Experimental investigation on the impact of connate water salinity on dispersion coefficient in consolidated rocks cores during enhanced gas recovery by CO2 injection

Connate water salinity is a vital property of the reservoir and its influence on the displacement efficiency cannot be overemphasised. Despite the numerous analytical literatures on the dispersion behaviour of CO2 in CH4 at different parametric conditions, studies have so far been limited to systematic effects of the process while parameters such as connate water salinity of the reservoir has not been given much attention and this could redefine the CO2-CH4 interactions in the reservoir. This study aims to experimentally determine the effect of connate water salinity on the dispersion coefficient in consolidated porous media under reservoir conditions. A laboratory core flooding experiment depicting the detailed process of the CO2-CH4 displacement using Grey Berea sandstone core sample at a temperature of 50°C and at a pressure of 1300 psig was carried out to determine the optimum injection rate, from 0.2-0.5 ml/min, for the experimentation based on dispersion coefficients and methane recovery in the horizontal orientation. This was established to be 0.3 ml/min. At the same conditions, the effects of connate water saturation of 10% and a salinity of 0 (distilled water), 5, and 10% wt. with a CO2 injection rate of 0.3 ml/min on the dispersion coefficients was investigated. The results from the core flooding process indicated that the dispersion coefficient decreases with increasing salinity, hence the higher the density of the immobile phase (connate water) the lower the dispersion of CO2 into CH4. This is a significant finding given that the inclusion of the connate water and its salinity have an effect on the mixing of the gases in the core sample and should be given importance and included during simulation studies for field scale applications of Enhanced Gas Recovery (EGR). This is the first experimental investigation into the relationship between the connate water salinity and the dispersion coefficient in consolidated porous media. Keywords: Enhanced Gas Recovery; Dispersion Coefficient; Connate water Salinity; CO2 sequestratio

Effects of pressure decay on Non-Methane Volatile Organic Compounds (NMVOC) species distribution in domestic aerosol sprays with LPG propellants

Conventional aerosols sprays contain different Volatile Organic Compounds (VOC). These organic compounds have different properties and can have detrimental impact on air quality. This study investigated the spray performance and variation of the types of Non-Methane VOCs (NMVOCs) expelled over the life of pressurised aerosol spray can. Three types of aerosol sprays – hair sprays, deodorants, and antiperspirants were selected from the solvent-based cosmetic products. Mass Ratio (MR) of solvent (ethanol) to propellant (LPG) for all the products was analysed at pressure decay sequences of 4, 3, 2, and 1.5 bar. It was found that the MR in hair sprays expelled was significantly higher than that of antiperspirants and body sprays by 53% and 54% respectively at 4 bar. As the pressure depleted, however, the antiperspirant and body sprays’ MR decreased while that of the hair spray increased. At the lower pressures (2 bar), the hair spray had the highest MR and antiperspirant had the lowest. This finding is important in evaluating the performance of the delivery pathways of aerosol spray products and will provide insight into the effective design of atomisers with alternative “green” propellants like compressed air replacing LPG as the primary propellant in spray products

Utilization of High Volume Fraction of Binary Combinations of Supplementary Cementitious Materials in the Production of Reactive Powder Concrete

The reactive powder concrete (RPC) is one of the special concrete types that characteristics with high cement content which means high production cost and CO2 emissions to the atmosphere. Therefore, to enhance the environment as well as to develop green RPC, alternatives to cement, such as supplementary cementitious materials (SCMs) were used. Limited studies addressed the use of a high volume fraction of SCMs as a binary combination in the production of RPC. Thus, this study aims to replace a high percentage of cement (50%) with binary combinations of silica fume (SF), type F fly ash (FA) and metakaolin (MK). The experimental program included two phases. In phase one, two groups (SF+FA and MK+FA) were cast without steel fibers. Based on group performance in the first phase, one group was chosen to be used with steel fibers in the second phase. The flow rate, compressive and flexural strengths, density, ultrasonic pulse velocity and dynamic modulus of elasticity tests were conducted. The phase one results showed that SF+FA combination mixtures had better performance than MK+FA mixtures thus they were selected to be used in the second phase (with the addition of 1% volumetric fraction micro steel fibers). Results indicated that it is possible to produce sustainable RPC in which the cement can be replaced with 30% SF and 20% FA (the total replacement is 50%) in the presence of 1% steel fibers with a remarkable enhancement in compressive strength and flexural strength reached up to 44% and 10%, respectively

Performance of Green Mortar Made From Locally Available Waste Tiles and Silica Fume

The continuous depletion of natural resources used in concrete require vital replacement materials to reduce the consumptions of the natural resources. Moreover, the growth in the population increases the construction of new houses to accommodate the population, which increases the demand concrete and other construction materials. The replacement of the existing building materials with the newly materials proceed from recycling the waste materials for example, flooring tiles, which is usually disposed of in landfills without any benefit in Iraq. Therefore, this study aims to recycle locally available floor tiles waste by using it as a total alternative to fine aggregate to enhance the sustainability by reducing the depletion of natural aggregates. Three types of waste tiles were used in this research, which are marble, granite, and porcelain. Four mortar mixtures were designed, casted and tested in the research. One control mixture made from natural sand aggregate and three mixtures in which the sand was fully replaced with each of marble, granite, and porcelain waste tiles with comparable grading as that for sand. The cement was partially replaced with a 10% silica fume (SF) in all mixtures. The flowability, mechanical and durability tests of mortar mixtures were investigated. The results indicated that the combination of porcelain waste tiles aggregates with 10% silica fume imparted superior performance compared to all other mixtures with improvements of 99% in the compressive strength, 53% in the flexural strength and 17% in the water absorption resistance

Spontaneous traumatic macular hole closure in a 50-year-old woman: a case report

<p>Abstract</p> <p>Introduction</p> <p>Traumatic macular holes (TMH) are well-known complications of ocular contusion injury. Spontaneous closure occurs in approximately 50% of cases, but rarely after the age of thirty. We report a case of spontaneous closure of a full thickness macular hole due to a blunt trauma and we suggest possible mechanisms for this closure.</p> <p>Case presentation</p> <p>A 50-year-old Greek woman was referred with a history of reduced best-corrected visual acuity after blunt trauma to her right eye. Diagnosis was based on fundoscopic, optical coherence tomography as well as fluorescein angiography findings with follow-up visits at two days, 20 days and five months. Fundoscopy revealed a full-thickness TMH with a minor sub-retinal hemorrhage and posterior vitreous detachment. The presence of a coagulum in the TMH base was observed. Subsequently, TMH closure was observed.</p> <p>Conclusion</p> <p>The clot in the TMH base, potentially a hemorrhage by-product containing a significant quantity of platelets, may have simulated the clot observed after autologous serum use, thus facilitating a similar effect. This may have stimulated glial cell migration and proliferation, thus contributing to spontaneous hole closure.</p

Postcode Lotteries in Public Health - The NHS Health Checks Programme in North West London

<p>Abstract</p> <p>Background</p> <p>Postcode lotteries in health refer to differences in health care between different geographic areas. These have been previously associated with clinical services. However there has been little documentation of postcode lotteries relating to preventative health care services. This paper describes a postcode lottery effect in relation to the NHS Health Checks Programme (a national cardiovascular screening programme in England) in eight PCTs in the North West sector of London.</p> <p>Methods</p> <p>A descriptive cross-sectional analysis of the Health Checks Programme was carried out in eight PCTs in North West London using a structured data-collecting instrument.</p> <p>Results</p> <p>The analysis found variation in the implementation of the national Health Checks Programme in terms of: the screening approach taken; the allocated budget (which varied from £69,000 to £1.4 million per 100,000 eligible population); payment rates made to providers of Health Checks; tools used to identify and measure risk of cardiovascular disease and diabetes; monitoring and evaluation; and preventative services available following the health check.</p> <p>Conclusions</p> <p>This study identifies a postcode lottery effect related to a national public health programme. Although it is important to allow enough flexibility in the design of the Health Checks Programme so that it fits in with local factors, aspects of the programme may benefit from greater standardisation or stronger national guidance.</p

Evaluation of a New Balloon Catheter for Difficult Calcified Lesions in Infrainguinal Arterial Disease: Outcome of a Multicenter Registry

The purpose of this study was to assess the technical performance and immediate procedure outcome of a new balloon catheter in the treatment of calcified lesions in infrainguinal arterial disease. Seventy-five patients with infrainguinal arterial disease were prospectively entered into the registry. The catheter (ReeKross Clearstream, Ireland) is a 5- to 6-Fr balloon catheter with a rigid shaft intended for enhanced pushability. Only technical procedural outcome was recorded. Treated calcified lesions (range: 5–30 cm), assessed angiographically, were located in the superficial femoral, popliteal, and crural arteries. In 67 patients the lesion was an occlusion. Guidewire passage occurred subintimally in 68 patients. In 24 patients a standard balloon catheter was chosen as first treatment catheter: 5 failed to cross the lesion, 8 balloons ruptured, and in 11 patients there was an inadequate dilatation result. In only one of the five patients did subsequent use of the ReeKross catheter also fail in lesion crossing. The ReeKross was successful as secondary catheter in the other 23 cases. In 50 patients the ReeKross was used as primary catheter. In total the ReeKross crossed the lesions in 74 patients. After passage and dilatation with this catheter in 73 patients (1 failed true-lumen reentry), 19 had >30% residual lesions, of which 11 were not treated and 8 were successfully stented. No ReeKross balloons ruptured. We conclude that in the treatment of difficult calcified lesions in arterial stenotic or occlusive disease, the choice of a high-pushability angioplasty catheter, with more calcification-resistant balloon characteristics, like the ReeKross, warrants consideration

Is the Rehbein procedure obsolete in the treatment of Hirschsprung’s disease?

Contains fulltext : 87916.pdf (publisher's version ) (Closed access)PURPOSE: After 25 years of practice and positive results of the Rehbein-procedure (RB) for children with Hirschsprung Disease (HD), we changed to the less invasive transanal endorectal pull through (TERPT). The aim of this study was to compare short- and mid-term complications of these two procedures in our patients with HD. METHODS: Retrospective data of 50 HD patients were analyzed. Of these patients, 25 underwent RB (2000-2006) and in 25 the TERPT was performed (2005-2009). Medical records were reviewed to score complications and outcomes. Differences were analyzed using Chi-Square and Mann-Whitney U tests. RESULTS: All RB patients (100%) were given a colostomy compared with four patients (16%) in the TERPT group (p < 0.001). The average age at surgery in the RB group was 191 days whereas this was 72 days in the TERPT group (p < 0.01). The mean length of time of surgery in the RB group (158 min) was not significantly different from that in the TERPT group (183 min). Ganglion cells were located in all specimens at the proximal end of the specimens. The median time to first feeding significantly decreased from 2 days (range 1-11) in the RB group to 1 day (range 1-3) in the TERPT group (p < 0.01). The median length of hospital stay decreased in the TERPT group (8 days) compared with the RB group (10 days) (p < 0.001). There was a significant reduction in postoperative obstructive symptoms during the first 6 months in the TERPT group (48%) compared with the RB group (84%) (p = 0.016). Postoperative enterocolitis decreased from 40% in the RB group to 24% in the TERPT group although this was not statistically significant. CONCLUSIONS: The introduction of TERPT reduced the need for colostomies; it shortened days to first feeding after surgery and reduced hospital stay. It also improved short-term outcome with less obstructive symptoms. We recommend TERPT surgery as a first choice in children with HD. we consider the RB now to be obsolete.1 november 201