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Crack Propagation in Pipelines Under Extreme Conditions of Near-Neutral PH SCC

Computers, Materials & Continua 2022年第12期73卷 5315-5329页

作者： Abdullah Alsit Mohammad Alkhedher hasan hamdan Mechanical Engineering Department College of EngineeringAbu Dhabi UniversityAbu Dhabi59911United Arab Emirates

Stress Corrosion Cracking(SCC)process through which cracks occur in a variety of susceptible materials is a result of a combination of residual or applied stresses and *** oil and gas field,buried pipeline steels are made of low-alloy steels with a ferritic-pearlitic structure,such as *** dilute solutions,these materials are prone to SCC *** Near-neutral simulated soil solution(NS4)solution is established to imitate SCC conditions and subsequently became the industry requirement for crack growth experiments in the majority of *** strainassisted active crack pathways are considered while modelling SCC growth as an oxide film rupture and anodic dissolution ***’s been hypothesized that increasing the strain concentration can help with dissolution at the filmfree crack *** research focuses on estimating the SCC crack growth rate under various environmental conditions in oil and gas pipelines using finite element *** simulation is carried out using the J-integral theory in the COMSOL Multiphysics *** are performed to model the crack growth rate(CGR)using slip anodic dissolution(film rupture)*** plastic strain gradient is required to compute the SCC CGR(da/dt).Because the plastic strain located at crack tip increases proportionally to the crack length as it propagates,the CGR increases as the stress intensity factor(SIF)*** crack growth rates increase when constant loads are applied and as the temperature rises,and elevating the cathodic potential has a minimal influence on the propagation rate of cracks but raises the material yield strength and imparts brittle behavior to it.

关键词： Stress corrosion cracking SCC oxide film rupture and anodic dissolution crack growth rate CGR J-integral stress intensity factor SIF

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Self-management of osteoarthritis while waiting for total knee arthroplasty during the COVID-19 pandemic among older Malaysians

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World Journal of Clinical Cases 2023年第29期11卷 7043-7052页

作者： Ahmad Nabil Khairi Mahdzir Sumaiyah Mat Shi Rui Seow Rizal Abdul Rani Muhammad Kamil Che hasan Nor hamdan Mohamad Yahaya Physiotherapy Programme Faculty of Health SciencesUniversiti Kebangsaan MalaysiaKuala Lumpur 50300Kuala LumpurMalaysia Center for Healthy Ageing and Wellness Faculty of Health SciencesUniversiti Kebangsaan MalaysiaKuala Lumpur 50300Kuala LumpurMalaysia Department of Orthopedic&Traumatology Faculty of MedicineUniversiti Kebangsaan MalaysiaKuala Lumpur 56000Kuala LumpurMalaysia Department of Medical Surgical Nursing Kulliyyah of NursingInternational Islamic University MalaysiaKuantan 25200PahangMalaysia

BACKGROUND The study sought to understand the self-management strategies used by patients during the postponement of their total knee arthroplasty(TKA)procedure,as well as the associations between the length of waiting time,pain,and physical frailty and *** study focused on individuals aged 50 years and above,as they are known to be more vulnerable to the negative impacts of delayed elective surgery and *** study hypothesizes that delayed TKR due to coronavirus disease 2019(COVID-19)will bear negative effect in self-management,pain,and physical frailty and function in older *** To investigate the effects of COVID-19 pandemic on self-management,pain,and physical function in older adults awaiting TKA in *** This cross-sectional study has the data of participants,who matched the criteria and scheduled for TKA for the first time,extracted from the TKA registry in the Department of Orthopaedics and Traumatology,Hospital Canselor Tuanku *** on pain status,and self-management,physical frailty,and instrumental activities daily living were also *** linear regression analysis with a significant level of 0.05 was used to identify the association between waiting time and pain on physical frailty and functional *** Out of 180 had deferred TKA,50%of them aged 50 years old and above,80%were women with ethnic distribution Malay(66%),Chinese(22%),Indian(10%),and others(2%)***-two percent of the participants took medication to manage their pain during the waiting time,while 10%used herbs and traditional supplements,and 68%did exercises as part of their osteoarthritis(OA)***-six participants were found to have physical frailty(strength,assistance with walking,rising from a chair,climbing stairs,and falls questionnaire score>4)which accounted for 72%.Increased pain was associated with physical frailty with odds ratio,odds ratio(95%confidence interval):1.46(1.04-2.05).

关键词： Osteoarthritis Total knee arthroplasty Aged COVID-19 Pain Functional performance

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The Effect of Dexamethasone versus Methylprednisolone in the Treatment of COVID-19 Patients in Jordan

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Advances in Infectious Diseases 2023年第3期13卷 508-520页

作者： Jamal Wadi Al Ramahi Nour hasan Amal Matar Ma’en Maher Al-Ali Lara Abdulhadi Dania Abu Kaf Waseem Saadeh Nour hamdan Hassan Abu Khalaf Mohamed Gharaibeh Hanadi Hamadallah Ala’a Bader Mohammad Atout Sae’ed Moh. Mar’I Tamer Alhamed Department of Medicine School of Medicine The University of Jordan Amman Jordan Clinical Pharmacy Al Khalidi Hospital Amman Jordan Department of General Medicine Al Khalidi Hospital Amman Jordan Department of Clinical Medical Sciences Faculty of Medicine Yarmouk University Irbid Jordan Department of Medicine The Specialty Hospital Amman Jordan Department of Anesthesia The Specialty Hospital Amman Jordan Department of Pharmacy Jordan Hospital Amman Jordan Department of Pharmacy The Specialty Hospital Amman Jordan

Background: Previous studies focused on the treatment effect of steroids versus no steroids in treating severe COVID-19 patients, a few studies evaluated outcomes for treating those patients with either dexamethasone or methylprednisolone. Currently, we evaluate the difference in mortality associated with treating COVID-19 patients with dexamethasone versus methylprednisolone. Methods: With a retrospective multicenter study, records were reviewed for the admitted patients with severe COVID-19 during the peak of the severe COVID-19 pandemic. All admitted patients on dexamethasone or methylprednisolone were included. Patients were analyzed as all populations and propensity scores matched patients. Propensity scores were calculated for several confounders by the generalized linear model, and a “greedy” near-neighbor matching algorithm was used. Continuous variables with nonnormal distribution were analyzed by Wilcoxon signed rank test. Chi-squared and Fischer exact test analyzed categorical variables. P-values were adjusted by the Bonferroni method for both data cohorts. Body mass index was in categories. Radiological findings were divided into five categories. The outcomes: mortality, the need for home oxygen therapy, recovery, and residual symptoms on discharge were analyzed by an independent two-sample test for equality of proportions (with Yates correction), and logistic regression analysis. Results: Among the 1128 reviewed records, patients on dexamethasone or methylprednisolone were 1071, and the propensity score-matched patients were 784: dexamethasone 393 and methylprednisolone 391. There was no significant difference in the characteristics of patients between the two steroids (p-value and adjusted p-value > 0.05) for most variables. PSM adjusted a few discrepant variables before analysis. The outcome of the unmatched patients demonstrated dexamethasone benefit in the need for home oxygen therapy ( 0.05). However, matched patients demonstrated significantly low

关键词： Dexamethasone Methylprednisolone COVID-19 Mortality Home Oxygen COVID-19 Recovery

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Predicting Rainfall Using the Principles of Fuzzy Set Theory and Reliability Analysis

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American Journal of Computational Mathematics 2013年第4期3卷 337-348页

作者： Mahbub hasan Salam Md. Mahbubush Khan Chandrasekhar Putcha Ashraf Al-hamdan Chance M. Glenn College of Engineering Technology and Physical Sciences Alabama Agricultural and Mechanical University Normal USA Department of Civil & Environmental Engineering University of Alabama Huntsville USA Department of Civil and Environmental Engineering California State University Fullerton USA Department of Civil Engineering Alabama Agricultural and Mechanical University Normal USA Department of Mathematics Alabama Agricultural and Mechanical University Normal USA

The paper presents occurrence of rainfall using principles of fuzzy set theory and principles of reliability analysis. Both the abstract and the rest of the paper are discussed from these two points of view. First, a fuzzy inference model for predicting rainfall using scan data from the USDA Soil Climate Analysis Network Station at Alabama Agricultural and Mechanical University (AAMU) campus for the year 2004 is presented. The model further reflects how an expert would perceive weather conditions and apply this knowledge before inferring a rainfall. Fuzzy variables were selected based on judging patterns in individual monthly graphs for 2003 and 2004 and the influence of different variables that caused rainfall. A decrease in temperature (TP) and an increase in wind speed (WS) when compared between the ith and (i ? 1)th day were found to have a positive relation with a rainfall (RF) occurrence in most cases. Therefore, TP and WS were used in the antecedent part of the production rules to predict rainfall (RF). Results of the model showed better performance when threshold values for 1) Relative Humidity (RH) of ith day;2) Humidity Increase (HI) between the ith and (i ? 1)th day;and 3) Product (P) of decrease in temperature (TP) and an increase in wind speed (WS) were introduced. The percentage of error was 12.35 when compared the calculated amount of rainfall with actual amount of rainfall. This is followed by prediction of rainfall using principles of reliability analysis. This is done by comparing theoretical probabilities with experimental probabilities for the occurrence of two main events, namely, Relative Humidity (RH) and Humidity Increase (HI) being in between specified threshold values. The experimental values of probability are falling in between μ ? σ and μ + σ for both RH and HI parameters, where μ is the mean value and σ is the standard deviation.

关键词： Fuzzy Sets Prediction Reliability Rainfall Water Resources

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