bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Universal Equation to Calculate Shale Volume for Shaly-Sands and Carbonate Reservoirs
Authors: David Soto O. , Rodolfo Soto B. , Jonathan Soto O. , Pasquel Oliver , Arteaga Duarry 
Published: November 2015

Abstract
It is common to use the standard gamma ray log (SGR) or the total contribution from all three elements— uranium (U), potassium (K), thorium (Th)] as an indicator of shale content. The linear IGR shaliness indicator model over-estimates the shale volume. The nonlinear models have been developed for specific geographic areas or formation ages. All non-linear relationships are more optimistic in that they produce a shale volume value lower than that from the linear equation. On the other hand, the presence of highly-radioactive black organic material in carbonate or unconventional reservoirs "gas/oil shale", overestimates the shale volume. In all cases, an accurate determination of shale volume impacts in the calculation of formation porosity and water saturation and therefore affects the original oil in place (OOIP) and reserves.
The question from engineers and geoscientists: which is the best model to be used? We have found that the sigmoidal function can be used for any kind of reservoir: shaly-sands or carbonates with highly radioactive black organic material or presence of radioactive material in factures. We have tested our new equation for carbonate reservoirs in Venezuela and Mexico; shaly-sands reservoirs in Colombia, Venezuela including deepwaters in the Gulf of Mexico. In all cases, the calculated Vshale volumes have been validated with the X-ray diffraction data or the elemental capture spectroscopy (ECS) logs that quantify the actual clay volume (Vsh) and achieve correlation coefficients, r2, greater than 0.92.
Short-Term and Long-Term Optimizations for Reservoir Management with Intelligent Wells
Authors: Pinto Marcio Augusto , Gildin Eduardo , Schiozer Denis José 
Published: November 2015

Abstract
Short-term optimization of an oil field has been used to increase economic value of oil recovery as compared to reactive control (shutting the well when water cut limit is reached, for instance), especially in the case of short-term production strategies. One way to improve the management of a field involves adjusting the production flow rates over a short time, maximizing the overall NPV during the life cycle of the field. Using intelligent wells (IW), the challenges include not only the optimization of well flow rates, but also the simultaneous adjustment of flow in each valve, controlling each aperture in a given production time. These optimal control strategies are often difficult to be realized in practice due to the large number of control variables involved in the optimization process, especially with larger number of wells and valves. To this end, this work proposes an efficient optimization framework employing a fast genetic algorithm (FGA) in order to adjust simultaneously the flow rates of wells and the valves aperture. We have used a commercial reservoir simulator whereby the flow rates of wells were optimized with an option available that calculates well rates when there is production constraint on the wells (platform capacity or other operational constraint) using production parameters in real time; and at the same time the flow in each valve was controlled through a keyword associated with the control of the aperture of valves by monitoring the pressure drop around of them. The FGA optimization algorithm employed is a global optimization method, which is robust and efficient for sweeping the solution space with many variables, and it is able to work with continuous and discrete variables simultaneously. We demonstrate the power of the FGA strategy by applying the methodology to a heterogeneous reservoir model based on Brazil's Namorado field, with four horizontal producers and four horizontal injector wells. Two producers were tested as intelligent, using two valves of continuous variation type. The rate of wells was determined using water cut values while there were constraints on the production of the platform. The valves were adjusted each 60 days, during the first four years of production, closing in the optimal time at the end of production. The results showed an improvement in reservoir management, increasing 3.7% of NPV, with additional gains around US$ 20 million (already discounted the costs of intelligent completion), increasing oil production and reducing water production. The combination of the tools available in a commercial simulator jointly with global optimization algorithm showed advantages of the operation of the wells and valves simultaneously.
A Mechanistic Understanding of Asphaltene Precipitation from Varying Saturate Concentration Perspective
Authors: Prakoso A. A. , Punase A. D. , Hascakir B. 
Published: November 2015

Abstract
Asphaltene precipitation can severely hamper the petroleum extraction by plugging the pores or precipitation in production lines. Although the effect of temperature and pressure on asphaltene deposition is well known, how the variations in oil composition affect the asphaltene precipitation mechanism requires more clarity. This work investigates the effect of compositional changes on asphaltene stability. The impact of oil composition is explained by preparing pseudo-components by blending the crude oil with their own saturate fractions.
A systematic characterization of 11 different bitumen and crude oil samples is carried out on the basis of their density, viscosity, asphaltene content, and asphaltene composition. n-pentane is used to determine the asphaltene content of each sample by following a standard method. The asphaltene composition is then determined with Fourier Transform InfraRed (FTIR) spectroscopy. The asphaltene stability is tested by performing the onset asphaltene precipitation (OAP) tests.
The results from the characterization study indicated that there is no direct relationship between the asphaltene content and the density or the viscosity of the bulk samples. However, the FTIR profiles suggest that the polarity of the asphaltene molecules greatly influence the size of the precipitated clusters. The outcomes from the OAP tests were used to decipher the thermodynamic equilibrium state on the mechanism of asphaltene destabilization as per the change in the polar (resins and asphaltenes) to nonpolar (saturates and aromatics), saturates to aromatics, and resins to asphaltenes fraction of the bulk sample. It was observed that the increase in saturates concentration destabilized the asphaltene molecules and resulted in more precipitation. The presence of polar functional groups, as observed from the FTIR of the saturate fraction are believed to cause higher asphaltene precipitation.
During oil production, the temperature and pressure changes can lead to asphaltene deposition and alteration in the crude oil chemical composition. A holistic understanding of the thermodynamic equilibrium corresponding to these changes can be achieved by analyzing asphaltene destabilization or restabilization processes, specifically by changing the saturate concentrations. These results are extremely useful to comprehend the asphaltene stabilization mechanism and can improve the accuracy of existing asphaltene models.
Effects of Single Rainfall Events on Leaching of Glyphosate and Bentazone on Two Different Soil Types, using the DAISY Model
Authors: Rasmussen Signe B. , Abrahamsen Per , Nielsen Marie H. , Holm Peter E. , Hansen Søren 
Published: October 2015

Core Ideas
Modeling pesticide leaching during a single rainfall event with temporal variability.
Short intense events (1 h) resulted in high glyphosate leaching to subsurface drains.
Event volume controlled pesticide leaching at coarse sandy soil.
The purpose of the present modeling study was to contribute to an improved understanding of the mechanisms involved in pesticide leaching during a single rainfall event with temporal variability. Rainfall intensity of the first event after pesticide application has great effect on the amount of pesticide transported to groundwater and subsurface drains, especially in soils containing preferential flow pathways. One way to improve the understanding of single event properties on pesticide leaching is to use a transport model. The soil–plant–atmosphere model Daisy was used to simulate pesticide leaching during and after single rainfall events of different durations and intensities. Designed temporally variable single rainfall events based on the Chicago Design Rain were inserted in the original weather file. A combination of different intensities (13, 20, 24, 28, 34, and 39 mm h−1) at different event durations (1, 3, 5, and 9 h) where the intensity peak was placed in the middle of the event ware applied, resulting in 24 different design events. The model setup included two different soil types: a coarse sandy soil and a sandy loam containing macropores and subsurface drains. The fates of the herbicides bentazone [3‐isopropyl‐1H‐2,1,3‐benzothiadiazin‐4(3H)‐one 2,2‐dioxide] and glyphosate [N‐(phosphonomethyl)glycine] were simulated. The leaching dynamics of both pesticides showed high variability at the hourly level, illustrating the importance of high model resolution when estimating pesticide leaching. For the coarse sandy soil different intensities did not appear to have an effect, as pesticide leaching was controlled by event volume. In contrast, results for the sandy loam showed an effect of intensity, especially for glyphosate, at initially wet soil conditions. Short intense events (1 h) resulted in high leaching to drains (1.7% of matrix infiltration) compared to events of longer duration (up to 0.4% of matrix infiltration). This indicates that it might be more prudent to view leaching as a risk that occurs under certain conditions, rather than something that can be averaged.
Visualizing Large Data Sets: Spatial and Temporal Soil Moisture Regime Dynamics
Authors: Miller Jeffrey Frederick , Loheide Steven P. 
Published: October 2015

Core Ideas• A novel technique is developed for displaying large soil moisture data sets• Spatial and temporal soil moisture regime characteristics are captured• System dynamics are conveyed without plotting subjective profiles or historiesDespite constituting a small portion of global water, soil moisture controls regional to continental precipitation patterns, soil biogeochemistry, C and nutrient cycling, watershed rainfall–runoff response, and vegetation patterning. While advanced, spatially and temporally distributed soil moisture measurement and prediction techniques are necessary for improving understanding of vadose zone processes, they generate a wealth of data that are difficult to visualize in a manner that conveys salient features of system dynamics. Specifically, visualizations using soil moisture profiles or time series require subjective selection of times or locations, respectively, and inevitably fail to capture the majority of the data. We developed a method for visualizing the complete soil moisture regime using time series data measured or simulated along a one‐dimensional spatial domain, which maintains the spatial relationship of measurement locations and conveys a sense of the variability of soil moisture at each location ordinate without the subjectivity of selecting representative soil moisture profiles for plotting. This technique is capable of conveying relevant features of soil moisture dynamics, such as the influence of soil texture, precipitation, plant water use, and groundwater interactions, by using (i) simulated soil moisture data from an ecohydrological model and (ii) field data collected using an advanced, spatially distributed measurement technique. Visualization techniques such as this one will be useful for developing insight into vadose zone processes and validating sophisticated vadose zone models with field data.
Oxidizer Demand in the Unsaturated Zone of a Surface‐Spreading Soil Aquifer Treatment System
Authors: Elkayam Roy , Sopliniak Alex , Gasser Guy , Pankratov Irene , Lev Ovadia 
Published: October 2015

Core Ideas
We investigated the Shafdan SAT system, known for its good performance.
We showed that oxidation of organic and nitrogen compounds occurs in the vadose zone.
We calculated the oxidizer balance over the vadose zone and the overall system.
The balance reveals 42.5 ± 12. mg/L of oxygen consumption in the vadose zone.
Soil aquifer treatment (SAT) is increasingly considered to be a favorable polishing method before the use of secondary or tertiary wastewater effluents for unrestricted irrigation or disposal to the sea. Most of the oxidation processes of organic compounds as well as of nitrogen compounds take place in the unsaturated zone of the SAT. A material balance over the unsaturated zone of a high‐frequency SAT system reveals that 90% of the removal of organic matter and complete ammonium oxidative removal already occur within the unsaturated zone. This is observed, despite the short (less than 3 wk) water retention time in this zone, compared with the subsequent 6‐ to 36‐mo retention time within the aquifer. An oxidizer balance over the unsaturated zone reveals that 42.5 ± 12 mg/L of oxygen is consumed in the unsaturated zone. This consumption level is five times higher than the oxygen saturation level under the conditions prevailing in the effluent. The implications of this excessively high oxygen demand in the vadose zone on manganese mobilization in the aquifer are addressed.
Long-term Effect of Optimized Sedation and Pain Management after Sudden Cardiac Arrest
Authors: Abanador-Kamper Nadine , Wolfertz Judith , Thürmann Petra , Kamper Lars , Seyfarth Melchior 
Published: October 2015

Background and Aims:
Appropriate use of sedatives and analgesics is essential to keep critically ill patients
comfortable and to prevent prolonged mechanical ventilation time and length of stay in ICU. Aim of this study was to
analyse the long-term effect of an algorithm-based individual analgesic-sedative protocol on mechanical ventilation time
and ICU length of stay in critically ill patients after sudden cardiac arrest due to ST-elevated myocardial infarction.

Subject and Methods:
We examined a total of 109 patients before and after implementation of an algorithm-based sedation
management. Our sedation protocol included individual defined sedation goals achieved by standardized sedation
strategies. Mechanical ventilation time and ICU length of stay were analysed for three groups of patients: before and after
the intervention and in the long-term follow-up.

Results:
We observed shorter median mechanical ventilation time and ICU length of stay in the interventional and longterm
follow-up group compared to the standard-care group without statistical significance.

Conclusion:
Our results demonstrate a long-term reduction of mechanical ventilation time and ICU length of stay
achieved by implementation of an individual sedation management. This suggests sedation guidelines as effective tools to
reduce the mechanical ventilation time and ICU length of stay in patients after sudden cardiac arrest in ST-elevated myocardial
infarction. Investigations with a larger patient number and higher statistical power are required to confirm these
findings.
Dental and skeletal changes in mild to moderate Class II malocclusions treated by either a Twin-block or Xbow appliance followed by full fixed orthodontic treatment
Authors: Ehsani Sayeh , Nebbe Brian , Normando David , Lagravere Manuel O , Flores-Mir Carlos 
Published: October 2015

ABSTRACT

Objective:
To compare the short-term skeletal and dental effects of two-phase orthodontic treatment including either a Twin-block or an XBow appliance.

Materials and Methods:
This was a retrospective clinical trial of 50 consecutive Class II cases treated in a private practice with either a Twin-block (25) or XBow (25) appliance followed by full fixed orthodontic treatment. To factor out growth, an untreated Class II control group (25) was considered.

Results:
A MANOVA of treatment/observation changes followed by univariate pairwise comparisons showed that the maxilla moved forward less in the treatment groups than in the control group. As for mandibular changes, the corpus length increase was larger in the Twin-block group by 3.9 mm. Dentally, mesial movement of mandibular molars was greater in both treatment groups. Although no distalization of maxillary molars was found in either treatment group, restriction of mesial movement of these teeth was seen in both treatment groups. Both treatment groups demonstrated increased mandibular incisor proclination with larger increases for the XBow group by 3.3°. The Wits value was decreased by 1.6 mm more in the Twin-block group. No sex-related differences were observed.

Conclusions:
Class II correction using an XBow or Twin-block followed by fixed appliances occurs through a relatively similar combination of dental and skeletal effects. An increase in mandibular incisor inclination for the XBow group and an increased corpus length for the Twin-block group were notable exceptions. No overall treatment length differences were seen.
Outcomes of dogs undergoing radiotherapy for treatment of oral malignant melanoma: 111 cases (2006–2012)
Authors: Kawabe Mifumi , Mori Takashi , Ito Yusuke , Murakami Mami , Sakai Hiroki , Yanai Tokuma , Maruo Kohji 
Published: October 2015

Abstract
Objective—To evaluate the characteristics and outcomes of dogs with stage I, II, III, or IV oral malignant melanoma treated by various types of radiotherapy.
Design—Retrospective case series.
Animals—111 dogs.
Procedures—Medical records of dogs with oral malignant melanoma treated by radiotherapy (with or without adjunctive treatments) at a veterinary medical center between July 2006 and December 2012 were reviewed. Information regarding signalment, tumor location, disease stage, treatment protocols, adverse effects, and survival time were obtained from medical records and by telephone follow-up. Associations between variables of interest and outcome were analyzed.
Results—Dogs received orthovoltage x-ray (n = 68), megavoltage x-ray (39), or electron beam (4) radiotherapy. Adjunctive treatments included debulking surgery (n = 18), chemotherapy (39), or both (27). Median survival times for dogs with stage I, II, III, and IV melanoma were 758 days (n = 19), 278 days (24), 163 days (37), and 80 days (31), respectively, and differed significantly between dogs with stage I disease and those with all other disease stages. Among dogs with stage III melanoma, risk of death was significantly higher in those that received orthovoltage x-ray treatment than in those that received megavoltage x-ray treatment. Severe (primary or secondary) adverse effects were identified in 9 dogs.
Conclusions and Clinical Relevance—Median survival time was significantly longer for dogs with stage I oral malignant melanoma than for dogs with more advanced disease at the time of staging. The staging system used may be a useful tool for prognosis prediction in dogs undergoing similar treatment protocols for oral malignant melanomas.
Unilateral C-1 posterior arch screws and C-2 laminar screws combined with a 1-side C1–2 pedicle screw system as salvage fixation for atlantoaxial instability
Authors: Guo-Xin Jin , Huan Wang 
Published: October 2015

OBJECT
Atlantoaxial instability often requires surgery, and the current methods for fixation pose some risk to vascular and neurological tissues. Thus, new effective and safer methods are needed for salvage operations. This study sought to assess unilateral C-1 posterior arch screws (PASs) and C-2 laminar screws (LSs) combined with 1-side C1–2 pedicle screws (PSs) for posterior C1–2 fixation using biomechanical testing with bilateral C1–2 PSs in a cadaveric model.

METHODS
Six fresh ligamentous human cervical spines were evaluated for their biomechanics. The cadaveric specimens were tested in their intact condition, stabilization after injury, and after injury at 1.5 Nm of pure moment in 6 directions. The 3 groups tested were bilateral C1–2 PSs (Group A); left side C1–2 PSs with an ipsilateral C-1 PAS + C-2 laminar screw (Group B); and left side C1–2 PSs with a contralateral C-1 PAS + C-2 LS (Group C). During the testing, angular motion was measured using a motion capture platform. Data were recorded, and statistical analyses were performed.

RESULTS
Biomechanical testing showed that there was no significant difference among the stabilities of these fixation systems in flexion-extension and rotation control. In left lateral bending, the bilateral C1–2 PS group decreased flexibility by 71.9% compared with the intact condition, the unilateral C1–2 PS and ipsilateral PAS+LS group decreased flexibility by 77.6%, and the unilateral C1–2 PS and contralateral PAS+LS group by 70.0%. Each method significantly decreased C1–2 movements in right lateral bending compared with the intact condition, and the bilateral C1–2 PS system was more stable than the C1–2 PS and contralateral PAS+LS system (p = 0.036).

CONCLUSIONS
A unilateral C-1 PAS + C-2 LS combined with 1-side C-1 PSs provided the same acute stability as the PS, and no statistically significant difference in acute stability was found between the 2 screw techniques. These methods may constitute an alternative method for posterior atlantoaxial fixation.
Enlargement of the middle meningeal artery on MR angiography in chronic subdural hematoma
Authors: Takizawa Ken , Sorimachi Takatoshi , Ishizaka Hideo , Osada Takahiro , Srivatanakul Kittipong , Momose Hiroaki , Matsumae Mitsunori 
Published: October 2015

OBJECT
The middle meningeal artery (MMA) is suspected to play an important role in the development of chronic subdural hematoma (CSDH). The aim of this study was to clarify whether the MMA was enlarged in patients with CSDHs.

METHODS
The authors retrospectively assessed 55 patients in whom CSDH was diagnosed between 2010 and 2014 and who underwent MR angiography (MRA) after the onset of CSDH. The authors compared MMA diameters between hemispheres with and without CSDHs on MR angiograms. A case-control study was also performed with 55 sex- and age-matched patients with incidental unruptured aneurysms as controls.

RESULTS
In 55 patients with CSDHs, the diameters of the 79 MMAs on the CSDH side were significantly larger than the diameters of the 31 MMAs on the non-CSDH side (p < 0.05). In 24 patients with bilateral CSDHs, no significant difference was found between the MMA diameters on the larger hematoma side and those on the smaller hematoma side. In 13 patients who underwent MRA before the onset of the CSDH, the MMAs on MR angiograms acquired after onset of the CSDH were significantly larger than those on MR angiograms acquired before the CSDH onset (p < 0.05). The diameters of the MMAs in 55 patients with CSDHs were significantly larger than those of the MMAs in the 55 control patients (p < 0.05).

CONCLUSIONS
The MMA is enlarged with development of a CSDH. Information about the MMA observed on MRA in patients with CSDHs may be useful in developing a strategy for future treatment of CSDHs.