bluuebunny/crossref_metadata_2025_split huggingface dataset:
Do Learning & Teaching Styles Affect Students Performance? An Empirical Study
Authors: Kamuche Felix U. 
Published: March 2016

The ways in which students normally obtain, retain, and get back information are defined as the students’ learning style. Mismatches often occur between the learning styles of students in a Basic Statistics class and the teaching style of the instructor, with adverse effects on the quality of the students’ learning and on their attitudes toward the class and the subject. The purpose of this study was to determine whether or not congruency of learning and teaching styles improve students’ performance in my Basic Statistics class.
A Modified Price-Sales Ratio: A Useful Tool For Investors?
Authors: Vruwink David R. , Quirin Jeffrey J. , O'Bryan David 
Published: March 2016

This study compares returns for stock portfolios using low price-to-earnings, price-to-book, price-to-sales, and price-to-sales ratios modified for profitability of sales and long-term debt. Non-financial companies with fiscal years ending on December 31 were included in a sample covering a 17-year period (1988-2004). The resulting sample was sub-divided into six groups by level of market capitalization. A 25 stock portfolio was then compiled for each of six valuation ratios at each level of market capitalization. An index portfolio was also computed for each level of market capitalization. First, the results of this study showed that additional expected returns based on firm size, measured by the market value of equity, is found only at the micro-cap level (less than $25 million market capitalization). The index portfolios of mini-caps ($25-100 mill.), small caps ($100-500 mill.), and mid-caps ($500-$1 bill.) did not show any additional returns in comparison to the large-cap index portfolio. Second, no "value" portfolio for mid-caps provided significant returns above the index portfolio, suggesting a much greater level of market efficiency at this level of market capitalization. Finally, the most significant findings of our study were that the portfolios constructed from low price-to-sales and modified price-to sales ratios performed as well or better than the more traditional price-to-earnings and price-to-book ratios. The price-to-sales ratio adjusted for profit margin (based on the prior three years) was statistically significant in three of six portfolios in comparison to the more traditional valuation ratios.
The JGTRRAs Tax Rate Cuts: A Financial Incentive For Tax Planning By Owner/Executives Of Small To Medium Closely Held C-Corporations
Authors: Woodruff Gregg S. 
Published: March 2016

The Jobs and Growth Tax Relief Reconciliation Act of 2003 (JGTRRA), creates a financial incentive for the owner/executives of small to medium size closely held corporations to deviate from the Pre-JGTRRA 2002 historical allocations of average taxable corporate income before owner/executive compensation to taxable salary and qualifying dividends. For purposes of comparison, this paper summarizes the 2002 tax year average taxable corporate incomes before owner/executive compensation for small to medium size closely held corporations, the 2002 average allocations to taxable salary and bonuses or qualifying dividend income and the tax consequences of those allocations. The 2002 tax year average allocations and tax consequences calculated using the JGTRRA’s tax bases and rate parameters are compared with the results of an iterative numerical search procedure that incorporates the JGTRRA’s tax base and tax rate parameters to mathematically estimate tax-minimizing allocations to owner/executive salary and bonuses versus dividends. Comparisons of the estimated tax-minimizing allocations’ 2004 (JGTTRA) tax consequences with the 2002 (using JGTTRA) tax year’s average historical allocations’ tax consequences indicate that the JGTRRA has created a financial incentive to deviate from the historical allocations to salary and bonuses versus dividends of the taxable corporate income before owner/executive compensation. One caveat or constraint to adjusting historical allocations to tax-minimizing allocations would be that the Internal Revenue Service might challenge adjusted allocations as unreasonably low salary compensation that would deprive the treasury of Social Security and Medicare taxes. Another constraint is that the iterative computations are ceteris paribus for those factors not included in the computational formula. Specifically this paper does not model for tax deferred contributions to retirement plans and does not model for the impact of the American Jobs Creation Act of 2004 and the deduction for qualified U.S. production activities.
Evaluación de definiciones de periodontitis para determinar la asociación entre enfermedad periodontal y bajo peso al nacer. Un estudio de casos y controles
Authors: Alarcón Palacios Marco A. , Proaño de Casalino Doris , Lizárraga Marroquín Christian 
Published: March 2016

Existen diversas definiciones de enfermedad periodontal para determinar datos epidemiológicos y factores de riesgo asociados a periodontitis, es así que los resultados de asociación entre periodontitis y parto pretérmino-bajo peso al nacer presentan resultados contradictorios en la literatura actual. En el presente estudio de casos y controles se evaluaron 391 madres que habían dado a luz y se les realizó el diagnóstico de su enfermedad periodontal según tres criterios de diagnóstico, 1: según el nivel de inserción clínica, 2: según criterios dados en el Workshop Europeo del 2005 y 3: según criterios de la Academia Americana de Periodoncia 2007. Los resultados muestran que no existe concordancia entre los 3 diagnósticos clínicos para la definición de caso de enfermedad periodontal, siendo los de mayor valor (kappa: 0,167) las definiciones europea y americana. Se concluye que en ninguna de las 3 definiciones se encontró relación entre parto pretérmino y bajo peso al nacer con enfermedad periodontal. Solamente la edad actúa como un factor de riesgo de presentar enfermedad periodontal con el diagnóstico de la Academia Americana de Periodoncia.
Tratamiento en sala de operaciones de dientes supernumerarios, inclusiones dentarias y quiste dentígero asociado
Authors: Aliaga Del Castillo Rosalinda , Perea Paz Miguel , De La Cruz Sedano Gabriela Silvia , Aliaga Del Castillo Arón 
Published: March 2016

Los dientes supernumerarios y las inclusiones de dientes permanentes son muy frecuentes en la infancia. Algunos dientes incluidos pueden estar asociados a la presencia de quistes dentígeros. Reportamos el caso de un paciente de sexo masculino de once años de edad con presencia de tresdientes supernumerarios en el maxilar superior, inclusión dentaria de pieza 11 e inclusión dentaria de pieza 13 con quiste dentígero asociado. El motivo de consulta fue precisamente la falta de las piezas 11 y 13 en boca. Al examen clínico intraoral presentaba: gingivitis generalizadaasociada a placa bacteriana, caries dental, ausencia clínica de piezas 11 y 13, aumento de volumen en palatino a nivel de piezas 11 y 12. Al examen radiográfico se observó que las piezas ausentes en boca se encontraban incluidas y los tres dientes supernumerarios fueron hallazgosradiográficos. El tratamiento quirúrgico se realizó bajo anestesia general. El diagnóstico temprano y tratamiento multidisciplinario fueron de vital importancia.
Toward an Alternative Bio-Based SP Flooding Technology: II. Biopolymer Screening and Evaluation
Authors: AlZahid Yara A. , AlBoqmi Abdullah M. , AlSofi Abdulkareem M. 
Published: March 2016

Abstract
Surfactant-polymer (SP) flooding is one of the most promising methods in enhanced oil recovery, especially where an existing waterflooding infrastructure is in place. Surfactants lower the interfacial tension between the injection brine and crude oil, which improves microscopic displacement efficiency by mobilizing trapped oil. In contrast, polymers increase the viscosity of injected water, which improves macroscopic sweep efficiency by stabilizing the displacing front and counteracting heterogeneity effects.
This work is part of a broader research theme in which our group is evaluating the potential of biochemicals for chemical enhanced oil recovery (CEOR). Previously, the potential of a non-ionic alkyl polglycoside biosurfactant was demonstrated for a CEOR application in a carbonate reservoir characterized by high temperature and high salinity. In this work, we evaluate the potential of several biopolymers obtained from various manufacturers. We evaluate biopolymer compatibility, viscosibility, stability, injectivity, and adsorption. We benchmark its performance against a synthetic polymer that had previously proven potent. Compatibility with the field brines (injected and connate) were investigated by observation of solution appearances. Viscosibility was investigated by measuring viscosity of solutions at various concentrations, temperatures, and shear rates. Viscosities after prolonged heating were used to investigate the stability of the biopolymers. Injectivity was studied by measuring filtration ratios. Finally, static adsorption tests using crushed core plugs were conducted, and changes in surfactant concentration, i.e., adsorption, was inferred using a total organic content analyzer.
Among the tested biopolymers, one biopolymer showed potential in terms of compatibility, stability, viscosibility, injectivity, and adsorption. Compared to the synthetic polymer, the biopolymer exhibited superb viscosibility. Concentrations around 750 ppm were sufficient to achieve the targeted viscosity at reservoir conditions. This translates to lower chemical usage and possibly improved economics. A coreflood, where the biopolymer was injected in a tertiary mode, demonstrated an additional production of around 5.2% original oil in the core (OOIC). A subsequent biopolymer/biosurfactant flood achieved an ultimate additional production of 15.5% OOIC. This performance is comparable but slightly lower (2.5% OOIC lower) than recoveries obtained with the benchmark polymer when applied as part of an SP slug. The results discussed in this paper constitute a major advancement toward developing an alternative bio-based SP flooding technology.
Studies on Surfactant-Polymer Combination Flooding Formulations for a High Salinity Reservoir
Authors: Zhu Youyi , Lei Ming 
Published: March 2016

Abstract
Alkaline-surfactant-polymer (ASP) combination flooding field tests showed that it could significantly enhance oil recovery for high water cut mature oilfields in China. The main problem in ASP flooding was the difficulties in lifting system and produced liquid treatment process due to scaling, erosion and strong emulsification caused by alkali. To avoid the side effects caused by alkali, the tendency of chemical combination flooding changes from ASP flooding to low damage combination flooding formulations such as alkali-free surfactant-polymer (SP) combination flooding. The main challenge in SP flooding is to develop surfactants with highly effective interfacial tension (IFT) reducing ability, low adsorption and good oil displacement ability especially at high salinity reservoir conditions. Yumen oilfield is a high salinity sandstone reservoir. It is a mature oilfield developed by water flooding over 60 years. A candidate EOR technique with SP chemical flooding has been proposed.
This article related the surfactant screening, IFT properties measuring, surfactant adsorption loss testing and oil displacement experiments of SP chemical flooding formulation for Yumen oilfield based on a new type surfactant alkyl polyoxypropylene ether sulfate (APES).
A series of APES surfactants were synthesized by carbon chains with different lengths and structures. The IFT measurements of both model oil/water and crude oil/formation water indicated that IFT could be significantly affected by the molecular structure of surfactants such as the length of carbon chain and propylene oxide (PO) units. The formulations of SP systems were optimized with crude oil/formation water. Ultralow IFT between crude oil and SP fluid could be obtained at the concentration range of surfactants from 0.1wt% to 0.3wt%. The dynamic adsorption experiments showed that adsorption loss of surfactant APES on the core was about 0.36 mg/g rock. Core flooding experiments of SP combination flooding showed that the incremental oil recovery for Yumen oilfield crude oil could reach to 17%-21% over water flooding.
The synthetic process of APES is simple and the surfactant is environmentally friendly. It has potential to be applied in SP chemical combination flooding to enhance oil recovery under high salinity reservoir conditions.
Studies on a Hybrid of Foam and ASP Flooding Further EOR for the Reservoir after Polymer Flooding
Authors: Zhu Youyi , Fan Jian , Hou Qingfeng 
Published: March 2016

Abstract
Most of the high permeability reservoirs in Daqing Oilfield have been conducted by water flooding and polymer flooding. The average recovery percentage of OOIP has reached to 52.6% after polymer flooding. Currently, the further development of such reservoir has become a big challenge due to both of serious heterogeneity of reservoir and highly dispersed remaining oil. The reservoir development has entered into quaternary recovery stage. Most of conventional enhanced oil recovery (EOR) techniques could not achieve the desired effects. A hybrid of foam and alkali-surfactant-polymer (ASP) flooding, as a candidate further EOR technique integrating both properties of mobility control and oil displacement has been proposed for Daqing reservoir after polymer flooding.
In this study, systematic laboratory experiments on foam formulation, ASP formulation and hybrid of foam/ASP flooding for Daqing reservoirs have been performed after polymer flooding. Several key parameters of the hybrid systems of foam/ASP flooding that influences on oil recovery efficiency were investigated and optimized. Further EOR effect of the hybrid flooding on core flood was evaluated.
The main factors that influences on oil recovery efficiency by a hybrid of foam/ASP flooding were described as below. Firstly, the properties of foam formulation and slug sizes were the key factors to ensure high performance of recovery. The foam formulation was optimized with good performances of foamability and stability. Secondly, the properties of ASP formulations and slug sizes also play important roles in EOR efficiency. The ASP formulations were optimized with ultralow interfacial tension. Concentration of chemicals and slug sizes were the main factors for oil displacement efficiency. Thirdly, a hybrid of foam and ASP flooding was optimized at the reservoirs condition. EOR effect of the hybrid flooding was studied upon three-layer positive rhythm sandpack cores flooding tests. The results indicated that hybrid flooding contributed 17%-20% of OOIP recovery as the recovery background was already 53% after polymer flooding.
The foam flooding could block preferential flow path of high permeability layer in heterogeneous reservoirs. On the other hand, ASP flooding also had higher oil displacement efficiency for the relatively low permeability layer. The hybrid of foam/ASP flooding might become a promise alternative further EOR method for Daqing reservoirs after polymer flooding.
Water Conformance Treatment using SMG Microgels: A Successful Field Case
Authors: Dupuis G. , Lesuffleur T. , Desbois M. , Bouillot J. , Zaitoun A. 
Published: March 2016

Abstract
SMG Microgels are pre-gelled polymers having a narrow size distribution and behaving like large polymer molecules whose stability is strongly enhanced by internal crosslinks. The largest species have a size of around 2 μm, which makes them suitable for Water Shutoff and Conformance Control applications in matrix reservoirs. SMG Microgels have been firstly used as water shutoff agents in gas storage wells and showed high efficiency to reduce water production while enhancing gas production. This paper reports a Conformance project which has been recently deployed in a heterogeneous sandstone reservoir. The pilot pattern consisted of one central injector, surrounded by 7 offset producers, with a spacing between 150 and 450 m. Reservoir permeability ranges between 10 and 1,000 mD with an average of 125 mD. Reservoir temperature is 48°C and salinity is 8,000 ppm TDS.
Soft SMG with size around 2 μm was chosen regarding reservoir conditions. Microgel size prevented invasion of lowest permeability zones and created flow resistance in highest permeability zones by adsorption on the rock. Microgel slug corresponded to 0.1 Pore Volume and was 10,000 m3. Microgel injection proceeded over a period of 3 months. WHP remained below max pressure authorized of 1,500 psi.
Closest producers responded within 3 months after microgel injection, with noticeable increase in oil rate along with a reduction of a few points of water cut. After one year 6 offset producers upon 7 were responding to the treatment. Three producers showed strong increase and sustained oil production, three had low response and one well lost both water and oil, showing diversion to the other wells. The trend remains steadily established in the pattern. After one year, 10,000 bbl of additional oil has been produced, along with a reduction of water production of 125,000 bbl.
Controlling Interactions of Colloidal Particles and Porous Media During Low Salinity Water Flooding and Alkaline Flooding By MgO Nanoparticles
Authors: Assef Y. , Pourafshary P. , Hejazi H. 
Published: March 2016

Abstract
Enhanced oil recovery has become a hot topic nowadays. Low-salinity water (LSW) and alkaline flooding are known as two efficient improved oil-recovery techniques to unlock residual oil. An enhanced oil recovery (EOR) project's success will be endangered when the production target is not achieved due to migration of fines, which affects reservoir permeability near the wellbore and leads to declining productivity. In this work, our experimental study aims to use nanoparticles (NPs) for the treatment of colloidal particles migration to improve the performance of the mentioned EOR methods.
In LSW and alkaline flooding methods, one critical step is the precise selection of fluids, which increases the effectiveness on these techniques. Therefore, one should choose the optimum salinity rather than the lower one to enhance the efficiency of a typical LSW project and also the optimum pH for the injected slugs rather than the higher one to improve the efficiency of an alkaline flooding project. These limitations make the design of such flooding projects very difficult and challenging. The purpose of this study is to clarify how solution conditions (pH and ionic strength) act upon surface potentials and charge distributions close to solid surfaces. Also the effects of MgO NPs on the point of zero charge (PZC) and critical salt concentration (CSC) are inspected. Zeta potential and turbidity analyses have been utilized as useful tools to examine the effect of NPs on the interactions of colloidal particles with the medium surface.
Our results illustrate that the magnitude of the repulsion forces compared to the attraction between fines particles and pore wall surfaces was considerably diminished when the surface of the glass beads was soaked with MgO NPs. The presence of MgO NPs on the bead surface significantly modifies the PZC, increasing it from 3 to around 9, which in turn justifies the retention of particles in a wide range of alkaline conditions. It was found that the MgO NP-treated medium tends to retain around 97% of the in situ fine particles under very alkaline conditions. A decrease in CSC for all divalent and monovalent salt solutions was also quantitative evidence of a striking improvement effect of these NPs. Therefore, pre-flushing of the medium with a slug of MgO nanofluid prior to alkaline flooding or LSW injection into the reservoir can serve as a promising remedy to counteract the subsequently induced migration of colloidal particles.
This technique is of great interest for application in the field, where improved oil recovery is desired; however, fines migration and subsequent formation damage should be avoided. This method minimizes the creation of damage, prevents severe plugging in the near-wellbore area, and improves communication between the wellbore and the virgin formation.
An Operational Workflow for Polymer EOR Field Trials
Authors: Geremia Giuliano , Bennetzen Martin Vad 
Published: March 2016

Abstract
Polymer flooding is the most commonly tested chemical EOR strategy worldwide. The method aims at improving the macroscopic sweep efficiency by reducing the mobility ratio, the viscous fingering and the permeability in high-perm streaks. Although a number of on-shore field trials have been performed, polymer flooding is still rarely used for offshore fields. The logistics and facility requirements make the operational design and execution more challenging in an offshore environment. The decision of conducting an offshore polymer EOR field trial must be supported by a strong technical evaluation (laboratory and simulation studies) and thorough operational field trial design that aims at targeting the different challenges to reduce risk and uncertainty and increase the likelihood of success. We present the logistical, technical and operational aspects of the design of an offshore polymer flood.
In this paper we present a procedure to minimize risk and reduce uncertainty by initial laboratory tests and continuous monitoring of key parameters when conducting the field trial. We address the logistical considerations and facility requirements related to polymer solution storage, polymer integrity, chemical additives, mixing, handling and real-time quality control. All necessary and critical parameters to be monitored are described herein. We describe the possible drag reduction induced by the polymer in the tubing, the near-wellbore shear effect on the injectivity and the pressure gauge setup essential to make a quantitative trial evaluation. We also discuss the potential impact of the polymer on the produced oil-water mixture and a way to mitigate polymer-induced emulsification via demulsifiers. Various operational conditional ‘what-if' scenarios are considered to provide a tailor made solution for each of them. Finally, we show how inter-well tracer tests can be used to evaluate polymer EOR trials wrt. macroscopic sweep improvement.
Currently, very few papers describe both operational and technical aspects, and very few papers suggest practical procedures for offshore polymer floods. With the increased focus on offshore EOR implementation due to production decline and reservoir maturation, this paper aims at providing a practical guideline and a best practice operational workflow for the design, execution and evaluation of offshore polymer EOR field tests.