bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Application of Engineered Water Injection in Carbonate Reservoirs under Permeability Channeling and Gravity Underride Conditions
Authors: Adegbite Jamiu O. , Al-Shalabi Emad W. , Ghosh Bisweswar 
Published: January 2018

Abstract
This paper investigates field-scale predictions of engineered water injection (EWI) technology in the secondary and tertiary injection modes. Three synthetic 5-spot reservoir models were considered: homogeneous reservoir, heterogeneous reservoir with permeability channeling, and heterogeneous reservoir with gravity underride. The predictions were conducted by upscaling recently history matched coreflood experiments. More so, sensitivity analysis and volumetric sweep efficiency estimation for all the three reservoir models using both tracer and fractional flow methods were investigated. The results showed that the EWI in the secondary mode outperformed other injection techniques (secondary formation water injection (FWI) and tertiary EWI) in all the three reservoir models. Also, the best volumetric sweep efficiency was achieved for the homogeneous reservoir model, followed by the channeling model and then the gravity underride model. Based on the EWI technique interpreted through geochemistry, it is believed that the main reason behind the incremental oil recovery is wettability alteration. This study gives more insight into understanding EWI technology through which field-scale developments can be performed with more certainty and lower risk.
A Novel High Throughput Screening Approach for Flowback Aid Optimization
Authors: Nelson C. W. , Hilliard C. , Kalantar T. H. , Li Y. , Kuo T. , Makarychev-Mikhailov S. , Abivin P. , Prabhu R. , Khvostichenko D. 
Published: January 2018

Abstract
Flowback aid surfactants are key components for optimal water recovery after a fracturing treatment. However, comprehensive guidelines and discovery workflows for selecting an optimal flowback aid are lacking. A suite of carefully designed high-throughput screening tests coupled with industry performance tests was developed and applied to over 50 surfactants representing 12 chemical classes to create a portfolio of formation-specific flowback aids. Experiments were carried out in a two-stage approach that focuses both on intrinsic surfactant properties and on interactions with the reservoir environment. In the first stage, promising surfactant candidates were selected using high-throughput testing of surface tension, critical micelle concentration, cloud point, mineral adsorption, emulsification, and heat-aged stability. In the second stage, efficacy of surfactant candidates was assessed by testing fracturing fluid cleanup from selected shale matrices.
We observed trends in critical performance parameters with simple engineering design criteria, such as hydrophile/lipophile balance (HLB), or field conditions, such as salinity. All surfactants tested showed efficient surface tension reduction and minimal effect of salinity on surface tension. Critical micelle concentrations, however, decreased with increasing salinity, and the effect was more pronounced for surfactants with a greater HLB number. Further candidate differentiation for the optimal surfactant package was achieved by testing adsorption on shale minerals. The validity of the approach was confirmed by testing cleanup from sand and shale matrices with final product candidates.
Formation Damage Versus Chemical Performance - Important Aspects for Upscaling Scale Inhibitor Squeeze Core Floods for Carbonate Systems
Authors: Mokogwu Ike , Wilson Sam , Graham Gordon. M. 
Published: January 2018

Abstract
Core flood tests are regarded as critical to qualification and optimization of scale inhibitors (SIs) deployed in "squeeze" mode, to assess both formation damage and chemical performance. However, the different test protocols commonly adopted can have significant impact on the outcome of both these aspects. Generally, SI core flood tests are designed to obtain both pieces of information from a single flood, often compromising the optimal testing of either or leading to chemical performance aspects being favoured over formation damage orvice versa.
Recent reports have illustrated how differences in test protocols can impact chemical performance results for clastic sandstones; the work presented in this current paper examines similar challenges in tight carbonate systems, such as those exhibiting both matrix and fracture flow. It demonstrates the importance of conducting core flood tests under representative conditions for these more reactive substrates in order to qualify chemicals appropriatelysuch that upscaling to the field case can be accurately achieved.
A suite of core flood tests were conducted on outcropcarbonate cores under matrix- and fracture-dominated flow conditions (simulating both macro and micro fractures), which allowed examination of chemical behaviour under different application conditions, thus highlighting differences in chemical-retention properties and associated treatment lifetimes as well as in formation damage assessment. This paper examines results from fractured carbonate core tests, which were designed to examine SI interaction and retention where chemical transport is dominated by diffusion, and compares these withsystems where transport is dominated by advective flow in the rock matrix. The overall aim was to examine the impact that core test design can have on the results observed and to discuss the consequences of different test approaches for chemical qualification. In summary, results show that different fracture apertures and flow conditions (matrix versus fracture flow) result in significant differences in formation damage and chemical retention, illustrating the importance of correctly replicating near wellbore conditions when designing such tests.
Sand Production Caused by Water Hammer Events: Implications for Shut-In Protocols and Design of Water Injection Wells
Authors: Wang Haotian , Hwang Jongsoo , Mukul M. Sharma 
Published: January 2018

Abstract
A pressure pulse, known as a water hammer, can occur immediately after water injection wells are shut-in for emergency or operational reasons. Large pressure pulses may cause wellbore integrity problems such as sand-face failure and sand production. We propose a new workflow to simulate water hammer events, the resulting wellbore failure and sand production in water injectors. Based on the results of this workflow, recommendations are made for wellbore design and shut-in protocols for water injection wells.
The results presented in this paper, for the first time, allow us to quantitatively understand the role of well shut-downs and subsequent water hammer pressures on sand production. The failure of unconsolidated sands near the wellbore is affected by water hammer events, their amplitude, period, and attenuation. If a water hammer event occurs during shut-in of water injectors, the extent of the sand failure becomes larger and the failure zone continues to propagate along the stress concentration direction. The simulation results clearly show which parameters are important and suggest changes to well operations such as proper shut-in protocols that help to minimize the possibility of sand production. The results also suggest ways in which injectors can be designed to minimize the impact of water hammer events.
Use of Fluid Level Survey Data to Infer Near-Wellbore Conditions for Curing Lost Circulation Wells
Authors: Guo Boyun , Li J. , Cai Xiao , Zhang Xiaohui , Wang Gui 
Published: January 2018

Abstract
Lost circulation is commonly recognized as one of major drilling complications that cause low efficiency and a high cost in oil or gas well drilling. The current practice of mitigating lost circulation with lost circulation materials (LCM) is still empirical due to the lack of understanding of near-wellbore conditions. This work the first time uses pressure transient data analysis method to infer the near-wellbore conditions in lost circulation wells. The fluid level survey data can be converted to bottomhole pressure p data based on mud weight. Plot of numerical pressure derivatives data versus time data allows for identification of near-wellbore conditions and thus selection of the right type of LCM. Result of this study shows that a zero-slope trend in the plot of numerical dpdt data versus time t indicates a near wellbore condition of intersecting radial multiple fractures induced by heavy drilling fluids. Medium size LCM with a wide range of particle size distribution in a lighter drilling fluid are recommended for curring the well. A zero-slope trend in the plot of numerical tdpdt data versus time t indicates a wellbore that does not intersect any fracture. This suggests using fine size LCM with a narrow range of particle distribution in a lighter drilling fluid to cure the well. A zero-slope trend in the plot of numerical dpdt1/2 data versus time t implies a wellbore intersecting a singal fracture. This usually occurs in drilling naturally fractured carbonate reservoirs. Coarse size LCM with a wide range of particle size distribution are recommended for curring the well. A field case study illustrates that the result given by this investigation can be used for selecting LCM on the drilling site.
Scalar products and norm of Bethe vectors for integrable models based on $U_q(\widehat{\mathfrak{gl}}_{n})$
Authors: Hutsalyuk Arthur , Liashyk Andrii , Pakuliak Stanislav , Ragoucy Eric , Slavnov Nikita 
Published: January 2018

We obtain recursion formulas for the Bethe vectors of models with
periodic boundary conditions solvable by the nested algebraic Bethe
ansatz and based on the quantum affine algebra
\uqgl{m}.
We also present a sum formula for their scalar products. This formula
describes the scalar product in terms of a sum over partitions of the
Bethe parameters, whose factors are characterized by two highest
coefficients. We provide different recursions for these highest
coefficients.In addition, we show that when the Bethe vectors are on-shell, their
norm takes the form of a Gaudin determinant.
CONTENT OF PHOTOSYNTHETIC PIGMENTS IN URBAN WOOD SPECIES
Authors: Сарсацкая Анна , Sarsatskaya Anna 
Published: January 2018

<p>The study features the content of photosynthetic pigments in the leaves of <em>Larix sibirica </em>Ledeb, <em>Tilia cordata </em>Mill, <em>Populus alba </em>Ledeb <em>x Populus sowietica piramidalis </em>Jabl, <em>Acer negundo </em>Ledeb and <em>Acer tataricum </em>Ledeb in various types of urban green zones. It has been established that the pigment content is a species trait and correlatively depends on the growing conditions (remoteness from pollution sources and transport highways). In ecologically safe areas, high values of photosynthetic pigments in all species have been established, especially the indicators of the pigment amount and the ratio of chlorophyll p><p>The study involves the structure and content of the green pigment of chlorophyll in healthy and damaged leaves. In gas-resistant plant species in an urban environment, the content of a-chlorophyll and the sum of the green pigments are several times higher than in the leaves of medium-resistant species. The authors point out a change in the content of photosynthetic pigments from the concentration of acid gases in the environment and the rate of their absorption.</p>
Recovery of phenolic compounds from multi-component solution by a synthesized activated carbon using resorcinol and formaldehyde
Authors: Madureira Joana , Melo Rita , Verde Sandra Cabo , Matos Inês , Bernardo Maria , Noronha João P. , Margaça Fernanda M. A. , Fonseca Isabel M. 
Published: January 2018

AbstractThe adsorption of four phenolic compounds (gallic acid, protocatechuic acid, vanillic acid and syringic acid) is investigated using a synthesized mesoporous carbon on both single and multi-component synthetic solutions. Some correlation of the adsorption capacity of the carbon and the nature of adsorbate could be made, except for gallic acid whose concentration decrease seems to be not exclusively due to adsorption but also to polymerization reaction. In the multi-component mixture, negative effects in the adsorption capacity are observed probably due to competition for the active centers of the adsorbent surface. In desorption studies, ethanol presents better performance than water and acetonitrile. Vanillic acid is the compound with the higher adsorption and interestingly it is then possible to desorb a relatively high amount of it from the adsorbent, which may represent a possibility for a selective recovery of vanillic acid. These results present a potential way to treat the wastewater from the cork industry.
The Degree of Subjective Complaints of Students Practice in Mechanical Technology Laboratories
Authors: Widana I Ketut 
Published: January 2018

The working practice of the engineering students is part of the learning process that is irreducible and indispensable. The composition of lecturing between theoretical and practical one is 40% to 60%. With this condition, the students spend more time at the laboratory. Generally, the students perform in the laboratory work by standing position. The design of research is observational cross-sectional. The method applied is observation, interview and measuring. The subjects of research are practicing students amounting to 21 students. Referring to the analysis of statistical test or Wilcoxon signed ranks test, the difference of effect of work position is significant, namely p < 0.05 towards musculoskeletal disorders (MSDs) before and after working. The quantity of the average complaint after working is score 44.62 ± 9.47. The result of Wilcoxon signed rank test shows that there is significant different effects of standing work position, namely p < 0.05 towards fatigue generally before and after working. The degree of the working pulse is on the average of 110.78 ± 17.80 bpm (beats per minutes) which can be categorized into the medium workload. Using paired t-test, the result is p < 0.05.
Evaluasi proses bimbingan skripsi mahasiswa Universitas Negeri Yogyakarta berdasar perspektif pembelajaran orang dewasa
Authors: Sugito Sugito , Soenarto Sunaryo , Tohani Entoh 
Published: January 2018

Dalam menghadapi tantangan dan permasalahan abad kedua puluh satu ini, pendidikan tinggi memiliki peran yang sangat strategis. Mata kuliah Skripsi dapat berperan untuk mengembangkan kemampuan guna menghadapi tantangan dan masalah yang dihadapi. Penelitian ini bertujuan untuk mengevaluasi proses pembimbingan skripsi dari perspektif teori pembelajaran orang dewasa, hambatan dan upaya yang dilakukan mahasiswa dan dosen dalam proses penulisan skripsi mahasiswa Universitas Negeri Yogyakarta (UNY). Penelitian ini dilakukan dengan menggunakan pendekatan kuantitatif. Sebagai sampel adalah mahasiswa yang sudah menyelesaikan penulisan skripsi, dan dosen pembimbing. Keduanya diambil secara purposif. Jumlah responden adalah 190 orang mahasiswa dan 53 orang dosen. Data dikumpulkan dengan menggunakan angket. Data yang diperoleh melalui angket dianalisis secara deskriptif kuantitatif dengan teknik persentase. Hasil penelitian menunjukkan: (1) proses pembimbingan cenderung sudah menggunakan prinsip pembelajaran orang dewasa, yang lebih menekankan pada proses belajar mandiri; (2) hambatan yang dihadapi meliputi substansi dan metode penelitian, kemampuan bahasa asing, psikologis, dan kelengkapan sumber referensi; dan (3) upaya yang dilakukan untuk mengatasi hambatan meliputi peningkatan motivasi diri, berusaha sendiri dan pemberian kesempataan dosen pada mahasiswa untuk menyampaikan permasalahan yang dihadapi. EVALUATION OF UNDERGRADUATE THESIS MENTORING PROCESS IN UNIVERSITAS NEGERI YOGYAKARTA BASED ON ADULT LEARNING PERSPECTIVEAbstractIn facing the twenty-first century’s challenges and problems, higher education plays a very strategic role. Undergraduate thesis can contribute in developing the ability to address the challenges and problems. This study aims at evaluating the process of mentoring through the lens of adult learning theory by looking at the students’ and lecturers’ obstacles and efforts in the process of thesis writing among college students. This research was conducted using a quantitative approach with a purposively selected sample of 190 students who have completed their thesis writing, and 53 supervisors. The data were collected by questionnaire and analyzed descriptively in percentages. The results show that: (1) the process of mentoring tends to have used the principle of adult learning with more emphasis on self-directed learning; (2) the encountered obstacles include research substance and methods, foreign language abilities, psychological factors, and reference sources; and (3) some activities done to overcome the obstacles include improving self-motivation, self-effort, and providing opportunities for the students to consult their problems to the lecturer.
PENGARUH PEMBERIAN XANTHONE KULIT MANGGIS TERHADAP KADAR ASAM LAKTAT PADA AKTIVITAS FISIK SUBMASIMAL
Authors: Wibisana Muh. Isna Nurdin 
Published: January 2018

AbstrakPenelitian ini bertujuan untuk membuktikan pemberian xanthone kulit manggis dapat menurunkan kadar asam laktat pada mencit yang melakukan aktivitas fisik submaksimal. Metode penelitian adalah the randomized post-test only control group design dengan 21 sampel penelitian hewan coba mencit yang dipilih secara random dan dibagi tiga kelompok. Kelompok 1 adalah kelompok kontrol tanpa aktivitas fisik submaksimal dan tanpa pemberian xanthone, kelompok 2 adalah kelompok melakukan aktivitas fisik submaksimal dengan pemberian xanthone dan kelompok 3 adalah kelompok aktivitas fisik submaksimal tanpa pemberian xanthone. Pemberian xanthone sesaat setelah aktivitas fisik submaksimal dengan cara disonde. Aktivitas fisik submaksimal menggunakan alat treadmill khusus mencit dengan kecepatan 0,31 m/detik (80% intensitas maksimal). Pengambilan data dua jam setelah aktivitas fisik. Hasil penelitian menunjukkan kadar asam laktat mempunyai perbedaan yang signifikan pada semua kelompok (p<0,05). Uji t menunjukkan penurunan kadar asam laktat pada kelompok 2 (4,31±1,27) lebih rendah daripada kelompok 3 (6,24±1,35) dan menunjukkan hasil yang signifikan (p< 0,05). Pemberian xanthone kulit manggis dapat menurunkan kadar asam laktat darah pada mencit yang melakukan aktivitas fisik. Kata kunci : xanthone kulit manggis, kadar asam laktat, aktivitas fisik
In Vitro Antimicrobial Activity of Javanese Tamarind Leaves Infusion (Tamarindus indica Linn.) in Escherichia coli
Authors: Suryadi Caroline , Rusmana Djaja , Evacuasiany Endang 
Published: January 2018

Escherichia coli is the most common bacteria that cause diarrhea. Based on Kurniawati’s research, ethanol extract of tamarind leaves has an antimicrobial effect to Escherichia coli. This study aims to determine the antimicrobial effect using disk diffusion method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of tamarind leaves infusion against Escherichia coli. This research was done using a real laboratory experimental design with tamarind leaves infusion and Escherichia coli microbes as the research objects. Zones of inhibition were observed using disk diffusion method by putting the tamarind leaves infusion disks on Mueller-Hinton agars with Ampicillin antibiotic for comparison, followed by observing the MIC using macro broth dilution method and MBC. The result of disk diffusion showed that tamarind leaves infusion had no zone of inhibition, whereas the mean value of the zones of inhibition of ampicillin is 17.2 mm. The MIC of tamarind leaves infusion is 62.5 mg/mL. Average growth of bacteria for the MBC of tamarind leaves infusion at 125 mg/mL and 62.5 mg/mL concentration are 13 CFU/mL and >300 CFU/mL. It can be concluded that tamarind leaves infusion has antimicrobial activity effect against E.coli and that effect is bacteriostatic. Keywords: Tamarindus indica Linn, Escherichia coli, MIC, MBC
Height Estimation Based on Foot Length and Breadth in Children, Teenager, and Adult in Bandung City, Indonesia
Authors: Tanzilah Sani , Herryadi Noorman , Rusman Andri A. 
Published: January 2018

Stature estimation is important for forensic identification, particularly in dismembered body. The equation used to estimate the height of a population is not necessarily applicable to other populations (population spesific). This study was conducted to generate the linear regression equation for stature estimation based on foot length and foot breadth on the population in the city of Bandung. This cross-sectional study is conducted to 908 people, consisting of three age groups (children, adolescents, adults), in the city of Bandung. Sampling was done by multistage sampling. The stature was measured using a stadiometer SECA 213, right foot length (RFL), right foot breadth ( RFB), left foot length (LFL), and left foot breadth (LFB) were measured using sliding calipers. Data were analyzed with SPSS version 21.0 for Windows. There is correlation between height with the RFL, RFB, LFL, and LFB. In contrast to the group of teenagers and adults, there is no boys-girls difference between height, RFL, RFB, LFL, and LFB. 21 regression equation for stature estimation based on the foot size. Stature estimation can be done using the linear regression equation based on the foot length and foot breadth, according to population, gender, and age of the subject being examined. Key words: height estimation, foot length, foot breadth
Difficulty in Diagnosing Secondary Peripheral Chondrosarcoma: Radiology versus Anatomical Pathology
Authors: Ruhimat Undang , Hendarin Arie 
Published: January 2018

Chondrosarcoma is a malignant tumor derived from bone cartilage. This tumor can be either primary or secondary. Secondary chondrosarcoma has some differences compared to the primary type i.e. the incidence is rarer, the younger age group, and many are low grade. The authors report a case of a 26-year-old man came to Hasan Sadikin Hospital with a chief complaint of a lump in the right thigh with mild pain since 5 months before consulation that is increasingly enlarging. After undergoing physical and radiological examinations, the patient was diagnosed with suspect chondrosarcoma in right thigh. Histopathologic examinations were performed 2 times, one of which used ultrasound guidance, giving a diagnosis of chondroma in right thigh. However the lesion was finally treated as chondrosarcoma. We suspected that the patient was more likely to suffer from secondary peripheral chondrosarcoma originating from malignant transformation of multiple osteochondromas. As widely known, it is almost impossible to differentiate between the low grade chondrosarcoma and chondroma with full certainty and this poses a classical problem in diagnostic medicine. Case described here was an example of the difficulty in distinguishing between these two diseases. Key words: secondary chondrosarcoma, peripheral chondrosarcoma, chondrosarcoma arising in osteochondroma