Ink-Jet Printing System?An Analytical Computer Model

An analytical computer model of an ink jet printing system was created. Based upon the values of 13 input parameters, the program delivers predictions of the forces acting on individual drops and their resulting dynamic behavior. Predictions of drop displacements and flight times were used to infer drop pattern appearance resulting from a given input signal. The computer model was based upon theoretical work plus extensive empirical measurements. Drop behavior was predicted with modest accuracy. An improved understanding of ink jet printing systems and numerous recommendations for their use were also derived in this study.     

Learning from designing the RoboFesta—Blue Peter robots

Can children and adults learn anything from building robots? In 2001 we ran a robot design competition with the BBC TelevisionBlue Peter, program. Some 32 000 children, aged between 5 and 16 years, submitted paper designs. We built prototypes of the four winners' robots for a Robot Design MasterClass at the London Science Museum. It is widely believed that across the curriculum, robotics is a powerful force in motivating education. We ask what the children learned from the robot design process. Our answer is that they learned many things, both inside and outside the science and technology curriculum.     

Phase I IASC-ASCE Structural Health Monitoring Benchmark Problem Using Simulated Data

Structural health monitoring (SHM) is a promising field with widespread application in civil engineering. Structural health monitoring has the potential to make structures safer by observing both long-term structural changes and immediate postdisaster damage. However, the many SHM studies in the literature apply different monitoring methods to different structures, making side-by-side comparison of the methods difficult. This paper details the first phase in a benchmark SHM problem organized under the auspices of the IASC–ASCE Structural Health Monitoring Task Group. The scale-model structure adopted for use in this benchmark problem is described. Then, two analytical models based on the structure—one a 12 degree of freedom (DOF) shear-building model, the other a 120-DOF model, both finite element based—are given. The damage patterns to be identified are listed as well as the types and number of sensors, magnitude of sensor noise, and so forth. MATLAB computer codes to generate the response data for the various cases are explained. The codes, as well as details of the ongoing Task Group activities, are available on the Task Group web site at 〈http://wusceel.cive.wustl.edu/asce.shm/〉.     

Labelled-replica techniques: post-shadow labelling of intramembrane particles in freeze-fracture replicas

Three methods are described for direct post-fracture, post-shadow labelling of individual classes of intramembrane particles (IMPs) in freeze-fracture replicas of biological membranes. The P-face IMPs corresponding to the acetylcholine receptor complexes (AChRs) of vertebrate neuroeffector junctions are identified by post-replication labelling with ferritin-antibody complexes and with neurotoxin-biotin-avidin-colloidal gold affinity ligands. (The freeze-etch nomenclature of Branton et al., 1975, is used in this report.) These post-shadow labelling techniques resemble conventional en bloc labelling techniques except that the labelling reagents must penetrate a thin but discontinuous layer of platinum superimposed on the molecules of interest. In the ‘sectioned labelled-replica technique’, the replicated and labelled tissues are stained, embedded in plastic and sectioned parallel to the replica-tissue interfaces. In the direct ‘labelled-replica techniques’, the replicated and labelled samples are freeze-dried or critical point dried, the labelled surfaces are stabilized by carbon coating, and the underlying tissues are dissolved, allowing the labelled-replicas to be examined as conventional freeze-fracture replicas. The unshadowed side of each AChR IMP is shown to retain sufficient biochemical information to permit both immunospecific and neurotoxin specific labelling despite formaldehyde fixation, freezing, fracturing, platinum shadowing, and thawing in aqueous media. A new mixed ferricyanide-osmium staining method reveals electron opaque structures spanning the membrane bilayer in the same size, number and distribution as the labelled IMPs. These experiments demonstrate the feasibility of identifying individual IMPs in freeze-fracture replicas and may allow the identification of specific membrane lesions in human disease.     

When viewing variations in paintings by Mondrian, aesthetic preferences correlate with pupil size.

Observers consciously prefer Mondrian's paintings in their original orientation compared with a rotated position—the “oblique effect” (Latto, Brain, & Kelly, 2000). However, this finding's premise, that all vertical–horizontal orientations of the thick black lines in Mondrian's oeuvre are preferred, overlooks the fact that the overall balance of these images is also altered when they are reoriented. Thus, balance may regulate the oblique effect, which might influence conscious aesthetic preferences. To address this issue, we explore Hess's (1965, 1972) claim that observers will unconsciously increase their pupil diameter to pleasing images and constrict it to unpleasant images. We overcame Hess's methodological limitation of not keeping his images' luminances and contrast constant across conditions by presenting eight Mondrian paintings (1921–1944) to 30 observers on a CRT for 20 s each in either their original or seven rotated positions. Simultaneously, we measured their pupil size while asking them to report how (dis)pleasing they found each image. We found both evidence for the oblique effect (where image rotation hampers preference) and a correlation between this consciously reported aesthetic preference and unconsciously derived pupil size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implications concerning rod bundle crossflow mixing based on measurements of turbulent flow structure

An experimental study was performed to investigate the effect of flow channel geometry on fully developed turbulent flow in “clean” rod bundle flow channels. This information was sought to obtain a better understanding of crossflow mixing between rod bundle subchannels. The experiments were performed in water with a Reynolds number range from 50 000 to 200 000. The experimental flow models considered pitch-to-diameter ratios of 1.25 and 1.125. Axial components of velocity, turbulence intensity and Eulerian autocorrelation function were the primary measurements. The autocorrelation function provided an indication of the dominant frequency of turbulence and an estimate of the longitudinal macroscale by using Taylor's hypothesis. A limited amount of lateral component turbulence intensity data was also obtained.The experimental results show that rod gap spacing (pitch-to-diameter ratio) is the most significant geometric parameter affecting the flow structure. Decreasing the rod gap spacing increases the turbulence intensity, longitudinal macroscale, and the dominant frequency of turbulence. These turbulence parameters are rather insensitive to Reynolds number.The results indicate that macroscopic flow processes exist adjacent to the rod gap. This includes secondary flows and increased scale and frequency of flow pulsations when the rod gap spacing is reduced. When interpreted in terms of crossflow mixing, the results are consistent with present crossflow mixing correlations.