bluuebunny/crossref_metadata_2025 huggingface dataset:
INVENTORY CONTROL OF DISPOSABLE MEDICAL MATERIALS AT THE BALI MANDARA EYE HOSPITAL
Authors: Yudianti Ni Wayan Yuli , Lestari Putu Nina Eka , Darma Gde Sri , Suardana IB Raka
Published: November 2021

Background: As a health service institution, hospitals have characteristics and management complexities which have an impact on their financing aspects. Controlling the supply of pharmaceutical supplies aims to create a balance between supply and demand in order to realize effective and efficient health services.Aims: This study aimed to design a method for controlling the optimal supply of disposable medical materials at the Bali Mandara Eye Hospital, Bali. Methods: This is a qualitative study based on in-depth interviews with three informants, and involving 11 doctors (users) to determine the critical value of disposable medical materials.Results: ABC analysis was used to classify all types of goods based on their importance to determine priorities based on the value of use. The budget allocation was dominated by only a small portion or only a few types of pharmaceutical supplies. The results show that there was a decrease in the total cost of inventory by 19.14% after the application of the EOQ method. The application of the reorder point (ROP) method can anticipate the occurrence of stock outs or vacancies.Conclusion: The EOQ method is more efficient than the conventional method applied at the Bali Mandara Eye Hospital Pharmacy Installation. The EOQ and ROP methods greatly affect the efficiency and effectiveness of controlling the inventory of medical disposable materials at the Bali Mandara Eye Hospital.Keywords: : inventory control, effective and efficient, medical disposable materials
PHYSIOTHERAPY SERVICE WITHOUT STANDARDIZED OPERATING PROCEDURES FROM PHYSIOTHERAPIST’S PERSPECTIVE: A CASE STUDY
Authors: Karnadipa Triana
Published: November 2021

Background: Treatment variations have been considered as a sign of an inappropriate healthcare service whether due to the underuse or the overuse of resources. To reduce these variations, establishing and implementing well-developed standardized operating procedures (SOPs) and evidence-based standardized clinical guidelines is required. A rehabilitation unit for children with disabilities in Makassar did not implement any SOPs or standardized clinical guidelines in their service and treatment. This conduct may have an adverse effect on physiotherapists’ professionalism.Aims: The study aimed to explore the possible impact of community-based rehabilitation (CBR) practice with no SOPs and evidence-based standardized clinical guidelines on the physiotherapists. Method: This study was a qualitative case study. The CBR unit was observed for 278-hours and the study conducted three semi-structured interviews. Three physiotherapists voluntarily participated in the study. Open, axial, and selective coding were conducted to encode the interview findings. The findings from observation encoded interview, field, and self-reflective notes were triangulated, analyzed thematically, and illustrated by the explorative model.Results: Working with no SOPs and guidelines was associated with variations in procedures by physiotherapists, irregularity in their treatment choices, liability feeling toward errors making, and Low self-confidence in their professionalism.Conclusion: Working without SOPs and guidelines was associated with psychological exertion of the physiotherapists. They showed uncertainty in their professional capabilities as a physiotherapist. It is recommended for YPAC Makassar city to develop SOPs and evidence-based standardized clinical guidelines for their organization.Keywords: children, community-based rehabilitation, disability, guidelines, standard-operating procedure
The Concept of Harm Reduction from Tobacco: Past, Present, Future
Authors: Babak S. L. , Gorbunova M. V. , Malyavin A. G. , Shashenkov I. V.
Published: November 2021

The concept of tobacco harm reduction (THR) is a speculative and controversial topic in the context of the international battle against the use of all types of tobacco. This concept involves providing tobacco users who are unable or unwilling to quit smoking or using other types of tobacco (snuff, chewing), with modified risk tobacco product (MRTP) for continued use. Skepticism about THR is huge and is associated with the negative experience of tobacco companies to produce cigarettes with a low content of tobacco tar/nicotine, which should have had significantly lower health risks than conventional cigarettes. Paradoxically, such an experience served as a springboard to an increase in the number of tobacco products that potentially have the properties of MRTP. Moreover, some members of the anti-smoking coalition, including WHO, consider the transition of tobacco smokers to MRTP as a strategy with great potential. However, the European Group of Experts believes that the MRTP strategy does not work and will lead to another generation of young people getting used to tobacco. In this article, we have critically analyzed the history of the past and present of tobacco products, myths and contradictions around them. We have tried to evaluate the modern concept of S THR as objectively as possible, which has a high potential for a real reduction in the number of deaths associated with smoking.
Sartre e a literatura
Authors: Pires Viana Cláudio
Published: November 2021

No ensaio Que é a literatura? publicado originalmente em 1947, Jean-Paul Sartredesenvolve os seus argumentos em resposta às duras críticas que recebia em razão do princípiodo engajamento característico de suas obras literárias. Esses críticos entendiam que Sartreutilizava a literatura como pretexto para propagar e defender suas teses políticas e filosóficas,produzindo assim um tipo de literatura engajada, distorcendo e empobrecendo o sentido nobreda arte das belles-lettres. Em resposta a essas críticas, a intenção de Sartre é fazer uma exaltaçãoda literatura, compreendendo-a como um livre desvendamento do sentido de mundo por meiode um objeto imaginário, um pacto de generosidade entre autor e leitor. Com objetivo dediscutir o sentido filosófico da literatura, este artigo se fundamenta na ontologiafenomenológica de Sartre e nos argumentos apresentados pelo autor em resposta a seus críticos,apresentando o princípio de engajamento a partir do conceito de intencionalidade daconsciência e o sentido fenomenológico da imaginação, entendendo que se trata de umadiscussão que embasa filosoficamente o entendimento do autor sobre o que é a literatura e suaimportância para a constituição da subjetividade e afirmação da liberdade.
“Amanhã pode acontecer tudo, inclusive nada”
Authors: Borges de Araújo Godinho Josué
Published: November 2021

O ensaio propõe a leitura de duas estórias de Guimarães Rosa, “A terceira margemdo rio”, de Primeiras estórias, e “Desenredo”, de Tutameia, as quais, em algum momento, serãocotejadas com Bartleby, o escrivão, de Melville. Partindo dos títulos rosianos, deduzir-se-ãoduas potências, uma neutralizadora que abdica de tudo, a outra, também neutralizadora, quequer tudo, propondo, por fim, uma ideia de leitura que se encerra nas estórias.
Poesia e filosofia
Authors: Arelli Daniel , Cei Vitor , Tessaro Pelinser André , Malloy Letícia
Published: November 2021

Daniel Arelli, poeta e filósofo de Belo Horizonte, tem se destacado no cenário daliteratura brasileira contemporânea. Em entrevista concedida aos pesquisadores do projeto“Notícia da atual literatura brasileira: entrevistas”, que consiste em mapeamento da literaturabrasileira do início do século XXI a partir da perspectiva dos próprios escritores, o autordiscorre sobre seu processo de escrita criativa, comenta a relação entre filosofia e poesia, debateo problema da filosofia brasileira, avalia a recepção de sua obra e reflete sobre outras questõeséticas e estéticas.
O Sentido de Prudência na Ética de Espinosa
Authors: Chimenez  Aviles de Lima Adriana
Published: November 2021

Resumo

Palavras-chave: Espinosa. Prudência. Regra prática. Sabedoria teórica. Vulgo.

Este artigo propõe-se a analisar o sentido de prudência na Ética de Espinosa. Será examinado o modo como o filósofo apresenta sua noção de prudência ao comunicar suas ideias tanto ao não filósofo como a um leitor mais apto à compreensão da “verdadeira filosofia”. Espinosa escreve, no Tratado Teológico Político, que, para que seja entendido e ensinar qualquer doutrina ao gênero humano, terá de adaptar seus argumentos à compreensão de todos.  Assim, sua noção de prudência é uma arte de adaptar sua comunicação ao vulgo e menciona a necessidade de demonstrar essa regra prática através da experiência. Contudo, existe um caminho almejado pelo filósofo que busca a conciliação de uma sabedoria teórica que pretende alcançar uma “prudência mais alta”. Este artigo buscará indicar alguns conceitos e considerações presentes na obra de Espinosa em que sua noção de prudência opera e tem suas bases firmadas no campo do conhecimento e da razão, assim como no campo dos afetos e das relações afetivas. A Parte V da Ética considera em seu primeiro axioma o lugar de mudanças que ocorrem em um mesmo sujeito como uma prática inseparável daquilo que Espinosa designa como prudência. Sem a intenção de esgotar a apresentação desse tema no pensamento do filósofo, essa compreensão será o ponto de partida deste trabalho ainda em andamento, para a análise e reflexão da noção e do sentido de prudência espinosana.
Kant e a estética
Authors: Sena Daniel Richardson de Carvalho , Silva Victor Leandro
Published: November 2021

Resumo: Esse texto visa passar em revista aspectos do pensamento estético de Immanuel Kant, bem como debater as formas pelas quais suas teorias acerca do juízo influenciam as suas mais agudas concepções acerca do processo formativo dos sujeitos e contribuem para sua compreensão de mundo. Kant empreendeu uma profunda análise a respeito das questões relativas aos juízos estéticos, a partir dos conceitos de belo e de sublime. Assim, o que se procura delinear aqui é o percurso realizado pelo filósofo na abordagem do referido tema, ao passo que analisará as relações existentes entre sua teoria da arte e a questão do esclarecimento, eixo central do projeto filosófico kantiano.

Palavras-chave: estética, belo, sublime, arte.
Ontologia da relação em A ideologia alemã de Karl Marx
Authors: Alves de Souza Klédson Tiago , Araújo de Medeiros Emerson
Published: November 2021

Neste artigo buscamos refletir acerca de uma ontologia da relação no pensamento de Karl Marx. Tomamos como ponto de partida a obra A Ideologia Alemã. Na filosofia marxiana, a ontologia nasce do pensamento cotidiano, isto é, o sujeito com suas relações passa a primeiro plano na história. Aqui o homem é visto como atividade sensível, e isso significa vê-lo como mescla de teoria e práxis, tendo a vida real, ou a prática, como fundamento constitutivo da teoria, e não o inverso.
Near Chromosome-Level Genome Assembly and Annotation of Rhodotorula babjevae Strains Reveals High Intraspecific Divergence
Authors: Martin-Hernandez Giselle C. , Müller Bettina , Brandt Christian , Hölzer Martin , Viehweger Adrian , Passoth Volkmar
Published: November 2021

The genus Rhodotorula includes basidiomycetous oleaginous yeast species. R. babjevae can produce compounds of biotechnological interest such as lipids, carotenoids and biosurfactants from low value substrates such as lignocellulose hydrolysate. High-quality genome assemblies are needed to develop genetic tools and to understand fungal evolution and genetics. Here, we combined short- and long-read sequencing to resolve the genomes of two R. babjevae strains, CBS 7808 (type strain) and DBVPG 8058 at chromosomal level. Both genomes have a size of 21 Mbp and a GC content of 68.2%. Allele frequency analysis indicated tetraploidy in both strains. They harbor 21 putative chromosomes with sizes ranging from 0.4 to 2.4 Mb. In both assemblies, the mitochondrial genome was recovered in a single contig, which shared 97% pairwise identity. The pairwise identity between the majority of chromosomes ranges from 82% to 87%. We found indications for strain-specific extrachromosomal endogenous DNA. 7,591 protein-coding genes and 7,607 associated transcripts were annotated in CBS 7808 and 7,481 protein-coding genes and 7,516 associated transcripts in DBVPG 8058. CBS 7808 has accumulated a higher number of tandem duplications than DBVPG 8058. We identified large translocation events between putative chromosomes and a high genetic divergence between the two strains.
Implication, Equivalence, and Negation
Authors: Arnon Avron
Published: November 2021

A system $HCL_{\overset{\neg}{\leftrightarrow}}$ in the language of {$ \neg, \leftrightarrow $} is obtained by adding a single negation-less axiom schema to $HLL_{\overset{\neg}{\leftrightarrow}}$ (the standard Hilbert-type system for multiplicative linear logic without propositional constants), and changing $ \rightarrow $ to $\leftrightarrow$. $HCL_{\overset{\neg}{\leftrightarrow}}$ is weakly, but not strongly, sound and complete for ${\bf  CL}_{\overset{\neg}{\leftrightarrow}}$ (the {$ \neg,\leftrightarrow$} – fragment of classical logic). By adding the Ex Falso rule to $HCL_{\overset{\neg}{\leftrightarrow}}$ we get a system with is strongly sound and complete for ${\bf CL}_ {\overset{\neg}{\leftrightarrow}}$ . It is shown that the use of a new rule cannot be replaced by the addition of axiom schemas. A simple semantics for which $HCL_{\overset{\neg}{\leftrightarrow}}$ itself is strongly sound and complete is given. It is also shown that  $L_{HCL}$$_{\overset{\neg}{\leftrightarrow}}$ , the logic induced by $HCL_{\overset{\neg}{\leftrightarrow}}$ , has a single non-trivial proper axiomatic extension, that this extension and ${\bf  CL}_{\overset{\neg}{\leftrightarrow}}$ are the only proper extensions in the language of { $\neg$, $\leftrightarrow$ } of $ {\bf  L}_{HCL}$$_{\overset{\neg}{\leftrightarrow}}$ , and that $ {\bf  L}_{HCL}$$_{\overset{\neg}{\leftrightarrow}}$ and its single axiomatic extension are the only logics in {$ \neg, \leftrightarrow$ } which have a connective with the relevant deduction property, but are not equivalent $\neg$ to an axiomatic extension of ${\bf R}_{\overset{\neg}{\leftrightarrow}}$ (the intensional fragment of the relevant logic ${\bf R}$). Finally, we discuss the question whether $ {\bf  L}_{HCL}$$_{\overset{\neg}{\leftrightarrow}}$ can be taken as a paraconsistent logic.
Scale Control for Long Term Well and Facility Preservation
Authors: Yan Chao , Wang Wei , Wei Wei
Published: November 2021

Oilfield scale and corrosion at oil and gas wells and topside facilities are well known problems. There are many studies towards the control and mitigation of scaling risk during production. However, there has been limited research conducted to investigate the effectiveness of scale control approaches for the preservation of wells and facility during a potential long term shut-in period, which could last more than 6 months. Due to low oil price and harsh economic environment, the need to shut-in wells and facilities can become necessary for operations. Understanding of scale control for a long term period is important to ensure both subsurface and surface production integrity during the shut-in period. The right strategy and treatment approaches in scale management will reduce reservoir and facility damage as well as the resulting cost for mitigation.

In this paper, we will review and assess the scale risk for different scenarios for operation shut-in periods and utilize laboratory study to improve the understanding of long-term impact and identify appropriate mitigation strategy. Simulated brine compositions from both conventional and unconventional fields are tested. Commercially available scale inhibitors are used for testing. Various conditions including temperature (131-171 °F), saturation index (1.28-1.73), pH (7.04-8.03) and ratio of scaling ions are evaluated. The tested inhibitor dosage range was 0-300 mg/L. Inhibitor-brine incompatibility was also investigated. Sulfate and carbonate scales such as barium sulfate, strontium sulfate and calcium carbonate are studied as example. This paper will provide an important guidance for the management of well shut- in scenarios for the industry, for both conventional and unconventional fields.

Performance of two scale inhibitors for same water composition are demonstrated. The efficiency of scale inhibitor #2 is lower than that of inhibitor #1. A linear correlation is observed for long term scale inhibitor performance in this case. Protection time is thus predicted from data collected from the first 8-week experiments. The predicted protection time at 250 mg/L of inhibitor A and B is 100 weeks and 16 weeks respectively. The actual protection time will be compared to the predicted value. The inhibitor-rock interaction has also been preliminarily studied. The effects of inhibitor adsorption onto formation rock should be considered for chemical treatment design and performance/dosage optimization.

This study provides novel information of scale control in a much longer time frame (up to 6 months). Various parameters may have effects on their long term control. Results will benefit the chemical selection and evaluation for long term well shut-in scenario. In addition, brine-inhibitor compatibility is evaluated simultaneously.
Geochemical Modeling of Petrophysical Alteration Effect on CO2 Injectivity in Carbonate Rocks
Authors: Bordeaux Rego Fabio , Tavassoli Shayan , Eltahan Esmail , Sepehrnoori Kamy
Published: November 2021

Carbon dioxide injection into sedimentary formations has been widely used in enhanced oil recovery (EOR) and geological-storage projects. Several field cases have shown an increase in water injectivity during CO2 Water-Alternating-Gas (WAG) projects. Although there is consensus that the rock-fluid interaction is the main mechanism, modeling this process is still challenging. Our main goal is to validate a physically based model on experimental observations and use the validated model to predict CO2 injectivity alteration based on geochemical reactions in carbonate rocks.

In this paper, we present a new method for CO2 reactive transport in porous media and its impact on injectivity. We hypothesize that if CO2 solubilizes in the connate water, then it induces a shift in chemical equilibrium that stimulates mineral dissolution. Consequently, porosity and permeability will increase, and cause alterations to well injectivity. We develop a predictive model to capture this phenomenon and validate the model against available data in the literature. We use UTCOMP-IPhreeqc, which is a fully coupled fluid-flow and geochemical simulator to account for rock/hydrocarbon/water interactions. In addition, we perform several experiments to test CO2/water slug sizes, mineralogy assembly, injected brine composition, and gravity segregation combined with the effect of heterogeneity.

Coreflood simulations using chemical equilibrium and kinetics indicate mineral dissolution at reservoir conditions. The results suggest that the intensity of rock dissolution depends on formation mineralogy and brine composition as carbonate systems work as buffers. Additionally, we show that prolonged CO2 and brine injection induces petrophysical alteration close to the injection region. Our field-scale heterogeneous reservoir simulations show that permeability alteration calculated based on Carman-Kozeny correlation and wormhole formulation had the same results. Furthermore, we observed that water injectivity increased by almost 20% during subsequent cycles of CO2-WAG. This finding is also supported by the Pre-Salt carbonate field data available in the literature. In the case of continuous CO2 injection, the carbonate dissolution was considerably less severe in comparison with WAG cases, but injectivity increased due to unfavorable CO2 mobility. With the inclusion of gravity segregation, we report that the injectivity doubles in magnitude. The simulations show more extensive dissolution at the upper layers of the reservoir, suggesting that preferential paths are the main cause of this phenomenon. The ideas presented in this paper can be utilized to improve history-matching of production data and consequently reduce the uncertainty inherent to CO2-EOR and carbon sequestration projects.
Laboratory and Pilot Tests of Enhanced Oil Recovery through Wettability Alteration by Diluted Microemulsions
Authors: Zhao Xurong , Liang Tianbo , Zan Jingge , Zhang Mengchuan , Zhou Fujian , Chen Zhiming
Published: November 2021

Replacing oil from small pores of tight oil-wet rocks relies on altering the rock wettability with the injected fracturing fluid. Among different types of wettability-alteration surfactants, the liquid nanofluid has less adsorption loss during transport in the porous media, and can efficiently alter the rock wettability; meanwhile, it can also maintain a certain oil-water interfacial tension driving the water imbibition. In the previous study, the main properties of a Nonionic nanofluid-diluted microemulsion (DME) were evaluated, and the dispersion coefficient and adsorption rate of DME in tight rock under different conditions were quantified.

In this study, to more intuitively show the change of wettability of DME to oil-wet rocks in the process of core flooding experiments and the changes of the water invasion front, CT is used to carry out on-line core flooding experiments, scan and calculate the water saturation in time, and compare it with the pressure drop in this process. Besides, the heterogeneity of rock samples is quantified in this paper. The results show that when the DME is used as the fracturing fluid additive, fingering of the water phase is observed at the beginning of the invasion; compared with brine, the fracturing fluid with DME has deeper invasion depth at the same time; the water invasion front gradually becomes uniform when the DME alters the rock wettability and triggers the imbibition; for tight rocks, DME can enter deeper pores and replace more oil because of its dominance. Finally, the selected nanofluids of DME were tested in two horizontal wells in the field, and their flowback fluids were collected and analyzed. The results show that the average droplet size of the flowback fluids in the wells using DME decreases with production time, and the altered wetting ability gradually returns to the level of the injected fracturing fluid. It can be confirmed that DME can migrate within the tight rock, make the rock surface more water-wet and enhance the imbibition capacity of the fracturing fluid, to reduce the reservoir pressure decline rate and increase production.
Adaptation of Test Methodology and the Evolution of a Demulsifier Formulation for a Heavy Oil Start-Up
Authors: White A. , Miller R. , Bellu E. , Wylde J. J.
Published: November 2021

Objectives/Scope

Selection of "first fill" demulsifiers for new, undeveloped, oil fields has significant limitations, typically relying on data from test work with synthetic emulsion created in a laboratory using highly contaminated drilling samples of crude oil. Additional separation challenges related to offshore production of high viscosity, low API crude oil, from a low temperature reservoir results in a low probability of success in selecting a suitable first fill demulsifier using the traditional bottle test alone.

Methods, Procedures, Process

To give improved speed of oil/water separation, water quality, interface quality and top oil dehydration, samples of chemical free oil and produced water were used to screen alternative existing products against the base case demulsifier via bottle testing. The emulsions were created using a high shear stirrer to mimic the system conditions of the wells coming online and water droplet size within the emulsion was determined via cross polarizing thermal microscopy. For the purposes of these tests, demulsifier performance was ranked on speed and completeness of separation, interface quality, water quality and grind out (BS&W) characteristics.

Results, Observations, Conclusions

Several differences were observed between the initial and subsequent test work. The low shear emulsion created in the early work was found to be very unstable, separating easily with no residual emulsion in the crude oil. The emulsion created under high shear conditions gave a much closer correlation in terms of water droplet distribution to that measured during the field test and resulted in a much more stable emulsion that was more difficult to separate and typically left unresolved emulsion in the oil after the bulk of the water had separated. Whilst the original demulsifier recommendation was still able to facilitate separation it was found that it was no longer the optimum product, with other previously disregarded products able to provide a higher level of performance on the high shear emulsion.

Novel/Additive Information

This paper demonstrates that a higher level of performance was achieved with an enhanced screening process, namely through high shear stirring and confirmation of water droplet size within the emulsion. When added to the standard bottle testing conditions, the development of demulsifiers can better ensure an optimum result, fit for purpose for the application.
A Supramolecular Thickener Based on Non-Covalent Enhancement Mechanism
Authors: Ma Yingxian , Huang Liqiang , Zhu Zhi , Du Yurou , Lai Jie , Guo Jianchun
Published: November 2021

Inspired by non-covalent enhancement mechanism, we introduced glycinamide-conjugated monomer (NAGA) with dual-amide in one side group to amplify the hydrogen bonding interactions. Via one-step free radical polymerization strategy, we prepared a type of supramolecular thickener based on binary polymer. With NMR, FT-IR and SEM results’ help, we determined that PNAGA-AM system had unique bis-amide structure of glycinamide-conjugated monomer. As a result, the synthesized polymer could generate a much denser structure based on the high-ordered multiple hydrogen bonding with lower molecular weight (Mn = 778,400 g/mol), increasing the strength and stability of the chains. PNAGA-AM system had good thickening and temperature-resistant properties. The thickener viscosity of PNAGA-AM(3.0wt%) had twice as much as that of corresponding PAM system. And the viscosity of the 1.5 wt% solution prepared by PNAGA-AM could maintain 74 mPa·s at 150 °C. Meanwhile, the supramolecular system showed excellent salt resistance and self-healing performance with the non-covalent/hydrogen bonding interactions and physical entanglements. The viscosity of the PNAGA-AM system did not drop but increase in high salinity (≤ 300,000 mg/L salinity), and the maximum viscosity could increase nearly 44 % compared with the initial situation. In addition, the self-healing efficiency was over 100 % at 120 °C. Overall, the fracturing fluid system based on PNAGA-AM system could maintain outstanding rheological properties under extreme conditions and showed brilliant recovery performance, to make up the disadvantages of currently used fracturing fluid. It is expected to mitigate potential fluid issues caused by low water quality, harsh downhole temperatures and high-speed shearing.
Evaluation of Lignosulfonate Based Retarders for Thickening Time as a Function of Dosage and Temperature
Authors: Montgomery Justin , McNally Timothy , Hunger Jay , Subramanian Sreedhar
Published: November 2021

The retardation of class H Portland cement using lignosulfonates was investigated in the temperature range between 54°C and 153°C. Lignosulfonates with varying extent of modification was used in the study, and the optimum retarder dosage and temperature range to achieve desired thickening time was identified for different lignosulfonate types (non-modified, modified and highly modified). In general, a linear thickening response was observed at low retarder dosage, while a near exponential increase in thickening time response was observed at higher dosages.

Defining the retarder dosage temperature relationship is essential for proper cement slurry design for securing desired placement of cement slurry. A significant finding is that the thickening time responses trend from near linear at low dosages, transitioning to near exponential at higher dosages. The observed results varied depending on the extent of modification performed on the lignosulfonate retarder.

Pure lignosulfonate retarders produce optimal dosage response from 54°C to 97°C. Modified retarders work best in the range of 97°C to 118°C. While highly modified retarders perform best in the range of 118°C to 153°C. Defining the retarder dosage temperature relationship is essential for proper cement slurry design for securing desired placement of cement slurry.
Theories and Work Towards Understanding a Mysterious Case of Severe Bakken Brine Incompatibility
Authors: Spicka Kevin , Holding Eagle Lisa , Longie Chris , Dahlgren Kyle , Gerbino AJ , Koerner Alex , Loder Greg
Published: November 2021

The Bakken formation is well known for producing brine very high in total dissolved solids (TDS). Halite, calcium carbonate, and barium sulfate scales all can pose substantial production challenges. Trademarks of Bakken produced brine include elevated concentrations of sodium (>90,000 mg/L), chloride (>200,000 mg/L), and calcium (>30,000 mg/L), contrasted against low concentration of bicarbonate (50-500 mg/L).

In the past 3 years, operators have experienced unexpected instances of severe calcium carbonate scale on surface where produced fluids from the production tubing commingled with the gas produced up the casing. Initially treated as one-off scale deposits despite the application of scale inhibitor, acid remediation jobs or surface line replacement were typical solutions. As time has passed, this issue has become more and more prevalent across the Bakken. Investigation of this surface issue discovered a most unexpected culprit: a low TDS, high alkalinity brine (up to 92,000 mg/L alkalinity measured to date) produced up the casing with the gas. When mixing with the high calcium brine typically produced in the Bakken, the resulting incompatibility posed remarkable scale control challenges.

The uniqueness of this challenge required thorough analytical work to confirm the species and concentrations of the dissolved ions in the brine produced with the gas. Scale control products were tested to evaluate their abilities and limitations regarding adequate control of this massive incompatibility. The theory that corrosion contributed to this situation has been supported by a unique modelling approach. Once corrosion was identified as the likely source of the high alkalinity brine, corrosion programs were instituted to help address the surface scaling. This paper highlights the evaluations conducted to fully grasp the severity of the incompatibility, the theories put forth to date, work conducted to try to replicate the phenomena in the lab and in models, and chemical programs used in the field to address corrosion and scale.

While not known to exist in other oilfield basins, conventional or unconventional, this discovery may have implications for the broader industry if similar situations occur. The possible explanations for why this may be happening may have implications for scale control, asset integrity, and potentially even the methods by which wells are produced.
Online Cleaning of Carbonate Deposits. The Potential and Limitations of a Novel Cleaning Method
Authors: Jordan Myles Martin , Sutherland Louise , Johnston Clare Jennifer
Published: November 2021

The formation of calcium carbonate scale within produced brine as it passes through topside heaters is a very common flow assurance challenge. Normally this scale risk is predicted and chemically controlled via scale inhibitors deployed upstream of the point of brine supersaturation. In some operations chemical application is not fully effective due to under treating of the chemical or carbonate from the reservoir (fines) builds up within the heaters. In cases of reduced fluid throughput cleaning of the inorganic scale is required. The most common method of cleaning is to take the heater offline and batch clean with acids (mineral or organic) to remove the deposits.

This paper outlines an investigation into the performance of conventional batch cleaning vs a more novel application method of online cleaning the heater while operating with application of organic acid into the produced fluid upstream of the heaters. The online cleaning process was evaluated via laboratory tests where packed column of field scale were flushed with organic acid within the produced water, and for comparison mineral acid, to understand the potential for online cleaning vs batch cleaning and what factors influenced the effectiveness of these application methods. Factors evaluated included flow rate/contact time, acid strength and acid type. During these online cleaning tests, the effluent of each column was evaluated for pH and finally weight loss at the end of the tests. The online cleaning results were compared to conventional batch cleaning assessment of the same scale samples via static bottle tests

The observations from the tests show that online cleaning using both organic and mineral acids result in the development of preferential flow paths within the scale packed columns that reduces the effectiveness of the cleaning chemicals. Improvements to the cleaning program were investigated such as the scale thickness when cleaning is first started to improve cleaning performance and fluid flow rate, increased acid concentration and liquid to solid ratio changes. Field application data from the initial cleaning programs and improvements to the cleaning programs will be shared as part of this publication

The factors that need to be assessed to determine if this method is suitable for a specific process system and likelihood of effective scale removal are presented. This method does present the possibility for some production systems that cleaning of carbonate scale can be carried out without the need to take the heater offline for chemical batch or mechanical cleaning.
Effective Treatment of Humic Acid Foulants in SAGD Produced Water
Authors: Li Chunli , Yue Zhiwei David , Tian Xiaohong , Hazlewood John
Published: November 2021

Humic acids, one major type of organic foulants in steam assisted gravity drainage (SAGD) produced water, can precipitate on surface and downhole equipment in SAGD facilities, resulting in high cleaning costs, potential equipment damage and decrease of injectivity of disposal wells. In this paper, a cost-effective chemical solution is presented where an alcohol ethoxylate surfactant/chelating agent package can efficiently disperse the organic fouling molecules in SAGD produced water; therefore, the approach is expected to significantly mitigate the humic acid related fouling issues in the SAGD system.

In this study, a variety of commercially available surfactant products were evaluated for their aids in well injectivity on humic acid molecules in the freshly obtained SAGD produced water. The lab testing filtration apparatus was specially designed to simulate the sandstone formation geology of SAGD disposal wells. An "efficiency factor" was defined to grade the dispersing performance of the surfactant and/or surfactant/chelating agent package in the lab filtration tests. The efficiency factor provides a reasonable estimation regarding how well the chemical can reduce the plugging risk in a disposal well as compared to the untreated produced water.

Among all the surfactant products tested, an alcohol ethoxylate surfactant with the appropriate molecular structure shows distinguished dispersing performance on humic acids in SAGD produced water. However, the surfactant alone was found inconsistent in the dispersing performance when different batches of the produced water were involved. Inclusion of the specific metal chelating agents to the above surfactant formulation improved the dispersing performance consistency. The chelator molecules presumably help destroy the intermolecular bridges among humic acid molecules in the SAGD produced water; thereby, increasing the dispersing effectiveness of the alcohol ethyoxylate surfactants. Tests show that the efficiency factor of the surfactant/chelating agent package is higher than 8, which implies that the formulation could lead to eight times extension of the interval between workovers on SAGD disposal wells, a significant reduction for the operational downtime and costs.

This study presented a cost-effective chemical solution to help disperse the humic acid molecules in SAGD produced water, which can help significantly reduce the fouling risk caused by organic foulants, improve injectivity and extend the intervals between workovers of SAGD disposal wells.
Novel Mineral Scale Deposition Model Under Different Flow Conditions with or Without Scale Inhibitors
Authors: Dai Zhaoyi Joey , Kan Amy , Lu Yi-Tsung Alex , Leschied Cianna , Zhao Yue , Dai Chong , Wang Xin , Paudyal Samridhdi , Ko Saebom , Tomson Mason
Published: November 2021

Mineral scale formation causes billions of dollars’ loss every year due to production losses and facility damages in the oil and gas industry. Accurate predictions of when, where, how much, and how fast scale will deposit in the production system and how much scale inhibitor is needed are critical for scale management. Unfortunately, there is not a sophisticated scale deposition model available, potentially due to the challenges below. First, an accurate thermodynamic model is not widely available to predict scale potential at extensive ranges of temperature, pressure, and brine compositions occurring in the oilfield. Second, due to the complex oilfield operation conditions with large variations of water, oil and gas flow rates, tubing size, surface roughness, etc., wide ranges of flow patterns and regimes can occur in the field and need to be covered in the deposition model. Third, how scale inhibitors impact the mineral deposition process is not fully understood. The objective of this study is to overcome these challenges and develop a model to predict mineral deposition at different flow conditions with or without scale inhibitors. Specifically, after decades of efforts, our group has developed one of the most accurate and widely used thermodynamic model, which was adopted in this new deposition model to predict scale potential up to 250 °C, 1,500 bars, and 6 mol/kg H2O ionic strength. In addition, the mass transfer coefficients were simulated from laminar (Re < 2300) to turbulent (Re > 3,100) flow regimes, as well as the transitional flow regimes (2300 < Re < 3,100) which occur occasionally in the oilfield using sophisticated flow dynamics models. More importantly, the new deposition model also incorporates the impacts of scale inhibitors on scale deposition which was tested and quantified with Langmuir-type kink site adsorption isotherm. The minimum inhibitor dosage required can be predicted at required protection time or maximum deposition thickness rate. This model also includes the impacts of entry-region flow regime in laminar flow, surface roughness, and laminar sublayer stability under turbulent flow. The new mineral scale deposition model was validated by our laminar tubing flow deposition experiments for barite and calcite with or without scale inhibitors and laminar-to-turbulent flow experiments in literature. The good match between experimental result and model predictions show the validity of our new model. This new mineral scale deposition model is the first sophisticated model available in the oil and gas industry that can predict mineral scale deposition in the complex oilfield conditions with and without scale inhibitors. This new mineral scale deposition model will be a useful and practical tool for oilfield scale control.
Development of Dynamic Tube Blocking Test Method to Study Halite Scale Deposition and Inhibition
Authors: Paudyal Samridhdi , Ruan Gedeng , Lee Ji-young , Wang Xin , Lu Alex , Dai Zhaoyi , Dai Chong , Ko Saebom , Zhao Yue , Yao Xuanzhu , Leschied Cianna
Published: November 2021

Halite scaling has been observed in the oil/gas field with high TDS and low water cut. Due to its higher solubility, slight changes in temperature (T) and pressure (P) and evaporative effect could yield a large amount of scale, causing significant operational problems. Accurate prediction and control of halite scaling in the oil and gas production system have been a challenge. Therefore, this study aims to shed light on the prediction of halite scale formation, deposition behavior, and inhibition at close to oil field conditions. We have designed and developed a dynamic scale loop (DSL) test methodology that can be used at various T and P. The test method utilizes a change in temperature (ΔT) as a driving force to create halite supersaturation and follow with the scale precipitation/deposition. The tube blocking experiments suggest that the tube blockage can be caused by bulk precipitation and or deposition of halite precipitate. SEM analysis of the tube cross-sections indicated that tube blockage, presumably by bulk precipitation, could be seen at the beginning of the reaction tube, but deposition was observed towards the exit end of the tube. Similarly, various experimentation to simulate the water dilution at constant pressure and ΔT were conducted. The effect of the addition of water to prevent halite deposition was analyzed computationally by using ScaleSoftPitzer (SSP) software. Brine compatibility of several inhibitors were tested via bottle tests and autoclave tests and qualified inhibitors were tested in the tube blocking experiments to identify the performance of the inhibitor to treat the halite precipitation at high temperature and pressure. Overall, a robust test method was designed and developed for halite scaling under high temperature and pressure that can simulate the oil and gas production in the field.
New Kinetic Turbidity Test Method and Prediction Model for Calcite Inhibition
Authors: Dai Chong , Dai Zhaoyi , Paudyal Samiridhdi , Ko Saebom , Zhao Yue , Wang Xin , Yao Xuanzhu , Kan Amy , Tomson Mason
Published: November 2021

Calcite, as one of the most common scales in oilfield can be inhibited by common scale inhibitors. The measurement of calcite nucleation and inhibition is a challenge, because of the difficulty to control pH as a result of CO2 partitioning in and out of the aqueous phase. A new kinetic turbidity test method was developed so that the partial pressure of CO2, pH, and SI can be precisely controlled. Calcite nucleation and inhibition batch tests were conducted under various conditions (SI = 0.24-2.41, T = 4-175 °C, and pH = 5.5-7.5) in the presence of common phosphonate and polymeric inhibitors. Based on experimental results, calcite nucleation and inhibition semi-empirical models are proposed, and the logarithm of the predicted induction time is in good agreement with the measured induction time. The models are also validated with laboratory and field observations. Furthermore, a new BCC CSTR Inhibition (BCIn) test method that applied the Continuous Stirred Tank Reactor (CSTR) theory has been developed, for the first time. This BCIn method was used for calcite inhibitor screening tests and minimum inhibitor concentration (MIC) estimation. By only running one experiment (< 1 hour) for each inhibitor, BCIn method selected the effective inhibitors among 18 common inhibitors under the conditions of SI = 1.23 at 90 °C and pH = 6. It was also found that the critical concentration (Ccrit) from BCIn method has a correlation with the MIC from batch tests. This study provided a simple and reliable solution for conducting calcite scale inhibition tests in an efficient and low-cost way. Furthermore, the newly developed prediction models can be used as guidance for laboratory tests and field applications, potentially saving enormous amounts of time and money.
The World Bank in Asia: An assessment of COVID-19-related investments through a care lens. Care-responsive investments and development finance
Authors: Chauhan Dharmistha , Bist Joshi Swapna
Published: November 2021

International financial institutions (IFIs) and multilateral development banks have been playing a vital role in the response, recovery and ‘build back anew’ agenda from the COVID-19 pandemic. This is especially true of the World Bank Group (WBG), given its high volumes of committed investments across sectors, especially in low-income and vulnerable countries. This report presents, through case studies, how care-responsive the World Bank’s COVID-19-related investments have been in four member countries: Bangladesh, Cambodia, Nepal and the Philippines. It does so by using the Care Principles and Care-Responsive Barometer for IFIs to assess the nature of the WBG’s post-COVID recovery investments in these select countries, and by building evidence through a gender- and care-responsive budget review. The foundation for care inclusion has already been laid in WBG policy. The report uses this as an entry point to urge it to bring women’s unpaid, underpaid and paid work to the centre of the IFI agenda in order to move towards rebuilding a more gender-just and equal future.
Understanding the photon-photon resonance of DBR lasers using mode expansion method
Authors: Chen Da , Liu Ye , Yu Yonglin
Published: November 2021

A theoretical model based on the mode expansion of the traveling wave equations is developed to investigate the mode interaction processes behind the photon-photon resonance (PPR) effect in distributed Bragg reflector (DBR) lasers. With dual-mode rate equations, strength of mode interactions is characterized by the cross power and the coupling factors, which arise from the non-orthogonality of the main mode and the PPR mode. Small signal analysis and large-signal dynamics are performed, and results indicate that the cross power is a key contributor to the PPR effect.
Effects of levamisole on haematological and oxidative stress parameters in packed donkeys
Authors: Okaiyeto Babatunde Folayemi , Sackey Anthony Kojo , Mohammed Abdullahi Koko , Aluwong Tangang
Published: November 2021

Stress can be caused by psychological, physiological, environmental and physical factors. Strenuous exercise like packing in donkeys modifies haematologic parameters. The aim of the study was to investigate the ameliorative effects of levamisole on stress, in packed donkeys. 15 adult male donkeys aged between 4 – 5 years were selected for this study, divided into groups (A, B, C) of five donkeys each: Groups A and B donkeys were the apparently healthy group; while Group C donkeys were naturally infected with Strongyle spp. All the donkeys participated in load carrying (packing) of 40 kg for 10 km. Groups B and C were treated with levamisole at 7.5 mg/kg, while Group A received no treatment prior to packing. Blood was collected from all the groups for haemogram and oxidative stress biomarker analyses. No significant effect (P > 0.05) was observed between groups: A, B and C for: respiratory rate, pulse rate and rectal temperature; haemogram, and activities of malondialdehyde concentration, superoxide dismutase and catalase. Erythrocyte membranes were osmotically stable at 0.5% NaCl in the treated group in comparison to the controls. Packing of donkeys for 10 km did not induce significant changes in vital parameters, haemogram and biomarkers of oxidative stress, but levamisole improved erythrocyte membrane stability. It was concluded that packing for 10 km did not induce any significant changes in blood cellular components and biomarker of oxidative stress, but levamisole improved erythrocyte membrane stability.