Modification Of Matrix Research Articles

Pelabelan Total Titik Ajaib Pada Graf Tangga

The labeling of a graph is a mapping that pairs the elements in the graph into positive integers. In this thesis, it discusses how the magic total point labeling algorithm on the ladder graph and the ladder graph and how the magic total point labeling on the ladder graph and the adder graph uses the magic square matrix modification using the durer method. Where the elements of the result of this magic square matrix modification will be used as point labels on the ladder graph and the ladder graph.

How will future climates in the Pakistani Punjab rice-wheat system affect the optimal agronomic settings, and can adaptation offset losses?

Pakistan is one of the most vulnerable countries in the world to future climatic changes, already with significant water and food sustainability issues. Rice and wheat production in the Pakistani Punjab is central to national food security and hence of particular concern. We sought to understand what optimal rice-wheat (RW) farmer agronomic practices (those which maximise RW system gross margins (GM) and irrigated water productivity (WPi)) look like under each of 6 projected future climate change scenarios for mid-century (2050). We also examined the impact on 2050 RW production if current farmer practices remained unchanged, to gauge the potential benefits of the optimal adaptations. Cropping systems simulation with a validated model (APSIM) enabled analysis of a broad range of current management practice modifications (6 agronomic management settings parameters, including crop sowing dates, varieties, fertiliser rates, and deficit irrigation strategies) in a large Monte-Carlo Matrix (96,768 elements) for the highest-yielding district in the Punjab, Gujranwala. We evaluated annual crop production, GM, WPi, nitrate leaching, and total system evapotranspiration (ET) for all combinations on an annual basis over a 31-year simulation period for each future climate scenario (as well as the historical record) seeking optimal parameter combinations within each. If current farmer practices were to remain unchanged into the future, we found reductions in farmer GM’s by 35–50% by 2050, with WPi decreasing even further (40–60%). Adaptation of current RW management practices is therefore essential. By adopting optimal practices now (derived using the historical climate record) we found that farmers also place themselves well for future climates and our study suggests they can maintain or maybe even increase current GM’s by 5–30% (depending on climate scenario) through smart adaptation. The best agronomic practices in 2050 look almost indistinguishable from the best agronomic practices now, regardless of future climate scenario chosen. However, compared with a hypothetical farmer operating under optimal practices now, our study suggests that a farmer in 2050 will earn considerably less, with gross margins under optimal practices falling by 25–40%, depending on which future climate scenario is considered. Declines are largely due to falling rice yields under future conditions (20–50% across examined climate scenarios), with wheat yields likely to be maintained or even slightly increased. Our study also indicated an increase in ET (10–15%) across all RW practices (regardless of future climate scenario and despite projections for generally reduced rainfall, runoff and drainage), compared with historical conditions. Our study suggests a rice varietal improvement need for heat tolerance, but that current wheat varieties are suitable to 2050.

Structural, thermal, and mechanical characterisation of PEEK-based composites in cryogenic temperature

Thermal, thermo-mechanical and mechanical properties of four different commercially available polyetheretherketones (PEEK) based materials were investigated. PEEK matrix was either modified and/or reinforced with carbon fibres, graphite and/or PTFE. Impact strength was measured at three different temperatures: 25 °C, −100 °C, and −195 °C. At 25 °C, thermal stability and mechanical properties, including the elastic modulus, compression, and impact strength, were enhanced with the addition of carbon fibres. Matrix modification had a minor impact on thermal stability, while the mechanical properties decreased, except for impact strength. At −100 °C, the mechanical properties of the neat polymers were improved, including increased impact strength by 20% compared to values at 25 °C. Addition of fillers hindered the rise of impact strength due to complex mechanisms caused by different coefficients of thermal expansion of reinforcements and matrix. At −195 °C, the significant increase of impact strength was revealed for unmodified PEEK reaching 30 times higher values than at 25 °C, while matrix modification suppressed the rise of impact strength. The scratch test indicated the superior behaviour of unfilled PEEK during the tested load range (up to 15 N), while the effect of the fillers was observed at much lower load threshold of 7 N.

An investigation on effect of ultraviolet (UV) rays on mechanical properties of epoxy laminates

The use of epoxy resins has significantly grown in many industrial applications due to their exceptional mechanical and chemical properties. However, their susceptibility to Ultraviolet (UV) light damage and exposure to outdoor weather conditions remains a major limitation. In order to address this drawback, UV absorbers have been frequently employed to reduce the rate of UV degradation. This study investigates the impact of UV radiation on the physical, chemical, and mechanical characteristics of cured epoxy laminates. The results indicate that UV radiation causes a significant reduction in tensile strength by 22.6% after 180 h of exposure. Furthermore, UV–Visible and Fourier-transform infrared spectroscopy (FTIR) spectroscopy measurements demonstrate significant chemical and optical modifications in the epoxy matrix, leading to the deterioration of its properties. These findings provide valuable insights for designing new epoxy formulations that can withstand harsh environmental conditions and improve the durability and performance of epoxy-based products.

Modification of epoxy resin matrix by high-performance mesoporous silica@graphene nanocomposites

Modification of epoxy resin matrix by high-performance mesoporous silica@graphene nanocomposites

Antimicrobial and Wound Healing Effects of Metal Oxide Nanoparticles-Enriched Wound Dressing

Taking care of wounds costs a lot of money. A significant medical problem is the treatment of burns, surgical and trauma wounds and skin wounds, with current therapies primarily emphasizing supportive care techniques. Coagulation, inflammation, angiogenesis, new tissue creation and extracellular matrix modification are necessary processes for successful wound healing. Metal oxides (Titanium, Silver, Zinc, Copper, Magnesium, Nickel) with potent antibacterial and healing characteristics can be employed as nanomaterials in dressings. Metal oxide nanoparticles (MeO-NPs) have a wide range of physicochemical properties that allow them to function as antimicrobial agents through a variety of mechanisms. The treatment of lethal infectious diseases will be impacted by the enormous variety of features demonstrated by MeO-NPs. This study covers the antibacterial mechanisms of common MeO-NPs, factors affecting their antibacterial activity and their role in accelerating wound healing.

Note on a rank-one modification of the singular value decomposition

In this paper, we investigate the singular value decomposition (SVD) of Σ+xyH, where Σ is an m×n real diagonal matrix, x∈Cm, and y∈Cn. We start by briefly revisiting an existing approach for determining the desired SVD by sequentially computing the eigendecomposition of two separate hermitian rank-one modifications of a real diagonal matrix. Then we introduce the notion of the rank-two secular functionwhose roots are the singular values of Σ+xyH and exploit its properties to bound each root/singular value in disjoint intervals. Once the singular values are computed, we demonstrate how to directly compute the full set of associated left/right singular vectors ultimately giving us a new method for computing the SVD of Σ+xyH in O(min(m,n)2) time.

Exploring the Communication of the SASP: Dynamic, Interactive, and Adaptive Effects on the Microenvironment

Cellular senescence is a complex cell state that can occur during physiological ageing or after exposure to stress signals, regardless of age. It is a dynamic process that continuously evolves in a context-dependent manner. Senescent cells interact with their microenvironment by producing a heterogenous and plastic secretome referred to as the senescence-associated secretory phenotype (SASP). Hence, understanding the cross-talk between SASP and the microenvironment can be challenging due to the complexity of signal exchanges. In this review, we first aim to update the definition of senescence and its associated biomarkers from its discovery to the present day. We detail the regulatory mechanisms involved in the expression of SASP at multiple levels and develop how SASP can orchestrate microenvironment modifications, by focusing on extracellular matrix modifications, neighboring cells’ fate, and intercellular communications. We present hypotheses on how these microenvironmental events may affect dynamic changes in SASP composition in return. Finally, we discuss the various existing approaches to targeting SASP and clarify what is currently known about the biological effects of these modified SASPs on the cellular environment.

Covalent Modification of Nanoparticle‐Imprinted Matrices for Selective Nanoparticle Recognition

AbstractNanoparticle‐imprinted matrices (NAIMs) were prepared using ammonium‐terminated SiO2 nanoparticles (NPs) as templates initially attached to activated glassy carbon. After electrodeposition of a matrix of polyplumbagin and polyphenol, the selectivity of the polymer matrix was tuned towards the ligand shell of the Au analyte NPs by conjugate addition of substituted thiols to the plumbagin moiety within the matrix. The reactions were followed by cyclic voltammetry (CV) and the presence of thiols and amino groups in the film was verified by X‐ray photoelectron spectroscopy (XPS). After dissolution of the template NPs, the matrix had complementary cavities for the uptake of Au NPs. The amount of Au NP inside the cavities was quantified by the charge transferred during electrodissolution of the Au NPs in 3 M KCl in linear sweep voltammetry, which depended on the covalent modification of the polyplumbagin matrix, the pH during uptake and the size of the Au analyte NPs. The NAIM system modified with 1,2‐ethanedithiol showed the best uptake with 9.6×107 NPs cm−2 at pH 10, which is five times higher than the uptake of the same matrix at pH 5. In contrast, the cysteamine‐modified NAIM exhibited the highest uptake at pH 5.

LFV Higgs and Z-boson decays: leptonic CPV phases and CP asymmetries

Heavy neutral leptons are motivated by several extensions of the Standard Model and their presence induces modifications in the lepton mixing matrix, including new Dirac and Majorana CP violating phases. It has been recently shown that these phases play an important role in lepton number and lepton flavour violating decays and transitions, with a striking impact for the predicted rates of certain observables. In this work, we now consider the potential role of the heavy neutral fermions and of the new CP violating phases in Higgs and Z-boson lepton flavour violating decays H,Zrightarrow ell _alpha ^pm ell _beta ^mp , as well as in the corresponding CP asymmetries. In order to allow for a thorough analysis, we derive the full analytical expressions of the latter observables, taking into account the effect of the (final state) charged lepton masses. A comprehensive exploration of lepton flavour violating Z and Higgs decays confirms that these are very sensitive to the presence of the additional heavy neutral leptons. Moreover, the new CPV phases have a clear impact on the decay rates, leading to both destructive and constructive interferences. Interestingly, in the mu tau sector, the Zrightarrow ell _alpha ^pm ell _beta ^mp rates are within reach of FCC-ee, with associated CP asymmetries that can potentially reach up to 20–30%.

A parametrization of structure-preserving transformations for matrix polynomials

Given a matrix polynomial A(λ) of degree d and the associated vector space of pencils DL(A) described in Mackey et al. [12], we construct a parametrization for the set of left and right transformations that preserve the block structure of such pencils. They form a special class of structure-preserving transformations (SPTs). An SPT in that class maps DL(A) to DL(A˜), where A˜(λ) is a new matrix polynomial that is still of degree d and whose finite and infinite eigenvalues and their partial multiplicities are the same as those of A(λ). Unlike previous work on SPTs, we do not require the leading matrix coefficient of A(λ) to be nonsingular. We show that additional constraints on the parametrization lead to SPTs that also preserve extra structures in A(λ) such as symmetric, alternating, and T-palindromic structures. Our parametrization allows easy construction of SPTs that are low-rank modifications of the identity matrix. The latter transform A(λ) into a matrix polynomial A˜(λ) whose jth matrix coefficient A˜j is a low-rank modification of Aj. We expect such SPTs to be one of the key tools for developing algorithms that reduce a matrix polynomial to Hessenberg form or tridiagonal form in a finite number of steps and without the use of a linearization.

Evaluation of Blockchain-Based Crowdfunding Campaign Success Factors Based on VASMA-L Criteria Weighting Method

When investing in blockchain-based crowdfunding campaigns, choosing the right one is difficult. Therefore, it is important to recognize success factors that express the value of the specific campaign. This study is aimed at determining the success factors impacting the investors’ decision to fund blockchain-based crowdfunding campaigns and ranking them according to their importance in decision-making. An online survey was employed to collect expert opinions. The modification of the visual analogue scale matrix for criteria weighting methodology called VASMA-L was presented in this study to rank the list of the predetermined factors. To reduce the uncertainties in the decision-making process and the cognitive overload of the survey respondents, all the predetermined success factors were split into two smaller groups and assessed as those that fit both traditional and blockchain-based crowdfunding models and those that are specific only to the blockchain-based crowdfunding model. The main findings disclose that the three factors with the highest VASMA weights are from the first group. This means that when selecting the specific crowdfunding campaign to invest in, investors use common factors rather than those specific to blockchain-based crowdfunding. Only investor preferences were chosen and analyzed for successful blockchain-based crowdfunding campaign investment in this research. The VASMA-L methodology might help compare several criteria groups and select the most important ones. In addition, this weighting methodology might help investors to choose the most thrilling blockchain-based crowdfunding campaigns to fund.

Dynamic modulation of matrix adhesiveness induces epithelial-to-mesenchymal transition in prostate cancer cells in 3D

Synthetic matrices with dynamic presentation of cell guidance cues are needed for the development of physiologically relevant in vitro tumor models. Towards the goal of mimicking prostate cancer progression and metastasis, we engineered a tunable hyaluronic acid-based hydrogel platform with protease degradable and cell adhesive properties employing bioorthogonal tetrazine ligation with strained alkenes. The synthetic matrix was first fabricated via a slow tetrazine-norbornene reaction, then temporally modified via a diffusion-controlled method using trans-cyclooctene, a fierce dienophile that reacts with tetrazine with an unusually fast rate. The encapsulated DU145 prostate cancer single cells spontaneously formed multicellular tumoroids after 7 days of culture. In situ modification of the synthetic matrix via covalent tagging of cell adhesive RGD peptide induced tumoroid decompaction and the development of cellular protrusions. RGD tagging did not compromise the overall cell viability, nor did it induce cell apoptosis. In response to increased matrix adhesiveness, DU145 cells dynamically loosen cell-cell adhesion and strengthen cell-matrix interactions to promote an invasive phenotype. Characterization of the 3D cultures by immunocytochemistry and gene expression analyses demonstrated that cells invaded into the matrix via a mesenchymal like migration, with upregulation of major mesenchymal markers, and down regulation of epithelial markers. The tumoroids formed cortactin positive invadopodia like structures, indicating active matrix remodeling. Overall, the engineered tumor model can be utilized to identify potential molecular targets and test pharmacological inhibitors, thereby accelerating the design of innovative strategies for cancer therapeutics.

Novel Iron Oxide Nanoparticle-Fortified Carbon Paste Electrode for the Sensitive Voltammetric Determination of Atomoxetine.

Herein, the fabrication and full characterization of a novel atomoxetine (ATX) voltammetric carbon paste electrode (CPE) fortified with iron oxide nanoparticles (FeONPs) is demonstrated. Modification of the carbon paste matrix with the metallic oxide nanostructure provides proper electrocatalytic activity against the oxidation of ATX molecules at the carbon paste surface, resulting in a noticeable improvement in the performance of the sensor. At the recommended pH value, ATX recorded an irreversible anodic peak at 1.17 V, following a diffusion-controlled reaction mechanism. Differential pulse voltammograms exhibited peak heights linearly correlated to the ATX content within a wide concentration range from 45 to 8680 ng mL-1, with the limit of detection reaching 11.55 ng mL-1. The electrooxidation mechanism of the ATX molecule was proposed to be the oxidation of the terminal amino group accompanied by the transfer of two electrons and two protons. The fabricated FeONPs/CPE sensors exhibited enhanced selectivity and sensitivity and therefore can be introduced for voltammetric assaying of atomoxetine-indifferent pharmaceutical and biological samples in the presence of its degradation products and metabolites.

Blast failure and energy analysis of rubber-modified carbon-fiber vinyl-ester composite laminates

Modifications in vinyl ester resins, a popular matrix resin choice in naval applications through rubber additives, are being experimentally investigated in the current study. Toughening of the composite matrix resin using additives has been a popular choice, where it has been postulated that the inherent modifications to the base resin polymer would enhance the overall response of the composite structure to dynamic loadings. This work intends to understand the effect of such matrix modifications on the shock response of composite panels and the failure mechanism of a composite plate subjected to air shock loading. The study comprises material fabrication, resin and composite material characterization, and analysis of composite panels' response and damage evaluation under a range of shock loadings. A shock tube apparatus is used to generate controlled shock on composite laminates with fixed-fixed boundary conditions. In conjuncture, a high-speed 3-D DIC camera system is used to obtain full-field deformation and strain fields on the specimen's back face (furthest from the loading face). Based on the structural response and energy analysis, the effect of rubber modification is quantified and compared with non-modified resin composites, where the change is shown to improve the structural damping and energy dissipation under below-failure shock loadings and further shows relatively limited crack growth under high-intensity shock loadings.

Advances in atomic oxygen resistant polyimide composite films

Polyimide (PI) film is an attractive space material used in low Earth orbit (LEO) environment, owing to its extraordinary thermal, chemical stability, flexibility, excellent mechanical and insulating properties. These superior properties and versatility make PI one of the indispensable materials ensure the normal operation of spacecraft, which are unparalleled by most other polymers. Hydrocarbon-based PI, however, cannot withstand the erosion of atomic oxygen (AO) in LEO. Up to now, many strategies including coating, matrix modification and structural design have been utilized to improve the AO resistance of PI film. This review summarizes the state-of-the-art works on the PI composite films with AO resistance, and discusses the advantages and disadvantages of different strategies for protecting PI matrix from AO erosion. First, we discuss the conventional coatings protection, which contains inorganic, organic and organic–inorganic coatings. Then, the focus is attached to improving the inherent anti-AO capacity of PI film through matrix modifications, such as intrinsic, blending and doping modification strategies. Finally, the structural design strategies including Janus structure and bioinspired microstructure are also discussed. Fundamental parameters of PI composite films, such as mass loss, erosion yield, as well as mechanical properties, are highlighted to evaluate their anti-AO ability. Inspired by investigations over the past decades, a roadmap is also carefully depicted for the future of AO-resistant PI composite films in fundamental research.

Damage characterisation of amine-functionalized MWCNT reinforced carbon/epoxy composites under indentation loading

Damage resistance of carbon fibre reinforced composites is crucial parameter to be considered at both primary selection and in-service maintenance stages. High stiffness of carbon-epoxy system and stacked configuration make it susceptible to impact induced brittle damages. Delamination is one such life-limiting damage modes that can severely inhibit load carrying capacity of laminates. Hence to improve the damage resistance of composites demands tailoring tough microstructure and altering brittle damage modes with ductile ones. This work attempted to design damage resistant carbon composites through modification of epoxy matrix with amine functionalized multi walled carbon nanotubes (NH2-MWCNT). Laminates with different nanotube concentrations (0.3, 0.6, 0.9 and 1.2 wt. %) were fabricated to investigate its influence on load bearing capacity, toughness and damage resistance of fibre reinforced nanocomposites. Generally, peak force, displacement and toughness until maximum force improved at all nanoparticle concentrations. Matrix cracking was suppressed owing to optimum cross-linking of nanoparticle with matrix. External damage area increased with nanoparticle concentration although delaminated area, mapped through c-scan, was suppressed up to 27.73%. A combination of higher degree of interfacial interactions, induced by nanoparticles, and energy absorbing microstructure was concluded to be behind improvement in the damage resistance of composites.

Sulfonated PAM/PPy Cryogels with Lowered Evaporation Enthalpy for Highly Efficient Photothermal Water Evaporation.

Because of the increasing scarcity of water resources, the desalination of seawater by photothermal evaporation with harvested solar energy has gradually become a popular research topic. The interconnected macroporous cryogel prepared from polymerization and crosslinking below the freezing temperature of the reactant solution has an excellent performance in photothermal water evaporation after loading photothermal materials. In this study, polyacrylamide (PAM) cryogels were prepared by cryo-polymerization and sulfonated in an alkaline solution containing formaldehyde and Na2SO3. Importantly, the evaporation enthalpy of water in sulfonated PAM cryogel was reduced to 1187 J·g-1 due to the introduction of sulfonate groups into PAM, which was beneficial to increase the photothermal evaporation rate and efficiency. The sulfonated PAM cryogels loaded with polypyrrole and the umbrella-shaped melamine foam substrate were combined to form a photothermal evaporation device, and the evaporation rate was as high as 2.50 kg·m-2·h-1 under one-sun radiation. Meanwhile, the evaporation rate reached 2.09 kg·m-2·h-1 in the 14 wt% high-concentration saline solution, and no salt crystals appeared on the surface of the cryogel after 5 h of photothermal evaporation. Therefore, it was evidenced that the presence of sulfonate groups not only reduced the evaporation enthalpy of water but also prevented salting-out from blocking the water delivery channel during photothermal evaporation, with a sufficiently high evaporation rate, providing a reliable idea of matrix modification for the design of high-efficiency photothermal evaporation materials.

In Situ P-Modified Hybrid Silica–Epoxy Nanocomposites via a Green Hydrolytic Sol–Gel Route for Flame-Retardant Applications

Flame retardance of epoxy resins is usually imparted using suitable additives and/or properly modified curing agents. Herein, via a two-step green synthetic procedure, the chemical modification of the epoxy matrix with reactive silicon and phosphorus precursors is explored to obtain nanocomposites with intrinsic flame-retardant features. Nanoscale phase separation occurs in the first step, forming an inverse micelle system in which polar nanodomains act as nanoreactors for the hydrolysis of silanes (Si precursors), giving rise to silica lamellar nanocrystals (SLNCs). In the second step, inside the silica nanodomains, the formation of stable Si–O–P bonds occurs because the reactivity of phosphoric acid (P precursor) with the oxirane rings of the polymer chain is balanced by its tendency to diffuse into polar nanodomains. Intriguingly, the use of phosphoric acid alone in epoxy composite manufacturing leads to a wormlike morphology of the network, whereas its addition in the presence of silanes results in the formation of SLNCs with a thinner interlayer distance. The morphology of the hybrid Si/P–epoxy nanocomposites, comprising organic and inorganic co-continuous phases, can confer, through a prevalent mechanism in the condensed phase, interesting flame-retardant performances, namely, the absence of dripping during vertical burning tests, the formation of a large amount of coherent char after combustion, and a remarkable reduction (up to 27.7%) in the peak of heat release rate. The above characteristics make these nanostructured hybrid materials very promising for the manufacturing of epoxy systems with enhanced fire behavior (e.g., coatings, sealants, matrices for reinforced composites), even containing a low amount of specific flame retardants and thus keeping good viscoelastic properties.

Effect of nonwoven interlayer melting temperature and matrix toughness on mode I and mode II fracture toughness of carbon fiber/benzoxazine composites

Two toughening approaches were investigated in this study to improve the interlaminar fracture toughness (ILFTs) of carbon fiber/benzoxazine composites. A matrix modification as well as an incorporation of thermoplastic polyamide (PA) veils were utilized to investigate the change in the ILFT properties. Two PA veils with different melting temperatures were analyzed and the ILFT properties of the resultant laminates were determined by the Mode-I and Mode-II critical strain energy release rates (GIC and GIIC). The incorporation of both veils was found to increase both GIC and GIIC performances. The veil with a lower melting temperature than the curing temperature of the resin resisted a Mode-I crack propagation better than the veil with a high-melting temperature. A significant increase in the GIC measurements could therefore be achieved with the use of the toughened matrix system. In the Mode-II ILFT testing, the high-melting temperature veil outperformed the low-melting temperature veil in resisting both crack initiation and propagation. No significant toughening improvement was observed with the use of a toughened matrix system in the Mode-II experiment. A combination between matrix toughening and interleaving with the high-melting temperature veil led to an enhancement in Mode-II properties. The fracture surfaces of the tested specimens were then examined for a determination of toughening effects of the interleaved veils on the composites.