bluuebunny/crossref_metadata_2025 huggingface dataset:
PENGARUH PERENDAMAN AIR PDAM TERHADAP KEKERASAN ENAMEL GIGI PASKA HOME BLEACHING KARBAMID PEROKSIDA 20%
Authors: Safatullah Aqshall Ilham , Wardhana Agung Satria , Diana Sherli , Oktiani Beta Widya , Dewi Renie Kumala
Published: April 2024

Background: One of the treatments to overcome the problem of discolored teeth is to do tooth whitening or bleaching. The tooth whitening agent that is often used is carbamide peroxide which is applied directly to the tooth enamel surface. Several factors that can affect tooth enamel are the degree of acidity or potential hydrogen (pH), acid concentration, dissolving time and the presence of calcium-like ions. Communities in Banjarmasin City still frequently use PDAM water for consumption and for their daily needs. Objective: To analyze the effect of immersing PDAM water and distilled water on the hardness of tooth enamel after the application of 20% carbamide peroxide. Methods: This study used a true experimental method with a posttest-only with control group design consisting of 4 treatment groups namely positive control PDAM water, negative control Aquatic water, group 1 carbamide peroxide 20% and PDAM water, and group 2 carbamide peroxide 20% and distilled water. Tooth enamel hardness was measured using a Vickers microhardness tester. Results: analysis of the One Way Anova test with Post-Hoc Bonferroni showed that there was a significant difference in violence in each group (p>0.05). Conclusion: There is an effect of PDAM water after application of 20% carbamide peroxide on the hardness of enamel on teeth.Keywords: Carbamide Peroxide 20%, Discolored, Enamel Hardness, PDAM
HUBUNGAN PENGETAHUAN PEMELIHARAAN KESEHATAN GIGI TERHADAP KONDISI INDEKS OHIS PADA SISWA DIKTUBA SPN POLDA KALSEL
Authors: Danendra Muhammad Arya , Setyawardhana R. Harry Dharmawan , Wibowo Diana , Wardani Ika Kusuma , Dewi Renie Kumala
Published: April 2024

Background: Dental and oral health problems in Indonesia are quite high based on the 2018 Riskesdas data. According to Blum's theory, the high number of dental and oral health problems can be caused by four main factors which include behavior, environment, health services and heredity which are based on a lack of knowledge about the importance of maintaining dental and oral health. Objective: This study aims to analyze the relationship of knowledge about maintaining dental health and oral hygiene conditions in students of the SPN Polda South Kalimantan dictuba. Methods: This research is an analytic observational study with a cross sectional approach. The sampling technique used simple random sampling with a total sample of 35 people. Test analysis using the SPSS application with the somers'd method. Results: The results of the study showed that knowledge of dental and oral health was a good level of knowledge and the OHIS index was included in the good category. Conclusion: There is a significant relationship between the knowledge of dental health maintenance with the OHIS index on students of the South Kalimantan Regional Police SPN Diktaba.Keywords : Knowledge, Maintenence, OHIS, Police
STUDI LAYANAN PERPUSTAKAAN SEBAGAI SUMBER BELAJAR DI SEKOLAH MENENGAH ATAS
Authors: Wahyudi Diky , Mastur Mastur
Published: April 2024

Layanan perpustakaan pada saat pandemi Covid-19 ini memang belum berjalan dengan maksimal, karena pembatasan aktivitas yang ada di sekolah tersebut sehingga siswa tidak bias berkunjung dan meminjam buku secara maksimal. Penelitian ini bertujuan (1) untuk mengetahui kondisi faktual layanan perpustakaan sebagai sumber belajar, (2) untuk mengetahui faktor apa saja yang menghambat layanan perpustakaan sebagai sumber belajar selama pandemi Covid-19. Jenis penelitian ini adalah penelitian deskriptif, dengan pendekatan kualitatif yang mana untuk mendapatkan data penelitian melalui observasi, wawancara dan dokumentasi. Teknik analisis data meliputi pengumpulan data, reduksi data, penyajian data dan penarikan kesimpulan. Hasil penelitian menemukan bahwa kondisi faktual layanan perpustakaan memiliki kekurangan dalam fasilitas seperti koleksi buku dan komputer, suasanan ruangan yang masih kecil, akses informasi yang kurang berkembang, layanan pada referensi yang masih perlu peningkatan dan faktor penghambat pada layanan perpustakaan yaitu pandemi Covid-19 yang mengakibatkan siswa tidak bisa berkunjung, kurangnya fasilitas pendukung seperti komputer dan WiFi, belum tersedianya website perpustakaan, dan kurangnya petugas di perpustakaan. Penelitian ini direkomendasikan untuk sekolah agar dapat dijadikan saran dalam meningkatkan layanan perpustakaan sebagai sumber belajar
PENGEMBANGAN VIDEO PEMBELAJARAN PADA MATA PELAJARAN BAHASA INGGRIS DENGAN PENDEKATAN PROBLEM BASED LEARNING MATERI GRAMMAR TO BE KELAS 7 SMP NEGERI 2 MUARA UYA
Authors: Yandi Mul , Salim Agus , Satrio Adrie
Published: April 2024

Penelitian ini dilakukan dengan adanya permasalahan keterbatasan media pembelajaran disalah satu SMPN  2 Muara Uya. Penelitian ini bertujuan untuk : (1) mengembangkan video pembelajaran grammar to be dengan pendekatan problem based learning. (2) menguji hasil validitas video pembelajaran grammar to be untuk kelas 7 SMP. (3) mengetahui efektivitas video pembelajaran dalam proses pembelajaran siswa dengan pendekatan problem based learning. Penelitian ini menggunakan metode penelitian dan pengembangan (R&D), dan model pengembangan 4D. Teknik pengumpulan data dalam penelitian ini ialah observasi, wawancara, dan angket. Data yang dikumpulkan tersebut dilakukan dengan cara kualitatif dan kuantitatif deskriptif. Hasil penelitian sebagi berikut : (1) pengembangan video pembelajaran grammar to be melalui 4 tahapan model 4D meliputi : a) tahap pendefinisian, b) tahap perencanaan video pembelajaran, c) tahap pengembangan video pembelajaran, dan d) tahap penyebarluasan media pembelajaran. (2) kelayakan video pembelajaran grammar to be terdiri dari : ahli materi mata pelajaran berpredikat baik 75%, ahli media pembelajaran mendapatkan predikat sangat baik 89%, dan ahli naskah bahasa mendapatkan hasil baik 79%. (3) efektivitas penggunaan video pembelajaran terlihat dari perbedaan dalam penerapan media dengan pendekatan problem based learning terhadap hasil belajar siswa. Nilai rata-rata setelah menggunakan media 92%, lebih tinggi sebelum menggunakan media 58%. Dapat dikatakan bahwa video pembelajaran pada mata pelajaran bahasa inggris materi grammar to be dengan pendekatan problem based learning dapat meningkatkan hasil belajar siswa.
PENGEMBANGAN E-BOOK HYPERCONTENT BERBASIS KVISOFT FLIPBOOK MAKER SEBAGAI SUMBER BELAJAR MATA PELAJARAN SENI BUDAYA SMP
Authors: Puspa Rani Putri Elvira , Mansur Hamsi , Mastur Mastur
Published: April 2024

Pendemi covid-19 merupakan situasi darurat sedunia oleh tersebarnya coronavirus yang mana penyebarannya melalui kontak fisik dan udara. Coronavirus menyebabkan adanya pembatasan sosial, sehingga melahirkan kebijakan baru dalam pendidikan nasional yang menerangkan tentang belajar dari rumah dengani pembelajaran daring. Sehubung dengan hal tersebut dampak kemajuan teknologi terhadap siswa dan guru pada masa pandemii covid-19 ini yaitu penggunaan perangkat elektronik yang dimanfaatkan dalam pembelajaran, hal ini menjadi peluang peneliti untuk mengalihkannya sebgai sumber belajar. Berdasarkan hal tersebut dilakukan Pengembangan ebook hypercontent berbasis kvisoft flipbook maker sebagai sumber belajar mata pelajaran seni budaya kelas VIII SMP Negeri 23 Banjarmasin. Adapun mata pelajaran seni budayaadipilih karena mata pelajaran ini sukar dipahami sehingga perlu sumber belajar yang dapat memperjelas materi, salah satunya menggunakan hypercontent yang menghubungkan dengan berbagai Platform sumber belajar seperti video, suara, dan lainnya ditandai dengan penggunaan QR Code didalamnya. Pengembangan ini menggunakan model 4D yang memiliki 4 tahapan pengembangan yaituudefine, desain, develope dan dessiminate. Hasillakhir penelitian ini berupa produk yang layak sebagai sumber belajar berdasarkan uji validasi oleh ahli materi, ahli media dan ahli pembelajaran.
PEMANFAATAN MEDIA KAHOOT UNTUK MENINGKATKAN KERJASAMA DAN HASIL BELAJAR PADA MATA PELAJARAN IPS SISWA KELAS VIII DI SMPN 2
Authors: Salim Hidayat Nur , Arrum Dalu Zaudah Cyly , Utama Agus Hadi
Published: April 2024

Penelitian ini adalah untuk melihat bagaimana pemanfaatan media kahoot yang sudah cukup familiar digunakan dalam proses belajar dan mengajar (PBM) di dalam kelas. Tujuan penelitian ini adalah untuk mengetahui pemanfaatan media kahoot dengan model kooperatif tipe STAD, kemudian untuk mengetahui bagaimana kerjasama siswa sebelum dan sesudah saat menggunakan media Kahoot dengan model kooperatif tipe STAD, yang pada akhirnya adalah untuk dapat mengetahui apakah ada peningkatan hasil belajar siswa setelah menggunakan media kahoot dengan model kooperatif tipe STAD. Penelitian ini mengambil sampel di kelas VIII pada mata pelajaran IPS SMPN 2 Kusan Hilir dengan menggunakan desain penelitian mixed method kuantitaif dan kualitatif. Instrumen dan analisis datanya meliputi lembar observasi pemanfaatan, lembar observasi kerjasama siswa, pedoman wawancara kerjasama siswa, dan tes hasil belajar siswa yang dianalisis secara kuantitatif dan kualitatif. Hasil penelitian ini memberikan gambaran bahwa pemanfaatan media kahoot pada PBM tiga kali pertemuan adalah 84,84% yang termasuk dalam kategori sangat baik. Kemudian hasil kerjasama siswa yang didapatkan sebelum tindakan sebesar 40%, sedangkan setelah tindakan pada pertemuan I adalah 63%, pada pertemuan II meningkat menjadi 80%, dan pada pertemuan III terus meningkat menjadi 93% yang termasuk dalam kategori baik. Hasil belajar menunjukkan telah terjadinya peningkatan 62,96% pada pertemuan I, 77,78% di pertemuan II, dan 96,56% di pertemuan III. Dengan demikian disimpulkan bahwa pemanfaatan media kahoot dengan model kooperatif tipe STAD dapat meningkatkan  kerjasama dan hasil belajar siswa pada mata pelajaran IPS kelas VIII di SMPN 2 Kusan Hilir
A Rare Case: Stenosis Doudeni Congenital et Causa Ladd Band Eet Causa Malrotation with Situs Inversus in 12 Days Old Baby
Authors: Thaihutu Yhohan Ziantprayogi , Rifa’i Muhammad Syahibuddin
Published: April 2024

We are sharing a rare presentation of congenital duodenal obstruction with combined intrinsic and extrinsic causes with situs inversus, namely, duodenal stenosis with gastrointestinal malrotation in a neonate. The patient underwent successful exploratory laparotomy, Ladd's procedure, and appendicectomy were carried out. Early recognition of signs and symptoms, prompt corrective surgery, and adequate optimization of metabolic components post-operatively are important to determine the decreased morbidity and mortality of neonates.
Scented Root Extract (Vetiveria zizanioides L.) Inhibits Bacillus cereus Growth In-Vitro
Authors: Hapsari Bramantyas Kusuma , Sahabuddin Rosdiana , Vebrianty Rizky Indah
Published: April 2024

Bacillus cereus, a gram-positive bacterium with a high incidence of causing infection through food, is a common cause of infection. Plant extract from Vetiveria zizanioides (L.) contains alkaloids, flavonoids, saponins, and tannins, and has been demonstrated to exhibit antibacterial action against other bacteria such as Staphylococcus aureus, Vibrio cholerae, Escherichia coli, Salmonella typhi, and Klebsiella pneumoniae. The purpose of this study is determining the antibacterial activity of vetiver root extract (Vetiveria zizanioides (L.)) against the growth of Bacillus cereus bacteria in vitro. In this experimental study, the inhibition effect of vetiver root extract against Bacillus cereus growth was measured using disc diffusion method. Extract consentraion used in this tudy were 60%, 80% and 100%. The diameter of area with no bacterial growth around disc (inbition zone) was measured and the average of diamter from four independent measurement was used to decide the sensitivity of bacteria towards the extract. The average measurement results from 60 percent concentration of extract were 6.70 mm, 7.04 mm for 80 percent concentration, and 7.05 mm for 100 percent extract concentration. The positive control, Amoxicillin 500 mg, had a diameter of 14.35 mm, whereas the negative control, sterile distilled water, had no impact. Bacillus cereus bacteria growth can be inhibited by Vetiveria zizanioides (L.) extract.
PROJECT-BASED LEARNING: MEMBIASAKAN TANGGUNG JAWAB DAN PRODUK KREATIF MAHASISWA PADA LINGKUNGAN LAHAN BASAH
Authors: Suyidno Suyidno , Mahtari Saidah , Astuti Yanti , Hadianti Raisa
Published: April 2024

Pendidikan sains abad 21 bercirikan tanggung jawab kreatif individu untuk mencipta produk kreatif yang bermanfaat, namun kompetensi tersebut kurang dilatihkan dalam pembelajaran sains. Oleh karena itu, tujuan penelitian ini adalah menganalisis kelayakan buku Project-Based Learning (PjBL) untuk melatihkan produk kreatif dan tanggung jawab kreatif mahasiswa pada lingkungan lahan basah. Penelitian ini menggunakan desain 4D (define, design, develop, and disseminate). Pengumpulan data melalui uji validasi buku oleh 3 pakar pembelajaran sains dan 2 observasi mengamati aktivitas PjBL mahasiswa. Data yang diperoleh dianalisis secara deskriptif kualitatif. Hasil validasi pakar menunjukkan bahwa buku yang dikembangkan termasuk valid dari aspek format, bahasa, isi, maupun penyajiannya. Buku tersebut juga praktis karena mahasiswa mampu melaksanakan tanggung jawab kreatifnya pada setiap aktivitas PjBL dengan baik. Dengan demikian, buku PjBL ini adalah layak digunakan untuk melatihkan produk kreatif dan tanggung jawab kreatif mahasiswa pada lingkungan lahan basah.Kata kunci: Lingkungan Lahan Basah, Produk Kreatif, Project-Based Learning, Tanggung Jawab Kreatif. 21st-century science education is characterized by individual creative responsibility to create useful creative products, but these competencies are not sufficiently trained in science learning. Therefore, the purpose of this study was to analyze the feasibility of a Project-Based Learning book to train students in creative products and creative responsibilities in wetland environments. This research used the 4D design (Define, Design, Develop, Disseminate). Data collection through book validation test by 3 science learning experts and 2 observations observing student PjBL activities. The data obtained were analyzed descriptively and qualitatively. The results of expert validation showed that the book developed was valid from the aspects of format, language, content, and presentation. The book is also practical because students can carry out their creative responsibilities in each project activity well. Thus, this book is suitable to be used to train students on creative products and responsibilities in a wetland environment.Keywords: Creative Products, Creative Responsibility, Project-Based Learning, Wetland Environment.
PENGEMBANGAN TES DIAGNOSTIK FIVE-TIER UNTUK MENGIDENTIFIKASI MISKONSEPSI PESERTA DIDIK DALAM MATERI HIDROKARBON KELAS XI MIPA
Authors: Fajar Muhammad Rizky , Kusasi Muhammad , Almubarak Almubarak
Published: April 2024

Telah dilakukan penelitian pengembangan instrument tes diagnostik  five-tier model 4D pada materi hidrokarbon. Penelitiaan ini bertujuan untuk mengetahui kevalidan, kepraktisan dan keefektifan dalam pengembangan menggunakan instrumen tes diagnostik five-tier untuk untuk mengetahui tingkat miskonsepsi pada peserta didik materi hidrokarbon. Subjek penelitian adalah peserta didik kelas XI MIPA 2 SMAN 1 Sungai Tabuk dengan jumlah siswa 23 orang. Pengambilan sampel menggunakan teknik random sampling. Hasil penelitian menunjukkan (1) Terdapat empat konsep hidrokarbon yang memiliki persentase diatas 50% mengalami miskonsepsi konsep-konsep hidrokarbon tersebut iyalah pengelompokan hidrokarbon, tata nama hidrokarbon, sifat fisik hidrokarbon dan isomer. Dari tingkat kevalidan diperohel hasil sangat valid yang dipeoleh dari para ahli dan jawaban siswa yang diukur menggunakan SPSS. Kepraktisan diperoleh dari peserta didik yang mengisi angket dengan memberi skor 4 hingga 5 yang menandakan intrumen sudah dapat diterima dan diperkuat dengan wawancara kebeberapa peserta didik. Keefektifan  diperoleh hasil dimana instrument sudah dinyatakan efektif karna sudah dapat mengukur tingkat pemahaman peserta didik dan diperkuat dengan hasil dari tingkat kesukaran, daya pembeda, reabilitas, dan validitas. Oleh karena itu, instrument tes diagnostik five-tier ini layak digunakan untuk mengukur dalam materi hidrokarbon.
RANCANG BANGUN MESIN PENGADUK PUPUK ORGANIK CAIR (POC)
Authors: Muttaqin Katiko Imamul , Nur Raybian
Published: April 2024

Melalui kebijakan Pemerintah Indonesia dalam mencapai ketahanan pangan dalam negeri maka kegiatan dibidang pertanian dan perkebunan kembali dilirik oleh para peneliti untuk meningkatkan hasil produksi pertanian dan perkebunan. Beberapa upaya dalam mendukung peningkatan produksi pertanian dan perkebunan diantara yaitu menghasilkan sebuah alat yang membantu/mempermudah dalam proses kegiatan produksi. Penelitian ini bertujuan untuk merancang dan mengetahui performa dari sebuah mixer pengaduk pupuk organik cair (POC) yang nantinya akan digunakan di Desa Masingai II Kabupaten Tabalong oleh para kelompok tani. Pada penelitian ini menggunakan metode experimental pada mesin POC yang dibuat. Hasil penelitian menunjukkan mesin bekerja secara optimal dengan penggunaan daya 426 W yang menghasilkan putaran 66 rpm dengan konsumsi listrik sebesar 0,0007 kWh dengan kapasitas yang diaduk hingga 200 liter. Through the Indonesian Government's policy to create food security and improve farmers' welfare, researchers are looking at agricultural and plantation activities again to increase agricultural and plantation production. Some efforts to support increased agricultural and plantation production include producing a tool that helps/makes the production process easier. The purpose of this study is to design and calculate the performance of liquid organic fertilizer (POC) mixers which will later be used in Masingai II Village, Tabalong Regency by farmer groups. Experimental methods were used in the study. The research results show that the machine works optimally using 426 W of power which produces 66 rpm rotation with an electricity consumption of 0.0007 kWh every minute.
PENGARUH FRAKSI VOLUME DAN SUSUNAN SERAT KOMPOSIT POLYESTER-SERAT ECENG GONDOK TERHADAP NILAI KONDUKTIVITAS TERMAL
Authors: Akbar Saputera Muhammad Ilham , Subagyo Rachmat , Muchsin Muchsin
Published: April 2024

Komposit dibuat dengan menggunakan resin poliester sebagai matriks dan serat eceng gondok sebagai penguat. Dari pengujian nilai konduktivitas yang dilakukan pada komposit serat eceng gondok diperoleh nilai konduktivitas termal tertinggi pada komposisi 15% serat-85% resin dengan variasi acak letak serat sebesar 0,063 W/m°C, disusul serat 20%- Lokasi serat acak resin 80% sebesar 0,060 W/m°C, kemudian disusul serat acak resin 25%-75% lokasi serat acak sebesar 0,050 W/m°C. Untuk komposisi resin 15% serat-85% dengan variasi letak serat sejajar diperoleh nilai sebesar 0,059 W/m°C, disusul resin 20% serat-80% dimana seratnya sebesar 0,056 W/m°C, disusul kemudian dengan 25% fiber-75% resin letak parallel fiber sebesar 0,043 W/m°C Pada pengujian struktur mikro terlihat bahwa semakin bervariasi fraksi volume maka semakin banyak void yang terdapat pada komposit. Nilai konduktivitas termal dan struktur mikro menjadikan komposit serat eceng gondok dapat menjadi referensi terkini sebagai bahan baku furniture atau bangunan yang cukup baik. Composites are made using polyester resin as a matrix and hyacinth fiber as reinforcement. From the testing of conductivity values carried out on the water hyacinth fiber composites obtained the highest thermal conductivity value in the composition of 15% fiber-85% resin with a variation of random fiber location of 0.063 W/moC, followed by 20% fiber-80% resin random fiber location of 0.060 W/m°C, then followed by 25% fiber-75% resin random fiber location of 0.050 W/m°C. For the composition of 15% fiber-85% resin with variations in the location of parallel fibers obtained a value of 0.059 W/m°C, followed by 20% fiber-80% resin where the fiber is equal to 0.056 W/m°C, then followed by 25% fiber-75% resin location parallel fiber of 0.043 W/m°C In testing the microstructure it can be seen that the more varied the volume fraction, the more void that is present in the composite. The value of thermal conductivity and microstructure makes the water hyacinth fiber composite can be the latest reference as a raw material for furniture or buildings that are quite good.
PENGARUH METODE PENDINGINAN MESIN SEPEDA MOTOR SUZUKI NEX TERHADAP KONSUMSI BAHAN BAKAR DAN EMISI GAS BUANG
Authors: Alexander Baimy , Al Banjari Muhammad Arsad
Published: April 2024

Penelitian ini dimaksudkan untuk menilai dampak sistem pendinginan terhadap emisi gas buang dan penggunaan bahan bakar pada sepeda motor. Metode penelitian melibatkan pengujian eksperimen dengan tiga variasi pendinginan, yaitu penggunaan pendinginan normal, semburan udara, dan selimut air. Sepeda motor yang digunakan dalam pengujian adalah Suzuki Nex, dengan parameter RPM diatur pada 3000, 4500, dan 7000, dan penggunaan bahan bakar sejumlah 100 ml selama periode 2 menit. Untuk mengukur emisi gas buang, termasuk CO, CO2, HC, dan O2, digunakan Gas Analyzer, sementara gelas ukur digunakan untuk mengukur sisa bahan bakar yang terpakai. Hasil pengujian menunjukkan bahwa sistem pendinginan normal memberikan efisiensi konsumsi bahan bakar yang lebih baik jika dibandingkan dengan metode lainnya. Meskipun demikian, sistem pendinginan selimut air dapat mengurangi emisi CO dan HC pada RPM yang tinggi. Sebaliknya, pada RPM yang tinggi, sistem pendinginan semburan udara menunjukkan peningkatan emisi CO dan HC, mengindikasikan efisiensi yang lebih rendah dalam kondisi tersebut. Penelitian ini memberikan pemahaman yang lebih mendalam tentang dampak sistem pendinginan terhadap emisi gas buang dan penggunaan bahan bakar pada sepeda motor. This research is intended to assess the impact of the cooling system on exhaust gas emissions and fuel usage in motorcycles. The research methodology involves experimental testing with three cooling variations: normal cooling, air injection, and water jacket. The motorcycle used in the testing is the Suzuki Nex, with RPM parameters set at 3000, 4500, and 7000, and fuel usage of 100ml over a 2-minute period. A Gas Analyzer is employed to measure exhaust gas emissions, including CO, CO2, HC, and O2, while a measuring cup is used to gauge the remaining fuel. The test results indicate that the normal cooling system provides better fuel consumption efficiency compared to other methods. However, the water jacket cooling system can reduce CO and HC emissions at high RPMs. Conversely, at high RPMs, the air injection cooling system shows an increase in CO and HC emissions, indicating lower efficiency in those conditions. This research provides a deeper understanding of the impact of the cooling system on exhaust gas emissions and fuel usage in motorcycles.
Analyzing the Dynamics of the Romanian M&A Market. Empirical Evidence Regarding the Premiums Paid in Transactions
Authors:   Alexandru Ioan Cuza University of Iasi, Romania, AEVOAE George Marian
Published: April 2024

Corporations often acquire stakes in other companies. These stakes do or do not grant them control but they definitely allow the acquirers to use target companies’ resources to increase their profitability, access technological progress and innovation, develop products, or obtain dividends, as a part of their strategic transactions. The main objective of this article is to assess the stake purchased in acquisitions, based on information related to the size of the target companies and the premium paid, based on a sample of 2.565 acquisitions which involved at least one Romanian company, for the 2010-2018 period of time. The result show that the influence is negative and significant for the entire sample. When considering the accounting practices of the target companies, large stakes are purchased in companies which apply local GAAP, compared to IFRS. The second part of the study focuses on Romanian mergers, which are regulated separately by the OMPF no. 897/2015. In the case of these transactions, the target companies, in most cases, report a negative book value of equity.
Antioxidant potential of the sap of the Croton lechleri Müll. Arg. stem (Euphorbiaceae)
Authors: Perín Simone Letícia , Chendynski Leticia Thaís , Gomes Sandra Inês Adams Angnes , Giusti Edneia Durli
Published: April 2024

A planta Croton lechleri é utilizada pela população indígena e ribeirinha devido seu poder curativo e anestésico. O objetivo da pesquisa foi avaliar a quantidade de compostos fenólicos totais e as propriedades antioxidantes da seiva extraída do caule da planta conhecida como Sangue de Dragão (Croton lechleri) para utilizar o extrato natural como alternativa renovável aos antioxidantes sintéticos presentes na indústria de alimentos e de biodiesel. As condições de extração e a atividade antioxidante destes compostos bioativos foram otimizadas através de planejamento fatorial fracionado. As variações foram: solvente (água pura, etanol 50%, etanol 100%), temperatura (50 °C, 70 °C e 90 °C) e tempo (30 min, 60 min, 90 min). Nove ensaios foram avaliados com o software Statist 12®. O teor de compostos fenólicos totais variou de 92,22 ± 1,35 a 193,29 ± 1,93 mg de EAG/g de seiva e a atividade antioxidante pelo método ABTS de 15,17 ± 0,08 a 26,80 ± 0,04 mM TE/g de seiva. A análise da resposta global e suas equações permitiu verificar que o etanol 50% (v/v) foi mais eficaz na extração de compostos fenólicos totais e atividade antioxidante nas condições de extração a 90°C e o menor tempo de 30 minutos.
Efectos del salario social básico sobre la probabilidad de obtener un empleo en Asturias
Authors:   Universidad de Oviedo, Rodriguez-Gutierrez César , Canal Domínguez Juan Francisco ,   Universidad de Oviedo
Published: April 2024

This research is mainly aimed at analysing the impact of benefiting from a minimum income scheme, the Basic Social Salary, a regional program that guarantees a permanent minimum income in Asturias, on the likelihood of getting a job. The data provided by the Public Employment Service of the Principality of Asturias in relation to job seekers and contracts between October 2021 and October 2022, has allowed as to state that the two variables that have a more negative and stable impact on the likelihood of getting a job are the fact of benefiting from such minimum income scheme and the time the person has been registered as unemployed at the Public Employment Service.
Evaluation of Multi-Cluster Fracturing Placement with Multi-Arm Caliper
Authors: Li H. , Kalinin D. , Bruce A. , Bukovac T. , Kurniadi S.D.
Published: April 2024

With the increasing application of horizontal well drilling, multistage hydraulic fracturing has become widespread in unconventional resources. The production data often reveal that the production contribution of each cluster is highly non-uniform, indicating a corresponding inconsistency in fluid and proppant distribution. Understanding the distribution is crucial to completion designs aiming for a more even cluster contribution. In our study, we developed a new approach for evaluating the distribution of fracturing materials using multi-arm caliper data.

Most perforations are performed perpendicular to the casing, and perforation holes are eroded as fracturing fluid flows through them. Because casing fluid flow is unidirectional, the erosion is asymmetric. Modern multi-arm caliper tools exhibit enough resolution to accurately resolve casing inside-diameter profiles. Our systematic workflow, perforation asymmetry analysis (PAA), assesses erosion and correlates it with material distribution. First, the peak in the inside-diameter profile representing a perforation hole is identified. Subsequent analysis of the profile’s asymmetry indicates the degree of erosion. Based on the analysis of individual perforation holes, the material entry for a cluster and the material distribution among clusters are modeled.

Well C-2H, drilled in the Beetaloo sub-basin, Northern Territory, Australia, was stimulated with 21 hydraulic fracturing stages using the plug-and-perf technique. After well cleanup, a 24-arm caliper was run in the hole with the objective of understanding casing ovality after stimulation. The analysis encompassed different combinations of cluster numbers, perforation holes, treating fluids, and pumping rates. The results helped to iterate the completion and treatment design for an upcoming well.

This new method can evaluate perforation hole erosion due to fracturing materials, which can be subsequently translated into insights about fracturing placement distribution. Compared with other measurements, this is an indirect method but exhibits good data availability and cost-effectiveness. Initially, it can be used and evaluated together with other solutions as a step toward subsequent precise standalone analysis.
Low-Carbon Oil Using Dimethyl Ether (DME) Produced from Green Hydrogen and Captured CO2
Authors: Farajzadeh R. , Khoshnevis N. , Solomon D. , Masalmeh S. , Bruining J.
Published: April 2024

Hydrocarbon fuels are widely recognized as significant contributors to climate change and the rising levels of CO2 in the atmosphere. As a result, it is crucial to reduce the net carbon intensity of energy derived from these fuels. This study explores the feasibility of using dimethyl ether (DME), produced through the hydrogenation of CO2, as a low-carbon method for generating electricity from hydrocarbon fuels. The proposed approach involves capturing the emitted CO2 during combustion and utilizing it to produce the necessary DME in a closed cycle. It is shown that for a mature reservoir in the Middle East, this method can mitigate approximately 75% of the CO2 emissions released from burning the produced oil. By incorporating zero-carbon electricity throughout the process, the total abatement of CO2 can reach 85%. Furthermore, the study highlights the importance of improving the DME utilization factor (bbl-oil/tDME). By optimizing this factor, high abatement rates can be achieved. However, it is important to note that implementing this method comes with a high exergetic cost. During a certain period in the field’s lifetime, the invested energy exceeds the energy produced. The stages with the highest exergy consumption are CO2 capture and hydrogen production.
Re-Associated Polymer Particle Gels by In-Situ Nanosilica Gels for Water Shutoff Applications in Fractured Reservoirs
Authors: Almohsin Ayman , AlMutairi Saad , Alharbi Bader , Al-ShaikhAli Anaam
Published: April 2024

Re-association of preformed particle gel via colloidal nanosilica is an innovative kind of preformed particle gel of which particles can bond together to form a reinforced bulk gel system after being placed in a fractured having unwanted water production. The objective is to minimize water production of the oil wells by treating the non-productive conductive paths, mainly referred to as reservoir heterogeneity having natural or induced fracture which is connected to water aquifer.

The ultimate objective of this research is to evaluate the newly developed systems for water shutoff application in fractured reservoir, using different testing methodologies. Thermogravimetric Analysis (TGA) and dynamic mechanical analysis were conducted to benchmark performed particle gels swelled in water and nanosilica/activator. In addition, curing time (re-association) must be defined to allow safe pumping operation of the fluid through the tubular and into the target zone; therefore, the re-association (gelation time) of the particle gels were investigated. A coreflooding test was carried-out to evaluate the plugging efficiency of the newly developed technology using an induced fractured core plugs.

TGA thermograms of polymer particle gels swellen in water and Nanosilica revealed that the semi-quantitative result indicated that the total weight losses (TWL) of the samples are approximately 47wt.% and 18 wt.%, respectively, while the residual masses are found to be approximately 53 wt.% and 82 wt.%, respectively. Furthermore, the results obtained from dynamic mechanical analysis, the storage modulus (G') was much higher with particle gels swelled in in-situ nanosilica than swelled in water, the newly developed composite gels behave more solid-like material. Additionally, the (re-association of the particle gels) curing time can be controlled by adjusting activator concentration from minutes to hours, which allows a predictable and controllable pumping time. The core flooding findings unveiled that this robust newly developed material efficiently plugged the facture core with high pressure of 2000 psi.

Evolving technologies are required in the oil industry to overcome the existent challenges. Re-association of preformed particle gel via In-situ nanosilica is a novel method to procedure a robust bulk gel system for water control from fractured reservoirs.
Nitrogen Huff and Puff: Novel Method for Enhancing Liquid Production in the Brown Fields of the Mehsana
Authors: Meena M. , Chanchlani K. , Kumar A. , Chouhan V.
Published: April 2024

Nitrogen cyclic stimulation is a three-stage process, which involves nitrogen injection, soaking, and production for a well. Due to low solubility and dissolution, large amount of nitrogen remains as free gas at high pressure during injection phase. In production phase, oil production rate is high due to various recovery drive mechanisms. The paper will discuss in detail about the changes taking place in the injected nitrogen and reservoir fluid. It will also bring out the challenges faced in implementing this novel technology. The breakthrough cases are discussed with the probable recovery mechanism.

Nitrogen Soaking time is increased to reduce the pressure depletion at the early stage of each cycle. Oil recovery is enhanced by taking advantage of gas cap, gravity differentiation and free gas to oil production. The pressure depletion can be increased at the later stage of each cycle to take full advantage of the solution gas drive and to form a stable foamy oil flow. Nitrogen is more suitable for early application of the cyclic stimulation process. It not only has low cost and good recovery efficiency but can also keep high gas oil contact. Results are quite encouraging for heavy oil fields as compared to light oil fields. This method can be potential choice to the operators for increasing oil production with minimum water cut.

Nitrogen cyclic stimulation is highly efficient techno-economic process. The Asset has realized cumulative gain of 14501 m3 in 52 production wells with reduction in average water cut from 92% to 58% and cumulative nitrogen injection of 2730 KL. The parent company is maintaining the ratio of oil produced to nitrogen injected at 5.3, indicating higher oil gain with the minimum quantity of the nitrogen injected. The Asset is planning to implement this technology at wide scale.
Dynamic Adsorption of CO2 Soluble Amine Surfactants for Foam Assisted Carbon Storage: An Industry-First Quantification Under Reservoir Conditions
Authors: Wu Qianhui , Zhao Lun , Zhao Wenqi , Wu Xuelin , Fan Zifei
Published: April 2024

The success of foam-assisted CO2 enhanced oil recovery and carbon sequestration processes is largely determined by the adsorption level of surfactants in the field. However, the dynamic adsorption behavior of CO2 soluble surfactants, predominately the amine surfactants, remains a challenge due to their unique solubility in brine under most of the reservoir conditions.

The reliability of static surfactant adsorption tests is questionable, especially for switchable amine surfactants, because the testing conditions greatly deviate from the reservoir conditions. For the first time in the oil and gas industry, dynamic adsorption tests of switchable amine surfactants were conducted by injecting a proper amount of CO2 with the surfactant solution at reservoir conditions, where CO2 would be completely solubilized. The dynamic adsorption tests were conducted on dolomite at reservoir conditions, where the effluents were collected every 0.05 PV for high-performance liquid chromatography and pH analyses.

It is found that the pH of the CO2-saturated brine and the charge of the mineral surface are heavily dependent on CO2 pressure, which can therefore affect the surfactant adsorption behavior on minerals. The desired co-injected volume of CO2 under specific reservoir conditions can be predicted by the Peng-Robinson equation of states model and the iPhreeqc geochemistry module. The pressure gradient during the dynamic adsorption test is almost equal to brine injection at the same flow rate, indicating that all the injected CO2 could be essentially solubilized into the aqueous phase. By using this approach, the pH, salinity, brine compositions (including the potential determining ions), surface charge, and mineral wettability can be largely preserved, being capable of reproducing all the essential geochemistry reactions at reservoir conditions during CO2 injection. The pH of effluent indicates that CO2 has been dissolved in brine and good pH control necessary for surfactant solubility has been attained in the core. From the dynamic adsorption tests, the adsorption of amine surfactants on dolomite is small (0.089 mg/g) in the presence of high-pressure CO2, while the static adsorption tests may significantly overestimate the adsorption levels (0.350-0.510 mg/g). It is also found that the static adsorption tests may overestimate the adsorption levels.

Foam-assisted carbon storage using CO2-soluble surfactants has recently attracted great interest in the oil and gas industry. This study provides a robust approach for estimating the adsorption of switchable amine surfactants with good reproducibility, which is more accurate than the existing method of static adsorption. This novel approach is of great importance for decision-makers to quantify the economic feasibility of the foam-assisted CO2 storage process.
Effect of Pressure, Initial Water Saturation, Rock Type and Injection Rate on Oil Recovery and Displacement Efficiency of CO2 Injection in Carbonate Reservoirs
Authors: Masalmeh S. K. , Farzaneh S. A. , Sohrabi M. , AlHammadi M.
Published: April 2024

Miscible gas injection is the most widely applied enhanced oil recovery (EOR) method in light oil carbonate reservoirs, both as tertiary and secondary method. Miscible gas has high displacement efficiency and usually results in a low residual oil saturation (Sorm) in the part of the reservoirs that is contacted with gas. Accurate determination of Sorm and understanding the parameters that affect displacement efficiency are crucial for successful miscible gas EOR projects.

This paper presents a comprehensive experimental program designed to investigate the effect of experimental pressure, pore volume injected, injection rate, rock type and initial water saturation on the displacement efficiency, Sorm and recovery factor of miscible/near-miscible CO2 injection. The CO2 injection experiments were performed using live crude oil at pressures above the minimum miscibility pressure (MMP) using reservoir core samples of up to 1 ft long and 2 in. diameter. All CO2 injection experiments were performed using vertically oriented cores, with gas injection from the top unless stated otherwise.

The experimental results show that: 1-Oil recovery decreases as pressure decreases with Sorm increases by more than 20 saturation units as the pressure decrease from 4250 psi to 2700 psi; 2-CO2 breakthrough was much earlier at lower pressure which leads to more CO2 recycling, 3-The recovery factor is strongly affected by pore volume injected, however, the effect of the CO2 injection volume is much more significant at lower pressure; 4-The injection rate has insignificant effect on oil recovery and Sorm for miscible or near miscible CO2, due to the low IFT between oil and CO2, 5-Rock heterogeneity has a strong effect on oil recovery and CO2 breakthrough and hence on CO2 recycling and economy of the projects., and 6-The presence of mobile water at the beginning of CO2 injection resulted in lower displacement efficiency and increased Sorm. However, this water blocking effect should be determined experimentally for a given reservoir rock/fluid system. The results of this study cannot be generalized for other reservoirs.

The results of this study have important implications for the design and performance predictions of CO2 gas injection. Starting CO2 injection at higher reservoir pressure is recommended due to its superior displacement efficiency and less CO2 recycling due to later breakthrough. However, higher pressure may negatively impact the required CO2 volume, the compression cost and project economics.
Autonomous SRP Optimization Using an Edge-Based Data-Driven Solution
Authors: Gambaretto A. , Yermekova M. , Srivastava S. , Hyder Z.
Published: April 2024

Sucker Rod Pumps (SRPs) are the leading Artificial Lift System (ALS) worldwide for low oil-producing wells. Yet, SRPs have been overlooked in the ongoing wave of digitalization within oil and gas production. SRP operation and optimization processes are outdated and still based on simple field legacy ‘rule of thumb’ practices. This paper presents a simple yet innovative solution that uses an Industrial Internet of Things (IIoT) framework to autonomously optimize SRP production while minimizing pump shutdowns.

The SRP optimization algorithm, rule-based in nature, gathers trending operational data from the controller via a time-moving window. This time window represents a well snapshot that is used to evaluate performance indicators at different operating pump frequencies. These calculated performance indicators, namely Production Indicator (PI), Combined Indicators (CI) and Combined Indicator-Quadratic Penalty (CI-QP), are mainly a function of pump fillage, strokes per minute, and well shutdowns. The PI prioritizes higher well production, while the CI and CI-QP penalizes shutdowns to reduce pump failure rates. The algorithm dynamically evaluates the well performance indicators to recommend and implement an optimal frequency setpoint to the pump controller. This solution has been dockerized and developed as an Edge Application, capable of running directly on-site in an IIoT Gateway device. This application has been tested on eight SRP wells for several months with excellent results. These wells were tested in both PI and CI modes. As a result, inferred production increased by 15% and shutdowns reduced by 29% in average, in all tested wells. The solution provides an easy yet powerful tool that can be scaled to manage multiple wells by providing optimal setpoints based on pump-specific conditions. Additionally, features like user-configurable optimization cycle duration can be included for faster well optimization.

With the advent of the digital oilfield, the solution evaluates trending data by leveraging IIoT to optimize SRP operation using real-time performance indicators of well production and shutdowns. This completely autonomous, edge-based solution requires no manual intervention and can be scaled to hundreds of wells.
Successful Application of a Low Dose Surfactant Injectivity-Aid in a Canadian Polymer Flood
Authors: Roostapour A. , Ramsden-Wood A. , Tudor E. , He K. , Lee J.
Published: April 2024

To achieve a successful polymer EOR application, it is crucial to maintain high polymer injectivity below the fracture pressure. This helps to prevent fracture propagation in the reservoir, which can cause fast breakthroughs, while still enabling the fastest recovery of oil. Laboratory and field testing of the addition of surfactant into a polymer injection system has shown that it can reduce the interfacial tension between injected fluids and reservoir oil, enabling more efficient oil displacement and enhanced sweep efficiency. Additionally, tailored surfactant can modify rock wettability and mitigate polymer retention in the reservoir, thereby improving polymer injectivity.

In a previous paper related to this work, He et al (2024) conducted a detailed laboratory study to select an effective low dose surfactant injectivity-aid for the Atlee Buffalo field in Canada. The study comprised of fluid characterization, thermal stability, interfacial tension (IFT), emulsion tendency, polymer compatibility, and core flood performance testing. It was concluded from the laboratory core flood experimental results that the addition of a unique surfactant, at low concentrations, did indeed enhance both injectivity and oil recovery. This paper explores the results from the field pilot application of the selected surfactant from their study into an ongoing polymer flood project. Changes to the injectivity of wells moving from waterflood to polymer flood, and again from polymer flood to polymer-surfactant flood, have been assessed.

Review of the initial field pilot trial data shows a positive impact of the surfactant injectivity-aid mixed within the polymer solution that was injected as part of an EOR polymer scheme. The injection data demonstrates that even at low dosage, the addition of surfactant to polymer solutions can stabilize and improve the injection process.
Lean Start-Up Procedure for Optimized Heavy Oil Well Operations
Authors: Alfoudari M. , Johar M. , Al-Naqi Y. , Khan S. B. , Pandey D. , Williams D.
Published: April 2024

The South Ratqa Heavy Oil field in Kuwait, a key initiative in the nation's thermal recovery endeavors, employs the cyclic steam stimulation (CSS) method within its challenging sandstone formations. The field's operational efficiency was hampered by the original well layout, which necessitated the dismantling of critical components such as the 4-inch production flowline, 2-inch casing gas vent line, and 2 1/16-inch wellhead sensors for maintenance and intervention access by the flushby unit (FBU). This process significantly extended downtime, contributing to a monthly production deficit of around 5,000 barrels and impacting the field's goal of 60 MBOPD.

In 2020, an initial process modification allowed the 4-inch production flowline to remain in place, reducing downtime from 10 days to 5 by avoiding its removal. Building on this improvement, a Management of Change (MOC) implemented by the Fields Development Heavy Oil Team (FDHO) in 2022 further optimized operations. The MOC enabled the immediate operation of pumps post-installation, without waiting for the reconnection of the dismantled casing gas vent line and wellhead sensors. These components could be reconnected later, aligning with the maintenance crew's schedule, thus minimizing non-productive time (NPT). Adopting this approach, rooted in lean methodology principles of efficiency and waste reduction, reduced well downtime further from 5 days to less than 24 hours, markedly improving production rates and reducing overall well downtime. This initiative, projecting annual savings of $4,900,000, has redefined operational efficiency and cost management in the South Ratqa Heavy Oil field.

The optimized flowline configuration and wellhead layout, validated through this project, will guide the design of future expansions, ensuring operational efficiency from the outset.