Dynamics of polymer chain collapse into compact states

Molecular dynamics simulation methods are used to study the folding of polymer chains into packed cubic states. The polymer model, based on a chain of linked sites moving in the continuum, includes both excluded volume and torsional interactions. Different native-state packing arrangements and chain lengths are explored; the organization of the native state is found to affect both the ability of the chain to fold successfully and the nature of the folding pathway as the system is gradually cooled. An order parameter based on contact counts is used to provide information about the folding process, with contacts additionally classified according to criteria such as core and surface sites or local and distant site pairs. Fully detailed contact maps and their evolution are also examined.Comment: 11 pages, 11 figures (some low resolution

Lepton Flavour Violation in a Class of Lopsided SO(10) Models

A class of predictive SO(10) grand unified theories with highly asymmetric mass matrices, known as lopsided textures, has been developed to accommodate the observed mixing in the neutrino sector. The model class effectively determines the rate for charged lepton flavour violation, and in particular the branching ratio for $\mu -> e \gamma$, assuming that the supersymmetric GUT breaks directly to the constrained minimal supersymmetric standard model (CMSSM). We find that in light of the combined constraints on the CMSSM parameters from direct searches and from the WMAP satellite observations, the resulting predicted rate for $\mu -> e \gamma$ in this model class can be within the current experimental bounds for low $\tan \beta$, but that the next generation of $\mu -> e \gamma$ experiments would effectively rule out this model class if LFV is not detected.Comment: 23 page

Modeling of droplet generation in a top blowing steelmaking process

Quantification of metal droplets ejected due to impinging gas jet on the surface of liquid metal is an important parameter for the understanding and for the modeling of the refining kinetics of reactions in slag-metal emulsion zone. In the present work, a numerical study has been carried out to critically examine the applicability of droplet generation rate correlation previously proposed by Subagyo et al. on the basis of dimensionless blowing number (N B). The blowing number was re-evaluated at the impingement point of jet with taking into account the temperature effect of change in density and velocity of the gas jet. The result obtained from the work shows that the modified blowing number N B,T at the furnace temperature of 1873 K (1600 °C) is approximately double in magnitude compared to N B calculated by Subagyo and co-workers. When N B,T has been employed to the Subagyo’s empirical correlation for droplet generation, a wide mismatch is observed between the experimental data obtained from cold model and hot model experiments. The reason for this large deviation has been investigated in the current study, and a theoretical approach to estimate the droplet generation rate has been proposed. The suitability of the proposed model has been tested by numerically calculating the amount of metals in slag. The study shows that the weight of metals in emulsion falls in the range of 0 to 21 wt pct of hot metal weight when droplet generation rate has been calculated at ambient furnace temperature of 1873 K (1600 °C)

Towards an Airframe Noise Prediction Methodology: Survey of Current Approaches

In this paper, we present a critical survey of the current airframe noise (AFN) prediction methodologies. Four methodologies are recognized. These are the fully analytic method, CFD combined with the acoustic analogy, the semi-empirical method and fully numerical method. It is argued that for the immediate need of the aircraft industry, the semi-empirical method based on recent high quality acoustic database is the best available method. The method based on CFD and the Ffowcs William- Hawkings (FW-H) equation with penetrable data surface (FW-Hpds ) has advanced considerably and much experience has been gained in its use. However, more research is needed in the near future particularly in the area of turbulence simulation. The fully numerical method will take longer to reach maturity. Based on the current trends, it is predicted that this method will eventually develop into the method of choice. Both the turbulence simulation and propagation methods need to develop more for this method to become useful. Nonetheless, the authors propose that the method based on a combination of numerical and analytical techniques, e.g., CFD combined with FW-H equation, should also be worked on. In this effort, the current symbolic algebra software will allow more analytical approaches to be incorporated into AFN prediction methods

Use of Food to Cope With Culturally Relevant Stressful Life Events Is Associated With Body Mass Index in African American Women

BACKGROUND: Although stress is an established contributor to obesity (in general population studies), mechanisms to explain this association in African American women that incorporate culturally relevant frameworks have received little attention. OBJECTIVE: To investigate how stress is associated with body mass index (BMI) in this population, we examined multivariate models of BMI predicted by race-related, gender-related, and generic stressful life events and by use of food to cope with stress. We hypothesized that the three types of stressful life events would be indirectly associated with BMI through using food to cope with stress. METHODS: Psychometrically robust measures were included in surveys administered to a socioeconomically diverse sample of 189 African American women aged 21-78 years. Hypotheses were tested using structural equation modeling. We examined race-related, gender-related, and generic stressful life events as latent constructs indicated by exposure to and appraisal of potential stressors predicting a mediator, using food to cope, which predicted BMI; this model also included direct paths from the three latent stressful life event constructs to BMI. RESULTS: Almost every participant reported using food in some way to cope with stress; 33% and 42% met established criteria for overweight and obesity, respectively. The race-related stressful life event construct was the only latent construct predicting using food to cope with stress, and using food to cope with stress predicted BMI. A significance test of indirect effects demonstrated that the race-related stressful life event construct was indirectly associated with BMI through the mediator, using food to cope. DISCUSSION: Culturally relevant stress exposures and stress-related eating are important areas of foci for tackling overweight, obesity, and related health inequities in African American women. Findings highlight the importance of developing more complex models to understand the stress-related factors that elevate risk for overweight and obesity in this population

Using routine outcome measures as clinical process tools : maximising the therapeutic yield in the IAPT programme when working remotely

Objectives The objective of the study was to investigate the administration and use of routine outcome monitoring session by session in the context of improving guided-self-help interventions when delivered remotely at Step 2 care in the English Improving Access to Psychological Therapies (IAPT) services. Design Qualitative research using recordings of telephone-treatment sessions. Method Participants (11 patients and 11 practitioners) were recruited from four nationally funded IAPT services and one-third sector organisation commissioned to deliver Step 2 IAPT services, in England. Data collection took place prior to the COVID-19 pandemic. Transcripts of telephone–treatment sessions were analysed using thematic analysis. Results Four themes were identified: (1) lack of consistency in the administration of outcome measures (e.g. inconsistent wording); (2) outcome measures administered as a stand-alone inflexible task (e.g. mechanical administration); (3) outcome measures as impersonal numbers (e.g. summarising, categorising and comparing total scores); and (4) missed opportunities to use outcome measures therapeutically (e.g. lack of therapeutic use of item and total scores). Conclusions The administration of outcome measures needs to ensure validity and reliability. Therapeutic yield from session-by-session outcome measures could be enhanced by focusing on three main areas: (1) adopting a collaborative conversational approach, (2) maximising the use of total and items scores and (3) integrating outcome measures with in-session treatment decisions. Shifting the perception of outcome measures as impersonal numbers to being process clinical tools ensures a personalised delivery of psychological interventions and has the potential to enhance engagement from practitioners and patients what may reduce drop-out rates and improve clinical outcomes

Superhard Phases of Simple Substances and Binary Compounds of the B-C-N-O System: from Diamond to the Latest Results (a Review)

The basic known and hypothetic one- and two-element phases of the B-C-N-O system (both superhard phases having diamond and boron structures and precursors to synthesize them) are described. The attention has been given to the structure, basic mechanical properties, and methods to identify and characterize the materials. For some phases that have been recently described in the literature the synthesis conditions at high pressures and temperatures are indicated.Comment: Review on superhard B-C-N-O phase

Dynamic model of basic oxygen steelmaking process based on multi-zone reaction kinetics : model derivation and validation

A multi-zone kinetic model coupled with a dynamic slag generation model was developed for the simulation of hot metal and slag composition during the BOF operation. The three reaction zones, (i) jet impact zone (ii) slag-bulk metal zone (iii) slag-metal-gas emulsion zone were considered for the calculation of overall refining kinetics. In the rate equations, the transient rate parameters were mathematically described as a function of process variables. A micro and macroscopic rate calculation methodology (micro-kinetics and macro-kinetics) were developed to estimate the total refining contributed by the recirculating metal droplets through the slag-metal emulsion zone. The micro-kinetics involves developing the rate equation for individual droplets in the emulsion. The mathematical models for the size distribution of initial droplets, kinetics of simultaneous refining of elements, the residence time in the emulsion, dynamic interfacial area change were established in the micro-kinetic model. In the macro-kinetics calculation, a droplet generation model was employed and the total amount of refining by emulsion was calculated by summing the refining from the entire population of returning droplets. A dynamic FetO generation model based on oxygen mass balance was developed and coupled with the multi-zone kinetic model. The effect of post combustion on the evolution of slag and metal composition was investigated. The model was applied to a 200-ton top blowing converter and the simulated value of metal and slag was found to be in good agreement with the measured data. The post-combustion ratio was found to be an important factor in controlling FetO content in the slag and the kinetics of Mn and P in a BOF process

Heavy Quarks and Heavy Quarkonia as Tests of Thermalization

We present here a brief summary of new results on heavy quarks and heavy quarkonia from the PHENIX experiment as presented at the "Quark Gluon Plasma Thermalization" Workshop in Vienna, Austria in August 2005, directly following the International Quark Matter Conference in Hungary.Comment: 8 pages, 5 figures, Quark Gluon Plasma Thermalization Workshop (Vienna August 2005) Proceeding

Single Electrons from Heavy Flavor Decays in p+p Collisions at sqrt(s) = 200 GeV

The invariant differential cross section for inclusive electron production in p+p collisions at sqrt(s) = 200 GeV has been measured by the PHENIX experiment at the Relativistic Heavy Ion Collider over the transverse momentum range $0.4 <= p_T <= 5.0 GeV/c at midrapidity (eta <= 0.35). The contribution to the inclusive electron spectrum from semileptonic decays of hadrons carrying heavy flavor, i.e. charm quarks or, at high p_T, bottom quarks, is determined via three independent methods. The resulting electron spectrum from heavy flavor decays is compared to recent leading and next-to-leading order perturbative QCD calculations. The total cross section of charm quark-antiquark pair production is determined as sigma_(c c^bar) = 0.92 +/- 0.15 (stat.) +- 0.54 (sys.) mb.Comment: 329 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm