1,036 research outputs found
The Year in Review, 2019-2020
The work of the Pedagogy and Theatre of the Oppressed organization and its members remains vital. As we reflect on the 2019-2020 organization cycle, we share with you the ways in which the PTO organization has continued to grow amidst these global shifts. We continue to embrace the challenges and opportunities of this moment and continue to support people whose work challenges oppressive systems by promoting critical thinking and social justice through liberatory theatre and popular education
Revisiting the Flowers-Ruderman instability of magnetic stars
In 1977, Flowers and Ruderman described a perturbation that destabilises a
purely dipolar magnetic field in a fluid star. They considered the effect of
cutting the star in half along a plane containing the symmetry axis and
rotating each half by 90\degr in opposite directions, which would cause the
energy of the magnetic field in the exterior of the star to be greatly reduced,
just as it happens with a pair of aligned magnets. We formally solve for the
energy of the external magnetic field and check that it decreases monotonously
along the entire rotation. We also describe the instability using perturbation
theory, and see that it happens due to the work done by the interaction of the
magnetic field with surface currents. Finally, we consider the stabilising
effect of adding a toroidal field by studying the potential energy perturbation
when the rotation is not done along a sharp cut, but with a continuous
displacement field that switches the direction of rotation across a region of
small but finite width. Using these results, we estimate the relative strengths
of the toroidal and poloidal field needed to make the star stable to this
displacement and see that the energy of the toroidal field required for
stabilisation is much smaller than the energy of the poloidal field. We also
show that, contrary to a common argument, the Flowers-Ruderman instability
cannot be applied many times in a row to reduce the external magnetic energy
indefinitely.Comment: Uploaded complete version with corrections from the MNRAS refere
Economic Analysis of Wildlife Management Costs in the U.S. Forest Service, Northern Region
Paper published as Bulletin 47 in the UM Bulletin Forestry Series.https://scholarworks.umt.edu/umforestrybulletin/1030/thumbnail.jp
Hindered Aluminum Plating and Stripping in Urea/NMA/Al(OTF) as a Cl-Free Electrolyte for Aluminum Batteries
Conventional electrolytes for aluminum metal batteries are highly corrosive because they must remove the AlO layer to enable plating and stripping. However, such corrosiveness impacts the stability of all cell parts, thus hampering the real application of aluminum-metal batteries. The urea/NMA/Al(OTF) electrolyte is a non-corrosive alternative to the conventional [EMImCl]: AlCl ionic liquid electrolyte (ILE). Unfortunately, this electrolyte demonstrates poor Al plating/stripping, probably because (being not corrosive) it cannot remove the AlO passivation layer. This work proves that no plating/stripping occurs on the Al electrode despite modifying the Al surface. We highlight how urea/NMA/Al(OTF) electrolyte and the state of the Al electrode surface impact the interphase layer formation and, consequently, the likelihood and reversibility of Al plating/stripping. We point up the requirement for carefully drying electrolyte mixture and components, as water results in hydrogen evolution reaction and creation of an insulating interphase layer containing Al(OH), AlF, and re-passivated Al oxide, which finally blocks the path for the possible Al plating/stripping
Socio-cultural influences upon knowledge of sexually transmitted infections: a qualitative study with heterosexual middle-aged adults in Scotland
There has been a recent global increase in sexually transmitted infections (STIs) including HIV among
adults aged over 45. Limited evidence exists regarding middle-aged adults’ knowledge of STIs other than HIV. This
qualitative study sought to understand middle-aged adults’ knowledge of STIs within a socio-cultural context.
Individual interviews, based on a life-course approach, were conducted with 31 recently sexually active
heterosexual men and women. Participants were aged between 45 and 65 and of mixed relationship status
(14 were single, 17 in a relationship). Thematic analysis identified four key findings, including: “engagement with
STI-related knowledge”; “general knowledge of STIs”; “learning about STIs from children”; and “limited application
of knowledge”. The findings allow insight into a neglected area, and indicate that socio-cultural factors influence
middle-aged adults’ STI-related knowledge acquisition throughout the life course. These are important implications
for the prevention of STIs, particularly in addressing the on-going stigmatisation of STIs in older age groups
Engaging with a Prevention Approach: System Supports Needed in Child Abuse and Neglect Prevention
Public policy has been shifting from child abuse and neglect (CAN) intervention toward prevention, using public health style frameworks, which emphasize shared community and legislative responsibilities to support families (Browne, 2014; CDC, 2014). Analysis of qualitative data from statewide focus groups held in 2019 in Alabama with 99 community-based CAN prevention workers shows strengths in community collaboration, but also, struggles to help families meet basic needs because of lack of community resources, such as transportation and quality child care, and other barriers, including stigma. The results demonstrate confusion between prevention, which is intended to build family resilience to avert crisis, and intervention, meant to reunite families after child protection services involvement. We recommend researchers consistently link CAN research to prevention frameworks so as to build meaningful understanding how to create better prevention programs. Future practitioners should understand prevention, and be prepared to document their work so as to demonstrate need
Enabling Modular Autonomous Feedback-Loops in Materials Science through Hierarchical Experimental Laboratory Automation and Orchestration
Materials acceleration platforms (MAPs) operate on the paradigm of integrating combinatorial synthesis, high-throughput characterization, automatic analysis, and machine learning. Within a MAP, one or multiple autonomous feedback loops may aim to optimize materials for certain functional properties or to generate new insights. The scope of a given experiment campaign is defined by the range of experiment and analysis actions that are integrated into the experiment framework. Herein, the authors present a method for integrating many actions within a hierarchical experimental laboratory automation and orchestration (HELAO) framework. They demonstrate the capability of orchestrating distributed research instruments that can incorporate data from experiments, simulations, and databases. HELAO interfaces laboratory hardware and software distributed across several computers and operating systems for executing experiments, data analysis, provenance tracking, and autonomous planning. Parallelization is an effective approach for accelerating knowledge generation provided that multiple instruments can be effectively coordinated, which the authors demonstrate with parallel electrochemistry experiments orchestrated by HELAO. Efficient implementation of autonomous research strategies requires device sharing, asynchronous multithreading, and full integration of data management in experimental orchestration, which to the best of the authors’ knowledge, is demonstrated for the first time herein
Modification of Al Surface via Acidic Treatment and its Impact on Plating and Stripping
Amorphous AlO film that naturally exists on any Al substrate is a critical bottleneck for the cyclic performance of metallic Al in rechargeable Al batteries. The so-called electron/ion insulator Al oxide slows down the anode\u27s activation and hinders Al plating/stripping. The AlO film induces different surface properties (roughness and microstructure) on the metal. Al foils present two optically different sides (shiny and non-shiny), but their surface properties and influence on plating and stripping have not been studied so far. Compared to the shiny side, the non-shiny one has a higher (~28 %) surface roughness, and its greater concentration of active sites (for Al plating and stripping) yields higher current densities. Immersion pretreatments in Ionic-Liquid/AlCl-based electrolyte with various durations modify the surface properties of each side, forming an electrode-electrolyte interphase layer rich in Al, Cl, and N. The created interphase layer provides more tunneling paths for better Al diffusion upon plating and stripping. After 500 cycles, dendritic Al deposition, generated active sites, and the continuous removal of the Al metal and oxide cause accelerated local corrosion and electrode pulverization. We highlight the mechanical surface properties of cycled Al foil, considering the role of immersion pretreatment and the differences between the two sides
Baryon superfluidity and neutrino emissivity of neutron stars
For neutron stars with hyperon-mixed core, neutrino emissivity is studied
under the equation of state, obtained by introducing repulsive three-body force
universal for all baryons so as to assure the maximum mass compatible with the
observation. By paying attention to the density-dependence of critical
temperatures of baryon superfluids, which reflect the nature of baryon-baryon
interaction and control neutron star cooling, we show what neutrino emission
processes are efficient in the regions with and without hyperon mixing and
remark its implications related to neutron star cooling.Comment: 5pages, 4 figure
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