Different Acid Systems Interactions with Sand and Ceramic Proppants Used in Gravel-Packed and Fractured Wells

Proppants are solid particles, extensively used in hydraulic fracturing operations. These materials possess specific mechanical strength indispensable in keeping induced fractures open, resulting in up-surged well production. Proppants have different parameters including density, mechanical strength, internal porosity, shape, sieve distribution, and most importantly acid resistance. The acid resistance of the fracturing proppants, defined as the stability and suitability of proppants when they come into contact with different acids, is an important property. Numerous acids are used during the hydraulic fracturing process to remove the scale and clays affecting the fracture conductivity. Inopportunely, these acids adversely affect the proppants already existing in the fracture. The industry measures the acid solubility of proppants according to the API RP 19C/ISO 13503-2 standard. However, it fails to give any guidance on the anticipated final effect of acid dissolution on the mechanical performance of the tested proppants. This study investigates different factors affecting the interactions of different acid systems with sand and ceramic proppants under downhole conditions. Solubility experiments were conducted using translucent and aging cells at temperatures up to 350°F. The effects of varying acid system, temperature, soaking time, static, and dynamic conditions were examined. The supernatant of solubility tests was analyzed with Fluorine Nuclear Magnetic Resonance (19F-NMR) to identify the reaction products. Total key cations’ concentrations were measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Proppants were then analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD) to detect their mineral composition. After performing solubility tests, the residual solids were then dried and analyzed using Scanning Electron Microscopes (SEMs) with Energy Dispersive X-ray Spectroscopy (EDS) capabilities. Moreover, the effects of acid dissolution on the mechanical performance of proppants were also tested using an automated load frame. Experimental results show that monocrystalline sand proppants are soluble in regular mud acid (12.0 wt% HCl, 3.0 wt% HF), with a maximum recorded solubility of 10.0 wt%. Clay-based ceramic proppants are also soluble in mud acid, with much higher acid solubility compared to sand proppants. Proppant pack shows more compaction for clay-based proppants than that of sand proppants prior to and after acid exposure. Bauxitic ceramic proppants have a minimal solubility of 0.5 wt% in 10.0 wt% HCl. The proppant, however, is readily soluble in different mud acid solutions, reaching up to 56.0 wt% dissolution in some extreme cases. The higher solubility of ceramic proppants is attributed to HF attack at the grain boundaries. Understanding the effects of various acids on natural and synthetic proppants will improve production capabilities by promoting the design of acidizing regimens recommended during hydraulic fracturing operations

Assessment of left ventricular function by global longitudinal strain in patients with non-ST elevation myocardial infarction: Comparative study with conventional method

Background: Left ventricular ejection fraction (LVEF) is a strong prognostic parameter in patients with heart disease. The assessment of global longitudinal strain (GLS) from speckle-tracking analysis of 2-dimensional echocardiography has become a clinically feasible alternative to LVEF for the measurement of myocardial function.Objective: The aim of the current work was to compare between GLS speckle tracking echocardiography and Simpson’s biplane methods for assessment of left ventricular function in non-STEMI patients.Patients and methods: This study was carried out in Cardiology Department, Faculty of Medicine, Zagazig University on 44 non‐ST‐elevation myocardial infarction (NSTEMI) patients scheduled for assessment of Left ventricular function by GLS and biplane Simpson method.Result: Mean systolic blood pressure was 122.05±18.37 mmHg. No statistically significant difference in systolic blood pressure was found across GLS groups (P= 0.17). Mean diastolic blood pressure was 73.41±12.00 mmHg. No statistically significant difference in diastolic blood pressure was found across GLS groups (P= 0.35). Mean heart rate was 68.84±7.13 bpm, and a statistically significant difference was found in heart rate across GLS groups (P= 0.039).Conclusion: It could be concluded that GLS speckle tracking echocardiography and Simpson’s biplane methods can be used as alternative different parameters for assessment of left ventricular function in non-STEMI patients

Risk factors of progression of chronic kidney disease patients under conservative treatment

Background: Chronic kidney disease (CKD) is recognized as a major health problem affecting approximately 13% of the US population. Early identification and treatment of risk factors of progression of chronic kidney disease can provide marked benefits later in the term of delaying progression to renal replacement therapy.Methods: The medical chart for 92 CKD patients on regular follow up in low clearance clinic with GFR below 20 ml/min were retrospectively reviewed annually for 4 years regular follow up period. The following variables were recorded for each patient: non-modifiable variables (Age, sex, nationality, BMI, systolic and diastolic blood pressure, smoking status, causes of kidney disease, diabetes status, hepatitis status, medication used (like ACEi/ARBs and Sodium bicarbonate) and modifiable variables which includes: Serum albumin, potassium level, serum bicarbonate level, level of proteinuria, rate of GFR decline (Delta GFR) /year, total cholesterol level and hemoglobin level. Then they were divided into 2 groups according to the endpoint during the follow up period. Group 1 include patients did not start dialysis yet and group 2 which include patients who started dialysis during their regular follow up period.Results: There is no statistically significant differences between the two groups regarding Age , sex, systolic and diastolic blood pressure and Body Mass Index( BMI), serum albumin and haemoglobin levels (p 0.295, 0.317, 0.220, 0.181,0.805, 0.884 and 0.451 respectively). There is no statistically a difference between the two groups regarding serum potassium level and serum total cholesterol level (p 0.515 and 0.517 respectively). Diabetic patients started dialysis earlier than non-diabetics with statistically significant difference between the two groups (p 0.029). The patients who weren’t taking ACEi or ARBs started dialysis earlier than those who were taking (p 0.005), while there was no significant differences between the two groups regarding sodium bicarbonate intake (p 0.256). Low sodium bicarbonate level and severity of proteinuria are of significantly important risk factors for progression of CKD disease (p 0.006 and 0.029 respectively).Conclusions: The most important risk factors for rapid progression are presence of diabetes, severity of proteinuria and low serum bicarbonate level in advanced stages of chronic kidney disease. Early recognition of these risk factors and their correction may retard the progression of CKD, which will delay the need for renal replacement therapy. In addition, ACEI or ARBs intake are almost renoprotective and may delay the rapid progression of chronic kidney disease especially in proteinuric patients.

Evaluation of new scoring system predicting the occurrence of deep infection in open fractures patients

Background: Open fractures of long bones incidence is 11.5 per 100,000 person per year. The management of open fractures had been improved by early adequate surgical debridement and various types of fracture fixation. The Gustilo classification is commonly used for treatment decisions and comparison. Although it had a good prediction power for deep infection but the variability among the inter observer was a problem. Yokoyama et al., 2009 he had advised a new scoring system based on three items of HFS-98 to predicting significant deep infections in open upper and lower extremity fractures.Methods: This study was conducted at Emergency Department Suez Canal University Hospital on 233 Patients with open fractures of long bones from April 2014 till November 2015. The patients were classified according to the criteria proposed by Gustilo classification & Yokoyama’s new scoring system. The relationship between the new score three items were investigated by categorical regression multivariate analysis.Results: In this study, we had 233 Patients with open fractures of long bones. Road traffic accidents were the mechanism of injury in (44.6%). Deep infection was positive in 70/233 patients with Gustilo GI. The cut-off point of application of Yokoyama’s new scoring system was 30, Sensitivity; 63.3%, Specificity; 89%, significant P-value <0.001.Conclusions:The cut-off point of the new Yokoyama’s new scoring application in this study was slit different from the reported applicable values before. This revised scoring system was thought to be useful for predicting deep. Further prospective trial is needed for advising new scoring system.

Evaluation of hepatitis B vaccine responsiveness in ‎hemodialysis and peritoneal dialysis patients

Background: Hepatitis B Virus (HBV) infection is considered as a major cause of liver ‎cirrhosis and hepatocellular carcinoma. Patients with End Stage Renal Disease (ESRD) are a risk group for HBV infection. The vaccine of hepatitis B has ‎been recommended for prevention of HBV infection in ESRD patient ‎especially on renal replacement therapy.  Methods: Eighty seven patients with ESRD on peritoneal ‎dialysis and hemodialysis requiring primary hepatitis B vaccination were ‎enrolled in the study. Each of them received 40 µg of recombinant hepatitis B ‎vaccine in a four-dose schedule. Antibody response was determined by the ‎levels of antibodies to the hepatitis B surface antigen (anti-HBs) after last ‎doses of the vaccination schedule.  Results: We observed three response patterns to the ‎immunizations in all patients after vaccination, the nonresponders (24.7%) ‎never reached the minimum protective titer of 10 mIU/mL, the poor responders (18.5%) had titers between 10 and 100 mIU/mL, and the good responders (56.8%) had antibody titers above 100 mIU/mL. Despite a reduction in anti-‎HBs over time, the good responders did not become unprotected during the ‎observation period, especially those participants who had titers above 1000 ‎mIU/mL after the initial immunization.  Conclusions: We concluded that the immune ‎response of the HBV vaccine was reduced in the HD and PD patients, which ‎need yearly re-evaluation of seroconversion with booster doses of HBV ‎vaccination if needed‎.

Evaluating machine learning models for predictive analytics of liver disease detection using healthcare big data

Liver diseases rank among the most prevalent health issues globally, causing significant morbidity and mortality. Early detection of liver diseases allows for timely intervention, which can prevent the progression of such diseases to more severe stages such as cirrhosis or liver cancer. To this end, many machine learning models have been previously developed to early predict liver diseases among potential patients. However, each model has its accuracy and performance limitations. In this paper, we present a comprehensive comparison of three different machine learning models that can be employed to enhance the prediction and management of liver diseases. We utilize a big data set of 32,000 records to evaluate the performance of each model. First, we implement a preprocessing technique to rectify missing or corrupt data in liver disease datasets, ensuring data integrity. Afterwards, we compare the performance of three machine models: k-nearest neighbors (KNN), gaussian naive Bayes (Gaussian NB) and random forest (RF). We concluded that the RF algorithm demonstrates superior performance in our evaluation, excelling in both predictive accuracy and the ability to classify patients accurately regarding the presence of liver disease. Our results show that RF outperforms other models based on several performance metrics including accuracy: 97.3%, precision: 97%, recall: 96%, and f1-score: 95%

Mathematical formulae for neutron self-shielding properties of media in an isotropic neutron field

The complexity of the neutron transport phenomenon throws its shadows on every physical system wherever neutron is produced or used. In the current study, an ab initio derivation of the neutron self-shielding factor to solve the problem of the decrease of the neutron flux as it penetrates into a material placed in an isotropic neutron field. We have employed the theory of steady-state neutron transport, starting from Stuart's formula. Simple formulae were derived based on the integral cross-section parameters that could be adopted by the user according to various variables, such as the neutron flux distribution and geometry of the simulation at hand. The concluded formulae of the self-shielding factors comprise an inverted sigmoid function normalized with a weight representing the ratio between the macroscopic total and scattering cross-sections of the medium. The general convex volume geometries are reduced to a set of chord lengths, while the neutron interactions probabilities within the volume are parameterized to the epithermal and thermal neutron energies. The arguments of the inverted-sigmoid function were derived from a simplified version of neutron transport formulation. Accordingly, the obtained general formulae were successful in giving the values of the experimental neutron self-shielding factor for different elements and different geometries.Comment: 14 pages, 5 figures, 1 graphical abstract, 73 references, and 2 tables, include improvement of illustration and story-telling writing styl

Role of Elastic Stable Intramedullary Nailing in Diaphyseal Fractures in Children

Background: All femoral or tibial fractures regardless of associated injuries, intramedullary nailing (IMN) has its more advantages in rapid rehabilitation, good effects on the child and his family and strong fixation. Objective: To assess the role of elastic stable IMN in union of diaphyseal fractures of long bones in children. Patients and Methods: A prospective and retrospective analytical study on ten children with isolated femoral or tibial fractures who were admitted to Orthopedic Department, Zagazig University Hospitals. They were divided equally into group I that included 5 patients with femoral shaft fracture managed with IMN and group II, which included 5 patients with tibial shaft fracture managed with IMN. Their mean age was 4.7 years old. Results: When the groups compared, the spica cast group was found to have a shorter duration of hospital stay compared to elastic nail group. The knee range of motion of the spica cast group was found to be better compared to the elastic nailing group. The elastic nailing group was found to have started walking earlier both with and without support. Patients with intramedullary nailing started to walk with aid after one month and  independently after 2 weeks. Patients with spica cast started to walk with aid after 2 months and independently after 12 weeks. Conclusion: None of the available treatment tools to fix diaphyseal long bones fractures in preschool children is perfect because each method has its own set of complications. However, constitute the motive for developing new techniques or changing the design of currently available devices