Experimental pressure drop investigation of wetting and nonwetting mercury condensing in uniformly tapered tubes

Pressure drop of wetting and nonwetting mercury condensing in tapered tubes - turbogenerator system

Persistent Chaos in High Dimensions

An extensive statistical survey of universal approximators shows that as the dimension of a typical dissipative dynamical system is increased, the number of positive Lyapunov exponents increases monotonically and the number of parameter windows with periodic behavior decreases. A subset of parameter space remains in which topological change induced by small parameter variation is very common. It turns out, however, that if the system's dimension is sufficiently high, this inevitable, and expected, topological change is never catastrophic, in the sense chaotic behavior is preserved. One concludes that deterministic chaos is persistent in high dimensions.Comment: 4 pages, 3 figures; Changes in response to referee comment

Location choice for renewable resource extraction with multiple non-cooperative extractors: a spatial Nash equilibrium model and numerical implementation

Especially in lower-income countries, the distribution of renewable resources in open access settings often reflects the non-cooperative spatial extraction decisions of many individuals who spread out across a landscape. These individuals recognize tradeoffs between distance to the resource, density, and competition amongst extractors. In this paper we present a game theoretic model that explicitly accommodates such explicitly spatial non-cooperative behavior with respect to the extraction of a stationary renewable natural resource, such as a non-timber forest products or bivalvia (for example, oysters, clams), that is located in a two dimensional landscape. Villagers that have identical labor allocations and preferences are shown to undertake very different extraction pathways in equilibrium. For example, some may extract in more congested patches closer to the village while others may extract in less crowded but more distant patches. For many parameterizations, we find multiple spatial Nash equilibria that differ with respect to the number of villagers at each resource location, whether individual villagers extract from one or multiple locations, and the extent and spatial pattern of resource degradation. In addition to finding equilibria with widely different actions taken by identical extractors, the analysis here demonstrates the impact of simplifying assumptions for spatial decisions on predictions of policy impact, resource distributions, and conflict

High-speed Civil Transport Aircraft Emissions

Estimates are given for the emissions from a proposed high speed civil transport (HSCT). This advanced technology supersonic aircraft would fly in the lower stratosphere at a speed of roughly Mach 1.6 to 3.2 (470 to 950 m/sec or 920 to 1850 knots). Because it would fly in the stratosphere at an altitude in the range of 15 to 23 km commensurate with its design speed, its exhaust effluents could perturb the chemical balance in the upper atmosphere. The first step in determining the nature and magnitude of any chemical changes in the atmosphere resulting from these proposed aircraft is to identify and quantify the chemically important species they emit. Relevant earlier work is summarized, dating back to the Climatic Impact Assessment Program of the early 1970s and current propulsion research efforts. Estimates are provided of the chemical composition of an HSCT's exhaust, and these emission indices are presented. Other aircraft emissions that are not due to combustion processes are also summarized; these emissions are found to be much smaller than the exhaust emissions. Future advances in propulsion technology, in experimental measurement techniques, and in understanding upper atmospheric chemistry may affect these estimates of the amounts of trace exhaust species or their relative importance

In memorium: Jasper Daube MD

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156241/2/mus26916_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156241/1/mus26916.pd

Allocating group-level payments for ecosystem services: experiences from a REDD+ pilot in Tanzania

Payments for ecosystem services (PES) typically reward landowners for managing their land to provide ecosystem services that would not otherwise be provided. REDD+—Reduced Emissions from Deforestation and Forest Degradation—is a form of PES aimed at decreasing carbon emissions from forest conversion and extraction in lower-income countries. A key challenge for REDD+ occurs when it is implemented at a group, rather than an individual landowner, level. Whilst achieving a group-level reduction relies on individuals changing their interaction with the forest, incentives are not aligned explicitly at the individual level. Rather, payments are made to a defined group as a single entity in exchange for verified reduced forest loss, as per a PES scheme. In this paper, we explore how REDD+ has been implemented in one multiple-village pilot in Tanzania with the village defining the group. Our findings suggest that considerable attention has been paid towards monitoring, reporting, verification (MRV), and equity. No explicit mechanism ensures individual compliance with the village-level PES, and few villages allocate funds for explicit enforcement efforts to protect the forest from illegal activities undertaken by individual group members or by outsiders. However, the development of village-level institutions, “social fencing,” and a shared future through equal REDD+ payments, factor into decisions that influence the level of compliance at the village level that the program will eventually achieve

An analytical stability theory for Faraday waves and the observation of the harmonic surface response

We present an analytical stability theory for the onset of the Faraday instability, applying over a wide frequency range between shallow water gravity and deep water capillary waves. For sufficiently thin fluid layers the surface is predicted to occur in harmonic rather than subharmonic resonance with the forcing. An experimental confirmation of this result is given. PACS: 47.20.Ma, 47.20.Gv, 47.15.CbComment: 10 pages (LaTeX-file), 3 figures (Postscript) Submitted for publicatio

Understanding the complex phase diagram of uranium: the role of electron-phonon coupling

We report an experimental determination of the dispersion of the soft phonon mode along [1,0,0] in uranium as a function of pressure. The energies of these phonons increase rapidly, with conventional behavior found by 20 GPa, as predicted by recent theory. New calculations demonstrate the strong pressure (and momentum) dependence of the electron-phonon coupling, whereas the Fermi-surface nesting is surprisingly independent of pressure. This allows a full understanding of the complex phase diagram of uranium, and the interplay between the charge-density wave and superconductivity

Global surfaces of section in the planar restricted 3-body problem

The restricted planar three-body problem has a rich history, yet many unanswered questions still remain. In the present paper we prove the existence of a global surface of section near the smaller body in a new range of energies and mass ratios for which the Hill's region still has three connected components. The approach relies on recent global methods in symplectic geometry and contrasts sharply with the perturbative methods used until now.Comment: 11 pages, 1 figur

Effect of antifungal agents on indwelling voice prosthetic biofilms

Rehabilitating the lost voice of laryngectomy patients by insertion of a silicone rubber voice prosthesis is now generally considered to be superior to any other form of substitute voice production. However, a drawback of these implants is the rapid colonization by a mixed biofilm of bacteria and yeasts, mainly Candida species, leading to failure and frequent exchange of the implant. A strategy frequently applied by otolaryngologists is oropharyngeal yeast decontamination by using antifungal agents, despite the fact that there is no compelling evidence that prescription of antifungal agents will prolong the lifetime of voice prostheses. Moreover, the prophylactic use of antifungal agents contributes to the development of resistant strains. Alternative approaches to prolonging the lifetime of silicone rubber voice prostheses may be found in modification of the silicone rubber surface of the implant, diet supplementation with active, probiotic bacteria, or salivary substitutes with synthetic antimicrobial peptides.</p