The objectives of this study are to demonstrate for the first time the use of a field portable X-Ray Fluorescence Analyzer (XRF) in a multi-media environmental survey and to use the survey results to determine if residual lead from a once-active secondary lead smelter in Cairo, Egypt, still posed a health risk to the residents when comparing results with US EPA standards. Results were analyzed to determine if relationships among the variables indicated that there were residual impacts of the former smelter. Samples collected inside and near a total of 194 dwellings were analyzed. The mean floor dust lead loading was 7.48 μg lead/ft(2). Almost 10% of the dwellings had at least one floor dust wipe sample that exceeded the United States Environmental Protection Agency's (USEPA) interior settled dust lead level of 40 μg lead/ft(2). The median paint lead level was 0.04 mg lead/cm(2). 17% of the dwellings had at least one interior paint sample that exceeded the USEPA standard of 1.0 mg lead/cm(2). Mean soil lead concentration in the study area was 458 ppm and 91 ppm outside the study area. Four of nine composite soil samples exceeded the US EPA limit for bare soil in play areas. Lead concentrations in samples collected in locations outside the study area did not exceed the limit. The highest concentration was in the plot closest to the smelter and may represent residual impact from the former smelter. Statistically significant relationships were not detected between interior floor dust lead loading and either interior paint lead loading or exterior dust lead concentration. Thus, no significant exposure from the former smelter was indicated by these analyses. This may have resulted from the time elapsed since the closing of the smelter and/or the relatively low paint lead levels. Further study is needed in other areas of Egypt near former and active lead smelters. Elevated levels of mercury and arsenic detected in soil samples do not appear to be related to the smelter but warrant further study.

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The average total lead concentration of new enamel household paints in Egypt was previously reported to be the second highest among the seven countries from Africa, Asia and South America that were included in a 2009 publication. The follow up study reported in this paper includes more than twice as many brands (11 versus 4) and samples (45 versus 20) as the initial study. Paints from three of the four brands included in the initial study were sampled again to examine possible changes. Paint from the eight brands not examined in the initial study had lower lead concentrations (4,150 ppm average) compared to brands in the initial study, 26,200 ppm resulting in an average concentration of 11,900 ppm in the follow up study. These two averages are 291-and 132-times higher, respectively, than the current U.S. limit of 90 ppm in new paints for consumer use.Paint lead concentrations in brands/colors manufactured at different times did not exhibit any overall pattern of increase or decrease. The data from the follow up and initial studies were combined using the sample collected more recently for those brand/colors collected twice, resulting in a total of fifty-two (52) samples with an average lead concentration of 14,300 ppm. The presence of lead in new paints continues to represent a threat to children and efforts are needed to cease the use of lead compounds in making paints by using readily available substitutes.In a 1997 report of the analyses of fifteen (15) new paints intended for use on the interior of houses, the median concentration, 370 ppm, and the maximum, 19,200 ppm, were much lower than those presented in this report. This is consistent with a statement in the 1997 report that anecdotal evidence that some paint companies may be starting or increasing the production of lead-based paint.

Although parallel multipliers are optimal for speed, they occupy considerable chip area. For applications with lengthy operands as cryptography, the required area grows further. On the other hand, digit multipliers reduce chip area at the expense of the number of cycles required to complete the multiplication. In such multipliers, one-or-both inputs are received serially one digit per cycle. Digit multiplier designs are°exible with respect to the digit width enabling designers to select the most suitable compromise between area and cycle count for the application under consideration. This paper proposes a new digit serial-serial multiplier that is more area e±cient compared to other functionally-similar multipliers.First, we propose a new unsigned digit serial-serial multiplier that is area e±cient. The multiplier has the ability to handle unequal-width operands. That is, one operand can be of dynamic width (unlimited digit count) and the other operand is of¯xed width. Moreover, with a small modi¯cation, the multiplier can operate on two's complement operands. Then, the design is extended to support bit-level pipelining: the critical path of the multiplier pipeline stage is independent of the operand width and the digit width. Simulation results show that the proposed multiplier reduces the area over similar multipliers by up to 28% and reduces power by up to 31%.