The Potential of Some Non-Conventional Vegetable Oils in Biodiesel Applications

This work studied the potentials of some non-conventional oils biodiesel as an alternative to biodiesel made from a conventional seed oil (palm kernel oil), and petroleum-based diesel. The fruits of three non-conventional oilseeds, namely:PerseaAmericana (Avocado pear), Irvingiagabonenses (Dica nut) and Darcryodesedulis (Native pear)were obtained from local markets in Ile-Ife, Osun State Nigeria while petroleum-based diesel (PBD) used for comparative study was obtained commercially.The outer fleshylayers of the fruitswere separated from the seeds while both were air-dried for some days and later milled. The oils extracted from the milled samples were esterified to produce biodiesel usingmethanol in the presence of NaOH as catalyst. The biodiesels were analyzed for their fuel properties using standard methods.Results showed that the biodiesel yield ofIrvingiagabonensisoil diesel (IGOD),Darcryodesedulisoil diesel (DEOD) and Persia americanaoil diesel (PAOD) were94%, 82% and 96% respectively. These values compared favourably with that of palm kernel oil diesel (PKOD) (91%) produced under same conditions, and with the literature standard yield of 96.5% set for biodiesel. The pour pointsof PKOD, PAOD and DEOD were3, -6 and 1oC,respectively, with PAOD pour point very close to that of PBD (≥-10oC) obtained under similar experimental conditions. Except for IGOD, all the oils have pour points within the standard range of -15 to 16oC set for biodiesel suggesting the suitability of the oils for biodiesel applications.The iodine values of the biodiesel ranged between 9.64 and 16.52 meq/kg and agreed closely with 12-18 meq/kg reported in literature for PKOD. The biodiesel blend with PBD in the ratio 10:90, 20:80, 30:70 and 40:60 demonstratedimprovedphysico-chemical properties (including smoke point, flash point, cloud point, pour point, density, viscosity and acid value) that could meet the fluidity requirements for biodiesel applications

Preferential Paths of Air-water Two-phase Flow in Porous Structures with Special Consideration of Channel Thickness Effects.

Accurate understanding and predicting the flow paths of immiscible two-phase flow in rocky porous structures are of critical importance for the evaluation of oil or gas recovery and prediction of rock slides caused by gas-liquid flow. A 2D phase field model was established for compressible air-water two-phase flow in heterogenous porous structures. The dynamic characteristics of air-water two-phase interface and preferential paths in porous structures were simulated. The factors affecting the path selection of two-phase flow in porous structures were analyzed. Transparent physical models of complex porous structures were prepared using 3D printing technology. Tracer dye was used to visually observe the flow characteristics and path selection in air-water two-phase displacement experiments. The experimental observations agree with the numerical results used to validate the accuracy of phase field model. The effects of channel thickness on the air-water two-phase flow behavior and paths in porous structures were also analyzed. The results indicate that thick channels can induce secondary air flow paths due to the increase in flow resistance; consequently, the flow distribution is different from that in narrow channels. This study provides a new reference for quantitatively analyzing multi-phase flow and predicting the preferential paths of immiscible fluids in porous structures

Peripartum Cardiomyopathy: A Case Report

ABSTRACT: Introduction & Objective: Peripartum cardiomyopathy is a rare but sometimes fatal form of heart failure during the period of 1 month antepartum to 5 months postpartum. The aim of this report is to assess the clinical presentation, management and crucial role of echocardiography in women with peripartum cardiomyopathy. Case: A 22 year-old woman, with previously healthy primipara, was admitted to the emergency ward with sever dyspnea, cough, and bloody hemoptesis and a preliminary diagnosis of pulmonary embolism (PE) two weeks after cesarean section. Neither perfusion scintigaphy nor Doppler sonography test of lower extremities and pelvis showed any evidence of PE or deep venous thrombosis. Echocardiography revealed features of left ventricular failure. A diagnosis of peripartum cardiomyopathy was made, appropriate treatment was administered and the patient improved. Conclusion: It is possible to misdiagnose peripartum cardiomyopathy with PE. Echocardiography is a valuable tool in the differential diagnosis. As a noninvasive procedure, it should be performed at the bedside as soon as possible to introduce proper treatment and to avoid potentially fatal errors

Role of critical gas saturation in the interpretation of a field scale CO2 injection experiment

Residual trapping of CO2, typically quantified by residual gas saturation (Sgr), is one of the main trapping mechanisms in geological CO2 storage (GCS). An important additional characteristic parameter is critical gas saturation (Sgc). Sgc determines at what saturation the trapped gas remobilizes again if gas saturation increases due to exsolution from the aqueous phase, rather than from further gas injection. In the present study, a pilot-scale CO2 injection experiment carried out at Heletz, Israel, in 2017, is interpreted by taking critical saturation into account. With regards to this experiment, the delayed second arrival peak of the partitioning tracer could not be captured by means of physical models. In this work, the hysteretic relative permeability functions were modified to account for Sgc. The results showed that accounting for the effect of Sgc during the secondary drainage indeed captured the observed delayed peak. The difference between the values of Sgr and Sgc, influenced both the time and peak height of the tracer arrival. To our knowledge this is first time that critical gas saturation has been considered in field scale analyses related to GCS. Accounting for Sgc is relevant where gas saturation during secondary drainage increases due to gas phase expansion or exsolution from the aqueous phase. This will happen in situations where pressure depletion occurs, e.g. due to gas leakage from fracture zones or wells or possibly because of pressure management activities. The findings also have implications for other applications such as underground gas storage as well as for geothermal reservoir management

Pore-Scale Determination of Residual Gas Remobilization and Critical Saturation in Geological CO₂ Storage:A Pore-Network Modeling Approach

Remobilization of residually trapped CO2 can occur under pressure depletion, caused by any sort of leakage, brine extraction for pressure maintenance purposes, or simply by near wellbore pressure dissipation once CO2 injection has ceased. This phenomenon affects the long-term stability of CO2 residual trapping and should therefore be considered for an accurate assessment of CO2 storage security. In this study, pore-network modeling is performed to understand the relevant physics of remobilization. Gas remobilization occurs at a higher gas saturation than the residual saturation, the so-called critical saturation; the difference is called the mobilization saturation, a parameter that is a function of the network properties and the mechanisms involved. Regardless of the network type and properties, Ostwald ripening tends to slightly increase the mobilization saturation, thereby enhancing the security of residual trapping. Moreover, significant hysteresis and reduction in gas relative permeability is observed, implying slow reconnection of the trapped gas clusters. These observations are safety enhancing features, due to which the remobilization of residual CO2 is delayed. The results, consistent with our previous analysis of the field-scale Heletz experiments, have important implications for underground gas and CO2 storage. In the context of CO2 storage, they provide important insights into the fate of residual trapping in both the short and long term

Using the MDASI-Adolescent for Early Symptom Identification and Mitigation of Symptom Impact on Daily Living in Adolescent and Young Adult Stem Cell Transplant Patients

Hematopoietic stem cell transplantation (HSCT) requires an intensive pre- and post-procedure course that leads to symptoms including fatigue, nausea/vomiting, and pain, all of which interfere significantly with activities of daily living. These symptoms place a substantial burden on patients during the time period surrounding transplant as well as during long-term recovery. The MD Anderson Symptom Inventory (MDASI) is a symptom-reporting survey that has been successfully used in adult patients with cancer and may have utility in the adolescent and young adult (AYA) population. At the Children’s Cancer Hospital at MD Anderson Cancer Center, we adopted a modified version of the MDASI, the MDASI-adolescent (MDASI-Adol), as a standard of care for clinical practice in assessing the symptom burden of patients in the peri-transplant period. We then conducted a retrospective chart review to describe the clinical utility of implementing this symptom-screening tool in AYA patients admitted to our pediatric stem cell transplant service. Here, we report our findings on the symptom burden experienced by pediatric and AYA patients undergoing stem cell transplantation as reported on the MDASI-Adol. Our study confirmed that the MDASI-Adol was able to identify a high symptom burden related to HSCT in the AYA population and that it can be used to guide symptom-specific interventions prior to transplant and during recovery. Implementing a standard symptom-screening survey proved informative to our clinical practice and could mitigate treatment complications and alleviate symptom burden