Mixed Volume Research Articles

A Mixed Volume Element Modified With Characteristic Fractional Step Difference Method for the Compressible Multicomponent Displacement and Its Numerical Analysis

A three-dimensional compressible problem with different components is fundamental in numerical simulation of enhanced oil recovery. The mathematical model consists of a parabolic equation for the pressure and a convection-diffusion system for the concentrations. The pressure determines Darcy velocity and plays an important role during the whole physical process. A conservative mixed volume element is used to discretize the flow equation, and improves the computational accuracy of Darcy. The concentrations are computed by the modified characteristic fractional step difference scheme, thus numerical dispersion and nonphysical oscillations are eliminated. The whole three-dimensional computation is accomplished effectively by solving three successive one-dimensional problems in parallel, where the speedup method is used and the work is decreased greatly. Based on the theory and special techniques of a priori estimates of partial differential equations, an optimal second error estimates in L^2-norm is concluded. This work concentrates on the model, numerical method and convergence analysis for modern oil recovery.

The HEV Ventilator: at the interface between particle physics and biomedical engineering.

A high-quality, low-cost ventilator, dubbed HEV, has been developed by the particle physics community working together with biomedical engineers and physicians around the world. The HEV design is suitable for use both in and out of hospital intensive care units, provides a variety of modes and is capable of supporting spontaneous breathing and supplying oxygen-enriched air. An external air supply can be combined with the unit for use in situations where compressed air is not readily available. HEV supports remote training and post market surveillance via a Web interface and data logging to complement standard touch screen operation, making it suitable for a wide range of geographical deployment. The HEV design places emphasis on the ventilation performance, especially the quality and accuracy of the pressure curves, reactivity of the trigger, measurement of delivered volume and control of oxygen mixing, delivering a global performance which will be applicable to ventilator needs beyond the COVID-19 pandemic. This article describes the conceptual design and presents the prototype units together with a performance evaluation.

Mixed Convection Flow of Magnetized Casson Nanofluid over a Cylindrical Surface

This work aimed to establish a numerical simulation of kerosene oil as a host Casson fluid flowing around a cylindrical shape with an applied magnetic field crossing through it, under constant wall temperature boundary conditions. Nanoparticles of zinc, aluminum, and titanium oxides were included to reinforce its thermal characteristics. The governing model was established based on the Tiwari and Das model. Graphical and numerical results for correlated physical quantities were gained through the Keller Box method, with the assistance of MATLAB software (9.2). The combined convection (λ>0 & λ<0), magnetic parameter (M>0), Casson parameter (β>0), and nanosolid volume fraction (0.1≤χ≤0.2) were the parameter ranges considered in this study. According to the current findings, the growth of mixed convection parameter or volume fraction of ultrafine particles contributes to boosting the rate of energy transport, skin friction, and velocity distribution. Zinc oxide–kerosene oil has the highest velocity and temperature, whatever the parameters influencing it.

Agitation of yield stress fluids by gas injection

AbstractThis study is in line with two previous studies by the same authors on gas injection in yield stress fluids. Gas is injected toward the bottom wall of a prismatic tank containing a yield stress fluid. When rising toward the free surface, trains of bubbles generate fluid recirculation in the tank. Two experimental colorimetric methods are introduced and validated in order to quantify the recirculation liquid flow rate as well as the time evolution of the extent and shape of the mixed volume. The influences of the injection flow rate, fluid rheology, and reactor size have been quantified. Correlations based on the characteristic nondimensional numbers of the flow have been developed to predict the downward liquid flow rate as well as the mixed volume. A model for estimating the mixing time is also developed and compared to experimental results.

Strength and Durability of Recycled Concrete Strengthened with Steel Fibers and Styrene Butadiene Rubber Latex

Demolition of any structure is costly, and simultaneously there is non-accessibility of land or disposal sites in nearby areas. Recycling such demolished concrete material and converting it into an appropriate size of aggregates can be further used for the following construction cycle. Prior exploration showed utilization of Steel Fibers (SF) and Styrene Butadiene Rubber (SBR) latex in Recycled Concrete (RC) independently for various strength and durability improvements. This experimental work cast RC as M25 & M40 grade to satisfy reinforced concrete and rigid concrete pavement concrete demand. Total 132 cubes, 198 cylinders, and 198 beams of Normal Concrete (NC), RC, and RC reinforced by SF with SBR latex cast and termed as Polymer Modified Steel Fiber Reinforced Recycled Concrete (PMSFRRC). The objective was to evaluate the properties due to SF and SBR latex blending and obtaining the optimum dosages of SF and SBR latex. A strength and durability study was carried out to find out cube compressive strength, indirect tensile strength, flexural strength, chloride attack, and sulfate attack. The concrete was modified with the SBR latex dosage range of 2.5% –7.5% by cement weight. SF was added as 0.5% – 1.5% by concrete mix volume at the average length of 25 mm and 0.5 mm in diameter. Experimental findings of PMSFRRC for grade M25 with SF 1% volume fraction of concrete and SBR latex 5% of cement weight improve NC in indirect tensile strength by 9.93% and 8.58%, flexural strength by 10.01% and 8.99% at 28 and 91 days, respectively. Similarly, there was an enhancement in indirect tensile strength by 13.18 % and 11.11 % and flexural strength by 12.88 % and 10.78 % at 28 and 91 days, respectively, for PMSFRRC of grade M40 compared to NC. Durability analysis shows that a combined dosage of SF 1.5% volume of concrete mix and SBR latex 7.5% of cement weight seemed to be excellent concrete additives for good resistance to acid and sulfate attack for both mixtures. The results exhibited improved hardened properties of modified concrete due to the combined addition of SF and SBR latex, improved cracking resistance, flexure resistance, and reduced acid and sulfate attack rate into the specimens. The study also demonstrated an effective way of preparing sustainable concrete with SF and SBR latex to improve strength and durability.

A two-grid mixed finite volume element method for nonlinear time fractional reaction-diffusion equations

<abstract><p>In this paper, a two-grid mixed finite volume element (MFVE) algorithm is presented for the nonlinear time fractional reaction-diffusion equations, where the Caputo fractional derivative is approximated by the classical $ L1 $-formula. The coarse and fine grids (containing the primal and dual grids) are constructed for the space domain, then a nonlinear MFVE scheme on the coarse grid and a linearized MFVE scheme on the fine grid are given. By using the Browder fixed point theorem and the matrix theory, the existence and uniqueness for the nonlinear and linearized MFVE schemes are obtained, respectively. Furthermore, the stability results and optimal error estimates are derived in detailed. Finally, some numerical results are given to verify the feasibility and effectiveness of the proposed algorithm.</p></abstract>

The Correlation of the Heat Conduction of Pulse-Heated Solution with Its Mixing Volume

The Correlation of the Heat Conduction of Pulse-Heated Solution with Its Mixing Volume

Concurrent WIP and an application to clearing functions for complex heterogenous systems

Complex manufacturing systems are challenging to study because of the high level of information required and the inaccessibility of most of it. Their tractability is however essential for the efficiency of state-of-the-art industries. This is particularly the case in the semiconductor industry that faces high mix and low volume conditions, and for which traditional methods fail to capture the high complexity and require continuous actions and corrections to adjust to heterogeneous toolsets and product-mix.We present the Concurrent WIP (CWIP), a new way of studying such systems at the level of a process-cluster by identifying each job's queue from its own perspective. CWIP is designed to be practical, with a low level of resource investments, yet informative. We explain how CWIP can be computed based on historical data and then used to derive capacity estimates and clearing functions without any assumptions on the system or on the form of the functions. In the process, we derive not only an average workload-dependent capacity, but also a confidence interval on this capacity. The relevance and efficiency of the proposed estimates are experimentally tested on a simulated system mimicking a small but complex process-cluster of the semiconductor industry. The estimates are used to predict WIP absorption times and we show how they characterize well not only the average behavior but also the full range of possible behaviors of the system. Finally, we discuss further applications of CWIP, that could be used to compute refined clearing functions or to monitor complex systems.

First-principles calculations of bulk, surface and interfacial phases and properties of silicon graphite composites as anode materials for lithium ion batteries.

The high energy density offered by silicon along with its mineralogical abundance in the earth's crust, make silicon a very promising material for lithium-ion-battery anodes. Despite these potential advantages, graphitic carbon is still the state of the art due to its high conductivity and structural stability upon electrochemical cycling. Composite materials combine the advantages of silicon and graphitic carbon, making them promising materials for the next generation of anodes. However, successfully implementing them in electric vehicles and electronic devices depends on an understanding of the phase, surface and interface properties related to their performance and lifetime. To this end we employ electronic structure calculations to investigate crystalline silicon-graphite surfaces and grain boundaries exhibiting various orientations and degrees of lithiation. We observe a linear relationship between the mixing enthalpies and volumes of both Li-Si and Li-C systems, which results in an empirical relationship between the voltage and the volume expansion of both anode materials. Assuming thermodynamic equilibrium, we find that the lithiation of graphite only commences after LixSi has been lithiated to x = 2.5. Furthermore, we find that lithium ions stabilize silicon surfaces, but are unlikely to adsorb on graphite surfaces. Finally, lithium ions stabilize silicon-graphite interfaces, increasing the likelihood of adhesion as core@shell over yolk@shell configurations with increasing degree of lithiation. These observations explain how lithium might accelerate the crystallization of silicon-graphite composites and the formation of smaller nanoparticles with improved performance.

Crofton Formulae for Products

It is shown how new integral-geometric formulae can be obtained from the existing formulae of Crofton type. In particular, for classical Crofton formulae in which the answer depends on the Riemannian volume, we obtain generalizations in terms of the mixed Riemannian volume defined in the paper. The method is based on the calculations in the ring of normal densities constructed in the previous work of the authors.

Apparent molar volume anomaly in water-dimethyl sulfoxide liquid mixtures. Molecular dynamics computer simulations

We have studied the composition dependence of density of liquid water-DMSO mixtures at different temperatures by using the isobaric-isothermal (NPT) molecular dynamics computer simulations. The non-polarizable semi-flexible, P1 and P2 models for the DMSO molecule combined with the TIP4P-2005 water model are considered. The excess mixing volume and the apparent molar volumes of the species are reported. We have established that the P1-TIP4P-2005 model for the mixture provides a very good description of the location of the minimum of apparent molar volume for DMSO species indicating the anomaly. Most important is that the temperature interval where the hydrophobic effect exists, is correctly captured with this modelling, in contrast to the P2-TIP4P-2005 model.

Revisiting the composition dependence of the properties of water-dimethyl sulfoxide liquid mixtures. Molecular dynamics computer simulations

We have revisited the composition dependence of principal properties of liquid water-DMSO mixtures by using the isobaric-isothermal molecular dynamics computer simulations. A set of non-polarizable semi-flexible models for the DMSO molecule combined with the TIP4P-2005 and TIP4P/ε water models is considered. We restrict calculations to atmospheric pressure, 0.1013 MPa, and room temperature, 298.15 K. Composition trends of density, excess mixing volume and excess mixing enthalpy, partial molar volumes and partial molar enthalpies of species, apparent molar volumes are reported. Besides, we explore composition trends of the self-diffusion of species, the static dielectric constant and the surface tension. Evolution of the microscopic structure of the mixture with composition is analyzed in terms of radial distributions functions, coordination numbers and the fractions of hydrogen-bonded molecules. We intend to capture the peculiarities of mixing the species in the mixture upon the DMSO molar fraction and the anomalous behaviors, if manifested in each of the properties under study. The quality of several combinations of the models for species is evaluated in detail to establish the possibility of necessary improvements.

HSI-Mixer: Hyperspectral Image Classification Using the Spectral–Spatial Mixer Representation From Convolutions

Transformer networks have shown impressive performance for hyperspectral interpretation. Nevertheless, the high-dimensional redundant spectral distribution of hyperspectral images (HSIs) hinders their validity of interaction between features from distant locations. In this letter, we propose the HSI-Mixer, a novel extremely simple convolution neural network (CNN), which is similar in spirit to Transformer to re-consider the remarkable inductive biases of convolutions. In specific, we construct a hybrid measurement-based linear projection (HMLP) to merge spectral signatures and spatial positions of an HSI cuboid. Meanwhile, according to the merging relations between spectral-spatial attributes, we establish both spectral and spatial Mixer blocks to separate features from a mixed volume to a pure one, across either spectral bands or spatial locations, respectively. Furthermore, our HSI-Mixer maintains the same-depth-and-resolution throughout the network. Experimental results on three benchmark datasets demonstrate that our proposal achieves promising performance, in contrast to other state-of-the-art methods. The codes of this work will be available at https://github.com/Blueseatear/IEEE_GRSL_2022_HSI-Mixer.

Correction to: Deep mixed ocean volume in the Labrador Sea in HighResMIP models

Correction to: Deep mixed ocean volume in the Labrador Sea in HighResMIP models

The functional form of the dual mixed volume

This paper is to generalize the dual mixed volume of star bodies to that of dual quasi-concave functions by extending the radial Minkowski linear combination of star bodies to that of dual quasi-concave functions. We attempt to build up some functional versions of notions and inequalities from the dual Brunn-Minkowski theory. In particular, both the dual mixed Brunn-Minkowski inequality of star bodies and the dual Aleksandrov Fenchel inequality of star bodies are generalized to that of dual quasi-concave functions.

The Lp-mixed quermassintegrals for 0 < p < 1

Abstract In the paper, Lp-harmonic addition, p-harmonic Blaschke addition and Lp-dual mixed volume are improved. A new p-harmonic Blaschke mixed quermassintegral is introduced. The relationship between p-harmonic Blaschke mixed volume and Lp-dual mixed volume is shown.

Duality Solutions in Hydromagnetic Flow of SWCNT-MWCNT/Water Hybrid Nanofluid over Vertical Moving Slender Needle

Recently, the topic of convection of heat transfer has created an interest among researchers because of its numerous applications in the daily life. The objective of this paper was to study theoretically the problem of mixed convection boundary layer flow and heat transfer of single-wall carbon nanotube (SWCNT) and multi-wall carbon nanotube (MWCNT) in presence of hydromagnetic effects. The problem was initiated by formulating a mathematical model in partial differential equation (PDE) for the hybrid nanofluid flow with appropriate boundary conditions. The similarity equation was used to transform the PDE into an ordinary differential equation (ODE) and solved using bvp4c in MATLAB. The graphical results on variation of skin friction coefficient, Cf, local Nusselt number, Nux, shear stress, f″c and local heat flux, −θ′c with the effects of magnetic, M, size of needle, c, mixed convection parameter, λ and volume fraction of nanoparticles, φ were presented and discussed in detail. The study revealed that duality of solutions appears when the buoyance force is in opposing flow of the fluid motion, λ<0. The presence of M in hybrid nanofluid reduced the skin friction coefficient and heat transfer. On the other hand, the Cf and Nux increased as different concentrations of φ1 and c were added. It gives an insight into the medical field, especially in treating cancer cells. By means, it reveals that CNTs hybrid nanofluid shows high potential in reaching the site of tumors faster compared with nanofluid. A stability analysis has to be carried out. It is noticed that the first solution was stable and physically realizable.

Distribution of Genomic Testing Resources by Oncology Practice and Rurality: A Nationally Representative Study.

Oncologists are increasingly using molecular profiling to inform personalized patient treatment decisions. Despite its promising utility, the integration of genomic testing into diverse clinical health care settings across geographic settings has been understudied. We used data from the National Survey of Precision Medicine in Cancer Treatment, a nationally representative sample of practicing US oncologists, to assess the availability of six genomic testing resources, including on-site pathology, contracts with outside laboratories, on-site genetic counselors, internal policies or protocols for using genomic and biomarker testing, electronic medical record alerts, and genomic or molecular tumor boards. We used multivariate logistic regression models to examine differences in the availability of each genomic testing resource by practice type and rurality while adjusting for payer mix and patient volume. A larger proportion of multispecialty group and academic practices had genomic testing resources available compared with solo and nonacademic practices. Electronic medical record alerts were the least available resource, whereas contracts with outside laboratories were the most available resource. Compared with urban practices, there were significantly fewer practices located in rural areas that had on-site pathology, on-site genetic counselors, protocols for genomic tests, and molecular tumor boards. Genomic testing resources varied by practice type and geography among a nationally representative sample of practicing oncologists. This variation has important implications for the development of interventions and policies to support the more equitable delivery of precision oncology to patients with cancer.

Strontium Aluminate Compound as Road Line Materials Application

Road line marking are used as a mean of controlling traffic and road user safety. It is very significant on any roads and intersections as they promote road safety. They highlight a harmonious flow of traffic along guided paths of travel. The objectives of this study are to investigate the properties of road line materials and examine the illuminance properties of glow in the dark powder applied in road marking materials. The use of photoluminescent glow-in-the-dark material was tested in the lab for its suitability (luminosity and the glow duration). The methods involved are selection of suitable type of glow in the dark materials, selection of optimum mixing ratio of the glow in the dark powder with thermoplastic powder, and finally analyzed for the properties of the type of the material chosen. The fine granular strontium aluminate compound, SrAl2O4 was selected as the most suitable type of glow in the dark material. Based on the laboratory analysis, the optimum ratio of the glow in the dark material to be used with thermoplastic powder is 55% of total mix volume. The average visible light emission period is in acceptable range of 20 m. This is a suitable distance to implement the road line because of the high visibility on the road during dark or night.

Numerical Simulation of Combustion of Natural Gas Mixed with Hydrogen in Gas Boilers

Hydrogen mixed natural gas for combustion can improve combustion characteristics and reduce carbon emission, which has important engineering application value. A casing swirl burner model is adopted to numerically simulate and research the natural gas hydrogen mixing technology for combustion in gas boilers in this paper. Under the condition of conventional air atmosphere and constant air excess coefficient, the six working conditions for hydrogen mixing proportion into natural gas are designed to explore the combustion characteristics and the laws of pollution emissions. The temperature distributions, composition, and emission of combustion flue gas under various working conditions are analyzed and compared. Further investigation is also conducted for the variation laws of NOx and soot generation. The results show that when the boiler heating power is constant, hydrogen mixing will increase the combustion temperature, accelerate the combustion rate, reduce flue gas and CO2 emission, increase the generation of water vapor, and inhibit the generation of NOx and soot. Under the premise of meeting the fuel interchangeability, it is concluded that the optimal hydrogen mixing volume fraction of gas boilers is 24.7%.