Direct Numerical Simulation of Hydrate Dissociation in Homogeneous Porous Media by Applying CFD Method: One Example of CO2 Hydrate

Computational fluid method (CFD) is popular in either large-scale or meso-scale simulations. One example is to establish a new pore-scale (m~μm) model of laboratory-scale sediment samples for estimating the dissociation rate of synthesized CO2 hydrate (CO2H) reported by Jeong. It is assumed that CO2H formed homogeneously in spherical pellets. In the bulk flow, concentration and temperature of liquid CO2 in water flow was analyzed by CFD method under high-pressure state. Finite volume method (FVM) were applied in a face-centered packing in unstructured mesh. At the surface of hydrate, a dissociation model has been employed. Surface mass and heat transfer between hydrate and water are both visualized. The initial temperature 253.15K of CO2H pellets dissociated due to ambient warm water flow of 276.15 and 282.15K and fugacity variation, ex. 2.01 and 1.23 MPa. Three tentative cases with porosity 74, 66, and 49% are individually simulated in this study. In the calculation, periodic conditions are imposed at each surface of packing. Numerical results of this work show good agreement with Nihous’ model. Kinetic modeling by using 3D unstructured mesh and CFD scheme seems a simple tool, and could be easily extended to determine complex phenomena coupled with momentum, mass and heat transfer in the sediment samples

Applying Vector Boson Fusion Topologies to Search for Supersymmetric and Higgs Portal Dark Matter at the LHC

This work presents two searches for dark matter at the Large Hadron Collider (LHC). The first is focused on decays of the supersymmetric partner of the top quark, the stop quark (t). By exploiting vector boson fusion (VBF) topologies, the analysis shows a top squark with mass of 300 GeV and integrated luminosity of 300 fb ˉ¹ can be probed at 5σ significance with no systematic uncertainty. The second search is a study of Higgs portal dark matter (HPDM). In order to study HPDM, we consider two boosted channels. The first is a study of vector boson fusion production. Here we show the differences between the ET distribution for HPDM and wino dark matter. We also show the significance as a function of DM mass. The second channel for HPDM is Z + H production of DM. In this case, we are interested in trying to differentate between fermionic, scalar, and vector DM. We show kinematic distributions for these three cases. Additionally, we consider the influence of the Higgs width on these kinematic distributions for the fermionic case

Comparing Bulk Aerosol Profiles in the Mixed Layer in Coastal Los Angeles and the Inland Empire

Characteristic westerly sea breeze carries air over the Los Angeles Basin in Southern California to the Inland Empire approximately 50 miles inland, directly impacting air quality in both of these two highly polluted regions. As particles play a critical role in air quality and human health, this study compares the bulk aerosol profiles of the Los Angeles pollution source and Inland Empire receptor regions during the 2013 and 2014 NASA Student Airborne Research Program (SARP) campaigns onboard the NASA DC-8 airborne laboratory. The source and receptor regions were characterized by a series of missed approaches at the Los Angeles International Airport, Long Beach Airport, and Los Alamitos Army Airfield (coastal sources) as well as the Ontario International Airport, San Bernardino International Airport, and March Air Reserve Base (inland receptors). The aerosol populations in each region were compared, and the changes evolved were analyzed alongside volatile organic compound (VOC) concentrations from Whole Air Samples. Particle size distributions were collected using a Droplet Measurement Technologies Ultra High Sensitivity Aerosol Spectrometer (DMT-UHSAS). Aerosol concentration, mass, and mode diameter increased significantly between coastal pollution source and inland pollution receptor regions in all cases, along with an increase in mode diameter. The observed changes cannot be accounted for by aerosol aging over the Los Angeles basin alone, suggesting new particle emission/formation over this region could be a dominating factor in the changes. Positive correlations between particle increases at receptor sites and anthropogenic VOC tracers will be discussed

Top Squark Searches Using Dilepton Invariant Mass Distributions and Bino-Higgsino Dark Matter at the LHC

Pair production of light top squarks at the 8-TeV LHC can be used to probe the gaugino-Higgsino sector of the Minimal Supersymmetric Standard Model. The case where the lightest neutralino is a mixture of Bino and Higgsino, satisfying the thermal dark matter relic density, is investigated. In such a scenario, the lightest top squark decays mostly into $(i)$ a top quark plus the second or third lightest neutralino, and $(ii)$ a bottom quark plus the lightest chargino, instead of a decay scenario of the lightest top squark into a top quark and the lightest neutralino. Final states with $\geq 2$ jets, dileptons, and missing energy are expected in a subsequent decay of the second or third lightest neutralinos into the lightest neutralino via an intermediate slepton ("light sleptons" case) or $Z$ boson ("heavy sleptons" case). The opposite-sign same flavor dilepton mass distribution after subtracting the opposite-sign different flavor distribution shows a clear edge in the case of light sleptons. The significance for discovering such a scenario is calculated with optimized cuts in both light and heavy sleptons cases.Comment: 6 pages, 3 figures. Version accepted in Phys. Rev.

A Review of Research on Aging Families: Emerging Issues

Against the background of the demographic shifts of population aging, increased immigration, and growing ethno‐cultural diversity in Canada, it is important that we gain a better understanding of the needs of aging families. To date, family gerontologists have begun producing research on aging families to better understand how their needs can be met. In order to assess the state of the literature on aging families, we conducted a literature search (2009‐ 2014) of eleven top, peer‐reviewed journals. This literature was then assessed, revealing five prevalent themes: (1) structural diversity in aging families, (2) family relationships in later life, (3) caregiving and intergenerational transfers, (4) living arrangements of aging families, and (5) partnerships in later life. This article synthesizes the research of each theme and each of their subsequent sub‐themes. Lastly, the article concludes with some suggestions for future directions in research which were revealed through the literature review

Probing Compressed Bottom Squarks with Boosted Jets and Shape Analysis

A feasibility study is presented for the search of the lightest bottom squark (sbottom) in a compressed scenario, where its mass difference from the lightest neutralino is 5 GeV. Two separate studies are performed: $(1)$ final state containing two VBF-like tagging jets, missing transverse energy, and zero or one $b$-tagged jet; and $(2)$ final state consisting of initial state radiation (ISR) jet, missing transverse energy, and at least one $b$-tagged jet. An analysis of the shape of the missing transverse energy distribution for signal and background is performed in each case, leading to significant improvement over a cut and count analysis, especially after incorporating the consideration of systematics and pileup. The shape analysis in the VBF-like tagging jet study leads to a $3\sigma$ exclusion potential of sbottoms with mass up to $530 \, (462)$ GeV for an integrated luminosity of $300$ fb$^{-1}$ at 14 TeV, with $5\%$ systematics and PU $= 0 \, (50)$.Comment: 5 pages, 4 figures. Discussions and references updated, reach for PU=50 case give

Adaptive Control for Estimating Insulation Resistance of High- Voltage Battery System in Electric Vehicles

To ensure electrical safety and reliability in electric vehicles equipped with a high-voltage battery pack, an insulation monitoring circuit is indispensable to continuously monitor the insulation resistance during charging or driving. Existing methods such as injecting specific signals into the monitoring circuit and earth help to extract the resistance value from the voltage waveform. However, parasitic or stray capacitances in the monitoring circuit, which might introduce higher order dynamics into the waveform, are ignored. To avoid estimation error, the insulation resistance must be known in advance to carry out parameter calibration. In this chapter, one parasitic capacitance is applied in the circuit model and a new adaptive algorithm based on Lyapunov stability is employed to estimate the insulation resistance. This new online monitoring method and circuit are verified through simulation and experimentation, respectively. The results demonstrate that the proposed method can quickly react and track variations of insulation resistance on both positive and negative direct current (DC) lines

Reused Lithium-Ion Battery Applied in Water Treatment Plants

For stabilizing renewable energies and shaving peak power at noon, both the energy consumption and potential renewable energies in Dihua waste water treatment plant (WWTP) in Taiwan are analyzed. Under the consideration of environment, cost, and performance, automotive reused lithium-ion battery (RLIB) is employed. Two typical automotive lithium-ion batteries are used in this study after the selection of suitable battery cells. In particular, one simple, converterless energy management system (EMS) is developed and integrated in new RLIB packs. The control strategy between RLIB and an additional physical battery is adjusted by simulation. An online estimation of RLIB’s internal resistance and open-circuit voltage monitoring scheme is applied in EMS to ensure the safety of RLIB. The bench test and rough economical estimation reveal that EMS shows great potential in elongating life cycle and possibly benefits from feed-in tariff and peak shift of electricity charges

Probing Compressed Top Squarks at the LHC at 14 TeV

A feasibility study is presented for the search of the lightest top squark in a compressed scenario, where its mass is approximately equal to the sum of the masses of the top quark and the lightest neutralino. The study is performed in the final state of two b-jets, one lepton, large missing energy, and two high-$E_{\rm T}$ jets with large separation in pseudo-rapidity, in opposite hemispheres, and with large dijet mass. The LHC could discover compressed top squarks with mass up to approximately 340 GeV (390 GeV) with an integrated luminosity of 1000 ifb (3000 ifb).Comment: Version updated with major changes: (a) 3-body stop decay (to b+W+n1) analyzed for first time (b) systematics calculation and discussion significantly upgraded (c) new kinematic and mass reach plots for the 3-body decay scenario added (d) discussions clarified throughou