Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling

This paper investigates the extent to which alcohol-treated carbon dioxide (CO2 ), a mixture of alcohol and CO2 equilibrated at experimental pressure and temperature, can lead to greater interfacial tension reduction and greater oil swelling than can pure CO2 . Experimental measurements of interfacial tension and swelling behavior are made using a high-pressure, high-temperature visual cell at 70 °C. Two sets of fluid pairs are used: pure CO2 and oil, and alcohol-treated CO2 and oil. Two types of oil are used: a mixture of 35% hexane and 65% decane (C6 -C10 mixture), and pure decane (pure C10 ). Ethanol and methanol are used to prepare alcohol-treated CO2 . Numerical simulations are used to estimate a reduction in the minimum miscibility pressure when using alcohol-treated CO2 . Interfacial tension between alcohol-treated CO2 and oil is found to be 0.02 to 2.2 mN/m less than that between pure CO2 and oil. Simulation results suggest that alcohol-treated CO2 yields 0.2 to 1.2 MPa lower minimum miscibility pressure compared to pure CO2 . Alcohol-treated CO2 also is found to cause 6% to 43% more swelling of oil than does pure CO2 . Interfacial tension and swelling results suggest that alcohol-treated CO2 yields better miscibility with oil compared to pure CO2 .Cited as: Saira, Yin, H., Le-Hussain, F. Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling. Advances in Geo-Energy Research, 2021, 5(4): 407-421, doi: 10.46690/ager.2021.04.0

Effect of fines migration on oil recovery from carbonate rocks

We perform single-phase and two-phase flooding on Edwards Brown rock samples. The single-phase injection was of seawater or CaCl2 brine, at successive salinities 0.63, 0.21, 0.07, 0.05, and 0 mol/L (distilled water). For CaCl2 brine experimental run, no significant fines migration or permeability decrease is observed. For seawater experimental run, distilled water injection is found to bring about the highest concentration of produced fines and most of the permeability decrease, with the ultimate permeability decrease being 99.94%. Therefore, distilled water injection is used to stimulate fines migration in the following two-phase experimental runs. Two-phase experiments are performed on four Edwards Brown rock samples using seawater or CaCl2 brine as the aqueous phase, and Soltrol® 130 or crude oil as the oleic phase. Rock samples are initially fully saturated with 0.63 mol/L of the selected aqueous solution. This is followed by injecting the selected oil at a constant rate for at least 20 pore volumes to displace brine. Next, selected brine is injected to displace oil, and finally distilled water. For CaCl2 brine, distilled water injection is found to recover no additional oil of either type of oil. However, for seawater, the fines production observed during distilled water injection is found to reduce water relative permeability by two orders of magnitude when Soltrol® 130 is used and by three orders of magnitude when crude oil is used. The seawater experimental runs also brought about additional oil recovery during distilled water injection: 18% when Soltrol® 130 is used and 3.4% when crude oil is used. This last result can be attributed to the plugging of pores due to fines migration, which can divert further injected water into previously unswept pores. Cited as: Almutairi, A., Saira, S., Wang, Y., Le-Hussain, F. Effect of fines migration on oil recovery from carbonate rocks. Advances in Geo-Energy Research, 2023, 8(1): 61-70. https://doi.org/10.46690/ager.2023.04.0

ANTECEDENTS OF CUSTOMER SERVICE ORIENTATION

Customer service orientation is about knowing customers and willingly responding their expectations. Research efforts are underway to identify antecedents of customer service orientation. This concept is essential for service sector organizations. This study has examined the impact of  Transactional leadership, Transformational leadership and perceived organizational support as antecedents of customer service orientation in the banking sector. Data from 278 respondents was gathered from bank employees in Islambad, Pakistan. Results have shown a positive and significant impact of all three antecedents on customer service orientation. This study will help banking sector organizations to design policies for enhancing customer service orientation by improving employees performance with effective leadership and supportive work environment.Â

Exploring how parents of children with unilateral hearing loss make habilitation decisions: a qualitative study

Objective This study sought to explore the decision making needs of parents managing the hearing and communication needs of children with unilateral hearing loss. Design An inductive, qualitative method was used. The data were analysed using a constant comparative approach, consistent with Grounded Theory method. Study sample Twenty one families participated in interviews yielding data on twenty two children. Each of these families had at least one child with unilateral hearing loss. The age range of the children varied from four months to sixteen years old. All parents were English speaking and received care from National Health Service Audiology departments across the United Kingdom. Results Parents valued professionals’ opinions, but information provision was inconsistent. As their children mature, parents increasingly valued their child’s input. Parent-child discussions focussed on how different management strategies fit their child’s preferences. Parents were proactive in obtaining professional advice, and integrating this with their own iterative assessment of their child’s performance. Conclusions Decision making is an iterative process. Parents make nuanced decisions which aim to preserve a sense of what is normal for them. Clinicians need to recognise the parental view, including where it may contrast with a medicalised or clinical view

Negative predictive value of ultrasound in predicting tumor-free margins in specimen sonography

OBJECTIVE: To evaluate the success of ultrasound in post-excision specimen visualization, and negative predictive value of ultrasound for estimation of tumor-free margins using histopathology as the gold standard. STUDY DESIGN: Cross-sectional analytical study. PLACE AND DURATION OF STUDY: The Aga Khan University Hospital, Karachi, Pakistan, from May 2010 till January 2013. METHODOLOGY: Sonography of all breast nodules was done before and after exicision by two female radiologists with at least five years clinical experience. All surgeries were performed by the same referring breast surgeons. All nodules were non-palpable and had histopathology as well as specimen sonography performed at AKUH. Subjects were excluded, if histopathology was not available, post-procedure sonogram not done or done in another hospital and nodules that were not seen on ultrasound. After needle localization in 47 patients using ultrasound and in 7 patients using mammogram was done, sonogram was conducted in all 54 lesions. These were then assessed by ultrasound for detection of lesion and tumor-free margins in malignant lesion. Post-excision ultrasound was performed for the evaluation of lesion whether visualized or absent with localizing needle in situ, lesion dimensions, depth measurement between the superior margin of the lesion and its edge. RESULTS: All 54 lesions were present on post-exicison scan, out of which 28 were documented as malignant and 26 as benign. Ultrasound declared all specimens as tumor-free. On histopathology, two lesions were documented as having tumor-positive margins and were proven to be invasive lobular carcinoma. Therefore, the negative predictive value of the specimen sonography for margin detection was 26/28 (92.8%). CONCLUSION: Ultrasound of the excised breast tumor specimen is a simple and reliable technique for confirmation of the tumor-free margins in non-palpable breast lesions

Re-Scaling of Energy in the Stringy Charged Black Hole Solutions using Approximate Symmetries

This paper is devoted to study the energy problem in general relativity using approximate Lie symmetry methods for differential equations. We evaluate second-order approximate symmetries of the geodesic equations for the stringy charged black hole solutions. It is concluded that energy must be re-scaled by some factor in the second-order approximation.Comment: 18 pages, accepted for publication in Canadian J. Physic