Forbush decreases geomagnetic and atmospheric effects cosmogenic nuclides

An overview and synthesis is given of recent developments that have occurred in the areas of Forbush decreases, geomagnetic and atmospheric effects, and cosmogenic nuclides. Experimental evidence has been found for substantial differences in the effects of the various types of interplanetary perturbations on cosmic rays, and for a dependence of these effects on the three-dimensional configuration of the interplanetary medium. In order to fully understand and to be able to simulate the solar cosmic ray particle access to the polar regions of the earth we need accurate models of the magnetospheric magnetic field. These models must include all major magnetospheric current systems (in particular the field aligned currents), and they should represent magnetically quiet time periods as well as different levels of geomagnetic activity. In the evolution of magnetospheric magnetic field models, cosmic ray and magnetospheric physicists should work closely together since cosmic ray measurements are a powerful additional tool in the study of the perturbed magnetosphere. In the field of cosmogenic nuclides, finally, exciting new results and developments follow in rapid succession. Thanks to new techniques and new isotopes the analysis of cosmic ray history has entered into a new dimension

Lawrence E. Marceau. Takebe Ayatari: A Bunjin Bohemian in Early Modern Japan

Review of Lawrence E. Marceau. Takebe Ayatari: A Bunjin Bohemian in Early Modern Japan, Ann Arbor: Center for Japanese Studies, University of Michigan, 2004. xxi, 369 pp. $69.00 (cloth).Early Modern Japan Networ

"Who am I . . . what significance do I have?" : Shifting rituals, receding narratives, and potential change of the goddess' identity in Gangamma traditions of south India

Abstract These narrative and ritual changes raise questions about what each individually creates, their relationship, and what is lost or gained in the changes I have observed. What is created with the addition of Sanskritic rituals to temple service (traditionally offered to puranic deities4 rather than gramadevatas ["village deities"] such as Gangamma), when middle-class aesthetics haveatepick impacted architectural temple changes, and when Gangamma's narratives recede from the public imagination? How is the goddess' identity potentially changing with these narrative and ritual shifts? These questions bring a performative lens to older questions of the relationships between ritual and narrative, which often prioritize one over the other.5 Ethnographic and performance analyses of Gangamma ritual and narrative traditions show the finely tuned ways in which they are both independent and codependent and the ways in which they both reflect and create--and have the potential to change--the identity of the goddess.Issue title: Transmissions and Transitions in Indian Oral Traditions

There are only two castes : men and women : negotiating gender as a female healer in South Asian Islam

In this essay, I examine how Amma perceives and negotiates this seemingly unorthodox position for "woman" in a pluralistic Muslim/Hindu society in which the public domain continues to be dominated by the male voice. Does she draw gender boundaries for the Muslim woman to include a woman such as herself, or does she see herself as unique, operating outside the female domain? I have listened carefully to Amma's healing rhetoric, personal narrative performances, and conversations for indications that she embraced and gave expression to an alternative model for the construction of female potentiality, a model her own position of authority would strengthen. I found myself hoping that she would view her position as one fulfilling the potential of her gender, not as an exception to it. Yet what I heard Amma most clearly articulate was a strong assertion of gender boundaries, and at the same time that her unique healing role is positioned outside the boundaries of her own gender.// Quotation marks removed from title to ensure alphabetical order

Multiscale Simulation of Thermocline Energy Storage for Concentrating Solar Power

Concentrating solar power (CSP) is a renewable and demonstrated technology for large-scale power generation but requires multiple engineering advancements to achieve grid parity with conventional fossil fuels. Part of this advancement includes novel and inexpensive thermal energy systems to decouple daily power production from intermittent solar collection. Dual-media thermocline tanks, composed of molten salt and solid rock filler, offer low-cost storage capability but the concept has experienced limited deployment in CSP plants due to unresolved concerns about long-term thermal and structural stability. The main objective of the present work is to advance the understanding of thermocline storage design and operation necessary for future commercial implementations. A multiscale numerical approach is conducted to investigate tank behavior at both a device level for comprehensive short-term analysis and at a system-level for reduced-order long-term analysis. A computational fluid dynamics (CFD) model is first developed to simulate molten-salt thermocline tanks in response to cyclic charge and discharge modes of operation. The model builds upon previous work in the literature with an expanded study of the internal solid filler size as well as added consideration for practical limits on tank height. Reducing the internal filler size improves thermal stratification inside the tank but decreases the bed permeability, resulting in a design tradeoff between storage performance and required pumping power. An effective rock diameter of 1 cm is found to be the most practical selection among the sizes considered. Also of interest is the structural stability of the thermocline tank wall in response to large temperature fluctuations associated with repeated charging and discharging. If sufficient hoop stress is generated from storage cycles, the tank becomes susceptible to failure via thermal ratcheting. The thermocline tank model is therefore extended to predict wall stress associated with operation and determine if ratcheting is expected to occur. Analysis is first performed with a multilayer structure to identify stable tank wall designs. Inclusion of internal thermal insulation between the porous bed and the steel wall is found to best prevent thermal ratcheting by decoupling the thermal response of the wall from the interior salt behavior. The structural modeling approach is then validated with a simulation of the 182 MWht thermocline tank installed at the historic Solar One power tower plant. The hoop stress predictions are found to show reasonable agreement with reported strain gage data along the tank wall and verify that the tank was not susceptible to ratcheting. The preceding use of commercial CFD software for thermocline tank simulation provides comprehensive solutions but the ease of application of this approach with respect to different operating scenarios is constrained by high computing costs. A new reduced-order model of energy transport inside a thermocline tank is therefore developed to provide thermal solutions at much lower computational cost. The storage model is first validated with past experimental data and then integrated into a system model of a 100 MWe molten-salt power tower plant, such that the thermocline tank is subjected to realistic solar collection and power production processes. Results from the system-level approach verify that a thermocline tank remains an effective and viable energy storage system over long-term operation within a CSP plant. The system-level analysis is then extended with an economic assessment of thermocline storage in a power tower plant. A parametric study of the plant solar multiple and thermocline tank size highlights suitable plant designs to minimize the levelized cost of electricity. Among the cases considered, a minimum levelized cost of 12.2 cent/kWhe is achieved, indicating that cost reductions outside of thermal energy storage remain necessary to obtain grid parity. As a sensible heat storage method, dual-media thermocline tanks remains subject to low energy densities and require large tank volumes. A possible design modification to reduce tank size is a substitution of the internal rock filler with an encapsulated phase-change material (PCM), which adds a high density latent heat storage mechanism to the tank assembly. The reduced-order thermocline tank model is first updated to include capsules of a hypothetical PCM and then reintegrated into the power tower plant system model. Implementation of a single PCM inside the tank does not yield significant energy storage gains because of an inherent tradeoff between the thermodynamic quality (i.e., melting temperature and heat of fusion) of the added latent heat and its utilization in storage operations. This problem may be circumvented with a cascaded filler structure composed of multiple PCMs with their melting temperatures tuned along the tank height. However, the benefit of a cascade structure is highly sensitive to appropriate selection of the PCM melting points relative to the thermocline tank operating temperatures

Economic Optimization of a Concentrating Solar Power Plant with Molten-salt Thermocline Storage

System-level simulation of a molten-salt thermocline tank is undertaken in response to year-long historical weather data and corresponding plant control. Such a simulation is enabled by combining a finite-volume model of the tank that includes a sufficiently faithful representation at low computation cost with a system-level power tower plant model. Annual plant performance of a 100 MWe molten-salt power tower plant is optimized as a function of the thermocline tank size and the plant solar multiple (SM). The effectiveness of the thermocline tank in storing and supplying hot molten salt to the power plant is found to exceed 99% over a year of operation, independent of tank size. The electrical output of the plant is characterized by its capacity factor (CF) over the year, which increases with solar multiple and thermocline tank size albeit with diminishing returns. The economic performance of the plant is characterized with a levelized cost of electricity (LCOE) metric. A previous study conducted by the authors applied a simplified cost metric for plant performance. The current study applies a more comprehensive financial approach and observes a minimum cost of 12.2 ¢/kWhe with a solar multiple of 3 and a thermocline tank storage capacity of 16 h. While the thermocline tank concept is viable and economically feasible, additional plant improvements beyond those pertaining to storage are necessary to achieve grid parity with fossil fuels