Volume Deviation Research Articles

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties.

Antiplasticization of glassy polymers, arising from the addition of small amounts of plasticizer, was examined to highlight the developments that have taken place over the last few decades, aiming to fill gaps of knowledge in the large number of disjointed publications. The analysis includes the role of polymer/plasticizer molecular interactions and the conditions leading to the cross-over from antiplasticization to plasticization. This was based on molecular dynamics considerations of thermal transitions and related relaxation spectra, alongside the deviation of free volumes from the additivity rule. Useful insights were gained from an analysis of data on molecular glasses, including the implications of the glass fragility concept. The effects of molecular packing resulting from antiplasticization are also discussed in the context of physical ageing. These include considerations on the effects on mechanical properties and diffusion-controlled behaviour. Some peculiar features of antiplasticization regarding changes in Tg were probed and the effects of water were examined, both as a single component and in combination with other plasticizers to illustrate the role of intermolecular forces. The analysis has also brought to light the shortcomings of existing theories for disregarding the dual cross-over from antiplasticization to plasticization with respect to modulus variation with temperature and for not addressing failure related properties, such as yielding, crazing and fracture toughness.

Are Signs of Degenerative Joint Disease Associated With Chin Deviation?

Degenerative joint changes commonly affect the temporomandibular joint (TMJ) and can result in chin deviation. However, the extent of degenerative TMJ changes and chin deviation has not been well-characterized. The present study sought to correlate degenerative TMJ changes with condylar volume, grayscale measures, and chin deviation. The present cross-sectional study had enrolled women with skeletal Class III malocclusion. Cone-beam computed tomography scans were acquired preoperatively. For each condyle, degenerative TMJ signs were analyzed and the condylar volume and grayscale were measured. The predictor variable was the presence of degenerative TMJ signs, classified as categorical data: 0, if none; 1, only present in 1 joint; and 2, present in both joints. The primary outcome variable was a chin deviation of 3mm or more. Other associated variables were grouped by age, cephalometric data, and 3-dimensional condylar measurements. Descriptive bivariate statistics were computed, and univariate and multiple logistic regression analyses were conducted to identify any associations between degenerative TMJ disease and chin deviation. We included 85 patients, who were classified into 2 groups: less than 3mm of chin deviation (n=43) and 3mm or more of chin deviation (n=42). The presence of more than 10 degenerative TMJ signs was significantly associated with the presence of 3mm or more of chin deviation (P<.001). In multiple regression models, the presence of subcortical sclerosis in 1 joint and in both joints (adjusted odds ratio [OR], 3.698; 95% confidence interval [CI], 1.051 to 13.012; adjusted OR, 5.001; 95% CI, 1.461-17.119, respectively) correlated significantly with the presence of 3mm or more of chin deviation (P<.05). The volume difference between the 2 condyles was significantly greater in the group with more than 10 degenerative TMJ signs and 3mm or more of chin deviation than in the group with 10 or fewer degenerative TMJ signs and less than 3mm of chin deviation (P=.016 and P<.001, respectively). In women with skeletal Class III malocclusion, the presence of more than 10 degenerative TMJ signs increased the prevalence of 3mm or more of chin deviation. The presence of subcortical sclerosis in either 1 or both joints and volume differences between the 2 condyles were associated with greater chin deviation.

Анализ производства электроэнергии в Кыргызстане

This article provides a dynamic analysis of the volume of water accumulation in the Toktogul hydroelectric station, a variance analysis of the electricity production of the Kyrgyz Republic, as well as a dynamic analysis of electricity production. To analyze the trend of water accumulation, water volumes for twelve years were used. Using dynamic analysis, the deviation of the annual volume of water over 12 years is determined, and it deviates from the average annual level by 27.94%. The dynamic analysis method revealed that the production of electricity is unstable.

Impact of Peer Review in Reducing Uncertainty in the Definition of the Lung Target Volume Among Trainee Oncologists

AimsTo evaluate the impact of peer review and contouring workshops on reducing uncertainty in target volume delineation for lung cancer radiotherapy. Materials and methodsData from two lung cancer target volume delineation courses were analysed. In total, 22 trainees in clinical oncology working across different UK centres attended these courses with priori experience in lung cancer radiotherapy. The courses were made up of short presentations and contouring practice sessions. The participants were divided into two groups and asked to first individually delineate (IND) and then individually peer review (IPR) the contours of another participant. The contours were discussed with an expert panel consisting of two consultant clinical oncologists and a consultant radiologist. Contours were analysed quantitatively by measuring the volume and local distance standard deviation (localSD) from the reference expert consensus contour and qualitatively through visual analysis. Feedback from the participants was obtained using a questionnaire. ResultsAll participants applied minor editing to the contours during IPR, leading to a non-statistically significant reduction in the mean delineated volume (IND = 140.92 cm3, IPR = 125.26 cm3, P = 0.211). The overall interobserver variation was similar, with a localSD of 0.33 cm and 0.38 cm for the IND and IPR, respectively (P = 0.848). Six participants (29%) carried out correct major changes by either including tumour or excluding healthy tissue. One participant (5%) carried out an incorrect edit by excluding parts of the tumour, while another observer failed to identify a major contour error. The participants' level of confidence in target volume delineation increased following the course and identified the discussions with the radiologist and colleagues as the most important highlights of the course. ConclusionIPR could improve target volume delineation quality among trainee oncologists by identifying most major contour errors. However, errors were also introduced after IPR, suggesting the need to further discuss major changes with a multidisciplinary team.

Theoretical dependence of hardness on the structural parameters for hard and superhard ceramics

This study presents the results of a brief overview on hard and superhard ceramic materials, in particular the crystal lattice parameters and hardness. Their structural parameters were analyzed in order to determine a theoretical dependence describing the hardness changes. A parameter of an effective volume of crystal structure was proposed, which was considered along with the crystal lattice volume and two more indices, i.e. the coordination number and the structural factor. It was shown that the structural factor was determined both for simple substances and for crystals of chemical compounds in which polyatomic molecular complexes were present. A theoretical dependence based on the fundamental relationship between hardness and the deviation of the effective volume of the crystal structure was proposed.

Thermodynamic study of ester diethyl tartrate and its binary systems with iso-alcohols

Densities of pure ester diethyl tartrate and alcohols isobutanol and isopentanol are measured on high pressures up to 60 MPa and temperatures from 293.15 K to 413.15 K, while thermophysical properties for two systems ester + alcohol are obtained on atmospheric pressure and temperatures 288.15–323.15 K. High pressure densities were correlated with Tammann-Tait equation. Experimental data on atmospheric pressure for mixtures were used to determine derived properties, excess molar volume, viscosity and refractive index deviations, which are then correlated with Redlich-Kister polynomial equation. To support the discussion regarding interactions, FT-IR analyses of pure components and mixtures with highest absolute values of excess molar volume were presented. Additionally, viscosity modelling was performed with predictive and correlative models and results were discussed from the point of potential usage of applied models to calculate viscosity of investigated systems.

Fluid volumes infused during burn resuscitation 1980–2015: A quantitative review

Introduction‘Fluid creep’ or excessive fluid delivered to burn patients during early resuscitation has been suggested by several studies from individual burn centers. MethodsWe performed a Medline search from 1980 to 2015 in order to identify studies of burn patients predominantly resuscitated with lactated Ringers with infusion adjusted per urinary output. Data was abstracted for 48 publications (3196 patients) that met entry criteria. ResultsHigher resuscitation volumes compared to Parkland estimates were reported, but the trend of increasing resuscitation volumes over the last 30 years is not supported by regression of total fluid infused versus year of study. Mean 24h fluid infused for all studies was 5.2±1.1mL/kg per %TBSA. The mean 24h urinary output reported in 30 studies was 1.2±0.5mL/kg per hr. Burns with inhalation injuries (5 studies) received significantly more fluid than non-inhalation injured burn patients (5.0±1.3 versus 3.9±0.9mL/kg per %TBSA). Fluid infused and urinary outputs were similar for adults and pediatric patients. The most striking finding of our analyses was the great ranges of the means and high standard deviations of volumes infused compared to the original Baxter publication that introduced the Parkland formula ConclusionsThese analyses suggest that burn units currently administer volumes larger than Parkland formula with great patient variability. Individual patient hourly data is needed to better understand the record of burn resuscitation and Fluid Creep.

Unit cell parameters of 32S8 – 34S8 solid mixtures and their extremal behavior

The behavior of isotopic mixtures of polyatomic molecular compounds can have a critical character. Orthorhombic sulfur α-S8 is a typical representative of polyatomic molecular compounds among simple substances. Samples comprised of orthorhombic sulfur of different 32S and 34S ratio have been prepared and examined with powder X-Ray diffractometry in the temperature region from −100 to +90 °С. Unit cell parameters of sulfur samples with intermolecular isotopic substitution, containing 0.4 to 0.5 parts of 34S8 molecules, differ radically from the samples of the isotopic composition close to pure α-32S8 and α-34S8. Maximal deviation of unit cell volume −0.17% at −100.0 °C is observed for the sample with a part of 34S8 molecules being 0.45. Such a behavior could well be attributed to the ordering between 32S8 and 34S8 molecules in the crystal that can be triggered by lowering temperature.

Intrinsic and Dual Volume Deviations of Convex Bodies and Polytopes

AbstractWe establish estimates for the asymptotic best approximation of the Euclidean unit ball by polytopes under a notion of distance induced by the intrinsic volumes. We also introduce a notion of distance between convex bodies that is induced by the Wills functional and apply it to derive asymptotically sharp bounds for approximating the ball in high dimensions. Remarkably, it turns out that there is a polytope that is almost optimal with respect to all intrinsic volumes simultaneously, up to absolute constants.Finally, we establish asymptotic formulas for the best approximation of smooth convex bodies by polytopes with respect to a distance induced by dual volumes, which originate from Lutwak’s dual Brunn–Minkowski theory.

Classification of tight sandstone reservoirs based on NMR logging

The traditional reservoir classification methods based on conventional well logging are inefficient for determining the properties, such as the porosity, shale volume, J function, and flow zone index, of the tight sandstone reservoirs because of their complex pore structure and large heterogeneity. Specifically, the method that is commonly used to characterize the reservoir pore structure is dependent on the nuclear magnetic resonance (NMR) transverse relaxation time (T2) distribution, which is closely related to the pore size distribution. Further, the pore structure parameters (displacement pressure, maximum pore-throat radius, and median pore-throat radius) can be determined and applied to reservoir classification based on the empirical linear or power function obtained from the NMR T2 distributions and the mercury intrusion capillary pressure curves. However, the effective generalization of these empirical functions is difficult because they differ according to the region and are limited by the representative samples of different regions. A lognormal distribution is commonly used to describe the pore size and particle size distributions of the rock and quantitatively characterize the reservoir pore structure based on the volume, mean radius, and standard deviation of the small and large pores. In this study, we obtain six parameters (the volume, mean radius, and standard deviation of the small and large pores) that represent the characteristics of pore distribution and rock heterogeneity, calculate the total porosity via NMR logging, and classify the reservoirs via cluster analysis by adopting a bimodal lognormal distribution to fit the NMR T2 spectrum. Finally, based on the data obtained from the core tests and the NMR logs, the proposed method, which is readily applicable, can effectively classify the tight sandstone reservoirs.

A multi-objective and multi-scenario optimization model for operation control of CO2-flooding pipeline network system

Abstract Countries with high carbon emissions are actively exploring carbon capture, utilization and storage (CCUS) system. CCUS-based CO2 enhanced oil recovery (CO2-EOR) technology is favored for sustainable oilfield development and its contribution to mitigating global warming. In this paper, under the crafts constraints of injection stations and CO2-flooding wells, as well as the flow rate and pressure constraints along pipeline network, a multi-objective mixed integer nonlinear programming (MOMINLP) model is proposed for the optimal operation control of oilfield surface CO2-flooding pipeline network system. The minimum operating costs of pumps, the maximum CO2 injection volume and the minimum demand-injection volume deviation are set as objective functions. The uncertainty of demand CO2 injection volume caused by geological uncertainty is settled by scenario-based stochastic programming method. In addition, the piecewise linearization method and the augmented e-constraint method (AUGMECON) are introduced to deal with the nonlinear constraints and get the Pareto optimal solutions, respectively. Finally, the proposed model is successfully applied to a large-scale looped and branched CO2-flooding pipeline network system in Sinkiang, China with three cases for comparison to verify its applicability and superiority.

Modeling forest management effects on water and sediment yield from nested, paired watersheds in the interior Pacific Northwest, USA using WEPP

The Water Erosion Prediction Project (WEPP) model was applied to seven paired, nested watersheds within the Mica Creek Experimental Watershed located in northern Idaho, USA. The goal was to evaluate the ability of WEPP to simulate the direct and cumulative effects of clear-cutting and partial-cutting (50% canopy removal) on water and sediment yield. WEPP was modified to better represent changes in the Leaf Area Index during post-harvest forest vegetative recovery. Good agreement between simulated and observed streamflow was achieved with minimal to no calibration over a 16-year (1992–2007) period. For the seven watersheds and the entire study period, the overall Nash-Sutcliffe Efficiency (NSE), Kling-Gupta efficiency (KGE), and deviation of runoff volume (DV) between observed and simulated daily streamflow ranged 0.58–0.71, 0.67–0.81, and −4% to 9%, respectively. Good agreement between predicted and observed suspended sediment yield was achieved through the calibration of a single channel critical shear stress parameter. For sediment yield, NSE, KGE, and DV ranged 0.62–0.97, 0.43–0.97, and −2% to 2%, respectively, for the calibration period, and 0.61–0.93, 0.42–0.95, and −24% to 13%, respectively, for the period of model performance assessment. Regression analysis of observed- and WEPP-simulated increase in water and sediment yield following clear-cut treatment was similar; however, the WEPP-simulated increase was lower compared to observations particularly from the partial-cut watershed. The variability in the critical shear parameter for different stream channels in the study watersheds was directly related to the observed mean particle size on the stream bed and suggests that applications of the WEPP model in ungauged basins could potentially set the critical shear parameter based on particle size. Overall, the simulated results demonstrate the potential of WEPP as a modeling tool for forestland watershed management, particularly for estimating the effects of forest harvest on hydrograph fluctuations and consequently, stream sediment transport.

Effect of Early vs Delayed Activation of Thoracic Epidural Anesthesia on Plasma Pro-Atrial Natriuretic Peptide to Indicate Deviations in Central Blood Volume during Esophagectomy

Effect of Early vs Delayed Activation of Thoracic Epidural Anesthesia on Plasma Pro-Atrial Natriuretic Peptide to Indicate Deviations in Central Blood Volume during Esophagectomy

Characterization of differential throughfall drop size distributions beneath European beech and Norway spruce

AbstractForest canopies present irregular surfaces that alter both the quantity and spatiotemporal variability of precipitation inputs. The drop size distribution (DSD) of rainfall varies with rainfall event characteristics and is altered substantially by the forest stand properties. Yet, the influence of two major European tree species, European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H. Karst), on throughfall DSD is largely unknown. In order to assess the impact of these two species with differing canopy structures on throughfall DSD, two optical disdrometers, one above and one below the canopy of each European beech and Norway spruce, measured DSD of both incident rainfall and throughfall over 2 months at a 10‐s resolution. Fractions of different throughfall categories were analysed for single‐precipitation events of different intensities. While penetrating the canopies, clear shifts in drop size and temporal distributions of incoming rainfall were observed. Beech and spruce, however, had different DSD, behaved differently in their effect on diameter volume percentiles as well as width of drop spectrum. The maximum drop sizes under beech were higher than under spruce. The mean ± standard deviation of the median volume drops size (D50) over all rain events was 2.7 ± 0.28 mm for beech and 0.80 ± 0.04 mm for spruce, respectively. In general, there was a high‐DSD variability within events indicating varying amounts of the different throughfall fractions. These findings help to better understand the effects of different tree species on rainfall partitioning processes and small‐scale variations in subcanopy rainfall inputs, thereby demonstrating the need for further research in high‐resolution spatial and temporal properties of rainfall and throughfall.

Influence of the Accuracy of Intraoral Scanbodies on Implant Position: Differences in Manufacturing Tolerances.

To assess the manufacturing tolerances of three different intraoral scanbodies (ISBs) and their possible influence on the transfer of the intraoral implant position to the digital cast. Three different ISBs were measured using x-ray computed tomography. The length, diameter, angle, and target volume deviation were analyzed, and the data were subjected to a univariate analysis of variance. There were significant differences between all three ISBs in length, diameter, and target volume deviations (P < .05). Manufacturing tolerances of ISBs have the potential to decisively affect the transfer accuracy of the implant position from the recorded intraoral position to the digital cast, which needs to be considered.

Use of Constants of Carbon and Ultrahigh-Molecular-Weight Polyethylene Fiber for Calculation of Density of Unidirectional Composites

A method making it possible to calculate the density and matrix volume fraction of two-component and hybrid composites reinforced with unidirectional rovings of carbon fibers (CF) and ultrahigh-molecular-weight polyethylene (UHMWPE) fibers is presented. Experimentally found constants of the rovings were used in calculation. The values of calculated density and matrix volume fraction were compared with an actual data of samples. The samples were obtained by resin impregnation of the rovings at free air. The impregnation was implemented simultaneously with laying of the rovings. This procedure does not permit saving the prespecified sample volume without volume control. The effects of volume deviations on the actual density of sample and the actual volume fraction of matrix were investigated on the samples with uncontrolled and controlled volume. The roving volume fractions and concentrations of hybrid and two-component composites were specified as the basic data of calculations. The actual densities of samples, as well as the value of matrix volume fractions, were compared with the calculated ones. The experimental data are in good agreement with the calculated data.

Influence of alcohols on the inter-ion interactions in ionic liquids: A molecular dynamics study

Despite a growing number of research reports on neat room temperature ionic liquids (RTILs) and their mixtures with molecular solvents in recent years, understanding and rationalising of such systems is still a challenge. In this work, we performed a classical molecular dynamics simulation study of the pure components - 1-ethyl-3-methylimidazolium thiocyanate (C2C1imSCN), methanol, and ethanol - and their binary mixtures at room temperature. Thermodynamic (density and heats of vaporization), transport (viscosity and self-diffusion coefficients) and structural (in terms of radial, angular and spatial distributions) properties were analysed. It was found, that with the decrease of RTIL content, the ions self-diffusion coefficients notably increase, reaching higher values in the C2C1imSCN-MeOH system. Density and viscosity follow the opposite trend, reaching their minimum at lower RTIL mole fraction. Negative deviations of excess molar volume from ideality in the studied mixtures with minima at ~ 0.2–0.3 mole fraction of RTIL suggest the strongest ion-molecular interactions at this mixture composition. A careful analysis at the molecular level revealed that introducing of alcohols to both systems weakens the inter-ionic H-bonding network, particularly, at low RTIL content. The cation-cation arrangement was found to lose its characteristic above/below orientation in neat RTIL and become disordered at low RTIL content. As to the tail length of the selected alcohols, this was found to have an insignificant effect on the structural properties of the addressed systems.

Orbital floor symmetry after maxillectomy and orbital floor reconstruction with individual titanium mesh using computer-assisted navigation

The present study aimed to evaluate the symmetry of the orbital floor after maxillectomy and orbital floor reconstruction with individual titanium mesh using a computer-assisted navigation system. Nineteen patients who underwent orbital floor reconstruction with individual titanium mesh were included in this study. Postoperative computed tomography scans recorded after three-dimensional (3D) reconstruction were used to evaluate the symmetry of the orbital floor, including orbital floor height, orbital floor eminence, globe projection, orbital volume, and surface deviation. The average orbital floor height of the reconstructed and the unaffected side was 37.7 ± 2.3 and 37.8 ± 2.7 mm, respectively (P=.47). The average orbital floor eminence of the reconstructed and the unaffected side was 40.1 ± 5.5 and 39.6 ± 5.3 mm, respectively (P=.17). The average globe projection of the reconstructed and the unaffected side was 15.5 ± 3.2 and 15.3 ± 3.0 mm, respectively (P=.27). The average orbital volume of the reconstructed and the unaffected side was 25.9 ± 4.4 and 26.3 ± 4.4cm3, respectively (P=.29). Repeatability between the reconstructed and the unaffected side was 88.3%±2.6% at within 1 mm and 98.6%±0.9% at within 2 mm. The average of maximum deviation was 2.4 ± 0.2 mm. Individual titanium mesh is one of the best techniques for orbital floor reconstruction, as it can be placed precisely and helps achieve desirable esthetic outcomes through virtual surgical planning and using a computer-assisted navigation system.

Investigating hydrologic responses to spatio‐temporal characteristics of storms using a Dynamic Moving Storm generator

AbstractA synthetic storm generator—Dynamic Moving Storm (DMS)—is developed in this study to represent spatio‐temporal variabilities of rainfall and storm movement in synthetic storms. Using an urban watershed as the testbed, the authors investigate the hydrologic responses to the DMS parameters and their interactions. In order to reveal the complex nature of rainfall–run‐off processes, previously simplified assumptions are relaxed in this study regarding (a) temporal variability of rainfall intensity and (b) time‐invariant flow velocity in channel routing. The results of this study demonstrate the significant contribution of storm moving velocity to the variation of peak discharge based on a global sensitivity analysis. Furthermore, a pairwise sensitivity analysis is conducted to elucidate not only the patterns in individual contributions from parameters to hydrologic responses but also their interactions with storm moving velocity. The intricacies of peak discharges resulting from sensitivity analyses are then dissected into independent hydrologic metrics, that is, run‐off volume and standard deviation of run‐off timings, for deeper insights. It is confirmed that peak discharge is increased when storms travel downstream along the main channel at the speed that corresponds to a temporal superposition of run‐off. Spatial concentration of catchment rainfall is found to be a critical linkage through which characteristics of moving storms affect peak discharges. In addition, altering peak timing of rainfall intensity in conjunction with storm movement results in varied storm core locations in the channel network, which further changes the flow attenuation effects from channel routing. For future directions, the DMS generator will be embedded in a stochastic modelling framework and applied in rainfall/flow frequency analysis.

Effect of early versus delayed activation of thoracic epidural anesthesia on plasma pro-atrial natriuretic peptide to indicate deviations in central blood volume during esophagectomy

Background and ObjectivesA side effect to thoracic epidural anesthesia (TEA) is hypotension induced by central hypovolemia. This study addressed whether early activation (EA) versus late activation (LA) of TEA affects...