78 research outputs found

    Optimal statistical method to predict subsurface formation permeability depending on open hole wireline logging data: A comparative study

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    One crucial parameter related to subsurface formations fluid flowing is the rock permeability. Generally, rock permeability reflects the formation capability to transmit fluid. Its significance reflected through several methods existing utilized to predict it, including rock core measurements, empirical correlation, statistical techniques, and other methods. The best and more exact permeability findings are acquired in the laboratory from core plug cored from a subsurface formation. Unfortunately, these experiments are expensive and tedious in comparison to the electrical and electronic survey techniques as wireline well logging methods, for example, not exclusively. The current study compares and discusses different methods and approaches for predicting permeability via wireline logs data. These approaches include empirical correlations, non-parametric statistical approaches, flow zone indicator FZI approach. In this research, we introduced a comparatively new process to predict permeability by the combination of FZI method and the artificial neural networks method. All these approaches are performed using well logs data to the non-homogenous formation, and findings are placed in comparison with permeability from laboratory experiments, which is regarded to be standard. Several statistical criteria, such as ANOVA test and regression analysis, were used to determine the reliability of calculated permeability results

    Kinetic Analysis of Catalytic Dry Reforming of Methane Using Ni-ZrO2/MCM-41 Catalyst

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    This work investigates the kinetics of catalytic dry reforming of methane (CDRM) to produce hydrogen gas using nickel-based catalysts. A new catalyst was prepared, Ni-ZrO2@MCM-41 (MCMZ) and used in the CDRM reaction. The textural, physical, and morphological scans are used to characterize the prepared catalyst. The performance of the newly prepared catalyst in terms of temperature effects and long-term stability is assessed. The reaction activation energy is studied as well. The outcomes of this study revealed that the MCMZ provided the highest conversion values for CH4 and CO2, with 89 and 91%, respectively. The optimum reaction temperature to achieve the highest syngas conversion was 800 °C. In addition, two new models that present CH4 and CO2 conversions for MCMZ as a function of reaction time to predict the rate of catalyst activity were built with very high accuracy. It was found that the activation energy was within the expected limits. Finally, the constants and reaction rate were determined. To conclude, this research creates a new catalyst with high performance to enhance hydrogen gas production from methane with carbon dioxide that contributes significantly to the field of yielding alternative energy sources

    Immunomodulatory, Apoptosis Induction and Antitumor Activities of Aqueous and Methanolic Extract of Calvatia Craniiformis in Mice Transfected with Murine Hepatocellular Carcinoma Cells

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    OBJECTIVES: To evaluate the Immunomodulatory, apoptosis induction and antitumor effects of aqueous and methanolic extracts of Calvatia craniiformis regarding the size of tumour mass, caspase-8 expression and apoptotic index (AI%) in mice transfected with murine hepatocellular carcinoma cell line (H22) as an experimental therapeutic system for human hepatocellular carcinoma.MATERIAL AND METHODS: Forty-eight Balb/C albino mice were transfected in legs with H22 cells. Tumour size was measured twice a week. Caspase-8 protein expression and apoptotic index determination evaluated by Immunohistochemistry.RESULTS: Tumor size significantly differed between the two groups of mice transfected with H22 cells; the first was treated with C. craniiformis aqueous extract (0.3, 0.6, 1.2) mg/kg and the second group was treated with C. craniiformis methanolic extract (0.25, 0.5, 1.0) mg/kg compared with control group. The inhibitory activity of aqueous and methanolic extracts was dose and duration dependent. The size of the tumour mass was reduced up to 87.9% when treated with 1.2 mg/kg aqueous extract and 1 mg/kg for methanolic extract. Caspase-8 expression was increased in a dose-dependent manner among H22 bearing mice treated with C. craniiformis aqueous extract (0.3, 0.6, 1.2) mg/kg. At 0.3 mg/kg, the intensity of expression was strong in (33.33%) and very strong in (66.67%). While at 0.6 mg/kg and 1.2 mg/kg the intensity of expression was strong in (33.33%) and very strong in (100%) with a significant difference (P ≤ 0.001). H22 bearing mice treated with (0.25, 0.5, 1.0) mg/kg C. craniiformis methanolic extract shows increased caspase-8 expression in a dose-dependent manner. At 0.25 mg/kg, the intensity of expression was strong in (33.33%) and very strong in (66.67%). While at 0.5 mg/kg, the intensity of expression was strong in (33.33%) and very strong in (100%). At 1.0 mg/kg, the intensity of expression was strong in (16.67%) and very strong in (83.33%) with significant difference (P ≤ 0.001). AI% of H22 bearing mice treated with C. craniiformis aqueous and methanolic extracts were significantly increased (P ≤ 0.05) compared with the untreated control group. No significant difference was reported in AI% between aqueous and methanolic extracts treated groups.CONCLUSIONS: Extracts of C. craniiformis were highly efficient in tumour growth inhibition, causing a reduction in the tumour size clinically and increase the expression of caspase-8 gene product in tumour tissue, causing increase apoptotic index of H22 cells taken from the legs of inoculated mice leading to loss of legs due to bone necrosis. Antitumor activity of C. craniiformis aqueous, and the methanolic extract was dose and duration dependent

    Comparative estimation of water saturation in carbonate reservoir: A case study of northern Iraq

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    Water saturation is among important petrophysical properties of rock used to assess the initial hydrocarbon in an exploration well. This paper studies five formations from the main limestone carbonate reservoir belong to an exploration field located in the northern part of Iraq. Additionally, we review water saturation models to choose the best one to this exploration field. There are several techniques of water saturation determination applied to estimate reservoir quality. Archie equation is considered one of these techniques; however, applying this model in shale formation gives errors in water saturation estimation. Three different models of water saturation, Simandoux, Indonesian, and Modified Simandoux, were chosen to estimate water saturation in shale beds. Our results demonstrated that the water saturation obtained from the Archie equation is higher than all other models. Furthermore, the Indonesian water saturation model is higher than Simandoux and Modified Simandoux water saturation models. The outcome of the Simandoux and Modified Simandoux were lower than those of Archie and Indonesian models. The accuracy of the water saturation model is evaluated by tends to be close to that of Archie water saturation model is considered negative. The reason is there are no production test results or saturation data from core analysis. The lowest average of water saturation is found in Simandoux and Modified Simandoux models. Depending on water saturation value, the good positive model is modified Simandoux or Simandoux model due to its lowest average value of water saturation. Besides, it can be used for further reservoir studies

    Asphaltene Precipitation Investigation Using a Screening Techniques for Crude Oil Sample from the Nahr-Umr Formation/Halfaya Oil Field

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    Many oil and gas processes, including oil recovery, oil transportation, and petroleum processing, are negatively impacted by the precipitation and deposition of asphaltene. Screening methods for determining the stability of asphaltenes in crude oil have been developed due to the high cost of remediating asphaltene deposition in crude oil production and processing. The colloidal instability index, the Asphaltene-resin ratio, the De Boer plot, and the modified colloidal instability index were used to predict the stability of asphaltene in crude oil in this study. The screening approaches were investigated in detail, as done for the experimental results obtained from them. The factors regulating the asphaltene precipitation are different from one well to another, from the high-pressure-temperature reservoir to surface conditions. All these factors must be investigated on a case-by-case basis. Because the Halfaya oil field is still developing its petroleum sector, modelling, and forecasting the phase behavior and asphaltene precipitation is crucial. This work used crude oil bottom hole samples with an API of equal to 27 from a well in the Halfaya oil field/Nahr-Umr formation to create a thermodynamic model using Multiflash software. The data included the compositional analysis, the PVT data, and reservoir conditions. The thermodynamic model of asphaltene phase behavior was proposed using the Cubic-Plus association equation of state. All the screening techniques' results revealed the presence of an asphaltene precipitation issue (asphaltene unstable), which was confirmed by a thermodynamic fluid model. The aim of this paper is to predict the problem of asphaltene precipitation so that future proactive remedial methods can be developed to decrease the time and expense associated with it

    Knowledge and Preparedness of Dental Practitioners on Management of Medical Emergencies in Jazan Province

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    Medical emergencies are one of the most stressful situations the staff in a dental practice might encounter. The duty of care toward the attending patients obligates suitable preparedness to provide the necessary care if such emergencies ensue. Unfortunately, we found that 22% of the investigated dental clinics had no emergency kit available. Only 38% of the interviewed dentists felt confident to perform CPR, and 18% had no confidence to manage any medical emergency. An MCQ test of 20 questions examining the dentists’ knowledge in medical emergencies was distributed, and the level of knowledge was found to be suboptimal. The average score of the interviewed dentists was 10.87 out of 20. Experience and specialty training had a negligible effect on the level of knowledge

    Coronary Artery Bypass Grafting (CABG) versus Percutaneous Coronary Intervention (PCI) in treatment of left main coronary artery disease

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    BackgroundCoronary artery bypass graft surgery (CABG) has been widely used for left main coronary artery disease (LMCAD). Percutaneous coronary intervention (PCI) has become an option for this condition.AimsTo summarize the current evidence that compare between CABG vs. PCI in regards to ‎cardiac death, stroke, and myocardial infarction.‎Methods We searched randomized trials of treatment of LMCAD with PubMed, Google Scholar, and EBSCO.Results Five randomized studies were retrieved, which compared the efficacy between CABG vs. PCI in treatment of LMCAD.ConclusionPCI may be reasonable management of patients with LM stenosis involving distal bifurcation or with coexisting multivessel disease

    Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

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    Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe
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