bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulating Visuomotor Sequence Learning by Repetitive Transcranial Magnetic Stimulation: What Do We Know So Far?
Authors: Szucs-Bencze Laura , Vekony Teodora , Pesthy Orsolya , Szabo Nikoletta , Kincses Zsigmond Tamas , Turi Zsolt , Nemeth Dezso
Published: November 2021

Sequence learning and statistical learning are key components of predictive processes and many cognitive, motor, and social skills. The Serial Reaction Time Task (SRTT) can measure this fundamental cognitive process in the visuomotor domain. Repetitive transcranial magnetic stimulation (rTMS) is an increasingly used non-invasive brain stimulation method that can help us to determine the functional role of a given brain region. In this literature review, we systematically analyzed the eligible records (n = 17) that sought to modulate the performance on the SRTT with rTMS. The purpose of the analysis was to determine the effects of the following factors on SRTT performance: (1) stimulated brain areas, (2) rTMS protocols, (3) stimulated hemisphere, (4) timing of the stimulation, (5) SRTT sequence properties, and (6) other methodological features. We found that the two most promising target areas are the primary motor cortex (M1) and the dorsolateral prefrontal cortex (DLPFC). Low-frequency protocols over the M1 usually weakened performance, but the results are less consistent for the DLPFC. Our analysis of these six factors could help design future studies to modulate sequence learning by non-invasive brain stimulation.
Precipitation Forecast Characteristics of Radar Data Assimilation Based on Precipitation Types
Authors: Bae Jeong-Ho , Min Ki-Hong
Published: November 2021

Radar observation data with high temporal and spatial resolution are used in the data assimilation experiment to improve precipitation forecast of a numerical model. The numerical model considered in this study is Weather Research and Forecasting (WRF) model with double-moment 6-class microphysics scheme (WDM6). We calculated radar equivalent reflectivity factor using higher resolution WRF and compared with radar observations in South Korea. To compare the precipitation forecast characteristics of three-dimensional variational (3D-Var) assimilation of radar data, four experiments are performed based on different precipitation types. Comparisons of the 24-h accumulated rainfall with Automatic Weather Station (AWS) data, Contoured Frequency by Altitude Diagram (CFAD), Time Height Cross Sections (THCS), and vertical hydrometeor profiles are used to evaluate and compare the accuracy. The model simulations are performed with and with-out 3D-VAR radar reflectivity, radial velocity and AWS assimilation for two mesoscale convective cases and two synoptic scale cases. The radar data assimilation experiment improved the location of precipitation area and rainfall intensity compared to the control run. Especially, for the two convective cases, simulating mesoscale convective system was greatly improved.
Psychometric Properties of SCARED-C Scale in a Romanian Community Sample and its Future Utility for Dental Practice
Authors: Bucur Sorana-Maria , Moraru Adela , Adamovits Beata , Bud Eugen Silviu , Olteanu Cristian Doru , Vaida Luminița Ligia
Published: November 2021

SCARED-C instrument (the child version, 41 items) is used for screening anxiety in children between 8 to 18 years old and has been first introduced by Birmaher & collab. in 1995, with good psychometric data - internal consistency from α =.74 to .93 - and good discriminative validity indices in the original versions (1997, 1999). Since then, many countries have adopted the scale, for its utility in identifying five subsets of anxiety disorders (subscales): somatic/panic disorder, generalized anxiety, separation anxiety, social phobia, and school avoidance. The present study contains the first Romanian translated and adapted version of the SCARED-C instrument on a community sample of 477 children (8-18 years old) from Mureș county schools. The instrument showed moderate to good internal consistency (α Cronbach from to .63 to .91 for the total scale) and good test-retest reliability (.70) on a subset of 85 children sample. A confirmatory factorial analysis (CFA) was conducted to test the factor structure of the Romanian version of SCARED-C; results showed that SCARED-C has good psychometric properties to be used for screening anxiety in Romanian children and adolescents. The implications for using SCARED-C in dental practice are discussed. Future studies need to be conducted for exploring convergent and discriminative validity of the instrument and the sensitivity to current DSM-V criteria. Application on a dental pediatric sample is also required.
SiO2 Coated Up-conversion Nanomaterial Doped with Ag Nanoparticles for Micro-CT Imaging
Authors: Zhang Wei , Lu Yanli , ZANG YANG , Han Jinhui , Xiong Qingyun , Xiong Jinping
Published: November 2021

In this study, a new method for synthesizing Ag-NaYF4:Yb3+/Er3+ @ SiO2 nanocomposites was introduced. Using a hydrothermal method, the synthesized Yb3+- and Er3+-codoped NaYF4 upconversion luminescent materials and Ag nanoparticles were doped into upconversion nanomaterials and coated with SiO2 up-conversion nanomaterials. This material is known as Ag-UCNPs-SiO2’ it improves both the luminous intensity because of the doped Ag nanoparticles and has low cytotoxicity because of the SiO2 coating. The morphology of UCNPs was observed using scanning electron microscopy (SEM), and the mapping confirmed the successful doping of Ag nanoparticles. Successful coating of SiO2 was confirmed using transmission electron microscopy (TEM). Fluorescence spectra were used to compare changes in luminescence intensity before and after doping Ag nanoparticles. The reason for the increase in luminescence intensity after doping with Ag nanoparticles was simulated using first-principles calculations. The cytotoxicity of Ag-UCNPs-SiO2 was tested via the cell counting kit-8 (CCK-8) method, and its imaging ability was characterized using the micro-CT method.
Geometric Algebra Framework Applied to Circuits with Non-sinusoidal Voltages and Currents
Authors: Cieśliński Jan , Walczyk Cezary
Published: November 2021

We apply a well known technique of theoretical physics, known as Geometric Algebra or Clifford algebra, to linear electrical circuits with non-sinusoidal voltages and currents. We rederive from the first principles the Geometric Algebra approach to the apparent power decomposition. The important new point consists in a choice of a natural convenient basis in the Clifford vector space which simplifies considerably the presentation. Thus we are able to derive a number of general results which are missing in the former papers. In particular, a natural correspondence with the Current Physical Components approach is shown.
Roles of Land and Topography on Propagating Convective Systems During the Heavy Rainfall Event of the 2002 Jakarta Flood, Indonesia
Authors: Yulihastin Erma , Nuryanto Danang Eko , Muharsyah Robi
Published: November 2021

The movement direction of propagating convective systems originating from both inland and offshore over the north coast of West Java in Indonesia is determined primarily by the prevailing wind. However, the role of a land-sea contrast and a rugged topography over southern West Java is also expected to affect propagating convective systems by increasing land-sea breezes and enhancing upward motion. These hypotheses are tested using a weather prediction model incorporating convection (up to 3 km height) to simulate the heavy rainfall event during 26–29 January associated with the 2002 Jakarta flood. First, we addressed the influence of land-sea contrast and topography on the local circulation, particularly in the area surrounding Jakarta, by replacing the inland topography over western Indonesia (96°–119°E, 17°S–0°) with a water body with an altitude of 0 m. We then compared the results of model simulations with and without topography. The results show that the main role of the topography here is enhancing the upward motion and generating a deep convective cloud in response to the land-based convective system during 26–27 January 2002, which then continuously and rapidly propagates offshore due to the cold pool mechanism. Furthermore, the land-sea contrast has a significant role in increasing sea breeze under the rapidness of the landward propagation system during 28–29 January 2002, which was strengthened by the gravity waves and resulted in early morning convection over coastal regions.
Application of Benford’s Law on Cryptocurrencies
Authors: Vičič Jernej , Tošić Aleksandar
Published: November 2021

Blockchain-based currencies or cryptocurrencies have become a global phenomenon known to most people as a disruptive technology, and a new investment vehicle. However, due to their decentralized nature, regulating these markets has presented regulators with difficulties in finding a balance between nurturing innovation, and protecting consumers. The growing concerns about illicit activity have forced regulators to seek new ways of detecting, analyzing, and ultimately policing public blockchain transactions. Extensive research on machine learning, and transaction graph analysis algorithms has been done to track suspicious behaviour. However, having a macro view of a public ledger is equally important before pursuing a more fine-grained analysis. Benford’s law, the law of first digit, has been extensively used as a tool to discover accountant frauds (many other use cases exist). The basic motivation that drove our research presented in this paper was to test he applicability of the well established method to a new domain, in this case the identification of anomalous behavior using Benford’s law conformity test to the cryptocurrency domain. The research focused on transaction values in all major cryptocurrencies. A suitable time-period was identified that was long enough to sport sufficiently large number of observations for Benford’s law conformity tests and was also situated long enough in the past so that the anomalies were identified and well documented. The results show that most of the cryptocurrencies that did not conform to Benford’s law had well documented anomalous incidents, the first digits of aggregated transaction values of all well known cryptocurrency projects were conforming to Benford’s law. Thus the proposed method is applicable to the new domain.
Effects of a Direct-Fed Microbial and Feedlot Pen Environmental Change on Phenotypic Resistance among Enterococci Isolated from Beef Cattle Feces
Authors: Murray Sarah A. , Holbert Ashlyn C. , Norman Keri N. , Lawhon Sara D. , Sawyer Jason E. , Scott Harvey Morgan
Published: November 2021

In two sequential replicates (n=90 and n=96 feedlot finisher cattle, respectively) we measured the impact of an Enterococcus faecium-based probiotic (DFM) and an altered feedlot pen environment on antimicrobial resistance among fecal enterococci in cattle fed (or, not fed) the macrolide tylosin. Diluted fecal samples were spiral-plated on plain and antibiotic-supplemented m-Enterococcus agar. In the first replicate, tylosin significantly (p<0.05) increased the relative quantity of erythromycin-resistant enterococci. This effect was diminished in cattle fed the DFM in conjunction with tylosin. A similar observed effect was not statistically significant (P > 0.05) in the second replicate. Isolates were speciated and resistance phenotypes were obtained for E. faecium and E. hirae. E. faecium isolates were whole-genome sequenced, which yielded sequence types (ST), resistance genes and phylogeny. Samples of the DFM were sequenced and found to contain E. faecium ST296, which was not present on Day 0 of either replicate. This DFM sequence type was found in fecal samples after Day 0, the majority of which were isolated from cattle in one of the DFM-fed pens. Increased prevalence of ST296 occurred with a concomitant decrease in ST240; of importance, the latter typically harbored both ermB and tet(M) genes.
From Undetectable Equals Untransmittable (U=U) to Breastfeeding: Is the Jump Short?
Authors: Prestileo Tullio , Sanfilippo Adriana , Di Marco Lorenza , Argo Antonina
Published: November 2021

Background: Vertical transmission of HIV infection can occur during pregnancy, during childbirth or through breastfeeding. The recommendations issued by the various international guidelines (WHO 2010, EACS 2017, DHHS 2017) on the safety of breastfeeding of HIV-infected women in effective antiretroviral treatment do not provide univocal indications referring to individual countries the choice to advise or advise against such procedure. Methods: A retrospective study was conducted in a small cohort of HIV-infected pregnant women who, despite the information received, decided to breastfeed their children. The observation was carried out in the period between March 2017 and June 2021. In all newborns, prophylaxis therapy was initiated at birth, according to the treatment guidelines, the scheme adopted involved the administration of zidovudine (AZT) orally for 4 weeks, started immediately after the childbirth. Breastfeeding time was, on average, 5 months. Results: No contagion was diagnosed. All infants were tested for HIV-RNA at birth, 1, 3, and 6 months after birth, and 1, 3 and 3 months after stopping breastfeeding. Conclusions: The data obtained represent, in our opinion, a solicitation to discuss and re-evaluate scientific evidence that starting from "Undetectable Equals Untransmittable" (U = U) can open a scientific and cultural review of breastfeeding.
Provenance Analysis and Structural Study of the Cycladic Blueschist Unit Rocks from Iraklia Island: From the Paleozoic Basement Unroofing to the Cenozoic Exhumation
Authors: Laskari Sofia , Soukis Konstantinos , Lozios Stylianos , Stockli Daniel F. , Poulaki Eirini M. , Stouraiti Christina
Published: November 2021

Detailed mapping and structural observations on the Cycladic Blueschist Unit (CBU) of Iraklia island integrated by detrital zircon (DZ) U-Pb ages elucidate the Mesozoic pre-subduction evolution and the Cenozoic orogenic events. Field data reveal that the Iraklia tectonostratigraphy includes a heterogeneous Lower Schist Unit juxtaposed against a Variegated Marble Unit and an overlying Upper Schist Unit. The contact is an extensional ductile-to-brittle-ductile, top-to-N shear zone, associated with the Oligo-Miocene exhumation. The DZ spectrum of the Lower Schist Unit characterized by Gondwanan/peri-Gondwanan provenance signatures points to Late Triassic maximum depositional ages (MDAs). A quartz-rich schist layer yielded Precambrian DZ ages exclusively, considered part of the pre-Variscan metasedimentary Cycladic Basement, equivalent to those observed on Ios island. A significant change occurred during the deposition of the Upper Schist Unit, revealing Late Cretaceous MDAs and a high amount of Late Paleozoic DZ ages, attesting to more internal Pelagonian source areas. The imprint of Paleotethyan vs. Neotethyan geodynamic events is revealed in the DZ U-Pb ages record. The Triassic DZ input demonstrates eroded volcanic material related to the final Paleotethys closure and the Pindos/CBU rift basin opening. Late Cretaceous metamorphic/magmatic zircons and ~48-56 Ma zircon rims constrain the onset of subduction and high-pressure metamorphism.
Do we Understand Sustainability? An Architectural Insight Into the Origin of the Concept
Authors: Mondal Tushar
Published: November 2021

Sustainability is a concept shrouded in abstraction. While we have definitions in existence, it is often difficult to explain the concept itself. The current definition of ‘sustainable development’ was given by the Brundtland Commission’s report in 1987. The Earth Summit at Rio in 1992 gave us Agenda 21, an action plan to achieve sustainable development. Now in the 21st century, philosophers, academicians, and researchers across the globe are paving the way for a new understanding of the term ‘sustainability’, its contextual nature, and its relation to humans, politics, and ecology. This article investigates the origins of the term ‘sustainability’, its derivatives, and the concept of sustainable development. A semantical analysis is carried out to understand the differences between ‘sustainability’ and ‘sustainable development’. Next, the development of the three pillars of sustainability and the application of these concepts in the field of architecture and design is also investigated.
Synthesis of Carbon Nanotubes via Liquid Injection Chemical Vapour Deposition as a Vector for the Chemical Recycling of Waste Composite Carbon Sources
Authors: Orbaek White Alvin , Hedayati Ali , Yick Tim , Gangoli Varun Shenoy , Niu Yubiao , Lethbridge Sean , Tsampanakis Ioannis , Swan Gemma , Pointeaux Léo , Crane Abigail , Charles Rhys , Sallah-Conteh Jainaba , Anderson Andrew O , Davies Matthew Lloyd , Palmer Richard E.
Published: November 2021

For every three people on the planet there is approximately two Tonne (Te) of available plastic waste. We show that carbon recovery from polystyrene (PS) plastic is enhanced by the co-addition to solvents to grow carbon nanotubes (CNTs) by liquid injection chemical vapour deposition. Polystyrene was loaded up to 4 wt% in toluene and heated to 780 °C in the presence of a ferrocene catalyst and a hydrogen/argon carrier gas in a 1:19 ratio. High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used to identify multi-walled carbon nanotubes (MWCNTs). The PS addition in the range from 0 to 4 wt% showed improved quality and CNT homogeneity; Raman “Graphitic/Defective” (G/D) values increased from 1.9 to 2.3; mean CNT diameters increased from 43.0 to 49.2 nm; and maximum CNT yield increased from 11.3% to 14.2%. Since both the CNT diameters and the percentage yield increased with respect to polystyrene addition, we conclude that carbon from the PS contributes to the carbon within the MWCNTs. The electrical contact resistance of acid washed Bucky papers produced from each loading, ranged from 2.2 to 4.4 Ohm, with no direct correlation to PS loading. Due to this narrow range, the materials with different loading were mixed to create six wires of an Ethernet cable and tested using iPerf to give uplink and downlink speeds of ~99.5 Mbps, comparable to Cu wire of identical dimension (~99.5 Mbps). The lifecycle assessment (LCA) of CNT wire production was compared to copper wire production for the use case in a Boeing 747-400 over the lifespan of the craft. Due to their lightweight nature the CNT wires decreased the CO2 footprint by 21 kTonne (kTe) over the aircraft lifespan.
Recent Advancements in CAD/CAM Same-Day Dentistry in Practice and Education
Authors: Bencharit Sompop , Clark Wendy A , Stoner Lisa O , Chiang Gautam , Sulaiman Taiseer A.
Published: November 2021

Digital dentistry, including CAD/CAM dentistry, is perhaps the most disruptive innovation in dentistry to date. The rapid development of digital dentistry technologies over the past several decades has enabled clinicians to improve patient care by significantly reducing the time necessary for the restorative phase of treatment. Advancements in intra-oral scanning and computer-aided design and manufacturing (CAD/CAM), in conjunction with new dental CAD/CAM ceramic materials, have simplified patient care and made same-day dentistry a reality. This review aims to present the most recent advancements described in current literature as well as to document the successful implementation of digital dentistry into a predoctoral program. The overall process of CAD/CAM same-day dentistry and the accompanying advancements in software and materials were presented and discussed. Implementation of technology and personnel requirements were reviewed. CAD/CAM dentistry has been influential in shaping and improving dental practice and education, and this influence will only continue with time.
On the Potential of a Poly(Vinylidenefluoride-Co-hexafluoropropylene) Polymer Inclusion Membrane Containing Aliquat® 336 and Dibutyl Phthalate for V(V) Extraction from Sulfate Solutions
Authors: Bahrami Salar , Dolatyari Leila , Shayani-Jam Hassan , Yaftian Mohammad Reza , Kolev Spas D.
Published: November 2021

A polymer inclusion membrane (PIM) composed of 50 wt% poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) as its base polymer, 40 wt% Aliquat® 336 as its extractant and 10 wt% dibutyl phthalate (DBP) as plasticizer provided efficient extraction of vanadium(V) from its sulfate solutions adjusted to pH 2.5. It was suggested that V(V) was extracted as VO2SO4− via an anion exchange mechanism. Quantitative back-extraction was achieved in a sulfuric acid solution (6 mol L-1) containing 1 v/v% of hydrogen peroxide. It was assumed that the back-extraction process involved the oxidation of VO2+ to VO(O2)+ by hydrogen peroxide. The newly developed PIM with the optimized composition mentioned above exhibited excellent selectivity for V(V) in the presence of metallic species present in digests of spent alumina hydrodesulfurization catalysts (i.e., Al(III), Co(II), Cu(II), Fe(III), Mn(II), and Ni(II)). The co-extraction of Mo(VI) with V(V) was eliminated by its selective extraction at pH 1.1. The optimized PIM was characterized by contact angle measurements, atomic-force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA)/derivatives thermogravimetric analysis (DTGA), and the stress-strain measurements.
Stem Cell Differentiation Stage Factors (SCDSFs) Taken from Zebrafish Embryo During Organogenesis and Their Role as Epigenetics Regulators Able to Reverse Neurosensory Hearing Loss
Authors: Biava Pier Mario , Ciaurelli Stefano , Cibelli Riccardo Benzi , Pisano Gianpaolo
Published: November 2021

Hearing dysfunctions can be classified by type, degree, configuration, time of onset, aetiology, and finally, consequences on speech development. They can be divided into conductive, mixed, central types and sensorineural. Conductive hearing loss (CHL) results from interference with the mechanical transmission of sound through the external and middle ear; it can be congenital, as a consequence of anatomic abnormalities, but it can commonly be acquired following middle ear inflammatory pathologies. Sensorineural hearing loss (SNHL) results from failure to transduce vibrations to neural impulses in the cochlean and is a consequence of an irreversible damage to the differentiated cells which make up the organ of hearing and the acoustic paths at various levels. Mixed hearing loss involves a combination of these two types in the same ear. Studies in neuroscience field have shown that the prevention of cell degeneration is only possible if all the factors taken at the different stages of stem cells’ multiplication and differentiation are administered together. We have demonstrated this in a recent study on the ability of SCDSFs to prevent neurodegeneration in hippocampal cells of the CA1 zone in mice. This study confirms previous findings demonstrating that early developmental zebrafish embryo extracts could act as a modulator of senescence in human mesenchymal stem cells (hMSC) isolated from many adult tissues. These findings have open a promising way for the approaches promoting the rejuvenation and regeneration of different tissues, by-passing stem cell transplantation. In the present clinical trial we have used SCDSFs to study the possible reversion of neurosensory hearing loss, until now considered an irreversible condition.
Age, Genesis, and Seismogenic Deformations of the Vuoksa River Terraces on the Karelian Isthmus (Northwestern Russia)
Authors: Shvarev S.V. , Subetto D.A. , Zaretskaya N.E. , Molodkov A.N.
Published: November 2021

—Terraces at four hypsometric levels were studied in the Vuoksa River basin (northern part of the Karelian Isthmus, NW Russia). New data on nine sections of late Quaternary–Holocene sediments have been obtained. Their age has been determined (for the first time for surface deposits in the studied region) in the interval from 90 to 2 ka. The terrace sediments are disturbed by deformations (faults, folds, and liquefaction) caused by six strong earthquakes in that period. The relationships among the terrace levels, ages, stratigraphy, and structures of loose sediments point to their formation under the impact of differentiated tectonic motions triggered by the activation of the ancient “Vuoksa” fault zone in the late Neopleistocene and Holocene.
Subsea Well Intervention Readiness in Brazil
Authors: Purificação Rafael Augustinis , dos Santos Julia Vieira , Gonzaga Matheus Marins
Published: November 2021

The purpose of this study is to assess the subsea well intervention capabilities in Brazil from an operator point of view and how it compares to other regions in the world, in terms of equipment availability, technology and readiness. The object of this assessment will be restricted to the well access systems, given the numerous scenarios that can drive a subsea well intervention.

The intent is to identify the main challenges an International Oil Company (IOC) and/or Local Oil Company (LOC) operating in Brazil must overcome in order to keep a robust and realistic contingency plan in case of any well integrity issue. Also, similar challenges are experienced whenever production restoration is needed and/or even opportunities for production enhancement are economically assessed to viable, or not. Last but not least, well access during the last phase of a well lifecycle (plug and abandonment) is also a key element. This will be discussed further in.

Until the late 90's, the subsea oil industry in Brazil was restricted to the state-run operator and the supply chain to the business had developed itself around the mindset to maidenly supply a single state-run operator demand. After the market opening and consolidation of the IOC's and LOC's in the subsea market, a lack of local supply of several goods and services started to present itself.

Since well access systems are expensive and the base case is that you won't use it unless you have a problem, there's a strong unconscious desire not to worry about it until you really need it. Sharing the same view, service companies tend to enforce the sale of these kits to the operator, rather than focus on a rental solution. Moreover, when service companies provide rental solutions, they are not kept in country and mobilization fees and lead time become a showstopper on many cases.

In view of the scenario described above and ways of operation of the Brazilian market IOC's and LOC's a solution will be proposed to mitigate the risk of unavailability and reduce costs based on the sharing economy principles.
A New Approach to Barrier Verification
Authors: Bruce Thomas J , Stein Arild F
Published: November 2021

Objectives/Scope

Verification and testing of a wellbore barrier, in older assets has proven to be challenging. Even more so when the well has structural issues, indemnities or weak spots in the barrier envelope, that limits the possibility to get a positive pressure verification of the barrier with an applied surface pressure. The paper will air on the operational use of this novel test method and the tools used, to allow an in well verification of any type of barrier to secure the well for a repair or a upcoming P/A operation. A pilot job case history will be included to illustrate use of the principles.

Methods, Procedures, Process

Find a suitable location with necessary support and strength in the well. If installing a mechanical barrier by means of a bridge plug as the primary barrier, we will monitor the installation forces in the anchoring and sealing sequence. This individual signature will be verified towards a nominal base line signature towards a library of thousands of collected installation profiles. Any abnormality can trigger a release and possible relocating of the barrier. A second verification barrier will then be installed above the primary barrier. When both installation signatures are accounted for, we can pressure test the installed barriers. This is done with a pressure inflow tool, where we introduce a calculated predetermined pressure drop between the installed primary barrier and the verification barrier. By monitoring this pressure alteration vs. the pressure above the verification barrier, we can determine if we have a verified barrier.

Results, Observations, Conclusions

We now have the Primary Barrier verified in the direction of flow (negative pressure test). And verification barrier as the secondary barrier (verified with a positive pressure test). If a dual barrier is requested, you can leave the verification barrier as secondary barrier.

Novel/Additional Information

Pressure manipulation is done with existing and proven technology and is re-usable after re-setting at surface. By monitoring this pressure alteration, we can verify the installed primary and verification barrier in one run. This without any time-consuming pressure manipulating from surface.
Late Life Field Management with Instrumentation Failure. Modelling Predictions and Successful Validations of Late Life Subsea Gas Condensate System Using Historical Field Data
Authors: Lau Lawrence Khin Leong , An Kun , Tong Wu Jun , Wang Song , Yue Zhi Wei , Duan Jiang Nan
Published: November 2021

Depleting reservoir pressure, increasing water cut and decreasing overall system production leading to increased liquid holdup are among the key challenges for typical late life gas condensate production system. This paper elucidates modelling details of a late life offshore subsea gas condensate system and how the findings are implemented and validated with actual field data for successful outcomes.

There is only one subsea well remain in operation with relatively long subsea flowlines. Subsea pressure and temperature transducers are out of service as the asset approaches the end of design life. In this context, flow assurance team has taken the modelling approach in order to minimize cost and to maximize values. Detailed transient multiphase thermohydraulics models are developed and benchmarked against field data. Historical field data over the past two years are utilized in order to predict the trend for key parameters such as well production rates and water to gas ratio (WGR).

Matrix of simulation including the predictions of slugging flow regimes are carried out for the entire flow path, from reservoir characteristics descriptions at bottom hole, through flow regimes analysis at topsides slug catcher. Three categories of operation characteristics, namely the low risk, medium risk, and high risk production periods are identified. It is predicted that the system would start to fall into slugging flow regimes from 2 months onwards with final production end date of after 10 months. This is shared with wider team such that operations and base management teams are informed with predicted multiphase flow characteristics for the remaining production life. As such, gas supply succession plan can be executed in time to ensure uninterrupted downstream commercial agreement. Feedbacks from operations team revealed accurate predictions of such analysis, including slugging flow phenomenon which was associated with flow and pressure fluctuations, was observed in field as predicted by the study. More importantly, the production cut-off date is accurately predicted 10 months ahead and within the accuracy of ± 1 week.

This study demonstrated how historical field data, coupled with detailed transient multiphase thermohydraulics modelling, can be utilized for offshore gas condensate production predictions during late life. Without transducers and/or virtual metering data feed, production end date can be accurately predicted based on key parameters analysis. This is particularly valuable for supply succession planning and is deemed a successful case study with significant positive outcomes which can be used as reference for other gas condensate assets.
Managing the Salvage, Removal, Preservation and Re-Installation of Tilted Wellhead Platform
Authors: Zainal Abidin Suzaini
Published: November 2021

This paper describes the planning, offshore execution and technology involved in the intact salvage, removal, preservation and relocation of a Wellhead Drilling Platform (WHP) which was tilted during drilling operation in the "X" field.

The field development plan consists of a WHP tied-back to a Floating, Production, Storage & Offloading (FPSO), anchored at 700 m away from the WHP. The oil field is located 110 km from shore and at water depth of 57 m. The Project Management Team (PMT) had completed the installation of the WHP, unfortunately mishap was happened when the WHP experienced tilting during drilling operation. The platform tilted/leaned two (2) degrees towards the drilling rig.

The strategy adopted by the PMT was to rig-down and move out the affected rig; immediately salvage the newly installed 1,300MT WHP's topside. The work was executed under the crisis management envelop with the aim to save the rig and platform from total loss i.e., to avoid the platform topples into the sea and subsequently hits the rig.

The salvage operation employed unique processes, procedures, and technology to safe hold the tilted platform by Anchor Handling Tugs (AHTs) and pipelay barge; rig-down and move out the drilling rig, reinstatement of lifting lug/pad eyes which had previously removed after completion of topside installation and finally removal of topside from the tilted jacket. The topside then transported to the fabrication yard, where there the topside had been preserved on the transportation barge for a period of five (5) months while waiting for the new jacket to be fabricated and installed. The re-development of the affected offshore facilities from the incident involved installation of new jacket at 150 m away from the tilted jacket location, re-installation of the topside to the new installed four (4) legged jacket, re-routing the previous installed infield pipelines (8" Liquid, 16" Wet Gas and 12’ Export Gas pipeline from FPSO) and tied-in to the new platform. The planning, innovation and execution has resulted in a significant cost containment and managed to avoid major disaster; subsequently safeguard Company's reputation. The salvage of the topside and rejuvenation of the pipelines have managed to avoid the reconstruction of the topside module which potentially could lead to non-cost recovery of huge amount of additional cost (in USD millions) and managed to avoid any Loss of Primary Containment (LOPC) by taken all the necessary precautions.
Advances in Abandonment and Disposal Technology of Aging Oil and Gas Pipelines
Authors: Jing Jiaqiang , Wang Wenlu , Wu Dongrong , Luo Jinhua , Zeng Shuang , Zheng Tianlun , Chen Hongkun
Published: November 2021

When the operation benefit of an oil and gas pipeline is not enough to cover its operation cost, and the pipeline is no alternative use, seriously damaged, aged or the operation risk exceeds the acceptable range, it is bound to cause serious safety and environmental hazards along the pipeline, especially for the over age pipeline in service, therefore its scientific abandonment and reasonable disposal is particularly important and urgent.

Focused on the methods for judging abandonment, retirement modes, cleaning and environmental management of oil and gas pipelines, the characteristics of existing methods for predicting the remaining life of the pipelines and their application in abandonment and disposal are compared and analyzed, and the basis and adaptability of oil and gas pipelines retirement are illuminated. According to the actual situation and environment of the discarded pipelines, the selection basis and applicable conditions of the pipeline and facility disposal methods such as demolition, in-situ shelving and their combination are expounded.

It is found that North America has rich experience and mature technology in oil and gas pipeline abandonment and disposal, but many countries, including China, seriously lack scientific and systematic evaluation standards, practical experience, related theoretical and technical investigations. This study has important reference and practical significance for promoting the development of abandonment and disposal technology of an aging oil and gas pipeline, and ensuring the personal safety and ecological environmental protection along the abandoned pipeline.

This paper presents the status quo of over age service and abandonment decision-making of oil and gas pipelines in the world, draws lessons from the experience of safety and environmental protection disposal of the global abandoned pipelines, and puts forward the principle and method of abandonment judgment and scientific disposal of the aging pipelines based on residual life evaluation. This method has sufficient basis, strong adaptability and wide application.
Subsea Gas Well Late Life Restart Lesson Learned: Failure Analysis and Operating Strategy
Authors: Wang Song , Lau Lawrence Khin Leong , Tong Wu Jun , An Kun , Duan Jiang Nan , Wang Xing
Published: November 2021

This paper elucidates the importance of flow assurance transient multiphase modelling to ensure uninterrupted late life productions. This is discussed in details through the case study of shut-in and restart scenarios of a subsea gas well (namely Well A) located in South China Sea region. There were two wells (Well A and Well B) producing steadily prior to asset shut-in, as a requirement for subsea pipeline maintenance works. However, it was found that Well A failed to restart while Well B successfully resumed production after the pipeline maintenance works. Flow assurance team is called in order to understand the root cause of the failed re-start of Well A to avoid similar failure for Well B and other wells in this region.

Through failure analysis of Well A, key root cause is identified and associated operating strategy is proposed for use for Well B, which is producing through the same subsea infrastructure. Transient multiphase flow assurance model including subsea Well A, subsea Well B, associated spools, subsea pipeline and subsea riser is developed and fully benchmarked against field data to ensure realistic thermohydraulics representations of the actual asset. Simulation result shows failed restart of Well A and successful restart of Well B, which fully matched with field observations.

Further analysis reveals that liquid column accumulated within the wellbore of Well A associates with extra hydrostatic head which caused failed well restart. Through a series of sensitivity analysis, the possibility of successful Well A restart is investigated by manipulating topsides back pressure settings and production flowrates prior to shut-in. These serve as a methodology to systematically analyze such transient scenario and to provide basis for field operating strategy.

The analysis and strategy proposed through detailed modelling and simulation serves as valuable guidance for Well B, should shut-in and restart operation is required. This study shows the importance of modelling prior to late life field operations, in order to avoid similar failed well restart, which causes significant production and financial impacts.
Laboratory virulence of entomopathogenic nematodes to the sweetpotato whitefly, Bemisia tabaci
Authors: Li Yinping , Mbata George N. , Shapiro-Ilan David I.
Published: November 2021

The sweetpotato whitefly, Bemisia tabaci Middle East-Asia Minor 1 (MEAM1), is a major insect pest on vegetable crops worldwide. Enormous economic losses result from direct and indirect plant damage caused by MEAM1. Biological control using entomopathogenic nematodes (EPN) may be an effective alternative strategy against MEAM1 because this pest has developed resistance to most insecticides. First, nine EPN species (Heterorhabditis bacteriophora, H. indica, H. georgiana, H. floridensis, Steinernema feltiae, S. carpocapsae, S. riobrave, S. glaseri, and S. rarum) were investigated for virulence to MEAM1 third instar nymphs on snap bean leaves under laboratory conditions. The mortality of MEAM1 nymphs was evaluated at 3 days post-inoculation (dpi). Compared to the water control, the application of the nine EPN species except S. glaseri resulted in significantly higher mortality of MEAM1 nymphs, such as H. bacteriophora (66.31%), H. floridensis (56.38%), S. carpocapsae (54.54%), and S. rarum (57.80%). Subsequently, the four virulent EPN species, H. bacteriophora, H. floridensis, S. carpocapsae, and S. rarum were evaluated further for virulence to MEAM1 nymphs on snap bean and tomato leaves. The mortality of MEAM1 nymphs was assessed at 3 dpi and 7 dpi. There were no significant differences in MEAM1 nymphal mortality between tomato and snap bean at either 3 dpi or 7 dpi. The mortality of MEAM1 nymphs caused by the application of H. floridensis (99.25%) was significantly higher than the other three EPN species and the water control at 7dpi. The results indicate that H. floridensis is a very promising biocontrol agent for B. tabaci management.
Segurança cibernética em Moçambique
Authors: Chaves Cepik Marco Aurélio , Marcelino Henriques Manuel
Published: November 2021

Em 2018, Moçambique tornou-se signatário da Convenção da União Africana sobre Segurança Cibernética e Proteção de Dados Pessoais. O país participa também da União Internacional de Telecomunicações (ITU) e da Comunidade de Desenvolvimento da África Austral (SADC). Processos de securitização do ciberespaço em Moçambique constituem um mecanismo social que produz consequências materiais. Este artigo busca contribuir para a compreensão dos desafios de segurança cibernética de duas formas. Primeiro, explicitando conceitos como ciberespaço, internet, infraestrutura, segurança e defesa no âmbito digital. Segundo, propondo um modelo de maturidade adaptado para monitorar e avaliar o desenvolvimento da segurança cibernética em Moçambique.
The vibration response of transformer windings under harmonic excitations and its applications
Authors: Xin Qian , Yin Hui , Zhou Feiyan , Wang Shizhe , Hong Kaixing , Xu Suan
Published: November 2021

The power transformer is a key device in the power grid systems. The mechanical degradation of windings represented by the clamping force looseness will cause the decline of the short circuit withstand ability, and cause further damages. This paper proposes a clamping force diagnosis method for operating windings based on the study of the vibration response. In the theory part, the influence of the load current on the natural frequency of windings is discussed, and the influence of the natural frequency change on the steady-state vibration response is studied to obtain the vibration feature related with the clamping force. The subspace method is used to fuse two vibration sequences with the same characteristics to eliminate the measurement error. In the experiment, the free vibration test was performed on a short circuit on-load winding structure. It was proved that the natural frequency change can be extracted from the relationship between the amplitude change of the 100 Hz component and the current change. In the field tests, the vibration sequences of two typical transformers were compared, and the results show that the vibration feature extracted from the relationship between the amplitude variation and the current change contains the structural information of windings.
Development of a method for noise suppression of a signal from pressure sensors on main gas pipelines using wavelet transformation
Authors: Darsalia Nana , Kitaev Sergey , Muratova Vera , Farukhshina Regina
Published: November 2021

Natural gas produced in the Russian Federation is transported through main gas pipelines united into the Unified Gas Supply System of the Russian Federation. The system of main gas pipelines - the most important link in the unified gas supply system – is a large, complex and continuously developing technological system. Maximum internal pressure is one of the key characteristics for any pipeline. This indicator helps to set the limit for the capacity of the pipeline (maximum volume of pumped gas per unit of time), its level of reliability, as well as the level of hazard and potential risk (the higher the pressure inside the pipeline, the more potential threat it carries). In order to increase the reliability of determining the pressure in the gas pipeline, it is proposed to perform noise suppression using a wavelet transform in the work. Noise reduction in the wavelet transform is carried out due to the fact that the signal is decomposed into approximating and detailing coefficients. After removing the detailing component, the decomposition is restored and the output is a slightly distorted signal. Thus, when you remove an insignificant part of the original signal, the graphs of the change in values become more visual. This paper compares the efficiency of wavelet based thresholding techniques in the presence of noise for various wavelet family. For comparison, the trend processing was performed by two types of wavelets recommended for noise reduction - Symlet and Daubechies wavelets.
Geomorfologia da Serra do Feiticeiro em Lajes/RN
Authors: Bezerra Gleydson Rubens de Farias
Published: November 2021

Os compartimentos geomorfológicos da Superfície Sertaneja do Rio Grande do Norte são o resultado da conjugação de diversos processos que remontam a fusão e divisão de paleocontinentes, deformações estruturais e processos de pediplanação marcadamente a partir do Paleógeno. No município de Lajes/RN, relevos de modesta altitude interrompem a planura suave da Superfície Sertaneja, constituindo-se em elementos importantes para a compreensão da evolução geomorfológica potiguar, destacando entre eles o Pico do Cabugi, como registro do mais jovem evento magmático na porção continental do Brasil e a Serra do Feiticeiro. Assim, o objetivo geral deste trabalho é discutir a geomorfologia da Serra do Feiticeiro e sua importância na dinâmica ambiental de Lajes. A metodologia é baseada em revisão da literatura científica, trabalhos de campo e aplicação de geoprocessamento. Os resultados apontam que a Serra do Feiticeiro é um maciço estrutural originado pela fissão e junção de paleocontinentes. A evolução ulterior sugere que suas escarpas foram fortemente afetadas por falhamentos e erosão diferencial. A hidrografia de Lajes é fortemente influenciada pela existência desse relevo que é um importante divisor de bacias hidrográficas.
Atividades Econômicas e Fisionomia das Vertentes no Maciço Residual de Uruburetama, Ceará, Brasil.
Authors: Nascimento Neto José Nelson do
Published: November 2021

Este trabalho é um ensaio do projeto de mestrado acadêmico em Geografia da Universidade Estadual Vale do Acaraú-UVA. Objetivamos contribuir no planejamento ambiental do maciço residual de Uruburetama, no Ceará. Vincula que o relevo em questão proporcionou o processo de ocupação desencadeado por meio das cidades situada no maciço em questão associando a modificação de sua fisionomia por meio dos setores primário, secundário e terciários ao qual referenciamos refletir essa relação em um registro espaço-temporal. A metodologia consiste de uma revisão bibliográfica, atividades de campo, registro fotográfico e na elaboração do material cartográfico por meio do programa Qgis. Os resultados compreende a dinâmica dos setores econômicos que molda a fisionomia do relevo atento a essa realidade apresentamos como proposição uma elaboração de ações intervencionista que possam contribua no planejamento ambiental da área. Consideramos que o setor primário influência significativamente a fisionômica das vertentes sendo oportuno desenvolver um planejamento ambiental.