Efficient Recovery of Combustibles From Coking Coal Fines

The processing of three Indian coking coal fines with feed ash values of 25.12% (S1), 22.97% (S2), and 30.38% (S3) was studied. Substantial improvement in the overall recovery of combustible could be obtained by splitting sample S1, exhibiting good washability but poor release behavior, into a coarser and a finer fraction and treating them by gravity and Jameson cell flotation, respectively. Sample S2 had over 70% of the material below 100 µm and had excellent release characteristics. The Jameson cell flotation indeed resulted in very high recovery of combustibles at the desired target ash values and split processing was not required for this sample. The floatability and washability characteristics of sample S3 indicated that gravity-based methods might improve combustible recovery in terms of theoretical yield at the desired product ash values. A combination of spiral concentration of the coarser fraction and froth flotation of the finer fraction using a Jameson cell showed some improvement in the combustible recovery of this sample. It was established in this study that if the floatability is poor or moderate, then split processing improves coal cleaning performance. Flotation alone may be recommended only when samples exhibit excellent floatability.     

Split Processing of High Ash Indian Coking Coal Fines Using Jameson Flotation Cell

The processing of two samples of high ash Indian coking coal fines (?500 μm) has been studied. Mechanical cell flotation of two coal samples resulted in poor recovery of combustibles at a specified ash content of 17%. The use of Jameson Cell for flotation was also found helpless in improving the performance. The poor recovery of combustibles was attributed to low recovery of coarse particles (>300 μm). Split processing involving spiral concentration of the coarser fraction (?500 + 100 μm) and Jameson Cell flotation of the ?100-μm fraction resulted in an improved overall performance. Substantial improvement in the yield of clean coal at the same target ash (17%) could be achieved in split processing.     

Evolution of aluminide coating microstructure on nickel-base cast superalloy CM-247 in a single-step high-activity aluminizing process

This study deals with the aluminizing of a directionally cast Ni-base superalloy, namely CM-247, by a single-step process using a high-activity pack. It is observed that significant incorporation of Al into the substrate surface during aluminizing continues over a period of about 1 hour and is not restricted merely to the first few minutes, as reported in the literature. Based on the microstructural details of the coatings formed at various stages of aluminizing, it is concluded that the coating growth in the above process takes place primarily by inward Al diffusion initially, followed by an intermediate stage when the growth involves both inward Al and outward Ni diffusion. In the final stages, the outward diffusion of Ni dominates the coating formation process. The above mechanism of coating formation is different from the one that prevails in the conventional two-step high-activity coating process in that the reaction front for the formation of NiAl remains spatially stationary despite the outward diffusion of nickel during the intermediate stage. It is also shown in the present study that the content of the Al source in the pack affects the coating structure significantly. It is further demonstrated that the microstructure of the aluminide coatings depends not only on the amount of Al incorporated in the sample during aluminizing but also on the time over which the uptake of this Al takes place.     

Reduction in the cumulative incidence rate of cervical cancer by one life time selective screening

PATIENT: A 35-year-old man had suffered from leukemia since September 1990. A transplantation of bone marrow was carried out in February 1994. He developed a graft-versus-host disease in November 1995. In December 1995 a keratoplasty was necessary because of a perforated corneal ulcer. 17 days later the patient noted a complete loss of vision, first in the left and one day later in the right eye. The optic nerve head was white and the retina looked ischaemic like in central retinal artery occlusion. A hypodensic area was found in the frontal brain reaching up to the optic chiasm in computer tomography. Inspite of intensive treatment the immunosuppressed patient died 4 days after he had become blind. Autopsy showed a mycotic infiltration by mucormycosis of the brain and the right optic nerve sheath. This human- pathogenic fungal infection belongs to the group of mould as well as aspergillus. CONCLUSION: Mycosis should be considered in the differential diagnosis of acute visual loss in immunosuppressed patients.     

Glutathione status of some homeothermic vertebrate species and its relation with diabetogenesis

The pancreatic glutathione levels of birds are higher than that of mammalian species. Refractoriness of birds towards the action of diabetogens may indeed be correlated with this fact. However, the higher pancreatic glutathione value found in owl, in comparison to that of pigeon, seems contradictory since owl is more susceptible to diabetogens.     

Preparation and in vitro dissolution profile of dual polymer (Eudragit RS100 and RL100) microparticles of diltiazem hydrochloride

A microparticulate dosage form for a highly soluble drug, diltiazem hydrochloride, was formulated with Eudragit RS100 and RL100 using a novel dual polymer technique. A mixture of diltiazem with Eudragit RS100 (low water permeability) in acetone was coacervated into soft polymer microdrops, following which a mixture of diltiazem and RL100 (high water permeability) was added to produce microparticles consisting of both polymers with diltiazem dispersed in the matrix. A second formulation was developed using the same method except using Eudragit RS100 for both steps. For a comparative study, diltiazem, Eudragit RS100 and RL100 were combined together in a single matrix and formulated into microparticles. In vitro drug release profiles using USP paddle dissolution apparatus 2 revealed that dual polymer matrix microparticles containing Eudragit RS100 in the inner and Eudragit RL100 in the outer core exhibit a suitable release profile with an initial release of the drug followed by a plateau level for the test period of 5 h. Differential scanning calorimetric analysis showed no interaction of the drug with the polymers.