Two-dimensional Code Research Articles

Research on asphalt mixture force chain identification criteria based on computational granular mechanics

The difference in force chains can be used to evaluate asphalt mixture skeleton structure. In this study, different asphalt mixture discrete element method models were established via the two-dimensional particle flow code software to analyze force chain identification criteria. And then, the force chain lengths of different asphalt mixtures were quantified preliminarily. Results indicate that the average contact force [Formula: see text] needs to be set as the contact force threshold value. The recommended angle threshold value is 45°. For asphalt mixtures, less than 50% aggregate content is involved in transferring external loading. Whether the aggregate is located on the force chains should be regarded as an important criterion to judge whether the aggregate is involved in the asphalt mixture skeleton composition. Although dense-graded asphalt concrete will generate many force chains, most of them are short length force chains that are not conducive to transferring load.

Numerical Simulation of the Absorption of Laser Radiation in a Plasma Including the Resonance Mechanism and Generation of Fast Electrons for the Conditions of a Nuclear Fusion Target Ignition

A model of resonance absorption of laser radiation in a plasma involving the deformation of the density profile by the ponderomotive force has been proposed. A mechanism of the linear transformation of laser radiation into plasma waves at resonance absorption has been discussed. The quasilinear diffusion equation for the electron distribution function in the plasma field has been used to describe the generation of fast electrons by plasma waves. Formulas have been obtained to estimate the energy fraction absorbed through the resonance mechanism and the energy of fast electrons. These formulas have been used in the two-dimensional hydrodynamic code ATLANT-HE. The hydrodynamics of the plasma and the absorption of laser radiation have been calculated for conditions of the NIF facility experiment at a radiation power of 30 ТW and a base pulse duration of 7.5 ns. The plasma has the spatial dimensions appearing upon the irradiation of a spherical target for the initiation of the fusion reaction. The calculations have shown that the resonance absorption mechanism leads to the generation of fast electrons with an energy of about 40–80 keV. Fast electrons carry an energy of about 1–1.5% of the laser energy. These results are close to the experimental data.

Numerical simulation of rock mass blasting using particle flow code and particle expansion loading algorithm

Numerical simulation of limestone rock mass blasting was carried out using the two-dimensional particle flow code (PFC2D) within the discrete element modeling framework, and the explosion load was loaded using the particle expansion algorithm. A field experiment of rock blasting was also carried out from which the size of the blasting funnel and the maximum blasting vibration velocity were recorded. The simulation results were compared with the experimental results in two aspects: the blasting result and the post-explosion effect. From the comparison, it has been observed that the size of the blasting funnel obtained from the numerical simulation shows a good agreement with the field experiment. However, in the case of the post-explosion effect (the blasting vibration velocity), the results of the numerical simulation and the vibration velocity curve obtained from the field test show disagreement to a certain extent. This demonstrates that the particle expansion loading algorithm is reliable in simulating the rock blasting process. The results of this research serve as a reference for subsequent applications of the PFC method in the field of rock blasting.

Recent progress in the design of the K-DEMO divertor

Abstract The preliminary conceptual design of the Korean fusion demonstration reactor (K-DEMO) with a major radius of 6.8 m and the fusion power of 2200 MW has been studied since 2012. The overall configuration of the K-DEMO divetor system based on the ITER-like water-cooled tungsten technology is a double-null type symmetric divertor subdivided into 32 toroidal modules for the vertical maintenance. A detached divertor scenario with impurity seeding was considered as the primary approach for the power exhaust to reduce the peak heat flux lower than the engineering limit of 10 MW/m2. The power exhaust performance at the scrap off layer was estimated by using UEDGE-2D code, a two-dimensional fluid transport code for collisional edge plasma and neutral species like N, Ne, and Ar. Particle and heat flux on inboard and outboard divertor targets were calculated for the detached cased depending on parameters such as the impurity seeding rate, pumping rate, and the pedestal density. On the other hand, a magnetic solution like X-divertor, snowflake divertor, and super X-divertor to expand the plasma wet area was considered for K-DEMO since the detached divertor increasing a radiation fraction by impurity seeding might be able to be unstable. However, the extremely high current of poloidal coils was required more than the engineering limit, 20 MA, to form magnetic field lines for the alternative divertors. Based on the physical calculation of the edge plasma, engineering analyses were carried out to find out the thermal and structural reliability. The thermo-hydraulic analysis confirmed thermal stability, whether all comprising materials are operating within their allowable temperature windows when the case of the peak heat flux is set to 10 MW/m2 on the outboard divertor target. The response surface optimization method derived two optimal design candidates employing two kinds of heat sink materials, respectively: the reduced activation ferritic martensitic (RAFM) steel and CuCrZr alloy. The drawbacks and merits of the two materials were definite. The optimal design with applying RAFM steel was vulnerable to withstand thermal and mechanical loads since low thermal conductivity caused too thin thickness of the heat sink. On the other hand, the CuCrZr alloy has critical drawbacks in terms of activation and radioactive waste despite its high thermal conductivity. Meanwhile, preliminary electromagnetic (EM) analysis was carried out to estimate the EM loads caused by the abnormal behaviors of plasma since EM loads are one of the most critical external loads for designing a DEMO divertor.

Explicit Constructions of Two-Dimensional Reed-Solomon Codes in High Insertion and Deletion Noise Regime

Insertion and deletion (insdel for short) errors are synchronization errors in communication systems caused by the loss of positional information in the message. Reed-Solomon codes have gained a lot of interest due to its encoding simplicity, well structuredness and list-decoding capability in the classical setting. This interest also translates to the insdel metric setting, as the Guruswami-Sudan decoding algorithm can be utilized to provide a deletion correcting algorithm in the insdel metric. Nevertheless, there have been few studies on the insdel error-correcting capability of Reed-Solomon codes. Our main contributions in this article are explicit constructions of two families of 2-dimensional Reed-Solomon codes with insdel error-correcting capabilities asymptotically reaching those provided by the Singleton bound. The first construction gives a family of Reed-Solomon codes with insdel error-correcting capability asymptotic to its length. The second construction provides a family of Reed-Solomon codes with an exact insdel error-correcting capability up to its length. Both our constructions improve the previously known construction of 2-dimensional Reed-Solomon codes whose insdel error-correcting capability is only logarithmic on the code length.

DID Code: A Bridge Connecting the Materials Genome Engineering Database with Inheritable Integrated Intelligent Manufacturing

Abstract A data identifier (DID) is an essential tag or label in all kinds of databases—particularly those related to integrated computational materials engineering (ICME), inheritable integrated intelligent manufacturing (I3M), and the Industrial Internet of Things. With the guidance and quick acceleration of the development of advanced materials, as envisioned by official documents worldwide, more investigations are required to construct relative numerical standards for material informatics. This work proposes a universal DID format consisting of a set of build chains, which aligns with the classical form of identifier in both international and national standards, such as ISO/IEC 29168-1:2000, GB/T 27766–2011, GA/T 543.2–2011, GM/T 0006–2012, GJB 7365–2011, SL 325–2014, SL 607–2018, WS 363.2–2011, and QX/T 39–2005. Each build chain is made up of capital letters and numbers, with no symbols. Moreover, the total length of each build chain is not restricted, which follows the formation of the Universal Coded Character Set in the international standard of ISO/IEC 10646. Based on these rules, the proposed DID is flexible and convenient for extending and sharing in and between various cloud-based platforms. Accordingly, classical two-dimensional (2D) codes, including the Hanxin Code, Lots Perception Matrix (LP) Code, Quick Response (QR) code, Grid Matrix (GM) code, and Data Matrix (DM) Code, can be constructed and precisely recognized and/or decoded by either smart phones or specific machines. By utilizing these 2D codes as the fingerprints of a set of data linked with its cloud-based platforms, progress and updates in the composition–processing–structure–property–performance workflow process can be tracked spontaneously, paving a path to accelerate the discovery and manufacture of advanced materials and enhance research productivity, performance, and collaboration.

A three-dimensional PWR-core pin-by-pin analysis code NECP-Bamboo2.0

A PWR-core pin-by-pin fuel management calculation code system named NECP-Bamboo2.0 has been developed, including the two-dimensional lattice calculation code Bamboo-Lattice2.0 and the three-dimensional steady-state whole-core pin-by-pin calculation code Bamboo-Core2.0. Pin-cell homogenized few-group constants are handled in an optimized least-square fitting form. A tightly coupled calculation strategy is employed for multi-physics coupling iterative process. A three-dimensional whole-core spatial parallel algorithm based on the unified domain decomposition is established to decrease both computing time and storage. (1) Compared with the traditional two-step method, the pin-by-pin calculation can ensure the accuracy of reactor reactivity, can reduce the average error of pin-power calculation from 2% to 1% for large commercial PWR core, can reduce the error of pin-power from 11% to 3% for the small PWR core. (2) NECP-Bamboo2.0 can directly provide pin-resolved distributions, including coolant temperature, fuel temperature, burnup and so on. The corresponding accuracy is comparable with one-step high-fidelity results.

Numerical modeling of the fractured zones around a blasthole

The high-energy rate of shock waves, as an important part of explosion energy, plays a significant role in the mechanism of rock fragmentation. This energy rate and the mechanism of rock fracturing are controlled by several parameters related to both the explosive charge and rock mechanical properties. In this study, the mechanism of rock fragmentation due to blast-induced shock waves in a single blasthole was numerically simulated by a two-dimensional discrete element code. The numerical results included the stresses around the blastholes, the number of blast-induced fractures and the density of cracks, which were compared with the corresponding experimental results. This comparison showed that the numerical results were in good agreement with their experimental counterparts. It is concluded that the proposed numerical model could be effectively used for the simulation of the crack propagation process around a blasthole.

The Effect of Electron Donation and Intermolecular Interactions on Ultralong Phosphorescence Lifetime of 4-Carnoyl Phenylboronic Acids.

Purely organic phosphors with persistent room-temperature phosphorescence (RTP) demonstrate promising potential applications in optoelectronic area, bioimaging, and chemical sensing. However, it is still a formidable challenge to further design new organic phosphors due to the unclear mechanism to produce ultralong phosphorescence lifetimes. This paper investigates the correlation between the ultralong phosphorescence lifetime and structure of a series of 4-carbonylphenylboronic acid derivatives in the crystal state. Experimental and calculation results reveal that the electron-donating effect of substituents makes the phosphorescence lifetime longer by not only weakening the vibration relaxation of the excited triplet state but also increasing the energy of T1. Moreover, numerous intermolecular interactions for reducing nonradiative relaxation and the degree of the π-π stacking for stabilizing the triplet state are beneficial to the persistent RTP. The work is conducted to clarify the structure-property correlation of phosphorescent materials and design new persistent phosphors. Finally, an attempt is completed using phosphorescent materials to design two-dimensional or three-dimensional codes and anticounterfeiting applications.

Efficient Cascade Resonance Energy Transfer in Dynamic Nanoassembly for Intensive and Long-Lasting Multicolor Chemiluminescence.

Light emission induced by chemical reactions, known as chemiluminescence (CL), has been widely used for bioassays, biosensors, imaging, and illumination applications. Most known CL systems exhibit flash-type single-color light emissions, which limit their applications. Long-lasting multicolor CL in aqueous solutions is highly desirable, especially for biological applications, but remains a challenge. Herein, we report a simple strategy of achieving highly efficient cascade Förster resonance energy transfer (FRET) in the dynamic nanoassembly of β-cyclodextrin (β-CD), CL reagents, and fluorophores in aqueous solution, which emits intensive multicolor CL with adjustable wavelength within 410-610 nm. β-CD can bind CL reagents and fluorophores to form a dynamic nanoassembly. These nanoassemblies can bring the included luminescent intermediate and fluorophores into close proximity and proper alignment, which should greatly enhance the FRET efficiency between luminescent intermediate and fluorophores. Indeed, the cascade FRET efficiency in this supramolecular nanoassembly reaches up to 92%, which is comparable with the cascade FRET systems based on covalently linked donors and acceptors. By using hydroxypropyl methylcellulose as the thickener to slow the diffusion (to elongate the CL emission), and using Ca(OH)2 solid (a low solubility strong base) as buffer to maintain the pH in the optimal range for the CL reaction, this nanoassembly system has been further developed to achieve slow-diffusion-controlled catalytic CL reactions, which enables long-lasting multicolor CL in aqueous solution that is visible to naked eyes and lasts for more than 20 h. The multicolor CL systems can be used to prepare transformable two-dimensional multicolor codes for encryption application.

Current situation of innovation ability of clinical nurses in Guizhou Province and its influencing factors

Objective To explore the current situation of innovation ability of clinical nurses in Guizhou Province and its influencing factors so as to provide a theoretical basis for nursing managers to evaluate and carry out training for innovation ability among nurses. Methods In April 2019, this study selected totals of 24 Class Ⅲ hospitals, 50 Class Ⅱ hospitals and 60 ClassⅠ hospitals in Guizhou Province by stratified random sampling to carry out investigation with the method of cross-sectional survey. A total of 5 161 clinical nurses were randomly selected in each hospital according to the scale. Electronic questionnaire was designed, and WeChat link as well as two-dimensional code was developed by the Questioning Star software to investigation in the form of network. A total of 5 161 questions were collected and 5 145 of them were valid with 99.69% for the valid recovery rate. Excel was used to build the original database, SPSS 18.0 was used for analysis. Influencing factors were analyzed with the multiple linear regression. Results Among 5 145 clinical nurses in Guizhou Province, the total score of innovation ability was (129.63±24.30) with the intermediate level. Simple correlation showed that there were statistical differences in the scores of innovation ability among clinical nurses with different hospital levels, departments, ages, working lives, marital status, educational levels, positional titles, posts, monthly incomes, satisfaction with work, support for work from family members, employment forms, whether teaching and participating in scientific research (P<0.05) . Multiple linear regression analysis showed that the importantly influencing factors of innovation ability of clinical nurses included the satisfaction with work, support for work from family members, whether participating in scientific research, working lives, job title, hospital levels, whether teaching, monthly incomes with statistical differences (P<0.05) . Conclusions Clinical nurses of Guizhou Province have the intermediate level of innovation ability needed to be improved. Nursing managers should strengthen the innovation knowledge training and resource support for clinical nurses, encourage them positively to take part in continuing education so as to improve the innovation will and ability of clinical nurses in Guizhou Province. Key words: Nurses; Guizhou Province; Innovation ability; Influencing factors

Characterization and measure of infinite two-dimensional strong prefix codes

A set X⊆Σ++ of rectangular pictures over an alphabet Σ is a two-dimensional code if any picture over Σ is tilable in at most one way with pictures in X. Finite strong prefix codes were introduced as a family of decidable two-dimensional codes. We consider infinite strong prefix codes and give a characterization for the maximal ones based on the iterated extensions. Moreover, we study some properties related to the measure of these codes of pictures and prove some connections with the codes of strings.

Review of Post-registration Changes in the Life Cycle of Сholera Bivalent Chemical Vaccine (Review)

Introduction. The inevitable of post-registration variations due to the improvement of production processes and quality control related to the integration of the modern technological solutions, replacement of equipment, suppliers of raw, consumables and packaging materials, improvement of form release or composition, administrative changes, as well as obtaining new data on clinical efficacy and safety of immunobiological medicinal products (IMP) during post-marketing studies.Text. The purpose of this work is to analyze the post-registration changes in the life cycle of IMP «Сholera bivalent chemical Vaccine» produced by Russian State anti-plague Research Institute «Microbe», reflecting the harmonization of the documents of the registration dossier with the innovations of the Russian legislation, the optimization of production and quality control. First of all, the changes made to the registration documentation for IMP concerned the updating of the dossier in accordance with the adopted Federal laws and Resolutions of the government of the Russian Federation. The following changes related to the optimization of methods for controlling the limit content of impurities of substances used at different stages of antigen production. Also, the changes were associated with the improvement of consumer properties of the drug, namely the introduction of modern polymer packaging and several drug’s form release, convenient for use in practical health care institutions. The latest change of Pharmacopoeia enterprise article (PEA) R N001465/01-111119 regulates the application of identification means in the form of a two-dimensional bar code (QR-code) on the packaging of medicines, which is due to compliance with the requirements of article 67 «Information on medicines. The system of monitoring the movement of medicines» Federal law N 61 «Оn medicines circulation».Conclusion. Maintaining the required level of quality of IMP when changing production technology or control requires a comprehensive analysis of the proposed changes in order to make them in the documents of the registration dossier. At the same time harmonization of documents of the registration dossier with novelties of the Russian legislation is a necessary condition for implementation of production activity within the legal field.

A power function model for simulating creep mechanical properties of salt rock

In this paper, a new micro-creep model of salt rock is proposed based on a linear parallel bonded model (LPBM) using the two-dimensional particle flow code (PFC2D). The power function weakening form is assumed to describe the variation of the parallel bonded diameter (PBD) over time. By comparing with the parallel-bonded stress corrosion (PSC) model, a smaller stress fluctuation and smoother creep strain-time curves can be obtained by this power function model at the same stress level. The validity and adaptability of the model to simulate creep deformation of salt rock are verified through comparing the laboratory creep test curves and the Burgers model fitting result. The numerical results reveal that this model can be capable of capturing the creep deformation and damage behavior from the laboratory observations.

Crossed beam energy transfer in the presence of laser speckle ponderomotive self-focusing and nonlinear sound waves

Crossed beam energy transfer, CBET, is investigated by taking into account the speckle structure of smoothed laser beams that overlap in a plasma with an inhomogeneous flow profile. Using the two-dimensional simulation code Harmony, it is shown how ponderomotive self-focusing of laser speckles in crossing beams can significantly affect the transfer of energy from one beam to the other. The role of plasma flow in speckle self-focusing is investigated and revisited, in particular its consequences in terms of redirection and increasing angular spread of the laser beams due to beam bending and plasma-induced smoothing, respectively. In close-to-sonic flow, the onset of self-focusing in the beam speckle structure occurs at considerably lower beam intensities than expected for the case without flow. CBET and speckle self-focusing can, hence, occur together when two crossed beams with equal frequency resonantly exchange energy via their ponderomotively driven density perturbations flowing with sound speed. From the simulations, it is found that consequences of ponderomotive self-focusing can be expected above an average intensity threshold scaling as IL∼2×1014 W cm−2(λ0/1 μm)−2(Te/ keV ), with an impact on the spatial and temporal coherence of the transmitted light. The density perturbations due to the ponderomotive force of the crossing beams can locally be enhanced in self-focusing speckles, partly leading to shock-like structures. These structures eventually increase the effect of plasma-induced smoothing and are at the origin of the stronger angular spread.

System development and structure analysis of intelligent material handling robot

This paper analyzes the current popular machine vision modules and various manipulator in the market. It independently realizes the reading of two-dimensional code information, the recognition of material color and shape, and the intelligent grasping system of grasping. By screening the existing commercial motors and the whole positioning system composed of orthogonal encoder and all-directions wheel, it realizes the positioning and moving system that can plan the path autonomously. It realizes self-reading information, identifying, grabbing and stacking materials through the combination of the above systems. This paper uses MATLAB software to calculate and adjust the positioning speed and position, and carries out the overall design and three-dimensional modeling of the robot for the above modules, and it performs static load analysis on the main components of the robot through the Solidworks Simulation module, and performs simulation experiments. After summarizing the function integration of the robot, the author puts forward the application of scenario hypothesis, proposes the application promotion scope for this scenario hypothesis, and conducts the simulation experiment. The results show that the robot is simple in design, easy to implement and conduct mass production, and it is practical and reliable, and has good positioning, grabbing and recognition effects. It can be widely promoted in the field of automation.

Internal boundary conditions for a GPU-accelerated 2D shallow water model: Implementation and applications

Flood propagation in rivers is strongly influenced by the presence of bridges and other hydraulic structures. Among the available approaches for including these elements in numerical models, the adoption of Internal Boundary Conditions (IBC), given its ability to capture backwater, is suitable for field-scale analyses for flood hazard assessment. In this paper, the implementation of internal boundary conditions in the two-dimensional shallow water code named “PARFLOOD” is presented. The application to experimental and real test cases shows that the proposed IBC model can handle both low and high flow conditions for bridges, while being flexible for other types of structures (e.g. flow-through dams). Moreover, the model is computationally efficient (physical/computational time ratio around 20–30 for domains with ~106 cells), thanks to the code parallelization on GPU.

Braille learning materials for Braille reading novices: experimental determination of dot code printing area for a pen-type interface read aloud function

This study clarifies a previously established method in which Braille reading novices obtained Braille information aurally. Therein, users touched the vicinity of the Braille with a pen-type interface characterized by a Braille-to-voice function. Two-dimensional (2D) dot codes were printed on the Braille paper, and voice information corresponding to Braille was linked to these dot codes. This study aims to establish quantitative data regarding an acceptable size for the 2D dot code printing area. Nine Braille reading sighted novices, blindfolded and without Braille reading experience, were recruited to participate in an experiment, where they were asked to identify which of the six dots in a Braille character were missing, touch the pen-type interface to a sheet layered with the dot code printing area and TRUCT Braille, and evaluate the system’s effectiveness on a scale from 1 to 5. All participants correctly identified the missing dot. Participants gave the Braille-to-voice function an average effectiveness rating of 4.6/5.0, with a standard deviation of 0.7. A dot code printing area was determined to be 8 mm above and 10 mm below the midpoint between dots 2 and 5 of the Braille character, with a width of 16 mm from the midpoint of the Braille. Based on these results, design guidelines were identified for the dot code printing area to improve the success rate of obtaining voice information corresponding to the Braille with the pen-type interface equipped with the Braille-to-voice function. This has numerous potential applications in Braille education methods for Braille reading novices.

Experimental and numerical study on the interaction between holes and fissures in rock-like materials under uniaxial compression

Holes and fissures, regarded as typical defects, dominate a critical role in the mechanical behavior of rock. To investigate the effect of different horizontal distances L or L′ between the centroids of holes and fissures on the mechanical properties of pre-flawed rock-like material, two types of rock-like material specimens with holes and fissures are fabricated and subjected to uniaxial compression using Digital image correlation (DIC), Acoustic emission (AE) monitoring, Computerized tomography (CT) scanning, and two-dimensional Particle flow code (PFC2D). These results demonstrate that the peak strength, peak strain and elastic modulus all show a monotonically nonlinear decrease with increasing L or L′. Based on the DIC and CT methods, three rock bridge coalescence modes can be distinguished: tensile-tensile, shear-shear and tensile-shear modes. Moreover, the damage of the rock-like specimens, in the entire loading process, exhibits notable progressive failure characteristics in the strain localization zones. The crack initiation and coalescence cause the deformation curve to undergo a stress drop with a surge in the AE events and in the accumulated AE counts from AE monitoring. There is good agreement between the numerical simulation results and the experimental testing results, which further heighten the instability mechanism of defective rock engineering structures.

Investigating Dimensional Effects on Predicting Burning Rates of Heterogeneous Solid Propellants

The combustion of a randomly packed, heterogeneous propellant consisting of ammonium perchlorate and hydroxyl-terminated polybutadiene is investigated in a two-dimensional and three-dimensional numerical model to better understand the dimensional effects on the propellant burning rate. A ammonium perchlorate particle is set in a premixed hydroxyl-terminated polybutadiene binder and investigated using a two-dimensional model with finite-rate chemistry and detailed transport properties. The results from the detailed model are compared to two-dimensional and three-dimensional burning-rate codes with reduced chemistry. The gas-phase combustion chemistry is modeled using a reduced four-step mechanism developed from a detailed microscale model of ammonium perchlorate/hydroxyl-terminated polybutadiene combustion. Simple configurations of a single ammonium perchlorate particle and sandwich propellants at varying pressures are compared to determine leading-order effects of two-dimensional and three-dimensional approaches. The reduced chemistry models are then applied to real-world propellants for which a random packing algorithm is used to construct the ammonium perchlorate/hydroxyl-terminated polybutadiene propellant in a periodic cube for a given size distribution of spherical ammonium perchlorate particles and mass ratio of the oxidizer and binder. The decomposition of the ammonium perchlorate and hydroxyl-terminated polybutadiene on the surface is determined at discrete locations and is used to determine the average burning rate over a period of time. This approach combines a more detailed description of the gas-phase combustion processes, the condensed-phase morphology, and physics in a time-dependent simulation in hopes of developing a more predictive model of solid propellant combustion.