Collision Mode Research Articles

Numerical analysis of deposition frequency for successive droplets coalescence dynamics

A pseudopotential based multi-relaxation-time lattice Boltzmann model is employed to investigate the dynamic behaviors of successive droplets’ impact and coalescence on a solid surface. The effects of deposition frequency on the morphology of the formed line are investigated with a zero receding contact angle by analyzing the droplet-to-droplet coalescence dynamics. Two collision modes (in-phase mode and out-of-phase mode) between the pre-deposited bead and the subsequent droplet are identified depending on the deposition frequency. A uniform line can be obtained at the optimal droplet spacing in the in-phase mode (Δt* < 1.875). However, a scalloped line pattern is formed in the out-of-phase mode (Δt* > 1.875). It is found that decreasing the droplet spacing or advancing contact angle can improve the smoothness of line in the out-of-phase mode. Furthermore, the effects of deposition frequency on the morphology of the formed lines are validated to be applicable to cases with a finite receding contact angle.

Determination of toxic and essential trace elements in serum of healthy and hypothyroid respondents by ICP-MS: A chemometric approach for discrimination of hypothyroidism

Inductively coupled plasma-mass spectrometry ((ICP-MS)) was used to determine three toxic (Ni, As, Cd) and six essential trace elements (Cr, Mn, Co, Cu, Zn, Se) in blood serum of patients with hypothyroidism (Hy group) and healthy people (control group), in order to set the experimental conditions for accurate determination of a unique profile of these elements in hypothyroidism. Method validation was performed with standard reference material of the serum by varying the sample treatment with both standard and collision mode for analysis of elements isotopes. Quadratic curvilinear functions with good performances of models and the lowest detection limits were obtained for 52Cr, 66Zn, 75As, 112Cd in collision mode, and 55Mn, 59Co, 60Ni, 65Cu, 78Se in standard mode. Treatment of serum samples with aqueous solution containing nitric acid, Triton X-100 and n-butanol gave the best results. Chemometric tools were applied for discrimination of patients with hypothyroidism. All nine elements discriminated Hy group of samples with almost the same discriminating power as indicated by their higher values for this group of patients. Statistically significant correlation (p < 0.01) was observed for several elements. Results indicated clear differences in element profile between Hy and control group and it could be used as a unique profile of hypothyroid state.

Lattice Boltzmann study of successive droplets impingement on the non-ideal recessed microchannel for high-resolution features

Successive droplets deposited high-resolution features on the non-ideal recessed microchannel is investigated utilizing a 3D multiple-relaxation-time (MRT) pseudopotential lattice Boltzmann (LB) model with large density ratios and high Reynolds numbers. The non-ideal hydrophilic wettability is modeled by the geometric formulation within the pseudopotential LB framework. Firstly, for single droplet impingement on the square microchannel, three liquid morphologies including quatrefoil-like, quasi-square and quasi-rounded footprints are observed with varying aspect ratios of microchannel. Next, considering two successive droplets impingement on the rectangular microchannel, with the droplet spacings increasing, the liquid morphologies including bulging, uniform and dumbbell footprints are quantitatively identified. With the formation of connecting ridge, the optimal droplet spacing in in-phase collision mode is larger than that in out-of-phase mode. Besides, the deviations between simulations and theoretical values are observed which are attributed to the intensive inertial dominated flows. Finally, as extending to the multi-droplets deposited lines and films, the optimal droplet spacings are adaptive in both collision and placement modes for uniform and high-resolution features.

Influence of restraint system activation timing on occupant injury in various collision modes

Influence of restraint system activation timing on occupant injury in various collision modes

Risk Indicators and Road Accident Analysis for the Period 2012–2016

Road accidents are a major societal issue for every country. The purpose of this paper is to assess the number of traffic and road accidents depending on a series of variables (collision mode, road configuration, conditions of occurrence, road category, type of vehicle involved, personal factors, and length of time of the driving license) in Romania from 2012–2016. The analysis of the road accident trend identifies the causes of accidents, road safety performance indicators, and risk indicators. Having these identified data, a framework is proposed for improving the road safety system and reducing accidents. The Romanian Police, the National Institute of Statistics (NIS) in Romania, and the European Commission provided the data used for this analysis. The data obtained from these databases are analysed and evaluated according to a series of variables. This paper will outline an informative image of road accidents and establish a framework for reducing their effects in road transport. As a result of the analysis, we have seen that the combination of vehicles and personal factors influences the number of traffic and road accidents.

Numerical studies of freight railcar

In this paper static strength analysis of body and frame of the covered railcar model 11-9962 with the weight of 0.922 MN is carried out. Numerical study of freight railcar is carried out by the finite element method. Calculation model consists of plates and beams linked together at the nodal points simulating the elements of the railcar body. The main objective of the static strength analysis was to evaluate strength and bearing capacity of railcar structure and to evaluate the conformity of freight railcar structure to regulatory requirements. Typical for the static loading mode is a single and continuous application of an external load, gradually increasing from zero to the maximum value.The calculation scheme of railcar takes into account forces acting on it in operating conditions. Load modes considered are: I, III basic modes, collision and jerk mode, repair modes (when jacking up a railcar by jacks), railcar loading mode (on possibility of using electric and autoloader for loading), roof strength test. From the analysis results it follows that stresses in all body elements and frame of the covered railcar model 11-9962, for all design modes, do not exceed the permissible values, and railcar structure conforms to the current regulations. Analysis showed good agreement with the test results for strength of the prototype railcar.

Chirally sensitive collision induced dissociation of proton-bound diastereomeric complexes of tryptophan and 2-butanol.

In this work we report the stereo-dependent collision-induced dissociation (CID) of proton-bound complexes of tryptophan and 2-butanol. The dissociation efficiency was measured as a function of collision energy in single collision mode. The homochiral complex was found to be less stable against CID than a heterochiral one. Additional gas dependence measurements were performed with diastereomeric complexes that confirm the findings.

A differential approach for modeling revolute clearance joints in planar rigid multibody systems

A non-penetration approach of frictional contact analysis is presented for modeling revolute clearance joints of planar rigid multibody systems. In the revolute clearance joint, the motion modes of the journal are divided into three categories, namely, the free motion, collision, and permanent contact modes. The switch between different contact modes is identified by the state of the journal and bearing, including the gap and the normal relative velocity. When impact in the revolute clearance joint is detected, the collision process is simulated by the impulse-based differential approach, where Stronge’s improved model for restitution is employed to determine the relative velocity after impact. Instead of algebraic equations, the impact process is described by a set of ordinary differential equations (ODEs), which avoids solving complementarity problems. Moreover, in the permanent contact mode, the constraint-based approach and modified Coulomb’s friction law are adopted. The permanent contact mode maintains for most of the time and the governing ODEs are non-stiff. There is general agreement that the constraint-based approach is more efficient than the force-based method. A slider–crank mechanism with a revolute clearance joint is considered as a demonstrative application example where the comparison with the continuous contact force model is investigated.

Purity of MoO3 from different manufacturers

Inductively coupled plasma mass spectrometry with the use of a reaction cell in collision mode has been used to determine the concentrations of 68 elemental impurities in six commercially available molybdenum( VI) oxide reagents. The results indicate that the purity of the reagents is not better than 3N (99.9 wt %). A major impurity in the MoO3 samples is tungsten. Its concentration ranges from 5 × 10–3 to 6 × 10–2 wt %, depending on the manufacturer.

The performance of single and multi-collector ICP-MS instruments for fast and reliable 34S/32S isotope ratio measurements.

The performance and validation characteristics of different single collector inductively coupled plasma mass spectrometers based on different technical principles (ICP-SFMS, ICP-QMS in reaction and collision modes, and ICP-MS/MS) were evaluated in comparison to the performance of MC ICP-MS for fast and reliable S isotope ratio measurements. The validation included the determination of LOD, BEC, measurement repeatability, within-lab reproducibility and deviation from certified values as well as a study on instrumental isotopic fractionation (IIF) and the calculation of the combined standard measurement uncertainty. Different approaches of correction for IIF applying external intra-elemental IIF correction (aka standard-sample bracketing) using certified S reference materials and internal inter-elemental IIF (aka internal standardization) correction using Si isotope ratios in MC ICP-MS are explained and compared. The resulting combined standard uncertainties of examined ICP-QMS systems were not better than 0.3–0.5% (uc,rel), which is in general insufficient to differentiate natural S isotope variations. Although the performance of the single collector ICP-SFMS is better (single measurement uc,rel = 0.08%), the measurement reproducibility (>0.2%) is the major limit of this system and leaves room for improvement. MC ICP-MS operated in the edge mass resolution mode, applying bracketing for correction of IIF, provided isotope ratio values with the highest quality (relative combined measurement uncertainty: 0.02%; deviation from the certified value: <0.002%).

Single molecular catalysis of a redox enzyme on nanoelectrodes.

Due to a high turnover coefficient, redox enzymes can serve as current amplifiers which make it possible to explore their catalytic mechanism by electrochemistry at the level of single molecules. On modified nanoelectrodes, the voltammetric behavior of a horseradish peroxidase (HRP) catalyzed hydroperoxide reduction no longer presents a continuous current response, but a staircase current response. Furthermore, single catalytic incidents were captured through a collision mode at a constant potential, from which the turnover number of HRP can be figured out statistically. In addition, the catalytic behavior is dynamic which may be caused by the orientation status of HRP on the surface of the electrode. This modified nanoelectrode methodology provides an electrochemical approach to investigate the single-molecule catalysis of redox enzymes.

Distinguishing isomeric aldohexose-ketohexose disaccharides by electrospray ionization mass spectrometry in positive mode.

The identification of the structure of carbohydrates is challenging because of their complex composition of monosaccharide units, linkage position and anomeric configuration. We used a combination of principle component analysis (PCA) and tandem mass spectrometry (MS/MS), including collision-induced dissociation (CID) and higher energy collision dissociation (HCD), to distinguish four aldohexose-ketohexose isomers, sucrose, turanose, maltulose, and palatinose, which are composed of glucose and fructose. The electrospray ionization (ESI)-MS/MS spectra of the lithium and sodium adducts of the glucopyranosyl fructose (Glc-Fru) isomers were recorded on two independent mass spectrometers using CID (MicroTOF QII) and HCD (Q-Exactive Orbitrap). The differences between the fragment ions were evaluated by the PCA models. The glycosidic bond cleavage mechanism of lithiated sucrose was verified by a deuterium-labeling experiment combined with density functional theory calculations (Gaussian 09). The main fragment ions in the MS/MS spectra from the glycosidic bond decomposition, cross-ring cleavage (-90 Da), and dehydration of the precursor ions of m/z 349 ([M+Li](+)) and m/z 365 ([M+Na](+)) were observed. Surprisingly, cross-ring cleavage and dehydration of the precursor ions were rarely observed in both lithiated and sodiated sucrose. There were significant differences in the fragmentation patterns and relative abundances of fragment ions in second-order mass spectrometry, which allowed discriminant models to be constructed for the alkali adducts and collision modes. Glc-Fru isomers were discriminated in the PCA score plots for their lithium and sodium adducts by using different collision modes. The results showed that HCD-MS/MS is an ideal tool for differentiating lithium adducts, whereas, CID-MS/MS is better for discriminating sodium adducts. The hydrogen migration of the hydroxyl group at C3 of the fructose unit caused the glycosidic bond decomposition of lithiated sucrose.

Numerical simulation of flow characteristics for non-spherical particle mixture flowing in moving bed

Environmental pollution problems are more serious with the rapid economic development. The study of particle flow characteristics is a hot issue for scholars. In many ways to tackle air pollution and solid waste, the particle flow characteristics can play a decisive role. Then in the actual process, the non-spherical particle such as active carbon and solid waste were always treated as spherical particles during the simulation. It could cause large errors. This study was mainly to simulate the non-spherical particles. Three kinds of non-spherical particles including corn-shaped particle, cylinder paritcle and ellipsoidal particle were developed by multi-element particle model. The motion equation for non-spherical particle mixture was founded based the analysis on the collision mechanism and the typical collision mode. The flowing condition of non-spherical particle mixture in moving bed was simulated through experiment, which verified the the reliability of multi-element particle model. The discharge rate, flow pattern, particle density distribution and voidage variation for non-spherical particle mixture were discussed further. The results showed that the discharge rate for non-spherical particle mixture was fundamentally the same as single non-spherical particle. However, the value for spherical particle was larger than that of spherical and non-spherical particle mixture. The MFI values (the particle speed ratio of bedside to centre in moving bed) of nonspherical particles mixture were closer to the corresponding homogeneous particles. The particle density distribution of spherical and spherical-nonspherical mixture generally had one peak, while that of non-spherical particle and non-spherical particle mixture always had two peaks. The wall effect and the average voidage of three kinds of non-sphercial particle mixture were almost the same. The average voidage of three kinds of non-sphercial particle mixture are almost the same.

Majorana neutrinos production at LHeC in an effective approach

We investigate the possibility of detecting Majorana neutrinos at the Large Hadron-electron Collider (LHeC), an electron-proton collision mode at CERN. We study the $l_j^{+} + 3 jets$ ($l_j\equiv e ,\mu ,\tau$) final states which are, due to leptonic number violation, a clear signature for intermediate Majorana neutrino contributions. Such signals are not possible if the heavy neutrinos have Dirac nature. The interactions between Majorana neutrinos and the Standard Model (SM) particles are obtained from an effective lagrangian approach. We present our results for the total cross section as a function of the neutrino mass, the effective couplings and the new physics scale. We also show the discovery region as a function of the Majorana neutrino mass and the effective couplings. Our results show that the LHeC may be able to discover Majorana neutrinos with masses lower than $700$ GeV and $1300$ GeV for electron beams settings of $E_e=50$ GeV and $E_e=150$ GeV, respectively.

Analysis of radium-226 in high salinity wastewater from unconventional gas extraction by inductively coupled plasma-mass spectrometry.

Elevated concentration of naturally occurring radioactive material (NORM) in wastewater generated from Marcellus Shale gas extraction is of great concern due to potential environmental and public health impacts. Development of a rapid and robust method for analysis of Ra-226, which is the major NORM component in this water, is critical for the selection of appropriate management approaches to properly address regulatory and public concerns. Traditional methods for Ra-226 determination require long sample holding time or long detection time. A novel method combining Inductively Coupled Mass Spectrometry (ICP-MS) with solid-phase extraction (SPE) to separate and purify radium isotopes from the matrix elements in high salinity solutions is developed in this study. This method reduces analysis time while maintaining requisite precision and detection limit. Radium separation is accomplished using a combination of a strong-acid cation exchange resin to separate barium and radium from other ions in the solution and a strontium-specific resin to isolate radium from barium and obtain a sample suitable for analysis by ICP-MS. Method optimization achieved high radium recovery (101 ± 6% for standard mode and 97 ± 7% for collision mode) for synthetic Marcellus Shale wastewater (MSW) samples with total dissolved solids as high as 171,000 mg/L. Ra-226 concentration in actual MSW samples with TDS as high as 415,000 mg/L measured using ICP-MS matched very well with the results from gamma spectrometry. The Ra-226 analysis method developed in this study requires several hours for sample preparation and several minutes for analysis with the detection limit of 100 pCi/L with RSD of 45% (standard mode) and 67% (collision mode). The RSD decreased to below 15% when Ra-226 concentration increased over 500 pCi/L.

The Choice of Conditions for the Determination of Vanadium, Chromium and Arsenic Concentration in Waters by ICP-MS Using Collision Mode

Inductively coupled plasma mass spectrometry (ICP-MS) is a popular method for the analysis of waters with various matrices and salinity. One of the difficulties of routine measurements by ICP-MS is spectral interferences conditioned by polyatomic ion formation in the plasma. The detection of the background concentration of such elements as vanadium, chromium and arsenic in natural waters by ICP-MS is complicated because of the polyatomic interferences, having the same mass-to-charge ratio. Thus, the purpose of this article is to determine the optimal rate of helium flow for the effective correction of polyatomic interferences of vanadium, chromium and arsenic and the reduction of their detection limits in Cl-rich waters. This research has been carried out using an inductively coupled plasma mass spectrometer NexION 300D with a universal cell technology (UCT) (PerkinElmer, USA) and three model solutions. For the detection of vanadium, chromium and arsenic content in chloride matrix water by ICP-MS, a collision mode is preferable for polyatomic interference correction. The optimal helium flow rate for this purpose is 2.5ml/min. Under these conditions, the detection limit of vanadium, chromium and arsenic decreases by order of two.

Comparison of MP AES and ICP-MS for analysis of principal and selected trace elements in nitric acid digests of sunflower (Helianthus annuus)

The use of nitrogen as plasma gas for microwave plasma atomic emission spectroscopy (MP AES) is an interesting development in analytical science since the running cost can be significantly reduced in comparison to the inductively coupled argon plasma. Here, we evaluate the performance of the Agilent 4100 MP AES instrument for the analysis of principal metals (Ca, K, Mg, and Na), lithogenic metals (Al, Fe, and Mn) and selected trace metals (As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V, and Zn) in nitric acid plant digests. The digests were prepared by microwave-assisted dissolution of dry plant material from sunflower (Helianthus annuus) in concentrated nitric acid. Comparisons are made with analysis of the same solutions with ICP-MS (Agilent 7500cx) using the octopole reaction system (ORS) in the collision mode for As, Fe, and V.The limits of detection were usually in the low µgL−1 range and all principal and lithogenic metals were successfully determined with the MP AES and provided almost identical results with the ICP-MS. The same applies for the selected trace metals except for As, Co and Mo where the concentrations were below the detection limit with the MP AES. For successful analysis we recommend that (i) only atom lines are used, (ii) ionization is minimized (e.g. addition of CsNO3) and (iii) the use of internal standards should be considered to resolve spectral interferences.

Experimental study on propagation mode of H2/Air continuously rotating detonation wave

The propagation mode of H2/Air continuously rotating detonation waves (CRDWs) has been experimentally studied in a rotating detonation engine (RDE) model which injected gaseous H2 and Air in slit-orifice collision mode. Experiments were conducted by varying injection conditions (different mass flow rates and equivalence ratio) at atmospheric backpressure, and thereby four typical detonation propagation modes were concluded. Moreover, the injection conditions, as well as the time domain and frequency domain characteristics for each mode were detailedly analyzed. Results show that: for the test model with an oxidizer injection throat of 0.4 mm wide, H2/Air CRDW usually propagated in an one-way mode as the mass flow rate increased, which in sequence included three sorts of mode: single wave mode, single/dual-wave hybrid mode, and dual-wave mode. However, after the blow-off N2 was injected and the H2 flow began to decrease, the detonation was possible to be maintained in a special dual-wave collision mode. This collision mode was more likely to be observed in the test model with a narrower oxidizer injection throat of 0.2 mm wide. At lower mass flow rate, CRDWs tended to show unstable dual-wave collision mode, and the collision points slowly moved back and forth within a small azimuthal angle; with the mass flow rate increasing, the collision points remained stable and CRDWs propagated in stable dual-wave collision mode.

Coarse- and fine-grid numerical behavior of MRT/TRT lattice-Boltzmann schemes in regular and random sphere packings

We analyze the intrinsic impact of free-tunable combinations of the relaxation rates controlling viscosity-independent accuracy of the multiple-relaxation-times (MRT) lattice-Boltzmann models. Preserving all MRT degrees of freedom, we formulate the parametrization conditions which enable the MRT schemes to provide viscosity-independent truncation errors for steady state solutions, and support them with the second- and third-order accurate (“linear” and “parabolic”, respectively) boundary schemes. The parabolic schemes demonstrate the advanced accuracy with weak dependency on the relaxation rates, as confirmed by the simulations with the D3Q15 model in three regular arrays (SC, BCC, FCC) of touching spheres. Yet, the low-order, bounce-back boundary rule remains appealing for pore-scale simulations where the precise distance to the boundaries is undetermined. However, the effective accuracy of the bounce-back crucially depends on the free-tunable combinations of the relaxation rates. We find that the combinations of the kinematic viscosity rate with the available “ghost” antisymmetric collision mode rates mainly impact the accuracy of the bounce-back scheme. As the first step, we reduce them to the one combination (presented by so-called “magic” parameter Λ in the frame of the two-relaxation-times (TRT) model), and study its impact on the accuracy of the drag force/permeability computations with the D3Q19 velocity set in two different, dense, random packings of 8000 spheres each. We also run the simulations in the regular (BCC and FCC) packings of the same porosity for the broad range of the discretization resolutions, ranging from 5 to 750 lattice nodes per sphere diameter. A special attention is given to the discretization procedure resulting in significantly reduced scatter of the data obtained at low resolutions. The results reveal the identical Λ-dependency versus the discretization resolution in all four packings, regular and random. While very small Λ values overestimate the drag measurements several-fold on the coarse grids, Λ>1 may overestimate the permeability at the same extent. In low resolution region we provide practical guidelines, extending previously known solutions for the straight/diagonal Poiseuille flow. Analysis of the high-resolution region reveals the collapse of the solutions obtained with all the considered Λ values with the average rate of −1.3, followed by their common, smooth, first-order convergence with the rate of −1.0 as the best, towards the reference solutions provided by the “parabolic” schemes. High-quality power-law fits estimate that the bounce-back would reach their accuracy (obtained at about 200 nodes per sphere) for two-order magnitude higher grid resolution.

Heavy-ion physics studies for the Future Circular Collider

The Future Circular Collider (FCC) design study is aimed at assessing the physics potential and the technical feasibility of a new collider with centre-of-mass energies, in the hadron-hadron collision mode including proton and nucleus beams, more than seven-times larger than the nominal LHC energies. An electron-positron collider in the same tunnel is also considered as an intermediate step, which would provide the electron-hadron option in the long term. First ideas on the physics opportunities with heavy ions at the FCC are presented, covering the physics of Quark-Gluon Plasma, gluon saturation, photon-induced collisions, as well as connections with ultra-high-energy cosmic rays.