Results of a User Study on 2D Hurricane Visualization

We present the results from a user study looking at the ability of observers to mentally integrate wind direction and magnitude over a vector field. The data set chosen for the study is an MM5 (PSU/NCAR Mesoscale Model) simulation of Hurricane Lili over the Gulf of Mexico as it approaches the southeastern United States. Nine observers participated in the study. This study investigates the effect of layering on the observer's ability to determine the magnitude and direction of a vector field. We found a tendency for observers to underestimate the magnitude of the vectors and a counter‐clockwise bias when determining the average direction of a vector field. We completed an additional study with two observers to try to uncover the source of the counter‐clockwise bias. These results have direct implications to atmospheric scientists, but may also be able to be applied to other fields that use 2D vector fields.     

New rotary valves for pulse-tube refrigerators

In most used rotary valves in GM-type pulse-tube refrigerators the rotor makes heavy mechanical contact with the stator, so the valve is liable to wear, and large torques are needed. In this paper we will describe two types of valves, which have balanced forces on the rotor. In the first valve the rotor and the stator make no mechanical contact. The second type is a contact valve, like the classical valves, but the forces on the rotor are balanced in a different way. Therefore, these valves are less liable to wear, and the torques needed to rotate the valves are small.     

Makespan estimation and order acceptance in batch process industries when processing times are uncertain

Batch process industries are characterized by complex precedence relationships between operations, which renders the estimation of an acceptable workload very difficult. A detailed schedule based model can be used for this purpose, but for large problems this may require a prohibitive large amount of computation time. We propose a regression based model to estimate the makespan of a set of jobs. We extend earlier work based on deterministic processing times by considering Erlang-distributed processing times in our model. This regression-based model is used to support customer order acceptance. Three order acceptance policies are compared by means of simulation experiments: a scheduling policy, a workload policy and a regression policy. The results indicate that the performance of the regression policy can compete with the performance of the scheduling policy in situations with high variety in the job mix and high uncertainty in the processing times. Correspondence to: C.V. Ivanescu     

Ein stochastisches,schadensmechanisches Versagensmodell für Komposite

A stochastic damage mechanics failure model of composites This paper focuses on the theoretical simulation of strength and failure of specimens with nonlocal damage. A concept is proposed for quantitative interpretation and prediction of nonlinear. nominal stress-strain curves of damaged materials like fine ceramics or intermetallic alloys. For that reason methods of damage mechanics and of probability theory are combined.     

R curves for energy dissipative materials

This paper focuses on the theoretical simulation of fracture and stable crack growth of specimens with non-local damage. The first law of thermodynamics allows the identification or definition of appropriate crack-driving forces. The results are compared with recent ideas on defining tearing resistance for uncontained yield through the energy dissipation rate. A hypothesis regarding the conversion of mechanical into thermal energies within the non-local damage region is formulated to model the fracture behaviour of energy dissipative materials with rising crack resistance characteristics. The material's capacity to develop non-local damage is assumed to decrease with the actual damage level. This decrease relates linearly with the remaining resources of the material in dissipating energy. The hypothesis, which proposes a square root function for theoretical J-R curves, is verified by the regression analysis of experimental data regarding a European round-robin test of different steels.     

R-Kurven von energiedissipativen Werkstoffen mit Schädigungszone Teil 2: Experimentelle Ermittlung von J-R Kurven

R-curves of energy dissipative materials Part 2: Experimental evaluation of J-R curves A hypothesis regarding the conversion of mechanical into thermal energies within the nonlocal damage region is formulated to model the fracture behaviour of energy dissipative materials with rising crack resistance characteristics. The material's capacity to develop nonlocal damage beyond blunting is assumed to decrease with the actual damage level. This decrease relates linearly with the remaining resources of the material in dissipating energy. The hypothesis, wich proposes a square root function for theoretical J-R curves, is verified by the regression analysis of experimental data regarding a European round robin test of different steels.     

NIST 0:45 reflectometer

The NIST 0:45 reflectometer measures the spectral reflectance factor at an influx angle of 0° and an efflux angle of 45° of colored, nonfluorescent specimens at room temperature, with widths ranging from 3 to 10 cm and heights from 3 to 20 cm and with an uncertainty of less than 0.5 in color difference units. Published in 2008 by John Wiley & Sons, Inc. Col Res Appl, 33, 94–99, 2008