Hot-rolling simulation and modelling using Gleeble 1500

Using the Gleeble 1500, incremental and continuous hot compression tests, simulating hot rolling, were performed on C-Mn, Nb-T, and Nb steels with test temperatures varying between 875 and 1100°C and strain rates between 0.5 and 20 s^?1. Four models are proposed. The stress peak model allows the prediction of continuous stress-strain curves from incremental curves and vice versa through the use of stress restoration index K. Variation in K for Nb-T₁, C-Mn and Nb steels at strain rates of 3, 12 and 20 s^?1 was found to be negligible. The predicted stress strain curve corresponds to experimental stress strain curve at same temperature and strain rate. The strain history model predicts continuous strain-time curves from incremental stress-strain curves using ‘constant’ ‘negative strain’ restoration index. At 950°C, with holding time 2 s and strain rate 12 s^?1, strain time decay curves obtained for C-Mn, Nb and Nb-T, steels were ε = 1.5e^?05t, ε = 1.2e^?0.36t and ε = e^?0.3t, respectively. The creep model analysis relates creep strain rate to the testing strain rate. For Nb steel at 875°C, and test strain rate of 12 s^?1, ?_creep was found to be 9.5 s^?1. The stress history model predicts continuous stress-time curves from incremental stress-time curves. Stress decay curve for C-Mn steel at 1100°C and ? = 3s^?1 was found to be σ = 181e^?0.04t. Hot rolling characteristics of steels can be accurately predicted using hot compression tests and proposed models.     

Embedded micromachined fiber-optic Fabry-Perot pressure sensors in aerodynamics applications

Small size, high bandwidth pressure sensors are required for instrumentation of probes and test models in aerodynamic studies of complex unsteady flows. Optical-fiber pressure sensors promise potential advantages of small size and low cost in comparison with their electrical counterparts. We describe miniature Fabry-Perot cavity pressure sensors constructed by micromachining techniques in a turbine test application. The sensor bodies are 500 /spl mu/m squared, 300 /spl mu/m deep with a /spl sim/2 /spl mu/m-thick copper diaphragm electroplated on one face. The sensor cavity is formed between the diaphragm and the cleaved end of a single mode fiber sealed to the sensor by epoxy. Each sensor is addressed interferometrically in reflection by three wavelengths simultaneously, giving an unambiguous phase determination; a pressure sensitivity of 1.6 radbar/sup -1/ was measured, with a typical range of vacuum to 600 kPa. Five sensors were embedded in the trailing edge of a nozzle guide vane installed upstream of a rotor in a full-scale turbine stage transient test facility. Pressure signals in the trailing edge flow show marked structure at the 8 kHz blade passing frequency. To our knowledge, this is the first report of sensors located at the trailing edge of a normal-sized turbine blade.     

Parallel FFT-based Poisson solver for isolated three-dimensional systems

We describe an implementation to solve Poisson?s equation for an isolated system on a unigrid mesh using FFTs. The method solves the equation globally on mesh blocks distributed across multiple processes on a distributed-memory parallel computer. Test results to demonstrate the convergence and scaling properties of the implementation are presented. The solver is offered to interested users as the library PSPFFT.

Program summary

Program title: PSPFFTCatalogue identifier: AEJK_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJK_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 110 243No. of bytes in distributed program, including test data, etc.: 16 332 181Distribution format: tar.gzProgramming language: Fortran 95Computer: Any architecture with a Fortran 95 compiler, distributed memory clustersOperating system: Linux, UnixHas the code been vectorized or parallelized?: Yes, using MPI. An arbitrary number of processors may be used (subject to some constraints). The program has been tested on from 1 up to ∼ 13 000 processors. RAM: Depends on the problem size, approximately 170 MBytes for 48³ cells per process.Classification: 4.3, 6.5External routines: MPI (http://www.mcs.anl.gov/mpi/), FFTW (http://www.fftw.org), Silo (https://wci.llnl.gov/codes/silo/) (only necessary for running test problem).Nature of problem: Solving Poisson?s equation globally on unigrid mesh distributed across multiple processes on distributed memory system.Solution method: Numerical solution using multidimensional discrete Fourier Transform in a parallel Fortran 95 code.Unusual features: This code can be compiled as a library to be readily linked and used as a blackbox Poisson solver with other codes.Running time: Depends on the size of the problem, but typically less than 1 second per solve.     

Evolution of 3D mobile games development

3D computer graphics have been an important feature in games development since it was first introduced in the early 80s and there is no doubt that 3D based content is often viewed as more attractive in games than the more abstract 2D graphics. Many games publishers are keen to leverage their success in the console market into the mobile phone platform. However, the resource constraints of mobile phones and the fragmented nature of the environment present considerable challenges for games developers. In this paper we consider some of the current constraints together with current and, probable, future developments both in the software and hardware of mobile phones. As part of this process we benchmark some of the latest and most prevalent software and hardware devices to ascertain both the quality of the graphics produced and the effects upon battery life. Whilst our test results highlight that the current market does indeed present challenges, our research into the future developments highlights the fact we are approaching greater standardization, which will be an important factor for the successful development of 3D mobile games.

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Condom Use Among High-Risk Adolescents: Testing the Influence of Alcohol Use on the Relationship of Cognitive Correlates of Behavior.

The goal of this study was the exploration of distal effects of alcohol use on condom use. Criminally involved adolescents completed an initial measure of attitudes, beliefs, and prior behavior. Of the 300 who completed the initial measurement, 267 (89%) completed a behavioral assessment 6 months later. Analyses validated a theoretical model of condom use intentions and indicated that intentions and attitudes measured at baseline were significant predictors of condom use behavior 6 months later. Neither alcohol use nor alcohol problems moderated relationships among model variables or the influence of intentions and attitudes on behavior. The findings do not support a distal role for alcohol use in altering the cognitive correlates of condom use intentions and behavior among high-risk adolescents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sidney Orgel (1926-2003).

Presents an obituary for Sidney Orgel (1926-2003). Bud, as everyone knew him, received his bachelor's degree from New York University in 1948. He completed his master's (1950) and doctoral (1956) degrees in clinical psychology at the University of Connecticut. Bud joined the staff of the Syracuse Veterans Administration Hospital in 1956 and then in 1968 moved to the State University of New York Upstate Medical Center to develop a Division of Clinical Psychology. He remained at Upstate for the rest of his career and in 1993 was appointed professor emeritus. The high esteem in which he was held at Upstate is reflected in his selection as acting chair of the Department of Psychiatry, a position he held from 1981 to 1985 and a rare position for a psychologist. It was at Upstate that Bud's unique talents flourished. His first accomplishment was the development of one of the country's outstanding clinical psychology internships. The training and education of psychologists became a passion for him. Interns adored him, not only because he was an outstanding supervisor, but also because his trainees knew that his goal was providing them with the best possible experience and training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fracture Toughness of Advanced Structural Ceramics: Applying ASTM C1421

The three methods of determining the quasi‐static Mode I fracture toughness (K_Ic) (surface crack in flexure—SC, single‐edge precracked beam—PB, and chevron‐notched beam—VB) found in ASTM C1421 were applied to a variety of advanced ceramic materials. All three methods produced valid and comparable K_Ic values for the Al₂O₃, SiC, Si₃N₄, and SiAlON ceramics examined. However, not all methods could successfully be applied to B₄C, ZrO₂, and WC ceramics due to a variety of material factors. The coarse‐grained microstructure of one B₄C hindered the ability to observe and measure the precracks generated in the SC and PB methods while the transformation toughening in the ZrO₂ prevented the formation of the SC and PB precracks and thus made it impossible to use either method on this ceramic. The high strength and elastic modulus of the WC made it impossible to achieve stable crack growth using the VB method because the specimen stored a tremendous amount of energy prior to fracture. Even though these methods have passed the rigors of the standardization process there are still some issues to be resolved when the methods are applied to certain classes of ceramics. It is recommended that, when appropriate, at least two of these methods be employed to determine the K_Ic, especially when a new or unfamiliar ceramic is being evaluated.     

Pre-adolescent children exhibit lower aerosol particle volume emissions than adults for breathing,speaking, singing and shouting

Speaking and singing are activities linked to increased aerosol particle emissions from the respiratory system, dependent on the utilized vocal intensity. As a result, these activities have experienced considerable restrictions in enclosed spaces since the onset of the COVID-19 pandemic due to the risk of infection from the SARS-CoV-2 virus, transmitted by virus-carrying aerosols. These constraints have affected public education and extracurricular activities for children as well, from in-person music instruction to children’s choirs. However, existing risk assessments for children have been based on emission measurements of adults. To address this, we measured the particle emission rates of 15 pre-adolescent children, all eight to ten years old, with a laser particle counter for the test conditions: breathing at rest, speaking, singing and shouting. Compared with values taken from 15 adults, emission rates for breathing, speaking and singing were significantly lower for children. Particle emission rates were reduced by a factor of 4.3 across all conditions, whereas emitted particle volume rates were reduced by a factor of 4.8. These data can supplement SARS-CoV-2 risk management scenarios for various school and extracurricular settings.     

Probability distributions of gas hydrate formation

Induction time distributions for gas hydrate formation were measured for gas mixtures of methane + propane at pressures up to 11.3 MPa using a high‐pressure automated lag time apparatus (HP‐ALTA). Measurements were made at subcooling temperatures between 4.3 and 13.5 K and, while isothermal induction times between 0 and 15,000 s were observed, the median isothermal induction times for the distributions ranged from 100 to 4000 s. A hyperbolic relationship between median induction time and subcooling was used to correlate the data. A graphical interpretation is presented that relates the two types of data that can be acquired by using the HP‐ALTA in one of two modes to study hydrate formation: induction time distributions at constant subcooling and formation temperature distributions observed during linear cooling ramps. The equivalence of these two modes provides a robust method for studying the variation of formation phenomena in different hydrate systems. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2640–2646, 2013