bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metallurgy Selection of Tubing in Sucker Rod Pump Wells Plagued with Pitting and Abrasion Issues
Authors: Uniyal Rishabh , Bansal Rajeev , Jaruhar Suman Kumar , Biswas Sudipta , Devshali Sagun , Dogra Priyanka 
Published: June 2021

Abstract
Analysis of tubing failure of SRP wells with respect to uniform corrosion, pitting and mechanical abrasion has been carried out. The primary objective includes the identification of root cause of failure and suggesting alternate metallurgy.
Many wells in an onshore field in ONGC were facing the acute problem of general corrosion, pitting and rod-tubing wear. The methodology for carrying out the study consists of a Failure Analysis of a retrieved sample of the failed tubing from one of the affected wells. This included a thorough visual inspection, Scanning Electron Microscope analysis and X-Ray Diffraction analysis. The results of these tests were backed up by software simulation in Honeywell Predict. Metallurgy selection involved multiple exhaustive simulation runs in Honeywell Software Socrates which was corroborated by relevant oilfield standards as well as literature available on the subject matter.
Based on the failure analysis and simulation runs, it was concluded that besides the issue of uniform corrosion and pitting, many of the affected wells are also facing the problem of tubing failures due to abrasion and mechanical wear. It is pertinent to note that the major contributor of the frequent tubing failures in the candidate wells selected for the study were pitting and corrosion. Nevertheless, Abrasion always remains a key threat to the tubing string integrity in rod-pump wells. Therefore, the existing tubing metallurgy of N-80 grade Carbon Steel was deemed inadequate in the absence of reliable corrosion inhibitor continuous dosing facilities. A tubing metallurgy that takes care of both pitting corrosion as well as abrasion and mechanical wear was sought. UNS 41426/41427 or the modified version of 13 Chrome, commercia lly known as Super Martensitic 13 Chrome, are available in 95 ksi and 110 ksi grades. These grades have a maximum hardness of 28-32 HRC which is substantially high compared to L-80 13 Cr (maximum 23 HRC). Also, as this alloy has 4-6% Nickel, it provides added protection against uniform corrosion as well as pitting and hence was recommended.
The paper specifically analyses tubing failure in Sucker rod-pump wells due to corrosion, pitting and abrasion. After exploring various viable options, adequate tubing metallurgy has been recommended that should take care of corrosion, pitting as well as mechanical wear problems.
Discussion of Oxygen Threshold Level for Corrosion Management in Seawater Injection Systems
Authors: Ferrari Jean Vicente 
Published: June 2021

Abstract
Generally, in water injection systems, oxygen levels starting from around eight ppm are deoxygenated to below 50 ppm, following international standards' guidelines. This work aims to discuss the impact of such a magnitude value of oxygen contamination on steel corrosion in seawater injection systems by analysing theoretical polarisation curves and results from published works with different approaches. Corrosion models consider mass-transfer controlled diffusion of oxygen to predict the maximum steel corrosion rate, which depends on the oxygen limiting current, which in turn is strongly influenced by flow velocity. The effect of free chlorine on corrosion in seawater injection systems has also been considered and included in an oxygen equivalent parameter. In such systems, where oxygen reduction is the key cathodic reaction, the corrosion process may be under cathodic activation control, independent of flow at higher velocities or when erosion-corrosion begins. In this work, theoretical polarisation curves were constructed by using published oxygen and chlorine cathodic limiting currents (iLc) on carbon steel and a noble metal electrode, respectively. Aerated (200 ppb and 9000 ppb of oxygen) and deaerated conditions (50 ppb of oxygen) and the presence of 300 ppb of chlorine were applied to the assumed exchange current densities (io). Neutral (pH 7) and acid (pH 4) conditions (considering the presence of CO2) were also assumed to be at room temperature and pressure. Since the corrosion rate in lower oxygen concentrations (ppb order of magnitude) may result in corrosion rates of the same order of magnitude than in higher oxygen concentrations (ppm order of magnitude) when comparing and analysing results from experimental, semi-empirical or mechanistic approaches, it is necessary to weigh up the effects of both steel surface (bare or scaled/corrosion products) and flow. At oxygen concentrations below 200 ppb and under acid conditions, the contribution of H+ reduction on corrosion rate starts to be higher than oxygen reduction, mainly in the absence of chlorine.
Crevice Corrosion in Oxygen Scavenger Injection System
Authors: Keserovic Amela , Birketveit Øystein 
Published: June 2021

Abstract
Biulfite-based oxygen scavengers (OS) have been traditionally used in oilfields to reduce corrosion resulting from dissolved oxygen. Recent experience with a leakage in OS-A oxygen scavenger injection system has shown that the same production chemicals in neat form can cause corrosion themselves, specifically – crevice corrosion.
In this paper a tendency of three bisulfite-based oxygen scavengers to initiate crevice corrosion on 316 stainless steel (316 SS) was evaluated by means of long-term exposure tests and short-term electrochemical techniques; cyclic potentiodynamic polarization (CPP) and Tsujikawa–Hisamatsu electrochemical method (THE). The testing was performed at ambient temperature and pressure to mimic the topside injection system conditions. The tested oxygen scavengers differed in bisulfite concentration (OS-A, 341 g/L; OS-B, 328 g/L; OS-C, 750 g/L) and pH (pH 3, 6 and 5, respectively). Two 316 SS coupons were attached together using elastomer O-rings to simulate steel-to-steel crevice between. The surface of the coupons was examined at 50x magnification after the test termination.
The results presented herein showed that 30-day long exposure tests were not long or aggressive enough to provide information about the corrosivity of the chemicals in terms of crevice corrosion. Instead, the combination of short-term electrochemical techniques proved to be useful in explaining a possible cause of the leakage in OS-A injection system and allowed ranking of the products based on their tendency to initiate localized corrosion.
Improving Mean Time Before Failure MTBF in Rod Pumped Wells by Analyzing Corrosion Barriers
Authors: Chanchlani Kuldeep , Khanduja Nikhil , Gunwant Deepak 
Published: June 2021

Abstract
Subsurface pumps and production tubulars are one of the important means for the production of crude oil from the subsurface to the surface installation in mature oil and gas fields. The health of downhole pumps and tubulars is severely endangered by the electrochemical deterioration, which will be discussed in the context of the working environment. The extent of damage caused to sucker rods traversing down to the pump for Rod Pump wells is discussed. A self-improved corrosion management process is brought out by briefly discussing inspection, monitoring, and mitigation methods. The corrosion decision tree is critical in analyzing corrosion failure and a unique method for risk assessment. Qualitative and Quantitative Mean Time Before Failure (MTBF) analysis were executed for rod pumped wells. An action plan was prepared to mitigate corrosion and/or friction-related failures. Yearly workover trend of workovers reduced as a result of action plan executed.
Oil and gas companies use a certain percentage of their operational expenditure to protect against corrosion on average. Material failure, performance improvement, cost, and safety are critical for corrosion control. Inspection and monitoring techniques are not sufficient enough to estimate future performance. By assimilating inspection, monitoring, mitigation, and prediction techniques, an extensive corrosion-management program can be developed. Remedial actions taken subsequently can then be followed strictly to counterwork against the effects of corrosion barriers. Mean Time Before Failure (MTBF) can be significantly improved by following this methodology as discussed in the action plan.
Go-gauging and inhibitor wash for tubular, is the recommended method for operators in extracting subsurface oil from a corrosive environment. Corrosion decisions tree assesses the risk involved in corrosion, and corrosion management is an arrangement of barricades to impede material failure. MTBF analysis can be beneficial to the operators to understand the reason behind the failure of subsurface pumps and/or downhole production tubing.
Application of Benzotriazole Corrosion Inhibitor in Synthetic-Based Drilling Fluid and its Overall Impact in Improving Drilling Fluid Functionality
Authors: Xionghu Zhao , Egwu Saviour Bassey , Jingen Deng , Liujie Miao 
Published: June 2021

Abstract
The effect of corrosion inhibitor Benzotriazole on synthetic-based mud system was studied. Rheological performance of the benzotriazole enhanced synthetic-based fluid system was studied and compared against the base mud. To study its effect on dynamic wellbore conditions, different drilling fluid compositions were placed in a hot rolling oven for 16 hours at temperatures 150 °C and 170°C and the effect of temperature on mud properties were studied. Tests carried out include rheological test (before and after hot rolling), filtrate pH, lubricity test, and fluid loss test. The corrosion penetration rate was studied using the weight loss method. Based on experiment results, the synthetic-based mud system which comprised of benzotriazole displayed a reduction in coefficient of friction up to 95.93%.
At ambient condition, optimal ratio of mineral oil:benzotriazole (M:B) which gives best lubricity performance on synthetic-based mud system is 80:20. This leads to improved corrosion inhibition and lubricity of the synthetic-based fluid by reducing the coefficient of friction up to 90.13%. Increased temperature led to further decrease in coefficient of friction with a % torque reduction of 95.93 displayed by the 80:20 ratio M:B mud composition at 170 °C. Significant alterations of the mud composition rheological and fluid loss parameters before and after exposure to high temperature in hot rolling oven were not observed. pH values were maintained ≥7 at the dynamic conditions highlighting solubility of the formulated fluid composition and absence of contaminants which can pose significant threats to the rates of corrosion in drill pipes. Increasing the concentration of Benzotriazole led to a reduction in corrosion rate. However, as the temperature effect increased, the corrosion rate elevated. Based on results from this investigation, it was concluded that Benzotriazole can be applied as a corrosion inhibitor in a synthetic-based drilling fluid system as an alternative corrosion inhibitor without significant alteration of the base mud properties. Benefits of this will be the optimization of extended reach well drilling operations due to excellent lubricity performance, corrosion rate reduction, compatibility with HPHT wellbore condition and fluid loss control.
Possible Missing Link in CO2 Corrosion Prediction
Authors: Gunaltun Yves 
Published: June 2021

Abstract
CO2 corrosion prediction models predict a general corrosion rate, but field failures are due to localised CO2 corrosion. That is why predicted corrosion rates are correlated to a corrosivity level. These models generally consider that the corrosion rate remains, after the initiation period, unchanged as long as operating and/or production parameters remain unchanged. However, 25 years of field experience and also some recent research results confirmed that after an initial phase of high corrosion rates, the CO2 corrosion rates may significantly decrease with time forming flat-bottom large corrosion features (mesa corrosion) and stabilise. Depending on the corrosivity level the time needed for the stabilisation would be up to about 12 months. To be noted that the stabilization has been known since 2003-2004. It was first used in 2005 for the development of two gas fields with success. In 2008, it was used for the prediction of the remaining life of gas pipelines transporting very corrosive wet gas. The use of costly CRA / cladded pipes was avoided. Gunaltun Y. and call. made the first publication about the importance of the stabilization on the remaining pipeline service life in 2009. Then, possible mechanisms of stabilization were published by Gunaltun Y. in 2012 and Gunaltun Y. and call. 2013. In the present paper the field experience, the research results and the mechanisms leading to stabilisation are discussed in detail and summarised. The main driving force is the galvanic action between anodic and cathodic zones. The clustering of corrosion features completes the process of stabilisation. Re-initiation of corrosion, after stabilisation, has not been observed neither in the laboratory nor in field. The reasons why stabilisation is a non-reversible process are also explained in detail. The conclusions are integrated in the general understanding of CO2 corrosion mechanism. Then a new method is proposed to complete the corrosion prediction approaches used by the industry. Even though some research is still needed to validate the impact of some parameters involved in the stabilisation process, the stabilisation concept is now mature enough for including it in the prediction models. It is very likely that stabilisation is one of the missing links in CO2 corrosion prediction chain.
TRIAD: a transposition-based approach for gene mutagenesis by random short in-frame insertions and deletions for directed protein evolution
Authors: Emond Stephane , Hollfelder Florian 
Published: June 2021

Abstract
Insertions and deletions (InDels) are among the most frequent changes observed in natural protein evolution, yet their potential has hardly been harnessed in directed evolution experiments. Here we describe the standard protocol for TRIAD (Transposition-based Random Insertion And Deletion mutagenesis), a simple and efficient Mu transposon mutagenesis approach for generating libraries of single InDel variants with one, two or three triplet nucleotide insertions or deletions. This method has recently been employed in three published examples of InDel-based directed evolution of proteins, including a phosphotriesterase, a scFv antibody and an ancestral luciferase.
Healthcare student’s perception towards e-learning approach during COVID-19 pandemic: A study protocol
Authors: Kannao Vaidehi , Naqvi Waqar M. , Arora Sakshi P. 
Published: June 2021

Abstract
Introduction: The outbreak of the COVID-19 pandemic has shaken humanity to its core. In the physical distancing, span of vaccination is the most remarkable protective measure for outspreading disease. Shutdown of universities and schools has made education undetermined at every levels. During this pandemic, the demand for a well-trained generation of upcoming doctors is greater than it has ever been in our living memory. Due to the COVID-19 pandemic, medical education now requires mandatory e-learning. However, in emerging countries like India, the scope of the challenges remains unexplored (with wide socioeconomic and cultural diversity). At this critical juncture, we want to see if online teaching approaches for medical students are as appropriate, beneficial and accessible.Method: A cross-sectional study will be conducted in Ravi Nair College of Physiotherapy, India, with a sample size of 150 students aged 18 to 30 years with the study duration will be 6 months. The participants will be asked to fill the questionnaire through an electronic survey in Google Forms. And after completion of the study result will be calculated by systemic data analysis.Discussion: During the COVID-19 pandemics, this study will assess the approach of healthcare students in perceiving online learning. The research will help understand more about their views on e-learning as a device for assisting their education throughout the COVID-19 pandemic. As a result, a better understanding of this may aid in the formulation of future medical school curricula.The Institutional Ethical Clearance reference number for this study is RNPC/IEC/2020-21/0014.
The ISAD (Infraslow Neurofeedback for Anxiety and Depression) Study: A Protocol for a Trans-Diagnostic, Randomized, Double-Blind, Sham-Controlled, Dose-Response, Parallel-Group Trial
Authors: Perez Tyson , Glue Paul , Adhia Divya B , Smith Mark , De Ridder Dirk , Zeng Jiaxu , Dillingham Peter , Niazi Imran 
Published: June 2021

Abstract
Background: The core intrinsic connectivity networks (ICNs), encompassing the default-mode network (DMN), salience network (SN) and central executive network (CEN), have been shown to be dysfunctional in individual’s with internalizing disorders (IDs; e.g. major depressive disorder, MDD; generalized anxiety disorder, GAD; social anxiety disorder, SOC). As such, source-localised electroencephalogram neurofeedback (EEG-NFB) therapy targeting key cortical nodes within these networks has the potential to reduce symptoms associated with IDs and restore normal core ICN function. We intend to conduct a transdiagnostic, randomized, double-blind, sham-controlled, dose-response, parallel-group trial of standardized low-resolution electromagnetic tomography electrophysiological infraslow (<0.1 Hz) fluctuation neurofeedback (sLORETA eISF-NFB) 3 times per week over 4 weeks in participants (n=60) with IDs. Our primary aim will be to assess the clinical efficacy of sLORETA eISF-NFB via relevant patient-reported outcomes (PROs). Methods: We will randomly assign participants with a current diagnosis of MDD, GAD, and/or SOC to one of four groups: 1) 12 sessions of posterior cingulate cortex (PCC) up-training (n=15), 2) 6 sessions of yoked-sham training followed by 6 sessions of PCC up-training (n=15), 3) 12 sessions of concurrent mid-cingulate (MCC) down-training and PCC up-training (n=15), or 4) 6 sessions of yoked-sham training followed by 6 sessions of concurrent MCC down-training and PCC up-training. Transdiagnostic PROs, as well as resting-state neuro-physiological measures (EEG; electrocardiography, ECG; electrodermal activity, EDA), will be collected from all subjects at baseline, mid-training, 1 week post-training, and 1 month post-training. We will further compare baseline PROs and neuro-physiological measures to age- and sex-matched non-ID (i.e. no ID diagnosis) controls. Discussion: This protocol will outline the rationale and research methodology for a clinical trial of sLORETA eISF-NFB targeting key nodes within the core ICNs in a population with IDs with the primary aim being to assess its specific (e.g. non-placebo induced) efficacy via PROs. Trial Registration: Our study was prospectively registered with the Australia New Zealand Clinical Trials Registry (ANZCTR; Trial Id: ACTRN12619001428156)
Study on the Ecosystem Services of Urban Forests: Implications for Climate Change Mitigation in the Case of Adama City of Oromiya Regional State, Ethiopia
Authors: Koricho Hingabu Hordofa , Seboka Ararsa Derese , Fufa Fekadu , Gebreyesus Tikabo , Song Shaoxian 
Published: June 2021

Abstract
Background
this study was conducted to explore the ecosystem services of urban forests in Adama city, central Ethiopia. Attempts were made to quantify the carbon storage and sequestration, air pollution removal and hydrological benefits of urban trees. The urban forest structure and composition of the city was surveyed and analyzed. The i-Tree Eco Model was employed to analyze the ecosystem services based on the current urban forests structure of the city.
Results
the result revealed that the urban trees of the Adama city stored a total of 116,000 tons of carbon. The tree species identified with higher CO2 sequestration per year were Melia azedarach (15%), Eucalyptusglobulus (8%), Carica papaya (7%), and Delonix regia (6%). In addition, 22%, 12%, 10% and 4% of carbon were stored by Eucalyptus globulus, Melia azedarach, Carica papaya and Delonix regia tree species respectively. Moreover, trees and shrubs species in the city removed about 188 thousand tons of air pollutants caused by O3, CO, NO2, PM2.5 and SO2 per year. In Adama, 35% of the urban trees’ volatile organic compaound emissions were from Eucalyptus cinerea and Eucalyptus globulus. The monetary value of Adama urban forest in terms of carbon storage, carbon sequestration, and pollution removal was estimated to 43,781, 3,121 yr− 1 and 320,915,596 USD yr− 1, respectively.
Conclusions
it was concluded that significant quantity of CO2 and air pollutants were found being removed by the exotic tree and shrub species. However, every plant species found in the city does not mean ecologically important due their VOC emitting nature. Thus, the results of the study are valuable in increasing the awareness of the decision making bodies, the public and any stakeholders of the eco-benefits of urban trees in the mitigation of climate changes.
Evaluation of Dynamic Thiol-Disulfide Balance in Preinvasive Lesions of the Cervix
Authors: Sezgin Burak , Pirinççi Fatih , Camuzcuoğlu Aysun , Şahin Eda Adeviye , Erel Özcan , Neşelioğlu Salim , Camuzcuoğlu Hakan 
Published: June 2021

Abstract
Purpose: This study aimed to determine the potential clinical use of dynamic thiol disulfide balance in cases with preinvasive lesions of the cervix.Methods: One hundred and sixteen patients with high-grade squamous intraepithelial lesion, one hundred patients with low-grade squamous intraepithelial lesion and one hundred and ten healthy controls were enrolled in the study. A fully automated colorimetric system was used to determine the levels of thiol-disulfide parameters. The ischemia-modified albumin, total oxidant-antioxidant capacity, oxidative stress index of the retrieved cases were further analysed.Results: Native thiol and total thiol levels are significantly lower in the high-grade squamous intraepithelial lesion group according to control group (p:0.004 and p:0.015, respectively). Disulfide level is significantly increased in the high-grade squamous intraepithelial lesion group compared to control group (p:0.004). Oxidative stress index levels in high-grade squamous intraepithelial lesion group were observed as significantly higher according to the control group (p:0.014). Ischemia-modified albumin levels in the high-grade squamous intraepithelial lesion group were observed as significantly higher compared to the control group (p:0.020). Disulfide levels are positively correlated with risk type of Human papillomavirus (r:0.420, p<0.001).Conclusion: The analysis of dynamic thiol disulfide balance revealed considerable oxidative damage in patients with Human papillomavirus -related cervical precursor lesions compared to women with ordinary cytology specimens. Therefore, investigation of thiol disulfide balance with presented method represents a new promising test for early diagnosis and management of women at high risk for cervical cancer.