Development of an Optical System for Measuring Fluorescence Lifetimes

This project presents the design of a cost-effective, portable, and simplified fluorescence detection system for measuring fluorescence lifetime decay as an alternative to the available methods currently in use. There are multiple systems available to detect fluorescence of a sample, but they contain multiple parts and require expensive equipment in order to function. Due to the number of parts needed, the cost of implementing those fluorescence lifetime decay measuring systems are high. The fluorescence measuring system will be simplified into four main components that are interchangeable based on the application needs.In this project, a simple fluorescence measuring system will be used to detect a sample of quantum dots and a sample of an organic based dye and examine the results for system feasibility. Future works may include testing of various time decaying quantum dots, and testing of various other light detection devices, such as other avalanche photodiodes (APD) or photomultiplier tubes (PMTs)

A novel machine learning model for autonomous analysis and diagnosis of well integrity failures in artificial-lift production systems

The integrity failure in gas lift wells had been proven to be more severe than other artificial lift wells across the industry. Accurate risk assessment is an essential requirement for predicting well integrity failures. In this study, a machine learning model was established for automated and precise prediction of integrity failures in gas lift wells. The collected data contained 9,000 data arrays with 23 features. Data arrays were structured and fed into 11 different machine learning algorithms to build an automated systematic tool for calculating the imposed risk of any well. The study models included both single and ensemble supervised learning algorithms (e.g., random forest, support vector machine, decision tree, and scalable boosting techniques). Comparative analysis of the deployed models was performed to determine the best predictive model. Further, novel evaluation metrics for the confusion matrix of each model were introduced. The results showed that extreme gradient boosting and categorical boosting outperformed all the applied algorithms. They can predict well integrity failures with an accuracy of 100% using traditional or proposed metrics. Physical equations were also developed on the basis of feature importance extracted from the random forest algorithm. The developed model will help optimize company resources and dedicate personnel efforts to high-risk wells. As a result, progressive improvements in health, safety, and environment and business performance can be achieved.Cited as: Salem, A. M., Yakoot, M. S., Mahmoud, O. A novel machine learning model for autonomous analysis and diagnosis of well integrity failures in artificial-lift production systems. Advances in Geo-Energy Research, 2022, 6(2): 123-142. https://doi.org/10.46690/ager.2022.02.0

Enhancement of On-grid PV System under Irradiance and Temperature Variations Using New Optimized Adaptive Controller

Solar Energy is one of the key solutions to future electrical power generation. Photovoltaic Plants (PV) are fast growing to satisfy electrical power demand. Different maximum power point tracking techniques (MPPT) are used to maximize PV systems generated power. In this paper, on grid PV system model in MATLAB SIMULINK is tested under sudden irradiance and cell temperature variations. Incremental Conductance MPPT is used to maximize generated power from the PV system with the help of new adaptive controller to withstand these heavy disturbances. The new adaptive controller is tuned for optimal operation using two different optimization techniques (Invasive weed and Harmony search).Optimization results for the two techniques are compared. .A robustness test is made to check system stability to withstand different random irradiance and cell temperature patterns without failure to track the maximum power point.Finally, a brief comparison is made with a previous literature and the new adaptive controller gives better results

Validated Stability-indicating HPTLC Determination of Baclofen in Bulk Drug, Pharmaceutical Formulations and Real Human Urine and Plasma.

A simple, highly selective and stability-indicating high-performance thin-layer chromatographic method was developed and validated for the analysis of baclofen in bulk powder, pharmaceutical formulations and human urine and in and real human plasma. The method employed TLC aluminum plates precoated with silica gel 60 F254 as the stationary phase. The solvent system consisted of butanol–acetic acid–water (3.0: 0.5: 0.5, v/v/v). This system was found to give compact spots for baclofen (Rf value of 0.54). Densitometric analysis was carried out in the absorbance mode at 238 nm. The linear regression analysis data for the calibration plot showed good linear relationship (r2 = 0.9983) in the concentration range 1.5-7.5 µg per spot. The analytical performance of the method was fully validated, and the results were satisfactory. The limits of detection and quantitation were 0.31 and 1.03 µg per spot, respectively. Baclofen was subjected to acid and alkali hydrolysis, oxidation and photodegradation. The degraded product was well separated from the pure drug. Results indicate that the drug is stable against light and basic conditions. However, additional peaks were observed at Rf value of 0.65 and at Rf value of 0.14 with hydrogen peroxide and hydrochloric acid respectively, indicating that the drug is susceptible to oxidation and acid degradation. The method was applied for the analysis of baclofen in commercial tablets and the results were similar to those obtained using the reference method. As the method could effectively separate the drug from its degradation product, it can be employed as a stability-indicating one. The high sensitivity of the proposed method allowed determination of baclofen in real human urine and plasma

Effect of drilling and wellbore geometry parameters on wellbore temperature profile: Implications for geothermal production

Prediction of the wellbore fluids and formation temperatures is crucial during drilling operation, especially for high temperature wells, such as geothermal applications. This work presents the applications of an improved comprehensive drilling simulator for predicting the wellbore system temperature during the drilling process. A fully transient numerical model of the wellbore temperature is developed for drilling and geothermal production applications. The model describes the dynamic behaviour of the thermal state of the wellbore during circulation and static conditions. The developed model is implemented with the commercial virtual drilling simulator through an application programming interface. This implementation allows the coupling of the thermal model with other physical models, which leads to more advanced and realistic simulations. The model has been previously validated through a direct comparison with field data from geothermal well located in the Hanover area in Germany. The results showed a good agreement between the predicted outlet fluid temperature and the measured one. Furthermore, an analysis of the effect of various parameters on the wellbore system temperature is performed. This analysis showed the impact of these parameters on the wellbore temperature profile including the critical areas such as the casing setting point and bottom hole assembly. This information may lead to enhancing the wellbore stability by monitoring the thermal stresses, especially in high-temperature wells. Moreover, predicting the drill bit temperature can result in increasing the lifetime of the bit by adjusting the operating conditions to keep the bit temperature within the specified range. Based on these results, the enhanced drilling simulator with the transient temperature model showed to be a suitable tool for effective well planning.Document Type: Original articleCited as: Abdelhafiz, M. M., Oppelt, J., Mahmoud, O., Hegele, L. A. Effect of drilling and wellbore geometry parameters on wellbore temperature profile: Implications for geothermal production. Advances in Geo-Energy Research, 2023, 8(3): 170-180. https://doi.org/10.46690/ager.2023.06.0

Endovenous Laser Ablation, Radiofrequency Ablation and Flebogrif versus Conventional Surgery in Treatment of Primary Varicose Vein of the Lower Limb: Prospective Randomized Controlled Study

Background: Endovenous laser ablation (EVLA), radiofrequency ablation (RFA) and mechanochemical ablation (MOCA) of primary varicose vein are thought to minimise postoperative morbidity and reduce work loss compared with the conventional surgical procedure. Objective: To determine, whether endovenous ablation methods (radiofrequency, laser and mechanochemical) have any advantages or disadvantages in comparison with conventional surgery, in the treatment of primary varicose vein. Patients and Methods: This was a prospective randomized study, conducted on forty patients presented at Vascular Outpatient Clinic for management of chronic venous insufficiency. All patients underwent clinical examination and duplex ultrasonography. Ten (10) patients were treated with ligation and stripping of the great saphenous vein (GSV). Ten (10) patients were treated with radiofrequency ablation. Ten (10) patients were treated with endovenous laser ablation. Ten (10) patients were treated with Flebogrif. Results: Compared with conventional surgery, endovenous ablation methods reduced postoperative discomfort and pain, with a lower complication rate after treatment for avoidance of a groin incision and dissection at the saphenofemoral confluence. Cosmetic demands were also better satisfied. Non-controlled clinical trials have shown that the ablation rate of GSV after EVLA is over 90%. However, risks of EVLA, RFA and Flebogrif remain in terms of recanalization and neoreflux via junctional tributaries. Conclusion: RFA, EVLA, and Flebogrif are minimally invasive procedures. Their potential early benefits, by avoiding groin dissection and GSV stripping, have been confirmed by the findings from this trial. Current evidence based on randomized trials consistently demonstrates significant early benefits after RFA, EVLA and Flebogrif in suitable patients with varicose veins

Coping With The Risk Of Interest Rate Fluctuations: The Case Of Kuwait Banks

This study analyzed immunization behavior of a sample of eight Kuwait banks during the 1994 through 2000 period.  The financial market in Kuwait experienced relative stability of interest rates during the analysis period.  The sample banks seemed to adjust their portfolio of assets and liabilities by equating Macaulay duration of assets and Macaulay duration of liabilities.  We could not reject the null hypothesis that there is no difference between average Macaulay duration of assets and that of liabilities.  Our findings indicate that banks in Kuwait are able to match the durations of their assets and liabilities

Jordanian EFL Teachers’ Attitudes towards Dictionaries and their Use in EFL Classrooms

The present study is an attempt to investigate EFL university teachers' attitudes about the importance of the dictionary as an effective learning tool. It also aims at identifying the type of dictionaries preferred by teachers and the types of skills that EFL learners can be improved by the use of the dictionary. Forty EFL teachers responded to a written questionnaire, which included 22 statements. The findings generally revealed that participants do have positive attitudes towards the dictionary as a learning aid. Moreover, the findings revealed that electronic dictionaries are preferred over paper-based ones. However, contrary to our expectations, the findings revealed that although EFL university teachers appreciate the importance of the dictionary, they do not pass this positivity to their students and that they believe using a dictionary is the students' responsibility. The study concluded that by incorporating dictionary usage into classroom practice regularly, EFL teachers will raise their students' awareness of the type of information they can find in the dictionary, how they can use it to serve academic purposes, and become more autonomous learners. Keywords: Communication, dictionary, EFL teachers, pedagogy. DOI: 10.7176/JEP/11-26-07 Publication date:September 30th 202