Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode. We have successfully implemented both ASICs in 0.25 um CMOS technology using enclosed layout transistors and guard rings for increased radiation hardness. We present results from prototype circuits and from irradiation studies with 24 GeV protons up to 57 Mrad (1.9 x 10e15 p/cm2).Comment: 8th Tropical Seminar on Innovative Particle and Radiation Detectors, Siena, Italy (2002

Effect of Shear Surface Boundaries on Stress for Shearing Flow of Dry Metal Powders-An Experimental Study

I Introduction The mechanical behavior of granular materials is important in a wide variety of industrial, engineering, and scientific fields. Despite this many aspects of the behavior of flowing granular solids are still not well understood primarily because experimental observations of the details of such flows are quite sparse. However, experiments to test dry, cohesionless, granular materials at high shear-rates have recently been developed by The motivation for this study arose from the process of xerography. In this process a dry powder image is formed upon a xerographic plate by optical and electrostatic mechanisms. Toner, a dry, thermoplastic powder, is used and the powder image is then transferred to a sheet of ordinary Contributed by the Tribology Division of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS and presented at the ASME/ASLE Joint Tribology Conference, Pittsburgh, PA, October 20-22, 1986. Manuscript received by the Tribology Division March 8, 1986. Paper No. 86-Trib-8. paper. This process relies upon the use of both a magnetic field and the use of flow of metal powders to transport the thermoplastic powder. In this paper both the shear and normal stress results are reported for the rapid flow of aluminum beads. These results are compared with the results for the rapid flow of carbon steel beads reported earlier by Craig, Buckholz, and Domoto (1986). One of the central issues related to the prediction of granular material flow is characterization of its material properties. One view, the one adopted in this paper, is a continuum approach. Another view could consider the dynamics of the individual particles. The continuum mechanics pointof-view to describe the granular flow involves determining an appropriate constitutive equation. Experimental methods similar to those used in the characterization of fluid properties are used. Therefore, we focus on the issue of stress as a function of shear-rate. The purpose of this experiment is to study the stresses associated with the shearing motion of metal powers. The results obtained can guide the theoretical development of constitutive equations for metal powders. Stress measurements are obtained that are analogous to the type obtained in rheological tests of both viscous fluids and solid suspensions. In this experiment it is essential to control as many of the independent parameters as possible. One of these independent parameters, the fractional solids content, is the ratio of the volume occupied by the granular material to the shear-cell test volume. This parameter is maintained at a prescribed constant value for a range of experimental conditions. The average stresses on the top drive surface are then 232/Vol. 109, APRIL 1987 Transactions of the ASM

Altered emotional interference processing in the amygdala and insula in women with Post-Traumatic Stress Disorder

AbstractBackgroundPost-Traumatic Stress Disorder (PTSD) is characterized by distinct behavioral and physiological changes. Given the significant impairments related to PTSD, examination of the biological underpinnings is crucial to the development of theoretical models and improved treatments of PTSD.MethodsWe used an attentional interference task using emotional distracters to test for top-down versus bottom-up dysfunction in the interaction of cognitive-control circuitry and emotion-processing circuitry. A total of 32 women with PTSD (based on an interpersonal trauma) and 21 matched controls were tested. Event-related functional magnetic resonance imaging was carried out as participants directly attended to, or attempted to ignore, fear-related stimuli.ResultsCompared to controls, patients with PTSD showed hyperactivity in several brain regions, including the amygdala, insula, as well as dorsal lateral and ventral PFC regions.ConclusionsThese results are consistent with previous studies that have higher amygdala and insular activation in PTSD subjects. However, inhibition of suppression of PFC regions is inconsistent with the fear circuitry model hypothesized by prior research. We suggest that the specific emotional conflict task used appears to target implicit or automatic emotional regulation instead of explicit or effortful emotional regulation. This is particularly relevant as it posited that emotional regulatory difficulties in anxiety disorders such as PTSD appear to occur in implicit forms of emotion regulation

Treatment of Infected Hip Arthroplasty

The clinical outcomes of a consecutive series of deep total joint infections treated with a prosthesis retaining protocol were reviewed. The treatment of deep periprosthetic joint infections is challenging. In recent years, two-stage exchange arthroplasty has emerged as the gold standard for successful elimination of infection. With success rates averaging 82% to 96%, this treatment method has both the highest and most consistent rate of infection eradication. Another alternative in the treatment of the deep periprosthetic infection is the single-stage exchange arthroplasty. Successful eradication of infection after single-stage exchange arthroplasty has been reported to average from 60% to 83% after total hip infections. While both the single and two-stage exchange arthroplasty are viable treatment options, they are associated with negative factors such as they are time consuming, expensive, and may entail a 6- to 12-week period with a minimally functioning extremity after prosthesis removal. This paper reports the general principles of management, the treatment of acute infection occurring in the postoperative period or later, and the treatment of chronic infection by exchange arthroplasty or resection arthroplasty