Two-temperature non-chemical equilibrium analysis of Ar-CH4-O2 ICTP at reduced pressure

In present work, a two-temperature chemically non-equilibrium (2T-NCE) model has been studied for Ar-CH₄-O₂ inductively coupled thermal plasma (ICTP) at reduced pressure from the viewpoint of interaction between plasma and fuel combustion. Chemically non-equilibrium effects have been taken into account by solving mass conservation equations for each of 22 particles considering convection, diffusion and net production effects. Species density of each particle or simply particle composition was also derived from the mass conservation equation of each one taking the non chemical equilibrium effect into account. For the net production term, totally 196 chemical reactions were taken into account including dissociation, ionization and other chemical reactions and their backward reactions. Finally, heat profile due to individual reaction and the total contribution of all reactions to the heat generated has been observed.     

Kinetics of Reduction of CaO-FeO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>-MgO-PbO-SiO<Subscript>2</Subscript> Slags by CO-CO<Subscript>2</Subscript> Gas Mixtures

Kinetics of the reaction of lead slags (PbO-CaO-SiO₂-FeO _x -MgO) with CO-CO₂ gas mixtures was studied by monitoring the changes in the slag composition when a stream of CO-CO₂ gas mixture was blown on the surface of thin layers of slags (3 to 10 mm) at temperatures in the range of 1453 K to 1593 K (1180 °C to 1320 °C). These measurements were carried out under conditions where mass transfer in the gas phase was not the rate-limiting step and the reduction rates were insensitive to factors affecting mass transfer in the slag phase. The results show simultaneous reduction of PbO and Fe₂O₃ in the slag. The measured specific rate of oxygen removal from the melts varied from about 1 × 10^?6 to 4 × 10^?5 mol O cm^?2 s^?1 and was strongly dependent on the slag chemistry and its oxidation state, partial pressure of CO in the reaction gas mixture, and temperature. The deduced apparent first-order rate constant increased with increasing iron oxide content, oxidation state of the slag, and temperature. The results indicate that under the employed experimental conditions, the rate of formation of CO₂ at the gas-slag interface is likely to be the rate-limiting step.     

Decoding Reed-Solomon codes generated by any generator polynomial

A Reed-Solomon code can be generated by n=2/sup m/-1 different generator polynomials, where 2/sup m/ is the size of the field. In the letter a structure for a Reed-Solomon decoder is introduced which can decode a Reed-Solomon code generated by any generator polynomial.<>     

The ‘pessimum’ effect in an accelerated mortar bar test using 1M NaOH solution at 80°C

Highly reactive opal was incorporated in mortar bars (25 mm × 25 mm × 285 mm) in proportions of 0, 5, 10, 30 and 50% of total aggregate content, and their expansion was measured for up to 3 weeks under storage conditions of 1M NaOH at 80°C. Maximum expansion occurred when the aggregate contained 5% opal, and increasing the amount of opal caused decreasing expansions, i.e. a ‘pessimum’ effect was observed at 5% opal content. Although this effect can be explained in the standard mortar bar tests (ASTM C227 and Australian Standard AS 1141-38) on the basis of limited alkali contents in the mortar bars, it cannot be explained on this basis in the accelerated test because of large amounts of alkali available to the mortar bars. An explanation for the occurrence of the ‘pessimum’ effect in the accelerated test has been provided based on the formation of a barrier to the penetration of NaOH in the outer skin of the mortar bars containing opal contents much larger than the ‘pessimum’ proportion.     

Design of Reed-Solomon (16,12) codec for North American AdvancedTrain Control System

The design of the codec for the ATCS radio data link is considered. The code is defined. The encoding algorithm, the decoding algorithm, and Galois field arithmetic are discussed. Implementation of the Reed-Solomon codec as a stand-alone system in order to provide a possibility of real-time bit-rate measurement is discussed. The implementation of this codec using three different 8-b and 16-b microprocessors/microcomputers is described. Their complexity and throughput are discussed     

Failure of femoral nailing in the elderly

Failure of fixation of a fracture of the mid-shaft of the femur in a 73-year-old male occurred 4 weeks after insertion of a reamed Grosse-Kempf nail. The oblique locking screw had cut out, despite having been correctly sited at the primary operation. A satisfactory result was obtained following open nailing using an AO nail. Two transverse proximal locking screws provide more certain fixation in osteoporotic bone of elderly patients.     

Colposcopic evaluation of patients with abnormal cervical cytology

A total of 1580 new patients underwent colposcopic evalution in the Dysplasia Clinic at Nassau County Medical Center. Of these patients, 186 had abnormal Papanicolaou smears associated with pregnancy, 150 were referred because of in utero exposure to diethylstilbestrol, and 1244 were referred because of abnormal cervical cytologic smear or suspicious cervical or vaginal lesion. Further analysis of this latter group revealed that 1184 (95%) patients had satisfactory colposcopic evaluation, and directed biopsy showed the following: 10 cases of invasive cervical carcinoma, 9 of carcinoma in situ with microinvasion, 118 of cervical carcinoma in situ, 110 of severe dysplasia, and 424 cases of mild to moderate cervical dysplasia. All of these patients subsequently were treated accordingly. Evaluation of final histologic specimen revealed a very high correlation with colposcopically guided biopsies. In 54 patients, where colposcopic evaluation was unsatisfactory, diagnostic cold knife conization was performed. Final histologic diagnosis disclosed a more advanced lesion in 30 patients (or 56%) of this group. The result of this study shows that satisfactory colposcopic evaluation is a highly accurate method of evaluation of abnormal cervical and vaginal cytologic smear.     

System dynamics modeling for forecasting technological substitution

It is very common, nowadays, to find that a new product or technology is substituting an older one to satisfy a particular consumer need. But with the advancement of technology, there are many instances where a particular product or technology is replacing an older one while at the same time being replaced by a newer one. This relatively new substitution phenonenon can be called a multilevel substitution process. It seems that until now no effort has been directed to study the multilevel substitution cases. Moreover, any forecast made at a given point in time needs to be updated as varying circumstances influence the elements of the forecast. This paper, therefore, presents a systematic methodology for forecasting multilevel technological substitution incorporating various forms of time dependent parameters in an existing trend extrapolation model. The methodology is based on Forrester's “System Dynamics” technique. The developed model makes forecast of the market share as well as the actual size of the market of each of the competing technology or product under various assumptions about the growth of the total joint market based on past trend or future anticipations.