393 research outputs found

    Final Step to Green En Masse Financially

    Get PDF
    We make seven direct intra-brand comparisons between legacy carmakers’ electric vehicle (EV) and gas-powered vehicle who achieved top ten most-efficient electric vehicles in America. We find six out of the seven EVs will be able to breakeven the higher price relative to their gas counterparts within reasonable gas price range, electricity charge range, and federal government tax credit for buying EVs. We further find that federal government tax credit is the most effective policy tool that will induce new car buyers to choose EVs over comparable same-brand gas vehicle though other green initiatives such as solar panels on owner’s roof tops and below-market-interest-rate (BMIR) loans are effective as well

    Shock Acceleration of Solar Energetic Protons: The First 10 Minutes

    Get PDF
    Proton acceleration at a parallel coronal shock is modeled with self-consistent Alfven wave excitation and shock transmission. 18 - 50 keV seed protons at 0.1% of plasma proton density are accelerated in 10 minutes to a power-law intensity spectrum rolling over at 300 MeV by a 2500km s-1 shock traveling outward from 3.5 solar radius, for typical coronal conditions and low ambient wave intensities. Interaction of high-energy protons of large pitch-angles with Alfven waves amplified by low-energy protons of small pitch angles is key to rapid acceleration. Shock acceleration is not significantly retarded by sunward streaming protons interacting with downstream waves. There is no significant second-order Fermi acceleration

    How To Create Cash Flows That Give A Priori IRRs?

    Get PDF
    We illustrate algebraically the way to numerically derive the cash flows of an investment project yielding a set of desired IRRs. This is significant given the dearth of practice questions with the appropriate cash flow numbers, and their corresponding sign, in widely adopted Finance textbooks that will allow students to find multiple IRRs as learning exercises. The note serves to fill that void by allowing the readers to change the IRR inputs in an Excel spreadsheet and have the corresponding cash flows output ready for an assignment. Instructors can use the Excel codes to create different cash flows that yield multiple IRRs with ease so that students in the same class or those in different semesters need not be given the same set of cash flows where plagiarism could compromise the learning process

    Ion Anisotropy and High-Energy Variability of Large Solar Particle Events: A Comparative Study

    Get PDF
    We have made comparative studies of ion anisotropy and high-energy variability of solar energetic particle (SEP) events previously examined by the Solar, Heliospheric, and Interplanetary Environment (SHINE) Workshop campaign. We have found distinctly different characteristics of SEPs between two large "gradual" events having very similar solar progenitors (the 2002 April 21 and August 24 events). Since the scattering centers of SEPs are approximately frozen in the solar wind, we emphasize work in the solar-wind frame where SEPs tend to be isotropized, and small anisotropies are easier to detect. While in the August event no streaming reversal occurred, in the April event the field-aligned anisotropy of all heavy ions showed sign of streaming reversal. The difference in streaming reversal was consistent with the difference in the presence of the outer reflecting boundary. In the April event the magnetic mirror, which was located behind the interplanetary shock driven by the preceding coronal mass ejection (CME), could block the stream of SEPs, while in the August event SEPs escaped freely because of the absence of nearby boundary. The magnetic mirror was formed at the bottleneck of magnetic field lines draped around a flank of the preceding CME. In the previous SHINE event analysis the contrasting event durations and Fe/O ratios of the both events were explained as the interplay between shock geometry and seed population. Our new findings, however, indicate that event duration and time as well as spectral variation are also affected by the presence of a nearby reflecting boundary

    Natural disasters and tourism-led growth economic growth a case study of Fiji : 1980-2014

    Get PDF
    Although tourism in recent years has emerged as engine of growth in Fiji, the uncertainties associated with the disastrous impact of tropical cyclones have been causing greater anxieties in recent times with increase in the number of cyclones each year hitting the South Pacific region. This paper focuses on the effects of cyclones on tourism and growth in Fiji. The data on damages inflicted by past annual cyclones are scanty. The quantitative estimates are based more on anecdotal evidence than on systematic assessments. Given these constraints, the paper attempts to undertake an empirical study through employing a bi-nary variable for cyclone, along with conventional variables.peer-reviewe

    Source Regions of the Interplanetary Magnetic Field and Variability in Heavy-Ion Elemental Composition in Gradual Solar Energetic Particle Events

    Get PDF
    Gradual solar energetic particle (SEP) events are those in which ions are accelerated to their observed energies by interactions with a shock driven by a fast coronal mass-ejection (CME). Previous studies have shown that much of the observed event-to-event variability can be understood in terms of shock speed and evolution in the shock-normal angle. But an equally important factor, particularly for the elemental composition, is the origin of the suprathermal seed particles upon which the shock acts. To tackle this issue, we (1) use observed solar-wind speed, magnetograms, and the PFSS model to map the Sun-L1 interplanetary magnetic field (IMF) line back to its source region on the Sun at the time of the SEP observations; and (2) then look for correlation between SEP composition (as measured by Wind and ACE at approx. 2-30 MeV/nucleon) and characteristics of the identified IMF-source regions. The study is based on 24 SEP events, identified as a statistically-significant increase in approx. 20 MeV protons and occurring in 1998 and 2003-2006, when the rate of newly-emergent solar magnetic flux and CMEs was lower than in solar-maximum years and the field-line tracing is therefore more likely to be successful. We find that the gradual SEP Fe/O is correlated with the field strength at the IMF-source, with the largest enhancements occurring when the footpoint field is strong, due to the nearby presence of an active region. In these cases, other elemental ratios show a strong charge-to-mass (q/M) ordering, at least on average, similar to that found in impulsive events. These results lead us to suggest that magnetic reconnection in footpoint regions near active regions bias the heavy-ion composition of suprathermal seed ions by processes qualitatively similar to those that produce larger heavy-ion enhancements in impulsive SEP events. To address potential technical concerns about our analysis, we also discuss efforts to exclude impulsive SEP events from our event sample

    Identification of Partial Discharge Through Cable-Specific Adaption and Neural Network Ensemble

    Full text link
    [EN] This paper proposes to administer a multi-step artificial intelligence approach with an ensemble of adaptive neural networks (NNs) trained on 50000 samples to identify partial discharge (PD) diagnostic measurements for in-service medium voltage (MV) power cables. To evaluate the performance of the algorithm, a case study was performed on cables deliberately selected to contain both uncomplicated measurements and disruptive irregularities representative of conditions during field testing. The experimental test results prove that the proposed cable-specific adaptation improves PD identification accuracy, with further increment through the NN ensembles. The main contribution of the approach is in both the cable-specific adaption and the NN ensemble being applied to MV cable field measurements.Yeo, J.; Jin, H.; Rodrigo Mor, A.; Yuen, C.; Tushar, W.; Saha, TK.; Seng Ng, C. (2021). Identification of Partial Discharge Through Cable-Specific Adaption and Neural Network Ensemble. IEEE Transactions on Power Delivery. 1-10. https://doi.org/10.1109/TPWRD.2021.3093670S11

    Effects of a group-based lifestyle medicine for depression : a pilot randomized controlled trial

    Get PDF
    Given the growing evidence that a range of lifestyle factors are involved in the etiology of depression, a ‘lifestyle medicine’ approach can be potentially safe and cost-effective to prevent or treat depression. To examine the effects and acceptability of a group-based, integrative lifestyle medicine intervention as a standalone treatment for managing depressive symptoms, a pilot randomized controlled trial (RCT) was conducted in a Chinese adult population in 2018. Participants (n = 31) with PHQ-9 score above the cut-off of ≥ 10, which was indicative of moderate to severe depression, were recruited from the general community in Hong Kong and randomly assigned to lifestyle medicine group (LM group) or care-as-usual group (CAU group) in a ratio of 1:1. Participants in the LM group received 2-hour group sessions once per week for six consecutive weeks, which covered diet, exercise, mindfulness, psychoeducation, and sleep management. Linear mixed-effects model analyses showed that the LM group had a significant reduction in PHQ-9 scores compared to the CAU group at immediate posttreatment and 12-week posttreatment follow-up (d = 0.69 and 0.73, respectively). Moreover, there were significantly greater improvements in anxiety, stress, and insomnia symptoms (measured by DASS-21 and ISI) at all time points in the LM group (d = 0.42–1.16). The results suggests that our 6-week group-based, integrative lifestyle intervention program is effective in lowering depressive, anxiety, stress, and insomnia symptoms in the Chinese population. Further studies in clinical populations with a larger sample size and longer follow-up are warranted
    • …
    corecore