bluuebunny/crossref_metadata_2025 huggingface dataset:
Challenges of Gas Wells Killing Operation with Emphasis on Reservoir & Completion Integrity Issues
Authors: Ahmad Zeeshan , Al Hosini Abdullah Alhaj , Al Janahi Mohammed Ibrahim , Al Marzouqi Abdulla Mohammed , SIDDIQUI Muhammad Ali , Al Zarouni Abdulla Haidar Abdulla , Ansari Saad Wajih Uddin
Published: December 2021

Well killing always remains a most radical part during the life cycle of gas production wells with reservoir and completion integrity issues. In moderate permeability gas reservoirs, it will be more challenging due to below issues;

Low pressure gas reservoir with moderate reservoir permeability where hydrostatic head of water is almost double the formation pressure

Well with the sustainable annulus pressures (Production & first cemented annulus) Well with complex layered scale / asphalting deposition Completion jewelry component integrity breached Recycle reservoir with pressure maintenance

Noise logs / corrosion logs generally conducted in order to assess the downhole completion jewelry and potential leak source prior any attempt for killing the well. To achieve the desired accessibility extensive scale analysis for better designing of scale clean out operation carried out specially to access the SPM. Variation of reservoir permeability considered for designing of optimized kill fluid for Depleted horizontal gas reservoir to cater challenge of complete losses. Effective fluid loss solutions designed and implemented to avoid abnormal fluid losses. Further more Polymer based gels used to kill and prevent the gas peculation to surface.

Wells having completion and reservoir integrity issue isolated by considering cement zonal isolation, salt plugs, thru-tubing bridge plugs and nipple less plugs. All these barriers having their advantages and disadvantages with reference to work over objectives and their application limitations with respect to well conditions and detail study conducted for each candidate prior execution.

Depletion Gas well killing and securing operation considered to be complex in nature and may result serious concern of rig intervention or well future objectives in case of improper execution. Gas wells having reservoir integrity issues and in case of 1st cemented Annulus pressure can be isolated by using thru-tubing bridge plugs. For retrieval of dummy from SPM must be done after setting of downhole plug to avoid any heavy suction for wire line operation. Cement plug operation is not suitable for such wells due to severe losses and fluid circulation limitation. Adequate selection of kill gel fluid as per reservoir characteristics will improve the killing efficiency.
A Case Study on Project Realization Digitalization from the Domain Perspective
Authors: Mohd Azmi Nurul Aminah , Veroba Grant , Zainalabidin Muhammad Aizuddin
Published: December 2021

This paper provides a Case Study in Front End Project Realization digitalization from the Domain perspective, with a focus on the methodology used, process enhancements that were enabled through automation, and lessons learned during the transformation.

The transformation has been an iterative process, first focusing on digitalizing modules within the Front End work process and evolving into a multi-discipline integrated digital application. Along the journey, application of Agile project strategies enabled continuous enhancements to be identified and implemented through lessons learned, formal design thinking reviews, new idea generation and informal engagements with other disciplines commencing their digital journey. The process enhancements include: New Ways of Working to seamlessly integrate Front End technical and cost analytics engines, and across broader enterprise digital Field Development processes.New Sources of Insight to expand ideation using cross industry learnings, maximize use of extensive internal project data, and embedded Best in Class benchmarking.

The Front End digitalization process identified significant value to stakeholders through increased pace of delivery, improved early concept definition with limited human intervention, increased cost accuracy, and increased confidence in the results through replication, improved data supply and benchmarking rigor. Specific value unlocks are seen across Front End Loading (FEL) i.e., pre-FEL to FEL-2 stages and will be presented. Through incorporation of enhanced data and insights, improved cost compression and decision-making quality has also been identified and subsequently will improve the project economics.

A number of challenges through the transformation process were identified. These included: integration or replacement of legacy technical and cost applications; identifying and digitalizing a wide range of internal engineering tools and data sources needed for a comprehensive digital Front End process; efficiency of translating technical requirements to the digital team through comprehensive mapping of design and experienced-based rules; and re-shaping Front End technical focus from deliverable generation to targeted assurance, value obsession and risk management. While major focus has been on the integration of internal technical and cost applications, significant challenges were also identified in integration of external applications and Application Programming Interface (API) readiness to allow interaction between the applications and the Front End digital application i.e., Concept Factory. And finally, challenges in achieving a high performance team with the right balance of Domain, translators and programmers will be discussed.
IOT Technology Demonstration in ADNOC Onshore Fields. Real Time Monitoring at a Minimum Cost
Authors: Liebeck Martin , AlShehhi Shamma , Hariz Mohammad , Hammadi Khaled Eissa , Camacaro Alfredo Eduado Freites , Al Baloushi Mahdi Abdulla , AlShmakhy Ahmed , Salamitou Philippe , Gambier Philippe , Villegas Humberto , Bertone Javier
Published: December 2021

In brownfields, controlling well integrity is critical in maintaining production and ensuring safety of the personnel and infrastructures. Equally important is optimizing and allocating production in wells by closely following wellhead upstream pressures (and temperatures). In the current situation, field crews have to move from well to well. This method is time consuming, exposes personnel to driving hazards and potentially dangerous areas. In addition, human reading of manual pressure gauges can result in large discrepancy in the reported values. Together with the low frequency of manual readings, this method does not allow for pro-active well intervention and can result in higher downtime in case of well tripping. Deploying remote monitoring with classical telemetry in fields with limited telecommunication infrastructure is costly and complex.

Low Range Wide Area Network (LoRaWAN), a public wireless network technology developed in 2009, changes the situation. It enables low power compact battery sensors with up to 10 km radio range. This performance is sufficient to connect, in one go, most onshore wells without power nor connectivity.

This paper describes a pilot project to evaluate the adequacy of this technology in ADNOC Onshore fields. The objective is to assess performance of LoRaWAN deployed Sensors along four metrics: deployment time, deployment cost, Base station radio coverage and data availability. The pilot uses a plug-in ATEX- certified Wireless Pressure and Temperature (P&T) sensors developed by the vendor SRETT, commercial LoRaWAN Base stations, and proprietary software to provide remote access to the data via cloud data storage and web based application.

For this pilot, four Base stations were deployed in two giant oil fields collecting data from four well heads each equipped with two sensors (P&T). This combination allowed testing wireless link quality over eight radio paths, some with terrain obstacles between Sensors and Base stations. The complete system was fully tested and validated at the shop prior to field deployment. Performances during the deployment was evaluated, and Sensor behaviors were monitored over a three-month period.

In the current environment, maintaining a high HSE standard on aging infrastructure must be made at a controlled cost. LoRaWAN IoT remote monitoring technology is cost effective and efficient to deploy. Once deployed, it will enable preventative safe detection of wells with potential issues, improved accuracy and understanding of production events and lead to a reduction of potential adverse situations thanks to an optimized intervention strategy.
Geochemical Techniques to Detect Sources of Fluids in Highly Pressured Casing-Casing Annuli CCA
Authors: Birkle Dr. Peter , AlRamadan Hamdi A.
Published: December 2021

The buildup of high casing-casing annulus (CCA) pressure compromises the well integrity and can lead to serious incidents if left untreated. Potential sources of water causing the elevated CCA pressure are either trapped water in the cement column or water from a constant feeding source. This study utilizes inorganic geochemical techniques to determine the provenance of CCA produced water as trigger for high pressure in newly drilled wells. Affinities in the hydrochemical (major, minor and trace elements) and stable isotopic (δ2H, δ18O) composition are monitored to identify single fluid types, multi-component mixing and secondary fluid alteration processes. As a proof-of-concept, geochemical fingerprints of CCA produced water from three wells were correlated with potential source candidates, i.e., utilized drilling fluids (mud filtrate, supply water) from the target well site, Early - Late Cretaceous aquifers and Late Jurassic - Late Triassic formation waters from adjacent wells and fields. Geochemical affinities of CCA water with groundwater from an Early Cretaceous aquifer postulate the presence one single horizon for active water inflow. Non-reactive elements (Na, Cl) and environmental isotopes (δ2H, δ18O) were found to be most suited tools for fluid identification. 2H/1H and 18O/16O ratios of supply water and mud filtrate are close to global meteoric water composition, whereas formation waters are enriched in 18O. Elevated SO4 and K concentrations and extreme alkaline conditions for CCA water indicates the occurrence of minor secondary alteration processes, such the contact of inflowing groundwater with cement or fluid mixing with minor portions of KCl additives. The presented technology in this study enables the detection of high CCA pressure and fluid leakages sources, thereby allowing workover engineers to plan for potential remedial actions prior to moving the rig to the affected well; hence significantly reducing operational costs. Appropriate remedial solutions can be prompted for safe well abandonment as well as to resume operation at the earliest time.
Enhancing Indoor Air Quality and Tackling COVID - 19 Virus
Authors: Al Awadhi Ibrahim , Sharma Ashok , Karim Twana
Published: December 2021

Objective/Scope

One of the main concerns of Oil & Gas Plants and associated Buildings is how to improve indoor air quality (IAQ) and tackling viruses. IAQ can be affected, or may become under high risk by some of nearby gases, microbial contaminates or energy stressor that affect the HSE condition. This paper presents the main factors that been considered to provide practical solutions to achieve high IAQ and tackling viruses (such as COVID-19).

Methods, Procedures, Process

IAQ refers to the air quality within and around the plants/buildings. IAQ can usually be affected, or may become under high risk by nearby gases, particulates, microbial contaminates or any mass that affect 100% HSE. Inadequate air quality in building will increase the risk and impact on transferring viruses to people (such as COVID and Flue) and equipment performance (such as equipment failure, components corrosion and short circuits on control board). Survey and data was recorded to evaluate air quality performance in atmosphere instead of assuming it. Accordingly, the impact of inadequate IAQ was studied and evaluated.

Results, Observations & Conclusions

The international standard set a good IAQ in respect of gas concentration and human who works inside buildings in a way that less than 50% people should not detect any odor, 25% should not experience discomfort, 10% should not suffer from mucosal irritation and 5% should not experience annoyance. Study concluded that inadequate IAQ inside the building will affect people performance/health and installed equipment performance. In addition, improper HVAC system operation will be become breeding site for odor causing mold and bacteria, specifically on cooling coil. Hence, several technics were studied to improve IAQ, by installing Ultraviolet (UV) light to stop growing bacterial inside the HVAC system, installing chemical filter in air intakes to remove atmospheric dust, gases and bacteria by 100%, upgrading filtration efficiency to MERV-13 or highest achievable to capture at least 75 – 95% of airborne particles between 0.3 and 1.0 micron, increase outdoor air ventilation and temperature/humidity control.

The performance of HVAC system and quality of air inside building were monitored by simulating IAQ based on ISO 16890, filters life cycle, energy consumption, and the results were found 100% satisfactory and provided solutions that are now successfully implemented in all new and some of the existing buildings.

Novel/Additive Information

There are several buildings with similar issues and these approach/technics now being adopted in new constructed/existing buildings to protect human and asset integrity, which will support ADNOC Way by sustaining safe environment operation, lower health risk, reduce of equipment failure, reduce maintenance cost and 100% HSE. There are numbers of occupied buildings across the world were surrounded by aggressive gases/pollution with poor IAQ and above approaches it can be followed to realize larger benefits.
Predicting the Productivity Enhancement After Applying Acid Fracturing Treatments in Naturally Fractured Reservoirs Utilizing Artificial Neural Network
Authors: Hassan Amjed Mohamed , Aljawad Murtada Saleh , Mahmoud Mohamed Ahmed
Published: December 2021

Acid fracturing treatments are conducted to increase the productivity of naturally fractured reservoirs. The treatment performance depends on several parameters such as reservoir properties and treatment conditions. Different approaches are available to estimate the efficacy of acid fracturing stimulations. However, a limited number of models were developed considering the presence of natural fractures (NFs) in the hydrocarbon reservoirs. This work aims to develop an efficient model to estimate the effectiveness of acid fracturing treatment in naturally fractured reservoirs utilizing an artificial neural network (ANN) technique.

In this study, the improvement in hydrocarbon productivity due to applying acid fracturing treatment is estimated, and the interactions between the natural fractures and the induced ones are considered. More than 3000 scenarios of reservoir properties and treatment parameters were used to build and validate the ANN model. The developed model considers reservoir and treatment parameters such as formation permeability, injection rate, natural fracture spacing, and treatment volume. Furthermore, percentage error and correlation coefficient were determined to assess the model prediction performance. The proposed model shows very effective performance in predicting the performance of acid fracturing treatments. A percentage error of 6.3 % and a correlation coefficient of 0.94 were obtained for the testing datasets. Furthermore, a new correlation was developed based on the optimized AI model. The developed correlation provides an accurate and quick prediction for productivity improvement. Validation data were used to evaluate the reliability of the new equation, where a 6.8% average absolute error and 0.93 correlation coefficient were achieved, indicating the high reliability of the proposed correlation.

The novelty of this work is developing a robust and reliable model for predicting the productivity improvement for acid fracturing treatment in naturally fractured reservoirs. The new correlation can be utilized in improving the treatment design for naturally fractured reservoirs by providing quick and reliable estimations.
A Customized High Performance Water-Based Mud Solved the Challenge to Drill Reactive Shale Formation and Simplify the Logistic Challenge in an Exploration Well in Offshore East Kalimantan, Indonesia
Authors: Pinartjojo Djoko , Hutahaean Edison Tamba Tua , McManus Ian , Nerwan Aphrizal S. I. N. , Hansen Rudiny
Published: December 2021

Exploration drilling obviously requires a robust drilling fluid system to be a key factor in overcoming both the known and unexpected challenges of a structure that consists of reactive clay and lost circulation zones. Extra consideration has to be given to regulatory environmental requirements and complications resulting from regional politics. A High-Performance Water Based Mud (HPWBM) system was selected to address the aforementioned issues.

The HPWBM was customized to respond to the subsurface conditions with the main requirement to provide maximum shale inhibition through a non-dispersed environment. Polyamine was utilized to stabilize all types of clay; an encapsulation polymer and a non-ionic polymer were included to prevent dispersion and to seal micro-fractures. A complete shale study was performed to determine the optimum concentration of the base fluid and each shale inhibitor. Then hydraulic behaviour of the mud was simulated with contractor proprietary software to understand the parameters for optimal hole cleaning as well as Equivalent Circulating Density (ECD) simulation.

The HPWBM system successfully facilitated the execution of the exploration well and provided highly effective clay stabilization. No Non-Productive Time (NPT) was recorded as a result of reactive clay issues. The mud system also facilitated a good rate of penetration (ROP), formation stability, and lubricity. Waste cuttings transportation was not required. In addition, there is also no requirement for costly base oil including its associated transportation costs. The successful implementation of the HPWBM yielded an estimating saving of 25% compared to invert emulsion fluids, prior to considering costs associated with an expensive Liquid Mud Plant (LMP), environmental, and freight costs. Significant cost savings were achieved by eliminating the need for LMP rental, mobilization and demobilization. Another notable saving was realized from the reduced system maintenance of the HPWBM as less dilution was required compared to a regular Water Based Mud.

Thinking outside of the box and embracing the departure from the default consideration of an invert system with a thorough risk assessment augmented value to wellbore construction. A smartly designed HPWBM system provided performance comparable to an invert emulsion system but with superior benefits with respect to environmental protection, simplified logistics and lower costs.
Polymer Outage Strategy for On-Going Polymer Injection Operation in the Sultanate of Oman
Authors: Svec Yi , Kindi Osama , Sawafi Marwan , Farajzadeh Rouhi , Al Sulaimani Hanaa , Van Berkel Jasper , Al-Hinai Suleiman , Al Abri Moh’d , Nofli Sami , Al-Yahyai Ahmed , Al-Mahrooqi Majid
Published: December 2021

Polymer outage (or polymer injection unavailability) is undesirable but also inevitable. When it happens, the question is how to respond to it to minimize its adverse impact on the production. This paper presents the rationale for generating a polymer outage strategy to operate a polymer flood field in the southern area of the Sultanate of Oman. The work presented here is based on field performance and analytical analysis. The diagnostic plots were created from 10 years of polymer flood field response and were used for this operating decision. The pros and cons of two scenarios were discussed. The selected operational strategy is to minimize the short falls of polymer outage. The strategy was implemented in the field.

Simultaneous injection and production pause (SIPP) is recommended for the full field polymer outage. It minimizes the impact on polymer incremental oil and hence less deferment. Calibrated with the actual results, analytical method is used to determine when to shut down and whether a short of buffer period of water can be tolerated before SIPP is carried out.

The polymer literature focus on polymer mechanisms, modeling, project initiation and implementation but no paper discusses the operational strategy on how to respond to field polymer outages. This paper shares our operational learnings and the field results of various polymer operation modes on polymer incremental oil. The learning from this field may be of interest to other operators who are planning or currently implementing polymer flood in their fields.
Temporal Dynamics of Microcystins In Two Reservoirs With Different Trophic Status During The Early Growth Stage of Cyanobacteria
Authors: Xue Qingju , Kong Ming , Xie Liqiang , Li Tong , Liao Mengna , Yan Zebin , Zhao Yanyan
Published: December 2021

Harmful cyanobacterial blooms are increasing in frequency and severity, which makes their toxic secondary metabolites of microcystins (MCs) have been widely studied, especially in their distribution and influence factors in different habitats. However, the distribution of MCs on the early growth stage of harmful cyanobacteria and its influence factors and risks are still largely unknown. Thus, in the present study, two reservoirs (Lutian Reservoir and Lake Haitang) with different trophic status in China have been studied weekly from March to May in 2018, when the cyanobacteria communities were just in the early growth stage, to investigate the variation of MCs concentration and the relationships between MCs and environmental parameters. During the investigation, Lutian Reservoir and Lake Haitang were found to be mesotrophic and light eutrophic, respectively. In Lutian Reservoir, the concentration of EMCs was obviously higher than that of IMCs with a mean value of 0.323 and 0.264 μg/L, respectively. Meanwhile, the concentration of EMCs also fluctuated more sharply than that of IMCs. Congeners of IMC-YR and EMC-LR were respectively dominant in total concentrations of IMCs and EMCs. Unsurprisingly, in Lake Haitang, the concentrations of IMC and EMC were both significantly higher than that in Lutian Reservoir with a mean concentration of 0.482 and 0.472 μg/L, respectively. Differently, the concentration of MC-YR was dominant in both IMCs and EMCs, followed by MC-LR. In correlation analysis, the IMCs were significantly and positively correlated with the density and biomass of phytoplankton phyla and potential MCs-producing cyanobacteria and the parameters of water temperature (WT), nutrients and organic matters. Similar results were also observed for EMCs. While the different variation of MCs in two reservoirs might be primarily caused by the differences in WT, nutrients (especially phosphorus), organic matters and the composition of MCs-producing cyanobacteria. In addition, the coexistence of the dominant species of Pseudoanabaena sp., which can produce taste-and-odor compound of 2-methylisoborneol (2-MIB), might have significant impacts on the concentration and toxicity of MCs. Our results suggested that the risks posed by MCs at the early growth stage of cyanobacteria should also deserve our attentions, especially in mesotrophic water bodies.
Harmonizing Surface Reflectance Between Landsat-7 ETM+, Landsat-8 OLI, and Sentinel-2 MSI
Authors: Cao Hongye , Han Ling , Li Liangzhi
Published: December 2021

Remote sensing dynamic monitoring methods often benefit from a dense time series of observations. To enhance these time series, it is sometimes necessary to integrate data from multiple satellite systems. For more than 40 years, Landsat has provided the longest time record of space-based land surface observations, and the successful launch of the Landsat-8 Operational Land Imager (OLI) sensor in 2013 continues this tradition. However, the 16-day observation period of Landsat images has challenged the ability to measure subtle and transient changes like never before. The European Space Agency (ESA) launched the Sentinel-2A satellite in 2015. The satellite carries a Multispectral Instrument (MSI) sensor that provides a 10-20m spatial resolution data source providing an opportunity to complement the Landsat data record. The collection of Sentinel-2A MSI, Landsat-7 ETM+, and Landsat-8 OLI data provide multispectral global coverage from 10m to 30m with further reduced data revisit intervals. There are many differences between sensor data that need to be taken into account to use these data together reliably. The purpose of this study is to evaluate the potential of integrating surface reflectance data from Landsat-7, Landsat-8 and Sentinel-2 archived in the Google Earth Engine (GEE) cloud platform. To test and quantify the differences between these sensors, hundreds of thousands of surface reflectance data from sensor pairs were collected over China. In this study, some differences in the surface reflectance of the sensor pairs were identified, based upon which a cross-sensor conversion model was proposed, i.e., a suitable adjustment equation was fitted using an ordinary least squares (OLS) linear regression method to convert the Sentinel-2 reflectance values closer to the Landsat-7 or Landsat-8 values. The regression results show that the Sentinel MSI data are spectrally comparable to both types of Landsat image data, just as the Landsat sensors are comparable to each other. The root mean square error (RMSE) values between MSI and Landsat spectral values before coordinating the sensors ranged from 0.014 to 0.037, and the RMSE values between OLI and ETM + ranged from 0.019 to 0.039. After coordination, RMSE values between MSI and Landsat spectral values ranged from 0.011 to 0.026, and RMSD values between OLI and ETM + ranged from 0.013 to 0.034. The fitted adjustment equations were also compared to the HLS (Harmonized Landsat-8 Sentinel-2) global fitted equations (Sentinel-2 to Landsat-8) published by the National Aeronautics and Space Administration (NASA) and were found to be significantly different, increasing the likelihood that such adjustments would need to be fitted on a regional basis. This study believes that despite the differences in these datasets, it appears feasible to integrate these datasets by applying a linear regression correction between the bands.
Comparative Study of Ensemble Models of Deep Convolutional Neural Networks for Crop Pests Classification
Authors: su zhongbin , luo jiaqi , wang yue , kong qingming , dai baisheng
Published: December 2021

Pest infestations on wheat, corn, soybean, and other crops can cause substantial losses to their yield. Early diagnosis and automatic classification of various insect pest categories are of considerable importance for accurate and intelligent pest control. However, given the wide variety of crop pests and the high degree of resemblance between certain pest species, the automatic classification of pests can be very challenging. To improve the classification accuracy on publicly available D0 dataset with 40 classes, this paper compares studies on the use of ensemble models for crop pests classification. First, six basic learning models as Xception, InceptionV3, Vgg16, Vgg19, Resnet50, MobileNetV2 are trained on D0 dataset. Then, three models with the best classification performance are selected. Finally, the ensemble models, i.e, linear ensemble named SAEnsemble and nonlinear ensemble SBPEnsemble, are designed to combine the basic learning models for crop pests classification. The accuracies of SAEnsemble and SBPEnsemble improved by 0.85% and 1.49% respectively compared to basic learning model with the highest accuracy. Comparison of the two proposed ensemble models show that they have different performance under different condition. In terms of performance metrics, SBPEnsemble giving accuracy of classification at 96.18%, is more competitive than SAEnsemble.
Disruption of Proprioceptive Information During Electrical Stimulation of the Cutaneous Afferents
Authors: Katic Natalija , Balaguer Josep-Maria , Gorskii Oleg , Pavlova Natalia , Karal-ogly Dzhina , Bulgin Dmitry , Orlov Sergei , Musienko Pavel , Raspopovic Stanisa , Capogrosso Marco
Published: December 2021

Restoration of proprioception with neurotechnology is critical to improve effectiveness of robotic neuro-prostheses. Unfortunately, after initial enthusiasm clinical results showed that unlike touch, proprioception could not be reliably induced. Here we show that concurrent activation of multiple sensory modalities may trigger unwanted sensory regulation mechanisms that disrupt proprioception. We recorded intra-spinal neural activity induced by stimulation of proprioceptive afferents from the radial nerve in three monkeys. Then, we superimposed stimulation of the radial nerve cutaneous branch and quantified its impact on spinal neural activity via population analysis. Proprioceptive pulses produced robust neural trajectories in the neural manifold that were disrupted by concurrent stimulation of cutaneous afferents. This disruption correlated with a reduction of afferent volleys and multi-unit activity both in the spinal cord and somatosensory cortex. Our results suggest that limited specificity not only impacts localization of artificial percepts, but also their nature to an extent that was never considered.
Lycium Barbarum Polysaccharides Regulate the Gut Microbiota To Modulate Metabolites in High Fat Diet-Induced Obese Rats
Authors: Fan Yanna , Yan Lu , Li Mengyao , Pu Zhiyu , Zhang Yannan , Yang Jianjun
Published: December 2021

Previous studies had indicated that the gut microbiota was a main internal factor leading to obesity through energy storage and metabolic disorders. Lycium Barbarum Polysaccharides (LBP) have been discovered with a more protective effect on intestinal flora. But it is unclear whether LBP could regulate the gut microbiota to modulate metabolites, finally relieving obesity. A related study of high-throughput 16S rRNA sequencing and serum metabolomics profiling in LBP intervention on high fat diet-induced obese rats then explored the beneficial effects of LBP and the underlying mechanism. LBP affected lipid parameters such as total cholesterol, Triglyceride, and High-density lipoprotein. The gut microbiota result detected 16 types of the phylum of bacteria in total, while four of them (Bacteroidetes, Firmicutes, Proteobacteria, Deferribacteres) were significantly different. LBP upregulated the level of Firmicutes of obese rats. LBP might associate with the gut microbiota that participates in the membrane transport and metabolism of amino acid, carbohydrate, energy, and lipid. The serum metabolomics profiling of high-fat diet-induced obesity rats found over 30 differential metabolites between model and intervention groups. Primary metabolites include cortisol, glycohyocholic acid, homo-L-arginine, ursodeoxycholic acid, isoursodeoxycholic acid, glycoursocholic acid, 4-ethylphenylsulfate, deoxycholic acid, 7-hydroxy-3-oxocholanoic acid isomers, gly-phe, pipecolic acid, proline betaine, and pyrocatechol sulfate. Pathway analysis in serum found four disorder pathways: glycerophospholipid metabolism, glycine-serine-threonine metabolism, biosynthesis of unsaturated fatty acids, and linoleic acid metabolism. The studies revealed that LBP treatment increased the diversity of fecal microorganisms and reduced metabolic disorders in obese rats. LBP ameliorated metabolic disorders and rebalanced the gut microbiome.
Working Mechanism of Remdesivir and Discovering New Potential Inhibitors to SARS-CoV-2 RNA-Dependent RNA Polymerase (RdRp) using High-Throughput Virtual Screening and Molecular Dynamics Simulations .
Authors: Brunt Dylan , Lakernick Phillip , WU CHUN
Published: December 2021

RNA-dependent RNA polymerase (RdRp), is an enzyme essential component in the RNA replication within the life cycle of the severely acute respiratory coronavirus-2 (SARS-CoV-2), causing the deadly respiratory induced sickness COVID-19. Remdesivir is a prodrug that has seen some success in inhibiting this enzyme, however there is still the pressing need for effective alternatives. In this study, we present the discovery of four non-nucleoside small molecules that bind favorably to RdRp over adenosine-triphosphate (ATP) and active-form remdesivir-triphosphate (RTP) using high-throughput virtual screening (HTVS) coupled with extensive (total 4800 ns) molecular dynamics (MD) simulations with using the ZINC compounds database against SARS-CoV-2 RdRp (PDB: 7BV2). We found that the simulations with both ATP and RTP remained stable for the duration of their trajectories, and it was revealed that the phosphate tail of RTP was stabilized by a positive amino acid pocket near the entry channel of RTP and magnesium ions containing residues K551, R553, R555 and K621. It was also found that residues D623, D760, and N691 further stabilized the ribose portion of RTP with U10 on the template RNA strand forming hydrogen pairs with the adenosine motif. Using these models of RdRp, we employed them to screen the ZINC database of ~17 million molecules. Using docking and drug properties scoring, we narrowed down our selection to fourteen candidates. These were subjected to 200 ns simulations each underwent free energy calculations. We identified four hit compounds from the ZINC database that have similar binding poses to RTP while possessing lower overall binding free energies, with ZINC097971592 having a binding free energy two times lower than RTP.
Renoprotective Effects of Metformin and Its Relationship with Oxidative Stress in Type 2 Diabetic Mice
Authors: Wenjie Wen , Qilun Zhang , shuangjie Bi , Jingfan Xue , Xiaoying Wu , Wan Zhou , Wei Wang , Shandong Ye
Published: December 2021

Background: Oxidative stress has previously been shown to play critical roles in the development of diabetes and its complications. The purpose of this research was to observe the reno-protective effect of metformin and its effect on oxidative stress in type 2 diabetic mice renal tissue.Methods: Type 2 diabetes mellitus mice model was established by High-fat feed combined with small-dose STZ and randomly divided into diabetes model group, Metformin [MET, 250mg/(kg.d)] group, Glibenclamide (GLIB) [GLIB, 2.5mg/(kg.d)] group, and normal control group (NC). After 8 weeks of intervention, blood and urine samples were collected for detection of FBG, HbA1c, urine albumin (Alb), retinol-binding protein (RBP), podocalyxin (PCX), 8-OHdG, 8-iso-PG, and creatinine (Cr). Renal tissue specimens were preserved for observing renal glomerular basement membrane thickness (GBMT) and foot process fusion rate (FPFR) under electron microscopy.Results: Compared with the NC group, FBG, HbA1c, urinary Alb/Cr (UACR), RBP/Cr (URCR), PCX/Cr (UPCR), 8-OHdG /Cr (UOHCR), and 8-iso-PG /Cr (UISOCR) significantly increased in the T2DM group (P <0.05). Compared with the T2DM group, FBG, HbA1c, UACR, URCR, UPCR, UOHCR, and UISOCR were significantly reduced in the GLIB group and MET group (P <0.05). Compared to the GLIB group, UACR, URCR, UPCR, UOHCR, and UISOCR decreased in the MET group (P <0.05), but FBG and HbA1c were not differenced statistically between the two groups. GBMT and FPFR increased in the T2DM group (P <0.05), which were reduced in the MET group and lighter than those in the GLIB group (P <0.05).Conclusion: Metformin intervention can play a reno-protective effect in type 2 diabetic mice, which may be related to its effect in inhibiting enhanced oxidative stress in vivo.
Time-Based Factory Efficiency Analysis | I.C. Engine Assembly Line
Authors: Tailony Rauf , Tailony Ishaq
Published: December 2021

Cold test stations are commonly arranged as sequential processes along a complete engine production line. The production line consists of several stations for engine building purposes, and before the engine exits the production line it passes through different validation and testing stations, such as leak testing stations, piston protrusion stations (known as torque to turn stations), and cold test stations. Each of these stations has a sequence of operation that is performed automatically or semi-automatic with the support of an operator. The waiting time until the engine finishes the operation in one station is called “cycle time”. The longer the cycle time the less efficient the production line. Cold testing stations are considered the most complicated and time-consuming, yet important test stations for engine and powertrain development. The lengthy cycle time affects the overall efficiency of the production line. This paper investigates the problem of the cycle time difference between consequent stations and its effect on the overall efficiency of the factory. New techniques and operations research methods are introduced aiming to recover from such a manufacturing obstacle. This research is investigating the limitations of a manufacturing operation standpoint. Each test station is treated as a block that simulates the actual station, and the overall factory workflow is described. Time-based equations governing block time, idling time, and utilization of the system are introduced, and the factory efficiencies are calculated and compared. After identifying the problem, a practical solution is explained.
Wideband Spectrum Sensing Based on Advanced Sub-Nyquist Sampling Structure
Authors: Wang Xue , Chen Qian , Jia Min , Gu Xuemai
Published: December 2021

As the bandwidth increases, the high-speed sampling rate becomes the bottleneck for the development of wideband spectrum sensing. Wideband spectrum sensing with sub-Nyquist sampling attracts more attention and modulated wideband converter (MWC) is an attractive sub-Nyquist sampling system. For the purpose of breaking the system structure limit, an advanced sub-Nyquist sampling framework is proposed to simplify the MWC system structure, adopting the single sampling channel structure with a frequency shifting module to acquire the sub-Nyquist sampling values. In order to recover the signal support information, the sensing matrix must be built according to the only one mixing function. Most existing support recovery methods rely on some prior knowledge about the spectrum sparsity, which is difficult to acquire in practical electromagnetic environment. To address this problem, we propose an adaptive residual energy detection algorithm (ARED), which bypasses the need for the above-mentioned prior knowledge. Simulation results show that, without requiring the aforementioned prior knowledge, the ARED algorithm, which is based on the advanced sub-Nyquist sampling framework, has the similar performance as MWC and even higher than MWC in some cases.
Analysis of the Early Clinical Effect of Simultaneous Ipsilateral Total Hip and Knee Arthroplasty in the Treatment of End-stage Hemophilic Arthritis
Authors: Peng Xu , Chen Shirong , Cheng Xiangjun , Xie Xiaowei , Nie Mao
Published: December 2021

ObjectiveTo evaluate the clinical efficacy of simultaneous ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) in the treatment of advanced hemophilic arthritis. Methodthe clinical data of 8 patients with advanced hemophilic arthritis, with ages of 31.6±6.2 years (ranging from 25-38 years, who underwent ipsilateral THA and TKA at the ** Hospital from January 2018 to May 2021 were retrospectively analyzed. There were 6 cases of hemophilia A and 2 cases of hemophilia B. The preoperative level of coagulation factor VIII was 1.8(±1.3)%，activated partial prothrombin time (aPTT) was 131.2 (±35.3) s. A comparison of the Harris score before and 0.3-1 year after operation was performed to evaluate hip function, American hospital for special surgery (HSS) knee score and American Knee society score (KSS) score. ResultDuring the follow-up period of 1.4 (± 1.1) years, no intra-articular bleeding and skin dehiscence were found in the early postoperative period, and no joint infection, bleeding, prosthesis loosening and sinking were found in the last follow-up visit. The Harris score increased from 16.8 (± 4.4) preoperatively to 77.6 (± 7.1) postoperatively, HSS knee score increased from 41.8 (± 4.2) preoperatively to 76.0 (± 5.8) postoperatively, the clinical KSS increased from 35.6 (± 10.8) preoperatively to 79.2 (± 6.9) postoperatively. The KSS increased from 22.8 (± 8.4) preoperatively to 72.0 (± 5.9) postoperatively at the last follow-up visit. The differences were statistically significant (P < 0.05).ConclusionsIpsilateral THA and TKA in the treatment of advanced hemophilic arthritis can effectively relieve pain, and improve hip and knee joint function, as well as the quality of life, and can thus be recommended as a safe and effective measure for the treatment of advanced hemophilic arthritis.
Hydrogen Isotope Effect on Self-Organized Radial Electric Field Criticality During Electron Internal Transport Barrier Formation in Toroidal Plasmas
Authors: Kobayashi Tatsuya , Shimizu Akihiro , Nishiura Masaki , Ido Takeshi , Satake Shinsuke , Tokuzawa Tokihiko , Tsujimura Toru , Nagaoka Kenichi , Ida Katsumi
Published: December 2021

Self-organized structure formation in magnetically confined plasmas is one of the most attractive subjects in modern experimental physics. Nonequilibrium media are known to often exhibit phenomena that cannot be predicted by superposition of linear theories. One representative example of such phenomena is the hydrogen isotope effect in fusion plasmas, where the larger the mass of the hydrogen isotope fuel is the better the plasma confinement becomes, contrary to what simple scaling models anticipate. In this article, threshold condition of a plasma structure formation is shown to have a strong hydrogen isotope effect. To investigate the underlying mechanism of this isotope effect, the electrostatic potential is directly measured by a heavy ion beam probe. It is elucidated that the positive radial electric field structure can be driven by less input power normalized by plasma density in plasmas with larger isotope mass across the structure formation.
Anatomical Patterns of the Nasopalatine Canal and Incisive Foramen in an African Setting – a Cross-sectional Study
Authors: Sarna Krishan , Estreed Merna Akram , Sonigra Khushboo Jayant , Amuti Thomas , Opondo Florence , Kamau Martin , Ngeow Wei Cheong
Published: December 2021

Purpose: Surgical procedures revolving around the anterior maxilla are of great interest due to their debilitating facial aesthetics and nerve injury effects if complications arise. Hence, sufficient knowledge concerning the morphology and morphometry of the nasopalatine canal (NPC) and incisive foramen (IF) is necessary to prevent such complications from arising. Materials and Methods: Measurements of the NPC and the IF were carried out on 150 CBCT scans. The maxillary bone thickness anterior to the NPC was measured at 3 levels. Independent t-test and chi-square test were performed to determine the presence of sexual dimorphism. Results: The presence of one Stenson’s foramen was most prevalent. The mean length of NPC was 13.21 ± 3.25 mm with significantly longer canals in males. The most prevalent shape of NPC was cylindrical in sagittal view and a single canal in coronal view. The mean angulation of NPC was 118.42° to the horizontal plane. The average dimensions of the IF were 3.53 mm and 3.07 mm in the anteroposterior and mediolateral diameter respectively while the most common shape was round. The anterior maxillary bone was thicker in males and generally reduced in thickness from the anterior nasal spine superiorly towards the alveolar crest inferiorly. Conclusion: This study highlights the anatomical characteristics of the NPC and IF, with significant sexual dimorphism observed regarding the number of Stenson’s foramina, length of NPC, shapes of the NPC and IF as well as alveolar bone thickness anterior to NPC.
Tailoring Optical Bistability In Nonlinear Photonic Crystals Based on Metallic Nanoparticles And Graphene
Authors: Naseri Tayebeh , Adl Hamid Pashaei
Published: December 2021

In this work, we revisit the optical response of a one-dimensional photonic crystal consisting of graphene monolayers and a plasmonic nanocomposite as a defect layer in the structure. By taking advantage of the modified transfer matrix approach, the analytical solution of the light transmission and field distribution of the photonic crystal are evaluated. Besides, by considering one of the layers as a Kerr-nonlinear medium, we delve into optical bistability phenomenon in the model for two different cases. Our numerical results reveal that the proposed photonic crystal can enhance the field distribution and reduce the optical bistability’s threshold in comparison to the conventional photonic crystals. Furthermore, the optical bistable switch-up and switch-down thresholds of the proposed resonator can be tailored flexibly by plasmon-plasmon interactions in the defect layer. Finally, the electric field distribution amelioration and optical bistability by means of graphene layers in the structure are attainable. The influences of the parameters such as the graphene and the nanocomposite on the performance of OB are analyzed and compared in the two different cases. Therefore, present approach can lay the groundwork for designing highly sensitive surface plasmon resonance biosensors and switches where the proposed technique may find unprecedented capabilities.
Evaluation of Microwave-Assisted Organic Acid Separation of Organic Sulfur from High Sulfur Coal
Authors: Jiang Chaoshun , Liu Jin , Hao Shen , Pang Zheng , Wang Zhi , Li Ping , Xing Xing
Published: December 2021

To explore the feasibility of organic acid removal of organic sulfur from high sulfur coal, three organic acids, oxalic acid, citric acid and ascorbic acid, were selected as desulfurization reagents. Combined with microwave irradiation technology, desulfurization experiments of high-sulfur coal treated with nitric acid were conducted. The orthogonal experimental results showed that microwave synergistic citric acid desulfurization had a better desulfurization effect. The removal rate of organic sulfur was 55.47% when the operation conditions of the reaction were 1 mol/L, 90 ℃ and 1000 W for 7 min. The desulfurization efficiency of oxalic acid and ascorbic acid was not good, and the removal efficiencies of organic sulfur were 32.35% and 21.37%, respectively. Fourier transform infrared spectroscopy showed that sulfones and sulfoxides were partially reduced and that the removal effect of thiophene was poor. X-ray photoelectron spectroscopy showed that the mercapto group in the mercaptan combined with hydrogen ions and escaped in the form of H2S. The content of aromatic thioether and aromatic thiol in the coal treated with microwave irradiation was only 0.1%. Research indicates that microwave-assisted organic acid removal of organic sulfur is feasible, and researchers can explore more efficient organic acids as desulfurization reagents based on this study.