Dual current readout for precision plating

Bistable amplifier prevents damage in the low range circuitry of a dual scale ammeter. It senses the current and switches automatically to the high range circuitry as the current rises above a preset level

Grain refinement control in TIG arc welding

A method for controlling grain size and weld puddle agitation in a tungsten electrode inert gas welding system to produce fine, even grain size and distribution is disclosed. In the method the frequency of dc welding voltage pulses supplied to the welding electrode is varied over a preselected frequency range and the arc gas voltage is monitored. At some frequency in the preselected range the arc gas voltage will pass through a maximum. By maintaining the operating frequency of the system at this value, maximum weld puddle agitation and fine grain structure are produced

Microwave interferometer controls cutting depth of plastics

Microwave interferometer system controls the cutting of plastic materials to a prescribed depth. The interferometer is mounted on a carriage with a spindle and cutting tool. A cross slide, mounted on the carriage, allows the interferometer and cutter to move toward or away from the plastic workpiece

Grain refinement control in gas-shielded arc welding of aluminum tubing

When sections are being welded, operator varies pulse rate of power supply and simultaneously monitors signal on oscilloscope until rate is found which produces maximum arc gas voltage. Remainder of welding is performed with power supply set at this pulse rate, producing desired maximum weld puddle agitation and fine uniform weld of grain structure

System remotely inspects, measures, and records internal irregularities in piping

Video electromechanical probe visually inspects and measures internal offset and peaking of welds in relatively large piping. Irregularity dimensions are recorded on peripheral equipment consisting of video tape and X-Y plotter. The probe is used for inspection of vacuum-jacketed liquid lines that cannot be inspected externally

Adolescent Learning of Academic Vocabulary in Iceland

The fields of vocabulary instruction, literacy professional development, and global language issues framed this research. Situated in Iceland, the intervention consisted of professional development for 10th‐grade teachers focused on academic words in various subject materials, increasing the learners’ proficiency in using explicit strategies to detect word meanings, and offering learners multimodal ways of working with the vocabulary. There were no significant differences between the participants in the experimental schools (n = 157) and in the control schools (n = 88). There were gains from pretest to posttest in vocabulary and in comprehension, and there were some promising trends that distinguished the experimental group from the control group on the reading comprehension test. The nature, intensity, and length of the professional development offered to the high school teachers and the relatively short time of measurement of student outcomes are suggested explanations of the results.Fulbright Foundation/U.S. State DepartmentPre-prin

Determinants of Minority-White Differentials in Child Poverty

This paper uses data from the 1993-2001 March Current Population Survey to estimate the extent to which child living arrangements, parental work patterns, and immigration attributes shape racial and ethnic variation in child poverty. Results from multivariate analyses and a standardization technique reveal that parental work patterns as well as child living arrangements are especially consequential for black and Puerto-Rican economic circumstances. Child immigration generation and parental length of residence seem to play a detrimental role in shaping poverty among Asian, Mexican, and Central/South American children. We also found that the extent to which differences in the composition of and returns to parental resources determine white-minority economic gaps varies substantially across racial and ethnic lines. The social and economic implications of the findings for understanding racial and ethnic inequality are discussed in the final section of the article

Holocene Cyclic Records of Ice-Rafted Debris and Sea Ice Variations on the East Greenland and Northwest Iceland Margins

The dynamics of the Greenland Ice Sheet and drift of sea ice from the Arctic Ocean reaching Denmark Strait are poorly constrained. We present data on the provenance of Fe oxide detrital grains from two cores in the Denmark Strait area and compare the Fe grain source data with other environmental proxies in order to document the variations and potential periodicities in ice-rafted debris delivery during the Holocene. Based on their Fe grain geochemistry, the sediments can be traced to East Greenland sources and to more distal sites around the Arctic Basin. On the Holocene time scales of the two cores, sea ice biomarker (IP25) data, and quartz weight percent reveal positive associations with T°C and inverse associations with biogenic carbonate wt%. Trends in the data were obtained from Singular Spectrum Analysis (SSA), and residuals were tested for cyclicity. Trends on the environmental proxies explained between 15 and 90% of the variance. At both sites the primary Fe grain sources were from Greenland, but significant contributions were also noted from Banks Island and Svalbard. There is a prominent cyclicity of 800 yrs as well as other less prominent cycles for both Greenland and arctic sources. The Fe grain sources from Greenland and the circum-Arctic Ocean are in synchronization, suggesting that the forcings for these cycles are regional and not local ice sheet instabilities