Improving particle size measurement using multi-flash imaging

An accurate calculation of the size distribution of coarse particles is crucial in the mining and quarrying industry. Machine vision has the capability to overcome many inherent limitations of traditional sieving methods and is an active research area. However, inaccurate image segmentation of particles through software based algorithms is a significant source of error. In this paper, a hardware based approach to improving image segmentation is demonstrated using multi-flash Imaging (MFI), where multiple images captured with different illumination allows depth edges around a particle to be captured through shadow information. The MFI method is compared with conventional segmentation methods such as watershed and Canny edge detection. In order to provide more accurate evaluation of performance wooden spheres of known diameter were evaluated. Imaging the size distribution of pebbles provided a practical scenario in the evaluation of MFI. The results revealed that MFI produced more accurate size estimations than conventional segmentation techniques for both the wooden spheres and pebbles, demonstrating the potential for future use in the mining industry.     

University-Based Engineering Research in the United States

This paper reports results from an NSF-supported survey of a national probability sample of U.S. engineering faculty on the nature and organization of their research activities. We analyze how engineering faculty spend their time, the types of research faculty conduct, characteristics of that research, how that research has changed over time, and the involvement of students in engineering research, based upon the engineering discipline, institutional research intensiveness and age of the respondents. These data and results represent a perspective on university-based engineering research activities from the point of view of active researchers across most of the engineering schools in the United States.     

Real-time cardiac MRI using DSPs

A real-time cardiac magnetic resonance imaging (MRI) system has been implemented using digital signal processing (DSP) technology. The system enables real-time acquisition, processing, and display of ungated cardiac movies at moderate video rates of 20 images/s. A custom graphical user interface (GUI) provides interactive control of data acquisition parameters and image display functions. Images can be compressed into moving-picture experts group (MPEG) movies, but are displayed on the console without compression during the scan. Compared to existing real-time MRI systems, implementation with DSP's allows rapid parallel computations, fast data transfers, and greater system flexibility, including the ability to scale to multiple channels, at the expense of somewhat higher component cost.     

Obesity as a risk factor for certain types of cancer

Summary and Conclusions In conclusion, obesity has been associated with increased risk for a number of different types of cancer. The evidence has been most consistent for endometrial cancer, breast cancer in postmenopausal women, and renal cell cancer. More variable results have been reported for colorectal, prostate and pancreatic cancer. Possible mechanisms by which obesity may influence cancer risk include alteration in hormonal patterns, including sex hormones and insulin, and factors such as the distribution of body fat and changes in adiposity at different ages. The increasing prevalence of obesity in many parts of the world emphasizes the importance of learning more about the relationship between obesity and cancer and the mechanisms involved in their interaction. This paper was prepared as one of the background documents for the WHO Consultation on Obesity (Geneva, Switzerland, 3–5 June 1997). For further details, please see the report of the Consultation, Obesity: preventing and managing the global epidemic (WHO/NUT/NCD/97.2).     

Local environment effects in the vibrational properties of disordered alloys: An embedded-atom method study of Ni3Al and Cu3Au

Local environment effects are important for providing a framework for understanding the changes in vibrational properties that result from disordering. In the present work the effects of local environments on thermodynamic quantities are examined using the embedded-atom method (EAM) for Ni₃Al and Cu₃Au. Projections of the density of states onto different local environments are performed, and a local cluster expansion is calculated. It is found that the contribution to the entropy from a given atom is primarily determined by the atom and its first few neighbor shells. Relaxations are seen to qualitatively change the dependence of the entropy on local environment, changing the sign of the dominant interactions. Also, relaxations are found to extend the range of point and pair interactions and to increase the importance of multisite interactions. These results suggest that a special quasi-random structure (SQS), a small supercell constructed to approximate the local environments of the disordered phase, might be able to reproduce the disordered phase vibrational thermodynamics. It is found that an eight-atom SQS can accurately represent the vibrational thermodynamic properties of the disordered phase, implying that it could be a powerful tool for firstprinciples vibrational studies.     

Ovine arylalkylamine N-acetyltransferase in the pineal and pituitary glands: differences in function and regulation

The enzyme arylalkylamine N-acetyltransferase (AANAT; EC 2.3.1.87) has been conventionally linked with the biosynthesis of melatonin within the pineal gland and retina. This study establishes that AANAT messenger RNA (mRNA) and functional enzyme occurs within the pars tuberalis (PT) and to a lesser degree within the pars distalis (PD) of the sheep pituitary gland; expression in these tissues is approximately 1/15th (PT) and 1/300th (PD) of that in the ovine pineal gland. AANAT mRNA in the PT appears to be expressed in the same cells as the Mel1a receptor. No evidence was obtained to indicate that either PT or PD cells have the ability to synthesize melatonin, suggesting that this enzyme plays a different functional role in the pituitary. We also found that cAMP regulation of the abundance of AANAT mRNA differs between the PT and pineal gland. Forskolin (10 microM) has no effect on pineal AANAT mRNA levels, yet represses expression in the PT. This suppressive influence could be mediated by ICER (inducible cAMP response early repressor), which is induced by forskolin in both tissues. Although it appears that the specific function and regulation of AANAT in the pituitary gland differ from that in the pineal gland, it seems likely that AANAT may play a role in the broader area of signal transduction through the biotransformation of amines.