Critical Diameter Research Articles

Discovery of a new criterion for predicting glass-forming ability based on symbolic regression and artificial neural network

Metallic glasses (MGs) are widely used in various fields due to their superior physical properties. Glass-forming ability (GFA) represents the difficulty of forming MGs. Therefore, understanding and establishing the connection between materials characteristics and GFA is a great challenge in MGs research. In this work, to generate a new criterion to characterize GFA, symbolic regression and artificial neural network (ANN) were employed built on 7795 pieces of data. A completely new criterion was proposed and revealed the relationship between three characteristic temperatures (wherein Tg is the glass transition temperature, Tx is the onset crystallization temperature, and Tl is the liquidus temperature) and GFA. The new criterion not only exhibits a higher correlation to the critical casting diameter (Dmax) than the other 11 reported criteria but also illustrates the importance of high power (Tx − Tg)/(Tl − Tx) in characterizing GFA. Moreover, to test the criterion on unreported data, three models that can, respectively, perform GFA classification, predict Dmax, and three characteristic temperatures were built through artificial neural networks. Then, 439 new data generated by the ANN model were generated by models applied on Zr–Co–Al–X (X = W, Si, and Ni) alloys. On the testing data, the new criterion shows stronger generalization than other criteria, which proves its reliability and effectiveness.

Screening adsorbent-working solution pairs for adsorption-driven osmotic heat engines based on experimental water adsorption isotherm database and machine learning

Osmotic heat engines have attracted increasing attention in harvesting ultra-low temperature waste heat. In order to fill the gap in the high-throughput computational screening of adsorbent-aqueous salt solution working pairs for adsorption-driven osmotic heat engines, an experimental water adsorption isotherm database is constructed and eight common salt-water solutions are selected to identify the high-performance work pairs with system energy efficiency as evaluation indicator. The relationship between adsorbent properties, adsorbent structure characteristics and system performance is systematically analyzed. Results revealed that high working capacity and moderate adsorption enthalpy of adsorbents and large osmotic coefficients of salts are beneficial to energy efficiency. Adsorbents with larger accessible surface area, moderate available pore volume and critical pore diameter are favorable. Furthermore, regression machine learning is employed for achieving fast and accurate prediction of the system energy efficiency to accelerate screening. Genetic algorithm is adopted to search for the best-performing working pair properties.

ADSORPTION STUDY OF ACETONE ON THE SORBENTS BASED ON MONTMORILLONITE

Corresponding cation forms of the montmorillonite samples taken from the Ag-Dere bentonite deposit were obtained by processing them with Co2+ and Ni2+ salts. The nature and amount of acid sites formed on the surfaces of the obtained samples were studied by adsorption of acetone using the derivatographic method. The critical diameter of the acetone molecule is d = 5.6A0 and pkα = -7.2. Analysis of derivatograms shows that the mass loss changes depending on the ionic radius, nature and temperature of the cation exchanges as follows: Co2+ mont> Ni2+ mont> natural mont. Based on the conducted study it was estableshed that there are weak, medium and strong electron-acceptor centers on the surface of the sorbent which differ energetically. The endothermic effect observed on the DTA curve at a temperature range of 219.3–566.30C characterizes the physical adsorption of an acetone molecule on the surface of a montmorillonite sample. The effects observed at 706.9 and 775.70C characterize the strong acid sites. The amount of electron-acceptor centers formed on the surface of monmorillonite changes depending on the charge of cation exchangers. The number of electron-acceptor centers formed on the surface of Co2+ bentonite is higher than in other samples. The amount (a.mmol.g) and desorption energy (E, kDc, mol-1) of acetone molecule desorbed from the active sites in different temperature ranges were calculated. It was determined that the most capable of adsorbing acetone molecules is Co2+-montimorillonite, which can be used as a sorbent to prevent envoiremental pollution with acetone. Corresponding cation forms of the montmorillonite samples taken from the Ag-Dere bentonite deposit were prepared by processing with Co2+ and Ni2+ salts. The nature and amount of acid sites formed on the surfaces of the obtained samples were studied by adsorption of acetone using the derivatographic method. Based on the conducted study it was estableshed that there are weak, medium, strong electron-acceptor centers on the surface of the sorbent which differ energetically. The amount (a.mmol.\g) and desorption energy (E, kDc, mol-1) of acetone molecule desorbed from the active sites in different temperature ranges were calculated. As a result of the research, it was found that the most capable of adsorbing acetone molecules is Co2+-form of montimorillonite, which can be used as a sorbent to prevent envoiremental pollution with acetone

High-current-density Rutherford MgB2 cable sheathed by CuNi30 alloy

A Rutherford-type MgB2 cable has been fabricated from 12 six-core strands prepared by an internal magnesium diffusion (IMD) process with a resistive CuNi30 outer sheath. The uniformity of individual strands of diameter 0.448 mm prior to and after additional densification by rolling was studied by x-ray micro-tomography. The engineering current densities of the cable samples were measured at 4.2 K and external magnetic fields between 4.0 T and 8.0 T and compared with available published data. The presented Rutherford cable has the highest engineering current density with J e = 104 A cm2 measured in an external magnetic field of 5.73 T. The bending tolerance of the cable shows a critical diameter of 60 mm and less gradual critical current degradation in comparison to similar cables fabricated from single-core strands. The AC loss measurements of the present cable show lower coupling losses in comparison to monolithic multicore IMD conductors. The obtained results are promising for high-current-density and low-AC-loss MgB2 superconducting cables that are suitable especially for motors and generators.

Numerical study of sporadic combustion waves in straight channels of different diameters

The dynamics of flames propagating in straight channels filled with a stationary low-Lewis-number premixed gas mixture is studied numerically. A method for determining the propagation velocity of a sporadic combustion wave consisted of separate flame spots is proposed. Dependencies of the sporadic combustion wave propagation velocity, the residual fuel concentration and the number of flame spots on the channel size and the value of radiation heat losses are obtained. Analysis of numerical results show that for the channels of diameter exceeding some value the number of separate cup-like fragments constituting sporadic combustion wave is proportional to the channel cross-sectional area. At smaller diameters, the number of flame spots changes insignificantly and is one or two. It is shown that one of the universal characteristics of the sporadic combustion wave depending only on mixture properties but independent on system geometry is the area necessary to accommodate one reacting spot. Flame velocity which is another fundamental combustion characteristic is found to be almost independent on channel size starting from some critical diameter. This diameter, however, depends on mixture properties or radiative heat loss intensity and corresponds to the sporadic flame containing from several to ten reacting spots. Thus, the main properties of sporadic combustion waves in wide channels can be determined by numerical modeling of the flame propagation in the relatively narrow channels in which the flame consists of 1–10 cup-like fragments.

Virtual impaction in compressible flows with pressure recovery

Virtual impactors have been utilized towards classifying and increasing aerosol concentrations in sampling and measurement systems for half a century; in an ideal virtual impactor, sampled particles larger than a critical diameter (known as the cutsize) are directed inertially into a small fraction of the sample flow, known as the minor flow. Concentrating submicrometer particles with virtual impactors while maintaining near-atmospheric pressure downstream in the minor flow remains a challenge, due the low mass-to-drag ratios of these particles. Increased inertial behavior for small mass-to-drag ratio particles can be overcome by increasing flow velocities; however, in most prior work with virtual impaction of submicrometer particles, pressure recovery (keeping the aerosol outlet pressure similar to the inlet pressure) in the receiving tube at high sample flow rates was not investigated. Here, we describe the development and testing of virtual impactors functioning with flow velocities near the sonic limit, capable of submicrometer particle concentration, and with near-complete pressure recovery in the minor flow. We specifically designed, built, and tested two round-nozzle virtual impactors (denoted as VI-1 and VI-2) and evaluated their performances using fluorescent polystyrene latex particles and uranine-doped oleic acid particles with varying particle diameter. The results show that both virtual impactors, operating with 12 L per minute sample flow and a 10:1 sample flow-to-minor flow ratio, have submicrometer cutsizes (∼700 nm and 200 nm for VI-1 and VI-2, respectively) and near-complete pressure recovery. However, significant particle losses were observed in VI-2 with larger particle diameters. To understand such losses and particle trajectories in compressible flow virtual impactors, we also carried out computational fluid dynamics (CFD) simulations coupled with particle trajectory simulations. Importantly, trajectory calculations incorporated a recently developed drag model capable of predicting particle drag coefficients in a wide Mach number and Knudsen number (and hence Reynolds number) range. Trajectory calculations yielded cutsizes and large particle penetration curves in good agreement with experiments, indicating that large particle losses are due to overfocusing (radial inertial motion leading to deposition) within the nozzle and major flow chamber. Overfocusing always leads to an upper size limit in any virtual impactor system, but it is of greater concern in higher velocity systems. In addition to comparing simulations to measurements sampling at atmospheric pressure, we used trajectory calculations to examine compressible flow virtual impactor performance with variable sampling flow pressure and varying the driving pressure in the major flow. Such simulations reveal that sub-atmospheric pressure sampling leads to a reduced penetration “window” for virtual impaction, such that although it is possible for virtual impactor operation in reduced pressure environments, virtual impactors are applicable to a decreasing range of sizes at low pressure.

A radiomics-based study for differentiating parasellar cavernous hemangiomas from meningiomas

To investigate the value of the radiomic models for differentiating parasellar cavernous hemangiomas from meningiomas and to compare the classification performance with different MR sequences and classifiers. A total of 96 patients with parasellar tumors (40 cavernous hemangiomas and 56 meningiomas) were enrolled in this retrospective multiple-center study. Univariate and multivariate analyses were performed to identify the clinical factors and semantic features of MRI scans. Radiomics features were extracted from five MRI sequences using radiomics software. Three feature selection methods and six classifiers were evaluated in the training cohort to construct favorable radiomic machine-learning classifiers. The performance of different classifiers was evaluated using the AUC and compared to neuroradiologists. The detection rates of T1WI, T2WI, and CE-T1WI for parasellar cavernous hemangiomas and meningiomas were approximately 100%. In contrast, the ADC maps had the detection rate of 18/22 and 19/25, respectively, (AUC, 0.881) with 2.25 cm as the critical value diameter. Radiomics models with the SVM and KNN classifiers based on T2WI and ADC maps had favorable predictive performances (AUC > 0.90 and F-score value > 0.80). These models outperformed MRI model (AUC 0.805) and neuroradiologists (AUC, 0.756 and 0.545, respectively). Radiomic models based on T2WI and ADC and combined with SVM and KNN classifiers have the potential to be a viable method for differentiating parasellar hemangiomas from meningiomas. T2WI is more universally applicable than ADC values due to its higher detection rate for parasellar tumors.

Quantitative effects of pre-deformation prior to non-isothermal aging on the mechanical properties-microstructure relationships in an Al-3.51Cu-1.01Li alloy

The effects of increasing levels of pre-deformation on the mechanical properties and microstructure evolution (dominantly T1 phase) of an extensively used aerospace Al-Cu-Li alloy have been systematically investigated during the non-isothermal aging. Quantitative descriptions extracted from the microstructure parameters further revealed the separated strengthening contributions and mechanism. Pre-deformation prior to the NIA significantly accelerated the aging kinetics and improved the strength, and yet showed a limited benefit due to the generally decreased precipitation strengthening. Elevated pre-deformation in conjunction with the NIA process reduced the T1 diameter and interprecipitate spacing, the interprecipitate diffusion was gradually activated, responsible for the undulatory mean thickness. The experimental yield strength was successfully described by invoking the shearing mechanism in the pre-deformed samples (4–20 %). However, the strengthening transition from shearing to by-passing occurred in the 0 % sample, the by-passing model should be considered simultaneously owing to the larger diameter T1 precipitates. The critical diameter of the T1 precipitate for this transition ranged from 84 to 117 nm and was approximately 100 nm.

Tomographic study of the structure of cast and pressed trotyl charges

The sensitivity of condensed explosives depends strongly on the charge structure. Trotyl (TNT) is a typical example of such dependence. The pressed charges are more sensitive than the cast ones, which was confirmed in many studies including critical diameter tests and chemical spike width estimates. Our measurements of the electrical conductivity distributions in the dense TNT support the same conclusion.In this paper, results of tomographic study of the structure of pressed and cast trotyl are presented. The distribution functions of pores larger than 4 μm were obtained using synchrotron X-raying. In cast TNT, voids varying from units to hundred microns were observed, while the pressed charge was found to be substantially more uniform and less porous. The roles of possible mechanisms of hot spots generation are discussed.

Application of critical path analysis to streaming potential coupling coefficient in porous media

Streaming potential is a passive hydrogeophysical method that can be used to monitor water flow in porous media. However, a quantitative use of this method requires a good understanding of the streaming potential generation in water saturated porous media. In this work, we used the Critical Path Analysis (CPA) method to propose a new model to estimate the streaming potential coupling coefficient (SPCC) in porous media. By comparing the proposed model with 109 experimental data points for both unconsolidated samples such as uniform glass bead and sand packs and consolidated samples such as sandstones, carbonates and with 36 simulated data points, we demonstrated that the CPA is applicable to model the SPCC for porous media with both narrow and broad pore size distributions. Additionally, from the obtained result for the uniform grain packings, we found the rc–d relationship between the critical pore radius rc and grain diameter d that was validated by using 70 experimental data points available in literature. The obtained rc–d relationship may be helpful for applications of CPA-based models for uniform grain packings. We believe that the CPA-based model is an useful alternative approach for modeling the streaming potential coupling coefficient in porous media along with two other models available in literature.

A comparative study of micro-CT and mercury intrusion techniques for predicting permeability and surface area evolution during chemical dissolution

In this paper, we report on experimental and computational studies investigating the evolution of pore structure and permeability of a microporous carbonate rock during chemical dissolution using information provided from X-ray micro-computed tomography (µ-CT) and mercury intrusion porosimetry (MIP) techniques. We consider a chemical dissolution in a core sample by a nonacidic solution wherein a quasi-uniform modification of pore structure occurred. First, we conduct a comparative analysis on the capabilities and limitations of the µ-CT and MIP methods to quantify the evolution of pore size and pore surface area. In particular, we incorporate micropores into the calculations of the pore size-related parameters to highlight the uncertainties that ignoring microporosity causes. In the second part of the paper, we present predictive results on the fractional changes in the permeability of the rock using the Katz-Thompson (KT) and Kozeny-Carman (KC) models. The predictions are based on two characteristic parameters of the pore phase, i.e., the critical pore diameter and the specific pore surface area, and two characteristic macro-scale properties, i.e., porosity and formation factor, all calculated from both the MIP and µ-CT methods. The predicted changes in permeability are compared with those calculated directly on the images using the lattice-Boltzmann (LB) flow simulation on segmented images. The effect of changes in microporosity is also assessed to investigate its role in permeability evolution. The results showed that the KT model could reasonably predict the fractional changes in permeability in terms of the pore structure and macroscale parameters calculated from the MIP and µ-CT methods.

Influence of Copper and Zinc Tailing Powder on the Hydration of Composite Cementitious Materials.

Copper and zinc tailing powder (CZTP) is finely ground waste after copper minerals and zinc minerals have been extracted from ores during beneficiation. CZTP has certain potential cementitious properties and can be used in composite cementitious materials. The pore size distribution and hydrate phase assemblage of the hardened samples are investigated using MIP and XRD. SEM is employed to examine the microstructure of the specimens. The chemically bonded water is used to measure the degree of hydration. CZTP lowers the hydration heat evolution rate and the total hydration heat. The hydration heat evolution rate reduces as the w/b ratio rises, whereas the total hydration heat of blended cement paste rises. CZTP diminishes the strength development of the Portland-CZTP system, and the strength decreases as the CZTP level increases. CZTP reduces the critical pore diameters of the Portland-CZTP system with w/b = 0.3 after curing for 3 d and 28 d, while increasing the critical pore diameters of samples with w/b = 0.45 at the same age. CZTP increases the gel micropores of Portland-CZTP. Although CZTP increases the pore volume content of blended cement pastes with w/b = 0.3, the volume of harmful pores decreases. The pore volume content of the Portland-CZTP system decreases as the w/b ratio increases. However, the volume of harmful pores increases with a higher w/b ratio. The main hydration products in the Portland-CZTP system are portlandite, ettringite, and C-S-H. CZTP mainly played the role of filling or acting as a microaggregate in the Portland-CZTP system.

OSCILLATING BUBBLES RISING IN A DOUBLY CONFINED CELL

The motion of bubbles rising in confined geometries has gained interest due to its applications in mixing and mass transfer processes, ranging from bubble column reactors in the chemical industry to solar photobioreactors for algae cultivation. In this work we performed an experimental investigation of the behavior of air bubbles freely rising at high Reynolds numbers in a planar thin-gap cell of thicknessh=2.8 mm filled with distilled water. The in-plane width of the cell W is varied from 2.4 cm to 21 cm. We focus on the influence of lateral confinement on the motion of bubbles in the regimes with regular path and shape oscillations of large amplitude, that occur for the size range 0.6 cm<d<1.2cm. In addition, a rise regime that consists of a vertical rise path with regular shape oscillations, that does not appear in the laterally unconfined case, is uncovered. In the presence of lateral walls, the mean rise velocity of the bubble Vb becomes lower than the velocity of a laterally unconfined bubble of the same size beyond a critical bubble diameterdcVthat decreases as the confinement increases(i.e. as W decreases). The influence of the lateral confinement on the bubble mean shape can be determined from the change in the mean aspect ratio χ of the ellipse that best fits the bubble contour at each instant. It is observed that bubbles become closer to circular (χcloser to 1) as the confinement increases. The departure from the values of χ of the laterally unconfined case occur at a critical diameter dcχ that is lower for greater confinement and also greater than dcV for each confinement, thus indicating that the effect of the lateral confinement is seen earlier (i.e. on smaller bubbles) on the velocity than on the aspect ratio. Assuming that the wall effect is related to the strength of the downward flow generated by the bubble, we introduce the mean flow velocity in the space let free for the liquid between the walls and the bubble, Uf, that can be estimated by mass conservation as Uf=dVb/(W−d). We further introduce the relative velocity between the bubble and the downward fluid in its vicinity Urel=Vb+Uf=Vb/ξ, whereξ=1−d/Wis the confinement ratio of the bubble. We found that, for a given bubble size in the oscillatory regime, Urel is approximately constant for all the studied values of W, and matches closely the value in the absence of lateral confinement. This provides an estimation, at leading order, of the bubble velocity that generalizes the expression proposed by Filella et al. (JFM, 2015) and accounts for the additional drag experienced by the bubble due to the lateral walls. We then show that, for givendandξ, the frequency and amplitudes of the oscillatory motion can be predicted using the characteristic length and velocity scalesdandUrel.

Analysis of the magnetization for Fe and Ni ferromagnetic nanoparticles with variable geometry using VAMPIRE software

The purpose of this research is to have a quantitative analysis on the temperature dependence magnetization of ferromagnetic nanoparticles (NPs), i.e., the Curie temperature (Tc), was systematically studied. The atomistic simulations were carried out using the VAMPIRE 5.0 software based on the Landau-Lifshitz-Gilbert-Heun method. The variable parameters of the simulations were damping, time step, particle geometry (spherical, cubic, and cylindrical) and particle size. We have calculated λ for Fe and Ni, in addition we have found different Tc values for each nanogeometry studied following a finite-size effect. We have found ν values for cubic NPs close to the reported values. In particular, it was observed that the Tc values for the studied geometries in the case of Fe and Ni decreases from their theoretical bulk values, for a critical particle size diameter less than 5 nm. Hence, the presented results (optimized atomistic parameters such as simulation time step, damping, and critical exponents) are the basis for advanced simulations of hybrid and complex nanostructures with perspective in biomedical and environmental applications.

On the processes causing the alteration of cement-based materials while drying: Differential scanning calorimetry as a reliable tool for indirect microstructural analysis

Selecting the proper drying method is one of the critical choices that must be made before conducting experimental research on cement-based materials. Rapid drying might generate additional stress in the solid matrix, leading to the alteration of the pore structure. The size and connectivity of pores determine many physical properties such as permeability, gas diffusivity, heat conductivity, etc. Different techniques of drying have been analysed in the paper: oven drying at 105 °C, 60 °C, 30 °C, vacuum drying, and the isopropanol solution exchange method. Differential scanning calorimetry was applied to investigate the microstructure of the material. Knowing the relationship between the growing ice content and temperature decrease allows one to conclude about the pore size distribution of the material. The biggest advantage of the method is that calorimetric tests might be performed on the untreated sample. The information obtained for the virgin sample serves as the reference for the experimental results received for the samples exposed to various drying procedures. Experimental measurements have been performed on cement pastes prepared with a CEM I with water-to-cement ratio of 0.4, 0.5 and 0.6. The internal pore structure has been additionally investigated by means of the mercury intrusion porosimetry. The samples dried using the solution exchange method are characterized by the highest gel porosity. The other methods, especially drying at high temperatures, induce the collapse of the gel porosity and higher threshold and critical pore diameter values.

Application of a tailorable carbon molecular sieve to evaluate concepts for the molecular dimensions of gases

Molecular sieves have attracted considerable interest for gas separation applications due to their ability to discriminate substances by their molecule's size. To predict if a molecular sieve is suitable for a specific separation problem an accurate measure of the molecular sizes is called for. Furthermore, a high precision in estimations for molecular dimensions is needed for the characterization of materials using molecular probes. In this work, different popular concepts to estimate the size of a gas molecule, specifically Breck's kinetic diameter, the critical diameter and molecular dimensions by Webster (MIN-1) are discussed. These concepts are evaluated using a tailorable carbon molecular sieve. It is concluded, that the widely used kinetic diameter has some drawbacks to determine the accessibility of pores. Finally, recommendations for alternatives from existing literature are presented.

Circum-Antarctic abundance and properties of CCN and INPs

Abstract. Aerosol particles acting as cloud condensation nuclei (CCN) or ice-nucleating particles (INPs) play a major role in the formation and glaciation of clouds. Thereby they exert a strong impact on the radiation budget of the Earth. Data on abundance and properties of both types of particles are sparse, especially for remote areas of the world, such as the Southern Ocean (SO). In this work, we present unique results from ship-borne aerosol-particle-related in situ measurements and filter sampling in the SO region, carried out during the Antarctic Circumnavigation Expedition (ACE) in the austral summer of 2016–2017. An overview of CCN and INP concentrations over the Southern Ocean is provided and, using additional quantities, insights regarding possible CCN and INP sources and origins are presented. CCN number concentrations spanned 2 orders of magnitude, e.g. for a supersaturation of 0.3 % values ranged roughly from 3 to 590 cm−3. CCN showed variable contributions of organic and inorganic material (inter-quartile range of hygroscopicity parameter κ from 0.2 to 0.9). No distinct size dependence of κ was apparent, indicating homogeneous composition across sizes (critical dry diameter on average between 30 and 110 nm). The contribution of sea spray aerosol (SSA) to the CCN number concentration was on average small. Ambient INP number concentrations were measured in the temperature range from −5 to −27 ∘C using an immersion freezing method. Concentrations spanned up to 3 orders of magnitude, e.g. at −16 ∘C from 0.2 to 100 m−3. Elevated values (above 10 m−3 at −16 ∘C) were measured when the research vessel was in the vicinity of land (excluding Antarctica), with lower and more constant concentrations when at sea. This, along with results of backward-trajectory analyses, hints towards terrestrial and/or coastal INP sources being dominant close to ice-free (non-Antarctic) land. In pristine marine areas INPs may originate from both oceanic sources and/or long-range transport. Sampled aerosol particles (PM10) were analysed for sodium and methanesulfonic acid (MSA). Resulting mass concentrations were used as tracers for primary marine and secondary aerosol particles, respectively. Sodium, with an average mass concentration around 2.8 µg m−3, was found to dominate the sampled, identified particle mass. MSA was highly variable over the SO, with mass concentrations up to 0.5 µg m−3 near the sea ice edge. A correlation analysis yielded strong correlations between sodium mass concentration and particle number concentration in the coarse mode, unsurprisingly indicating a significant contribution of SSA to that mode. CCN number concentration was highly correlated with the number concentration of Aitken and accumulation mode particles. This, together with a lack of correlation between sodium mass and Aitken and accumulation mode number concentrations, underlines the important contribution of non-SSA, probably secondarily formed particles, to the CCN population. INP number concentrations did not significantly correlate with any other measured aerosol physico-chemical parameter.

Topology optimization based deterministic lateral displacement array design for cell separation

Circulating tumor cell (CTC) can be used to guide cancer theranostics. How to isolate efficiently CTCs from blood owns great clinical requirement. Deterministic lateral displacement (DLD) is a pillar-array-based effective passive microfluidic method to separate cells based on their sizes. DLD is a potential CTC isolation tool. Pillar shape is one of the key priorities in DLD array design. Altered zigzag mode is a normally undesired phenomenon that leads zigzag particles away from flow direction. This work makes use of the altered zigzag mode to manipulate zigzag particles for the first time, and developed a novel DLD chip with topology optimized pillar shape and a wide DLD channel. The novel designing method based on topology optimization (TO) greatly increases lateral displacement of different sized cells, meanwhile demonstrates its universality and expansibility. The proposed structure has the ability to shorten the device and to manipulate cells flexibly. Bead experiment has been applied to determine the critical diameter of the DLD array. Numerical, bead and cell experiment have been carried out to verify the separation efficiency of the structure. The TO-based wide DLD channel promotes the separation efficiency.

New criteria for predicting compositions with high glass-forming ability in Zr–Co–Al alloys

We show that the widespread parameters PHS, PHSS and δ related with mixing enthalpy, mismatch entropy, configurational entropy and atom size difference do not provide proper prediction of the bulk metal glasses (BMGs) compositions with high glass-forming ability in Zr-Co-Al system. A new computational approach has been developed for the accurate determination of BMGs compositions having a maximum critical diameter (Dmax). Using new parameters ΘCo-Zr(xCo), ΘAl-Zr(xAl), the range of Co-Zr-Al compositions with the best GFA was determined and Zr55Co29Al16 composition with maximum Dmax was identified. The thermodynamic mixing functions (∆Gmix, ∆Hmix) for the glass-forming Zr-Co-Al system were calculated for the first time. The results obtained reveal a relationship between thermodynamic and geometric factors and open up prospects for the development of reliable theoretical methods for new metallic glasses discovery.

Modeling Results for the Real Horizontal Heavy-Oil-Production Well of Mechanical Solids

Recently, more and more new oil fields entering commercial production are complicated by the content of high-viscosity products, which are located at relatively shallow depths. For the rational development of such fields, a network of horizontal wells is used. A special feature of these objects is a weakly cemented reservoir, which leads to significant sand occurrence during well operation. At the same time, the removal of mechanical impurities cannot be avoided even when using complex measures, including the use of various filters. There are quite a few methods describing the behavior of mechanical impurities in gas–liquid flows. The purpose of the work was to analyze the removal of mechanical impurity particles from horizontal wells with high-viscosity oil. A model of a typical well in the OLGA software was created, and data on the types of particle removal were obtained. As a result of calculations, the quality of removal for different diameters of mechanical impurities was determined, and the dependence of the critical diameter on the well flow rate was constructed.