Simultaneous Measurement for Strain and Temperature Using Fiber Bragg Gratings and Multimode Fibers

An all-fiber sensor capable of simultaneous measurement of temperature and strain is newly presented. The sensing head is formed by a fiber Bragg grating combined with a section of multimode fiber that acts as a Mach-Zehnder interferometer for temperature and strain discrimination. The strain and temperature coefficients of multimode fibers vary with the core sizes and materials. This feature can be used to improve the strain and temperature resolution by suitably choosing the multimode fiber. For a 10 pm wavelength resolution, a resolution of 9.21 μ∈ in strain and 0.26°C in temperature can be achieved

Activation of peroxidic oxygen

Hydroperoxides are convenient rather mild oxidising agents. The aim of this work was to examine new ways of enhancing their oxidising power to provide the basis for a new peroxide-based oxidation system for application in industrial processes and an approach to a new low-temperature household bleaching system. The reactivity of alkyl hydroperoxides has been previously shown to be enhanced by geminal alkylation to give dialkyl peroxonium ions. This work examines the reaction of the cyclic bromohydroperoxides 5-bromocycloocten-l-yl hydroperoxide, 6-bromocycloocten-1-yl hydroperoxide and 5-bromocyclohepten-l-yl hydroperoxide with silver trifluoroacetate to form dialkyl peroxonium ions. These hydroperoxides were readily prepared from their parent alkenes by singlet oxygenation. Formation of the expected bicyclic ethers from these hydroperoxides with concomitant oxidation of phenyl methyl sulphoxide provides evidence for the intermediacy of the dialkyl peroxonium ion in these cases. The synthesis of ortho halomethyl benzyl hydroperoxides by homolytic and heterolytic methods was examined the aim here was the preparation of an ortho halomethyl substituted cumene hydroperoxide. This work led to a synthesis of the hydroperoxide 2-bromomethyl alpha methoxy benzyl hydroperoxide by ozonlysis. The reaction of this hydroperoxide with silver salts was examined. We presumed that the principles relied upon to activate hydroperoxides could be further extended to the activation of a peroxyacid by preparation of precursors capable of forming an acyl alkyl peroxonium ion and ortho halomethyl substituted benzoic acids and their related peresters were prepared. The results of this study suggest that intramolecular ring closure to form an acyl alkyl peroxonium ion is a disfavoured process compared to intermolecular substitution in this type of system

Core-Offset Small-Core-Diameter Dispersion Compensation Fiber Interferometer and its Applications in Fiber Sensors

We propose a core-offset small core diameter dispersion compensation fiber (DCF) interferometer and investigate its applications in fiber sensors. If the transverse force is applied to a short section of the DCF, there is almost no crosstalk on the transmission spectrum between the extinction ratio variation induced by the transverse force and the wavelength shift caused by the longitudinal strain or ambient temperature, which can be applied to measure both transverse and longitudinal strain, or both transverse strain and temperature, simultaneously. The proposed sensors have the advantages of low cost, simple and compact structure, and good reproducibility

Temperature- and Phase-Independent Lateral Force Sensor based on a Core-Offset Multi-Mode Fiber Interferometer

A novel lateral force sensor based on a core-offset multi-mode fiber (MMF) interferometer is reported. High extinction ratio can be obtained by misaligning a fused cross section between the single-mode fiber (SMF) and MMF. With the variation of the lateral force applied to a short section of the MMF, the extinction ratio changes while the interference phase remains almost constant. The change of the extinction ratio is independent of temperature variations. The proposed force sensor has the advantages of temperature- and phase-independency, high extinction ratio sensitivity, good repeatability, low cost, and simple structure. Moreover, the core-offset MMF interferometer is expected to have applications in fiber filters and tunable phase-independent attenuators

The Emergency Room Admission: How Far Does the Open Door Go?

In recent years many private and some public hospitals have assumed a new proprietary persona, a business-like posture that clashes with the traditional hospital goals of charity and community service. This conflict may be most acute in the emergency room where the hospital may further its financial interests by quickly transferring or discharging undesirable emergency patients. This article explores the extent of a private hospital’s legal obligation to treat a patient once emergency care has begun. It begins by looking at hospital revolutions, emergency rooms, and the standards of emergency care. It then explores the common law and “no duty” rule, the open door policy, the duty to continue emergency care, and the standard of conduct

Control Communication Complexity of Distributed Actions

Recent papers have treated {\em control communication complexity} in the context of information-based, multiple agent control systems including nonlinear systems of the type that have been studied in connection with quantum information processing. The present paper continues this line of investigation into a class of two-agent distributed control systems in which the agents cooperate in order to realize common goals that are determined via independent actions undertaken individually by the agents. A basic assumption is that the actions taken are unknown in advance to the other agent. These goals can be conveniently summarized in the form of a {\em target matrix}, whose entries are computed by the control system responding to the choices of inputs made by the two agents. We show how to realize such target matrices for a broad class of systems that possess an input-output mapping that is bilinear. One can classify control-communication strategies, known as {\em control protocols}, according to the amount of information sharing occurring between the two agents. Protocols that assume no information sharing on the inputs that each agent selects and protocols that allow sufficient information sharing for identifying the common goals are the two extreme cases. Control protocols will also be evaluated and compared in terms of cost functionals given by integrated quadratic functions of the control inputs. The minimal control cost of the two classes of control protocols are analyzed and compared. The difference in the control costs between the two classes reflects an inherent trade-off between communication complexity and control cost.Comment: 34 pages, 1 figure, To appear in the IEEE Trans. Automatic Contro

Computational Aspects of Optional P\'{o}lya Tree

Optional P\'{o}lya Tree (OPT) is a flexible non-parametric Bayesian model for density estimation. Despite its merits, the computation for OPT inference is challenging. In this paper we present time complexity analysis for OPT inference and propose two algorithmic improvements. The first improvement, named Limited-Lookahead Optional P\'{o}lya Tree (LL-OPT), aims at greatly accelerate the computation for OPT inference. The second improvement modifies the output of OPT or LL-OPT and produces a continuous piecewise linear density estimate. We demonstrate the performance of these two improvements using simulations

Toxicity of Carbon Nanotubes and its Implications for Occupational and Environmental Health

This viewgraph document reviews the sources of Nano particles in the environment, the structure and properties of Carbon Nanotubes (CNTs), the physical characteristics of CNT materials, pulmonary and other health concerns of exposure to CNTs. The toxicity of CNT in rodents is summarized and some natural, and man-made sources of CNTs are shown. CNTs are electrically and thermally conductive, fibrous, biopersistent and very complicated in structures. The factors affecting toxicity of CNTs are more than size and surface area

Pulmonary Toxicity Studies of Lunar Dust in Rodents

NASA has been contemplating returning astronauts to the moon for long-duration habitation and research and using it as a stepping-stone to Mars. Other spacefaring nations are planning to send humans to the moon for the first time. The surface of the moon is covered by a layer of fine dust. Fine terrestrial dusts, if inhaled, are known to pose a health risk to humans. Some Apollo crews briefly exposed to moon dust that adhered to spacesuits and became airborne in the Lunar Module reported eye and throat irritation. The habitable area of any lunar landing vehicle or outpost would inevitably become contaminated with lunar dust. To assess the health risks of exposure of humans to airborne lunar dust, we evaluated the toxicity of Apollo 14 moon dust in animal lungs. Studies of the pulmonary toxicity of a dust are generally first done by intratracheal instillation (ITI) of aqueous suspensions of the test dust into the lungs of rodents. If a test dust is irritating or cytotoxic to the lungs, the alveolar macrophages, after phagocytizing the dust particles, will release cellular messengers to recruit white blood cells (WBCs) and to induce dilation of blood capillary walls to make them porous, allowing the WBCs to gain access to the alveolar space. The dilation of capillary walls also allows serum proteins and water entering the lung. Besides altering capillary integrity, a toxic dust can also directly kill the cells that come into contact with it or ingest it, after which the dead cells would release their contents, including lactate dehydrogenase (a common enzyme marker of cell death or tissue damage). In the treated animals, we lavaged the lungs 1 and 4 weeks after the dust instillation and measured the concentrations of these biomarkers of toxicity in the bronchioalveolar lavage fluids to determine the toxicity of the dust. To assess whether the inflammation and cellular injury observed in the biomarker study would lead to persistent or progressive histopathological changes, a similar study was conducted to microscopically examine rat lung tissue and the associated lymph nodes for lesions, including fibrosis, 1 or 3 months after the instillation. The results from this ITI study led us to select two concentrations (20 and 60 mg/cu m) for an inhalation study, in which rats were exposed to lunar dust 6 h daily for 4 weeks (5d/wk). Similar biochemical and histopathological assessments were carried out in these rats 1 day or 1, 4, or 13 weeks after the dust exposure. Rats exposed to lunar dust by ITI or inhalation showed effects indicating that the dust is moderately toxic. The data will be useful to establish safe exposure limits for astronauts working in a lunar habitat and also help engineers designing dust mitigation systems for lunar vehicles and habitats

Dry Powder Deposition and Compaction for Functionally Graded Ceramics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65992/1/j.1551-2916.2006.01272.x.pd