Continuum and combined continuum-discontinuum analysis of wellbore mechanics and stimulation response

Wellbore drilling and stimulation activities are interlinked processes within the task of borehole construction. Before drilling a well, the initial stress state in the rock can be defined by three principal stresses, with a typical assumption that these consist of the vertical stress (σv), the maximum horizontal stress (σH) and the minimum horizontal stress (σh). After drilling, the stress state changes around the created borehole. The fundamental engineering problem then is to calculate the stresses around the created borehole and/or at the borehole’s wall. Numerous analytical and numerical models exist to estimate the stresses around a circular hole, but these models cannot explain the observed phenomena either in the field or the lab. Attention here is focused on models that are commonly used to predict the stress state around a circular opening. These models do not account for the sequence of the physical processes, leading to an inadequate stress state estimation. This research investigates the 2D classical analytical method, along with a comparison of that approach against numerical methods. This investigation reveals that the models are not equivalent. This is not because of mathematical issues, but is due to the fact that the mechanical systems expressed by these models are not equivalent. The drilling model captures the physics of the real process which makes it possible to explain some phenomena observed in field and laboratory tests. The drilling model approach is applied for several sedimentary rock examples. The combined continuum-discontinuum method reveals its capability in calculating rock failure and deformation that is comparable to some published laboratory drilling tests. Also, the simulation results shed light into the complex fracture growth regime around the wellbore. Drilling and Hydraulic fracture simulation is carried out for Berea sandstone using both the continuum and the combined continuum-discontinuum methods. The results are in good agreement which identifies a practical engineering method for larger models. The fracturing initiates in Mode II (shear) near the circumference of the wellbore aligned with the maximum stress. At later stages, Mode I (tensile) fractures also develop and propagate the fracture parallel to the maximum horizontal stress. This fracturing mechanism continues for as long as the pressure is applied

Airport electrified ground support equipment for providing ancillary services to the grid

The ground handling operations are used in airports for handling activities and processing passengers with the help of specially designed vehicles known as ground support equipment. The ground support equipment (GSE) is being parked after serving a flight until the next flight. The GSE idle duration between flights is depending on the flight schedule and can be turned into a profit source. This paper is presenting a methodology for electrified ground support equipment (EGSE) for providing frequency regulation ancillary services to the grid through an aggregator. The passengers flight schedule is considered to increase the vehicles’ availability to participate in the frequency regulation ancillary services market. The optimization model is formulated to maximize the airport profitability by using aggregation of EGSE in frequency regulation market. The results show that the EGSE provides a significant profit by participating in frequency regulation ancillary service with the use of V2G mode

Optimal annual operational cost of a hybrid renewable-based microgrid to increase the power resilience of a critical facility

With the rapid increment of power outages related to extreme natural disasters such as wildfires and severe storms, microgrids have the potential to enhance resilience locally. Traditionally, grid-connected microgrids are investigated from an economic perspective only, without focusing on resilience solutions benefits during grid interruptions. Hence, the presented work proposes a technical and economic evaluation of an airport grid-connected microgrid consisting of solar photovoltaic (PV), energy storage system, and diesel generator to enhance airport power resilience under different power interruption scenarios. A modified mixed-integer linear programming scheme was introduced to minimize the total annual operating cost of the proposed resilient system. The optimal resilient microgrid components sizing and dispatching were investigated with and without a monetary assigned value for resilience as a service. Moreover, the microgrid survivability during solar performance change was investigated. The possible load increment from electric ground support equipment deployment was considered. The results show that the proposed microgrid can achieve an annual operational cost reduction while ensuring a continuous power supply for all considered outage scenarios. The operational cost saving varies between 20% and 22%. The duration of the outage and critical load level have a higher impact on microgrid sizing and dispatching

A Qualitative Survey Study in Managing Patient Obesity for Exploring Self Efficacy among Saudi General Practitioners

This study aimed at investigate the management of obesity patients for exploring the self-efficacy among Saudi general practitioners in a qualitative survey methodology, by conducting interviews that were recorded digitally and transcribed verbatim by a professional transcription service. DE identified data were transferred into NVivo 10 for data organisation and coding. Data were analysed independently by the researchers and coded using social cognitive theory as a guiding framework. Twenty GPs recruited via a snowball sampling strategy to deliver a pilot of an obesity management program (“The Change Program”) participated in semi structured interviews before commencing the pilot. Of the 20 participating GPs (twelve  males and eight female), ages ranged between 33 and 55, and years working in general practice ranged between 5 and 25. The Interviews were face-to-face and were conducted in June and July of 2017. The study concluded that shifting the frame away from weight loss per se and towards these other goals might therefore allow for a more authentic GP-patient interaction and increase the self-efficacy of both GP and patient for healthy lifestyle changes

Assessment of Bite Forces in Restored Teeth with Different Commonly Used Restorative Materials: A Comparative Study

Objective: To evaluate and compare bite force (BF) in permanent first molars restored with glass ionomer cement (GIC), composite and amalgam, and normal contralateral permanent first molars. Material and Methods: BF was recorded in decayed permanent first molars, which were filled with GIC (n=30), composite (n=30), and amalgam (n=30), and in healthy contralateral first molars (n=90) with Force Transducer Occlusal Force Meter and compared. Results: BF was significantly higher in normal teeth on the contralateral side compared to teeth restored with GIC and composite. However, in patients with amalgam restoration, though it was less compared to that on the contralateral side, it was not statistically significant (p>0.05). Conclusion: Restoring teeth with various filling materials may improve bite force. In the present study, it was found that the teeth restored with amalgam had higher bite forces in comparison to the other restorative materials used. However, it was not comparable to that observed in the normal tooth (control) on the contralateral side

Patients with Inflammatory Bowel Disease and the Higher Incidence of Clostridium Difficile Infection

This study aimed at analyzing the patients with inflammatory bowel disease and the higher incidence of clostridium difficile infection by emphasizing the theoretical review of studies discussing the  inflammatory bowel diseases (IBD), which include Crohn’s disease and ulcerative colitis. And by discussing the treatment of CDI in IBD patients, the diagnosis of CDI in IBD, and the risk factors for CDI in IBD. The study concluded that clinicians should be cautious about the chances of CDI in patients who have an exacerbation of IBD. At times the IBD flare cannot be differentiated from CDI requiring a high degree of clinical suspicion and vouching for early stool testing for toxin assay. When CDI in IBD are established primarily within two days of hospital admission it suggests that a good number of the infection was acquired before admission. CDI should, therefore, be suspected in differentiated diagnosis for intractable IBD patients, because many such patients need not present with a history of antibiotic exposure or hospital admission and may largely be receiving outpatient treatment

Enhanced Recovery After Surgery (ERAS) and the Role of Advanced Hemodynamic Monitoring

This study aimed at exploring the Enhanced Recovery After Surgery (ERAS) as a multi-modality, evidence-based approach to improving the quality of patient care after major surgery and to investigate the effectiveness of the implementation of the ERAS on the outcome measures. Therefore, the problem of this study lies in exploring the Enhanced Recovery After Surgery (ERAS) upon the role of advanced hemodynamic monitoring through examining a sample of (220) patients in two Jordanian hospitals (Jordan Hospital and the Specialty Hospital) undergoing major surgery. The study concluded that the patients had witnessed progressive outcome measures in the Improved Post-operative Morbidity Score (POMS), and the Reduced Length of Stay in Hospital, and the Reduced episodes of harm and surgical complications

Techno-Economic and Environmental Impact Analysis of Large-Scale Wind Farms Integration in Weak Transmission Grid from Mid-Career Repowering Perspective

Repowering a wind farm enhances its ability to generate electricity, allowing it to better utilize areas with high mean wind speeds. Pakistan’s present energy dilemma is a serious impediment to its economic development. The usage of a diesel generator as a dependable backup power source raises the cost of energy per kWh and increases environmental emissions. To minimize environmental emissions, grid-connected wind farms enhance the percentage of wind energy in the electricity system. These wind generators’ effects, on the other hand, are augmented by the absorption of greater quantities of reactive electricity from the grid. According to respective grid codes, integration of commercial onshore Large-Scale Wind Farms (LSWF) into a national grid is fraught with technical problems and inter-farm wake effects, which primarily ensure power quality while degrading overall system operation and limiting the optimal use of attainable wind resources. The goal of this study is to examine and estimate the techno-economic influence of large-scale wind farms linked to poor transmission systems in Pakistan, contemplating the inter-farm wake effect and reactive power diminution and compensating using a range of voltage-ampere reactive (VAR) devices. This study presents a partial repowering technique to address active power deficits produced by the wake effect by raising hub height by 20 m, which contributed to recovering the active power deficit to 48% and so reduced the effects of upstream wind farms. Simulations were conducted for several scenarios on an actual test system modeled in MATLAB for comparative study using capacitor banks and different flexible alternating current transmission system (FACTS) devices. Using the SAM (System Advisor Model) and RETscreen, a complete technical, economic, and environmental study was done based on energy fed into the grid, payback time, net present value (NPV), and greenhouse gases (GHG) emission reduction. The studies suggest that the unified power flow controller (UPFC) is the optimum compensating device via comparison analysis as it improved the power handling capabilities of the power system. Our best-case scenario includes UPFC with hub height augmentation, demonstrating that it is technically, fiscally, and environmentally viable. Over the course of its lifespan, the planned system has the potential to save 1,011,957 tCO2, resulting in a greener environment. When the energy generated annually by a current wake-affected system is compared to our best-recommended scenario, a recovered shortfall of 4.851% is seen, with improved system stability. This modest investment in repowering boosts energy production due to wake effects, resulting in increased NPV, revenue, and fewer CO2 footprints

Chlorhexidine versus Povidone-Iodine for the prevention of ‎Surgical Site ‎Infections: A review.‎

BackgroundSurgical Site Infections (SSIs) are the third most frequently reported health care-associated ‎infection‎ and it remain a major clinical problem despite improvements in prevention, as they ‎are associated with ‎significant mortality and morbidity. Prevention strategies for SSIs are based ‎on reducing the risk of infection by bacteria, So many antiseptic agents are ‎used, the most ‎common one are Chlorhexidine and Povidone-Iodine.‎AimsTo discuss the ‎findings of RCTs that compare Chlorhexidine versus Povidone-Iodine in the prevention of ‎Surgical ‎Site ‎Infections (SSIs).‎Methods This systematic review was carried out, including PubMed, Google Scholar, and EBSCO that ‎examining randomized trials of Chlorhexidine and Povidone-Iodine to summarize the major ‎RCT that compare Chlorhexidine versus Povidone-Iodine in the prevention of Surgical Site ‎Infections (SSIs).‎Results The review included six randomized studies that compare between Chlorhexidine and Povidone-‎Iodine for the prevention of SSIs. The findings showed that many studies prefer using ‎Chlorhexidine over Povidine-Iodine to reduce SSIs, few studies prefer using PVI as antiseptic ‎and other studies reported that there is no significant difference between both. ConclusionMajority of results prefer using Chlorhexidine than Povidone-Iodine‎ as antiseptics but ‎there were few findings prefer ‎PVI and other studies reported that there was no significant ‎difference between using them as ‎antiseptics.

Association of high immunohistochemical expression of minichromosome maintenance 3 with human oral squamous cell carcinoma—a preliminary study

Background: Oral squamous cell carcinoma (OSCC) may arise from premalignant oral lesions (PMOL) in most cases. Minichromosome maintenance 3 (MCM3) is a proliferative marker that has been investigated as a potential diagnostic biomarker in the diagnosis of oral cancer. Objectives: To evaluate the association of MCM3 expression, its clinicopathologic parameters and to identify snuff (also called naswar) as a potential risk factor for changes in MCM3 expression in PMOL and OSCC. Methodology: Immunohistochemistry (IHC) of MCM3 was performed on 32 PMOL, 32 OSCC and 16 normal controls after optimization of IHC methodology. Histoscore (0–300) was used as a scoring system and seven different cut-offs were identified for analyses. Data were analyzed using various statistical tests. Results: Among the seven cutoffs, 40% strong positive cells were found to be a better cut-off as they were associated with many pathological variables (Broder’s grade, Aneroth’s grade, and mitotic activity). The differential MCM3 expression in oral lesions (PMOL and OSCC) was statistically significant (p = 0.03). Moreover, MCM3 expression is raised with increased duration and frequency of snuff use. Conclusion: High MCM3 expression is associated with disease progression and is a potential indicator of malignant transformations from PMOL to OSCC. Moreover, the use of snuff is associated with MCM3 over-expression