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  1. The expectation of people and futurists is that all respectable cities will become Smart Cities in the near future. Two main barriers stand in the way of the evolution of cities. First is cost, the transformation into a smart city is expensive (e.g., between $30 Million and $40 Billion) and only a few cities are able to obtain the resources required for upgrades. Second, many citizens equate the data collection and surveillance of smart city technology with aggressive infringements on privacy. In this paper, we describe how citizens, city planners, and companies can develop smart cities that do not requiremore »crippling loans and are respectful of privacy.« less
  2. Abstract We present the results of a search for core-collapse supernova neutrinos, using long-term KamLAND data from 2002 March 9 to 2020 April 25. We focus on the electron antineutrinos emitted from supernovae in the energy range of 1.8–111 MeV. Supernovae will make a neutrino event cluster with the duration of ∼10 s in the KamLAND data. We find no neutrino clusters and give the upper limit on the supernova rate to be 0.15 yr −1 with a 90% confidence level. The detectable range, which corresponds to a >95% detection probability, is 40–59 kpc and 65–81 kpc for core-collapse supernovaemore »and failed core-collapse supernovae, respectively. This paper proposes to convert the supernova rate obtained by the neutrino observation to the Galactic star formation rate. Assuming a modified Salpeter-type initial mass function, the upper limit on the Galactic star formation rate is <(17.5–22.7) M ⊙ yr −1 with a 90% confidence level.« less
    Free, publicly-accessible full text available July 1, 2023
  3. Abstract We present the results of a time-coincident event search for low-energy electron antineutrinos in the KamLAND detector with gamma-ray bursts (GRBs) from the Gamma-ray Coordinates Network and Fermi Gamma-ray Burst Monitor. Using a variable coincidence time window of ±500 s plus the duration of each GRB, no statistically significant excess above the background is observed. We place the world’s most stringent 90% confidence level upper limit on the electron antineutrino fluence below 17.5 MeV. Assuming a Fermi–Dirac neutrino energy spectrum from the GRB source, we use the available redshift data to constrain the electron antineutrino luminosity and effective temperature.
    Free, publicly-accessible full text available March 1, 2023
  4. Abstract We report the result of a search for neutrinos in coincidence with solar flares from the GOES flare database. The search was performed on a 10.8 kton-year exposure of KamLAND collected from 2002 to 2019. This large exposure allows us to explore previously unconstrained parameter space for solar flare neutrinos. We found no statistical excess of neutrinos and established 90% confidence level upper limits of 8.4 × 10 7 cm −2 (3.0 × 10 9 cm −2 ) on the electron antineutrino (electron neutrino) fluence at 20 MeV normalized to the X12 flare, assuming that the neutrino fluence ismore »proportional to the X-ray intensity.« less
    Free, publicly-accessible full text available January 1, 2023
  5. Abstract We report on a search for electron antineutrinos ( ν ¯ e ) from astrophysical sources in the neutrino energy range 8.3–30.8 MeV with the KamLAND detector. In an exposure of 6.72 kton-year of the liquid scintillator, we observe 18 candidate events via the inverse beta decay reaction. Although there is a large background uncertainty from neutral current atmospheric neutrino interactions, we find no significant excess over background model predictions. Assuming several supernova relic neutrino spectra, we give upper flux limits of 60–110 cm −2 s −1 (90% confidence level, CL) in the analysis range and present a model-independentmore »flux. We also set limits on the annihilation rates for light dark matter pairs to neutrino pairs. These data improve on the upper probability limit of 8 B solar neutrinos converting into ν ¯ e , P ν e → ν ¯ e < 3.5 × 10 − 5 (90% CL) assuming an undistorted ν ¯ e shape. This corresponds to a solar ν ¯ e flux of 60 cm −2 s −1 (90% CL) in the analysis energy range.« less
    Free, publicly-accessible full text available January 1, 2023
  6. Abstract. Reactive mercury (RM), the sum of both gaseous oxidized Hg and particulatebound Hg, is an important component of the global atmospheric mercury cycle,but measurement currently depends on uncalibrated operationally definedmethods with large uncertainty and demonstrated interferences and artifacts.Cation exchange membranes (CEMs) provide a promising alternative methodologyfor quantification of RM, but method validation and improvements are ongoing.For the CEM material to be reliable, uptake of gaseous elemental mercury(GEM) must be negligible under all conditions and RM compounds must becaptured and retained with high efficiency. In this study, the performance ofCEM material under exposure to high concentrations of GEM (1.43×106 tomore »1.85×106 pg m−3) and reactive gaseous mercurybromide (HgBr2 ∼5000 pg m−3) was explored using acustom-built mercury vapor permeation system. Quantification of totalpermeated Hg was measured via pyrolysis at 600 ∘C and detectionusing a Tekran® 2537A. Permeation tests wereconducted over 24 to 72 h in clean laboratory air, with absolute humiditylevels ranging from 0.1 to 10 g m−3 water vapor. GEM uptake by the CEMmaterial averaged no more than 0.004 % of total exposure for all testconditions, which equates to a non-detectable GEM artifact for typicalambient air sample concentrations. Recovery of HgBr2 on CEM filters wason average 127 % compared to calculated total permeated HgBr2 based onthe downstream Tekran® 2537A data. The lowHgBr2 breakthrough on the downstream CEMs (< 1 %) suggests thatthe elevated recoveries are more likely related to suboptimal pyrolyzerconditions or inefficient collection on the Tekran® 2537A gold traps.« less