The noise and flow characteristics of inverted-profile coannular jets

A basic understanding of the noise reduction mechanisms in shock-free inverted-velocity-profile coannular jets was studied. Acoustic measurements are first conducted in an anechoic facility to isolate the effects of inverted velocity and inverted temperature for coannular jets having constant total thrust, mass flow rate and exit area. To obtain physical explanations of the measured noise changes, several types of experiments are conducted. These include (1) source location experiments using the polar correlation technique, (2) mean flow surveys using a combination pressure/temperature probe, and (3) detailed mean flow and turbulence measurements using a two-point four-channel laser velocimeter. The results from these experiments are presented and discussed in detail. Finally, the measured variations of coannular jet mixing noise with fan-to-primary velocity ratio and static temperature ratio are interpreted by utilizing the results from the various experimental phases in conjunction with the existing Lockheed single jet noise prediction model

Non-equilibrium fluctuations and mechanochemical couplings of a molecular motor

We investigate theoretically the violations of Einstein and Onsager relations, and the efficiency for a single processive motor operating far from equilibrium using an extension of the two-state model introduced by Kafri {\em et al.} [Biophys. J. {\bf 86}, 3373 (2004)]. With the aid of the Fluctuation Theorem, we analyze the general features of these violations and this efficiency and link them to mechanochemical couplings of motors. In particular, an analysis of the experimental data of kinesin using our framework leads to interesting predictions that may serve as a guide for future experiments.Comment: 4 pages, 4 figures, accepted to Phys. Rev. Let

Novel Precursors for Boron Nanotubes: The Competition of Two-Center and Three-Center Bonding in Boron Sheets

We present a new class of boron sheets, composed of triangular and hexagonal motifs, that are more stable than structures considered to date and thus are likely to be the precursors of boron nanotubes. We describe a simple and clear picture of electronic bonding in boron sheets and highlight the importance of three-center bonding and its competition with two-center bonding, which can also explain the stability of recently discovered boron fullerenes. Our findings call for reconsideration of the literature on boron sheets, nanotubes, and clusters.Comment: 4 pages, 4 figures, 1 tabl

Advanced ceramic coating development for industrial/utility gas turbine applications

The effects of ceramic coatings on the lifetimes of metal turbine components and on the performance of a utility turbine, as well as of the turbine operational cycle on the ceramic coatings were determined. When operating the turbine under conditions of constant cooling flow, the first row blades run 55K cooler, and as a result, have 10 times the creep rupture life, 10 times the low cycle fatigue life and twice the corrosion life with only slight decreases in both specific power and efficiency. When operating the turbine at constant metal temperature and reduced cooling flow, both specific power and efficiency increases, with no change in component lifetime. The most severe thermal transient of the turbine causes the coating bond stresses to approach 60% of the bond strengths. Ceramic coating failures was studied. Analytic models based on fracture mechanics theories, combined with measured properties quantitatively assessed both single and multiple thermal cycle failures which allowed the prediction of coating lifetime. Qualitative models for corrosion failures are also presented

Antimony doping of Si layers grown by solid-phase epitaxy

We report here that layers of Si formed by solid-phase epitaxial growth (SPEG) can be doped intentionally. The sample consists initially of an upper layer of amorphous Si (~1 µm thick), a very thin intermediate layer of Sb (nominally 5 Å), and a thin lower layer of Pd (~500 Å), all electron-gun deposited on top of a single-crystal substrate (1–10 Ω cm, p type, orientation). After a heating cycle which induces epitaxial growth, electrically active Sb atoms are incorporated into the SPEG layer, as shown by the following facts: (a) the SPEG layer forms a p-n junction against the p-type substrate, (b) the Hall effect indicates strong n-type conduction of the layer, and (c) Auger electron spectra reveal the presence of Sb in the layer

Oral Feeding Assessment Predicts Length of Hospital Stay in Late Preterm Infants

BACKGROUND: When compared with term infants, late preterm (LP) infants have greater morbidity and mortality, longer hospital stay, and greater rate of hospital readmission. Oral feeding difficulty is one of the prominent reasons for delayed discharge in LP infants. OBJECTIVE: To identify the maturity levels of LP infants\u27 oral feeding skills (OFS) at the time of their first oral feeding and to determine the relationship between OFS maturity levels and length of hospital stay. METHODS: OFS was assessed in 48 LP infants born between 340/7 and 356/7 weeks gestational age at the time of their first oral feeding within 24 h of birth. The intake at 5 minutes, at completion of the feeding, and the duration of feeding a 15 mL prescribed volume of milk were tabulated. Proficiency expressed as percent mL consumed in the first 5 min/15 mL prescribed and rate of milk transfer over the entire feeding (mL/min) were recorded. OFS were assessed using a novel 4-level scale defined by the combined proficiency and rate of milk transfer. RESULTS: When compared with their 35-week counterparts, infants born at 34 weeks gestation had poorer OFS profiles (p = 0.035) and longer hospital stay (p \u3c 0.001). Additionally, further analyses demonstrated that, independently, LOS was associated negatively with both GA and OFS. CONCLUSION: Assessment of OFS levels in LP infants at their first oral feeding can help identify infants at risk of oral feeding issues that may delay hospital discharge. For those infants, we speculate that provision of evidence-based efficacious interventions that improve OFS may shorten hospital stay and decrease hospital re-admissions

Trust and Risk Relationship Analysis on a Workflow Basis: A Use Case

Trust and risk are often seen in proportion to each other; as such, high trust may induce low risk and vice versa. However, recent research argues that trust and risk relationship is implicit rather than proportional. Considering that trust and risk are implicit, this paper proposes for the first time a novel approach to view trust and risk on a basis of a W3C PROV provenance data model applied in a healthcare domain. We argue that high trust in healthcare domain can be placed in data despite of its high risk, and low trust data can have low risk depending on data quality attributes and its provenance. This is demonstrated by our trust and risk models applied to the BII case study data. The proposed theoretical approach first calculates risk values at each workflow step considering PROV concepts and second, aggregates the final risk score for the whole provenance chain. Different from risk model, trust of a workflow is derived by applying DS/AHP method. The results prove our assumption that trust and risk relationship is implicit

Domestic Value Added and Employment Generated by Chinese Exports: A Quantitative Estimation

We develop an input-output methodology to estimate how Chinese exports affect the country’s total domestic value added (DVA) and employment for 1995 and 2002. Total DVA generated by exports is obtained by subtracting all direct and indirect imported intermediate goods from the gross value of exports, and total employment is obtained by adding all direct and indirect employment generated by exports. To implement these estimations, we use hitherto unpublished Chinese government data to construct several completely new datasets, including an input-output table with separate input-output and employment-output coefficients for processing and non-processing exports. In 2002 (1995), for every US$1,000 dollar of Chinese exports, DVA and employment are estimated to be US$466 (US$545) and 0.242 (0.375) person-year, respectively.Input-output tables, Chinese exports, employment, domestic value added

Generalised dimensions of measures on almost self-affine sets

We establish a generic formula for the generalised q-dimensions of measures supported by almost self-affine sets, for all q>1. These q-dimensions may exhibit phase transitions as q varies. We first consider general measures and then specialise to Bernoulli and Gibbs measures. Our method involves estimating expectations of moment expressions in terms of `multienergy' integrals which we then bound using induction on families of trees