Diffusion Stage Research Articles

Chaos blended cellular automata on fractals: the effective way of reconfigurable hardware assisted medical image privacy.

In more recent times data continues to be generated at a very unprecedented scale. This is a result of the pervasive nature of modern-day digitisation. As such, it is absolutely critical that this data only be accessed by the trusted parties concerned in an effort to maintain the privacy of individuals. One particular type data that could severely compromise the identity and privacy of an individual is ‘medical data’. With a focus on medical images, this work proposes a novel ‘fractalized’ chaos-cellular automata encryption scheme, implemented on Cyclone IV EP2C35F672C6 FPGA, resulting in a hardware-based concurrent security solution. The scheme entails three stages of diffusion, which arise from different mechanisms. In tandem with the diffusion process is the “On the Fly” process of confusion governed by a Linear feedback Shift Register (LFSR), all of which in implemented by applying the nature of fractals. The security architecture occupies 16,351 Logic Elements (LEs) with 230 registers on the target FPGA with the power dissipation of 133.39 mW. Further, the encryption achieves near zero correlation with the average entropy of 15.17156 that ensures the statistical properties. In addition, the security framework requires 12.13 ms to encrypt a 256 × 256 × 16 DICOM image which results in the throughput of 86.44 Mbps. The proposed encryption resists the brute force attack and chosen plain text attack by achieving a very large span of keyspace.

NE-trending transtensional faulting in the Pearl River Mouth basin of the Northern South China Sea margin

The joint tectonic interaction to the Pearl River Mouth Basin (PRMB) between the collision of the Indo-Australia and Eurasian plates and the subduction of the Pacific Plate (the Philippine Sea Plate) made the present-day complex structures. The basement of the northern South China Sea (SCS) margin has an affinity to the South China Block basement, which has experienced multi-stage tectonic events. The divisions of tectonic units and events, and dynamics of the PRMB are always controversial. Based on the structural analysis to seismic interpretation, and taking the Xijiang, Baiyun and Liwan sags as examples, we conclude that the PRMB sub-basins are transtensional basins. The PRMB can be subdivided into three Cenozoic structural layers in profiles from bottom to top: Early Cenozoic graben, Mid-Cenozoic half-graben and Late Cenozoic depression. In the early Cenozoic (∼55–45 Ma), the Izanagi-Pacific Mid-ocean Ridge subducted beneath the East Asian Continental Margin, and the study area entered the NNW-SSE diffusive extension stage, forming the ENE-trending wide rift. In the middle Cenozoic (45–25 Ma), the Paleo-Pacific Plate subducted from NNW to WNW under the East Asian Continental Margin, and the Mesozoic structure was activated, showing NE-NNE-trending dextral faulting. In the late Cenozoic (since 25 Ma), the Philippines Sea Plate wedged WNW-ward, and the South China Sea began to subduct eastward under the Philippines Sea Plate. Combined with the extrusion of the Indochina Block, the regional stress field was dominated by the NNE-SSW-directed extension, and the NW-trending sinistral structures developed.

The influence of organizational structure on value-based management sophistication

Despite the widespread use of value-based management (VBM) in European companies, studies investigating the reasons for the differences in its sophistication remain scarce and are predominantly focused on environmental and intra-organizational aspects. Since the structure of a firm as a major organizational determinant is assumed to have a considerable impact on the fit between an organization and an administrative innovation, we examine the influence of organizational structure on VBM sophistication. Based on survey data from 117 large for-profit firms in Austria, Germany and Switzerland, our findings indicate that the organizational structure variables centralization, formalization and horizontal integration are positively associated with VBM sophistication. Our data provide insight into the interconnection of specific organizational structure variables on particular VBM subdimensions. The findings illustrate that a high level of centralization is positively associated with the political fit of an organization with VBM, while vertical differentiation seems to have a negative relationship with the cultural fit with VBM. High levels of formalization and horizontal integration indicate a technical, political and cultural fit with VBM, which helps to achieve and prevail a high extent of VBM implementation in late diffusion stages. While firms that are listed on the stock market show a positive association with VBM sophistication, the interconnections of organizational structure variables with VBM sophistication appear both in listed and unlisted firms.

Effect of PrFe alloy grain boundary diffusion on coercivity and microstructure of sintered Nd-Fe-B magnets

A Ga-containing Nd-Fe-B magnet was diffused by Pr70Fe30 alloys. After diffusion, the coercivity of the diffused magnet increased from 15.77 kOe to a maximum of 22.20 kOe. Changing the diffusion source mass ratio resulted in a different grain boundary microstructure. The grain boundary structure improved in the surface region. The distribution of Ga was optimized to form continuous RE6Fe13Ga phases in the grain boundaries by diffusing Pr70Fe30 alloys. The improvement in coercivity is mainly attributed to the optimized grain boundary structure and the continuous RE6Fe13Ga phase. Furthermore, the structural changes and their causes at different stages of diffusion were analyzed.

Convergence Analysis of the Variational Operator Splitting Scheme for a Reaction-Diffusion System with Detailed Balance

We present a detailed convergence analysis for an operator splitting scheme proposed in [C. Liu et al.,J. Comput. Phys., 436, 110253, 2021] for a reaction-diffusion system with detailed balance. The numerical scheme has been constructed based on a recently developed energetic variational formulation, in which the reaction part is reformulated in terms of the reaction trajectory, and both the reaction and diffusion parts dissipate the same free energy. The scheme is energy stable and positivity-preserving. In this paper, the detailed convergence analysis and error estimate are performed for the operator splitting scheme. The nonlinearity in the reaction trajectory equation, as well as the implicit treatment of nonlinear and singular logarithmic terms, impose challenges in numerical analysis. To overcome these difficulties, we make use of the convex nature of the logarithmic nonlinear terms, which are treated implicitly in the chemical reaction stage. In addition, a combination of a rough error estimate and a refined error estimate leads to a desired bound of the numerical error in the reaction stage, in the discrete maximum norm. Furthermore, a discrete maximum principle yields the evolution bound of the numerical error function at the diffusion stage. As a direct consequence, a combination of the numerical error analysis at different stages and the consistency estimate for the operator splitting results in the convergence estimate of the numerical scheme for the full reaction-diffusion system.

Modeling the Jump-like Diffusion Motion of a Brownian Motor by a Game- Theory Approach: Deterministic and Stochastic Models

Methods of paradoxical games are used to construct a stochastic hopping model of Brownian ratchets which extends the well-known analogous deterministic model. The dependencies of the average displacements of a Brownian particle in a stochastic ratchet system on a discrete time parameter are calculated, as well as the dependencies of the average ratchet velocity on the average lifetimes of the states of the governing dichotomous process. The results obtained are compared with both the results of modeling a similar deterministic model and the results of a known analytic description. While for the hopping analogue of the deterministic on-off ratchet, the time dependence of the displacement contains periodically repeated hopping changes when the potential is switched on and plateau of the diffusion stage of the motion when it is switched off, the stochastic dependencies, that are of an averaged character, are monotonous and do not contain jumps. It is shown that, with other things being equal, the difference in the results for the hopping ratchet model driven by the stochastic and deterministic dichotomous process of switching the potential profiles (game selection) is more pronounced at short lifetimes of the dichotomous states and vanishes with their increase.

Community Empowerment Program Through Transformation Process In Samarinda Islamic High School

<p><em>The main task of universities in developing science is not only teaching and research, but also community empowerment. In this study, the question is how the Samarinda Islamic High School in carrying out community empowerment activities using social transformation or change? The type of research in this study is descriptive analytical research, because the researcher describes the transformation or social change first and then analyzes the social changes carried out by the Islamic High School. With the method of transformation or social change in the form of stages of invention, diffusion and consequences. the process of social change with these three, the Islamic High School conducts a study first by looking at and studying the behavior of the community in relation to change. Social change is a process where there is a change in the structure and function of a social system. These changes occur as a result of the inclusion of reform ideas so that they are beneficial to the community. Social change in society is not an outcome or a product but a process. In the end, the change is a joint decision taken by community members. These changes occur as a result of the inclusion of reform ideas so that they are beneficial to the community. Social change in society is not an outcome or a product but a process. In the end, the change is a joint decision taken by community members. These changes occur as a result of the inclusion of reform ideas so that they are beneficial to the community. Social change in society is not an outcome or a product but a process. In the end, the change is a joint decision taken by community members.</em></p>

Tokenization, blockchain and web 3.0 technologies as research objects in innovation management

Tokenization, blockchain and web 3.0 technologies as research objects in innovation management

Mineralization characteristics of coal fly ash in the transition from non-supercritical CO2 to supercritical CO2

The accelerated mineralization of fly ash is a potential way to achieve CO2 emissions reduction. However, the slow reaction at the diffusion control stage is the bottleneck. Due to the strong diffusion of supercritical CO2, it has been to strengthen mineralization, but the degree of improvement in mineralization efficiency and the changes that take place in the transition from non-supercritical to supercritical CO2 are not clear. In the mineralization process, CaO in the ash reacts with CO2 to form CaCO3. In order to exclude the influence of other alkaline oxides, powdered and block CaO were used to research the mechanism, and experiments were then carried out on samples of fly ash with different CaO content. Firstly, powdered CaO was used to conduct dry and wet mineralization experiments. In dry mineralization, the mineralization efficiency of the process changes in two stages as the pressure increases, first undergoing a gentle-increase and then a rapid one. Diffusion depth experiments on block CaO show that the supercritical diffusion depth is higher than the non-supercritical diffusion depth by a factor of 1.22, indicating that supercritical CO2 can improve the degree of mineralization in diffusion stage. The presence of water could promote mineralization. In wet mineralization, the efficiency of the process changes in three stages as the pressure increases, with first a gentle increase then a more rapid one and finally an attenuated rate of increase. The supercritical mineralization efficiency at 8 MPa was 55.27%, a factor of 2.09 larger than for non-supercritical mineralization at 3 MPa (26.39%). This is because that supercritical CO2 has increased the diffusion and greatly improved solubility in water. The results of DFT calculations show that H2O can promote the adsorption of CO2 by CaO, which is one of the reasons why water promotes mineralization. Finally, wet mineralization experiments on fly ash show that at 8 MPa, the mineralization efficiencies of HB, SD, SX and YN fly ashes are 1.94, 1.30, 2.03 and 1.62 times their values at 3 MPa. Although the difference in efficiency is affected by the CaO content, supercritical CO2 can effectively improve the mineralization efficiency.

Physical and Mathematical Models of Target Component Extraction from Rectlinear Capillaries

The extraction of the solid component from the rectilinear capillary has been investigated. The presence of two extraction zones (convective and molecular diffusion) was confirmed. The effect of the system vacuumizing on the extraction rate has been studied. The convection zone during vacuumizing was found to be increased due to the appearance of the vapor phase bubbles. The mass transfer coefficients for the convective zone have been determined. A mathematical model of the molecular diffusion stage is given, taking into account the nonlinear change in the component concentration in the liquid due to the displacement of the extraction boundary. The molecular diffusion coefficients in the capillary have been determined.

Spreading behavior of Sn droplets impacting Cu and stainless steel substrates

With the development of droplet 3D printing, thermal spraying, spray molding, and other technologies, the collision diffusion process of metal droplets and metal substrates has become a key aspect in controlling these processes. This study used Sn droplets as the research object. Using a pneumatic pulse jet device, molten Sn droplets were impinged on the surface of copper and stainless steel substrates. The impact process was recorded by high-speed photography. The diffusion diameter and solid-liquid contact angle were measured from these images, revealing the difference in the diffusion of Sn droplets on different surfaces. This explains the difference in the droplet diffusion ability from the perspective of driving energy. The entire impact process and final morphology were considerably similar when the substrate temperature was lower than the melting point of Sn. When the substrate temperature was higher than the melting point of Sn, the entire diffusion behavior of the tin droplet from contacting the substrate to the steady state was investigated in stages. From the driving energy analysis, it was observed that the Sn droplet is mainly driven by its internal kinetic energy in the initial stage of diffusion. When the diffusion diameter approached the maximum value, the kinetic energy of Sn droplets gradually dissipated; the surface energy and viscous force work gradually increased, and the diffusion changed from a linear diffusion state to a slow diffusion state. Simultaneously, the surface energy and viscous force of the droplet played a key role. The adhesion of Sn droplets to the surface of the stainless steel substrate was very small, and the interface did not react, which caused the Sn droplets to shrink significantly on the stainless steel surface during the retraction stage.

Laboratory investigation on blending process of reclaimed asphalt mixture

With the extensive application of hot recycling technology in maintenance of asphalt pavement, there is a concern on the blending between reclaimed asphalt pavement (RAP) binder and virgin binder. Two main stages, viz. the mobilization stage of RAP binder and the diffusion stage of virgin binder, in the blending process between RAP and virgin binder are investigated in this study. In order to quantify the mobilization rate of RAP binder, a blending chart relating RAP binder content to carboxyl index (CI) of blended binder was established by using Fourier transform infrared spectrometer (FTIR). The effects of RAP particle size, RAP temperature and mixing sequence were taken into account in laboratory experiment. The diffusion of virgin binder was studied by using the tracing method. Cobaltous (Co) naphthenate solution as a tracer was blended with the virgin binder. Based on the distribution of Co element in RAP binder detected by scanning electron microscope equipped with energy dispersive spectrometer (SEM/EDS), an index was proposed to quantify the diffusion degree of virgin binder. The obtained results showed that the proposed indicators could well reflect the variation of mobilization rate and diffusion degree under different test conditions and can be used to comprehensively evaluate the blending efficiency between RAP binder and virgin binder.

CO2 Hydrate dissolution rates in unsaturated water quantified with laboratory experiments

Measuring the dissolution rates of CO2 hydrates in marine environments is urgently needed because CO2 hydrate is a powerful means in CO2 ocean sequestration as well as a product of CO2-CH4 gas replacement in hydrate exploitation. The stability of CO2 hydrates is a significant index to evaluate the feasibility of gas hydrate technologies. It is generally agreed that the dissolution of hydrates is diffusion-controlled rather than reaction-controlled. In this work, the dissolution rates of CO2 hydrates in sediments under a variety of experimental conditions were calculated by the CO2 fluxes and mass balance. The in situ CO2 concentrations in static and flowing water layers were measured by Raman spectroscopy. Firstly, the dissolution rates of CO2 hydrate in sediments in different diffusion stages were 314 to 3.5 cm/year and 194 to 1.2 cm/year in static deionized water and brine layer, respectively. The CO2 hydrate underwent a rapid dissolution stage in the beginning of the experiment. Then the dissolution rate slowed down because of the decreasing concentration gradients. The difference of dissolution rates between deionized water and brine is related to the CO2 solubility in different solutions. CO2 hydrates covered with sediments dissolved much slower than hydrates dissolved in direct contact with water layers due to the increased diffusion boundary layers and the decreased diffusion coefficients. Additionally, the dissolution rates of CO2 hydrate that exposed to a variety of flow rates showed a strong velocity dependency. In this work, the dissolution rates of CO2 hydrate under flowing water layers ranged from 5.6 to 365 cm/year with volume flow rates ranged from 1.01 to 8.57 ml/min.

Optical Coherence Elastography as a Tool for Studying Deformations in Biomaterials: Spatially-Resolved Osmotic Strain Dynamics in Cartilaginous Samples.

This paper presents a recently developed variant of phase-resolved Optical Coherence Elastography (OCE) enabling non-contact visualization of transient local strains of various origins in biological tissues and other materials. In this work, we demonstrate the possibilities of this new technique for studying dynamics of osmotically-induced strains in cartilaginous tissue impregnated with optical clearing agents (OCA). For poroelastic water-containing biological tissues, application of non-isotonic OCAs, various contrast additives, as well as drug solutions administration, may excite transient spatially-inhomogeneous strain fields of high magnitude in the tissue bulk, initiating mechanical and structural alterations. The range of the strain reliably observed by OCE varied from ±10−3 to ±0.4 for diluted and pure glycerol, correspondingly. The OCE-technique used made it possible to reveal previously inaccessible details of the complex spatio-temporal evolution of alternating-sign osmotic strains at the initial stages of agent diffusion. Qualitatively different effects produced by particular hydrophilic OCAs, such as glycerol and iohexol, are discussed, as well as concentration-dependent differences. Overall, the work demonstrates the unique abilities of the new OCE-modality in providing a deeper insight in real-time kinetics of osmotically-induced strains relevant to a broad range of biomedical applications.

A numerical study of chloride migration in concrete under electrochemical repair

Electrochemical repair (ECR) is one of the most effective methods of removing chloride from offshore engineering structures to improve their durability. The diffusion of chloride and electrochemical migration are key stages in this process. In this work, a new numerical chloride migration–diffusion model was established using the Nernst–Planck equation. The distributions of free chloride ions in concrete in the stages of free chloride diffusion and ECR were simulated and the effects of the external potential and cathode position on ECR efficiency were analysed. The results showed that ECR can effectively remove chloride ions from concrete. After 12 weeks of ECR, the chloride removal efficiency was more than 66%. With an increase in the repair time, the ECR efficiency decreased gradually. In the initial stage of ECR, the chloride concentration on the rebar surface decreased rapidly. After 4 weeks of ECR, the chloride concentration tended to stabilise. The ECR efficiency also improved with an increase in external potential increases, with the chloride concentration on the reinforcing bar surface decreasing rapidly. When cathodes are set on both sides of the concrete, the ECR time should be extended and the external potential should be increased to achieve a better repair effect.

A simple embed over encryption scheme for DICOM images using Bülban Map.

With the onset of any pandemic, the medical image database is bound to increase. These medical images are prone to attack by hackers for their medical data and patient health information. To safeguard these medical images, a new algorithm is proposed. The algorithm involves secretly embedding the patient identification number into the medical image and encrypting the medical image, protecting the patient’s identity and the patient’s medical condition from hackers. The encryption algorithm involved a single stage of confusion and two stages of diffusion. The confusion operation was performed using the key generated by the Bülban map. The first stage of diffusion was done in the transform domain, using 5/3 transformation. The second diffusion stage was performed in the spatial domain by altering the pixel values using the key. The algorithm was tested on over 30 DICOM (Digital Imaging and Communications in Medicine) images taken from Open Science Framework (OSF), a public database for COVID-19 patients. The algorithm could resist the statistical attacks upon analysis, providing a PSNR of 7.084 dB and entropy of 15.9815 bits for the cipher image. The correlation coefficients for the cipher image were 0.0275, -0.0027, 0.018 in horizontal, vertical and diagonal directions. The keyspace was 2((M−1) ×N)×16, with M the number of rows and N the number of columns in the image. The key sensitivity was high. The test results and metric analysis prove that the algorithm is an effective one for embedding and encryption.Graphical abstract

Insight into the influence of morphology and structure of Fe3O4 nanoparticles on demulsification efficiencies

Functional Fe3O4 nanoparticle (Fe3O4 NP) is one of the most attractive candidates in the demulsification field because of its outstanding recycling ability, low cytotoxicity, and good biocompatibility. However, the lack of research on their interfacial properties greatly inhibits further development in the industrial demulsification process. The main aim of this work is to explore interfacial properties of functional Fe3O4 NPs from their intrinsic natures, namely morphologies and structures. Three Fe3O4 NPs with different morphologies, including triangle-shaped Fe3O4 NPs (TF NPs), octahedron-shaped Fe3O4 NPs (OF NPs) and truncated octahedron-shaped Fe3O4 NPs (TOF NPs), were prepared by using the solvothermal reaction. Their demulsification capacities of water-in-cyclohexane (W/C) emulsion were evaluated and the TOF NPs had best performance. The demulsification process including diffusion, adsorption and phase separation stages of these Fe3O4 NPs were investigated in detail by interfacial experiments and mathematical models for explain the demulsification result. The diffusion coefficient was calculated at both the early and late stages of the demulsification process, along with their adsorption energy and the elastic modulus of oil-water interfaces. TOF NPs had the largest diffusion coefficient of 1.777 × 10−6 and 2.443 × 10−6 m2/s at the early and late stages, respectively. The W/C interface adsorption energy of TOF NPs were much lower than that of the others and the elastic modulus of W/C interface reduced by TOF NPs was also more effective than that by the others.

Multi-view learning with distinguishable feature fusion for rumor detection

Researchers, enterprises, and governments have made great efforts to detect misinformation promptly and accurately. Traditional solutions either examine complicated hand-crafted features or rely heavily on the constructed credibility networks to extract useful indicators for discerning false information. However, such approaches require insightful domain expert knowledge and intensive feature engineering that are often non-generalizable. Recent advances in deep learning techniques have spurred learning high-level representations from textual and image content and discovering diffusion patterns with various neural networks. Despite the progress made by these methods, they still face the problem of overdependence on the content features and fail to discriminate against the influence of each user involved in the process of rumor spreading. Different user-aspect information plays different roles in various stages of rumor diffusion, effectively extract features from each aspect, and aggregate the learned features into a unique representation, which has not been well investigated. To address these limitations, we propose a novel model, UMLARD (User-aspect Multi-view Learning with Attention for Rumor Detection), to effectively learn the representation of different views of the users who engaged in spreading the tweet, and fuse the learned features through the distinguishable fusion mechanism. Finally, we concatenate the learned user-aspect features with content features to form a unique representation and feed it into a fully connected layer to predict the label of rumors. Our experiments conducted on real-world datasets demonstrate that UMLARD significantly improves the rumor detection performance compared to state-of-the-art baselines. It also allows explainability of the model behavior and the predicted results.

Two-stage model of prepreg bonding interface formation in automated fiber placement process

While Automated Fiber Placement (AFP) of thermoset matrix composites are widely used in the aviation industry, there is little conclusive research on the relationship between the physical model of bonding interface formation process and the actual bonding strength between prepreg layers formed in AFP process. Although massive amounts of experimental data on prepreg tack have been achieved from existing research, engineers are unable to use these data as a decisive criterion in choosing process parameters. In this research, a prepreg layup physical model based on reptation model and viscoelastic mechanical model is built, in which the bonding interface formation process is divided into two stages, namely, diffusion and viscous stage. Layup-peeling experiments are conducted via a special designed high-speed layup experimental platform so that practical AFP process parameters can be imitated, and a logarithmic curve of layup velocity-peeling energy under different layup pressure is achieved. The slope of the logarithmic curve and the surface morphology of the sample after peeling prove the correctness of the established model. Simultaneously, the experimental data proves that when prepreg is peeled off, the transition from the cohesive failure mode to the interface failure mode occurs at the laying speed between 100 mm/s and 200 mm/s. These results can be used as a reference for choosing AFP process parameters to realize the balance between good bonding quality and harmless separation of adjacent prepreg layers.

Tracing the evolution of service robotics: Insights from a topic modeling approach

Taking robotic patents between 1977 and 2017 and building upon the topic modeling technique, we extract their latent topics, analyze how important these topics are over time, and how they are related to each other looking at how often they are recombined in the same patents. This allows us to differentiate between more and less important technological trends in robotics based on their stage of diffusion and position in the space of knowledge represented by a topic graph, where some topics appear isolated while others are highly interconnected. Furthermore, utilizing external reference texts that characterize service robots from a technical perspective, we propose and apply a novel approach to match the constructed topics to service robotics. The matching procedure is based on frequency and exclusivity of words overlapping between the patents and the reference texts. We identify around 20 topics belonging to service robotics. Our results corroborate earlier findings, but also provide novel insights on the content and stage of development of application areas in service robotics. With this study we contribute to a better understanding of the highly dynamic field of robotics as well as to new practices of utilizing the topic modeling approach, matching the resulting topics to external classifications and applying to them metrics from graph theory.