Modeling the thin-slab continuous-casting mold

A three-dimensional mathematical model has been developed to compute the thermomechanical state in the mold of thin-slab continuous casters. The thin-slab mold differs from those used in conventional slab casters in that the upper portion of the broad side walls defines a funnel-shaped chamber which allows the nozzle to be submerged into the liquid metal. The chamber converges with distance down the mold, reducing to the rectangular cross section of the finished casting near the mold exit. The new mold, along with casting speeds up to 6 m/min, allows slabs to be cast 50–60 mm thick, compared with 150 to 350 mm in conventional continuous slab casting. However, the mold shape and high casting speed lead to higher mold temperatures and shorter mold life than are found in conventional slab casters. In this article, we develop mathematical models of the process to determine the role of various process parameters in determining the mold life. Finite-element analysis is used to determine the temperatures in the mold and cast slab, and these data are then used in an elastic-viscoplastic analysis to investigate the deformation of the mold wall in service. Cyclic inelastic strains up to 1.75 Pct are found in a region below the meniscus along the funnel edge. These large strains result from the combination of locally high temperatures coupled with geometric restraint of the mold. The deformation leads to short mold life because of thermal fatigue cracking of the mold. The computed locations and time to failure of the mold in fatigue agree very well with observations of the appearance of mold surface cracks in an operating caster. The models are also used to develop an improved mold design. Formerly Research Assistant, Department of Mechanical and Industrial Engineering, University of Illinois, Urbana, IL     

Soft tissue tumours

Any soft tissue swelling beneath the deep fascia should be considered a sarcoma until proven otherwise. As the most important factor in the primary treatment of these cancers is the adequacy of the primary surgical resection, it is vital to diagnose these malignant tumours pre-operatively. The modern treatment of soft tissue sarcomas may involve all modalities, but the most important aspect of treatment of a primary localised sarcoma is wide excisional surgery preserving limb function. Radiotherapy is a vital adjunct in high-grade tumours, or in tumours whose resectability is limited either by size or anatomical proximity to vital structures. Apart from a few chemosensitive sarcomas, the role of chemotherapy is limited to treatment of metastatic disease where documented response rates are no greater than 30%. As 50% of patients with high-grade sarcomas will die from metastatic disease, improvements in survival rates will only come from improvements in response to systemic therapy. No controlled trials have shown any survival benefit for adjuvant chemotherapy, although a recent meta-analysis of published data has shown a trend to increased survival at two years. Multicentre randomised trials are ongoing. The prognosis of these lesions is highly variable, but is intimately related to the anatomical site (i.e., resectability), and also the grade and size of the tumour.     

Comparison of supports for the direct synthesis of hydrogen peroxide from H2 and O2 using Au–Pd catalysts

The direct synthesis of hydrogen peroxide from H₂ and O₂ using a range of supported Au–Pd alloy catalysts is compared for different supports using conditions previously identified as being optimal for hydrogen peroxide synthesis, i.e. low temperature (2 °C) using a water–methanol solvent mixture and short reaction time. Five supports are compared and contrasted, namely Al₂O₃, -Fe₂O₃, TiO₂, SiO₂ and carbon. For all catalysts the addition of Pd to the Au only catalyst increases the rate of hydrogen peroxide synthesis as well as the concentration of hydrogen peroxide formed. Of the materials evaluated, the carbon-supported Au–Pd alloy catalysts give the highest reactivity. The results show that the support can have an important influence on the synthesis of hydrogen peroxide from the direct reaction. The effect of the methanol–water solvent is studied in detail for the 2.5 wt% Au–2.5 wt% Pd/TiO₂ catalyst and the ratio of methanol to water is found to have a major effect on the rate of hydrogen peroxide synthesis. The optimum mixture for this solvent system is 80 vol.% methanol with 20 vol.% water. However, the use of water alone is still effective albeit at a decreased rate. The effect of catalyst mass was therefore also investigated for the water and water–methanol solvents and the observed effect on the hydrogen peroxide productivity using water as a solvent is not considered to be due to mass transfer limitations. These results are of importance with respect to the industrial application of these Au–Pd catalysts.     

Musculoskeletal status and disability of MMPI profile subgroups among patients with low back pain.

Studied Minnesota Multiphasic Personality Inventory (MMPI) profiles of 362 patients with acute and chronic low back pain (LBP) for replicable homogeneous subgroups using 3 cluster-analysis procedures. Two normal and 3 clinically elevated profile subgroups were identified. The 2 normal subgroups were characterized by relatively normal musculoskeletal condition and were least disabled but differed from each other in duration of pain, presence of physical abnormalities, and daily functioning. The most pathologic profile subgroup consisted largely of acute-pain patients whose musculoskeletal condition and daily functioning were similar to those of the normal subgroups. Patients in the 3 abnormal MMPI subgroups were exposed to more LBP physical-risk factors in the workplace. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ranking with uncertain labels and its applications

The techniques for image analysis and classification generally consider the image sample labels fixed and without uncertainties. The rank regression problem studied in this paper is based on the training samples with uncertain labels, which often is the case for the manual estimated image labels. A core ranking model is designed first as the bilinear fusing of multiple candidate kernels. Then, the parameters for feature selection and kernel selection are learned simultaneously by maximum a posteriori for given samples and uncertain labels. The provable convergency Expectation Maximization (EM) method is used for inferring these parameters in an iterative manner. The effectiveness of the proposed algorithm is finally validated by the extensive experiments on age ranking task and human tracking task. The popular FG-NET and the large scale Yamaha aging database are used for the age estimation experiments, and our algorithm outperforms those state-of-the-art algorithms ever reported by other interrelated literatures significantly. The experiment result of human tracking task also validates its advantage over conventional linear regression algorithm. A short version of this paper appeared in ICME07.     

A 533-MHz BiCMOS superscalar RISC microprocessor

This 533-MHz BiCMOS very large scale integration (VLSI) implementation of the PowerPC architecture contains three pipelines and a large on-chip secondary cache to achieve a peak performance of 1600 MIPS. The 15 mm×10 mm die contains 2.7 M transistors (2M CMOS and 0.7 M bipolar) and dissipates less than 85 W. The die is fabricated in a six-level metal, 0.5-μm BiCMOS process and requires 3.6 and 2.1 V power supplies     

Active state estimation for nonlinear systems: a neural approximation approach.

In this paper, we consider the problem of actively providing an estimate of the state of a stochastic dynamic system over a (possibly long) finite time horizon. The active estimation problem (AEP) is formulated as a stochastic optimal control one, in which the minimization of a suitable uncertainty measure is carried out. Toward this end, the use of the Renyi entropy as an information measure is proposed and motivated. A neural control scheme, based on the application of the extended Ritz method (ERIM) and on the use of a Gaussian sum filter (GSF), is then presented. Simulation results show the effectiveness of the proposed approach.     

Interpersonal underpinnings of request strategies: General principles and differences due to culture and gender.

Several hypotheses derived from P. Brown and S. Levinson's (1987) politeness theory were tested with Ss from the US and Korea. Ss imagined themselves in situations in which they were to make a request. Ss then indicated exactly what they would say in each situation and what their perceptions of the request size, the hearer's power, and the closeness of their relationship with the hearer were. Consistent with Brown and Levinson's theory, power, distance, and size contributed significantly to politeness. Significant predictor variable interactions suggested that an additive model is not appropriate. Finally, there was evidence of cultural and gender differences in the weighting of these predictor variables. These differences can partially account for cultural and gender differences in language use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)