bluuebunny/crossref_metadata_2025 huggingface dataset:
Chitosan Hydrogels Crosslinked with Oxidized Sucrose for Antimicrobial Applications
Authors: Fujita Sayaka , Takeda Hijiri , Noda Junki , Wakamori Haruki , Kono Hiroyuki
Published: September 2023

Oxidized sucrose (OS) reacts with amino group-containing polysaccharides, including chitosan, without catalyst, resulting in hydrogels entirely composed of carbohydrates. The presence of imine bonds with low structural stabilities and unreacted aldehydes in the structures of these hydrogels hinder their application as biomaterials. Therefore, herein, the chitosan hydrogels (CTSGs) obtained after the crosslinking of chitosan with OS were reduced using sodium borohydride to convert imine bonds to secondary amines and aldehydes to alcohols. Structures of CTSGs were comprehensively characterized by Fourier transform infrared and 13C nuclear magnetic resonance spectroscopies, and results implied that the degree of crosslinking (CR) depended on the OS feed amount used during CTSG preparation. Properties of CTSGs were significantly dependent on CR; with an increase in CR, thermal stabilities and dynamic moduli of CTSGs increased, whereas their swelling properties decreased. CTSGs exhibited antimicrobial properties against the gram-negative bacterium Escherichia coli, and their performances were also dependent on CR. Results indicated the potentials of CTSGs completely based on carbohydrates as antimicrobial hydrogels for various medical and pharmaceutical applications. We believe that this study will contribute to the development of hydrogels for application in the food, medical, and pharmaceutical fields.
A Self-Attention Model for Next Location Prediction based on Semantic Mining
Authors: Lu Eric Hsueh-Chan , Lin You-Ru
Published: September 2023

With the rise of the Internet of Things (IOT), mobile devices and Location-Based Social Network (LBSN), an abundant amount of trajectory data has made research on location prediction more popular. The check-in data shared through LBSN hides information related to life patterns, obtaining this information is helpful for location prediction. However, the trajectory data recorded by mobile devices is different from check-in data that has semantic information. In order to obtain the user’s semantic, relevant studies match the stay point to the nearest Point of Interest (POI), but location error may lead to wrong semantic matching. Therefore, we propose A Self-Attention for Next Location Prediction based on Semantic Mining to predict the next location. When calculating the semantic feature of a stay point, the first step is to search for the k nearest POI, then use the reciprocal of the distance from the stay point to the k nearest POI and the number of categories as weights. Finally, we use the probability to express semantic without losing other important semantic information. Furthermore, this research combined with sequential pattern mining can bring richer semantic features. In order to better perceive the trajectory, temporal features learn periodicity of time series by sine function. In terms of location features, we build a directed weighted graph and regard the frequency of users visiting locations as the weight, so the location features are rich in contextual information. We then adopt the Self-Attention model to capture long-term dependencies in long trajectory sequences. Experiments in Geolife show that the semantic matching of this study improved by 45.78% in TOP@1 compared with the closest distance search for POI. Compared with the baseline, the model proposed in this study improved by 2.5% in TOP@1.
Sustainability of Urban Parks: Applicable Methodological Framework for a Simple Assessment
Authors: González Teresa , Berger Pia , Sánchez Claudia N. , Mahichi Faezeh
Published: September 2023

Urban parks play a pivotal role in fostering the development of sustainable and smart cities, encompassing multifaceted dimensions of environmental, social, and economic significance. To effectively manage these urban parks, it is imperative to undertake an in-depth investigation of their environmental, social, and economic conditions, as well as their level of sustainability. However, there is currently a lack of readily applicable methodologies that comprehensively measure these benefits and provide a sustainability rating for urban parks. In this study, we propose a valuable tool that employs effective and affordable measures for the daily management of these green spaces. Our methodology is rooted in the three pillars of sustainability: environmental, social, and economic. Within these pillars, we have defined 19 indicators and 50 criteria, enabling a comprehensive assessment of park sustainability. This methodology is developed through the characterization and systematic documentation of the park’s day-to-day operations. To validate our methodology, we present a case study of Cárcamos Park, situated in the state of Guanajuato in Mexico, utilizing accurate operational data collected from January to December 2020. Through this real-life scenario, we demonstrate the high applicability and effectiveness of our methodology. The sustainability assessment of Cárcamos Park reveals a sustainability level of 57%, placing it within the medium sustainability range. Importantly, our methodology can also be incorporated during the design phase of new urban green spaces, offering flexibility and ease of application tailored to the unique characteristics of each park. Park managers can use our procedure and apply it to any park, evaluate their sustainability status and detect areas of opportunity. Our approach provides a comprehensive and practical tool for measuring and improving the sustainability of urban parks. Its simplicity and applicability make it accessible to anyone interested in creating a greener and more sustainable urban environment.
Sustainable Solutions: Examining the Influence of Energy Subsidy Strategies on Urban Heat Islands in the Persian Gulf Region
Authors: Pour Maryam Nik , Chau Hing-Wah , Jamei Elmira
Published: September 2023

Ever since oil was discovered in the Persian Gulf Region in the 1920s, the oil and gas industries have been dominant in the area. These countries are responsible for generating approximately 35 percent of the world's natural gas and 25 percent of its crude oil, making them the largest crude oil producers globally. The release of carbon dioxide (CO2) into the atmosphere is directly linked to the use of fossil fuels. CO2 accounts for 58.8 percent of all greenhouse gas emissions caused by human activities and has a detrimental impact on urban residents through the urban heat island effect. A significant portion of these emissions can be attributed to residential buildings. Some nations exacerbate the problem by relying excessively on fossil fuels. Oil-rich countries provide energy subsidies to the public in order to lower energy costs for their citizens. However, this policy can have negative consequences, including wasteful energy usage in countries like Iran.
Teaching biodiversity: Towards a sustainable and engaged education
Authors: Id babou Asma , Selmaoui Sabah , ALAMI Anouar , Benjelloun Nadia , Zaki Moncef
Published: September 2023

The preservation of biodiversity has become a major concern in contemporary society. It is essential to understand teachers' representations of biodiversity to effectively guide educational efforts because of the significant role of education in raising awareness and promoting sustainable behavior. Through a survey of a sample of 118 teachers, we adopted a mixed-method approach combining both a closed questionnaire and interviews. We used these methods to explore teachers' representations of the concept of biodiversity as an integral part of the school curriculum, as well as to gather their views on certain features of its teaching. The results state that the majority of teachers perceive biodiversity as a whole and in its most complex relationships. During their professional experience, they have developed a biocentric and anthropocentric conception of biodiversity. This study provides valuable information to guide future pedagogical practices and educational policies in sustainable education.
The Impact of Reading Modalities and Text Types on Reading in School-Age Children: An Eye-tracking Study
Authors: Kim Wi-Jiwoon , Yoon Seo Rin , Nam Seohyun , Lee Yunjin , Yim Dongsun
Published: September 2023

This study examined the eye movement patterns of 317 elementary students across reading conditions (audio-assisted reading (AR) and reading-only (R)) and text types (fiction and non-fiction), and identified eye movement parameters that predict their literal comprehension (LC) and inferential comprehension (IC). Participants, randomly assigned to either reading condition and either text type, answered questions assessing their LC and IC. Average fixation duration (AFD), total fixation duration (TFD), and scanpath length were used as eye movement parameters. There were main effects of age on all parameters and interaction effects between age and reading condition on TFD and scanpath length. Controlling for age, TFD had a positive impact on LC of both text types in the AR, while under the R, it affected negatively on IC of both text types. Longer scanpaths predicted IC of fiction in the AR, LC and IC of non-fiction under the AR, and LC of non-fiction within the R. AFD influenced negatively on IC of fiction in the AR, LC and IC of non-fiction in the AR, and LC of non-fiction under the R. These eye movement patterns and predictors indicate children employ different reading strategies based on reading modality and text type.
Exploration and Enhancement of Classifiers in the Detection of Lung Cancer from Histopathological Images
Authors: Shanmugam Karthikeyan , Rajaguru Harikumar
Published: September 2023

Lung cancer is a prevalent malignancy that impacts individuals of all genders and is often diagnosed late due to delayed symptoms. To catch it early, researchers are developing algorithms to study lung cancer images. One such method uses computer aided detection to classify as benign or malignant from the histopathological images. Standard histopathological images were used from a Lung and Colon Cancer Histopathological Image Dataset (LC25000) which contains two classes of benign and malignant of 5000 each. Images were preprocessed and features extracted using Particle Swarm Optimization (PSO) and Grey Wolf Optimization (GWO). Feature selection methods used are KL Divergence and Invasive Weed Optimization (IWO). Seven different classifiers like SVM, KNN, Random Forest, Decision Tree, Softmax Discriminant, Multilayer Perceptron, and BLDC were used to analyze and classify the images as benign or malignant. Results were compared using standard metrics, and kappa analysis assessed classifier agreement. The Decision Tree Classifier with GWO feature extraction achieved good accuracy of 85.01% without Feature selection and Hyperparameter Tuning approaches. Furthermore, we present a methodology to enhance the accuracy of the classifiers by employing hyperparameter tuning algorithms based on Adam and RAdam. By combining features from GWO and IWO, and using the RAdam algorithm, the Decision Tree classifier achieves the commendable accuracy of 91.57%
Medical Application of Molecular Hydrogen to Diabetic Kidney Disease: Therapeutic Potential through Improvements in Mitochondrial Function
Authors: Hirano Shin-ichi , Ichikawa Yusuke , Sato Bunpei , Takefuji Yoshiyasu , Satoh Fumitake
Published: September 2023

With the rapid increase in diabetes worldwide, the number of patients with diabetic kidney disease (DKD), a complication of diabetes mellitus, is also on the rise. DKD is a major cause of chronic kidney disease progressing to end-stage renal failure; however, current medical treatments for DKD do not achieve satisfactory outcomes. Molecular hydrogen (H2) is an antioxidant that selectively reduces hydroxyl radicals, a reactive oxygen species with a very potent oxidative capacity. H2 was recently shown to exert not only antioxidant, but also anti-inflammatory, cell lethality-regulating, and signal transduction-regulating effects, and is now being applied clinically. Many factors contribute to the onset and progression of DKD, with mitochondrial dysfunction, oxidative stress, and inflammation being strongly implicated. Recent preclinical and clinical trials reported that substances with antioxidant properties may slow the progression of DKD. Therefore, we conducted a literature review on animal models and human clinical trials in which H2 showed efficacy against various renal diseases. This literature review and our previous findings collectively suggest that H2 exerts therapeutic effects in patients with DKD by improving mitochondrial function. Future large-scale clinical studies are needed to confirm these findings.
Artificial Intelligence and Its Impact on the Moroccan Labor Market: Job Disruption or Transformation?
Authors: Tachicart Ridouane
Published: September 2023

Artificial Intelligence (AI) stands as an emerging technology poised to reshape various facets of our daily lives, with a particularly noteworthy influence on the labor market. In Morocco, AI adoption has commenced in diverse sectors, including finance, insurance, and telecommunications, opening up fresh avenues for employment. Nevertheless, this technological shift also ushers in challenges for Moroccan workers, necessitating training and upskilling to effectively engage with AI-driven systems. Within this article, we delve into the burgeoning impact of AI on the Moroccan economy and job landscape, delving into both the opportunities and obstacles that accompany its proliferation. Furthermore, we explore strategies that authorities and businesses can employ to harness the benefits of AI while mitigating its potential adverse effects on Morocco's workforce.
The Importance of Resistance in the Context of Critical Infrastructure Resilience: An Extension of the CIERA Method
Authors: Rehak David , Flynnova Lucie , Hromada Martin , Fuggini Clemente
Published: September 2023

Technical sectors are an inseparable and elementary part of a critical infrastructure (CI) complex system. The services they provide are essential to the functioning of all the dependent sectors of CI on whose services society depends, especially in areas with high levels of urbanisation. The starting point for effective CI elements protection of is permanent assessing and strengthening their resilience to the negative effects of internal and external threats. Current perceptions of resilience focus primarily on repressive components responsive to incident (i.e., robustness, recoverability, and adaptability), while little attention is paid to preventative components. Therefore, the benefit of the article is to define resistance which could be seen as the CI element ability or characteristic to prevent the occurrence of incidents. Based on that, the article defines 1) the individual factors (variables and parameters) determining the CI resistance and 2) the methodological procedure for infrastructure elements resistance assessment in order to identify weak points and subsequently strengthen them. The essence of the article is defining the starting points for extending the CIERA method by a component strengthening the critical infrastructure resilience in the prevention phase. A practical example of resistance assessment for a selected critical energy infrastructure element is presented at the end of the article.
Investigation of Risk Factors Affecting Vitamin B12 Deficiency in Children
Authors: Elgormus Yusuf , Okuyan Omer , Dumur Seyma , Sayili Ugurcan , Uzun Hafize
Published: September 2023

Background: Vitamin B12 is a water-soluble vitamin with important cellular functions and is an essential vitamin. The aim of this study is to determine the B12 levels of children in the period from the 6th month when they start taking additional foods to the age of 7 and the risk factors affecting them. Methods: One hundred pediatric patients aged 6-72 months who were diagnosed with vitamin B12 deficiency and their parents who agreed to participate in Istanbul Atlas University, Medical Faculty, “Medicine Hospital” Pediatric Clinic between September 2022 and June 2023 were prospectively included in this study. Results: B12 deficiency was significantly higher in the 6-11 (25%) month group than those in the 12-23 (5.8%) and 24-47 (2.8%) month groups. Homocysteine levels were highest in those with insufficient B12 levels compared to the other groups. There was no statistically significant difference in weekly dairy and meat consumption levels between age groups. B12 levels were lower in the 6-11-month group than in the other groups. Homocysteine levels were highest in those with insufficient B12 levels [<200 pg/mL (148 pmol/L)]. Folic acid levels were lower in the 24-47 month and 48-72 month groups than in the 6-11 month and 12-23 month groups. Conclusions: The results obtained in this study showed that low vitamin B12 and increased homocysteine levels seem to be important risk factors in children, especially from the 6th month when they start taking additional foods. The diagnosis of B12 deficiency can be confirmed by elevated serum total homocysteine levels, which are evidence of functional cobalamin deficiency.
The Use of β-Blockers and the Risk of Undergoing a Knee Arthroplasty
Authors: Tamimi Iskandar , García-Meléndez Gaspar , Vieitez-Riestra Ignacio , Palacios-Penedo Sergio , Garceso Diego Moriel , Sanchez Alejandro , Tamimi Faleh , Guerado Enrique , Milner Marc Stefan Dawid , de Quevedo David Garcia , Gonzalez-Quevedo David
Published: September 2023

Background:

Research has indicated that β-blockers may downregulate various inflammatory mediators that are involved in osteoarthritis (OA). The objective of this study was to analyze the likelihood of total knee arthroplasty (TKA) among patients with OA who were being treated with β-blockers.

Methods:

A nested case-control study was conducted with use of clinical records from our institutional database. We included patients who attended our outpatient clinic with a history of new-onset knee pain between 2010 and 2019. The case group included individuals who had undergone primary TKA between 2018 and 2019, whereas the control group included subjects who had not undergone TKA. Controls were matched by date of birth ±2 years, sex, calendar time (first outpatient visit ±1 year), and the grade of arthritis; the control-to-case ratio was 1:1. Adherence to β-blocker use was measured with use of the proportion of days covered (PDC) (i.e.,<0.25, ≥0.25 to <0.75, ≥0.75), and the cumulative effect was measured on the basis of the total number of years of treatment with β-blockers. A binary logistic regression analysis adjusted to potential confounders was carried out to assess the risk of TKA associated with the intake of β-blockers.

Results:

A total of 600 patients were included (300 in the case group and 300 in the control group). Compared with non-users, any use of β-blockers during the follow-up period was associated with a reduction in the likelihood of undergoing TKA (adjusted odds ratio [OR], 0.51; 95% confidence interval [CI], 0.34-0.77). The adjusted ORs for the use of selective β1-blockers and nonselective β1-blockers were 0.69 (95% CI, 0.36 to 1.31) and 0.42 (95% CI, 0.24 to 0.70), respectively. The adjusted ORs for any recent use, PDC of <0.25, PDC of ≥0.25 to <0.75, and PDC of ≥0.75 were 0.65 (95% CI, 0.51 to 0.99), 0.62 (95% CI, 0.21 to 1.85), 0.32 (95% CI, 0.09 to 1.22), and 0.55 (95% CI, 0.34 to 0.88), respectively. Regarding the cumulative effect of β-blockers, the adjusted ORs for the use for <1 year, ≥1 to <5 years, and ≥5 years were 0.41 (95% CI, 0.20 to 0.85), 0.52 (95% CI, 0.21 to 1.33), and 0.36 (95% CI, 0.22 to 0.60), respectively.

Conclusions:

The use of nonselective β-blockers was associated with a lower likelihood of undergoing TKA. Patients treated for prolonged periods were at a lower likelihood for undergoing TKA.

Level of Evidence:

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
Clinical and Echocardiographic Profile of Patients with Chronic Obstructive Pulmonary Disease
Authors:   Assistant professor, Department of Medicine, B.J. Medical College, Civil Hospital Campus, Asarwa, Ahmedabad, Gujarat 380016, India., Gupta Nidhi , Vora Chitralekha ,   Associate professor, Department of Medicine, B.J. Medical College, Civil Hospital Campus, Asarwa, Ahmedabad, Gujarat 380016, India., Garg Pankaj ,   Associate Professor, Department of CVTS, B.J. Medical College & U.N. Mehta Institute of Cardiology and Research Center, Civil Hospital Campus, Asarwa, Ahmedabad, Gujarat 380016, India., Patel Kinjal ,   Junior Resident, Department of Medicine, B.J. Medical College, Civil Hospital Campus, Asarwa, Ahmedabad, Gujarat 380016, India., Chovatiya Harshad ,   Junior Resident, Department of Medicine, B.J. Medical College, Civil Hospital Campus, Asarwa, Ahmedabad, Gujarat 380016, India.
Published: September 2023

Background: Chronic obstructive pulmonary disease is the fourth leading cause of mortality worldwide. It is defined as a disease formal categorized by airflow limitation that is not fully reversible. Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of cardiovascular disease. Electrocardiography (ECG) carries information about cardiac disease and prognosis in COPD patients. However, Echocardiography provides a rapid, noninvasive, portable, and accurate method to evaluate cardiac functions. Methods: 125 patients of COPD fulfilling the inclusion criteria coming to OPD/ wards of Medicine, Civil Hospital, Ahmedabad were recruited. They were staged by pulmonary function test (PFT) and evaluated by electrocardiography and echocardiography. Statistical analysis of correlation was done with chi square test and statistical significance was taken p<0.05. Results: Mean age was 56.24±9.41years, with male preponderance, male to female ratio 4.43:1. Mean duration of disease was 6.22±4.28years. The common symptoms were Breathlessness (100%). Most common ECG and ECHO finding was RAD (51.2%) and PAH (54.4%) respectively. Statistically Right axis deviation and Poor ‘r’ wave progression were significantly correlated with disease severity by ECG findings while R.A. dilatation, R.V.dilatation and Pulmonary hypertensionwere significantly correlated with disease severity by ECHO findings (p<0.05). Conclusions: COPD is more common in males and in the 5th and 6th decadeof life. Most of the patients have fairly advanced disease at presentation. The incidence of abnormalities of ECG and echocardiography increases with COPD severity. ECG and echocardiography are better tools than clinical methods in detecting R.V. dysfunction in COPD.
Improving EOR Economics by Polymer Technology Development
Authors: Toivonen S. , Johnson G. , Hanski S. , Lynch T. , Rosati L. , Pin E. , Lugo N.
Published: September 2023

Recent advancements in polymer technology have played an important role in enabling polymer flood projects and widening the spectrum of applicable conditions for use. These improvements have generated clear benefits to operators by improving the economic and environmental measures for these projects.

In the Captain field, located in the UKCS of the North Sea, a liquid, high active, +50% anionic polyacrylamide polymer has been injected since 2017 within the Captain Stage 1 polymerflood development. This large scale offshore polymerflood project has proven the benefit of polymer EOR technology in an offshore setting, with clear production responses across all polymer injection patterns. This paper describes the impact of polymer product development on the overall efficacy of the polymer project at Captain, including savings related to polymer consumption. This progress has a direct effect on overall logistic and supply chain improvements, offshore inventory needs, and results in a reduction of CO2 emissions related to polymer production and transportation.
A New Method for Quantitative Diagenesis via Digital Rock Tools
Authors: Japperi N. S. , Wu K. , Starkey A. , Panaitescu C.
Published: September 2023

The quantitative study of cementation plays a critical role in characterizing sedimentary rocks, with significant implications for geology, petroleum engineering, and environmental science. By understanding the evolution processes of cementation, researchers can enhance the interpretation of diagenesis in reservoir rocks and accurately quantify the properties influencing the displacement of hydrocarbons. Accurate quantification of reservoir rock properties is essential for developing reservoir models, particularly for heterogeneous rocks. Furthermore, understanding the pore system that controls hydrocarbon or CO2 flow in reservoir rocks is crucial for predicting hydrocarbon displacement and CO2 storage efficiency. Therefore, a quantitative method is required to gain a comprehensive understanding of the diagenesis of reservoir rocks and their pore structure.

This study aims to use the detailed pore structure and diagenesis information from high-resolution scanning electron microscopy (SEM) imaging to quantify the diagenesis linked to the reservoir rocks’ quality. The methodology involves categorizing rock samples into three different classes based on the quantification of pore and grain size distribution and cement spatial distribution features. The North Sea Oil Field data is used as a case study.

Here, it also presents a quantitative approach for classifying pore, grain, and cement features using gray-value threshold segmentation. The method consists of two steps. First, the quantitative cement features are classified. Then, we link the diagenesis process with these quantitative cement features, enabling the evaluation of diagenesis in sedimentary rocks and its impact on hydrocarbon displacement and CO2 storage efficiency. The results of this characterization method demonstrate its effectiveness in distinguishing and quantifying pore, grain, and cement distributions. Moreover, it establishes a connection with lithofacies and well logging features.

In summary, our study highlights the importance of quantifying cementation in sedimentary rocks for various engineering and scientific disciplines. By utilizing high-resolution SEM imaging and employing the gray-value threshold segmentation method, we successfully classify and quantify pore, grain, and cement features. The findings have significant implications for the development of accurate reservoir models and improved resource management.
Slickline Deployed Fibre Optic Cable Provides First Ever Production Profile For High Temperature Gas Well
Authors: Berry S. , Dirya D. , Cowie G. , Hooker A. R. , Innes R. , Gray R.
Published: September 2023

Distributed Fiber Optic Sensing (DFOS) allowed us to continuously gather flow profile information from a high-temperature high-rate gas well. The objective of this case study is to demonstrate that Distributed Temperature and Distributed Acoustic data, thermal inversion modelling can be used to produce a Production Flow Profile in an environment where conventional production logging was not possible.

Cerberus modelling was performed, concluding there was a risk of tool lift whereby a conventional production logging tool string is deployed during flowing states. Therefore, a 0.181" diameter fiber slickline was selected to allow a continuous measurement over the accessible perforation interval at multiple rates without the risk of tool lift. A program consisting of a memory production log, run by standard slickline cable to acquire a shut-in profile looking for potential crossflow was followed by a DFOS run to gather DAS and DTS data during shut-in and flowing rates of 30 MMSCF/Day and 60MMSCF/Day. Near real-time DTS data was analyzed to aid in the evaluation of temperature stability at each rate change, and DAS data was processed at the wellsite to enable transmission to and analysis onshore.

DFOS data was successfully acquired and processed at wellsite and transmitted to town allowing for monitoring of data quality and decision making during the intervention. A complete suite of DAS/DTS data was acquired over the perforated interval at multiple flow rates, facilitated by monitoring near real-time transient behavior which aided in decision making for rate changes. Thermal inversion modelling and DAS analysis were performed, providing evidence of crossflow during shut-in and variations of flow allocation during the differing flow rates. It was observed that surveying at lower flow rates would have provided a different flow profile compared with normal operating rates.

As a result of deploying DFOS, data could be acquired at more realistic rates. Through performing thermal inversion of the DTS data and analysis of the DAS data a more accurate flow profile was achieved. This is the first profile to be acquired in the field for use in reservoir simulation and production modelling. This will result in more accurate reservoir and well optimization. This is a layered sandstone reservoir with a two-thirds production drop since start-up in this well. Approximately 80% of production was produced from one zone and surveillance to plan remedial action was essential to maintain economic production.
Integrating North Sea Sectors for the Development of Commercially Viable Renewable and Low Carbon Hydrogen
Authors: Haase A.
Published: September 2023

This paper assesses the opportunity for an integrated and circular approach to developing our offshore energy sector as we embark on the energy transition. It evaluates how offshore wind, green hydrogen production and heritage oil and gas expertise can be synthesised together to benefit all sectors to support a viable green hydrogen and wind economy.

The renewable hydrogen sector has struggled to establish a sustainable commercial model so far. This paper finds there may be significant advantages to be found in taking hydrogen production offshore, solving commercial challenges for both hydrogen and offshore wind developers, while also repurposing oil and gas expertise and assets to feed the energy transition and accelerate production timelines.

Offshore engineering experience, research, and live case-studies are utilised to investigate the opportunities for this approach. It also considers the commercial viability and benefits, as well as the ultimate offtake and transportation for produced green hydrogen and electricity.
Geomechanical Analysis of Caprock Integrity and Fault Stability for Greensand CO2 Storage Project Feasibility
Authors: Younessi A. , Kårstad E. , Basu P. , Larsen M. , Burachok O.
Published: September 2023

A comprehensive geomechanical assessment is carried out to investigate the upper pressure limit of CO2 injection for the depleted oil Frigg Sand reservoir in Nini field, offshore Denmark. The mechanical stability of the Frigg Sand reservoir, shale caprock and key intersecting faults were investigated under the forecasted CO2 injection plan using a field-scale coupled finite element model built for the target storage reservoir. The field-scale geomechanical model is built by preparing a 3D grid which covers the entire Greensand field structure including the basement and overburden up to the seabed. The geomechanical properties and parameters are constrained using the well-centric data and propagated in 3D grid using geostatistical approach combined with surface seismic data. A finite element model is prepared and coupled with the reservoir flow dynamic model for the interested zone of the studied area. The results of the finite element model are used to investigate the integrity of the caprock and stability of the faults over the life of the field. The results of the finite element simulation shows that the calculated minimum principal stress does not change its state to tension in any part of the field. However, a reservoir pressure above the minimum principal stress magnitude in base of the caprock may increases the risk of failure in the caprock. Hence, considering the uncertainty for the lower bound of the minimum principal stress, the risk of failure in the caprock is low until the Frigg Sand reservoir pressure exceed the estimated threshold pressure. The results also show that there is no risk of shear failure in the caprock for the entire studied area. The fault stability analysis shows that no risk of fault reactivation exists in the overburden. However, some faults may reach the critical stress state in the reservoir with high injection pressures. A reactivation in the reservoir layer may extend to the overburden and increase the risk of caprock integrity failure. Overall, the most critical mode of failure is the possible tensile failure which defines the safe operational limit for the Frigg Sand reservoir. The thorough analysis using field scale finite element simulation coupled to the reservoir flow dynamic helped to capture the risk associated to the CO2 injection operation and optimize the injection plan.
Hydrogen Backbone Link Project - Connecting Scotland to the European Hydrogen Backbone
Authors: Milne C.
Published: September 2023

The production and use of low carbon hydrogen will play a key role in helping Europe deliver its climate objectives and reach net zero. Affordable hydrogen transport is fundamental, with an expected opportunity for the oil and gas sector to support the development of the hydrogen economy by repurposing existing infrastructure. However, hydrogen differences from natural gas or the availability of existing infrastructure is a complex changeover to be readily available by the 2030s.

Part-funded by the Scottish Government via the Energy Transition Fund, with matched funding from industry partners during Phase 1 including Kellas Midstream, Shetland Island Council, EnQuest, Shell and Crown Estates Scotland, the Hydrogen Backbone Link (HBL) project aims to connect Scotland to the European Hydrogen Backbone to create export opportunities for Green H2 and H2 technologies. This will support the development of pan-European hydrogen infrastructure and create export capabilities by repurposing and optimising existing pipelines, installing new pipelines, or utilising other options such as marine transport by ship.

A pipeline can only be studied while considering the associated infrastructures; hence the scope was broken down to 12 separate studies including blending & deblending, hydrogen storage, compression, metering and valves. Business case risk assurance and economic modelling were also developed.

Phase 1, a feasibility stage of the project, is complete and includes 12 reports which provide the following:

Options for export methods. Options for existing or new pipelines. Findings and next steps for associated infrastructure and systems.

The studies proposed that a new pipeline is required directly from Shetland Voe Terminal or Flotta to Europe, using Emden in Germany as a study case. The new pipelines offer many advantages including operational independence, and a competitive business model of 6 % IRR with a tariff of £0.32/kg (Wood Mackenzie 2022).

With recommendations provided from Phase 1, Phase 2 is now ready to start and will include further engineering, physical testing and lab work, such as large-scale hydrogen specific metering tests. The Hydrogen Backbone Link Project continues with the goal of connecting Scotland to Europe by 2030s, within the overall target of achieving net zero.
Estimating Dynamical Mineral Dissolution for Co2 Injection Into Saline Aquifers Utilizing Deep Learning in the Ahuroa Saline Aquifer
Authors: Katterbauer Klemens , Al Shehri Abdallah , Qasim Abdulaziz , Yousef Ali
Published: September 2023

The geological carbon storage (GCS) in subsurface environments, such as deep permeable saline formations, is one of the achievable methods for carbon dioxide storage. There are several commercial projects such as the Sleipner field in Norway, and in Salah in Algeria have demonstrated that carbon dioxide can be safely stored in these reservoirs. The natural environments are capable to store CO2 on geologic time scales, that is mostly caused by solubility trapping. While the geological, physical and chemical conditions for the escape of CO2 are still in the research phase and how CO2 can be efficiently stored, there are several important features that represent prerequisites for the efficient storage (Xu, et al. 2017).

A core prerequisite is the availability of sufficient porosity in order to accommodate the desired volumes of carbon dioxide, and the presence of a continuous cap rock that is impermeable to CO2. Deep saline reservoirs are attractive candidates for the geological storage and based on the deep geologic storage temperature and pressure, the CO2 is typically in a supercritical but stable state. The challenge is that the introduction of CO2 into the reservoir may lead to a geochemical process which acidifies the brine via CO2 dissolution. Furthermore, the mineral surfaces are dehydrated by the dispersing CO2 phase. Experimental and field studies indicate that the geochemical reactions caused by the injection of CO2 may vary significantly between different rock types and brine compositions (Michael, et al. 2010). The low permeability of the cap rock, such as shale, have demonstrated to be reactive for higher temperature ranges, which poses additional challenges for the CO2 storage process. The dissolution and re-precipitation of carbonate minerals, and the dissolution of feldspars are generally observed for these CO2 storage reservoir sites that additionally encounter challenges related to the precipitation of clay minerals. This implies that the dissolution and secondary mineral precipitation caused by the injection of CO2 have a major impact on the porosity and permeability of the reservoir environment as well as impact the cap rock integrity (Jiang, et al. 2014).
Drilling Solutions for Offshore Wind Foundations and Export Cable Landfalls
Authors: Peters M.
Published: September 2023

The development of renewable energies is the focus for future energy supply. Large offshore wind farms are to be constructed and connected to a high-capacity trans-mission grid. Due to the public environmental awareness, smart installation methods are required for fast and safe construction of offshore foundations and the eco-friendly landfall installation for the export cables, with minimal impact on surroundings.

The installation of offshore foundations requires drilled installation methods, espe-cially in non-drivable soil conditions and medium to higher water depths. In addition to limitations in certain ground conditions, conventional pile-driving is reaching its limits with increasing turbine sizes. Furthermore, pile-driving has a deep environ-mental impact. Noise emissions can either require complex and expensive noise mitigation systems or cause lasting damage to flora and fauna. In the past, offshore drilling rigs have only been a non- performance driven backup option for pile-driving installations. Today, the Offshore Foundation Drilling technology provides a com- pletely drilled installation of offshore foundations, e.g. for monopile structures, pin-piles or floating anchor piles. High drilling performances can be achieved, that were previously only known in the horizontal drilling industry. Lower forces on the foun-dation pile during installation allow a more economical static pile design. Acoustic emissions can be largely avoided which finally can also lead to longer and more flexible time frames for construction. In 2022, the first equipment worldwide has been used as a standard installation method for XXL monopiles for the St. Nazaire wind farm in France, installing a total of 73 monopiles by drilling and grouting with a drilling diameter of 7,700 mm, in wa-ter depths of 15 to 25 m in rocky seabed.

The landfall sections of export cables coming from offshore wind farms are usually located in sensitive coastal areas where the operation of heavy construction equip-ment is not possible due to environmental protection requirements. Also, when dyke structures have to be crossed, this sets further increased demands on the safety as-pects of respective trenchless installation methods. Even if HDD presents a common technology for the installation of casings for subsequent pull-in of the export cables, the alternatives with remote- controlled microtunnelling systems such as Pipe Jacking or Direct Pipe need to be carefully investigated. In any case, the drilling works can be carried out from onshore to offshore to reduce marine construction costs, whereas the protective pipe can be inserted from the seaward side in a second step. This paper will give an overview of the drilled approach for offshore founda-tions and the application range of trenchless methods for export cable landfalls.
Deep Insight into Electrical Submersible Pump Maintenance: A Predictive Approach with Deep Learning
Authors: Abdalla Ramez , Nikolaev Denis , Gönzi David , Manasipov Roman , Schweiger Andreas , Stundner Michael
Published: September 2023

Artificial lift systems play a crucial role in the oil and gas industry by maintaining or enhancing production rates through the conversion of kinetic energy into hydraulic pressure. However, identifying abnormal performance and preventing failures remains a major challenge. Failures occur when key parameters deviate from safe operating conditions, leading to downtime and loss of production volumes. To address this challenge, the objective is to establish repeatable frameworks for constructing predictive models through the utilization of deep learning algorithms. These models provide support for engineering and operational teams through a connected alarm system that sends prescriptive notifications, enabling prompt and informed decision-making.

We approach the problem of predictive maintenance for electrical submersible pumps using a multi-task classification method. The different types of faults that can occur in these pumps are treated as individual tasks, and each task is represented by different severity grades to be predicted. To handle this multi-task classification problem, a unique model is trained end-to-end by defining a multi-task loss function. We have evaluated two different architectures for feature extraction, including a 1D CNN and an LSTM with an attention mechanism. The 1D CNN architecture consists of two convolutional and max pool layers, along with batch normalization to facilitate training. The LSTM architecture with attention was found to perform better than the vanilla LSTM in this multi-task classification problem.

This study evaluated two architectures for their performance in the predictive maintenance of electrical submersible pumps: 1D CNN and LSTM with an attention mechanism. The results showed that the LSTM with attention using lookback architecture exhibited the best performance and was the easiest to train. The 1D CNN had a comparable performance but exhibited some overfitting in the current configuration. These findings highlight the potential of using 1D CNNs for this application and the importance of attention mechanisms in LSTM models.

The maintenance of Artificial Lift Systems (ALs) requires significant resources and is traditionally performed through reactive process monitoring. An automated predictive maintenance solution using deep learning has been developed, including predictive models and a best practices guideline. This work introduces a novel automated system to reduce failures by analyzing real-time sensor data and statistical parameters to predict failures in ALs. The predictive tool supports work over plans including ESP replacement strategies, and reduces production losses.
Application of an Improved Deep-Learning Framework for Large-Scale Subsurface Flow Problems with Varying Well Controls
Authors: Huang Hu , Gong Bin , Sun Wenyue , Qin Feng , Tang Shenglai , Li Hui
Published: September 2023

The embed-to-control (E2C) framework provides a new deep-learning-based reduced-order modeling framework for much faster subsurface flow predictions than traditional simulation. However, the previous E2C model entails a large number of model parameters, which limits its applicability to large-scale cases. In addition, the previous E2C model has not been applied to a gas-driven subsurface system or well-control optimization. In this work, we make several improvements to the previous E2C framework for more complex and larger-scale problems. First, we reduce the output dimension of the middle layers by increasing the number of downsampling layers and using the depth-wise separable (DWS) convolution techniques in the deconvolution operation. Second, we use the global average pooling (GAP) technique to reduce the model parameters. Third, we apply an “add” operation in the skip connection to fuse the features. The improved E2C surrogate model is applied to a high-dimensional gas system with flow driven by six wells operating under time-varying control specifications. In this case, we can reduce the graphics processing unit (GPU) memory usage from 19.22 GB to 2.57 GB. In the training process, a total of 160 high-fidelity simulations are performed offline, out of which 130 simulation results with partial time sequence are used for training the E2C surrogate model, which takes about 46 hours on an RTX 3090 GPU. The trained model is shown to provide accurate production forecasts under various well control scenarios during the prediction period. The online computations from our E2C model are about 6.5 seconds per case, which achieves a speedup of more than 500 factors to corresponding full-order simulations, which take about 1 hour per run. Finally, the improved E2C model, in conjunction with a particle swarm optimization (PSO) technique, is applied to optimize the injection well strategies of an oil-gas-water field case with 189 wells (i.e., 96 producers and 93 injectors). Due to the significant speedup and high accuracy of the improved surrogate model, it is shown that improved well-control strategies can be efficiently obtained.
Tribological characteristics of three-body abrasive wear on MoS2 films
Authors: CHENG Weilun , DONG Shaojiang , ZOU Song , HU Bo , LIU Qingyi
Published: September 2023

Aiming at the problem of the failure of bearing lubrication caused by the entry of fine dust into the spacecraft, a molecular dynamic simulation method was proposed to study the wear characteristics of the bearing lubricating film. Firstly, the atomic model of MoS2 thin film is established, and the motion state of dust particles on the surface of MoS2 thin film is divided (sliding abrasive and rotating abrasive). Secondly, the characteristics of sliding and rotating abrasive wear are studied by applying different loads to the abrasives. Finally, the surface structure of the substrate was changed to explore the adsorption and wear characteristics of the one-dimensional rough substrate. The following conclusions are obtained: 1) sliding abrasive and rotating abrasive have different wear mechanisms. The wear of sliding abrasive originates from the accumulation and release of tangential force. The main source of wear in rotating abrasive is the release of tangential force and the action of tangential force caused by rolling; 2) The relationship between sliding friction and rolling friction at the atomic scale is the same as that at the macroscopic scale. Rolling friction is much less friction than sliding friction. Rolling friction causes less damage to the film than sliding friction; 3) The one-dimensional rough substrate reduces the contact area between the film and the film, resulting in a decrease in the adsorption between the film and the substrate. The asperity structure of rough substrates reduces the lubricity of the film compared to smooth substrates.