Методологія визначення оптимальних технологічних параметрів транспортної інфраструктури при обслуговуванні зернових вантажопотоків

Комплексно проаналізовано на прикладі функціонування багатоканальної динамічної системи з кінцевим числом степенів свободи можливість покращення економічних показників транспортної системи при узгодженні інфраструктурних параметрів для обслуговування підприємств елеваторно-складського господарства. Охарактеризована залежність числового значення логістичних витрат в системі з двома вузлами обслуговування.Комплексно проанализирована на примере функционирования многоканальной динамической системы с конечным числом степеней свободы возможность улучшения экономических показателей транспортной системы при согласовании инфраструктурных параметров для обслуживания предприятий элеваторно-складского хазяйства. Охарактеризована зависимость числового значения логистических расходов в системе с двумя узлами обслуживания.In possibility of improving the economic indicators of a transport system is fully analyzed in the concordance of infrastructural parameters for maintenance of elevator-store enterprises with using, as an example, functioning of a multichannel dynamic system with the finite number of degrees of freedom. The numerical value of logistic charges for the system with two knots is described

Kinetics of Low-Salinity-Flooding Effect

Summary Low-salinity waterflooding (LSF) is one of the least-understood enhanced-oil-recovery (EOR)/improved-oil-recovery (IOR) methods, and proper understanding of the mechanism(s) leading to oil recovery in this process is needed. However, the intrinsic complexity of the process makes fundamental understanding of the underlying mechanism(s) and the interpretation of laboratory experiments difficult. Therefore, we use a model system for sandstone rock of reduced complexity that consists of clay minerals (Na-montmorillonite) deposited on a glass substrate and covered with crude-oil droplets and in which different effects can be separated to increase our fundamental understanding. We focus particularly on the kinetics of oil detachment when exposed to low-salinity (LS) brine. The system is equilibrated first under high-salinity (HS) brine and then exposed to brines of varying (lower) salinity while the shape of the oil droplets is continuously monitored at high resolution, allowing for a detailed analysis of the contact angle and the contact area as a function of time. It is observed that the contact angle and contact area of oil with the substrate reach a stable equilibrium at HS brine and show a clear response to the LS brine toward less-oil-wetting conditions and ultimately detachment from the clay substrate. This behavior is characterized by the motion of the three-phase (oil/water/solid) contact line that is initially pinned by clay particles at HS conditions, and pinning decreases upon exposure to LS brine. This leads to a decrease in contact area and contact angle that indicates wettability alteration toward a more-water-wet state. When the contact angle reaches a critical value at approximately 40 to 50°, oil starts to detach from the clay. During detachment, most of the oil is released, but in some cases a small amount of oil residue is left behind on the clay substrate. Our results for different salinity levels indicate that the kinetics of this wettability change correlates with a simple buoyancy- over adhesion-force balance and has a time constant of hours to days (i.e., it takes longer than commonly assumed). The unexpectedly long time constant, longer than expected by diffusion alone, is compatible with an electrokinetic ion-transport model (Nernst-Planck equation) in the thin water film between oil and clay. Alternatively, one could explain the observations only by more-specific [non- Derjaguin–Landau–Verwey–Overbeek (DLVO) type] interactions between oil and clay such as cation-bridging, direct chemical bonds, or acid/base effects that tend to pin the contact line. The findings provide new insights into the (sub) pore-scale mechanism of LSF, and one can use them as the basis for upscaling to, for example, pore-network scale and higher scales (e.g., core scale) to assess the impact of the slow kinetics on the time scale of an LSF response on macroscopic scales.</jats:p

A growing sense of well-being: a literature review on the complex framework well-being.

This review examines the origin and structure of the complex well-being (WB) concept as it is currently applied in behavioral and social sciences. Current research on WB is often divided into two perspectives: subjective well-being (SWB) and psychological well-being (PWB), shaped by the philosophical concepts of hedonism and eudaimonism, respectively. How these different views relate to each other and to WB as a whole has not yet been clearly defined, leading to difficulties in interpretation. In this review, we aim to get more insight into the relation between SWB and PWB. We first present an overview of the philosophical history of SWB and PWB, followed by a systematic literature review. The goal of this review, based on 29 studies, was to investigate how much evidence there is for a conceptual overlap between SWB and PWB. A majority of the studies found appreciable shared variance between the constructs, suggesting that they might be more closely related than previously assumed. On the other hand, evidence from biological studies provides mixed results: a distinction between SWB and PWB based on unique biomarkers is reported, while recent molecular genetic studies show strong genomic overlap between SWB and PWB, but different gene-expression regulation. We end with a discussion on how these findings fit into a well-being framework, and describe some of the issues in the well-being field as we encountered them in our review followed by potential solutions to these problems

The Effect of Mixed Wettability on Pore‐Scale Flow Regimes Based on a Flooding Experiment in Ketton Limestone

Darcy‐scale multiphase flow in geological formations is significantly influenced by the wettability of the fluid‐solid system. So far it has not been understood how wettability impacts the pore‐scale flow regimes within rocks, which were in most cases regarded as an alteration from the base case of strongly water‐wet conditions by adjustment of contact angles. In this study, we directly image the pore‐scale flow regime in a carbonate altered to a mixed‐wet condition by aging with crude oil to represent the natural configuration in an oil reservoir with fast synchrotron‐based X‐ray computed tomography. We find that the pore‐scale flow regime is dominated by ganglion dynamics in which the pore space is intermittently filled with oil and brine. The frequency and size of these fluctuations are greater than in water‐wet rock such that their impact on the overall flow and relative permeability cannot be neglected in modeling approaches.ISSN:0094-8276ISSN:1944-800

Design of COSMIC:a randomized, multi-centre controlled trial comparing conservative or early surgical management of incomplete cervical cord syndrome without spinal instability

<p>Background: Incomplete cervical cord syndrome without spinal instability is a very devastating event for the patient and the family. It is estimated that up to 25% of all traumatic spinal cord lesions belong to this category. The treatment for this type of spinal cord lesion is still subject of discussion. From a biological point of view early surgery could prevent secondary damage due to ongoing compression of the already damaged spinal cord. Historically, however, conservative treatment was propagated with good clinical results. Proponents for early surgery as well those favoring conservative treatment are still in debate. The proposed trial will contribute to the discussion and hopefully also to a decrease in the variability of clinical practice.</p><p>Methods/Design: A randomized controlled trial is designed to compare the clinical outcome of early surgical strategy versus a conservative approach. The primary outcome is clinical outcome according to mJOA. This also measured by ASIA score, DASH score and SCIM III score. Other endpoints are duration of the stay at a high care department (medium care, intensive care), duration of the stay at the hospital, complication rate, mortality rate, sort of rehabilitation, and quality of life. A sample size of 36 patients per group was calculated to reach a power of 95%. The data will be analyzed as intention-to-treat at regular intervals, but the end evaluation will take place at two years post-injury.</p><p>Discussion: At the end of the study, clinical outcomes between treatments attitudes can be compared. Efficacy, but also efficiency can be determined. A goal of the study is to determine which treatment will result in the best quality of life for the patients. This study will certainly contribute to more uniformity of treatment offered to patients with a special sort of spinal cord injury.</p>

Workflow for Upscaling Wettability from the Nanoscale to Core Scale

Wettability is a key factor influencing multiphase flow in porous media. In addition to the average contact angle, the spatial distribution of contact angles throughout the porous medium is important, as it directly controls the connectivity of wetting and nonwetting phases. The controlling factors may not only relate to the surface chemistry of minerals but also to their texture, which implies that a length-scale range from nanometers to centimeters has to be considered. So far, an integrated workflow addressing wettability consistently through the different scales does not exist. In this study, we demonstrate that such a workflow is possible by combining microcomputed tomography (mu CT) imaging with atomic-force microscopy (AFM). We find that in a carbonate rock, consisting of 99.9% calcite with a dual-porosity structure, wettability is ultimately controlled by the surface texture of the mineral. Roughness and texture variation within the rock control the capillary pressure required for initializing proper crude oil-rock contacts that allow aging and subsequent wettability alteration. AFM enables us to characterize such surface-fluid interactions and to investigate the surface texture. In this study, we use AFM to image nanoscale fluid-configurations in 3D at connate water saturation and compare the fluid configuration with simulations on the rock surface, assuming different capillary pressures

Workflow for upscaling wettability from the nanoscale to core scale

Wettability is a key factor influencing multiphase flow in porous media. In addition to the average contact angle, the spatial distribution of contact angles throughout the porous medium is important, as it directly controls the connectivity of wetting and nonwetting phases. The controlling factors may not only relate to the surface chemistry of minerals but also to their texture, which implies that a length-scale range from nanometers to centimeters has to be considered. So far, an integrated workflow addressing wettability consistently through the different scales does not exist. In this study, we demonstrate that such a workflow is possible by combining microcomputed tomography (mu CT) imaging with atomic-force microscopy (AFM). We find that in a carbonate rock, consisting of 99.9% calcite with a dual-porosity structure, wettability is ultimately controlled by the surface texture of the mineral. Roughness and texture variation within the rock control the capillary pressure required for initializing proper crude oil-rock contacts that allow aging and subsequent wettability alteration. AFM enables us to characterize such surface-fluid interactions and to investigate the surface texture. In this study, we use AFM to image nanoscale fluid-configurations in 3D at connate water saturation and compare the fluid configuration with simulations on the rock surface, assuming different capillary pressures

Fast X-Ray micro-CT study of the impact of brine salinity on the pore-scale fluid distribution during waterflooding

Many studies indicate that the recovery of crude oil by waterflooding can be improved by lowering the salinity of injected water. This so-called low-salinity effect (LSE) is often associated with the change of the wetting state of rock towards more water-wet. However, it is not very well understood how wettability alteration at the pore level could lead to an increase in production at the Darcy scale. Therefore, this study aims at direct observation of the wettability-change-driven fluid reconfiguration related to a lower-salinity (LS) flood at the pore-network scale, using synchrotron beamline-based fast X-ray computed tomography. Cylindrical outcrop rock samples were initialized by first saturating them with high-salinity (HS) brine, then displacing the HS brine with crude oil down to residual water saturation. After this initialization the rock samples were aged to establish wettability states assumed to be close to mixed-wet conditions. During the flooding experiments, the pore-scale fluid distribution was imaged at a voxel resolution of 3 µm and (under flowing conditions) a time resolution of 10 s for a full 3D image. The micro- CT flow experiments were conducted on both sandstone and carbonate rocks, all in tertiary mode and at identical field relevant flow rates. The real-time imaging shows the presence of an oil/water structure in addition to the oil and water phases and a saturation change during the HS waterflood which approaches a stable equilibrium at its end. During flow of both HS and LS brine we observe (re-)connection and disconnection of the oil phase which are characteristics of ganglion dynamics. In addition, we observe relatively slow pore-filling events that we believe to be characteristic of the mixed-wet state of the sample. Preliminary analysis indicates that upon lowering of injection brine salinity individual pores change fluid occupancy, however further research is required to draw definitive conclusions