Effects of High Intensity Ultrasound on BSCCO-2212 Superconductor

Slurries of powdered Bi2Sr2CaCu2O8+x superconductor in low volatility alkanes were treated with intense ultrasound. Significant enhancements of magnetic irreversibility as well as transport critical current are reported. The effects are dependent on the concentration of the slurry and are optimal for 1.5% wt. slurry loading. Electron microscopy shows that ultrasonic treatment leads to a change in grain morphology and intergrain welding. The observed enhancement of superconducting properties is consistent with the limitations in critical currents in BSCCO superconductor being due to intergrain coupling rather than intragrain pinning strength.Comment: 3 page

High-Performance Multi-Mode Ptychography Reconstruction on Distributed GPUs

Ptychography is an emerging imaging technique that is able to provide wavelength-limited spatial resolution from specimen with extended lateral dimensions. As a scanning microscopy method, a typical two-dimensional image requires a number of data frames. As a diffraction-based imaging technique, the real-space image has to be recovered through iterative reconstruction algorithms. Due to these two inherent aspects, a ptychographic reconstruction is generally a computation-intensive and time-consuming process, which limits the throughput of this method. We report an accelerated version of the multi-mode difference map algorithm for ptychography reconstruction using multiple distributed GPUs. This approach leverages available scientific computing packages in Python, including mpi4py and PyCUDA, with the core computation functions implemented in CUDA C. We find that interestingly even with MPI collective communications, the weak scaling in the number of GPU nodes can still remain nearly constant. Most importantly, for realistic diffraction measurements, we observe a speedup ranging from a factor of $10$ to $10^3$ depending on the data size, which reduces the reconstruction time remarkably from hours to typically about 1 minute and is thus critical for real-time data processing and visualization.Comment: work presented in NYSDS 201

Non-ancient solution of the Ricci flow

For any complete noncompact K$\ddot{a}$hler manifold with nonnegative and bounded holomorphic bisectional curvature,we provide the necessary and sufficient condition for non-ancient solution to the Ricci flow in this paper.Comment: seven pages, latex fil

Guest-responsive polaritons in a porous framework: chromophoric sponges in optical QED cavities

Introducing porous material into optical cavities is a critical step toward the utilization of quantum-electrodynamical (QED) effects for advanced technologies, e.g. in the context of sensing. We demonstrate that crystalline, porous metal–organic frameworks (MOFs) are well suited for the fabrication of optical cavities. In going beyond functionalities offered by other materials, they allow for the reversible loading and release of guest species into and out of optical resonators. For an all-metal mirror-based Fabry–Perot cavity we yield strong coupling (∼21% Rabi splitting). This value is remarkably large, considering that the high porosity of the framework reduces the density of optically active moieties relative to the corresponding bulk structure by ∼60%. Such a strong response of a porous chromophoric scaffold could only be realized by employing silicon-phthalocyanine (SiPc) dyes designed to undergo strong J-aggregation when assembled into a MOF. Integration of the SiPc MOF as active component into the optical microcavity was realized by employing a layer-by-layer method. The new functionality opens up the possibility to reversibly and continuously tune QED devices and to use them as optical sensors

Correction: Guest-responsive polaritons in a porous framework: chromophoric sponges in optical QED cavities

Correction for ‘Guest-responsive polaritons in a porous framework: chromophoric sponges in optical QED cavities’ by Ritesh Haldar et al., Chem. Sci., 2020, DOI: 10.1039/d0sc02436

Creating an International Forage and Grasslands Curriculum

Grasslands cover nearly 2/3 of the land masses of the world and make up 1/4 of the earth\u27s surface. Although various regions of the world have different names for their grasslands, common management principles govern maintaining and improving these lands for the food production and environmental services they provide. There is much talk today about “finding the balance between environmental protection and economic development” but there is little evidence of knowledge about grassland ecosystems being translated into effectively implemented policies designed to restore degraded grasslands. In contrast, there are many examples of the tragic consequences of economic development rather than biological capacity driving decision-making. Historically, people were connected with the land and understood the soil, plant, animal, human “circle of life.” This understanding led to appropriate management. Today, the vast majority of the developed world has little understanding of these natural processes and increasing percentages of the developing world live in cities and are disconnected from the natural ecosystems that service them. Even those few studying agricultural sciences have little appreciation for the scope and diversity of grasslands present in the world. Far fewer have an understanding of the importance of grasslands management principles and needed supporting policies. Thus, there is a need for teaching materials that can be used worldwide to convey the importance and proper management of grasslands and forage-livestock systems