3,924 research outputs found
Expanding Carceral Frontiers: The 100-Mile Border Zone and Constituting Latinx Political Subjectivity
The thesis has two interrelated concerns. The first explores the emergence of the 100-mile border zone in order to study how the U.S. has expanded its borders inward and redefined notions of national security and carcerality. The second will define the 100-mile border as a carceral frontier that has emerged from previous years of racial security operations such as âOperation Wetbackâ in 1953. Moreover, I will demonstrate how the 100-mile border zone, a carceral frontier, blends the logic of security and the carceral in order to create a space of total state control. This inward turn of the 100-mile border zone and the security and carcerality of this space reveals much about the constitution of the sovereign stateâs right to define and secure its borders within the nation, the rights of the state over that of the citizen, a citizen\u27s right to free movement and due process, and the racial dynamics of security actions. To explore this contradictory logic of security, I conduct an analysis of security language on border and immigration âoperationsâ that constituted the emergence of the 100-mile border zone since 1953. Through this analysis, I will argue that the 100-mile border zone, as a carceral frontier, is a new theoretical development in Critical Carceral Studies. In this way, this thesis will engage in Securitization Studies, Border Theory, and Carceral theories. This type of analysis will reveal that the 100-mile border zone, and the making of this carceral frontier, is inextricably bound to the rights and status of Latinx
Electron Power-Law Spectra in Solar and Space Plasmas
Particles are accelerated to very high, non-thermal energies in solar and
space plasma environments. While energy spectra of accelerated electrons often
exhibit a power law, it remains unclear how electrons are accelerated to high
energies and what processes determine the power-law index . Here, we
review previous observations of the power-law index in a variety of
different plasma environments with a particular focus on sub-relativistic
electrons. It appears that in regions more closely related to magnetic
reconnection (such as the `above-the-looptop' solar hard X-ray source and the
plasma sheet in Earth's magnetotail), the spectra are typically soft ( 4). This is in contrast to the typically hard spectra ( 4) that are observed in coincidence with shocks. The difference
implies that shocks are more efficient in producing a larger non-thermal
fraction of electron energies when compared to magnetic reconnection. A caveat
is that during active times in Earth's magnetotail, values seem
spatially uniform in the plasma sheet, while power-law distributions still
exist even in quiet times. The role of magnetotail reconnection in the electron
power-law formation could therefore be confounded with these background
conditions. Because different regions have been studied with different
instrumentations and methodologies, we point out a need for more systematic and
coordinated studies of power-law distributions for a better understanding of
possible scaling laws in particle acceleration as well as their universality.Comment: 67 pages, 15 figures; submitted to Space Science Reviews; comments
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Electromagnetic Sensor and Actuator Attacks on Power Converters for Electric Vehicles
Alleviating range anxiety for electric vehicles (i.e., whether such vehicles
can be relied upon to travel long distances in a timely manner) is critical for
sustainable transportation. Extremely fast charging (XFC), whereby electric
vehicles (EV) can be quickly recharged in the time frame it takes to refuel an
internal combustion engine, has been proposed to alleviate this concern. A
critical component of these chargers is the efficient and proper operation of
power converters that convert AC to DC power and otherwise regulate power
delivery to vehicles. These converters rely on the integrity of sensor and
actuation signals. In this work the operation of state-of-the art XFC
converters is assessed in adversarial conditions, specifically against
Intentional Electromagnetic Interference Attacks (IEMI). The targeted system is
analyzed with the goal of determining possible weak points for IEMI, viz.
voltage and current sensor outputs and gate control signals. This work
demonstrates that, with relatively low power levels, an adversary is able to
manipulate the voltage and current sensor outputs necessary to ensure the
proper operation of the converters. Furthermore, in the first attack of its
kind, it is shown that the gate signal that controls the converter switches can
be manipulated, to catastrophic effect; i.e., it is possible for an attacker to
control the switching state of individual transistors to cause irreparable
damage to the converter and associated systems. Finally, a discussion of
countermeasures for hardware designers to mitigate IEMI-based attacks is
provided.Comment: Accepted by IEEE S&P Workshop on the Internet of Safe Things 202
Branding the nation: Towards a better understanding
This paper aims to clarify some misunderstanding about nation branding. It examines the origins and interpretations of the concept, and draws a comparison between nation branding and commercial branding. A new definition is offered that emphasises the need to shift from âbrandingâ the nation to nation image management
Energy Level Statistics of the U(5) and O(6) Symmetries in the Interacting Boson Model
We study the energy level statistics of the states in U(5) and O(6) dynamical
symmetries of the interacting boson model and the high spin states with
backbending in U(5) symmetry. In the calculations, the degeneracy resulting
from the additional quantum number is eliminated manually. The calculated
results indicate that the finite boson number effect is prominent. When
has a value close to a realistic one, increasing the interaction strength of
subgroup O(5) makes the statistics vary from Poisson-type to GOE-type and
further recover to Poisson-type. However, in the case of , they
all tend to be Poisson-type. The fluctuation property of the energy levels with
backbending in high spin states in U(5) symmetry involves a signal of shape
phase transition between spherical vibration and axial rotation.Comment: 38 pages, 13 figure
Influence of Si doping on InAs/GaAs quantum dot solar cells with AlAs cap layers
A novel all-optical forward-viewing photoacoustic probe using a flexible coherent fibre-optic bundle and a Fabry- Perot (FP) ultrasound sensor has been developed. The fibre bundle, along with the FP sensor at its distal end, synthesizes a high density 2D array of wideband ultrasound detectors. Photoacoustic waves arriving at the sensor are spatially mapped by optically scanning the proximal end face of the bundle in 2D with a CW wavelength-tunable interrogation laser. 3D images are formed from the detected signals using a time-reversal image reconstruction algorithm. The system has been characterized in terms of its PSF, noise-equivalent pressure and field of view. Finally, the high resolution 3D imaging capability has been demonstrated using arbitrary shaped phantoms and duck embryo
Si-Doped InAs/GaAs Quantum-Dot Solar Cell With AlAs Cap Layers
One of the requirements for strong subbandgap photon absorption in the quantum-dot intermediate-band solar cell (QD-IBSC) is the partial filling of the intermediate band. Studies have shown that the partial filling of the intermediate band can be achieved by introducing Si doping to the QDs. However, the existence of too many Si dopants leads to the formation of point defects and, hence, a reduction of photocurrent. In this study, the effect of Si doping on InAs/GaAs QD solar cells with AlAs cap layers is studied. The AlAs cap layers prevent the formation of the wetting layer during QD growth and reduce the Si doping density needed to achieve QD state filling. Furthermore, the passivation of defect states in the QD with moderate Si doping is demonstrated, which leads to an enhancement of the carrier lifetime in the QDs and, hence, the open-circuit voltage
Expression of monolysocardiolipin acyltransferase activity is regulated in concert with the level of cardiolipin and cardiolipin biosynthesis in the mammalian heart
BACKGROUND: Monolysocardiolipin acyltransferase (MLCL AT) catalyzes the acylation of monolysocardiolipin to cardiolipin in mammalian tissues. We previously reported that cardiac cardiolipin levels, MLCL AT and cardiolipin synthase activities were all elevated in rats made hyperthyroid by thyroxine treatment. In this study, we examined if cardiac mitochondrial MLCL AT activity was dependent upon the biosynthesis and level of cardiolipin in the heart. Rat heart mitochondrial MLCL AT activity was determined under conditions in which the levels of cardiac cardiolipin and cardiolipin synthase activity were either reduced or unaltered using four different disease models in the rat. In addition, these parameters were examined in a murine model of cardiac cell differentiation. RESULTS: In rats made hypothyroid by treatment with 6-n-propyl-2-thiouracil in the drinking water for 34 days, cardiac cardiolipin content was decreased 29% (p < 0.025) and this was associated with a 32% decrease (p < 0.025) in cardiolipin synthase and a 35% reduction (p < 0.025) in MLCL AT activities. Streptozotocin-induced diabetes or hyperinsulinemia in rats did not affect cardiac cardiolipin content nor MLCL AT and cardiolipin synthase activities. Finally, cardiolipin content, MLCL AT and cardiolipin synthase activities were unaltered during murine P19 teratocarcinoma cell differentiation into cardiac myocytes. In all models, phospholipase A(2) activities were unaltered compared with controls. CONCLUSION: We propose a general model in which the expression of MLCL AT activity is regulated in concert with the biosynthesis and level of cardiolipin in the heart
Modeling electron temperature profiles in the pedestal with simple formulas for ETG transport
This paper reports on the refinement (building on Ref.~\cite{hatch_22}) and
application of simple formulas for electron heat transport from electron
temperature gradient (ETG) driven turbulence in the pedestal. The formulas are
improved by (1) improving the parameterization for certain key parameters and
(2) carefully accounting for the impact of geometry and shaping in the
underlying gyrokinetic simulation database. Comparisons with nonlinear
gyrokinetic simulations of ETG transport in the MAST pedestal demonstrate the
model's applicability to spherical tokamaks in addition to standard aspect
ratio tokamaks. We identify bounds for model applicability: the model is
accurate in the steep gradient region, where the ETG turbulence is largely
slab-like, but accuracy decreases as the temperature gradient becomes weaker in
the pedestal top and the instabilities become increasingly toroidal in nature.
We use the formula to model the electron temperature profile in the pedestal
for four experimental scenarios while extensively varying input parameters to
represent uncertainties. In all cases, the predicted electron temperature
pedestal exhibits extreme sensitivity to separatrix temperature and density,
which has implications for core-edge integration. The model reproduces the
electron temperature profile for high scenarios but
not for low scenarios in which microtearing modes have been
identified. We develop a proof-of-concept model for MTM transport and explore
the relative roles of ETG and MTM in setting the electron temperature profile.
We propose that pedestal scenarios predicted for future devices should be
tested for compatibility with ETG transport
An Investigation of the Role of Radiative and Nonradiative Recombination Processes in InAs/GaAs 1âx Sb x Quantum Dot Solar Cells
An InAs/GaAs0.86 Sb 0.14 quantum dot solar cell and a GaAsSb control cell were investigated using temperature-dependent current densityâvoltage (JâV), external quantum efficiency, photoluminescence (PL), and electroluminescence (EL) measurements. Thermally activated defect states associated with the GaAsSb matrix material are found to account for the reduction of the performance of the solar cell. The rapid quenching of the PL and EL intensity, along with the shift (above 150 K) of the dominant recombination process during spontaneous emission (EL), further indicates the prevalence of nonradiative processes at elevated temperatures in these systems. These findings are also supported by a reduction in the open-circuit voltage at elevated temperatures in these devices
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