Utilization of cellulose‐triacetate‐blended membranes for carrier‐mediated transport of some metal ions

In this study, cellulose triacetate was used as a suitable base polymer for polymer‐blended membranes for ion sensing and separation. Polymer‐blended membranes were prepared with the solvent casting technique in the presence of mixed plasticizer and a metal ion carrier known as an ionophore. 7‐Dodecenyl‐8‐hydroxy‐quinoline and N,N′‐diphenylethyl Kemp's triacid diamide, in addition to the newly synthesized 8‐[N‐acetyl‐O‐(4‐tert‐butyl benzyl)‐L‐tyrosylamino] quinoline, were used as representative examples for ionophores. The membranes were evaluated through the transport of copper and lead ions into 0.1M nitric acid as the receiving phase. The concentrations of the investigated metal ions in both phases were assayed by atomic absorption spectrometry. From this study, it can be concluded that the efficiency of the membrane, either as an ion‐transporting or as an ion‐extracting condidate, is controlled by the amount of the immobilized ionophore, the immobilization time within the membrane matrix while in contact with the receiving phase, the nature of the ionophore–metal ion complex, and so on. The carrier‐mediated transport mechanism was also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2008–2015, 2001     

Reducing cell loss in banyan based ATM switching fabrics

In this paper, we propose a new technique for reducing cell loss in multi‐banyan‐based ATM switching fabrics. We propose a switch architecture that uses incremental path reservation based on previously established connections. Path reservation is carried out sequentially within each banyan but multiple banyan planes can be concurrently reserved. We use a conflict resolution approach according to which banyans make concurrent reservation offers of conflict‐free paths to head of the line cells waiting in input buffers. A reservation offer from a given banyan is allocated to the cell whose source‐to‐destination path uses the largest number of partially allocated switching elements which are shared with previously reserved paths. Paths are incrementally clustered within each banyan. This approach leaves the largest number of free switching elements for subsequent reservations which has the effect of reducing the potential of future conflicts and improves throughput. We present a pipelined switch architecture based on the above concept of path‐clustering which we call path‐clustering banyan switching fabric (PCBSF). An efficient hardware that implements PCBSF is presented together with its theoretical basis. The performance and robustness of PCBSF are evaluated under simulated uniform traffic and ATM traffic. We also compare the cell loss rate of PCBSF to that of other pipelined banyan switches by varying the switch size, input buffer size, and traffic pattern. Copyright © 2001 John Wiley & Sons, Ltd.     

New transmission planning model

A model for optimal long-range transmission planning is proposed. The model is capable of dealing with both static and dynamic modes of transmission planning. Given the existing network and anticipating a requirement for future facilities and loads, an accurate nonlinear cost function for the system is formulated. It includes both the fixed and the variable costs for all planned lines, in addition to the cost of the power losses. The cost function is minimized subject to demand satisfaction and overloading constraints. The model includes security constraints on bus voltage magnitudes and swing angles. The AC load flow solution is included in the optimization model. The results of applying the model to a previously reported power system from the literature are discussed     

Reduction of aqueous carbonate photocatalysed by treated semiconductors

Heterogeneous photocatalysed reduction of aqueous Na₂CO₃ solution (1 m) was achieved by using phthalocyanine-coated semiconductor powders (1–3% coating) as well as bare semiconductors. The suspensions were irradiated with 254 nm light from a low-pressure mercury lamp in a nitrogen atmosphere. The phthalocyanine dyes (Fe²⁺-Pc or Co²⁺-Pc) absorb > 80% of the 254 nm radiation and thus sensitize the semiconductor. The products of reduction (CH₃OH and HCHO) were determined spectrophotometrically. The CH₃OH yields obtained are much higher than the HCHO yields, due to a photocatalysed reduction of HCHO to CH₃OH. The CH₃OH yields from coated titania increased linearly with irradiation time over the period 6–18 h. However, the straight line does not pass through the origin, and it seems that a slowing-down occurs at times > 6 h. Titania coated with both dyes gave an optimum CH₃OH yield at 2% surface coating. At higher coating percentages, phthalocyanine screens the surface, thus reducing the light reaching the semiconductor. Changing the redox potential of the phthalocyanine dye by changing its central metal from Fe to Co affects the CH₃OH yields. The bare MoS₂ photocatalyst gave a much higher CH₃OH yield due to the characteristic behaviour of the semiconducting layer-type disulphide, distinguished from that of classical semiconducting materials. In the various semiconductors studied, it seems that there is no correlation between the position of the conduction band and the yield of CH₃OH. Such correlation was argued. Generally, a decrease in the yield of CH₃OH was observed as the band gap width of the semiconductor increased. The yields of the photoproduced CH₃OH generally increased with the percentage of light absorbed at 254 nm by the various semiconductors. Irradiation leads to the production of electrons in the conduction band of the semiconductor. It is likely that the photoproduced electrons reduce CO₃²- initially to HCOO- and then to HCHO and CH₃OH.     

Combined fuzzy-logic wavelet-based fault classification technique for power system relaying

This paper presents a new approach to real-time fault classification in power transmission systems using fuzzy-logic-based multicriteria approach. Only the three line currents are utilized to detect fault types such as LG, LL, and LLG, and then to define the faulty line. An online wavelet-based preprocessor stage is used with data window of ten samples (based on 4.5-kHz sampling rate and 50-Hz power frequency). The multicriteria algorithm is developed based on fuzzy sets for the decision-making part of the scheme. Computer simulation has been conducted using EMTP programs. Results are shown and they indicate that this approach can be used as an effective tool for high-speed digital relaying, as the correct detection is achieved in less than half a cycle and that computational burden is much simpler than the recently postulated fault classification techniques.     

Oral antiplatelet efficacy of the platelet GPIIb/IIIa antagonist, DMP754 in non-human primates

Binding kinetic studies with XV459, the active form of DMP754, demonstrated comparable binding kinetics (Kd and Koff) with platelets obtained from either human or baboons which were different from that with platelets obtained from dogs. Therefore, the present study was undertaken to evaluate the antiplatelet efficacy of DMP754 following oral administration in baboons. The dose levels evaluated were 0.1 and 1.0 mg/kg, IV and 0.1, 0.3, 1.0, and 3.0 mg/kg, oral of DMP754. Oral doses of DMP754 resulted in dose- and time-related inhibition of platelet aggregation along with a modest effect on bleeding time prolongation. DMP754 at similar oral doses had 24 hours of antiplatelet effects in baboon as compared to 8-12 hours duration of antiplatelet efficacy in dogs. At maximal antiplatelet doses DMP754 demonstrated no significant effects on platelet count, clinical chemistry or hemodynamic profiles in baboons. These data suggest that DMP754 is a potent orally active antiplatelet agent with extended duration after once a day oral administration in non-human primate.     

Number of nonlinear regular s-boxes

Nonlinearity is a crucial requirement for the substitution boxes in secure block ciphers. In the Letter, the probability of linearity in any nonzero linear combination of the output co-ordinates of a randomly selected regular substitution box is calculated