Structure Of Matrix Research Articles

On the structure of the matrix in Sturm algorithm for determining the number of zeros in the open unit disk for a real polynomial

In 1984, C.W Schelin presented a numerical method for calculating the number of zeros of a real polynomial inside the unit disk using the argument principle and Cauchy index on [-1, 1] inspired by sturm’s algorithm [3], this method is based on calculation of the generalized Sturm sequence in Chebyshev form, however in some cases this algorithm does not efficient for this reason, it has been modified in another works [1], [2]. There are other numerical algorithms for calculating the number of zeros of a polynomial in the unit disk like shur -Cohn and Marden-Cohn but the numerical method presented in this study [1] is more efficient in cost of elementary operations (o (n2)). In this paper, we propose to improve this algorithm [1], to do this we study the matrix structure involved in the calculation of chebychev polynomials, for there on we prove that is a Toeplitz matrix which is known for their important properties in the complexity of calculations and we calculate its last line which is necessary to define the whole matrix to solve the linear system for calculating polynomials which are necessary to obtain Chebyshev sequence, this result will reduce calculation steps in this method [1]. This numerical algorithm may operate to study the stability of dynamical systems [2].

Amplifying Fibre Optic Sensor Signals with Graphene Oxide-Silver Nanostars

This work presents a straightforward yet impactful method to enhance optical fibre sensor signals by integrating silver nanostars (AgNS) with graphene oxide (GO-AgNS) as a sensing material. AgNS were synthesized successfully via a one-step chemical reduction method using hydroxylamine as a reducing agent. The concentration of hydroxylamine was varied (7.2, 3.6, 1.8, and 0.9) x 10−4 %v/v to optimize AgNS formation, with the longest spike of the nanostar observed at lower hydroxylamine concentrations, as confirmed by transmission electron microscopy (TEM). UV-visible measurements revealed the highest peak absorption for AgNS synthesized using 0.9 x 10−4 %v/v hydroxylamine, 0.05 M sodium hydroxide, 0.8 mM silver nitrate, and 0.045 M sodium citrate, with an average length of 352.62 ± 59.72 nm measured from TEM images. GO was synthesized via a modified Hummer’s method and mixed with AgNS at varying ratios (1:5, 1:10, 1:15, and 1:20) to form GO-AgNS coatings for the fibre optic probe. The GO-AgNS coating at a ratio of 1:5 exhibited the highest light absorption intensity, enhancing optical signal by 218% compared to GO-coated and 174% compared to AgNS-coated fibre optic sensors. These findings demonstrate that embedding AgNS onto the GO matrix structure as a sensing material significantly improves sensor performance, suggesting promising applications for super-sensitive, cost-effective, and rapid detection in fibre optic-based sensors.

Three-dimensional breast cancer tumor models based on natural hydrogels: a review.

Breast cancer is the most common cancer in women and one of the deadliest cancers worldwide. According to the distribution of tumor tissue, breast cancer can be divided into invasive and non-invasive forms. The cancer cells in invasive breast cancer pass through the breast and through the immune system or systemic circulation to different parts of the body, forming metastatic breast cancer. Drug resistance and distant metastasis are the main causes of death from breast cancer. Research on breast cancer has attracted extensive attention from researchers. In vitro construction of tumor models by tissue engineering methods is a common tool for studying cancer mechanisms and anticancer drug screening. The tumor microenvironment consists of cancer cells and various types of stromal cells, including fibroblasts, endothelial cells, mesenchymal cells, and immune cells embedded in the extracellular matrix. The extracellular matrix contains fibrin proteins (such as types I, II, III, IV, VI, and X collagen and elastin) and glycoproteins (such as proteoglycan, laminin, and fibronectin), which are involved in cell signaling and binding of growth factors. The current traditional two-dimensional (2D) tumor models are limited by the growth environment and often cannot accurately reproduce the heterogeneity and complexity of tumor tissues in vivo. Therefore, in recent years, research on three-dimensional (3D) tumor models has gradually increased, especially 3D bioprinting models with high precision and repeatability. Compared with a 2D model, the 3D environment can better simulate the complex extracellular matrix components and structures in the tumor microenvironment. Three-dimensional models are often used as a bridge between 2D cellular level experiments and animal experiments. Acellular matrix, gelatin, sodium alginate, and other natural materials are widely used in the construction of tumor models because of their excellent biocompatibility and non-immune rejection. Here, we review various natural scaffold materials and construction methods involved in 3D tissue-engineered tumor models, as a reference for research in the field of breast cancer.

Comparative Analysis of Commercially Available Extracellular Matrix Soft Tissue Bioscaffolds.

Decellularized extracellular matrix (dECM) products are widely established for soft tissue repair, reconstruction and reinforcement. These regenerative biomaterials mimic native tissue ECM with respect to structure and biology and are produced from a range of tissue sources and species. Optimal source tissue processing requires a balance between removal of cellular material and the preservation of structural and biological properties of tissue ECM. Despite the wide-spread clinical use of dECM products there is a lack of comparative information on these products Structurally, some dECM products showed a well-preserved collagen architecture with a broad porosity distribution, while others showed a significantly altered structure compared with native tissue. Decellularization varied across the products. Some materials surveyed (OFMm, PPN, PPC, OFMo, UBM, SISz, ADM, PADM and BADM) were essentially devoid of nuclear bodies (mean count of <5 cells per high powered field (HPF)), whereas others (SISu and SISb) demonstrated an abundance of nuclear bodies (>50 cells per HPF). Pathology assessment of the products demonstrated that OFMm, OFMo and PADM had the highest qualitative assessment score for collagen fiber orientation and arrangement, matrix porosity, decellularization efficiency, and residual vascular channels scoring 10.5±0.8, 12.8±1.0, and 9.7±0.7 out of a maximum total score of 16, respectively This analysis of commercially available dECM products in terms of their structure and cellularity includes 12 different commercial materials The findings highlight the variability of the products in terms of matrix structure and the efficacy of decellularization.

PLA/CB and HDPE/CB conductive polymer composites: Effect of polymer matrix structure on the rheological and electrical percolation threshold

AbstractIn this study, the effect of the polymer matrix structure on the rheological and electrical percolation threshold of polymer/carbon black (CB) conductive polymer composites (CPCs) was investigated. Poly(lactic acid) (PLA) and high‐density polyethylene (HDPE) were used as polymer matrices. Through rheological analyses, an increase in complex viscosity was observed with increasing CB concentration, accompanied by a reduction in the Newtonian plateau. Additionally, an increase in the solid‐like behavior was observed, suggesting the formation of a percolated network. The rheological percolation threshold was found to be 5.13% CB mass fraction for the PLA/CB composite and 10.72% for the HDPE/CB composite. Electrical conductivity results were fitted to the sigmoidal Boltzmann model, and its derivative was used to identify the electrical percolation threshold. For PLA/CB, this threshold was reached at 5.39% CB mass fraction, while for HDPE/CB, it occurred at 5.75%. Morphology analysis by scanning electron microscopy and atomic force microscopy indicated that the polymer matrix structure affected the distribution/dispersion of the CB particles within the polymer matrix.Highlights The effect of polymer matrix structure on polymer/CB CPCs was investigated. The crystallinity of the polymer matrix affected the percolation threshold. PLA/CB showed higher conductivity than HDPE/CB CPCs.

SEMbap: Bow-free covariance search and data de-correlation.

Large-scale studies of gene expression are commonly influenced by biological and technical sources of expression variation, including batch effects, sample characteristics, and environmental impacts. Learning the causal relationships between observable variables may be challenging in the presence of unobserved confounders. Furthermore, many high-dimensional regression techniques may perform worse. In fact, controlling for unobserved confounding variables is essential, and many deconfounding methods have been suggested for application in a variety of situations. The main contribution of this article is the development of a two-stage deconfounding procedure based on Bow-free Acyclic Paths (BAP) search developed into the framework of Structural Equation Models (SEM), called SEMbap(). In the first stage, an exhaustive search of missing edges with significant covariance is performed via Shipley d-separation tests; then, in the second stage, a Constrained Gaussian Graphical Model (CGGM) is fitted or a low dimensional representation of bow-free edges structure is obtained via Graph Laplacian Principal Component Analysis (gLPCA). We compare four popular deconfounding methods to BAP search approach with applications on simulated and observed expression data. In the former, different structures of the hidden covariance matrix have been replicated. Compared to existing methods, BAP search algorithm is able to correctly identify hidden confounding whilst controlling false positive rate and achieving good fitting and perturbation metrics.

Evaluation of Shear-Punched Surface Layer Damage in Ultrahigh-Strength TRIP-Aided Steels with Bainitic Ferrite and/or Martensite Matrix Structure

Evaluation of Shear-Punched Surface Layer Damage in Ultrahigh-Strength TRIP-Aided Steels with Bainitic Ferrite and/or Martensite Matrix Structure

Microwave-assisted in-situ synthesis of low-dimensional perovskites within metal-organic frameworks for optoelectronic applications

Halide perovskites are renowned for their remarkable optoelectronic properties, yet their application is hindered by stability challenges. Metal-organic frameworks (MOFs) have emerged as promising matrices for enhancing perovskite durability. In this study, we achieved the in-situ synthesis of a series of perovskites within the MOF-5 matrix, spanning three-dimensional, quasi two-dimensional, and two-dimensional structures, via microwave-assisted reaction techniques. This microwave synthesis method has proven to be a rapid and efficient approach for the high-yield production of perovskite materials. These MOF-5⊃perovskites exhibited superior optical properties, positioning them as promising candidates for various optoelectronic applications, including white light-emitting diodes and optical wireless communication (OWC) systems. Significantly, our perovskites demonstrated high and consistent communication rates, making them suitable for both space and underwater OWC deployments. Overall, our study underscores the potential of microwave-assisted synthesis in advancing high-performance perovskite materials, offering valuable insights for the development of future optoelectronic devices.

High-Performance Polyamidoxime Porous Membrane Prepared by the In Situ Modification/Nonsolvent-Induced Phase Separation Strategy for Uranium Extraction from Seawater.

The abundance of uranium (U(VI)) reserves in seawater makes it crucial to develop economically efficient methods for uranium extraction from seawater. In this work, an enhanced polyamidoxime porous membrane (PAOM) was fabricated by pre-in situ amidoxime modification combined with nonsolvent-induced phase separation (NIPS). The strategy of in situ modification of the polyacrylonitrile (PAN) solution served to enhance the homogeneity of the reaction and avoid the destruction of the membrane matrix and pore structure. Compared with the control sample (AOPM), PAOM possessed better mechanical strength and hydrophilicity. The introduction of polyvinylpyrrolidone (PVP) formed a porous structure in PAOM, improving spatial accessibility and facilitating the diffusion transport and capture of UO22+ inside the membrane. The more uniform and abundant distribution of amidoxime groups in PAOM gave it ultrahigh adsorption capacity and selectivity. The equilibrium adsorption capacity and Kd value of PAOM were 1.72 and 5.51 times higher than those of AOPM. Meanwhile, PAOM also demonstrated good recyclability, with only a 6.15% decrease in adsorption capacity after seven cycles. Additionally, PAOM exhibited excellent dynamic adsorption performance, and after 14 days of continuous filtration and adsorption, PAOM could extract 2.03 mg·g-1 U(VI) from natural seawater.

In-situ high-temperature EBSD study of austenite reversion from martensite, bainite and pearlite in a high-strength steel

The austenite (γ) reversely transformed from lath martensite (LM), lath bainite (LB), granular bainite (GB) and pearlite+ferrite (P+F) in a high-strength steel was studied at high temperatures using in-situ electron backscatter diffraction (EBSD). The memory effect of initial γ significantly affects the nucleation of the reverted γ in LM and GB structures, while a weak influence on that of LB and P+F structures. This results in a significant difference in γ grain size after complete austenitization, with the first two obtaining larger γ grains while the latter two are relatively small. Crystallographic analysis revealed that the reverted γ with acicular morphology (γA), most of which maintained the same orientation with the prior γ, dominated the reaustenitization behavior of LM and GB structures through preferential nucleation within γ grains and coalesced growth modes. Although globular reverted γ (γG) with random orientation or large deviation from the prior γ can nucleate at the grain boundaries or within the grains, it is difficult for it to grow and play a role in segmenting and refining the prior γ due to the inhibition of γA coalescing. For LB and P+F structures, the nucleation rate of intragranular γG increases with increasing temperature, and always shows a random orientation. These γG grains can coarsen simultaneously with the intergranular γG, ultimately playing a role in jointly dividing and refining the final γ grains. Research also found that the differences in the effects of four different microstructures on reverted γ nucleation are closely related to the variant selection of the matrix structure, as well as the content and size of cementite (θ). High density of block boundaries induced by weakening of variant selection and many fine θ formed in the lath are the key to promoting LB structure to obtain more intragranular γG formation, as well as the important role of the large-sized θ in P+F structure.

Physicochemical characterization and potential cancer therapy applications of hydrogel beads loaded with doxorubicin and GaOOH nanoparticles

A new type of hybrid polymer particles capable of carrying the cytostatic drug doxorubicin and labeled with a gallium compound was prepared. These microparticles consist of a core and a hydrogel shell, which serves as the structural matrix. The shell can be employed to immobilize gallium oxide hydroxide (GaOOH) nanoparticles and the drug, resulting in hybrid beads with sizes of approximately 3.81 ± 0.09 μm. The microparticles exhibit the ability to incorporate a remarkably large amount of doxorubicin, approximately 0.96 mg per 1 mg of the polymeric carrier. Additionally, GaOOH nanoparticles can be deposited within the hydrogel layer at an amount of 0.64 mg per 1 mg of the carrier. These nanoparticles, resembling rice grains with an average size of 593 nm by 155 nm, are located on the surface of the polymer carrier. In vitro studies on breast and colon cancer cell lines revealed a pronounced cytotoxic effect of the hybrid polymer particles loaded with doxorubicin, indicating their potential for cancer therapies. Furthermore, investigations on doping the hybrid particles with the Ga-68 radioisotope demonstrated their potential application in positron emission tomography (PET) imaging. The proposed structures present a promising theranostic platform, where particles could be employed in anticancer therapies while monitoring their accumulation in the body using PET.

Auto-DSM: Using a Large Language Model to generate a Design Structure Matrix

The Design Structure Matrix (DSM) is an established method used in dependency modelling, especially in the design of complex engineering systems. The generation of DSM is traditionally carried out through manual means and can involve interviewing experts to elicit critical system elements and the relationships between them. Such manual approaches can be time-consuming and costly. This paper presents a workflow that uses a Large Language Model (LLM) to support the generation of DSM and improve productivity. A prototype of the workflow was developed in this work and applied on a diesel engine DSM published previously. It was found that the prototype could reproduce 357 out of 462 DSM entries published (i.e. 77.3%), suggesting that the work can aid DSM generation. A no-code version of the prototype is made available online to support future research.

Application of information technology in transportation operation: A benchmarking approach by ISM MICMAC analysis

This study compares the obstacles to the efficient integration of Information Technology into Transportation services. In order to comprehend the significance and connections between the identifying criteria, a hybrid Interpretive Structural Modelling (ISM) and Matrix Impact Cross Multiplication Applied to Classification (MICMAC) analysis was performed. Based on the experts’ opinion, Government factors, financial restrictions, sector restrictions, firm-related restrictions, and a shift in demand are the five factors that emerged. According to the ISM-based study model, the Information Technology - enabled applications in Transportation services operations is driven by governmental restrictions, then financial constraints, construction industry constraints, and firm-related constraints.

Fluorine Doping Modulating Pore Structure and Adsorption Capability of Carbon Matrix Boosting Potassium Storage Performance of Red Phosphorus Anode

AbstractThe application of alloying‐typed red phosphorus (red P) anode in potassium‐ion batteries (KIBs) with ultra‐high theoretical capacity is hindered by the limited capacity and fast capacity decay due to poor electronic conductivity and huge volume change. Herein, a facile and efficient strategy of fluorine (F) doping is innovatively developed to modulate the pore structure of carbon matrix (F‐CNS) to encapsulate red P with enhanced potassium storage capability. Theoretical calculations reveal that F doping induces additional defects within the carbon layer, which facilitates P4 molecules embedding into the F‐doping‐induced micropores, enhances the adsorption ability toward K atoms and P4 molecules, and improves electrochemical kinetics assisted with more charge transfer obtained from the electron density difference, thus enabling robust potassium storage capability for such unique Red P@F‐CNS anode. Accordingly, the Red P@F‐CNS anode demonstrates outstanding cycling stability (90% capacity retention after 800 cycles at 2A g−1), and the potassium‐ion full cell (Red P@F‐CNS//KFeHCF) exhibits exceptional long‐term cycling performance (129 mAh g−1 after 2500 cycles at 5 A g−1 with only 0.014% decay per cycle). In situ characterizations confirm the superior structural integrity of the carbon‐based matrix. This study offers a rational design principle for engineering high‐performance carbon‐supported alloying‐typed anodes for KIBs.

Synthesis and Characterization of Novel Hybrid Wollastonite-Metakaolin-Based Geopolymers.

Over the past few decades, researchers have focused on developing new production methods for geopolymers to improve their properties for use in multiple applications as a functional material. This study introduces a new geopolymer system based on wollastonite and metakaolin as precursors. The role of wollastonite was also explored alongside metakaolin in geopolymers. Geopolymers were synthesized by adding wollastonite to metakaolin in different ratios: 0 wt.%, 12.5 wt.%, 25 wt.%, and 50 wt.%. The alkaline activator was then mixed with the powder, wollastonite, and metakaolin to prepare the geopolymers. In addition to mechanical tests, the hardened geopolymers were characterized using XRD, TGA, and SEM techniques. The findings revealed that adding wollastonite in amounts of 0 wt.%-12.5 wt.% did not affect the strength of the geopolymers. Increasing wollastonite between 25 wt.% and 50 wt.% significantly increased the geopolymers' flexural and compressive strength from 3 MPa to 12.3 MPa and from 23 MPa to 54 MPa, respectively. The use of wollastonite as a precursor also led to fundamental changes in the microstructural structure of the geopolymer matrix: a new crystal phase, (Ca5(SiO4)2(OH)2), calciochondrodite was formed, and the Si-Al-Na crystal phase disappeared, leading to significant changes in the amorphous phase.

Green and renewable thermoplastic polyvinyl alcohol/starch blend film fabricated by melt processing

In this study, the PVA/starch blend films were prepared by dry melting method. The microstructure showed that the starch existed in the continuous PVA matrix in granular structure. When the amount of starch was 30 wt%, the tensile strength increased from 12.8 to 14.7 MPa, and the elastic modulus increased from 15.4 to 20.5 MPa, and the water absorption increased by about 2 %. The addition of starch increased the Tmax by 8.1–29.64 °C compared to pure PVA. Considering the mechanical, hydrophilic and optical properties of the blend films, PVA/starch at 7:3 was the most promising packaging material. Notably, the blend films exhibit great reusability and renewability. Overall, these findings highlight the potential of PVA/starch blend films as environmentally friendly materials with enhanced properties.

End-to-end, decision-based, cardinality-constrained portfolio optimization

Portfolios employing a (factor) risk model are usually constructed using a two step process: first, the risk model parameters are estimated, then the portfolio is constructed. Recent works have shown that this decoupled approach may be improved using an integrated framework that takes the downstream portfolio optimization into account during parameter estimation. In this work we implement an integrated, end-to-end, predict-&-optimize framework to the cardinality-constrained portfolio optimization problem. To the best of our knowledge, we are the first to implement the framework to a nonlinear mixed integer programming problem. Since the feasible region of the problem is discontinuous, we are unable to directly differentiate through it. Thus, we compare three different continuous relaxations of increasing tightness to the problem which are placed as an implicit layers in a neural network. The parameters of the factor model governing the problem’s covariance matrix structure are learned using a loss function that directly corresponds to the decision quality made based on the factor model’s predictions. Using real world financial data, our proposed end-to-end, decision based model is compared to two decoupled alternatives. Results show significant improvements over the traditional decoupled approaches across all cardinality sizes and model variations while highlighting the need of additional research into the interplay between experimental design, problem size and structure, and relaxation tightness in a combinatorial setting.

A model of knowledge chain integration for complex product R&amp;D projects based on DSM and TCPN

AbstractComplex product research and development projects usually are large scale with high cost and complex technologies and with large number of group members involved. From the perspective of complex system management, this paper adopts design structure matrix and timing constraint Petri nets (TCPN) to analyse knowledge behaviour and time constraints of team members in complex product R&amp;D projects. In specific, this paper first develops a knowledge‐activity design structure matrix and a time‐resource design structure matrix model. Then a TCPN model that integrates resource constraints in knowledge chains is proposed based on the dependence relationship of team members' knowledge activities. Schedulabilities of the model are calculated, analysed and corrected to integrate team members' knowledge. Finally, a case study is conducted to test the proposed model.

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.