Structure Of Matrix Research Articles

On a method of constructing a biaxial multitype conservative chaotic system and an image encryption scheme

On the basis of single axis coupling for constructing conservative chaos, a method for constructing a biaxial multitype conservative chaotic system is proposed. The method constructs more types of chaotic systems with a wider range of traversal. When coupling the Eulerian subbody biaxially, it is discovered that the structural matrix is able to exhibit two different multistates, namely, 0 and the opposite state, 0 and the same state, and depending on the location of the introduced adjustable parameter, the constructed chaotic equations also exhibit multiple types. When the structure matrix exhibits 0 and opposite state, the chaotic equations exhibit three types, which are opposite, one-parameter, and two-parameter types; and when the structure matrix is 0 and the same state, the chaotic equations exhibit the same type, one-parameter, and two-parameter types. The relationship of each pair of adjustable parameters satisfies the structure matrix antisymmetry, which leads to many types of Hamiltonian conservative chaotic systems that can transition between quasi-periodic, hyperchaotic, and chaotic states, all of which pass the NIST test, increasing the diversity of chaotic system choices in image encryption. The chaotic system is applied in image encryption, using Hadamard product matrix permutation, index permutation and four-dimensional pixel diffusion algorithms, and finally generates the ciphertext image. The method of biaxial coupling can construct six different types of chaotic systems, after image encryption, the average value of information entropy reaches 7.9994, the correlation coefficient is close to 0, the NPCR and UACI are close to the ideal values of 99.61 % and 33.46 %, the algorithm can effectively resist the statistical attack, the robustness attack and the differential attack, and the results demonstrate that the algorithm has better security performance.

Optical microscopy of ceramic materials based on fly ash from thermal power plants

The data on the annual release of ash and slag waste as a result of the operation of thermal power plants (TPP) in Siberia and the Far East of the Russian Federation are presented. The main reasons for the insignificant use of ash in the construction industry (about 5-8% of the total waste output) and the problems hindering its use for the production of ceramic wall materials are considered. A brief description of the composition and properties of the raw materials used in this work for the manufacture of ceramic wall materials is given. The compositions of the developed fly ash-based charges and the method of manufacturing ceramic samples with a matrix structure are given. The results of the study of the structure of ceramic materials by optical microscopy are presented. It is established that during the firing process, a matrix (dispersion medium) is formed from the fusible shell of aggregated complexes, and granules from fly ash are transformed into cores (dispersed phase) of a ceramic matrix composite. It was revealed that the kernels have an oval shape due to the deformation of the granules during pressing. Clusters are formed in the nuclei, consisting of a large number of small crystalline grains connected by an amorphous substance and edged with thin chains of pores. It is shown that the developed pore space inside the cores is mainly represented by frost-proof and reserve pores, which ensures high frost resistance of ceramic samples based on fly ash.

Pinning Asymptotic Observability of Distributed Boolean Networks.

Asymptotic observability of distributed Boolean networks (DBNs) is studied in this article. Via a parallel extension method, asymptotic observability of the original system is converted to reachability at a fixed point of the extended system. Based on the structure matrix of the extended system, a necessary and sufficient condition is presented for asymptotic observability. Further, for unobservable systems, mode-dependent pinning control is first introduced and applied to achieve asymptotic observability, including the selections of pinning nodes, the design of output feedback controls, and the adding approaches. Then, a set of matrices is defined for the construction of the desired structure matrix. Based on it, a necessary condition is given to guarantee the solvability of the corresponding output feedback controls and the adding approaches. Finally, a numerical example is presented to show the effectiveness of the obtained results.

Accelerated SVD-based initialization for nonnegative matrix factorization

Nonnegative matrix factorization (NMF) is a popular dimensionality reduction technique. NMF is typically cast as a non-convex optimization problem solved via standard iterative schemes, such as coordinate descent methods. Hence the choice of the initialization for the variables is crucial as it will influence the factorization quality and the convergence speed. Different strategies have been proposed in the literature, the most popular ones rely on singular value decomposition (SVD). In particular, Atif et al. (Pattern Recognit Lett 122:53–59, 2019) have introduced a very efficient SVD-based initialization, namely NNSVD-LRC, that overcomes the drawbacks of previous methods, namely, it guarantees that (i) the error decreases as the factorization rank increases, (ii) the initial factors are sparse, and (iii) the computational cost is low. In this paper, we improve upon NNSVD-LRC by using the low-rank structure of the residual matrix; this allows us to obtain NMF initializations with similar quality to NNSVD-LRC (in terms of error and sparsity) while reducing the computational load. We evaluate our proposed solution over other NMF initializations on several real dense and sparse datasets.

Spinning-additive hybrid manufacturing of Al-Zn-Mg-Cu alloys: Microstructure evaluation and mechanical properties

This study employs wire-arc direct energy deposition (wire-arc DED) to produce high-strength aluminum alloys on the spinning matrix. Spinning-additive hybrid manufacturing specimens were produced. The evolution mechanism of the interfacial microstructure and fracture behavior of the hybrid manufacturing (HM) specimens was analyzed. The results indicate that the microstructure morphology can be divided into three regions: the spinning zone (SZ), columnar grain (CG) zone of additive manufacturing (AM), and equiaxed grain (EG) zone of AM. The SZ exhibits a bimodal grain structure, while the AM-CG zone consists of epitaxial growth from the SZ, and the AM-EG zone comprises equiaxed grains. Due to the influence of the hot spinning process, a large amount of eutectic structure and η phase coexist in the spinning matrix, resulted in a small amount of undissolved η phase remaining in the spinning matrix after heat treatment. A small amount of η' phase was generated in the AM zone at as-deposited state, due to the effect of in situ thermal cycling of the subsequent additive manufacturing process. Nearly all of η phase which dissolves into the α-Al matrix after heat treatment. The tensile strength of the hybrid manufactured samples increased from 256 MPa in the as-deposited state to 528 MPa after heat treatment. The fine-grained region of the spinning matrix experiences deformation and crack propagation initially, attributed to the softer properties of the fine-grained region within the bimodal grain structure of the SZ matrix, ultimately resulting in fracture at the SZ in all hybrid manufactured specimens.

Effect of double quenching process on Microstructure and Properties of 20CrMoH Alloy Steel

Abstract This article investigates the influence of dual quenching process quenching temperature on the microstructure, hardness, and mechanical properties of 20CrMoH alloy steel through optical metallographic microscopy, Rockwell hardness tester, and universal mechanical testing machine. The results indicate that during the second quenching in the temperature range of 780-880 °C, with the increase of quenching temperature, the tensile strength of 20CrMoH steel shows a rapid increase trend, from 1250MPa to 1550MPa. At this time, the matrix structure gradually evolves from ferrite + bainite structure to bainite + martensite, which is also the main factor for its rapid increase in tensile strength; When the quenching temperature rises to above 850 °C, the influence of quenching temperature on the tensile strength decreases, and the tensile strength remains around 1550MPa. The secondary quenching temperature has little effect on the plasticity of the material. The overall reduction and elongation of the section under different quenching temperature conditions are at a similar level, with a reduction rate of 9% -12% and a stable reduction rate of 50% -60%, indicating good mechanical properties.

Extended Second-Order Moment Symmetry Model and Decomposition of Symmetry Model for Ordinal Square Contingency Tables

This study proposes the extended second-order moment symmetry model in square contingency tables with same row and column ordinal classifications. The proposed model extends the previous second-order moment symmetry model by incorporating an asymmetry parameter to capture complex structures. The proposed and previous second-order moment symmetry models represent the asymmetry and symmetry structure of the covariance matrix, respectively. The previous study showed the decomposition of the symmetry model using the second-order moment symmetry model. This study shows the decomposition of the second-order moment symmetry model using the proposed model and the decomposition of the symmetry model applying its decomposition. The usefulness of proposed model is illustrated with examples of two real world datasets (cross-classified education of parents and cross-classified social group of fathers and their daughters).

Energy conservation strategies on academic buildings using interpretive structural modeling to develop energy sustainability

Effective energy conservation strategies are required to be implemented in academic buildings as they consume significant energy while considering the convenience and function of the buildings. However, the influencing factors are interrelated and complex, requiring an appropriate approach to unravel the complexity. Therefore, this study aims to identify, analyse, and map the interaction relationship between factors affecting energy conservation in academic buildings. This study used Interpretive Structural Modeling (ISM) procedure starting from developing the Structural Self Interaction Matrix (SSIM), converting SSIM into a Reachability Matrix, revising the matrix, and categorizing the factors by using MICMAC analysis. This study involved 9 factors, including architectural design, illumination technology, education and awareness, energy monitoring and management, renewable energy use, efficient HVAC system, energy-saving equipment, institutional policies, and campus community participation. The study found that renewable energy use at level 3 was the factor that was not influenced by and did not interact with any other factors. Meanwhile, the illumination technology was a factor that interacted with the efficient HVAC System factor which was at level 1 where these two factors were influenced by other seven factors. This study aligns with current developments in energy conservation, including an increased focus on renewable energy and energy efficiency in academic buildings, supported by global and national policies aimed at achieving sustainability goals. It provides a comprehensive understanding on developing sustainable energy conservation strategies in academic buildings.

Influence of disperse-hardening additive chrome diboride on the structure of carbide matrixes of PDC drill bits

Influence of disperse-hardening additive chrome diboride on the structure of carbide matrixes of PDC drill bits

The insights of allied health professionals transitioning from a matrix structure to a centralized profession-based structure within a public hospital setting

The insights of allied health professionals transitioning from a matrix structure to a centralized profession-based structure within a public hospital setting

Microstructure and high-temperature properties of SiCNWs/Ti60 composites fabricated by rapid sintering of SPS

Improving the high-temperature performance of titanium alloys or titanium matrix composites is crucial for applications in various high-temperature fields. In this study, rapid sintering using Spark plasma sintering (SPS) is employed to fabricate SiCNWs-reinforced Ti60 composites to mitigate the chemical reaction between the materials. The sintered SiCNWs/Ti60 composites exhibit a lamellar and equiaxial matrix structure with SiCNWs distributed in boundary areas of original Ti60 powders. 0.50SiCNWs/Ti60 demonstrates the best comprehensive tensile properties, achieving ultimate tensile strengths (UTS) of 734.4 MPa, 585.9 MPa, and 263.34 MPa at 600 °C, 700 °C, and 800 °C, respectively. This represents an increase of 17.6 %, 25.8 %, and 20.5 % compared to pure Ti60. The improved strength can be primarily attributed to load-transfer effect of SiCNWs. Additionally, solid solution strengthening from C and Si elements, as well as fine grain strengthening, also contributed to the overall strengthening.

Electrochemical and photoluminescence properties of Ce3+ doped copper aluminate nanoparticles

In this communication, for the first of its kind, CuAl2O4 doped with Ce3+ (1-9 mol %) are syn- thesized by solution combustion method using Aloe Vera gel as a reducing agent. The as-formed sample was calcined at 500° C for 3 hours, followed by characterization. The addition of dopants to the copper aluminate matrix didn't alter the crystal structure of the host matrix. Bragg reflec- tions confirm the formation of the cubic phase and also absence of other impurities. The surface morphology consists of nanorods arranged one above the other. The estimated crystallite size was found to decrease from 12 to 9 nm whereas, the direct energy band gap increases from 2.84 to 3.02 eV with an increase in dopant concentration. Under λex = 305 nm excitation, photoluminescence (PL) emission spectra have a high intense peak at 553 nm along with a less intense peak at 472 nm. The peak at 553 nm can be attributed to the existence of oxygen vacancies which arise due to the transition of an electron from the 2D3/2→2F7/2 of Ce3+, however, the peak observed at 472 nm results from the transition of ionized oxygen vacancies (VO) to the valence band caused by the 2D3/2→2F5/2 transition. The CIE coordinates lie well within the green region with 5758 K aver- age CCT. Further, Cyclic voltammetry analysis was conducted to investigate oxidation and redox peaks, while electrochemical impedance spectroscopy provided insights into ion transport kinetics. Specific capacitance values ranging from 29 to 59 F/g were obtained for CuAl2O4:Ce(1-9 mol %) NPs. These findings suggest potential applications for the synthesized material in areas such as display technology as a green nano phosphor and energy storage materials.

Effect of heat treatment on electromagnetic shielding performance of electroless copper-nickel on wood

The wood-based composites have received extensive attention in the field of electromagnetic interference (EMI) due to inherent layered porous structure. In this study, the deposition Ni and Cu-Ni on wood surface and heat treatment temperature were used as variables. The variation law of electromagnetic shielding (EMS) performance of composite materials is analyzed. The results showed that Ni particles were fully filled in the layered porous structure of the wood, and the metal coatings evenly covered the entire wood surface. The Ni content of the wood based composite materials via 260 °C heat treatment was up to 98.04 %. The pore structure was more regular with the increase of the number of deposition Ni. The ideal roughness was 11.33 μm and the conductivity reached a maximum of 46.8 S/cm at 200 °C. The EMS effectiveness of one deposition Ni composite materials showed an increasing trend when the heat treatment was 200 ℃, 220 ℃, 240 ℃, 260 ℃ and 280 ℃, respectively. When the heat treatment temperature is 260 °C, the EMS effectiveness of the wood-based composite material can reach 88.76 dB, and the hydrophobicity can reach 99.55 °. When the temperature is 300 °C, the electromagnetic shielding effectiveness can reach 91 dB, and the hydrophobicity can reach 117 °. The anisotropic internal porous structure of wood matrix and the multi-interface polarization between wood and Cu-Ni are the main reasons for the high EMS performance.

Bracing systems for three-ribbed arch bridges against out-of-plane buckling

This paper is concerned with the design of bracing systems for three-ribbed parabolic arch bridges against out-of-plane buckling. Typical bracing systems for the three-ribbed arch bridges include K-bracing system and X-bracing system as well as transverse bracing system. The buckling criterion of the braced funicular three-ribbed arch bridge is derived from an exact matrix stiffness method (MSM) with a 14 × 14 s-order element stiffness matrix of three-dimensional beam-column elements that allows for torsional and warping deformations. The lateral torsional buckling load and mode are given by the lowest eigenvalue and eigenvector associated with the assembled structural stability stiffness matrix. A comparison study between different bracing system configurations suggests that the three-ribbed arches with the integral K- or X-bracing system (a K/X-bracing across the three arch ribs) have lower lateral torsional buckling loads than their arch counterparts with the independent K- or X-bracing system (the adjacent arch ribs are connected by K/X-bracing respectively), because the latter ones could provide more restraint on the middle arch rib to avoid early lateral torsional instability. Further, a bracing utilization efficiency index (defined as the normalized buckling capacity over material usage for bracing system) is proposed to quantify the effect of bracing systems in improving the lateral torsional buckling capacity of arch bridges. Highly efficient bracing systems that maximize the lateral torsional buckling load of three-ribbed arch structures with the lowest bracing material usage are then recommended.

Study on the Effect of Silica–Manganese Slag Mixing on the Deterioration Resistance of Concrete under the Action of Salt Freezing

The use of silico-manganese slag as a substitute for cement in the preparation of concrete will not only reduce pollution in the atmosphere and on land due to solid waste but also reduce the cost of concrete. To explore this possibility, silico-manganese slag concrete was prepared by using silico-manganese slag as an auxiliary cementitious material instead of ordinary silicate cement. The mechanical properties of the silico-manganese slag concrete were investigated by means of slump and cubic compressive strength tests. The rates of mass loss and strength loss of silico-manganese slag concrete were tested after 25, 50, and 75 cycles. The effect of the silica–manganese slag admixture on the microfine structure and properties of concrete was also investigated using scanning electron microscopy (SEM). Finally, the damage to the silica–manganese slag concrete after numerous salt freezing cycles was predicted using the Weibull model. The maximum enhancement of slump and compressive strength by silica–manganese slag was 17.64% and 11.85%, respectively. The minimum loss of compressive strength after 75 cycles was 9.954%, which was 34.96% lower than that of the basic group. An analysis of the data showed that the optimal substitution rate of silica–manganese slag is 10%. It was observed by means of electron microscope scanning that the matrix structure was denser and had less connected pores and that the most complete hydration reaction occurred with a 10% replacement of silica–manganese slag, where an increase in the number of bladed tobermorite and flocculated C-S-H gels was observed to form a three-dimensional reticulated skeleton structure. We decided to use strength damage as a variable, and the two-parameter Weibull theory was chosen to model the damage. The final comparison of the fitted data with the measured data revealed that the model has a good fitting effect, with a fitting parameter above 0.916. This model can be applied in real-world projects and provides a favorable basis for the study of damage to silica–manganese slag concrete under the action of salt freezing.

Development of Phase-Separating Microfiber Network Hydrogels to Promote In Vitro Vascularization.

Engineered vascularized tissues in vitro exhibit the potential for transplantation therapy and disease modeling. Despite efforts to design hydrogels as cell culture platforms for in vitro vascularization, development of vascularized tissues recapitulating the natural structures and functions remains difficult due to a poor understanding of the relationships between the matrix microstructures and tube formation of endothelial cells. Herein, we developed microfiber network hydrogels with microporous structures by controlling the liquid-liquid phase separation (LLPS) of proteins and matrix structures in hydrogels. Extracellular matrix protein gelatin was modified with hydrogen-bonding moieties and mixed with hyaluronic acid sodium salt to form microfiber network structures. Gelatin gelation and hyaluronic acid sodium salt dissolution led to the formation of a microporous microfiber network hydrogel formation. Matrix structures of hydrogels were modified by controlling LLPS that affects endothelial cell tube formation. Vascularization was improved using laminin peptides and coculturing with mesenchymal stem cells. Overall, our approach exhibits the potential to induce in vitro vascularization for regenerative medicine and disease modeling applications.

Converting ocean nacre into bone mineral matrix composite for bone regeneration- in vitro and in vivo studies

Nacre of Pinctada maxima is a natural biomineralized matrix, appeared 7 million years before hominins. In this study, we converted nacre into a self-setting particle bound with multiple calcium orthophosphates that reassemble mammals’ bone mineral matrices for induction of bone regeneration. The nacre-based calcium orthophosphates composite (NCOC) exhibited a compression strength of 10 MPa, which is superior to human trabecular bone. In vitro bioactivity tests revealed the formation of apatite with nano-porous flake-like crystals on the composite surface that mimic HA structure of a human bone matrix. NCOC demonstrated efficient attachment and proliferation of osteoblast cells, promoting osteogenic differentiation by increasing expressions of RUNX2 and OPN. In vivo studies using rabbit back fascia demonstrated that NCOC displays better bone healing and biocompatibility than conventional bone substitute apatite in critical bone defect models. The degradation of calcium carbonate crystal in vivo does not compromise structural integrity of NCOC. Overall, our data showed that NCOC produced through self-setting reactions, presents advantages such as accelerated biodegradation and osteostimulative properties, making it a promising bone substitute for effective bone regeneration.

A CAD-oriented parallel-computing design framework for shape and topology optimization of arbitrary structures using parametric level set

Recently, the high-resolution topology optimization to promote engineering applicability has gained much more attentions. However, an accurate and highly-efficient design framework for implementing shape and topology optimization of engineering structures with integration of CAD model is still in demand. In the current work, the critical intention is to develop a CAD-oriented parallel-computing design framework for arbitrary structures, where the Parametric Level Set Method (PLSM) is employed for shape and topology optimization. Firstly, an implicit identification model is constructed for generating a signed distance field using the vertex and normal information from the ‘STL’ file of engineering structures. The signed distance field is combined with the compactly supported radial basis functions (CSRBFs) to solve the initial level set function with a parametrization. This method is applied to present all domains, including design domains, Neumann boundary domains, Dirichlet boundary domains, and non-design domains. Secondly, the CPU parallel strategy is considered for allocating partitions of structural stiffness matrix in finite element analysis to different CPU cores for the parallel-computing to save computation costs. Thirdly, a parallel-computing design formulation is developed for performing shape and topology optimization of arbitrary structures, in which the partitioned terms of all design variables and stiffness matrix are concurrently computed on each CPU core. Finally, several classic benchmarks and the critical engineering structure of Virtual Reality (VR) glass part with extremely complex geometries, are discussed to demonstrate the effectiveness and efficiency of the proposed design framework.

Thirdhand smoke exposure promotes gastric tumor development in mouse and human

The pollution of indoor environments and the consequent health risks associated with thirdhand smoke (THS) are increasingly recognized in recent years. However, the carcinogenic potential of THS and its underlying mechanisms have yet to be thoroughly explored. In this study, we examined the effects of short-term THS exposure on the development of gastric cancer (GC) in vitro and in vivo. In a mouse model of spontaneous GC, CC036, we observed a significant increase in gastric tumor incidence and a decrease in tumor-free survival upon THS exposure as compared to control. RNA sequencing of primary gastric epithelial cells derived from CC036 mice showed that THS exposure increased expression of genes related to the extracellular matrix and cytoskeletal protein structure. We then identified a THS exposure-induced 91-gene expression signature in CC036 and a homologous 84-gene signature in human GC patients that predicted the prognosis, with secreted phosphoprotein 1 (SPP1) and tribbles pseudokinase 3 (TRIB3) emerging as potential targets through which THS may promote gastric carcinogenesis. We also treated human GC cell lines in vitro with media containing various concentrations of THS, which, in some exposure dose range, significantly increased their proliferation, invasion, and migration. We showed that THS exposure could activate the epithelial-mesenchymal transition (EMT) pathway at the transcript and protein level. We conclude that short-term exposure to THS is associated with an increased risk of GC and that activation of the EMT program could be one potential mechanism. Increased understanding of the cancer risk associated with THS exposure will help identify new preventive and therapeutic strategies for tobacco-related disease as well as provide scientific evidence and rationale for policy decisions related to THS pollution control to protect vulnerable subpopulations such as children.

First-year health professions students’ interprofessional identity development following participation in a brief introductory interprofessional activity: a qualitative study

ABSTRACT Healthcare providers need to simultaneously identify with their own profession and the broader interprofessional group to improve interprofessional team functioning and collaboration. The purpose of this study was to explore firstyear healthcare students’ interprofessional identity development following a brief introductory interprofessional activity. The Extended Professional Identity Theory (EPIT) served as the framework for this qualitative study. The sample included 1,047 students from 19 different health professions at one institution in the first semester of their professional program. Deductive content analysis was used to analyze students’ reflections from two reflective questions in a mandatory course evaluation survey. The 24-item version of the Extended Professional Identity Scale was used as a structured categorization matrix for deductive coding of student reflections to the three EPIT constructs: interprofessional belonging, commitment, and beliefs. Participant responses, spanning all three EPIT constructs, support the ability of early health professions learners to demonstrate the development of an emerging interprofessional identity. Future research is needed to assess IPI at various points across the curriculum and to explore between profession differences and the implications for foundational IPE design and learning along the continuum into practice.