Acclimatization model of an aerobic bioreactor for the treatment of toxic wastewater

This work proposes a mathematical model for the acclimatization process of a bioreactor treating toxic wastewater. Experimental data was used to identify the changing kinetic parameters of the model as acclimatization progresses. It was found that only one key parameter, the specific biomass growth rate function, changed during the acclimatization process. Therefore, an acclimatization model was proposed to explain the changes of this parameter.     

Adsorption behavior of Cu2+ and UO ions on crosslinked poly[2,2-bis(acrylamido)acetic acid]

The synthesis of a water-insoluble metal ion complexing resin was carried out by radical polymerization of 2,2-bis(acrylamido) acetic acid. The resin was characterized by elemental analyses, FTIR spectroscopy, and thermal analyses. The ability to bind copper(II), iron(II), iron(III), and uranium(VI) as well as the elution of the metal ions from the loaded resins were studied. For uranyl ions, pH 5 was the optimum sorption pH value. Sorption selectivity from the binary mixture Cu(II) + U(VI) was studied at pH 2. The thermal stability is increased by adsorption of UO. According to these results a coordination mechanism is suggested for sorption of copper and uranium. © 1995 John Wiley & Sons, Inc.     

Exploring critical attributes during air traffic congestion with a fuzzy DEMATEL–ANP technique: a case study in Ninoy Aquino International Airport

Railway Engineering Science - The constant growth of air travel in the Philippines has brought about significant consequences to air traffic congestion. Given limited resources, major airports seek...     

Polarization potentials causing pacemaker oversensing

This case of ectopic pancreas found in the pre-pyloric channel of a 2-day-old infant is unique. A review of the literature reveals no other cases of symptomatic ectopic pancreas in an infant of this age. In this patient, signs and symptoms were consistent with pyloric stenosis. Upper gastrointestinal study and esophagogastroduodenoscopy (EGD) revealed the diagnosis. This case is examined and the literature is reviewed.     

Candida albicans endophthalmitis in brown heroin addicts: response to early vitrectomy preceded and followed by antifungal therapy

The management of Candida albicans endophthalmitis in intravenous drug abusers (IVDAs) has yet to be established. Early vitrectomy was previously reported as a promising treatment for C. albicans endophthalmitis. In our series, C. albicans endophthalmitis was diagnosed for 15 IVDAs. Funduscopic examinations confirmed severe vitritis in 12 patients and chorioretinitis in three. Blood and vitreal cultures were positive for C. albicans for seven and eight patients, respectively. Patients with vitritis received antifungal therapy before and after vitrectomy. Amphotericin B or fluconazole therapy was given according to the physician's preference. Vitrectomy was defined as early if it was performed within 1 week after the diagnosis of vitritis. All seven patients who underwent early vitrectomy had a favorable response without complications. Two of three patients who underwent late vitrectomy developed blindness or scotoma. Blindness was also described in two patients with vitritis who did not undergo vitrectomy. Early vitrectomy preceded and followed by antifungal therapy seems to be appropriate management of vitritis in IVDAs.     

Electrochemical Synthesis of Poly(3,4-ethylenedioxythiophene) on Steel Electrodes: Properties and Characterization

Electrodeposition of poly(3,4-ethylenedioxythiophene) by electrochemical polymerization of 3,4-ethylenedioxythiophene has been performed on steel electrodes rather than on the typically used inert electrodes (Pt, Au, graphite carbon). The polymer was generated by cyclic voltammetry, chronopotentiometry and chronoamperometry from a 10 mM monomer solution in acetonitrile with 0.1 M LiClO₄. Elemental analysis of the generated polymer indicated that the monomeric units support 0.54 positive charges balanced with CIO₄ ¹⁴⁻ counterions. Electrochemical, electrical and structural properties of the prepared material have been characterized. The good adherence of films combined with its excellent properties indicate that poly(3,4-ethylenedioxythiophene) can be a suitable material for anticorrosion applications.     

Variation in seed protein content in the annual wild Cicer species

In a search for higher seed protein content than in cultivated chickpea (Cicer arietinum L), the authors evaluated a collection of 228 accessions from the International Center for Agricultural Research in the Dry Areas (ICARDA), representing the eight annual wild species of the genus Cicer, along with 20 cultivated chickpea check lines. Variation in seed protein content ranged from 168 g kg⁻¹ in C cuneatum Hochst ex Rich to 268 g kg⁻¹ in C pinnatifidum Jaub & Spach, with an average seed protein content of 207 g kg⁻¹ over the eight wild species. C yamashitae Kitamura had the highest mean (217 g kg⁻¹), while C echinospermum PH Davis had the lowest (192 g kg⁻¹). The mean protein content of the cultivated checks was 188 g kg⁻¹. Significant variation was present in C judaicum Boiss, C pinnatifidum and C reticulatum Ladiz. C pinnatifidum had the highest number of accessions with high protein content. Overall, protein content showed negative association with harvest index, but little association with leaf area, days to maturity and canopy width. Although the variation for seed protein content of the collection showed accessions with higher protein content than with the cultivated checks, it falls within the range reported for cultivated chickpea. It is expected that agronomically superior selections from interspecific hybrids involving C arietinum and its annual relatives should not be inferior to the cultigen in protein content. Moreover, as usually occurs in distant hybridisation, unexpected epistatic effects could produce positive transgressive segregants, as has already been reported in Cicer. © 1998 Society of Chemical Industry     

Radiation grafting of N,N-dimethylaminoethylmethacrylate onto poly(ethylene terephthalate)

Summary Radiation-induced graft polymerization of N,N-dimethylaminoethylmethacrylate (DMAEMA) from 50% solution in chloroform onto poly(ethylene terephthalate) (PET) was carried out by means of mutual γ-irradiation of polymer in presence of liquid or vapor phase monomer solutions (direct method), or by grafting of monomer from this liquid solution onto polymer preirradiated in air. It has been shown higher effectiveness of grafting by the direct method from vapor phase of monomer or by the preirradiation method as compared with direct grafting from liquid monomer solution. Grafting did not affect crystallinity, transparency and durability of the starting PET. Received: 18 November 1999/Revised version: 7 February 2000/Accepted: 8 February 2000     

Characterization of residual stresses from cold expansion using spatial statistics

Residual stress fields from cold expansion have been widely used to extend the fatigue life of aircraft structures. However, the spatial statistical character of these residual stress fields has not been established and has not been incorporated in current analysis methods. The objective of this study was to establish a spatial statistical method to quantify the residual stress field around a cold expanded hole. A framework called the Spatial Analysis of Residual Stress (SpARS) was developed utilizing spatial correlation, response surface modelling techniques and statistical resampling methods to characterize the residual stress field. Our results showed that tolerance bounds on residual stress can be quantified using this method. We also demonstrated the SpARS method using recently published round robin case studies. The newly developed model will be useful for aircraft structural fatigue crack growth analyses to incorporate residual stress fields for extending inspection intervals for fatigue and fracture critical structures.