10,307 research outputs found

    The OnControl bone marrow biopsy technique is superior to the standard manual technique for hematologists-in-training: a prospective, randomized comparison

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    The purpose of this study was to compare a novel bone marrow device with the standard marrow needle in a prospective, randomized study in a teaching hospital employing hematologists-in-training. The new device, the OnControl Bone Marrow (OBM) Biopsy System, utilizes a battery-powered drill to insert the needle. Fifty-four bone marrows (27 standard and 27 OBM) were performed by 11 fellows under the observation and supervision of 3 attending hematologists and 1 research technologist. The primary endpoint of the study, the mean length of the marrow biopsy specimens, a surrogate for marrow quality, was determined by a pathologist in a blinded manner. The mean length of the marrow biopsy specimens was significantly longer (56%) for the OBM group (15.3 mm) than for the standard bone marrow (SBM) group (9.8 mm), P<0.003. An objectively determined secondary endpoint; mean procedure time, skin-to-skin; also favored the OBM group (175 s) versus the SBM group (292 s), P<0.007. Several subjective secondary endpoints also favored the OBM group. Only minor adverse events were encountered in the OBM and SBM study groups. It was concluded that bone marrow procedures (BMPs) performed by hematologists-in-training were significantly faster and superior in quality when performed with the OBM compared to the SBM. These data suggest that the OBM may be considered a new standard of care for adult hematology patients. OBM also appears to be a superior method for training hematology fellows

    Oil-Based Mud Cutting as an Additional Raw Material in Clinker Production

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    Oil-Based Mud (OBM) cutting is a hazardous by-product generated during oil-well drilling. Its chemical composition suggests that it might be suitable as a raw material in cement manufacturing. It is rich in calcium oxide, silica, and aluminium oxide, which are the major oxides in raw materials for cement manufacturing. In this research, OBM cutting is used as a constituent of the raw meal for cement clinker production. Raw meal mixtures were prepared by mixing different ratios of raw materials increasing OBM content. The impact of the addition of OBM cutting on the resulting clinker has been investigated. The results demonstrate that OBM cutting could be recycled in the manufacturing of Portland cement clinker. Clinker prepared using OBM cutting had very similar properties to that prepared from limestone. This result could represent an opportunity for solving an environmental problem. The addition of OBM cutting lowers the calcination temperature, and increases the rate of carbonate dissociation. However, it also leads to a higher free lime in clinker, which is a result of the presence of trace elements, such as barium. Overall, its use as a raw material in cement production could provide a cost-effective, environment-friendly route for the management of OBM cutting

    A semi-classical over-barrier model for charge exchange between highly charged ions and one-optical electron atoms

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    Absolute total cross sections for electron capture between slow, highly charged ions and alkali targets have been recently measured. It is found that these cross sections follow a scaling law with the projectile charge which is different from the one previously proposed basing on a classical over-barrier model (OBM) and verified using rare gases and molecules as targets. In this paper we develop a "semi-classical" (i.e. including some quantal features) OBM attempting to recover experimental results. The method is then applied to ion-hydrogen collisions and compared with the result of a sophisticated quantum-mechanical calculation. In the former case the accordance is very good, while in the latter one no so satisfactory results are found. A qualitative explanation for the discrepancies is attempted.Comment: RevTeX, uses epsf; 6 pages text + 3 EPS figures Journal of Physics B (scehduled March 2000). This revision corrects fig.

    Use of Oil-Based Mud Cutting Waste in Cement Clinker Manufacturing

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    Oil-based Mud (OBM) cutting waste is generated during the process of oil well drilling. The drilled rocks are removed from deep within the drilled well and pumped to the surface. The portion removed , known at "cutting", is a mixture of rocks, mud, water and oil. Most drilling companies store this waste in open yards with no specific treatment solution. The environmental regulations in Oman specify that storage should involve isolation, to prevent penetration of the contamination to the surface and underground water. This has made OBM waste an environmental problem, with an associated cost for oil companies. OBM chemical analysis shows an interesting compositionthat may be used in cement manufacture. It has high calcium, silicon and aluminium contents, which are the major oxides in cement manufacture. Also the oil contents are useful for reducing the fuel used during the calcining and clinkerization process. In this research, the OBM waste has been analysed and used as a constituent of the raw meal for cement clinker production. The impact of OBM addition on the resultant clinker has also been investigated

    Oil-based mud waste reclamation and utilisation in low-density polyethylene composites

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    Oil-based mud (OBM) waste from the oil and gas exploration industry can be valorised to tailor-made reclaimed clay-reinforced low-density polyethylene (LDPE) nanocomposites. This study aims to fill the information gap in the literature and to provide opportunities to explore the effective recovery and recycling techniques of the resources present in the OBM waste stream. Elemental analysis using inductively coupled plasma–optical emission spectrometry (ICP-OES) and X-ray fluorescence analysis, chemical structural analysis by Fourier transform infrared (FTIR) spectroscopy, and morphological analysis of LDPE/organo-modified montmorillonite (LDPE/MMT) and LDPE/OBM slurry nanocomposites by scanning electron microscopy (SEM) have been conducted. Further analysis including calorimetry, thermogravimetry, spectroscopy, microscopy, energy dispersive X-ray analysis and X-ray diffraction (XRD) was carried out to evaluate the thermo-chemical characteristics of OBM waste and OBM clay-reinforced LDPE nanocomposites, confirming the presence of different clay minerals including inorganic salts in OBM slurry powder. The microscopic analysis revealed that the distance between polymer matrix and OBM slurry filler is less than that of MMT, which suggests better interfacial adhesion of OBM slurry compared with the adhesion between MMT and LDPE matrix. This was also confirmed by XRD analysis, which showed the superior delamination structure OBM slurry compared with the structure of MMT. There is a trend noticeable for both of these fillers that the nanocomposites with higher percentage filler contents (7.5 and 10.0 wt% in this case) were indicated to act as a thermal conductive material. The heat capacity values of nanocomposites decreased about 33% in LDPE with 7.5 wt% MMT and about 17% in LDPE with 10.0 wt% OBM slurry. It was also noted, for both nanocomposites, that the residue remaining after 1000°C increases with the incremental wt% of fillers in the nanocomposites. There is a big difference in residue amount (in %) left after thermogravimetric analysis in the two nanocomposites, indicating that OBM slurry may have significant influence in decomposing LDPE matrix; this might be an interesting area to explore in the future. The results provide insight and opportunity to manufacture waste-derived renewable nanocomposites with enhanced structural and thermal properties

    Universality of K-Theory

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    We prove that graded K-theory is universal among oriented Borel-Moore homology theories with a multiplicative periodic formal group law.Comment: 12 page
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