416 research outputs found
EFFECTS OF WETTABILITY, LITHOLOGY, AND PERMEABILITY ON THE OPTIMUM SLUG SIZE OF LOW SALINITY WATER FLOODING IN CARBONATES: AN EXPERIMENTAL APPROACH
Low salinity water flooding has attracted academic and industry communities due to its relatively simple and applicable technology. One of the drawbacks of applying the IOR/EOR technique is the lack of the availability of low salinity water in large quantities at the reasonable cost required for a technically and environmentally successful project. To overcome this problem, the industry proposed to use produced water/sea water after dilution, and reverse osmosis filter technology to achieve the required salinity. Both techniques are quite costly and might hinder the project\u27s economic success. Low salinity water as slug size followed by high salinity water was proposed to reduce the project requirement of sweet water and make the project technically and economically more attractive. In this project, the effect of the carbonate reservoir wettability, reservoir lithology (limestone and dolomite), and permeability (low and high) on the design of low salinity slug injection has been investigated. Oil wet and water wet high permeability limestone cores and high and low permeability oil wet dolomites cores were flooded in a secondary mode by the following low salinity slug sizes 10, 20, 30, and 40% of pore volumes followed by continuous flooding with high salinity water until reaching a stable value of 100% water cut. Results indicated that in the case of a limestone environment, the wettability of the reservoir has a significant impact on the optimum LSW slug size and a lower slug size requirement was observed in the case of an oil-wet system 10% PV as compared to 30% PV for the water-wet system. In addition to that, 90% of the oil in place was recovered as compared to 60% OIP for the water wet system. The lithology of the system had no noticeable impact on the requirement for the slug size in the oil-wet environment. Low salinity flooding required relatively a smaller slug size in a high permeability environment for the dolomite oil wet system, while a low permeability system exhibited a higher oil recovery as compared to a high permeability environment. Therefore, in performing a reservoir simulation of low salinity flooding of a mixed wettability and heterogenous system, laboratory work is recommended using reservoir rock and fluid data to determine optimum slug size and relative permeability data
The Impact of Rational Decisions in Increasing the Effectiveness of Institutional Performance Case Study (Social Security Institution)
The study aims to investigate the impact of rational decision making in increasing the effectiveness of institutional performance of Social security Department in Jordan. Data were collected by means of questionnaires distributed over 180 employees in the department. Questionnaires responses were statistically analyzed using different statistical techniques. The study results y indicate a statistically significant impact of rational decision making on increasing the effectiveness of institutional performance of Social security Department as well as indicate significant impact of (participation, leadership and organizational culture) on increasing the effectiveness of institutional performance of Social security . Key words: Rational Decisions, Effectiveness, Institutional Performance
Improving the prediction of firm performance using nonfinancial disclosures: A machine learning approach
Purpose: The purpose of this study is to test whether the prediction of firm performance can be enhanced by incorporating nonfinancial disclosures, such as narrative disclosure tone and corporate governance indicators, into financial predictive models. Design/Methodology/Approach: Three predictive models are developed, each with a different set of predictors. This study utilises two machine learning techniques, random forest and stochastic gradient boosting, for prediction via the three models. The data are collected from a sample of 1250 annual reports of 125 nonfinancial firms in Pakistan for the period 2011-2020. Findings: Our results indicate that both narrative disclosure tone and corporate governance indicators significantly add to the accuracy of financial predictive models of firm performance.Practical implications: Our results offer implications for the restoration of investor confidence in the highly uncertain Pakistani market by establishing nonfinancial disclosures as reliable predictors of future firm performance. Accordingly, they encourage investors to pay more attention to these disclosures while making investment decisions. In addition, they urge regulators to promote and strengthen the reporting of such nonfinancial information. Originality: This study addresses the neglect of nonfinancial disclosures in the prediction of firm performance and the scarcity of corporate governance literature relevant to the use of machine learning techniques. <br/
The impact of supervision and educational support in improving the performance of teachers in the first three grades and the impact on improving the reading skills of their students.
The aim of this study was to reveal the impact of supervision and educational attribution in improving the performance of the teachers of the first three grades and to improve the reading skills of their students.
The study found that there were statistically significant differences between the tribal and remote applications in all sub-competencies and the total degree of teachers. The differences were in favor of the post application. The mathematical averages for the post application ranged from (3,41-3,88). The performance skills related to planning the lesson (3.88), while the "performance skills related to the evaluation" ranked last with an average of (3.41), and the general arithmetic mean of the fields (3.55). Table (1) shows that there are statistically significant differences at the level of significance (0.05 = α) between the tribal and remote applications in all sub-performance skills and the total score, and the differences were in favor of the post-application of teachers. The results of the reading skills test showed statistically significant differences between the tribal and remote applications in all secondary competencies and the total score of students. The differences were in favor of the post application. The mathematical averages for the post application ranged between (2.03-3.65) For learning to read "ranked first with the highest average score of (3.65), while" fourth level of learning to read "in the last place with an average of (2,03), and the arithmetic mean of the total score (2.97). There were also statistically significant differences at the level of significance (0.05) (α) between the tribal and remote applications Performance and skills sub-class college, came the differences in favor of the dimensional application for students
New Soliton Solutions for Systems of Nonlinear Evolution Equations by the Rational Sine-Cosine Method
In this paper, we construct new solitary solutions to nonlinear PDEs by the rational Sine and Cosine method. Moreover, the periodic solutions and bell-shaped solitons solutions to the Benjamin-Bona-Mahony and the Gardner equations are obtained. New solutions to Broer-Kaup (BK) system are also obtained. Finally, the solution of a two-component evolutionary system of a homogeneous Kdv equations of order has been investigated by the proposed method
Benign versus malignant focal liver lesions: Diagnostic value of qualitative and quantitative diffusion weighted MR imaging
AbstractBackground and objectiveDiffusion-weighted imaging has an emerging role for assessment of focal and diffuse liver diseases. The aim of this study was to evaluate the diagnostic performance of DWI for characterization of focal liver lesions (FLLs).Patients and methodsThis prospective study included 40 consecutive patients with 64 focal liver lesions, who underwent MRI of the liver. All patients had one or more hepatic focal lesion of diameter more than 1cm. DWI was reviewed (b values of 0, 50 and 600s/mm2) and the mean ADC was calculated.ResultsQuantitative assessment using ADC map was more accurate (87.5%) than qualitative assessment using DWI (75%) in characterization of FLLs. Mean ADC values of malignant lesions (0.94+0.32×10−3mm2/s) were significantly lower than those of benign lesions (2.64+0.46×10−3mm2/s), (P<0.001). Using an ADC value above 1.6×10−3mm2/s offered the best accuracy in differentiation of malignant from benign lesions (86%).ConclusionDWI is a useful tool for FLLs characterization. Because of its known pitfalls and limitations, mainly the considerable overlap of ADCs values between solid benign and malignant lesions, it should be interpreted in combination with clinical data and conventional MRI sequences
التحكم بنظام تحويل طاقة رياح متغير السرعة للحصول على الاستطاعة العظمى باستخدام الخوارزمية الجينية
يقدّم هذا البحث استراتيجة تحكم بالعنفات الريحية متغيرة السرعة والموصولة مع مولد تزامني ذي مغناطيس دائم، بهدف الحصول على أعظم استطاعة ممكنة من العنفات الريحية.
استخدمنا نموذج نظام تحويل طاقة الرياح متغير السرعةVWST(Variable speed Wind turbine conversion system) ، والمكون من عنفة ريحية، مولد تزامني ذي مغناطيس دائم PMSG (Permanent magnetic synchronous generator)، مقوم، مقطع رافع-خافض، قالبة، حمل، ومتحكم تقليدي (Proportional Integral Controller) PI لتثبيت الجهد الذي حصلنا عليه من العنفة الريحية والمولد التزامني عند سرعة رياح متغيرة، ومن ثم استخدمنا إحدى تقنيات الذكاء الصنعي والمتمثلة بالخوارزمية الجينيةGA (genetic algorithm) للحصول على مميزات أعظم استطاعة ممكنة من العنفة الريحية.
تمت نمذجة المتحكم التقليدي PI والخوارزمية الجينية باستخدام برنامج الماتلابMATLAB R2014a ومنه حصلنا على مميزات الاستطاعة الميكانيكية للعنفة الريحية وحددنا نقاط الاستطاعة الأعظمية عند كل سرعة للرياح
Modeling the Completion Time of Public School Building Projects Using Neural Networks
The Ministry of Education in Iraq is confronting a colossal deficiency in school buildings while stakeholders of government funded school buildings projects are experiencing the ill effects of extreme delays caused by many reasons. Those stakeholders are particularly worried to know ahead of time (at contract assignment) the expected completion time of any new school building project. As indicated by a previous research conducted by the authors, taking into account the opinions of Iraqi experts involved with government funded school building projects, nine major causes of delay in school building projects were affirmed through a questionnaire survey specifically are; the contractor's financial status, delay in interim payments, change orders, the contractor rank, work stoppages, the contract value, experience of the supervising engineers, the contract duration and delay penalty. In this research, two prediction models (A and B) were produced to help the concerned decision makers to foresee the expected completion time of typically designed school building projects having (12) and (18) classes separately. The ANN multi-layer feed forward with back-propagation algorithm was utilized to build up the mathematical equations. The created prediction equations demonstrated a high degree of average accuracy of (96.43%) and (96.79%) for schools having (12) and (18) classes, with (R2) for both ANN models of (79.60%) and (85.30%) respectively. It was found that the most influential parameters of both models were the ratio of the sum of work stoppages to the contract duration, the ratio of contractor's financial status to the contract value, the ratio of delay penalty to the total value of contract and the ratio of mean interim payments duration to the contract duration
Application of Laser Technology in the Non-surgical Management of Periprosthetic Joint Infection (PJI); Novel Insights from Peri-implantitis
Introduction: The management of periprosthetic joint infection (PJI) is challenging, and its socio-economic impact is significant. Moreover, the incidence of MRSA and other resistant organisms are on the rise. Recently, laser technology has been incorporated into treatment protocols of dental peri-implantitis. This review explores the possibility of using laser technology to manage peri-implantitis.
Methods: This article will provide a detailed, comprehensive, and perspective review of the existing evidence of laser technology in management of dental peri-implantitis.
Results: Dental literature investigated the efficacy of several types of lasers. It was shown that diode lasers improved periodontal probing depth (PPD) and bleeding on probing (BOP). CO2 and Nd:YAG lasers have bactericidal and decontaminant functions. Er:YAG and Er,Cr:YSGG lasers seem to have the least heat-related side effects and can be safely used for cleaning of implants in dentistry. Photodynamic therapy is shown to decontaminate 2 types of implants used in PJI.
Discussion and Conclusion: A combination of good surgical skills and application of novel technologies will deliver the best outcomes. Our aim is to provide orthopedic surgeons with the effect size and quality analysis of the current evidence behind different laser techniques to decontaminate the implant surface and preserve the surrounding tissue
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