Big Grains Research Articles

Temperature-induced structure evolution in monocrystalline and polycrystalline cobalt via molecular dynamics simulations

The structure transition of metallic melt strongly depends on temperature and significantly influences the comprehensive properties. However, observing the structure change in experiments is still challenging. Here, molecular dynamics is used to study the melting process and microstructural evolution in single crystal and polycrystal cobalt (Co). The results indicate that the melting process of single crystal structure starts from 1870 K and lasts for a very short period, while the polycrystal melts from about 1760 to 1870 K. In polycrystal Co, the melting initially occurs in grain boundaries, and the melting temperature shows a positive correlation with grain size. An interesting solidification phenomenon occurs on the surface of big grains in the beginning of melting process. The coordination number increasing from 12 to about 13.4 near melting point proves the local expansion of the first coordination shell, indicating the structural evolution from long-range order to short-range order in the continuous heating process. The common neighbor sub-cluster index and Voronoi polyhedron demonstrate the short-range icosahedron structures, while these polyhedrons become polydisperse and isolated in Co liquid. The findings ignite the investigation of the liquid structure origin of crystal materials and extend the understanding of the atomic structure evolution in melting.

Achieving bimodal microstructure and enhanced tensile properties of Mg-6Sn-3Al-1Zn alloy by tailoring deformation amount during pack rolling

The Mg-6Sn-3Al-1Zn alloys were pack-rolled with various amounts of deformation at 400°C. The results indicated that a bimodal microstructure formed after pack-rolling. With the increase in the amounts of deformation, the average grain size of the small grains increased first and then decreased, while the average grain size of the big grains decreased. Both the volume fraction of twins and the average grain size of the alloy decreased with the increasing amounts of deformation, resulting in the improvement of the tensile properties of the alloy. When the amount of deformation was 65%, the mechanical properties of the alloys were optimal; the tensile strength, yield strength, and elongation-to-failure were 288 MPa, 188 MPa, and 15.7%, respectively.

Effects of grain size and seawater salinity on magnesium hydroxide dissolution and secondary calcium carbonate precipitation kinetics: implications for ocean alkalinity enhancement

Abstract. Understanding the impacts that mineral grain size and seawater salinity have on magnesium hydroxide (Mg(OH)2) dissolution and secondary calcium carbonate (CaCO3) precipitation is critical for the success of ocean alkalinity enhancement. We tested Mg(OH)2 dissolution kinetics in seawater using three Mg(OH)2 grain sizes (<63, 63–180 and >180 µm) at three salinities (∼36, ∼28 and ∼20). While Mg(OH)2 dissolution occurred more quickly the smaller the grain size, salinity did not significantly impact measured rates. Our results also demonstrate that grain size can impact secondary CaCO3 precipitation, suggesting that an optimum grain size exists for ocean alkalinity enhancement (OAE) using solid Mg(OH)2. Of the three grain sizes tested, the medium grain size (63–180 µm) was optimal in terms of delaying secondary CaCO3 precipitation. We hypothesise that in the lowest-grain-size experiments, the higher surface area provided numerous CaCO3 precipitation nuclei, while the slower dissolution of bigger grain sizes maintained a higher alkalinity and pH at the surface of particles, increasing CaCO3 precipitation rates and making them observable much more quickly than for the intermediate grain size. Salinity also played a role in CaCO3 precipitation, where the decrease in magnesium (Mg) allowed secondary precipitation to occur more quickly, similar in effect size to another known inhibitor, i.e. dissolved organic carbon (DOC). In summary, our results suggest that OAE efficiency as influenced by CaCO3 precipitation depends not only on seawater composition but also on the physical properties of the alkaline feedstock used.

The impact of titanium alloying on altering nanomechanical properties and grain structures of sputter-deposited cobalt for electromigration reliability enhancement

Cobalt (Co) has recently become a highlighted on-chip interconnection material for advanced metallization scheme of microelectronic circuits. Here, electromigration behaviors of sputter-deposited Co and Co(Ti; 0.9 at%) interconnection lines embedded in Si are comparatively studied. These lines were annealed (500 °C/30 min) prior to further accelerated electromigration testing under high current densities in the range of 3 × 107–9 × 108 A cm−2. A collection of the obtained electromigration failure lifetimes, current scaling factors and activation energies confirms a noticeable enhancement in the electromigration reliability of the Co lines by the added Ti. Results by scanning transmission electron microscopy (STEM) and nanoscratch testing reveal that 3–5 nm-sized Ti crystallites are uniformly dispersed in the Co-interconnect matrix, effectively inhibiting Co grain growth, promoting the formation of nanotwinned Co and elevating film’s mechanical properties for ensuring the electromigration reliability. With deteriorated hardness and adhesion energy, reduced planar defects and many big grains all spanning transversely the entire interconnect line, Co is vulnerable to electromigration failures, also giving accelerated thermally-induced interfacial diffusion and chemical reactions with the surrounding Si, as proven by depth-profiling secondary spectrometry and STEM analysis.

Ink engineering using 1,3-dimethyl-2-imidazolidinone solvent for efficient inkjet-printed triple-cationic perovskite solar cells

Ink engineering increases the quality and uniformity of large-scale perovskite films for efficient inkjet-printed perovskite solar cells (IJP-PSCs). The absorber layer in PSCs must be pinhole- and crack-free, highly uniform, with minimum defects, and have better optoelectronic properties, to improve PSC device performance. Herein, a different strategy, such as solvents with high boiling points (BPs), is used to modify the perovskite inks to obtain uniform and better-quality IJP-perovskite films. The perovskite film prepared with a 1,3-dimethyl-2-imidazolidinone (DMI) solvent is highly uniform (>96 %), thicker, with a smoother surface, and contains bigger grains than γ-butyrolactone (GBL) based IJP-perovskites. The DMI solvent-based IJP-PSC device shows a greater than 17.5 % power conversion efficiency (PCE), which is much higher than that possible with GBL-based devices (PCE ∼13.8 %). The better performance of the IJP-PSC device is mainly due to the film’s uniformity, large grains, and well-formed structures, which reduce the occurrence of specific chemical reactions within the perovskite material. The presented ink engineering strategy to develop highly uniform IJP perovskite films has the potential to be applied to perovskite solar modules.

Nanoengineering approach toward ultrahigh power factor Ag2Se/polyvinylpyrrolidone composite film for flexible thermoelectric generator

Flexible thermoelectric (TE) generators (F-TEGs), able to harvest heat energy from the human body, are considered to be competitive energy supply devices for wearable and implantable electronics. Herein, we fabricate Ag2Se/polyvinylpyrrolidone (PVP) films on nylon membranes via a novel nanoengineering approach: First, small amount Ag nanoparticles decorated Ag2Se nanowires (NWs) coated with a nanolayer of PVP are synthesized via a Se NW template method, and the Ag nanoparticles react with small amount Se residues at the core of the Ag2Se NWs during hot-pressing and form Ag2Se nanograins rich in defects embedded in big Ag2Se grains. The Ag2Se nanograin has a different orientation from the big Ag2Se grain; hence, the interface between the Ag2Se nanograin and the big Ag2Se grain enhances the phonon scattering but almost does not affect the transport of carriers. An optimized film exhibits a maximum power factor of 2478 ± 67 μW m−1 K−2 (corresponding ZT ∼ 1.05) at 300 K, which is one of the highest values reported for flexible Ag2Se films. The excellent TE properties of the film are attributed to its unique microstructure: highly densified, coherent/semi-coherent Ag2Se grains, embedded Ag2Se nanograins, and a very small amount of PVP located at nanopores. Besides, the film shows good flexibility: after 1500 times bending along a rod with a radius of 4.0 mm, the electrical conductivity still maintains 90.9 %. Furthermore, a 6-leg F-TEG assembled with the optimal film generates a maximum power of 4.58 μW (corresponding power density of ∼ 31.2 W m−2) at a temperature gradient of 38.7 K. This work provides an efficient strategy for the fabrication of ultrahigh-performance Ag2Se-based flexible TE films.

Improvement of Efficiency in Kesterite Solar Cells by Intentionally Inserting a Thin MoS2 Layer into the Back Interface.

A Mo(S,Se)2 interfacial layer is formed inevitably and uncontrollably between the Mo electrode and Cu2ZnSn(S,Se)4 (CZTSSe) absorber during the selenization process, which significantly influences the performance of CZTSSe solar cells. In this work, an ultrathin MoS2 layer is intentionally inserted into Mo/CZTSSe to reduce the recombination and thus optimize the interface quality. It is revealed that the absorber exhibits a continuous and compact morphology with bigger grains and remarkably without pinholes across the surface or cross-sectional regions after MoS2 modification. Benefitting from this, the shunt resistance (RSh) of the device increased evidently from ∼395 to ∼634 Ω·cm2, and simultaneously, the reverse saturation current density (J0) realized an effective depression. As a result, the power conversion efficiency (PCE) of the MoS2-modified device reaches 9.64% via the optimization of the thickness of the MoS2 layer, indicating performance improvements with respect to the MoS2-free case. Furthermore, the main contribution to the performance improvement is derived and analyzed in detail from the increased RSh, decreased J0, and diode ideality factor. Our results suggest that the Mo/CZTSSe interface quality and performance of CZTSSe solar cells can be modulated and improved by appropriately designing and optimizing the thickness of the inserted MoS2 layer.

Extended hygrothermal characterization of unstabilized rammed earth for modern construction

Although hygrothermal properties of rammed earth represent great potential for improving thermal comfort during hot summers, still little knowledge is available about this topic. The literature lacks complete sets of hygrothermal characteristics of rammed earth, although they are fundamental for heat and moisture transfer modeling necessary to predict earthen building performances. The present work reports the results of a large collaboration between four academic laboratories in order to obtain an extended hygrothermal characterization of rammed earth, focusing on the material used in a modern construction in Lyon, France. The aim of the article is to provide for the same kind of soil an extend characterization on a large span of relative humidity to provide complete set of material properties for heat and moisture transfer simulation. The hygrothermal measurements cover adsorption and desorption isotherm, intermediate isotherm loop, specific heat capacity, dry thermal conductivity, moisture-dependent thermal conductivity and water vapor resistance factor for a large span of relative humidity. In addition, the capillary rise test was performed to estimate the liquid transport coefficient for suction and redistribution. The results show that variations in the density of the samples have a low impact on sorption isotherm, while they have a non-negligible impact on thermal conductivity and water vapor permeability. Surprisingly, variations in the grain size distribution do not produce a significant modification in the sorption isotherm, while hysteresis slightly reduces when bigger grains are added to the soil composition. Approximation of empirical model coefficients for the determination of moisture-dependent thermal conductivity is proposed for rammed earth materials.

Dynamical charging of interstellar dust particles in the heliosphere

Interstellar dust (ISD) particles penetrate the solar system due to the relative motion of the Sun and the local interstellar cloud. Before entering the heliosphere, they pass through the heliospheric interface – the region of the solar wind interaction with the interstellar plasma. The size distribution and number density of dust grains are modified in the interface essentially. The modification depends on the charging of the dust particles along their trajectories. In this paper, we present modeling results of the charging of ISD particles passing through the heliospheric interface. The main physical processes responsible for the charging within the heliospheric conditions are the sticking of primary plasma particles, secondary electron emission, photoemission, and the effects of cosmic ray electrons. We consider two methods to calculate the electric charge of ISD particles based on (1) the classic steady-state assumption that the charge depends only on local plasma and radiation conditions and (2) the dynamical computation of charge along the particle trajectory. We demonstrate that the steady-state assumption is quite justified to model trajectories and number density distributions of relatively big ISD grains (radius of 100 nm and larger) penetrating the heliosphere. The estimates show that ISD grains of these sizes require less than 0.25 years (distance of ≈1 au) after transition from the LISM into the heliosphere to reach an equilibrium. For small particles ( radius of 10 nm), the dynamical computation of charge influences the trajectories and modifies the number density substantially. The dust density accumulations are distributed within a more elongated region along the heliopause in case of dynamically changed charge as compared with the use of a steady-state charge approximation. As a result, the magnitudes of number density at the points of density features differ several times between the results obtained by the two considered approaches.

The simulation of microstructural evolutions in friction stir additive manufacturing

Both recrystallization and solid state phase transformation take key role for the determination of final mechanical properties in friction stir additive manufacturing (FSAM) of titanium alloy. Monte Carlo model is developed to simulate the microstructural changes and a two scale strategy is used to simulate both the recrystallization and the solid state phase transformation in FSAM of duplex titanium alloy. Results indicate that the selection of the building direction can lead to different temperature variations in FSAM due to the different heat accumulations. Lower temperature leads to lower cooling rate in FSAM. This is the reason that the volume fraction of α phase is decreased when the process temperature is decreased. Higher temperature leads to the formation of bigger grains when the rotating speed is increased or the transverse speed is decreased.

PRELIMINARY RESULTS REGARDING THE OPTIMAL SEED RATES OF SOME WINTER WHEAT VARIETIES

Before to extended on large surfaces, the new wheat varieties need to be examinate to finding their requirements regarding technological components, like planting density. In accord with this demand, during the agricultural year 2021 – 2022 were tested at Oradea, in north-west of Romania, our news registered varieties Dacic and Biharia, beside of other 23 Romanian or foreign varieties of wheat, at seven seeding rates:200, 300, 400, 500, 600, 700 and 800 seeds/m2. Statistical processing of the yield and wheat features were dan by usual correlation (Pearson), Spearman rank correlations, the calculations of linear and quadratic equations of correlations between grain yield and seeding rate and calculation of linear, quadratic, exponential and logarithmic trend between the same characters, the trend of the most significant determination coefficient being utilised in graphical transpositions. Some genotypes (Voinic, Bogdana, Dacic, Cezara and Crisana) have their best ranks of yield at low densities while other (Gabrio, Consecvent, Anapurna and Abundent) at the greatest ones. Taking in consideration the average of ranks, the genotype Consecvent has the best average position, followed by Gabrio, Abundent, Bogdana and Voinic. These five genotypes have a good capability to adjust their yields components to vary densities of plants. At low densities (200, 300, 400 and 500 germinal seeds/m2), the genotypes yield ranks are comparable but at high densities (more than six hundred seeds/m2), the ranks are stronger effected by density. Every genotype has an optimum seed density, depending on its capacity to tolerate or no high density: Crisana- 500 seed/m2, Biharia- 600 seed/m2, Consecvent- 600 to 700 seed/m2, Anapurna- 800 seed/m2, etc. Some varieties, like Voinic, have a pour response to seeding rate, they yielded well even at small density, being able to compensate the reduced density by tillering capacity, number of grains/spikes, better test weight and bigger grain size.

Silicon Carbide–Silicon Nitride Refractory Materials: Part 1 Materials Science and Processing

Silicon carbide and silicon nitride materials were intensively studied in the end of the past century, yet some aspects of its physical chemistry require investigation. The strength characteristics of Si3N4-SiC refractories are moderate; however, these materials sometimes demonstrate “stress–strain” behavior, more typical for composite materials than for the brittle ceramics. These materials may be considered to be ceramic composites because they consist of big grains of silicon carbide surrounded by small grains of silicon nitride, with strict interfaces between them. There is no direct certainty whether Si3N4-SiC compositions may be called composite materials or brittle ceramic materials from the viewpoint of mechanics and strength. The balance of α/β modifications of silicon nitride in Si3N4-SiC composite material and, the occurrence and the role of silicon oxynitride Si2ON2 are also a matter of scientific interest in processing of Si3N4-SiC composite material. The same may be said about the particles of silicon nitride between the grains of silicon carbide—there is no direct understanding whether silicon nitride grains will be isometric grains or needle-like crystals.

Influence of process parameters on surface properties and corrosion resistasnce of Inconel 625 coating prepared by laser cladding

To obtain good corrosion resistance and save cost, Inconel 625 coating was prepared by laser cladding with different process parameters, and the Inconel 625 powder play as feed material. The influence of powder feed rate (Vp), scan rate (Vs) and laser power (P) on the surface waviness (Wa) and effective height (he) of the cladding was analyzed. The results indicate that the Wa and he increase with the increase of Vp, while decrease with the increase of Vs. In addition, the P has positive influence on the he. When the P is lager than 1.0 kW, P boost the increase of Wa. Otherwise the influence is opposite. The microstructure of the cladding exhibiting relative good formation quality was studied using X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS). It demonstrates that the cladding is mainly composed of γ-Ni matrix and laves phase. Many coarse columnar and cellular crystals are distributed at the previous clad near the fusion line, while the other side is mainly composed of fine and dense columnar crystal. The process parameters have influence on size of grains and laves phase. For the relative good formation quality, the most positive Ecorr, the smallest Icorr, and largest Epit, the cladding marked No.3 possesses more outstanding comprehensive corrosion resistance than others. It is concluded that big grains size and less number of laves phase is benefit to the corrosion resistance.

Effects of in situ phase reaction of η M12C and M6C on microstructure and mechanical properties of tungsten heavy alloy via spark plasma sintering

Spark plasma sintering (SPS) which densifies metallic or ceramic powders in few minutes can reduce sintering temperature, increase relative density, and inhibit grain growth in the consolidated materials. The phase reaction during the short SPS process is often ignored. In this work, a very important tungsten heavy alloy (WHA), 90 W − 7Ni − 3Fe (wt%) alloy, is taken as a typical example to demonstrate how in situ formation of η M12C or M6C influences the microstructural evolution and mechanical strength of the alloys SPSed at 1000–1200 °C through experimental characteristics combined with first−principles calculation. The results show that the in situ phase reaction from η M12C to M6C carbides plays a key role in the mechanical properties of WHAs, or oven more important than the relative density and grain size. The phase reaction from η M12C to M6C not only alters the phase composition of WHAs, but also lead to distinct interface relationship among matrix W, binder γ − (Ni, Fe) and η carbide phases. A maximum bending strength of 1268 ± 73 MPa was achieved after the phase reaction at 1200 °C, despite the lower relative density (95.8 ± 0.7%), smaller Young's modulus (209 ± 11 GPa) and bigger grain size (2.6 ± 1.0 μm).

The influence of tool rotational speed on microstructure and mechanical performance of dissimilar FSLW

FSLW is a novel solid-sate joining process in aircraft assembly technology that has offered superior welding quality to the joining of aluminum alloy. Concerning the success of FSLW light metal alloys coupled with lower operating costs due to improved energy efficiency and virtual lack of a consumable has emphasized the need to examine AA 2024-T4 and AA 7075-T6 based on different tool rotational speeds (RSs). This research examined the three important determinants of FSLW: cross-section morphology, microstructure behavior, and mechanical performance (lap shear failure load and fracture location) to realize the quality and reasonable experiment of the welding technique. The cross-section of the lap joint is investigated in this experiment; it is evident that the maximum temperature is found in the stir zone, and the shape looks like a bowl type. Further, it is found that tool RS does not have an influence on the effective sheet thickness, but it influences the effective lap width. With the increased RS, the effective lap width increased first and then decreased. Concerning grain size analysis, the bigger grain size was observed in the heat-affected zone, and the smaller grain size was observed in the thermomechanical-affected zone. According to the mechanical performance analysis, the lap shear failure load increased and then reduced with increased RS.

Microstructure morphology and tensile properties of 9Cr-ODS steels added different Y2O3 contents

Oxide dispersion strengthened (ODS) steels are considered to be the promising structural material candidates for Generation IV fission reactors, fusion reactor applications, new accident-tolerant fuel (ATF) cladding materials. In this study, different contents of Y2O3 were added into 9Cr-ODS steels to realize different Y/Ti atomic ratios. The microstructure of samples, kinds, number densities and size distribution characteristic of nano-scale oxide-precipitates formed in the 9Cr-ODS steel samples were investigated by synchrotron radiation SAXS, XAFS spectrum and TEM, explained the effect of Y2O3 contents on microstructures of 9Cr-ODS steel samples. The tensile properties of the 9Cr-ODS steel samples with different Y2O3 contents were also measured simultaneously. The experimental data show when Y2O3 content is 0.3%, the density of Y-Ti-O nano-clusters is the highest, reaching to 1.39×1024 /m3. At the same time, the number density of Y-Ti-O nano-clusters is the lowest, if the Y2O3 content is 0.7%. The XAFS result of 0.7% Y2O3 sample is close to a Y2O3 reference sample. The 0.3% Y2O3 has a bigger grain size than the other two samples. The 9Cr-ODS steels with Y2O3 content of 0.3% exhibit the highest tensile strength and higher ductility properties.

Additive engineering enables efficient, stable perovskite solar cells

Perovskite films with additives have bigger grains and better crystallinity, decreasing the density of defects.

LG5, a Novel Allele of EUI1, Regulates Grain Size and Flag Leaf Angle in Rice.

Grain size and flag leaf angle are two important traits that determining grain yield in rice. However, the mechanisms regulating these two traits remain largely unknown. In this study, a rice long grain 5 (lg5) mutant with a large flag leaf angle was identified, and map-based cloning revealed that a single base substitution followed by a 2 bp insertion in the LOC_Os05g40384 gene resulted in larger grains, a larger flag leaf angle, and higher plant height than the wild type. Sequence analysis revealed that lg5 is a novel allele of elongated uppermost internode-1 (EUI1), which encodes a cytochrome P450 protein. Functional complementation and overexpression tests showed that LG5 can rescue the bigger grain size and larger flag leaf angle in the Xiushui11 (XS) background. Knockdown of the LG5 transcription level by RNA interference resulted in elevated grain size and flag leaf angle in the Nipponbare (NIP) background. Morphological and cellular analyses suggested that LG5 regulated grain size and flag leaf angle by promoting cell expansion and cell proliferation. Our results provided new insight into the functions of EUI1 in rice, especially in regulating grain size and flag leaf angle, indicating a potential target for the improvement of rice breeding.

Fabrication and Characterization of p-SnS/n-Si Solar Cell by Thermal Evaporation Technique and the Effect of Ag-doped on Its Efficiency

Tin sulfide (SnS) is a promising material for solar cell absorber layer applications due to its low cost, ease of availability and lower toxicity than other semiconductor materials, used for the same purpose. Thermal evaporation was used to deposit thin-film solar cells with SnS on glass and silicon substrates, with minimal silver doping ratios (0.02, 0.04 and 0.06) wt.% and thickness in the 125-nm range. Surface morphology, crystallite size and optical and electrical characteristics have all been thoroughly investigated. XRD analysis revealed that /both the undoped and Ag-doped SnS films were well crystallized, with an orthorhombic structure and polycrystalline nature. The (111) plane was the preferred orientation. Due to the low doping ratios, there are no silver-specific peaks. Additionally, the Scherer formula was used to calculate the crystallite size, which showed an increase from 3.7096 to 10.4716[Formula: see text]nm. AFM images showed that SnS: Ag (6[Formula: see text]wt.%) film has bigger grains than other samples. The Hall Effect test revealed that the film is p-type conductivity. The optical bandgap values were found to be in the (2.6–1.7[Formula: see text]eV) range. All of the SnS films had an absorption coefficient of more than [Formula: see text] above the fundamental absorption edge. These polycrystalline and highly absorbing SnS thin films can be used to make heterojunction solar cells. The wider energy gap of the produced films, which allows more light to reach the solar cell junction, was found to be connected to changes in thin film microstructure characteristics. The efficiency of the prepared solar cells reached 5.4% for the 6[Formula: see text]wt.%Ag-doped SnS/Si solar cell, with a fill factor of 0.46.

<i>Agrobacterium</i>-mediated transformation efficiency and grain phenotypes in six <i>indica</i> and <i>japonica</i> rice cultivars

Plant transformation and regeneration have been continuously developed for the past four decades. In rice (<italic>Oryza sativa</italic> L.), <italic>Agrobacterium</italic>-mediated transformation has high efficiency in<italic> japonica</italic> and some <italic>indica</italic> cultivars using mature seeds and immature embryos. However, these protocols have low transformation efficiency in the latest <italic>indica</italic> cultivar that has been developed in South China since 2010. Here, we explored plant culture regeneration of the high-quality and high-yield <italic>indica</italic> cultivar Nanguizhan (NGZ) through CRISPR/Cas-based genome editing and traditional overexpression transformations. We compared transformation efficiency in this cultivar to four other widely-used <italic>indica</italic> cultivars and one <italic>japonica</italic> cultivar using mature seeds and the gene <italic>Grain Size and Number 1</italic> (<italic>GSN1</italic>) as a case study. We observed universe smaller grain size in overexpression lines and bigger grain size in gene-editing lines among different cultivars. NGZ phenotypes make it an excellent model in which to investigate gene functions. We also examined the single nucleotide polymorphism (SNP) distribution and differences in expression levels of regeneration-related genes in calli, possibly revealing the source of NGZ's advantages in <italic>Agrobacterium</italic>-mediated transformation. These results shed light on the advanced application of NGZ in gene editing and overexpression transformation related to grain improvement, contributing to the "rice breeding 4.0 era".