Moment-method calculations on apertures using basis singularfunctions

The transmission properties of perforated perfectly conducting screens are of practical interest. The treatment of nonperiodical structures by numerical techniques, such as the method of moments, is very computer intensive. In this paper it is shown that using basis functions that incorporate the edge as well as the corner singularities, the number of unknowns can be drastically reduced. The advantages and limitations of the method are discussed. Numerical results are presented illustrating the transmission properties of arrays of square and rectangular apertures     

Disquiet in the plasma

The metaphor of plasma is taken up to present and discuss movement and engagement by participants in mixed reality installation arts. Two works involving full body video portraits exhibited through large plasma screens in a variety of public settings are covered. Machinic mediations of video realism are considered in terms of embodied interaction in which viewer-participants contribute to the ‘disquiet’ of gendered figuring. Processural, proximal and personal aspects of responsive engagement are discussed. This is extended to performativity that may lead us to critical reflection of our own actions and responses in mixed reality arts.     

Meal patterns in obese and normal weight men: the ''Gustaf'' study

OBJECTIVE: To compare the reported meal patterns between obese and normal weight men. DESIGN: A dietary survey, by means of 12 repeated telephone-administered 24-hour dietary recalls, was conducted in obese and normal weight men. The study period was three months with all seven days of the week included. The contribution of intake types to the reported daily energy intake (EI) was studied as well as the circadian distribution of EI and the reported number of intakes. SUBJECTS: 86 obese men (BMI 37.7 +/- 4.4 kg/m2, mean +/- SD) from the waiting list of the outpatient clinic completed the study altogether with 61 normal weight men (BMI 23.0 +/- 1.9 kg/m2), randomly selected from the Stockholm County Census Bureau. All men were 20-60 years old. RESULTS: Results were analyzed for Group A = all men who completed the study and for Group B = the men who exceeded the CUT-OFF 1 limit for energy intake (reasonably true report as defined by Goldberg). The obvious under-reporters amounted to 73% of the obese and to 28% of the normal weight men. The meal patterns were similar for the obese and the normal weight men. The greatest contributors to EI in both groups were cooked meals, sandwich meals, snacks and breakfast-like meals. The circadian eating pattern was mainly the same in both obese and normal weight men. The reported number of intakes was 5.3 (median) per day in all obese men vs 5.6 in all the controls (P = 0.02), and in Group B 5.3 s 5.9 (P = 0.16) intakes. No specific "obese eating style' could be detected in this study.     

Workshop on late effects of irradiation to the head and neck in infancy and childhood

A summary statement for the Workshop on Late Effects of Irradiation to the Head and Neck in Infancy and Childhood is presented. The Workshop, conducted by the National Cancer Institute with the cooperation of several other organizations, was convened to determine the present status of knowledge about thyroid disease related to irradiation of the head and neck and to develop guidelines with respect to detection, diagnosis, treatment, and followup. It was decided that surgical exploration should be considered for all palpable thyroid nodules, particularly those that are firm and clearly demarcated and appear as a "cold" area on the scan. Persons at risk because of prior irradiation to the head or neck should have regular reexaminations every one to two years.     

Nanoparticles of the Lead-free Solder Alloy Sn-3.0Ag-0.5Cu with Large Melting Temperature Depression

Due to the toxicity of lead (Pb), Pb-containing solder alloys are being phased out from the electronics industry. This has lead to the development and implementation of lead-free solders. Being an environmentally compatible material, the lead-free Sn-3.0Ag-0.5Cu (wt.%) solder alloy is considered to be one of the most promising alternatives to replace the traditionally used Sn-Pb solders. This alloy composition possesses, however, some weaknesses, mainly as a result of its higher melting temperature compared with the Sn-Pb solders. A possible way to decrease the melting temperature of a solder alloy is to decrease the alloy particle size down to the nanometer range. The melting temperature of Sn-3.0Ag-0.5Cu lead-free solder alloy, both as bulk and nanoparticles, was investigated. The nanoparticles were manufactured using the self-developed consumable-electrode direct current arc (CDCA) technique. The melting temperature of the nanoparticles, with an average size of 30 nm, was found to be 213.9°C, which is approximately 10°C lower than that of the bulk alloy. The developed CDCA technique is therefore a promising method to manufacture nanometer-sized solder alloy particles with lower melting temperature compared with the bulk alloy.     

Silicon bipolar chipset for SONET/SDH 10 Gb/s fiber-opticcommunication links

High-speed multiplexers, demultiplexers, frequency dividers, mixers, and amplifiers are key electronic components in high-speed fiber-optic communications systems such as SONET/SDH. In this paper, we present several important digital and analog integrated circuits (IC) which have been developed for use in SONET/SDH 10 Gb/s optical communication links. The circuits have been fabricated in MOSAIC 5E, an advanced silicon bipolar technology (f_T=26 GHz). The resulting chipset which amounts to a total of 10 IC's consists of multiplexers, demultiplexers, a regenerative frequency divider (2:1), a dual output limiting amplifier, and two different types of mixers for clock extraction. Specifically, the design and performance of these IC's and a hybrid clock recovery module are discussed. The high performance and potential low cost of this research chipset show that advanced silicon bipolar circuit technology can play an important role in future multigigabit fiber-optic communication systems