The influence of phosphorous pentoxide on the phase composition and formation of Portland clinker

The influence of phosphorous pentoxide (P₂O₅) on the phase composition and formation of Portland clinker was studied in laboratory conditions. Phosphorous pentoxide in the form of calcium phosphate was added to common cement-making raw meal in graded quantities up to 5 wt.%. The raw meal properties were studied by thermal analysis. The development of clinker formation by burning for periods ranging from 20 s to 30 min in a special semi-automatic oven with a manipulator was followed using light optical microscopy. The phase composition of clinkers burnt to equilibrium was quantified by the optical point counting method. The entry of P₂O₅ into clinker minerals was determined by electron microprobe analyses. The laboratory tests show that at 0.7 wt.% of P₂O₅ in the clinker the alite (Ca₃SiO₅) content decreases and belite (Ca₂SiO₄) content increases. At a P₂O₅ content of 4.5 wt.% alite formation was totally blocked and the resulting clinker contained free lime in equilibrium with belite.     

Condensation of a Quasi-one Dimensional Gas Within a Single Wall Carbon Nanotube

Gases adsorbed within carbon nanotubes display novel phases associated with reduced dimensionality. A quasi-one dimensional (1D) environment is realized for sufficiently small tube radii such that adsorbed atoms are constrained to move along the nanotube axis. We show that, in this quasi-1D regime, a condensation transition arises from adsorption-induced tube expansion.     

Superior neuroprotective effects of cerebrolysin in heat stroke following chronic intoxication of Cu or Ag engineered nanoparticles. A comparative study with other neuroprotective agents using biochemical and morphological approaches in the rat

The possibility that cerebrolysin, a mixture of several active fragments of neurotrophic factors and peptides induces neuroprotection following nanoparticles induced exacerbation of brain damage in heat stroke was examined in a rat model. For this purpose, the therapeutic efficacy of Cerebrolysin (2.5 or 5 ml/kg) recommended for stroke treatment was used in comparison with other drugs in standard doses recommended for such therapy in clinical situations e.g., levetiracetam (44 mg/kg), pregabalin (200 mg/kg), topiramate (40 mg/kg,i.p.) and valproate (400 mg/kg). Rats subjected to 4 h heat stress in a biological oxygen demand (BOD) incubator at 38 degrees C (Rel Humid 45-47%; Wind vel 22.4 to 25.6 cm/sec) developed profound behavioral symptoms of heat stroke e.g., hyperthermia, profuse salivation, prostration and gastric ulcerations in the stomach. These rats also exhibited marked brain pathology at this time. Thus, breakdown of the blood-brain barrier (BBB) to proteins associated with brain edema formation could be seen in these heat stressed rats as compared to control groups. The edematous brain areas showed profound neuronal damage and/or distortion in large areas of the neuropil. These pathological symptoms were further exacerbated in Cu or Ag nanoparticles treated group (50-60 nm particle size, 50 mg/kg, i.p./day for 7 days) after identical heat stress on the 8th day. Pretreatment with cerebrolysin (2.5 ml/kg, i.v.) daily for 3 days in normal rats before heat stress significantly reduced the behavioral stress symptoms and the breakdown of the BBB function, edema formation and neuronal injuries. However, the magnitude and intensity of these neuroprotective effects were much less intense in all other drug treated rats after similar heat stress. On the other hand, almost double dose of cerebrolysin (5 ml/kg) was needed to achieve comparable neuroprotection in nanoparticles treated animals after heat stress. Whereas, double dose of all other compounds was much less effective in inducing neuroprotection in nanoparticles treated heat-exposed animals. These observations are the first to show that cerebrolysin exerts the most superior neuroprotective effects in heat stress as compared to other neuroprotective agents on brain pathology in normal and in nanoparticles treated group. Furthermore, cerebrolysin in double dose was the most effective in inducing neuroprotection in nanoparticles treated heat exposed rats on brain pathology as compared to double doses of other drugs. Taken together, our results show that cerebrolysin has the most superior neuroprotective effects on brain pathology in heat stroke in both normal and nanoparticles treated rats as compared to other contemporary neuroprotective agents, not reported earlier.     

On-Line and Off-Line Routing and Scheduling of Dial-a-Ride Paratransit Vehicles

This article presents the general concepts, models, and computational techniques applied in a new dial-a-ride vehicle routing and scheduling system. The objective of this system is to improve the responsiveness, reliability, and productivity of dial-a-ride paratransit services. The developed software integrates dial-a-ride routing and scheduling principles and practical experience and explicitly considers travel time variability in urban roadway networks. Such extensive and complex integration has been made possible by improved data acquisition and processing capabilities of computer, telecommunications, and vehicle location technologies. Advanced computational methods applied in the system, such as the artificial neural network technique, which allows heuristic estimation of origin-destination travel times in a dynamic and stochastic fashion, contribute to the processing speed required to respond expeditiously and efficiently to paratransit user requests. A real scheduling problem from the city of Edmonton, Alberta, where the system was tested, is used to illustrate the positive computational experience and the capability of the developed software to handle both off-line and on-line operations.