subset of the radiofrequency electrodes can serve as an explanation for this symmetry breaking

    Searching for new physics in bssdˉb\to s s \bar d decays

    Full text link
    For any new physics possibly emerging in the future B experiments, the problem is how to extract the signals from the SM background. We consider the decay bssdˉb\to s s\bar d which is very small in the SM. In the MSSM this decay is possibly accessible in the future experiments. In the supersymmetric models with R-parity violating couplings, this channel is not strictly constrained, thus being useful in obtaining bounds on the lepton-number violating couplings. A typical candidate for the suggested search is the BKKπ+B^-\to K^-K^-\pi^+ mode.Comment: 9 pages, one figure, late

    Magnetic friction due to vortex fluctuation

    Full text link
    We use Monte Carlo and molecular dynamics simulation to study a magnetic tip-sample interaction. Our interest is to understand the mechanism of heat dissipation when the forces involved in the system are magnetic in essence. We consider a magnetic crystalline substrate composed of several layers interacting magnetically with a tip. The set is put thermally in equilibrium at temperature T by using a numerical Monte Carlo technique. By using that configuration we study its dynamical evolution by integrating numerically the equations of motion. Our results suggests that the heat dissipation in this system is closed related to the appearing of vortices in the sample.Comment: 6 pages, 41 figure

    Progress on the Low-Latency Inspiral Gravitational Wave Detection algorithm known as SPIIR

    No full text
    Low-latency event triggers to signify the presence of gravitational waves from coalescing binaries will be required to make prompt electromagnetic follow-up observations of electromagnetic counterparts. We present the recent progress made on implementing the time-domain low-latency detection algorithm known as summed parallel infinite impulse response (SPIIR) filtering into a real gravitational wave search pipeline
    corecore