Seismic Stability Analysis of a High Earth and Rockfill Dam

Accumulation of knowledge on earthquake activity in California has lead to stronger ground motions being postulated for the evaluation of the seismic stability of dams. A recent regional seismicity study for a 555 ft high earth and rockfill dam in central California lead to a ground motion with peak ground acceleration (PGA) of 0.50g originating in a local fault system 3 miles from the dam site. This PGA is more than 6 times higher than the PGA=0.08g value originally adopted when the Dam was analyzed for seismic stability 20 years ago. Thus, as part of FERC Part 12 evaluation requirements, the seismic stability of the Dam was re-evaluated using the updated ground motion and state-of-the-practice technology. This paper presents the analysis procedures and the results

Modelling of Phase Transforming Cellular Material (PXCM)

Phase transforming cellular materials (PXCMs) are a new class of materials that can go through large deformation and return to their original configuration. Currently, there are reliable cellular materials that can resist large deformation, for example, honey comb; however, when these materials are compared to PXCMs, they cannot stay in their elastic range. The biggest advantage about PXCMs is that they are not only inexpensive materials, but they are also highly-durable and they absorb and dissipate high amounts of energy. The main concept behind PXCMs is that they contain unit cells that have stable configurations. Each stable configuration of the unit cell corresponds to a phase. The transition between these phases are interpreted as phase-transformation of the cellular material. Our approach to this project is to create a simulation tool that will predict the mechanical behavior of a PXCM. The tool will have a GUI interface where users can input the information of the unit cell of the PXCMs that they want to model. When the tool is executed, the simulation will present a graph representative of the output. The output displays phases and stable configuration of the material in a force vs displacement graph of a M rows by N columns of PXCMs. The purpose of this interactive tool is to serve as a visual aid for users who want to learn more about PXCMs and also create more complex and sophisticated PXCMs designs. Successful implementation of this tool will contribute positively in creating design guidelines for a new PXCM with improved energy absorption and dissipation

Visual Assessment of Soil Structure as an Early Indicator of Soil Quality in Response to Intensive Rotational Grazing

Grasslands can play a crucial role in mitigation of global warming by serving as carbon sink. Nevertheless, to achieve the grasslands’ potential, sustainable management is of the utmost importance as it determines system’s productivity and ecosystem services. Due to the increasing demand for animal products in developing countries, grazed areas increase exponentially in the tropics, mainly due to unsustainable management leading to low productivity and soil degradation. We evaluated the impact of intensive rotational grazing management (IRG) on early indicators of soil quality following land-use change based on on-farm observations of visual soil characteristics using two different widely used assessment methods: visual soil assessment-VSA and visual evaluation of soil structure-VESS. Correlation of visual methods were combined with measurements of soil macrofauna abundance and physical properties (e.g. bulk density, soil porosity). The IRG established in two study sites in Colombia was compared with traditional long-term continuous grazing with low stocking rate (1 LU ha-1). The IRG was based on rapid (1 day) cattle grazing in paddocks with high stocking rate (180 LU ha-1) followed by 60 days of recovery. In both study sites, IRG increased considerably total stocking rate to 4 LU ha-1 while improving grassland composition by enabling more valuable species, which contributed to soil quality and increased grassland productivity. Both VSA and VESS discriminated IRG-managed sites in less than one year after IRG adoption. Our results demonstrate that visual soil assessment is a useful mean for evaluation of soil quality and grassland productivity. Furthermore, VSA and VESS seemed to be more suitable in discriminating among management in early stages, when compared to commonly used soil physical properties, and were strongly correlated mainly to the abundance of earthworms. Furthermore, our study confirms the importance of grazing management in soil quality and ecosystem productivity/sustainability

Mental disorders in primary health care: a study of their frequency and diagnosis in four developing countries

1624 patients who were attending primary health facilities in 4 developing countries were examined to determine how many were suffering from mental disorder. Using stringent criteria to establish the presence of psychiatric morbidity, 225 cases were found, indicating an overall frequency of 13·9 %. The great majority of cases were suffering from neurotic illnesses and for most the presenting complaint was of a physical symptom, such as headache, abdominal pain, cough or weakness. The health workers following their normal procedure correctly detected one third of the psychiatric case

Effect of Sr, Mg and Fe substitution on the physico-chemical and biological properties of Si Ca P multilayer scaffolds

In this work, a new combination of ceramic materials is proposed for bone tissue engi neering applications. Multilayer scaffolds consisting of a core composed mainly of calcium pyrophosphate and external coatings of silica and calcium doped with Fe3+, Sr2+ and Mg2+ were prepared. To study the influence of the arrangement of dopant ions in the external coatings, two different scaffolds were developed: scaffolds 3J consisting of a single exter nal coating with 9mol% of Fe3+, Sr2+ and Mg2+ ions; and scaffolds 3S comprising three external coatings, each containing 3mol% of Fe3+, Sr2+ and Mg2+ ions. Scaffolds were physico chemically characterized and evaluated for in vitro bioactivity and cellular response in the presence of MG-63 cells. The results showed that the core scaffold displayed no in vitro bioac tivity or good cellular response, but served as a support for the external coatings given its mechanical resistance. The cell viability of scaffolds 3J and 3S increased more than 100% in relation to the core, and also improved cell proliferation and adhesion resulting in a dense layer of cells that covered the scaffolds’ entire surface. The arrangement of ions in the external coatings did not influence the cellular response, but determined the bioactivity rateNayarit A. Mata was funded by a grant from the Generalitat Valenciana with reference GRISOLIAP/2018/037 and pre-doctoral mobility co-financed by the European Social Fund and the Generalitat Valenciana with reference BEFPI/2021/056. TThis publication is part of the Grant PID2020- 116693RB-C21 funded by MCIN/AEI/10.13039/501100011033

Entanglement and Timing-Based Mechanisms in the Coherent Control of Scattering Processes

The coherent control of scattering processes is considered, with electron impact dissociation of H$_2^+$ used as an example. The physical mechanism underlying coherently controlled stationary state scattering is exposed by analyzing a control scenario that relies on previously established entanglement requirements between the scattering partners. Specifically, initial state entanglement assures that all collisions in the scattering volume yield the desirable scattering configuration. Scattering is controlled by preparing the particular internal state wave function that leads to the favored collisional configuration in the collision volume. This insight allows coherent control to be extended to the case of time-dependent scattering. Specifically, we identify reactive scattering scenarios using incident wave packets of translational motion where coherent control is operational and initial state entanglement is unnecessary. Both the stationary and time-dependent scenarios incorporate extended coherence features, making them physically distinct. From a theoretical point of view, this work represents a large step forward in the qualitative understanding of coherently controlled reactive scattering. From an experimental viewpoint, it offers an alternative to entanglement-based control schemes. However, both methods present significant challenges to existing experimental technologies

International flow of Zambian nurses

This commentary paper highlights changing patterns of outward migration of Zambian nurses. The aim is to discuss these pattern changes in the light of policy developments in Zambia and in receiving countries