bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Kinesitherapy on Functional Independence in Patients with Supratentorial Unilateral Stroke in Chronic Period
Authors: Vasileva Danche , Lubenova Daniela , Zaharieva Darina , Grigorova-Petrova Kristin , Nikolova Milena , Bizeva Tzvetalina 
Published: January 2018

Aim: The aim of the study is to evaluate the effect of the specialized kinesitherapeutic (KT) methodology (SKTM) on functional independence in patients with supratentorial unilateral stroke in the chronic period (SUSChP). Material and Methods: The study was conducted with 67 patients with SUSChP (56 patients included in the experimental group - 32 men and 24 women, with duration of the disease 7.8 ± 2.0 months, and 11 patients in the control group - 9 men and 2 women, with duration of the disease 7.3 ± 1.5 months). To evaluate the changes in functional independence, test for Functional Independence Measure (FIM) was used. Patients in the experimental group were treated with a specialized 10-day KT, which later continued to be performed as an adapted exercise program at home for a period of one month. Control patients perform a regular 10-day KT. This was done using SKTM principles of modern neurorehabilitation and motor learning as opposed to usual kinesitherapy. Results: After applying SKTM, the highest trend towards the improvement of functional independence was established after the 1st month with a level of significance during treatment p<0.001. Conclusion: In conclusion, the enclosed SKTM in the experimental group continued later as an adapted exercise program at home. It significantly improves the functional independence in patients with supratentorial unilateral stroke in the chronic period (SUSChP) compared with the usual kinesitherapeutic methodology applied in the control group.
OPTIMASI PRODUKSI TUTUP BOTOL 500 ml PADA PROSES INJECTION MOULDING MENGGUNAKAN METODE RESPONSE SURFACE
Authors: Putra Kurniawan Purnama , R. W. R. Koekoeh 
Published: January 2018

Injection molding is one of the most common operations and versatile for mass production of complex plastic components. Injection molding is a process of plastic forming into a desired shape by means of pressing molten plastic into a space (cavity). Injection molding has a multi-step process, starting from inserting plastic pellets into the hopper, then plastic pellets into barrels / heating which makes the plastic material is melted. Melting plastic material is driven by the rotation of the screw, so that the flow to the nozzle, and then toward the sprue, runner, gate and into the cavity. Then the material present in the cavity will be retained within the mold under a certain pressure (holding pressure) to keep no shringkage when the product cooling process (cooling).The purpose of this study was to obtain the optimization of the cycle time and the percentage of production reject the bottle cap 500 ml in PT Berlina Tbk. The method used for this research is the method of response surface analysis, method surface respone is statistical and mathematical methods used to examine the relationship between one or more variables with the qualitative form of the response variables that aims to optimize and develop the response in an experiment. The data is optimized using Minitab software 16 produces an output response parameter setting optimization to inject pressure, nozzle temperature and cooling time. From the data analysis using the software Minitab 16 is obtained from the optimum situation results generated under conditions injection amounting to 1420 bar pressure; nozzle temperature at 264.7912 ° C; and the cooling time of 14.08 seconds. In this state of production can be increased by 10.836%. From the state of the optimum cycle time generated is 27.9161 seconds, net produced according to the standard that is 33.5820 grams and reject percentage the resulting is 11.11%. With a cycle time 27.9161 seconds with a net according to the standard and the percentage of rejects decreased 3.89%, the resulting product amounts to ± 15,517 /shift or up approximately 10.836%. The amount is based on the number of products produced in the cycle time previous of 30 seconds to produce ± 14,000 /shift.
Keywords: Injection moulding, box-benhken design, Response surface methodology
Effects of liming on soil properties, leaf tissue cation composition and grape yield in a moderately acid vineyard soil. Influence on must and wine quality
Authors: QUIROGA Miguel Javier , OLEGO Miguel Ángel , SÁNCHEZ-GARCÍA Mario , MEDINA Jesús Esteban , VISCONTI Fernando , COQUE Juan José Rubio , GARZÓN JIMENO José Enrique 
Published: January 2018

Aims: Soil acidity decreases soil fertility and grapevine growth. Aluminum toxicity has been recognized as one of the most common causes of reduced grape yields in acid vineyard soils. The main aim of this study was to evaluate the effect of two liming materials, i.e. dolomitic lime and sugar foam, on a vineyard cultivated in an acid soil.Methods and results: The effects were studied in two soil layers (0-30 and 30-60 cm), as well as on leaf nutrient contents, grape yield, and must and wine quality properties, in a vineyard dedicated to Vitis vinifera L. cv. Mencía cultivation. The data management and analysis were carried out using ANOVA.Conclusion: Sugar foam was more efficient than dolomitic limestone as liming material since it induced the highest decrease in soil acidity properties at the same calcium carbonate equivalent dose. Effects of liming on leaf nutrient contents, grape yield, and must and wine quality properties were barely observed.Significance and impact of the study: Until recently, little was known about the effects of liming on both vine nutritional status and must/wine quality properties. Thus, this research fills an important knowledge gap.
Quantifying Expected Uncertainty Reduction and Value of Information Using Ensemble-Variance Analysis
Authors: He Jincong , Sarma Pallav , Bhark Eric , Tanaka Shusei , Chen Bailian , Wen Xian-Huan , Kamath Jairam 
Published: January 2018

Summary
Data-acquisition programs, such as surveillance and pilots, play an important role in minimizing subsurface risks and improving decision quality for reservoir management. For design optimization and investment justification of these programs, it is crucial to be able to quantify the expected uncertainty reduction and the value of information (VOI) attainable from a given design. This problem is challenging because the data from the acquisition program are uncertain at the time of the analysis. In this paper, a method called ensemble-variance analysis (EVA) is proposed. Derived from a multivariate Gaussian assumption between the observation data and the objective function, the EVA method quantifies the expected uncertainty reduction from covariance information that is estimated from an ensemble of simulations. The result of EVA can then be used with a decision tree to quantify the VOI of a given data-acquisition program.
The proposed method has several novel features compared with existing methods. First, the EVA method directly considers the data/objective-function relationship. Therefore, it can handle nonlinear forward models and an arbitrary number of parameters. Second, for cases when the multivariate Gaussian assumption between the data and objective function does not hold, the EVA method still provides a lower bound on expected uncertainty reduction, which can be useful in providing a conservative estimate of the surveillance/pilot performance. Finally, EVA also provides an estimate of the shift in the mean of the objective-function distribution, which is crucial for VOI calculation. In this paper, the EVA work flow for expected-uncertainty-reduction quantification is described. The result from EVA is benchmarked with recently proposed rigorous sampling methods, and the capacity of the method for VOI quantification is demonstrated for a pilot-analysis problem using a field-scale reservoir model.
Transient-Inflow-Performance Modeling From Analytic Line-Source Solutions for Arbitrary-Trajectory Wells
Authors: Hazlett R. D. , Babu D. K. 
Published: January 2018

Summary
We present two easily computable, equally valid, semianalytic, single-phase, constant-rate solutions to the diffusivity equation for an arbitrarily oriented uniform-flux line source in a 3D, anisotropic, bounded system in Cartesian coordinates. With the addition of superposition, these become inflow solutions for wells of arbitrary trajectory. In addition, we produce analytic time derivatives for pressure-transient analyses (PTAs) of complex wells. If we extract solution components for 2D systems from the general solution, we can construct discrete complex-fracture-inflow and PTA capability for vertical, fully penetrating fractures, suitable for use as the basis solution in modeling complex phenomena, such as pressure-constrained production or development of fracture interference. For a 3D slanted well, the full characterization of dimensionless pressure over 10 decades of dimensionless time behavior can be produced in 1.5 seconds. With a fast-computing analytic solution for pressure anywhere in the system, we can also produce dense pressure maps at scalable resolution where any point could represent an observation well for convolution and enhanced interpretation. Likewise, the pressure derivative and the slope of the logarithmic temporal derivative of pressure can be mapped throughout to indicate local flow regime in a complex system. In particular, we compare and contrast the PTA signatures from symmetrical and asymmetrical horizontal, slanted, and diagonal line sources and examine when the behavior of a thin 3D reservoir collapses to the equivalent of a 2D fully penetrating fracture. Once the reservoir-thickness/length ratio reaches 1:100, all wells with the same projection onto the x–y plane are indistinguishable except for very early time, probably masked by wellbore/fracture-storage effects.
Hydraulic Fracture Height Growth Under the Combined Influence of Stress Barriers and Natural Fractures
Authors: Huang Jixiang , Morris Joseph P. , Fu Pengcheng , Settgast Randolph R. , Sherman Christopher S. , Ryerson Fredrick J. 
Published: January 2018

Abstract
Fracture height control is an important concern in stimulation design. Existing knowledge of interaction mechanisms between hydraulic fractures, natural fractures, and source rock fabric has been largely obtained from 2D or pseudo-3D models. The recent advances in full-3D hydraulic fracture modeling capabilities reveal previously-unknown 3D interaction mechanisms on fracture height growth. A fully coupled finite element/finite volume code is used for modeling 3D hydraulically driven fractures with arbitrary geometries under the influence of natural fractures and stress barriers. Both hydraulic fractures and natural fractures are represented in a unified framework by split interfaces between solid elements that represent the rock continuum. Fracture flow elements and frictional contacts are deployed along the split interface, generating fluid pressure and contact stress applied to the rock faces on both sides as traction boundary conditions. Fracture dilation/propagation/sliding and the resultant stress alteration are natural outcomes of the model.
The current study focuses on the influence of strong variations in closure stress interacting with natural fractures upon hydraulic fracture propagation. We observe that the slipping of a natural fracture, triggered by elevated fluid pressure from an intersecting hydraulic fracture, can induce both increases and decreases of normal stress in the minimum horizontal stress direction, toward the center and tip of the natural fracture respectively. Consequently, we expect that natural fractures can both encourage and inhibit the progress of hydraulic fractures propagating through stress barriers, depending upon the relative locations between the intersecting fractures. Once the hydraulic fracture propagates above the stress barrier through the weaken segment near a favorably located natural fracture, a configuration consisting of two opposing fractures cutting the stress barrier from above and below forms. The fluid pressure required to break the stress barrier under such opposing-fracture configuration is substantially lower than that required by a fracture penetrating the same barrier from one side. Sensitivity studies of geologic conditions and operational parameters have also been performed to explore the feasibility of controlled fracture height. We demonstrate that the interactions between hydraulic fractures, natural fractures, and geologic factors such as stress barriers in 3D are much more complex than in 2D. Although it is impossible for a specific study to exhaust all the possible configurations, we demonstrate the ability of a 3D, fully coupled numerical model to naturally capture these processes.
Benchmark Modeling of Hydraulic Fracture Interaction with Pre-Existing Fractures: Impact on Fracture Geometry, Proppant Distribution and Microseismic Response
Authors: Maxwell S. C. , Hazzard J. , Pettitt W. 
Published: January 2018

Abstract
A modeling exercise was performed investigating hydraulic fracture interaction with pre-existing fractures, based on a benchmark modeling exercise lead by ARMA (American Rock Mechanics Association). The modeled scenarios are based on interaction with two existing faults under different geomechanical conditions. Simulations were performed with a coupled hydraulic-geomechanical-seismological, discrete-element model. The results show that the hydraulic fracture aperture is restricted at the intersection with the faults, to a degree depending on the slip induced on the fault. The aperture restriction was found to also limit the extent of the proppant distribution. In scenarios with relatively more slip, the fault activation was found to occur above and below the injection layer and resulted in some hydraulic fracture height growth relative to the depth contained fracture occurring without fault activation. As expected, the fault slip and intensity of associated microseismicity is related to the geomechanical prepotency for slip. Fractures oriented at 30° to the hydraulic fracture and maximum principal stress direction, resulted in the largest microseismic magnitude and significant hydraulic fracture restriction at the fault intersection. With increasing angle, the magnitude decreased and the hydraulic fracture had a larger half-length. Increasing the differential stress resulted in increased magnitudes and decreased fracture half-length, as did the case of a weaker fault. The study demonstrates through a numerical-physics simulation how a hydraulic fracture system behalves as it interacts with a pre-existing fracture under various geomechanical conditions.
Mining the Bakken II – Pushing the Envelope with Extreme Limited Entry Perforating
Authors: Weddle Paul , Griffin Larry , Pearson C. Mark 
Published: January 2018

Abstract
This paper presents the continuing evolution of our Bakken advanced completion design with the added enhancement of Extreme Limited Entry (XLE) perforating. With this cost-effective XLE strategy, we are consistently stimulating more than eleven perforation clusters per stage. Confirmation of this high number of active clusters, or fracture initiation points, has been directly measured with radioactive tracers and fiber optic diagnostics, and more importantly, is validated through improved production relative to offset completions. The goal of this strategy is to consistently and confidently drive a high number of clusters per stage, ultimately increasing capital efficiency by right sizing the cluster and stage count per well.
Practically, the number of stages for a 9,500-ft. lateral is limited to 40 or 50 stages in the Bakken due to operational and cost limits. We believe the published trends on stage count are fundamentally linked to the number of active clusters per stage or fracture initiation points, and by driving significantly more active clusters per stage with XLE perforating in combination with previously presented High Density Perforating (HDP), we now have proven the ability to reduce stage count without sacrificing performance.
Liberty now incorporates XLE as a key design technique to successfully stimulate 15 clusters per stage. Production performance is encouraging and post frac fiber optic diagnostics support prior radioactive proppant tracer data in showing that over 11 of the 15 clusters shot can be stimulated with slickwater at 80 bpm. XLE operational considerations for frac plug ratings, oriented perforating, even-hole perforating charges, variable pipe friction and a review of existing papers on limited entry are included as well.
Limited entry perforating has been around for over 50 years; however, its effectiveness has been limited in the horizontal revolution due to insufficient perforation friction relative to the variability in stress and near-wellbore tortuosity found within a stage. This paper presents the improved results for specifically designing perforations and stimulation injection rates to achieve diversion to almost all 15 perforation clusters per stage. For this paper, we define XLE as completion designs with perforation friction exceeding 2,000 psi. Since the beginning of 2015 we have reduced our standard stage count from 50 down to 27, for a 9,500-ft lateral, while continuing to significantly outperform offset operators. When it comes to value creation, the cost per barrel of oil produced is a critical metric to assess development opportunities and achieving the same or increased oil production with less capital has led to significant gains in capital efficiency.
Proppant Transport in Complex Fracture Networks
Authors: Shrivastava Kaustubh , Sharma Mukul M. 
Published: January 2018

Abstract
During hydraulic fracturing, natural fractures and bedding planes can intersect with growing hydraulic fractures and form complex fracture networks. This can result in the flow of fluid and proppant in convoluted fracture pathways with highly variable fracture width and height. Existing models of hydraulic fracturing assume a planar fracture geometry and are unable to simulate proppant placement in such complex networks. In this work, we investigate proppant transport in growing fracture networks using a fully three-dimensional, geomechanical fracture flow, network model with the ability to simulate proppant transport.
A three-dimensional hydraulic fracturing simulator developed using the displacement discontinuity method is coupled with a network model for proppant transport. The simulator captures the effect of proppant concentration, fracture width, and fluid rheology on proppant transport. The equations for the fracture network geomechanics, the fluid flow, and the proppant transport are solved in a coupled manner. This provides an accurate estimation of both the fluid pressure and the proppant distribution as the fracture network grows. The geometry of each fracture segment affects the flow distribution in the network. Simulations are then conducted to study the redistribution of proppant as it settles in the fracture network during shut-in to get the final proppant distribution in the network.
It is observed that changes in the in-situ stress due to heterogeneity and the stress-shadow induced near the intersection of a hydraulic fracture and a natural fracture may reduce the fracture width and suppress the ability of the proppant to move into the natural fracture. In low permeability formations, due to low leak-off rates, the proppant almost always forms a proppant bank at the bottom of the fracture during shut-in. For planar fractures, proppant settling may disconnect the conductive proppant bank from the wellbore, isolating the productive propped fracture from the wellbore. This problem is exaggerated in the case of fracture networks, where every intersection point between fractures can potentially act as a bottleneck for the flow of produced hydrocarbons. The increase in the surface area due to hydraulically connected natural fractures increases fluid leak-off, reduces the average width of the fracture network, increases proppant concentration, and increases the likelihood of proppant bridging.
This work allows us to improve our understanding of proppant placement in three-dimensional, mechanically interacting, complex fracture networks. By coupling geomechanics with proppant transport in fracture networks, it is now possible to study the impact of the stress shadow on proppant placement in natural fractures. The results will assist in improving hydraulic fracture design for naturally fractured reservoirs.
Fracturing in a Tectonically Stressed Area under Anomalously High Gradients
Authors: Abdrazakov Dmitriy , Bolyspayev Nurlan , Voigtlaender Gernot , Nauruzov Talgat , Bigeldiyev Asfandiyar 
Published: January 2018

Abstract
Increasing depth of exploration wells usually results in elevated fracturing gradients and decrease of permeability of the formations. Adding tectonic stresses and well deviation to these conditions may result in a distorted stress field with anomalous fracturing and breakdown gradients, thus causing multiple complexities. In case studies, 11 fracturing treatments performed at high fracturing gradients in the same oil field were analyzed, and the following complicating factors were distinguished: high treating pressures, anomalous breakdown gradients, inability to place planned amount of proppant due to near-wellbore complexity, accelerated leakoff in opened fissures, and accumulation of the stress at the formation with each successive pumping cycle. These factors can be attributed to the combination of the reservoir properties, well placement, and well completion techniques: high tectonic stress is a basic cause of increased fracturing pressures, well deviation is a substantial contributor to the increase in the breakdown pressures, reservoir poroelastic properties are the reason for the accumulation of the back-stress, and perforation strategy is the key factor in the near-wellbore complexity. An explanation of each factor is given in the current paper, with the case study examples. Prevention and mitigation measures are proposed, based on the experience from the considered cases and literature review.