Lepidobatrachus laevis

Number of Pages: 16Integrative BiologyGeological Science

Changes of instability thresholds of rotor due to bearing misalignments

The influence of bearing misalignment upon the dynamic characteristics of statistically indeterminant rotor bearing systems is investigated. Both bearing loads and stability speed limits of a rotor may be changed significantly by magnitude and direction of bearing misalignment. The useful theory of short journal bearings is introduced and simple analytical expressions, governing the misalignment problem, are carried out. Polar plots for the bearing load capacities and stability maps, describing the speed limit in terms of misalignment, are presented. These plots can be used by the designer to estimate deviations between calculation and experimental data due to misalignment effects

Sound Mode Hydrodynamics from Bulk Scalar Fields

We study the hydrodynamic sound mode using gauge/gravity correspondence by examining a generic black brane background's response to perturbations. We assume that the background is generated by a single scalar field, and then generalize to the case of multiple scalar fields. The relevant differential equations obeyed by the gauge invariant variables are presented in both cases. Finally, we present an analytical solution to these equations in a special case; this solution allows us to determine the speed of sound and bulk viscosity for certain special metrics. These results may be useful in determining sound mode transport coefficients in phenomenologically motivated holographic models of strongly coupled systems.Comment: 17 pages. Corrections made to one of the gauge invariant equations (66). This equation was not used in the other main conclusions of the paper, so the rest of the results are unchange

Noiseless Quantum Circuits for the Peres Separability Criterion

In this Letter we give a method for constructing sets of simple circuits that can determine the spectrum of a partially transposed density matrix, without requiring either a tomographically complete POVM or the addition of noise to make the spectrum non-negative. These circuits depend only on the dimension of the Hilbert space and are otherwise independent of the state.Comment: 4 pages RevTeX, 7 figures encapsulated postscript. v5: title changed slightly, more-or-less equivalent to the published versio

Assessing Household Drinking Water Needs: Reaching Many One Water Filter at a Time in Los Robles, Nicaragua

Water quality and water scarcity have dominated international health and environmental management initiatives for decades because of the devastating impacts poor water quality has on child mortality and general public well-being, particularly in developing countries. Non-profit organizations, private utilities, and government agencies have invested significant financial resources and time to increase access to improved water sources in low-income countries. However, the sustainability of water improvement project benefits have been disappointing due to a lack of community and household capacity to operate and maintain introduced water systems. This paper evaluates a community/household based water improvement project introduced by a small non-governmental organization, Proyecto Nica Agua, in Los Robles, Nicaragua. The project sought to build local community capacity to develop and sustain a water improvement project based on individual household use of ceramic water filters, hygiene and sanitation education, community service projects and watershed education. Household health surveys, informal interviews, water quality sampling, and on-site observations were used to evaluate the effectiveness and potential sustainability of the introduced water system. The introduction of ceramic water filters resulted in a 90% reduction in reported cases of diarrhea since the beginning of the project 2011. This study found that reported cases of water-related illnesses (i.e., diarrhea, parasites and kidney infections) were eliminated after two years of filter use (n=20 households). In a survey of village residents, 78% of respondents (n=201 households) indicated a willingness to maintain their water filters, while 82% reported they would participate in another community service project as a means to maintain or replace water filters. Escherichia coli was present in 90% of water filter samples, however the accuracy of the tests cannot be confirmed. In informal interviews 74% reported not knowing the origin of contamination in the water supply. The results of this study were used to develop a watershed education curriculum to provide information about the effects of human activities on both surface and groundwater supplies. The curriculum is currently being used in Los Robles and in other regions of Nicaragua where Proyecto Nica Agua has extended their project

Assessing Environmental Impact of the Built Environment by Adopting Life Cycle Design: Using Swanton Pacific Ranch as a Case Study

To combat the carbon emissions contributed to the atmosphere by the built environment, it is imperative that low-embodied-carbon materials choices be prioritized throughout the building design process. To achieve this, this professional project creates an Excel-based, open source, and user-friendly tool for the construction sector to make design decisions that prioritize the sustainability of structures, as one such tool does not currently exist. The use of OpenLCA software and the EcoInvent34 database are utilized to calculate the environmental impact of 25 different building materials, as well as energy and electricity consumption. Swanton Pacific Ranch (SPR) in Santa Cruz County is utilized as a case study site. This is accomplished through the comparison of two hypothetical structures to test the validity and user-friendliness of the excel-based tool, and make edits and improvements as needed based on feedback. From this process, the benefits of the tool, as well as areas for its continued improvement are discussed

Numerical simulation of the flow and fuel-air mixing in an axisymmetric piston-cylinder arrangement

The implicit factored method of Beam and Warming was employed to describe the flow and the fuel-air mixing in an axisymmetric piston-cylinder configuration during the intake and compression strokes. The governing equations were established on the basis of laminar flow. The increased mixing due to turbulence was simulated by appropriately chosen effective transport properties. Calculations were performed for single-component gases and for two-component gases and for two-component gas mixtures. The flow field was calculated as functions of time and position for different geometries, piston speeds, intake-charge-to-residual-gas-pressure ratios, and species mass fractions of the intake charge. Results are presented in graphical form which show the formation, growth, and break-up of those vortices which form during the intake stroke and the mixing of fuel and air throughout the intake and compression strokes. It is shown that at bore-to-stroke ratio of less than unity, the vortices may break-up during the intake stroke. It is also shown that vortices which do not break-up during the intake stroke coalesce during the compression stroke. The results generated were compared to existing numerical solutions and to available experimental data

Vortex motion in axisymmetric piston-cylinder configurations

By using the Beam and Warming implicit-factored method of solution of the Navier-Stokes equations, velocities were calculated inside axisymmetric piston cylinder configurations during the intake and compression strokes. Results are presented in graphical form which show the formation, growth and breakup of those vortices which form during the intake stroke by the jet issuing from the valve. It is shown that at bore-to-stroke ratio of less than unity, the vortices may breakup during the intake stroke. It is also shown that vortices which do not breakup during the intake stroke coalesce during the compression stroke

Uneven Bulgarian Rhythms Explained by Covid-19 Related Vocabulary

This is a chart of uneven Bulgarian rhythms correlated with COVID-related words. Behind the rhythm chart in the photo is a 1980’s map of Bulgaria with ethnographic regions of the country written on it.This is a chart of uneven Bulgarian rhythms correlated with COVID-related words. Behind the rhythm chart in the photo is a 1980’s map of Bulgaria with ethnographic regions of the country written on it.This is a chart of uneven Bulgarian rhythms correlated with COVID-related words. Behind the rhythm chart in the photo is a 1980’s map of Bulgaria with ethnographic regions of the country written on it.This is a chart of uneven Bulgarian rhythms correlated with COVID-related words. Behind the rhythm chart in the photo is a 1980’s map of Bulgaria with ethnographic regions of the country written on it

A shear spectral sum rule in a non-conformal gravity dual

A sum rule which relates a stress-energy tensor correlator to thermodynamic functions is examined within the context of a simple non-conformal gravity dual. Such a sum rule was previously derived using AdS/CFT for conformal $\mathcal{N} = 4$ Supersymmetric Yang-Mills theory, but we show that it does not generalize to the non-conformal theory under consideration. We provide a generalized sum rule and numerically verify its validity. A useful byproduct of the calculation is the computation of the spectral density in a strongly coupled non-conformal theory. Qualitative features of the spectral densities and implications for lattice measurements of transport coefficients are discussed.Comment: 13 pages, 3 figures. v5: Typos in Eq. (60) fixed. v4: References added, matches published version. v3: Minor typographical corrections. v2: References and some discussion in Appendix A have been added; conclusions unchange