Effect of Pipe Rotation on Casing Pressure Within MPD Applications

Well control is one of the most crucial sectors in drilling engineering. Human lives and safety depend on the correct execution of the engineering design. Managed Pressure Drilling (MPD) is a new technology that has recently emerged in the oil and gas industry. It has special well control abilities supported by the RCD to continue drilling or carry operations that involve pipe rotation, while circulating out a gas kick. This thesis examines the effect of pipe rotation on casing pressure profiles within MPD kick circulation application. The analysis was carried on real scale kick experiments. These experiments were carried in a controlled environment that mimicked downhole conditions with a gas influx entering the wellbore. Both water based mud and oil based mud were evaluated. Then, the real scale tests analysis was coupled with the effect of pipe rotation through the application of correlations. The correlations estimate the change in frictional pressure loss in the annuls for non-Newtonian fluids with pipe rotation. A study of the effect of a larger size gas bubble breakage into smaller size bubbles on the maximum anticipated casing pressure is also included in this research. The thesis was divided into three models: (1) dissolved gas model in OBM. (2) single bubble model in WBM. (3) dispersed bubble model in WBM. The first two models studied the effect of frictional pressure changes on the anticipated casing pressure. The dispersed bubble model studies the effect of breaking the gas bubble into many very small bubbles. The practical outcome is to further the precision of the estimation of downhole pressure limits since MPD address narrow fracture-pore pressure window and to find if casing pressure changes would have any effect on the RCD rating selection and if the rotation can be safely conducted

Small Incidental Renal Masses in Adults : Review of the literature

Incidental renal tumours are becoming an important clinical problem that many physicians will need to deal with. A good knowledge of the nature of these tumours and how to manage them is therefore needed. The aim of this paper is to review the literature about incidental renal tumours in adults. Many incidentally discovered small renal tumours (<4 cm) are benign and of low stage, grade and progression potential. The preferred management in young fit patients is open or laparoscopic nephron-sparing surgery. Treatment alternatives include needle-ablative therapies and surveillance in elderly unfit patients. Tumour renal biopsy is encouraged prior to needle-ablative therapy and surveillance. Awareness about incidental renal masses and their management is essential for treating doctors.

Staghorn Calculus in a Horseshoe Kidney

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Adaptive Online Transient Stability Assessment of Power Systems for Operational Purposes

Online stability assessment is an important problem that has not been solved completely yet. The purpose of this research is to tackle online transient stability assessment. Currently, most utility companies use step-by-step integration in order to set protective equipment so that they effectively work for critical contingencies. However, there are times an unforeseen contingency may occur which may cause the system to transit and the protective equipment to misoperate and does not isolate the disturbed part of the system. This research introduces a method that automatically determines a group of generators that participate in system separation and hence transient instability. The method consists of four phases: modeling and simulation, critical machines identification, online transient stability assessment, and critical clearing time calculation. In the modeling and simulation phase, the power system is built and the generators’ rotor angles and speeds are captured. In the critical machines identification phase, the average instantaneous rotor accelerating powers, coherency measures, the during-fault rotor angles and speeds characteristics, and the pre- and post-fault rotor angles are used to identify the Severely Disturbed Group (SDG) of machines. The results of this phase are used to calculate the kinetic energy of the SDG and potential energy of another (or possibly the same) group of generators. Utilization and success of the proposed method will be documented using results from the IEEE 39-Bus test system. Each step of each phase will be demonstrated as needed. The proposed method is compared to step-by-step integration and two direct methods. The suitability of the proposed method for operation will be shown in cases where the Y-Bus matrix and rotor angles and speeds are given. The proof of concept of the proposed method was used in simulating the test system and encouraging results of the simulation were published in ‎[1] and ‎[2]. The proof of concept is the foundation of the method proposed in this dissertation to determine transient stability of large-scale power systems

Adaptive Online Transient Stability Assessment of Power Systems for Operational Purposes

Online stability assessment is an important problem that has not been solved completely yet. The purpose of this research is to tackle online transient stability assessment. Currently, most utility companies use step-by-step integration in order to set protective equipment so that they effectively work for critical contingencies. However, there are times an unforeseen contingency may occur which may cause the system to transit and the protective equipment to misoperate and does not isolate the disturbed part of the system. This research introduces a method that automatically determines a group of generators that participate in system separation and hence transient instability. The method consists of four phases: modeling and simulation, critical machines identification, online transient stability assessment, and critical clearing time calculation. In the modeling and simulation phase, the power system is built and the generators’ rotor angles and speeds are captured. In the critical machines identification phase, the average instantaneous rotor accelerating powers, coherency measures, the during-fault rotor angles and speeds characteristics, and the pre- and post-fault rotor angles are used to identify the Severely Disturbed Group (SDG) of machines. The results of this phase are used to calculate the kinetic energy of the SDG and potential energy of another (or possibly the same) group of generators. Utilization and success of the proposed method will be documented using results from the IEEE 39-Bus test system. Each step of each phase will be demonstrated as needed. The proposed method is compared to step-by-step integration and two direct methods. The suitability of the proposed method for operation will be shown in cases where the Y-Bus matrix and rotor angles and speeds are given. The proof of concept of the proposed method was used in simulating the test system and encouraging results of the simulation were published in ‎[1] and ‎[2]. The proof of concept is the foundation of the method proposed in this dissertation to determine transient stability of large-scale power systems

A Practical Method for Power Systems Transient Stability and Security

Stability analysis methods may be categorized by two major stability analysis methods: small-signal stability and transient stability analyses. Transient stability methods are further categorized into two major categories: numerical methods based on numerical integration, and direct methods. The purpose of this thesis is to study and investigate transient stability analysis using a combination of step-by-step and direct methods using Equal Area Criterion. The proposed method is extended for transient stability analysis of multi machine power systems. The proposed method calculates the potential and kinetic energies for all machines in a power system and then compares the largest group of kinetic energies to the smallest groups of potential energies. A decision based on the comparison can be made to determine stability of the power system. The proposed method is used to simulate the IEEE 39 Bus system to verify its effectiveness by comparison to the results obtained by pure numerical methods

Investor-state arbitration in the Sultanate of Oman: lessons to be learned from the European Union’s approach to the investment court system

The Sultanate of Oman strives to promote economic growth. Foreign investment is one of the most important vehicles for achieving this purpose. The Oman Vision 2040 identifies Foreign Direct Investment as the basis of future economic development. To make Oman a more attractive destination for foreign direct investment, the government has developed and implemented a variety of policies. Modernizing the legal framework governing FDI is central to these policies. Considering this, the question arises as to whether the legislative structure governing investor-state arbitration as a means to ensure that Oman fulfils its obligations to international investors requires modification.Investor-state arbitration has played a crucial role in promoting direct foreign investment. It represents one of the legal procedures for resolving investment disputes between host states and foreign investors. Typically, bilateral investment treaties or multilateral free trade agreements provide for investor-state arbitration as a means of settling potential disputes between host states and international investors. However, investor-state arbitration has been criticised in recent years for being partial, less transparent, and severely impacting the regulatory authority of the host state. This critique has prompted calls for reform of the system for resolving investment disputes. The European Union has undertaken reforms to this system through the investment court system (ICS).This thesis analysis the legislative framework governing investor-state arbitration in Sultanate of Oman and evaluates the need for reform considering mentioned conditions and the Oman's desire to become a more attractive destination for international investments. This necessitates an examination of Oman's national laws pertaining to arbitration and foreign investment in order to identify potential weakness. In addition, bilateral and regional investment treaties, as well as international Conventions related to investor-state arbitration, to which Oman is a signatory, are examined in order to determine Oman's obligations in relation to investor-state arbitration. Furthermore, a comparison is made between ICSID arbitration and the EU's model of the Investment Court System in order to assess the EU's approach to reforming the investment dispute settlement system. This thesis concludes that many aspects of Oman's legal framework governing investor-state arbitration require revision. As a result, the Oman government must adopt an integrated plan to review and modernise this framework in response to Oman Vision 2040 and as part of its broader foreign investment and economic development policy

Cracking the Code: Shedding Light on Accounting Students' Career Intentions - An empirical study

The study aims to assess how a student's plan, perception, and family factors affect accounting students' career intentions. This research delves into the factors that influence accounting students' career intentions and investigates whether these factors evolve as they progress in their studies, ultimately shaping their workplace preferences. The study used a survey questionnaire asked on a 5-point Likert scale to gather primary data from 136 accounting university students studying in Oman. PLS-SEM has been employed in this study to conduct the analysis. The results showed that the determinants of accounting students' career intentions significantly affected students' plans. Likewise, students' perceptions are related considerably to accounting students' career intentions. Hence, the results showed that the p-values of the two independent variables, namely, students' plans and perceptions, significantly support the current study's hypotheses. However, the third variable, family factors, does not impact accounting students' career intention

Assessment of Mothers' Knowledge about Premature infants with cerebral palsy in the Maternity and Children Hospital in Diwaniyah City

Background: Cerebral palsy is one of the most common health problems for premature babies. About 1 to 2 out of every 1,000 babies born at full term will develop cerebral palsy. For babies born at less than 37 weeks of gestation, the risk is twice as high, nearly 100 out of 1,000 live births. Objectives: Assessing mothers' knowledge Premature infants with cerebral palsy. Finding a relationship between demographic information and Premature infants with cerebral palsy.  Methodology: A descriptive questionnaire-based study conducted at mothers from (20 October 2021 to the 17 May 2022). Non probability (purposive) sample of 50 of women's selected from maternity and Child Hospital in Diwaniyah City. The demographic characteristics were obtained through interview with the mothers. The statistical analysis program SPSS was used to analyze the data entered in the form of an excel table and by using the Chi-square for statistical analysis. Results and Discussion: The results of show that there is association between mother' knowledge with their demographic data at p value of less than (0.05). Except item (Occupational) there is no association between mother' knowledge with demographic data at p value of more than (0.05). Conclusion: The study showed that mothers have insufficient knowledge about Premature infants with cerebral palsy. And the factors that effects such as, mother's education, mother's age, and economic level are relation with the mother's knowledge. Recommendations: Organizing educational courses for mothers. Increasing the cultural awareness of mothers and families. Establishing educational programs for pregnant women that play a key role in avoiding complications and reducing the risk of Premature infants with cerebral palsy. Creating recommendations on radio and television that contribute to raising the awareness of mothers. There is a need for more large sample studies to generalize these results, as well as efforts must be adopted by the Iraqi Ministry of Health to establish educational programs

Tuning thermoelectric properties of graphene/boron nitride heterostructures

Using density functional theory combined with a Green's function scattering approach, we examine the thermoelectric properties of hetero-nanoribbons formed from alternating lengths of graphene and boron nitride. In such structures, the boron nitride acts as a tunnel barrier, which weakly couples states in the graphene, to form mini-bands. In un-doped nanoribbons, the mini bands are symmetrically positioned relative to the Fermi energy and do not enhance thermoelectric performance significantly. In contrast, when the ribbons are doped by electron donating or electron accepting adsorbates, the thermopower S and electronic figure of merit are enhanced and either positive or negative thermopowers can be obtained. In the most favourable case, doping with the electron donor tetrathiafulvalene increases the room-temperature thermopower to -284 μv K(-1) and doping by the electron acceptor tetracyanoethylene increases S to 210 μv K(-1). After including both electron and phonon contributions to the thermal conductance, figures of merit ZT up to of order 0.9 are obtained