5,328 research outputs found
Constraining dark photon model with dark matter from CMB spectral distortions
Many extensions of Standard Model (SM) include a dark sector which can
interact with the SM sector via a light mediator. We explore the possibilities
to probe such a dark sector by studying the distortion of the CMB spectrum from
the blackbody shape due to the elastic scatterings between the dark matter and
baryons through a hidden light mediator. We in particular focus on the model
where the dark sector gauge boson kinetically mixes with the SM and present the
future experimental prospect for a PIXIE-like experiment along with its
comparison to the existing bounds from complementary terrestrial experiments.Comment: 6 pages, 8 figure
Does Monetary Policy Help Least Those Who Need It Most?
We estimate the impact of U.S. monetary policy on the cross-sectional distribution of state economic activity for a 35-year panel. Our results indicate that the effects of policy have a significant history dependence, in that relatively slow growth regions contract more following contractionarymonetary shocks. Moreover, policy is asymmetric, in that expansionary shocks have less of a beneficial impact upon relatively slow growth areas. As a result, we conclude that monetary policy on average widens the dispersion of growth rates among U.S. states, and those locations initially at the low end of the cross-sectional distribution benefit least from any given change inmonetary policy.Monetary policy, asymmetric effects, state dependence, regional business cycles
Searching for Axino-Like Particle at Fixed Target Experiments
We investigate the detectability of axino-like particle, which is defined as
a supersymmetric partner of axion-like particle and can be a good candidate for
dark matter in our Universe. Especially, we consider the fixed target
experiments to search for the light axino-like particle with a neutralino as
the next-to-lightest supersymmetric particle. We calculate the production and
decay rate of neutralinos and the consequent number of events (such as photons
and charged leptons) that are produced when the neutralinos decay to the
axino-like particles.Comment: 10 pages, 7 figures, Published in Physics of the Dark Univers
Conversion of Municipal Solid Wastes into Biochar through Hydrothermal Carbonization
In this study, the hydrothermal treatment of municipal solid wastes (MSWs) for the production of biochar as a renewable solid fuel was investigated. The properties of surrogate MSWs and mixtures of newspaper and vegetables were greatly improved by hydrothermal treatment and were similar to those of coal-like fuel substances. Hydrothermal treatment increased the calorific value, the fixed carbon, and carbon contents. The composition of the major biomass components of MSW was found to affect the alternation of their physical and chemical properties significantly. These characteristic changes in pure cellulose, hemicellulose, and lignin were similar to those of coalification at the hydrothermal reaction temperature range of 150–280°C. The treated products became a solid fuel substance, the characteristics of which corresponded with fuel between lignite and sub-bituminous coal. The results of this study indicate that hydrothermal treatment can be used as an effective means to generate highly energy-efficient renewable fuel resources using MSWs
Performance and Fouling in Pre-Denitrification Membrane Bioreactors Treating High-Strength Wastewater from Food Waste Disposers
The study investigated the performance of the pre-denitrification membrane bioreactor (MBR) process to treat high-strength wastewater generated from food waste disposals. Extracellular polymeric substances (EPS) as membrane foulant and microbial community profiles were analyzed under different hydraulic retention time (HRT) operation conditions. The pre-denitrification MBR was effective for treating food wastewater with high chemical oxygen demand (COD)/N resulting in high total nitrogen (TN) removal efficiency. The operational data showed that effluent qualities in terms of COD, TN, and TP improved with longer HRT. However, membrane fouling potential as shown by specific membrane fouling rate and specific resistance to filtration (SRF) increased as HRT increased. The longer HRT conditions or lower influent loading led to higher levels of bound EPS while HRT did not show large effects on the level of soluble microbial products (SMP). The restriction fragment length polymorphism (RFLP) analysis showed similar microbial banding patterns from the sludges generated under different HRT conditions, indicating that HRT had minimal effects on the composition of microbial communities in the system. All these results suggest that the MBR with pre-denitrification is a feasible option for treating high-strength food wastewater and that different HRT conditions could affect the operational performance and the fouling rate, which is governed via changes in microbial responses through EPS in the system
The Effect Of The Relationships Between Affiliated Firms On Direction Of Income Shifting Within Business Groups
In this study, we examined how income shifting performs among affiliates in a business group to maximize the benefits of the entire business group in terms of minimizing the tax burden, with a particular focus on the direction of income shifting between affiliates within the business group. We find that tax-related decision-making for the entire business group is affected by the relationships between the affiliated firms, that is, the ownership structure of the whole business group. To analyze the ownership structure, we use centrality measures in a social network analysis. The results show that affiliates with the higher outdegree-centrality; that is, firms investing more shareholdings in other affiliates have a tendency to perform more income shifting. On the other hand, the affiliates with high indegree-centrality, that is, firms which are owned by other affiliates, were revealed to be given the income shifting from other affiliated firms to minimize the tax burden of the entire business group
Haptic Stylus and Empirical Studies on Braille, Button, and Texture Display
This paper presents a haptic stylus interface with a
built-in compact tactile display module and an impact module
as well as empirical studies on Braille, button, and texture
display. We describe preliminary evaluations verifying the
tactile display's performance indicating that it can
satisfactorily represent Braille numbers for both the normal
and the blind. In order to prove haptic feedback capability of
the stylus, an experiment providing impact feedback mimicking
the click of a button has been conducted. Since the developed
device is small enough to be attached to a force feedback
device, its applicability to combined force and tactile
feedback display in a pen-held haptic device is also
investigated. The handle of pen-held haptic interface was
replaced by the pen-like interface to add tactile feedback
capability to the device. Since the system provides
combination of force, tactile and impact feedback, three
haptic representation methods for texture display have been
compared on surface with 3 texture groups which differ in
direction, groove width, and shape. In addition, we evaluate
its capacity to support touch screen operations by providing
tactile sensations when a user rubs against an image displayed
on a monitor
Numerical analysis of dielectric micro-particle motion in a fluid and electric field
We present numerical analysis of a coupled problem composed of fluidics,
electromagnetic and particle dynamics. The forces acting on the dielectric micro-particle
consist of a dielectrophoretic(DEP) force, drag force and gravitational force in the proposed
analysis model. DEP force and drag force are calculated using the distribution of the electric
field and fluid velocity field to analyze the characteristic of the micro-particle motion. The
forces exerted by each field are driving terms in the Newton’s equation for particle motion.
The designed particle separating device, which has the one inlet and the two outlets, is
simulated to validate proposed numerical scheme. The analysis results show the trace of the
micro-particles can be analyzed using the proposed numerical approach
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