Gas pollutants removal in a single- and two-stage ejector-venturi scrubber

The absorption of SO₂ and NH₃ from the flue gas into NaOH and H₂SO₄ solutions, respectively has been studied using an industrial scale ejector–venturi scrubber. A statistical methodology is presented to characterise the performance of the scrubber by varying several factors such as gas pollutant concentration, air flowrate and absorbing solution flowrate. Some types of venturi tube constructions were assessed, including the use of a two-stage venturi tube.

The results showed a strong influence of the liquid scrubbing flowrate on pollutant removal efficiency. The initial pollutant concentration and the gas flowrate had a slight influence. The use of a two-stage venturi tube considerably improved the absorption efficiency, although it increased energy consumption.

The results of this study will be applicable to the optimal design of venturi-based absorbers for gaseous pollution control or chemical reactors.     

Skinfold thickness measurements are better predictors of body fat percentage than body mass index in male Spanish children and adolescents

OBJECTIVES: Risk factors for increased blood lead concentration (BPb) has been investigated. However, the effect of sibship and Chinese herbal medicine on BPb has not been systematically studied. In this study BPb data from voluntary testing was used to determine if Chinese herbal medicine and sibship were associated with BPb. METHODS: 319 children aged 1-7 were tested for BPb. Meanwhile, parents were interviewed to obtain information including consumption of Chinese herbal medicine, living environment, lifestyle, and sibship of the children tested. RESULTS: The mean (SD) BPb of 319 preschool children was 4.4 (2.4) micrograms/dl. The consumption of Ba-baw-san (a Chinese herbal medicine) was significantly associated with increased BPb in children (p = 0.038). Further multivariate regression analysis of BPb in 50 pairs of siblings showed the factors of being brothers explained 75% of variation for BPb, and being sisters and brother-sister explained 51% and 41% of variation respectively. CONCLUSION: Chinese herbal medicine and children's play patterns within the family expressed in different types of sibship are the main determinants of low concentrations of BPb in preschool children of Taiwan.     

Genetic algorithms optimized fuzzy logic control for the maximum power point tracking in photovoltaic system

This paper presents an intelligent control method for the maximum power point tracking (MPPT) of a photovoltaic system under variable temperature and irradiance conditions. First, for the purpose of comparison and because of its proven and good performances, the perturbation and observation (P&O) technique is briefly introduced. A fuzzy logic controller based MPPT (FLC) is then proposed which has shown better performances compared to the P&O MPPT based approach. The proposed FLC has been also improved using genetic algorithms (GA) for optimisation. Different development stages are presented and the optimized fuzzy logic MPPT controller (OFLC) is then simulated and evaluated, which has shown better performances.     

Study of cyanoethylated alfa fiber reinforced composites by dynamic mechanical analysis

Cyanoethylation of long alfa fibers was studied, and these chemically modified fibers were used to manufacture alfa-polyester composites. The dynamic mechanical thermal properties of an unsaturated polyester resin (cured) and of composites of unmodified and chemically modified alfa-polyester were studied using a dynamic mechanical analyzer over a wide temperature range. The data suggest that in spite of the fragility of the cyanoethylated alfa fibers compared to the unmodified ones, both unmodified and modified alfa-polyester composites manifest the same order of mechanical properties: T_g, tan δ and E′ values are very near in the two cases. Fragility of fibers is compensated by the better interfacial bond between the fibers and the matrix. The scanning electron micrographs of the fracture surface of the samples reveal the improved bonding at the interface between the cyanoethylated fiber and the polyester resin. The article is published in the original.     

Adjoint Monte Carlo neutron transport using cross-section probability table representation

The probability table representation of cross-sections is generally used to deal with neutron interactions in the unresolved energy range. In the frame of neutron transport methods, the capability of the probability table representation of cross-sections on the whole neutron energy range has been mentioned by Cullen (1974) and it has been already demonstrated for the Monte Carlo transport calculations by Zheng et al. (1998). Such an advantage is also illustrated here with a simple neutron propagation configuration dealt with the TRIPOLI-4 Monte Carlo transport code.     

Simultaneous detection of multiple nucleic acid targets in a homogeneous format

The acridinium ester 4-(2-succinimidyloxycarbonylethyl)phenyl-10-methylacridinium 9-carboxylate trifluoromethane sulfonate (AE), which reacts rapidly with alkaline hydrogen peroxide to produce light, has been used as a detection label in a number of assay procedures, including nucleic acid probe-based systems [Nelson et al. (1995) in Nonisotopic Probing, Blotting and Sequencing (Kricka, L. J., Ed.) pp 391-428, Academic Press, Inc., San Diego, CA]. We have synthesized a number of derivatives of this AE and characterized their chemiluminescent properties. These derivatives display significant differences in the kinetics of the chemiluminescence reaction as well as optimal pH for light production. These differences allow two or more derivatives to be simultaneously detected and quantitated in a single reaction vessel. Several of these derivatives have been covalently linked to nucleic acid probe molecules and have been further characterized in regard to chemiluminescence properties as well as hydrolysis of the ester bond in both single- and double-stranded conformations. On the basis of these properties, homogeneous assay formats utilizing DNA probes labeled with various AE derivatives were developed. Simultaneous detection and quantitation of Chlamydia trachomatis and Neisseria gonorrhoeae, the gag and pol regions of HIV, and wild-type and mutant HIV sequences was achieved with high sensitivity and discrimination.     

Trends in breast cancer screening in Missouri from 1987 to 1995, and predictions for the years 2000 and 2010

BACKGROUND: Breast cancer is a major cause of morbidity and mortality in the United States (U.S.) and Missouri. In 1992, 3,915 new breast cancer cases were diagnosed and in 1995, 1,006 deaths from breast cancer were reported in Missouri. Although breast cancer incidence has increased in Missouri in the past 20 years, there are indications that early detection has also increased during the same period. Knowledge about which segments of the population have experienced the greatest increase in mammography screening rates helps in planning and implementation of breast cancer control programs at the state level. OBJECTIVES: Examine the prevalence and trends of lifetime mammography and 2-year mammography compliance in Missouri by age, race, and education from 1987 to 1995 and make predictions for the years 2000 and 2010. METHODS: We used data from the Missouri Behavioral Risk Factor Surveillance System (BRFSS), 1987 to 1995, to estimate the prevalence of ever having had a mammogram and compliance with mammography screening guidelines within two years by race, age, and education status among Missouri women over age 18. Using linear models, we regressed breast cancer screening prevalence estimates on time to obtain trends and predictions. RESULTS: Overall, African-American women were more likely to have had a lifetime mammogram than white women. However, we found a steady increase in the prevalence of ever having had a mammogram for all groups of women defined by age and education status, except among African Americans. Increase in the prevalence of ever having had a mammogram was much higher in women age 50 and older and slightly higher among women with a high school education or less. The average prevalence of 2-year mammography screening compliance was about 60% for all groups, a rate which did not significantly change between 1987 and 1995. By the year 2000, white women will have mammography rates equal to or higher than African-American women, and the majority of all women age 50 and older (98.3% to 100%) will have had a lifetime mammogram. CONCLUSION: Missouri target populations are predicted to attain Year 2000 National Health Objectives concerning lifetime mammography. Current efforts should be continued in order to maintain levels of mammography, particularly among African-American women.     

Absorption of simple nutrients from the in vivo neurally isolated canine jejunum and ileum

BACKGROUND: The effects of intestinal transplantation on enteric absorptive function are not well understood. Our aim was to determine the effects of in situ isolation of the jejunoileum, a large animal model of jejunoileal autotransplantation, on absorption of simple nutrients from the jejunum and ileum separately. METHODS: Four groups of dogs were prepared with modified Thiry-Vella loops: group 1, neurally intact jejunum; group 2, neurally isolated jejunum; group 3, neurally intact ileum; and group 4, neurally isolated ileum. Intestinal loops were perfused with five different isosmolar solutions of NaCl alone, 30 mmol/L glucose, 2.5 mmol/L glycine, 2.5 mmol/L phenylalanine, and 5 mmol/L oleic acid at 1 to 2 weeks and 8 to 9 weeks after operation. RESULTS: Net absorption of water and electrolytes, glucose, glycine, phenylalanine, and oleic acid were not different statistically between neurally intact and neurally isolated intestinal loops at either time point. Ileal loops absorbed more than jejunal loops. CONCLUSIONS: Absorption of simple nutrients from the canine jejunum and ileum is not altered by this model of intestinal autotransplantation. These observations suggest that the extrinsic denervation that accompanies intestinal transplantation does not affect the transport systems for glucose, glycine, phenylalanine, or oleic acid.