bluuebunny/crossref_metadata_2025 huggingface dataset:
Detecting Emotion in Indonesian Tweets: A Term-Weighting Scheme Study
Authors: Nugroho Kuncahyo Setyo , Bachtiar Fitra A. , Mahmudy Wayan Firdaus
Published: May 2022

Background: Term-weighting plays a key role in detecting emotion in texts. Studies in term-weighting schemes aim to improve short text classification by distinguishing terms accurately.
Objective: This study aims to formulate the best term-weighting schemes and discover the relationship between n-gram combinations and different classification algorithms in detecting emotion in Twitter texts.
Methods: The data used was the Indonesian Twitter Emotion Dataset, with features generated through different n-gram combinations. Two approaches assign weights to the features. Tests were carried out using ten-fold cross-validation on three classification algorithms. The performance of the model was measured using accuracy and F1 score.
Results: The term-weighting schemes with the highest performance are Term Frequency-Inverse Category Frequency (TF-ICF) and Term Frequency-Relevance Frequency (TF-RF). The scheme with a supervised approach performed better than the unsupervised one. However, we did not find a consistent advantage as some of the experiments found that Term Frequency-Inverse Document Frequency (TF-IDF) also performed exceptionally well. The traditional TF-IDF method remains worth considering as a term-weighting scheme.
Conclusion: This study provides recommendations for emotion detection in texts. Future studies can benefit from dealing with imbalances in the dataset to provide better performance.
Keywords: Emotion Detection, Feature Engineering, Term-Weighting, Text Mining
The Drivers of a Digital Signature System Adoption: Evidence from Finance and Information System Departments
Authors: Santosa Ahmad Arif , Alamsjah Firdaus
Published: May 2022

Background: With the massive e-commerce transactions and document transfers, reliable system protection is needed. A digital signature is a tool that consists of encryption and decryption algorithms in a secret key to prevent data theft and online fraud.
Objective: This research proposes an integrated technology-organization-environment (TOE) and the unified theory of acceptance and use of technology (UTAUT) to determine the factors affecting consumer intention to adopt the digital signature system. This research uses finance and information system departments’ perspectives in various industries.
Methods: The analytical method is the Structural Equation Modeling (SEM) approach using the Smart Partial Least Square statistical version 3.0 software to examine the hypothesized connections between latent variables.
Results: The results show that support from top management, size of the enterprise, and social influence have significant and positive effects on digital signature adoption. Meanwhile, user involvement and perceived simplicity have a negative effect on the adoption of a digital signature system in finance and information system departments.
Conclusion: The current research suggests that executive levels in the finance and information system departments encourage the adoption of digital signature tools in doing daily tasks to increase efficiency.
Keywords: Digital signature, consumer intention, finance and information system, structural equation modeling, TOE and UTAUT
Academic Recommender System Using Engagement Advising and Backward Chaining Model
Authors: Fiarni Cut , Gunawan Arif Samuel , Victor Fredrick
Published: May 2022

Background: The goal of academic supervision is to help students plan their academic journey and graduate on time. An intelligent support system is needed to spot potentially struggling students and identify the issues as early as possible.
Objective: This study aims to develop an academic advising recommender system that improves decision-making through system utility, ease of use, and clearly visualized information. The study also aims to find the best advising relationship model to be implemented in the proposed system.
Methods: The system was modeled by following the hybrid approach to obtain information and suggest recommended actions. The recommendation was modeled by backward chaining to prevent students from dropping out.
Results: To validate the recommendations given by the proposed system, we used conformity level, and the result was 94.45%. To evaluate the utility of the system, we used the backbox method, resulting in satisfactory responses. Lastly, to evaluate user acceptance, we used the technology acceptance model (TAM), resulting in 85% ease of use and 91.2% perceived usefulness for the four main features, study planning, graduate timeline simulation, progress report, and visualization of academic KPIs.
Conclusion: We propose an academic recommender system with KPIs visualization and academic planning information.
Keywords: Academic advising model, recommender system, backward chaining, goal-driven, technology acceptance model, certainty factor
Potensi Penerapan Urban Mining dari E-Waste Berbasis Ekonomi Sirkular dalam Pembangunan Berkelanjutan di Bukittinggi
Authors: Ilham Ilham , Ginting Sutradara , Ritonga Sintiya Hamdina , Aslam Izzan Nur
Published: May 2022

E-waste, atau electronic waste, merupakan limbah listrik dan elektronik yang berupa kabel listrik, laptop, dan lain-lain. Smartphone merupakan salah satu alat elektronik yang memiliki banyak manfaat bagi manusia. Perkembangan yang pesat menyebabkan setiap tahunnya e-waste dari smartphone mengalami peningkatan di Indonesia terutama sekali di Bukittinggi. Karena setiap tahunnya mengalami peningkatan, penanggulangan e-waste mejadi sangat penting bagi lingkungan dan telah menjadi kewajiban bagi beberapa negara di dunia. Ekonomi sirkular merupakan salah pilihan yang tepat dengan konsep penggunaan kembali dan daur ulang produk. Hal ini berdampak pada berkurangnya permintaan bahan baku, menurunya konsumsi sumber daya alam, dan terciptanya lapangan pekerjaan yang baru. Urban mining dengan pemanfaatan e-waste berbasis ekonomi sirkular dapat menjadi salah satu solusi, terutama dalam mengganti proses pertambangan konvensional yang cenderung merusak lingkungan dengan menjadi alternatif penghasil komoditas pertambangan konvensional. Penelitian ini menggunakan metode Material Flow Analysis (MFA). Data penggunaan smartphone diperoleh dari Badan Pusat Statistik (BPS) Bukittinggi selama sepuluh tahun ke belakang. Hasil penelitian ini selanjutnya menjadi bahan pertimbangan bagi sektor perekonomian dan lingkungan.
Evaluasi pembongkaran overburden berdasarkan target produksi bulanan di PT Bhima Sakti Bersaudara
Authors: Yuda Eka Sandi Prakasa , Triantoro Agus , Saismana Uyu
Published: May 2022

Aktifitas penambangan biasanya diawali dengan pengupasan lapisan tanah penutup yang menggunakan peralatan mekanis. Agar kegiatan tersebut mencapai hasil yang optimal maka dilakukan perencanaan. Tahapan perencanaan tambang dilakukan untuk menjamin operasi penambangan yang akan dilakukan terkoordinasi dan sesuai dengan target yang direncanakan karena apabila target pengupasan lapisan tanah penutup tidak tercapai maka target produksi bahan galian berharga dalam hal ini batubara juga tidak tercapai.Penelitian ini dilakukan dengan mengumpulakn data primer dan data sekunder menggunakan dua cara, yaitu pengamatan lapangan secara langsung dan penggunaan data perusahaan. Proses pemecahan masalah  menggunakan metode komputasi dan analisis disertai data-data berupa pete, gambar, grafik dan tabel yang dapat membantu dalam penyampaian informasi hasil penelitian.Berdasarkan dari hasil pengambilan data dilapangan, maka didapatkan rata-rata cycle time alat gali muat excavator sany 365 H sebesar 19,82 detik, kemudian rata-rata cycle time alat angkut hino 500 didapatkan sebesar 4,49 menit. Berdasarkan  tingkat ketercapaian antara target produktivitas dengan aktual, rata-rata produktivitas dengan tingkat ketercapaian alat gali muat sany 365 H sebesar 162,98 bcm/jam dengan ketercapaian 95 %. Tingkat ketercapain antara target produktivitas dengan aktual, rata-rata produktivitas dengan tingkat ketercapaian alat angkut Hino 500 sebesar 55,87 bcm/jam dengan ketercapaian sebesar 65 %. Berdasarkan hasil perhitungan match factor dengan menggunakan data aktual didapatkan hasil match factor 0,89 dengan menggunakan 2 alat angkut, kemudian hasil perhitungan simulasi match factor dengan menggunakan 3 alat angkut didapatkan hasil match factor sebesar 1,34.
Pengaruh nilai UCS dan GSI dalam menentukan faktor keamanan lereng batuan
Authors: Maharza Calvin , Koesnaryo S. , Nugraha Arief Pambudi , Simarmata Bestian P.
Published: May 2022

Kawasan waduk sermo memiliki beberapa akses wisata yang cukup baik sehingga memungkinkan untuk warga sekitar mengunjungi tempat tersebut. Untuk menambah kenyamanan para wisatawan maka diperlukan kajian mengenai kestabilan lereng di Kawasan tersebut. Variasi dari nilai parameter sifat mekanik batuan yaitu nilai Uniaxial Compressive Strength (UCS) dan nilai Geological Strength Index (GSI) akan mempengaruhi perhitungan faktor keamanan suatu lereng sehingga perlu diteliti seberapa besar pengaruh dari masing-masing nilai tersebut. Lereng pada Kawasan Waduk Sermo memiliki klasifikasi GSI untuk massa batuan adalah berkisar antara 65-85 dan memiliki nilai UCS berkisar antara 50-100. Kemudian nilai tersebut disimulasikan ke dalam perhitungan kestabilan lereng dengan metode Bishop dalam Limit Equilibrium Method, didapatkan faktor keamanan lereng pesimis ialah 9.51. Hubungan nilai GSI terhadap Faktor Keamanan lereng adalah positif, semakin besar nilai GSI maka semakin Besar pula nilai FK pada suatu lereng. Hubungan nilai UCS terhadap Faktor Keamanan lereng adalah positif, semakin besar nilai GSI maka semakin Besar pula nilai FK pada suatu lereng. Pengaruh nilai UCS terhadap Faktor Keamanan lereng lebih stabil dibandingkan nilai GSI dengan kenaikan 1.42 nilai FK setiap kenaikan 10 nilai UCS.
CTRI requirement of prospective trial registration: Not always consistent
Authors: Chakraborty Indraneel , Saberwal Gayatri
Published: May 2022

In a clinical trial registry, one determines whether a trial is registered prospectively or retrospectively by comparing the date of registration with the date on which enrollment started. However, in Clinical Trials Registry – India (CTRI), in addition, the top of each record is labelled with the phrase “Trial Registered Prospectively” or “Trial Registered Retrospectively”. In examining CTRI records, we have found that (a) although retrospective registration has been disallowed from April 1, 2018, some trials were registered retrospectively; (b) in some cases, enrollment started after registration, even though they were labelled “Trial Registered Retrospectively”, which is misleading; and (c) in some cases, the date of first enrollment was modified, changing a retrospective registration to a prospective one, although the label “Trial Registered Retrospectively” persisted. This, too, is misleading. The CTRI administration should take suitable steps to prevent late registration and mislabelling of trials regarding their registration status.
“Some of them are afraid of the language”: Perceptions of TVET college staff about the relationship between English language proficiency and academic performance among Engineering students
Authors: Stander L. , Du Plooy B. , Scheckle E.
Published: May 2022

Despite the fact that Technical and Vocational Education and Training (TVET) colleges are seen as instrumental in addressing South Africa’s labour market skills shortages and high youth unemployment rate, the extremely low throughput and certification rates at these institutions prevent colleges from achieving this goal. The vast majority of students enrolled at TVET colleges come from lower socioeconomic backgrounds and speak English as a second or additional language, yet English is the language through which teaching is conducted at all South African TVET colleges. Prior research has shown that there is a definite relationship between poor academic performance (AP) and learning in an additional language. Existing research of this nature has focused on schools and universities, but there is a dearth of research about the relationship between AP and English Language Proficiency (ELP) in the TVET sector. In order to address this gap, a mixed method study was conducted at one Eastern Cape TVET College to investigate whether the poor AP of National Vocational Certificate (NC (V)) Level 2 Engineering students can be related to their ELP. The initial quantitative phase of the study confirmed prior research by showing that NC (V) students’ ELP is indeed significantly associated with their throughput rate and their performance in each specific subject. This article reports in particular on the second qualitative phase of the study, which was based on interviews with TVET college staff involved in teaching Engineering students. The most significant finding is that teaching staff, who daily work at the proverbial coal face of TVET training, are from their practical experience, very well aware of the fact that there is a crucial link between the ELP and AP of their students, that they employ a variety of strategies to address associated problems, but that they feel these are often insufficient and ineffective in the face of students trying to learn in a second language. This study extends the research about the role of language as a cognitive tool in learning in the Engineering disciplines. It also provides an opportunity to rethink the hegemonic, normalised position of English in Engineering studies and consider possibilities to mobilise indigenous languages as resources for epistemological access in higher education.
Trends of Treatment Development in Rheumatoid Arthritis: Promise, Progress, and Challenges
Authors: Jiang Ping , Wei Kai , Zhao Jianan , Jin Yehua , Chang Cen , Zhang Runrun , Xu Lingxia , Xu Linshuai , Shi Yiming , Guo Shicheng , Schrodi Steven J , He Dongyi
Published: May 2022

Rheumatoid arthritis (RA) is a chronic, systemic, abnormal inflammatory immune response. It is characterized by the involvement of the synovium and multiple organs and the destruction of joints and articular cartilage. Over the past 30 years, several promising novel compounds and antibodies have been developed for the treatment of RA. The introduction of new drugs and precision medicine for all forms of RA raises several issues related to access to novel treatments by patients, optimal regimen selection, cost-effectiveness, prognosis monitoring and outcome surveillance, particularly with regarding to the development of low drug response rates, drug resistance and adverse side effects. Tremendous attention has been given to the identification of optimized drug combinations for the treatment of RA, particularly in early high-risk vulnerable and early individuals. Addressing these issues requires novel therapeutic approaches with new mechanisms and the establishment of accurate guidelines for drug selection, drug recombination, and non-chemical therapeutic efforts. In this study, we reviewed the most exciting recently established or ongoing novel drugs and methods according to the clinical trial database maintained by the United States National Library of Medicine and discussed the trends in RA drug development and challenges in the treatment, providing a reference significant for the accurate treatment of RA and the research direction in the future.
Overexpression of a Membrane Transport System MSMEG_1381 and MSMEG_1382 Confers Multidrug Resistance in Mycobacterium smegmatis
Authors: S. Salini , Muralikrishnan Balaji , Bhat Sinchana , Ghate Sudeep , Rao Shyama Prasad , Ajay Kumar R. , Kurthkoti Krishna
Published: May 2022

Mycobacterium tuberculosis is a leading cause of human mortality worldwide and the emergence of drug-resistantstrains, demands the discovery of new classes of antimycobacterials that can be employed in the therapeutic pipeline. Previously, a secondary metabolite Chrysomycin A, isolated from Streptomyces sp. OA161 was shown to have potent bactericidal activity against drug-resistant clinical isolates of M. tuberculosis and different species of mycobacteria. The antibiotic inhibits the mycobacterial topoisomerase I and DNA gyrase leading to bacterial death, but the mechanisms that could cause resistance are currently unknown. To further understand the resistance mechanism, spontaneous resistance mutants were isolated and subjected to whole-genome sequencing. Mutation in a TetR family transcriptional regulator MSMEG_1380 was identified in the resistant isolates and was close to an operon encoding membrane protein MSMEG_1381 and MSMEG_1382. Sequence analysis and modeling studies indicated that they are components of the Mmp family of efflux pumps and over-expression of either the operon or individual genes conferred resistance to chrysomycin A, isoniazid, and ethambutol that are in TB therapy. Our study highlights the role of membrane transporter proteins in conferring multiple drug resistance and the utility of recombinant strains overexpressing membrane transporters in the drug screening pipeline.
Unlocking the Molecular and Biochemical Machinery of Insect Herbivore Resistance: the Key is a Perception of Herbivore-Associated Elicitors
Authors: Malook Saiful , Maqbool Saiqa , Hafeez Muhammad , Karunarathna Samantha Chandranath , Suwannarach Nakarin
Published: May 2022

Insect herbivores have a wide range of life cycles and feeding habits, making them extremely diverse. With their host plants, they form close relationships and suppress their defense mecha-nisms. Molecular elicitors are the key bio-elements in detection and recognition of attacking enemies in tissue consumption. Insect oral secretion, frass, and fluid of egg deposition contain bio-logical active molecules called herbivore-associated elicitors (HAEs) are recognized by pattern recognition receptors (PRRs). However, in insect herbivores, little is known about the molecular basis of signal transduction and regulation of plant resistance. Many plants distinguish insect feeding from wounding by HAEs presenting in their oral secretions (OS) and induce local and systemic responses against arthropod feeding. PRRs perceive HAEs in the oral secretion of cater-pillars in a species-specific manner to elicit exclusive defense responses. HAEs-PRRs interactions induce plant resistance by reprogramming plant metabolism and transcriptional machinery. Quantitative, timely, and coordinated plant response initiate early signalling events including Ca+2, reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs). We have discussed how early signalling cascades converge into the accumulation of phytohormones that regulate down-stream special metabolites against herbivores. In this review, we have drawn a hypothetical model of PPRs-HAEs mediated induced responses in plants and discussed how PRRs-HAEs interactions based on molecular mechanism that elicit short- and long-term induced defenses in plants. The identification of plant target insect herbivore PRRs-HAEs interactions will help to explore the fundamental molecular mechanisms of host manipulation and may generate prospects to develop novel pest resistance strategies.
Kommunikációs jellemzők tizenévesek kötött témájú képleírásában
Authors: Laczkó Mária
Published: May 2022

A magyar nyelvű diákok kommunikációjáról nemcsak tapasztalati alapon, de kísérleti úton is sok mindent lehet már tudni. A jelen vizsgálat újszerűségét az adja, hogy egy speciális kommunikációs helyzetben, az idegen nyelvi érettségi vizsga feladattípusának megfelelő beszédszituációban méri fel a diákok kommunikációjának jellegzetességeit. A tanulmány így a képi stimulusú, félreproduktív szövegalkotás sajátosságait elemzi szegmentális szinten, középiskolások körében. A kapott eredmények rámutatnak arra, hogy a közoktatásban, még a középiskolában is szükség van a szóbeli kommunikáció tervszerű, tudatos alakítására részben az anyanyelvi kommunikációs kompetencia, részben az idegen nyelvi kommunikációs kompetencia fejlesztéséhez.
A beszédhanghibákkal rendelkező diákok értékelése a köznevelésben
Authors: Kaposvári Boglárka , Mrázik István
Published: May 2022

Vizsgálatunk célja az volt, hogy a középiskolákban tanító pedagógusok attitűdjét vizsgáljuk a beszédhanghibákkal rendelkező diákokkal kapcsolatban. Az áttekintett attitűdvizsgálatok azt mutatták, hogy a sztenderdtől eltérő beszédmód válthat ki negatív értékítéletet (Bodnár 2019 és Jankovics 2016). Megvizsgáltuk, hogy mutatkozik-e eltérés a beszédhanghibát mutató beszélő és a sztenderd beszélő megítélésében, illetve a jegyalapú értékelésben. Kérdőíves vizsgálatot végeztünk, a kitöltőknek 4 hangfelvételt kellett meghallgatniuk 3 beszélőtől, közülük egy személy két különböző beszédmódban olvasta fel a szöveget (sztenderd és rotacizmus). Az eredmények azt mutatták, hogy összességében kis eltéréseket láthatunk az ügynök két felvétele közötti értékelésben. Intézménytípusonként és tantárgytípusonként vizsgálva az adatokat azonban kirajzolódik, hogy a rotacizmust mutató beszélő többször rosszabb eredményeket kapott, mint a sztenderd beszélő. A szóbeli feleletek esetében a kitöltők számára általánosságban fontos szempont volt az értékelésben a lexikális tudás. A beszéd ennek fontos közvetítője, ezért annak zavara befolyásolhatja a pedagógusok értékelését.
A tanulói beszédidő növelése az online tanórán
Authors: Gonda Zsuzsa
Published: May 2022

Az osztálytermi diskurzust vizsgáló kutatások már számos alkalommal bizonyították, hogy a tanórán a tanulói megszólalások gyakorisága és minősége nagymértékben függ az alkalmazott munkaformáktól és módszerektől. Kérdés azonban, hogy hogyan befolyásolta az online tanulási-tanítási környezet a tanórai tanulói beszéd jellemzőit. A pandémia időszaka alatt bevezetett digitális oktatást vizsgáló hazai és nemzetközi kutatások szerint a tanulói élőbeszéd a technikai korlátok és a módszertani megoldások hiánya miatt még inkább háttérbe szorult. A tanulmány egyik célja, hogy az online tanóra kommunikációs jellemzőit – ezen belül is a tanulói beszéd sajátosságait – összegezze egy hazai interjús kutatás alapján, amelyben 40 magyar nyelv és irodalom szakos pedagógus vett részt. A tanulmány további célja olyan pedagógiai-módszertani stratégiák és technikák bemutatása, amelyek segítségével a tanulói beszédidő az online térben is motiváló, strukturált és fejlesztő hatású lehet.
Szerencsegyökér. Berniczky Éva novellájának retorikai elemzése
Authors: Gulyás Márk
Published: May 2022

A Szerencsegyökér című novella Berniczky Éva fiatal kárpátaljai szerző legutolsó, összefoglaló jellegű novelláskötetének címadó darabja. Elemzése a retorika rendszerét és terminológiáját követve valósult meg. Első lépése a retorikai szituáció, azaz a megoldandó probléma vizsgálata, majd a novella típusának a megállapítása következik: a modern novellatípusok körébe illeszkedő, szimbolikus-balladisztikus novella. Ezután történik meg a novella bonyolult, párhuzamos és belső mesét is tartalmazó szerkezetének a feltárása (a belső mese is párhuzamos szerkezetű). Érvelése végig ellentétekre és ellentmondásokra épül, ezért izgalmas; az arisztotelészi enthüméma logikájával is lehet találkozni benne. Sajátos a stílusa: nincsenek benne párbeszédek, de a függő beszéd is jellemzi a szereplőket. Stílusára jellemző az allúzió és a szimbólum – maga a cím is szimbólum –, metaforái, komplex képei jellegzetesek, felfejtésük számos összefüggésre világít rá. A novella hátterében egyúttal feltárul egy szomorú, tragikus emberi sors.
Large Scale Pipe Flow Experiments for the Evaluation of Non-Chemical Solutions for Calcium Carbonate Scaling Inhibition and Control
Authors: Loureiro Juliana B. R. , Gonçalves Adão S. , Souza Breno G. B. , Pepe Iuri M. , Demetino Geydison G. , Soares Junior Luiz C. S. , Silva Carlos E. T. , Soares Lorena L. O. , Santos Hugo F. L. , Castro Bruno B. , Schluter Helga E. P. , Ferreira Marcus V. D. , Martins André L.
Published: May 2022

Inorganic scaling is a phenomenon of common occurrence both in nature and in industrial operations. In general, its effect can be highly detrimental for the oil industry, as fouling can take place in different stages of the production, from the well bore and downhole production control valves to upstream primary oil processing and separation equipment. The deposition of precipitated crystals on pipe walls and valves can result in severe production decline. Despite the high costs involved in the design and operation of separate lines for additive injection, chemical inhibition is typically the solution adopted by the oil companies to mitigate scaling. The purpose of the present work is to show results of a large scale laboratory pipe flow experiments to evaluate the performance of non-chemical solutions to mitigate and control calcium carbonate scaling. Magnetic, electromagnetic and ultrasound devices have been tested in a set up that simulates the mixing of two incompatible brine solutions that cause precipitation and deposition of calcium carbonate for a high Reynolds number pipe flow. The performance of the devices is evaluated from pressure drop measurements along the pipe, carbonate deposited mass on the pipe wall and reduction of pipe diameter. Additional results comprise evaluation of particle size distribution of the precipitated crystal, scanning electron microscopy, x-ray diffraction for identification of the crystalline structure and pH and conductivity. Results show that the magnetic field furnishes a beneficial effect, as it delays the time observed for the onset of flow restriction in both pipe and valve. The scaling phenomenon is shown to slow down and the delay for the increase in the measured pressure drop range between two to four times in comparison with the tests conducted without the magnetic field. Ultrasound devices are also shown to provide remarkable impact on the delay of the appearance of the scaling effects. The ultrasound field influences the precipitation phenomena so that particle sizes are kept at very small values, which prevent crystal deposition. The main contribution of the present work is to provide an evaluation method of anti-scaling devices based on large scale experiments, which are fairly representative of real field applications.
Introduction of a New BCC Continuous Stirred Tank Reactor Inhibitor BCIn Screening Method for Chemicals in Controlling Inorganic Scales in Oil/Gas Production
Authors: Paudyal Samridhdi , Dai Zhaoyi , Dai Chong , Ko Saebom , Wang Xin , Li Wei , Leschied Cianna
Published: May 2022

Inorganic scales such as calcite, barite, gypsum, celestite are some of the most common scales found in oil field brines. The scale problems are generally treated with different types of inhibitors depending upon the reservoir conditions. In this paper, a newly developed BCC Continuous Stirred Tank Reactor Inhibitor screening method BCIn method will be discussed that uses Continuous Stirred Tank Reactor (CSTR) theory which has been demonstrated to work for analyzing inhibitors efficiency on the inorganic scales formed in oil/gas production. The method has been shown to be more accurate and efficient than the methods commonly used in industrial laboratories. The BCIn CSTR method varies the inhibitor concentration so that constant feeding of the same background solution maintains a constant supersaturation and volume as the inhibitor concentration exponentially decreases. The inhibitor concentration decreases exponentially to below the critical nucleation concentration (Ccrit) and thereby supersaturated brine tends to precipitate rapidly. The induction time is used to compare the efficiency of the inhibitors. The apparatus is designed so that the partial pressure of CO2, pH, temperature (T)and saturation index (SI) can be precisely controlled which makes it suitable for most of the inorganic scales including calcite, barite, CaSO4's etc. The BCIn method was used to rank 18 common inhibitors under various brine conditions, including the effect of SI, T, pH for sulfate scales and additionally ratio of Ca2+/HCO3− for calcite and was investigated by comparing the critical concentration (Ccrit). It was also found that the critical concentration (Ccrit) from CSTR method has a good correlation with the MIC from batch tests so that it can be used as fast ranking to estimate minimum inhibitor concentration (MIC) values. This study provides a simple and reliable solution for conducting scale inhibition tests in an efficient and economical manner.
Prevention of Inorganic Scale in ESPs - A Holistic Review of Scale Inhibitor Deployment Options
Authors: Johnston Clare Jennifer , Jordan Myles Martin
Published: May 2022

Electrical Submersible Pump (ESP) failures have a range of root causes from reservoir solids/ sand, fracture proppant and asphaltenes within the intake assembly of the pumps to deposition of different types of inorganic scale on the motor. The formation of such scale deposits is not unusual, and the mechanism of formation is well understood but the fact that scale deposition and associated pump failures can be observed to occur at water cuts of <1% is less well understood. Treatments with scale inhibitor via continual injection are not always successful at such low water cuts and failure to inhibit scale can also be a result of poor understanding of the mixing point of inhibitor and brine vs the location of onset of scale formation. The deployment of conventional scale squeeze treatments can be associated with significant oil production losses which are commonly attributed to the treatment of low water cut wells with aqueous based scale inhibitors, and operational issues may be caused by the requirement to pull the pump if a bypass valve is not present.

This paper outlines the development of an effective treatment strategy for production wells that suffered significant performance impairment at water cuts below 5% due to carbonate scale deposited within the ESPs. These wells were treated with a mutual solvent and an oil soluble scale inhibitor squeeze treatment. Field results agreed with the laboratory qualification studies showing that the wells treated did not suffer any reduction in oil production rate and the ESPs were effectively protected from carbonate scale deposition.

This work was extended, and applications carried out within offshore fields in the GOM and West Africa where scale inhibitor was applied in fracture fluids programs used for frac pack operations to provide scale inhibition but eliminating the need for an initial squeeze at low water cut. The development of scale inhibitor compatible with the fracture fluids eliminated the need for expensive well intervention until the water cut of the wells exceeded 10% whereby the continual downhole injection system was able to protect the ESPs.

The paper highlights the need to understand the implication of the location of the ESP/motor within the completion in each well to allow assessment of the best scale inhibitor deployment strategy in each case. The selection of treatment strategy is discussed, along with the laboratory qualification studies required to select appropriate inhibitors. Case history data demonstrating successful deployment in the field for continual injection, solid inhibitors and squeeze application are presented, along with analysis of the risk factors to be considered when reviewing the scale formation potential over the lifecycle of a well in new field developments.
Subsurface Scale Diagnosis and Remediation to Uplift Oil Production
Authors: Wang Wei , Wei Wei , Nash Derek C. , Kidd Sam C. , Terry Clinton C. , Popp Nick G. , Sablok Ritesh , Dixit Rahul
Published: May 2022

Scale formation at the subsurface can block perforations, fractures, and pore throats in the near-wellbore region, causing formation damage and loss of well productivity. This paper presents a field case study with an integrated data analysis approach and conceptual model on the diagnosis, remediation, and control of subsurface scale formation.

Unlike scale deposits in production tubing or topside facility, subsurface scale deposits cannot easily be collected or visually observed due to operational uncertainty/difficulty/cost, and safety considerations. In this study, integrated data analysis and scale modeling based on field conditions and water chemistry data from downhole formation water samples, preserved core samples, completion brines, and produced water samples were utilized to diagnose subsurface scale formation and help develop remediation strategy for a deep water well with significant production underperformance (50%+ lower than expected).

MDT (modular formation dynamics tester) water data from this field can be categorized into 3 groups with higher (Type 1), medium (Type 2), and lower (Type 3) concentrations of Cl-, Ca2+, and Ba2+. A novel mathematical algorithm was developed and successfully implemented to calculate produced water source allocation and the composition of produced formation water over time. The calculated produced formation water chemistry data is consistent with MDT water database with respect to both total ion concentrations and ion-ion correlations. Produced water source allocation results show the produced formation water changed from type 1/2 water-dominating composition to type 3 water-dominating composition over time. Integration of the time-lapse produced water source allocation results, production data, and scale modeling results, and comparison with analog wells indicate potential block-out of production from certain formation zones at the underperforming well. Calcite scale precipitation at subsurface due to completion brine-formation water commingling in the near wellbore region during well completion and shut-in stages prior to production is deemed as a primary cause of the production allocation change and significant production underperformance. Learnings from this study provided an important basis to develop/optimize well remediation and subsurface scale control strategies.

This paper clearly demonstrates an integrated data analysis approach based on historical water chemistry and production profile for subsurface scale diagnosis. Moreover, a conceptual model has been developed to help explain, diagnose, and control subsurface scale formation and its impact on well production underperformance. The developed model is successfully applied and validated in explaining findings/results in this field case study.
The Future of Scale Control – The Impact of Net Zero
Authors: Heath Stephen , Mackay Eric , Bagala Stefano
Published: May 2022

Scale deposition in oil and gas wells is still a major issue in the oil and gas industry as it reduces hydrocarbon production, restricts well access to production logging tools and, in addition, causes safety issues due to blocking and ineffective operation of chokes and valves. Scale is predominantly controlled with chemical scale inhibitors and the most common methods to control scale deposition are through continuous injection and scale squeeze treatments although solid inhibitors can be deployed in ratholes, hydraulic fractures and gravel packs. Non-chemical methods can also be applied and are becoming more common over the last few years especially for calcium carbonate control.

Scale management is clearly still a very important factor for the good health of existing oil and gas wells and the trend towards net zero will only increase this reliance as the need for maximum production from existing assets becomes more pertinent compared to the alternative of developing new fields which will be more carbon intensive.

Existing scale management strategies will also have a CO2 footprint and scale control methods will be reviewed to become more aware of this and to highlight how certain areas of scale management can become more effective and adapt to the changing needs of the energy industry such as the increasing use of enhanced oil recovery (EOR) in both conventional and unconventional fields.

The review will include several areas of scale management including scale prediction risk, chemical and non-chemical treatments, scale inhibitor chemistry from renewable sources, monitoring techniques coupled with improved data processing techniques and automation.

The drive towards net zero has also instigated the development of alternative energy sources to fossil fuels which have resulted in a major focus on projects in geothermal energy and increased the potential for carbon capture, utilisation and storage (CCUS) projects where CO2 captured from heavy industry is transported to site and injected into geological reservoirs for storage and/or enhanced oil recovery.

Scale control will be important to both geothermal and CCUS projects and this paper will highlight examples including scale control in geothermal wells with options for treatment and desirable chemical properties and carbonate scale control in CO2Water Alternating Gas (WAG) injection whilst also demonstrating CO2 storage and enhanced oil recovery (CCUS). In addition, the potential for halite deposition and carbonate mineral dissolution and its impact on rock mechanical integrity during CO2 injection into hyper saline aquifers and depleted oil and gas reservoirs will be discussed.
Enhanced Carbonate Scale Inhibition in a Challenging Environment via Synergistic Inhibitor Molecule Blends
Authors: Jordan Myles , Johnston Michael
Published: May 2022

Control of inorganic sulphate and carbonate scales with polymer, phosphonate and phosphate ester scale inhibitors is well established within the oilfield service industry. The environments in which these chemicals work best have been published, i.e., vinyl sulphonates are very effective for sulphate scale control in low temperatures (Laing and Graham 2003) whereas phosphonates are much less effective under these same conditions but improve at higher temperatures (Jordan et al., 2016). Less well understood is the potential for synergistic interactions with blends of polymers/phosphonates/phosphate esters to give reduced treatment rates, lower chemical discharge volumes and potentially lower treatment cost specifically for carbonate scale control

In this paper evaluation of a North Sea produced water (1,500ppm Bicarbonate, 30ppm Iron and 3,550ppm Calcium ions) will be outlined where a very high carbonate saturation ratio exists within a produced fluids heater resulting in very high inhibitor treatment rates of a MEA phosphonate type scale inhibitor). Dynamic tube blocking tests were carried out to evaluate nucleation inhibition of a range of single component inhibitors before blends of these chemicals including biopolymer/phosphonate and poly aspartic acid/phosphonate where evaluated try to reduce the inhibitor concentration required to control scale formation.

For this challenging carbonate scale environment at a temperature (105°C), it was observed that a biopolymer/currently applied MEA phosphonate blend was more effective than either of the components by themselves, suggesting synergistic interaction. Environmental properties of the inhibitors evaluated played a key role in their selection and has resulted in trial of polymer/currently applied phosphonate being planned for this field. Qualification test results for the incumbent, potential replacement single inhibitor actives and blended inhibitor are presented.

The current regulatory challenges with REACH mean that the methods outlined in this study offer the potential to reduce chemical treatment rate, cost and environmental impact by evaluating the synergistic interaction of the current range of commercially available environmentally suitable scale inhibitors and therefore eliminating the very high registration costs/ time delays to the market associated with new molecule development.
Development of a Green, F22 Compatible Scale Inhibitor for Application in West Africa
Authors: Williams Helen , Adamson Ben , De Subhasis , Bhandari Manoj , Johnston Clare
Published: May 2022

An operator in West Africa required a scale inhibitor for an application with several technical challenges. The scale inhibitor was required to meet the Angolan decree on environmental acceptability, had to be compatible with F22 alloy present in the wellhead, and had to be suitable for application via umbilical. The scale in question was a reasonably harsh barium sulphate condition. A number of chemical formulations were suitable for use with F22, however, these chemicals did not meet the performance requirements set for barium sulphate inhibition.

Testing was conducted starting with corrosion tendency screening, whilst several potential raw materials were checked for their environmental credentials. It was possible to meet the corrosion screening conditions set by the operator with one raw material; however, this did not meet the scale inhibition criteria. Several chemicals were examined in dynamic scale loop testing, with none achieving the required performance. It was decided to evaluate blends of generic scale inhibitors, to assess whether a synergy between two different chemicals could offer improved inhibition performance, whilst still meeting the corrosion rates.

The chemicals selected were known to have lower corrosivity – one a polymer which had been used successfully with F22 alloy, plus another polymer widely used in the North Sea where low corrosivity generally is required along with good environmental properties. This blend was successful in meeting the scale inhibition performance target and was found to offer good compatibility with F22 alloy under application conditions. Furthermore, both chemicals were suitable to meet Angolan decree on environmental acceptability.

The paper describes in detail the development test work carried out for corrosion assessment, inhibitor performance, formulation stability, brine compatibility to select this formulation and highlight the importance of synergistic blends for meeting particularly challenging scaling environments.
Scaling Up: Evaluation of Scale Deposition and Inhibition Under Turbulent Flow Conditions Using a Large Pilot-Scale Test System
Authors: Fyfe Andrew , Nichols David , May Mark , Goodwin Neil , Simpson Caroline , Graham Gardon
Published: May 2022

A pilot-scale test system has been developed to evaluate scale deposition and inhibition under flow conditions that are more representative of the field than conventional laboratory methods. This system has been used to investigate an example of strontium sulphate scaling and the effect of hydrodynamics on the location and the quantity of scale deposit formed.

The approach used in this study involved flowing a large quantity of heated brine through a 1" diameter steel test piece at 5 L/min for several hours in a single-pass system. The test piece consisted of short sections allowing the configuration to be altered and allowing the scale deposited in each section to be quantified. Tests were run with configurations simulating a straight pipe, an ICD nozzle, and a gas lift system to investigate the effect of turbulence and shear stress on scale location and mass. The effect that injection of a chemical inhibitor had on preventing scale deposition in this system was also tested.

The results obtained demonstrated that the flow regime in the test piece had a significant effect on the mass and location of strontium sulphate scale deposits. A much greater quantity of scale was observed when the fluid experienced the increased shear stress and turbulence generated by passing through a narrow restriction, or by the injection of gas into the flow, compared with straight pipe flow. Successful chemical inhibition of surface deposits was demonstrated in this system. The use of smaller scale benchtop tests to demonstrate the effect of saturation ratio on obtaining sufficient deposition in single-pass tests compared with a recirculating approach are also discussed.

Design and implementation of large-scale tests is an important industry tool for laboratory evaluation of scaling in circumstances where conventional test methods do not give sufficient confidence to develop a scale management strategy and a more field-representative method is required. This paper describes an approach for successfully carrying out such tests and demonstrates the breadth of results that can be obtained from them. It also adds to industry knowledge of the effect that regions of high turbulence and shear have on promoting greater scale formation.
Hydrodynamic Simulation Supports Scale Formation in Technical Specification for Downhole Equipment
Authors: Poletto Vinicius Gustavo , Mazuroski Marina Elizabeth , Pereira Fabio Ressel de Assis , Palharini Schwalbert Mateus , Duarte Ferreira Marcus Vinicius , Eduardo Tiago Handerson Torres , De Lai Fernando Cesar , Junqueira Silvio Luiz de Mello , Martins André Leibsohn
Published: May 2022

The huge carbonate reservoirs of the Brazilian pre-salt layer are likely to experience inorganic scale formation, mainly due to calcium carbonate. Emerging wellbore configurations, designed to reduce cost and increase reliability, show some drawbacks as the inability of injecting chemical inhibitors in the open-hole full-electric intelligent completion schemes. Traditionally, scale prediction relies on thermodynamic modeling, having a glimpse on the precipitation potential under static conditions, but neglecting the constructive details of the tools’ geometry and the fluid dynamic influence over the precipitated crystals. This paper details a Euler-Lagrange approach for the modeling of the liquid-solid flow applied to the simulation of scale formation in Internal Control Valves (ICVs). Numerical simulation is performed by the means of the Finite Volume method coupled to the Discrete Element Method (CFD-DEM), obtaining results as the accumulated mass in specific parts of the equipment (fouling hotspots) and the transient pressure uptrend as a consequence of flow blockage. The fouling forms as the particulate agglomerates adhere to the walls under the effects of turbulence and the adhesion force set up between particle-particle and particle-wall, hindering the flow due to the four-way-coupling between phases. Thus, the results compute the solids deposition that depends on the valve geometry, rather just the precipitation rate. Additionally, the simulation may be run by the Finite Volume Method coupled to the Discrete Phase Method (CFD-DPM) with an associated operation of remeshing. The fouling consists in computing the accumulated mass over the equipment surface and deforming the geometry to represent the obstruction. The numerical results are useful for the equipment technical specification, specifying the level of scale the valve has to withstand in a time window and also quantify acceptance criteria in terms of the pressure increase and the adhered mass. It is also possible to compare concurrent geometries in terms of reliability and propose design upgrades.