Satellite Entry Research Articles

Shot range estimation of shotgun grain-loaded cartridges

Commercial grain-loaded cartridges for shotguns have been recently associated with injuries and fatalities. These cartridges are generally used as a scare gun for large animals, with a little probability of causing harm. Almost all grain-loaded cartridges contain one type of cereal grain, such as bulgur wheat, wheat or vetch seed, instead of lead pellets. Our study aimed to investigate the shot range estimation of grain-loaded cartridges and assess the variations from conventional lead pellet cartridges.In this study, eight different brands of grain-loaded cartridges were used. The inspections and measurements were made with cartridges that contain cereal grains, gunpowder and wads. Shots were made from 50, 100, 200, 300, 500cm with modified and improved cylinder chokes. Diameter of grain distribution patterns on targets were measured. These measurements were evaluated statistically considering brand, choke and distance variables.Both satellite entry holes and central entry holes were detected in all shots that were fired from 50cm distance. The smallest average diameter of grain distribution pattern between 8 different brands were measured as 14.3, 38.3, 58.5 and 83.4cm for 100, 200, 300 and 500cm respectively with modified choke. Gathered data from this study was compared with the studies conducted with conventional cartridges and differences were determined. It was detected that the grain-loaded cartridges showed much wider distribution on targets at the same shooting distance with the same and similar barrel lengths and choke values compared to conventional lead pellet containing cartridges.

The multiplicity and anisotropy of galactic satellite accretion

We study the incidence of group and filamentary dwarf galaxy accretion into Milky Way (MW) mass haloes using two types of hydrodynamical simulations: EAGLE, which resolves a large cosmological volume, and the AURIGA suite, which are very high resolution zoom-in simulations of individual MW-sized haloes. The present-day 11 most massive satellites are predominantly (75%) accreted in single events, 14% in pairs and 6% in triplets, with higher group multiplicities being unlikely. Group accretion becomes more common for fainter satellites, with 60% of the top 50 satellites accreted singly, 12% in pairs, and 28% in richer groups. A group similar in stellar mass to the Large Magellanic Cloud (LMC) would bring on average 15 members with stellar mass larger than $10^4{~\rm M_\odot}$. Half of the top 11 satellites are accreted along the two richest filaments. The accretion of dwarf galaxies is highly anisotropic, taking place preferentially perpendicular to the halo minor axis, and, within this plane, preferentially along the halo major axis. The satellite entry points tend to be aligned with the present-day central galaxy disc and satellite plane, but to a lesser extent than with the halo shape. Dwarfs accreted in groups or along the richest filament have entry points that show an even larger degree of alignment with the host halo than the full satellite population. We also find that having most satellites accreted as a single group or along a single filament is unlikely to explain the MW disc of satellites.

Quenching of satellite galaxies at the outskirts of galaxy clusters

We find, using cosmological simulations of galaxy clusters, that the hot X-ray emitting intra-cluster medium (ICM) enclosed within the outer accretion shock extends out to $R_{\rm shock}\sim(2 - 3) R_{\rm vir}$, where $R_{\rm vir}$ is the standard virial radius of the halo. Using a simple analytic model for satellite galaxies in the cluster, we evaluate the effect of ram pressure stripping on the gas in the inner discs and in the haloes at different distances from the cluster centre. We find that significant removal of star-forming disc gas occurs only at $r \lesssim 0.5 R_{\rm vir}$, while gas removal from the satellite halo is more effective and can occur when the satellite is found between $ R_{\rm vir}$ and $R_{\rm shock}$. Removal of halo gas sets the stage for quenching of the star formation by starvation over $2\textrm{--}3\,\mathrm{Gyr}$, prior to the satellite entry to the inner cluster halo. This scenario explains the presence of quenched galaxies, preferentially discs, at the outskirts of galaxy clusters, and the delayed quenching of satellites compared to central galaxies.

The effect of satellite entry on cable television prices and product quality

How has the entry of satellite television affected the pricing and product quality of incumbent cable firms' programming packages? I estimate a model in which firms compete over both price and product quality (as determined by what channels are offered). Satellite entry typically causes cable firms to raise quality and lower price. However, in some markets, cable optimally responds by raising both price and quality or by lowering both price and quality. A counterfactual scenario that eliminates quality competition results in, on average, softer price competition and lower aggregate consumer surplus, but greater surplus for consumers with weaker preferences for quality.

The Effect of Satellite Entry on Product Quality for Cable Television

In vertically differentiated markets, the effects firm entry are contingent upon whether incumbent firms can respond to entry by adjusting product quality addition to simply lowering prices. Using market-level data, I estimate a structural model supply and demand for subscription television that takes into account the endogeneity quality choice. Using counterfactual analysis, I decompose the effect satellite entry on existing cable into two components: the conventional price response and the effect endogenous quality adjustments (measured by changes programming content). Consistent with the empirical observation that cable prices rose during the 1990s and early 2000s in spite of increasing competition, I find that raising both price and quality for the most comprehensive subscription package--i.e., competing head-to-head--is the rational response to entry by cable systems markets with relatively homogeneous consumer types. Elsewhere, incumbents respond less aggressively and relegate themselves to being the low-end provider. When an entrant credibly commits to serving consumers with the highest preferences for quality, competition over both price and quality lowers the welfare gains due to entry, relative to pure price competition. In particular, head-to-head competition results crowding quality choices toward the high end the market and inefficiently low product differentiation. In such cases, consumers with weak quality preferences may actually become worse off following entry. The evidence also suggests that the observed degradation the lowest-quality cable tier many markets during this time period--while commonly seen as an attempt to evade price regulation--may actually have been welfare-enhancing.

The Effect of Satellite Entry on Product Quality for Cable Television

In vertically differentiated markets, the effects of firm entry are contingent upon whether incumbent firms can respond to entry by adjusting product quality in addition to simply lowering prices. Using market-level data, I estimate a structural model of supply and demand for subscription television that takes into account the endogeneity of quality choice. Using counterfactual analysis, I decompose the effect of satellite entry on existing cable into two components: the conventional price response and the effect of endogenous quality adjustments (measured by changes in programming content). Consistent with the empirical observation that cable prices rose during the 1990s and early 2000s "in spite of" increasing competition, I find that raising both price and quality for the most comprehensive subscription package--i.e., competing "head-to-head"--is the rational response to entry by cable systems in markets with relatively homogeneous consumer types. Elsewhere, incumbents respond less

Local gradient of energetic ion flux during dipolarization on 6–7 RE

Injections of energetic particles and dipolarization of magnetic field are well-known signatures of magnetospheric substorm in the near-earth region of plasma sheet. However, the physical processes associated with these phenomena are not fully understood. The pressure gradient and anisotropy are significant parameters for understanding of physics of the substorm development. Kozelova et al. [Geomagn. Aeronomy 26, 621, 1986] found in study of GEOS 2 data that the anticorrelation between the proton and electron fluxes is connected with the western edge of the expansive auroral bulge (with the spatial extent >100 km and with duration near 10 min). Inside the active region, where the dipolarization is observed, the proton fluxes are reduced and the electric field is directed westward. The increase (or decrease) of proton flux may be interpreted as satellite entry into the region of enhanced (or decreased) plasma pressure since energetic protons give the main contribution to the pressure. Here we examined the CRRES data from several detectors which measured the particles in a different directions. We found the similar variations of the energetic particle fluxes (protons >37 keV and electrons >21.5 keV) associated with the local dipolarization, however these variations were observed during the shorter interval of 30–40 s [Kozelova et al., Geomagn. Aeronomy 43, 513, 2003]. Sometimes the azimuthal anisotropy of proton fluxes of different energy may be different and the flux variations are noncoherent within a small spatial region comparable to the proton gyroradius (here from 350 to 1400 km). Dispersionless energetic electron injection coincides with the dipolarization and with the drop of the 37–54 keV proton flux. This proton drop begins eastward of the CRRES and then expand westward with the velocity of 130–350 km/s.

On Satellite Umbra/Penumbra Entry and Exit Positions

The problem of computing Earth satellite entry and exit positions through the Earth’s umbra and penumbra, for satellites in elliptical orbits, is solved without the use of a quartic equation. A condition for existence of a solution in the case of a cylindrical shadow is given. This problem is of interest in case one would like to include perturbation force resulting from solar radiation pressure. Most satellites (including geosynchronous) experience periodic eclipses behind the Earth. Of course when the satellite is eclipsed, it’s not exposed to solar radiation pressure. When we need extreme accuracy, we must develop models that turn the solar radiation calculations “on” and “off,” as appropriate, to account for these periods of inactivity.