Drillstring Vibration Analysis in Extended Reach Drilling (ERD) using WELLPLANTM

Oil and gas industry always aims efficient service with optimal expenses. This final year project, aiming to deal with one of the most important parameters, that has tremendous impact on drilling operations’ time and cost. This parameter as mentioned above on the topic is a Drillstring Vibrations. While drilling, Drillstring Vibration causes premature drillstring components and bit failure [8], and is a waste of drilling energy. To increase drilling efficiency, drillstring vibrations need to be monitored and analyzed and the optimum drilling parameters and practices need to be achieved as a well is being drilled. This results in a reduction in the drillstring failures and the amount of time spent tripping and/or fishing, and an increase in both bit life and drilling rate. Drillstring dynamics is one of the most important limiting factors in extended reach drilling. This is because, long sections of the drillstring lie on the low side of the wellbore while rotating. When the rotary speed exceeds a critical threshold the drillstring starts to snake, sliding up and down the borehole wall [1]. If rotated further beyond the threshold speed, the drillstring will eventually start to whir which can cause severe damage to string components after only a short period of time [1]. Therefore, the main scope of the project, considering the earlier mentioned issues, a WELLPLAN software (Critical Speed Module) used. The project mainly dealt with drillstring, axial stress, bending stresses and torsional oscillations known as stick-slip motion of the bit. Besides the WELLPLANTM software, a matlab M.file was developed that uses some predetermined equations to estimate the critical drillstring vibrations, and critical operational speed taking into account the weight on bit, BHA length and rock compressive strengt

Time-Uncertainty Analysis by Using Simulation in Project Scheduling Networks

Risks are inherently present In all construction projects. Quite often, construction projects fail to achieve their time quality and budget goals. Risk management is a subject, which has grown in popularity during the last decade. It is a formal orderly process for systematically identifying, analysing and responding to risks associated with construction projects so as to reduce the effects of these risks to an acceptable level. Risk analysis is primarily concerned with evaluating uncertainties. The purpose of risk analysis is to enable a decision-maker to take an appropriate response in advance against a possible occurrence of a problem. In this study, Monte Carlo simulation as a tool of risk analysis was used. The merge event bias as one of the essential problems associated with PERT is discussed, along with models and approaches developed by other researchers, namely, Probabilistic Network Evaluation Technique (PNET algorithm), Modified PNET, Back-Forward Uncertainly Estimation procedure (BFUE) and concept based on the robust reliability idea. These developed approaches are more reliable in planning construction projects compared to PERT because they attempt to handle the merge event bias problem. In addition, this study demonstrates a number of benefits. the most significant among them being that: (1) Formal risk management tec1miques are rarely used in construction. Dealing with risk management in construction is now essential for minimizing losses and to enhance profitability. (2) It is very dangerous to rely only on PERT/CPM conventional techniques in scheduling projects. (3) To use floats, as stated by traditional resource allocation method, is not practicable. (4) For a project network, the likelihood completion date of a project is exactly equal to the product of the probabilities of each path, separately, with respect to a project completion date. Using simulation now validates this statement. (5) The\ud computation error of a project likelihood completion date is less than 10 percent if a path of a float greater than twice the larger standard deviation of this mentioned path and the critical path is dropped from the calculation, and (6) An effective risk response framework is introduced to help contractors systematically manage the risk in scheduling their projects

The Effect of HIV Education Program on Changing the Attitude of Secondary School Students Towards HIV/AIDS Sufferers Khartoum State (2014)

HIV/AIDS seriously affects adolescents throughout the world. One-third of all currently infected individuals are youth ages 15 to 24, and half of all new infections occur in same age youth. This is an Interventional Quasi study, aimed to assess the effect of health education program of Human Immune -Deficiency virus on changing attitude towards HIV and AIDS among secondary school students in Khartoum state. Five hundred students were enrolled by using multi stage random sampling, the study was done in three phases: phase one used questionnaire of 32 questions. Phase two was implementing the Sudanese National Aids Program (SNAP'S) which is a health education program in secondary schools alongside the curriculum for students in the selected secondary schools for 8 months. Phase three was Re- Evaluation by the same questionnaire used in phase one. The study revealed that few students were willing to care of a family member or friend who suffers with AIDS (25.6%) in the pre-test however the percentage increased to  (79.2%)  after intervention, (42.6%)  thought that HIV positive people should not be allowed to mix with people at mosque or church , the percentage decreased to (39.2%) after the intervention. 63.8% of students said that a teacher who is HIV positive should not be allowed to continue teaching in their school, while only (86.2%) of the students changed their mind after intervention. Also prior to intervention (27.6%) of the students accepted sharing same class with HIV infected student while (50.0%) agreed after the intervention. The study concluded that education intervention program was effective and statistically significant in the Improvement of students' attitude towards HIV/AIDS positive (P value= 0.001). معظم اصابات فيروس  مرض نقص المناعة المكتسب تحدث وسط الشباب من عمر 14-24 سنه هذه دراسه تدخليه تهدف الى تقييم أثرتدريس كتيب البرنامج القومى السودانى للايدز للتثقيف الصحى على سلوك  عينة من طلاب المدارس الثانوية بولاية الخرطوم تجاه  المصابين بالفيروس أو مرضى الأيدز و التى اشترك فيها (500) طالب تم اختيارهم عشوائيا بطريقة التعدد المرحلى . نفذت الدراسة على ثلاثة مراحل : المرحلة الأولى تم فيها جمع المعلومات بواسطة استبيان مكون  من(32) سؤال , ثم مرحلة التدخل عن طريق تدريس الذى وضع بواسطه البرنامج السودانى القومى للايدز  لمدة سته اشهر, ثم المرحلة الثالثة و التى جمعت فيها البيانات بنفس الاستبيان الأول . توصلت الدراسة الى النتائج الآتية: 25.6% من الطلاب كانوا موافقين على رعاية مريض ايدز ينتمى الى الأسرة قبل التدخل بينما ارتفعت النسبة الى 79.2% بعد التدخل . 42.2% رأوا أن المصاب بالفيروس لا يجب ان يختلط بالناس فى المسجد و قد نقصت النسبة بعد التدخل الى 39.2%. 63.8% من الطلاب قبلوا بتلقى الدراسة من معلم مصاب بالفيروس قبل التدخل و قد ارتفعت النسبة الى 86.2% بعد التدخل. كما لم يمانع 27.6% منهم على وجود زميل لهم بالفصل مصاب بالفيروس قبل التدخل  و ارتفعت النسبه الى 50.0% بعد التدخل . خلصت الدراسة الى أن منهج التثقيف الصحى للطلاب ذو أثر بالغ احصائيا  فى تحسين إتجاهات طلاب المدارس الثانوية  تجاه المصابين بفيروس نقص المناعة المكتسب أو تجاه مرضى الايدز

Reconstruction Algorithm for Sound Speed Distribution in the Female Breast

In the last few years, Ultrasound Computed Tomography (USCT) techniques has become an attractive and hot research area. Herein, we present a robust iterative USCT reconstruction algorithm, which based on bent ray theory. The object to be imaged is encircled by uniformly distributed transduc-ers, whereas one transducer acts as a transmitter and the remains work as receivers. The travel-time meas-urements can be used to estimate the sound speed distribution by solving a nonlinear system of equations. Our proposed scheme is based on the straight ray approximation, which is valid for breast ultrasound tomographic imaging. On this basis, we have formulated a cost function that defines the difference be-tween the measured first arrivals and those calculated for a given velocity model in the least squares sense. Then, the sound speed image can be obtained by finding the best solution which minimize this dif-ference. Our method is able to resolve very fine details even in very complex structured objects. The pre-sented results approve the accuracy and robustness of our approach for breast screening application

Minimal Spin-3/2 Dark Matter in a simple ss-channel model

We consider a spin~-~3/2 fermionic dark matter candidate (DM) interacting with Standard Model fermions through a vector mediator in the $s$-channel. We find that for pure vector couplings almost the entire parameter space of the DM and mediator mass consistent with the observed relic density is ruled out by the direct detection observations through DM-nucleon elastic scattering cross-sections. In contrast, for pure axial-vector coupling, the most stringent constraints are obtained from mono-jet searches at the Large Hadron Collider.Comment: 8 pages, 5 figures, Version accepted for publication in EPJ

Gauge higgs unification in extra dimensions and spin-3/2 dark matter

A Thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in ful llment of the requirements for the degree of Doctor of Philosophy. April 2018In this thesis we discuss various gauge group structures in the gauge-Higgs uni - cation models. The rst group we considered was a toy SU(3) model, where it is possible to have the uni cation of gauge and top Yukawa couplings, which is an attractive feature of gauge-Higgs uni cation models in extra-dimensions. This feature is usually considered di cult to obtain based on simple group theory analyses. We reconsider several minimal toy models calculating the renormalisation group running at one loop. Our results show that the gauge couplings unify asymptotically at high energies, and that this may result from the presence of an UV xed point. The Yukawa coupling in our toy models is enhanced at low energies, showing that a genuine uni cation of gauge and Yukawa couplings may be achieved. Furthermore, the evolution of the Cabibbo-Kobayashi-Maskawa matrix elements, the Jarlskog invariant and the quark mixings are derived for the one-loop renormalisation group equations in a ve-dimensional models for an SU(3) gauge group compacti ed on an S1=Z2 orbifold. We have assumed that there is a fermion doublet and two singlets located at the xed points of the extra dimension, which pointed to some interesting phenomenology in this toy model. We then explicitly test in a simpli ed 5-dimensional model with SU(5), SU(5) U(1)0 and G2 gauge symmetries, the evolution of the gauge couplings, by assuming that all the matter elds are propagating in the bulk, and consider orbifolds based on Abelian discrete groups which lead to 5-dimensional gauge theories compacti ed on an S1=Z2. The gauge couplings evolution is derived at one-loop level and used to test the impact on lower energy observables, in particular the Weinberg angle. For our numerical calculations we have assumed that the fundamental scale is not far from the scope of the Large Hadron Collider, where we choose the compacti cation radii to be the following benchmark values: 1TeV, 4TeV, 5TeV, 8TeV, 10TeV, 15TeV and 20TeV. As these gauge-Higgs uni cation models can also contain many additional particles, we sought to use these particles as dark matter (DM) candidates. As many studies have already been done on various spin DM particles, we chose to focus on the more exotic spin-3/2 fermionic DM. We have allowed interactions with standard model fermions through a vector mediator in the s-channel in our rst considerations. An interesting feature of the spin-3/2 nature of the standard model particles is that there exists a minimum value of the DM mass for a given coupling and mediator mass, below which the decay width of the mediator exceeds the mediator mass. We nd that for pure vector couplings almost the entire parameter space in DM and mediator mass is consistent with the observed relic density, and is ruled out by the direct detection observations through DM-nucleon elastic scattering cross-section. In contrast, for pure axial-vector coupling, the most stringent constraints are obtained from mono-jet searches at the Large Hadron Collider. We have also considered a spin-3/2 fermionic DM particle interacting with the standard model quarks through the exchange of a charged and coloured scalar or vector mediator in a simple t-channel model. It is found that for the vector mediator case almost the entire parameter space allowed by the observed relic density is already ruled out by the direct detection LUX data. There are no such bounds which exist on the interaction mediated by scalar particles. Monojet + missing energy searches at the Large Hadron Collider provide the most stringent bounds on the parameters of the model for this case. The collider bounds put a lower limit on the allowed DM masses. These studies have shown a variety of particle phenomenology beyond the standard model, where such models can be constrained from both collider and astrophysical data.MT 201

Spin-3/2 dark matter in a simple tt-channel model

We consider a spin-3/2 fermionic dark matter (DM) particle interacting with the Standard Model quarks through the exchange of a charged and coloured scalar or vector mediator in a simple $t$-channel model. It is found that for the vector mediator case, almost the entire parameter space allowed by the observed relic density is already ruled out by the direct detection LUX data. No such bounds exist on the interaction mediated by scalar particles. Monojet + missing energy searches at the Large Hadron Collider provide the most stringent bounds on the parameters of the model for this case. The collider bounds put a lower limit on the allowed DM masses.Comment: Published EPJC versio

Metrological Model for Inspection and Evaluation of Medical Devices

In this paper a metrology model is proposed for inspection and evaluation of medical devices, which provide cost-oriented re-diagnosis rate of non-accuracy of the results. This work focuses on the current situation of medical devices in military hospital and Khartoum hospital, by applying the statistical methods such as the mean, frequencies, percentages and independent T – test. Results obtained by the model reflect the state of medical devices in hospitals. However, the average percentage of standards inspection and evaluation of medical devices which reached at military hospital is (46.8%) and Khartoum hospital is (47.9 %). While, the ratio required to ensure the efficiency of medical devices scientifically more than (95%) which helps in diagnosis, treatment, monitoring of patients to provide the best healthcare services