Weak Matrix Research Articles

A strength inversion origin for non-volcanic tremor

Non-volcanic tremor is a particularly enigmatic form of seismic activity. In its most studied subduction zone setting, tremor typically occurs within the plate interface at or near the shallow and deep edges of the interseismically locked zone. Detailed seismic observations have shown that tremor is composed of repeating small low-frequency earthquakes, often accompanied by very-low-frequency earthquakes, all involving shear failure and slip. However, low-frequency earthquakes and very-low-frequency earthquakes within each cluster show nearly constant source durations for all observed magnitudes, which implies characteristic tremor sub-event sources of near-constant size. Here we integrate geological observations and geomechanical lab measurements on heterogeneous rock assemblages representative of the shallow tremor region offshore the Middle America Trench with numerical simulations to demonstrate that these tremor events are consistent with the seismic failure of relatively weaker blocks within a stronger matrix. In these subducting rocks, hydrothermalism has led to a strength-inversion from a weak matrix with relatively stronger blocks to a stronger matrix with embedded relatively weaker blocks. Tremor naturally occurs as the now-weaker blocks fail seismically while their surrounding matrix has not yet reached a state of general seismic failure.

Enzyme-powered nanomotors with enhanced cell uptake and lysosomal escape for combined therapy of cancer

Low cellular uptake and lysosomal degradation are key difficulties of drug delivery in cancer treatment. Here, we report a novel nanomotor which can accomplish self-propulsion under the tumoral endogenous hydrogen peroxide to achieve high cell uptake rate and lysosomal escape. Calcium carbonate nanoparticles were employed as the core with polyethyleneimine (PEI) and catalase (CAT) acting as the shell to prepare the nanomotor via layer-by-layer self-assembly technology. To achieve local administration and slow release inside tumor, the nanomotors were loaded in Schiff-base hydrogel to build NM@hydrogel system. Taking advantage of the tumor microenvironment featured with an acidic pH and a high amount of hydrogen peroxide, the nanomotors were released from NM@hydrogel system in response to weak acidic tumor matrix. The released nanomotors can be autonomously propelled by the oxygen gradient generated from catalytic decomposition of hydrogen peroxide with a speed at 10.1±1.1 µm/s in 0.1 mM H2O2. Furtherly, combined with autonomous motion of nanomotors, specific tumor affinity strategy mediated by folic acid (FA) modification on the nanomotors was also proposed in the NM@hydrogel system, which the cell uptake rate was enhanced to about 80.6±2.0%. Furthermore, after internalization, the nanomotors could also efficiently escape from lysosomes owing to the proton sponge effect caused by PEI, CO2 produced by the degradation of CaCO3 nanoparticles and autonomous motion, which facilitated PTX and siRNA to reach their intracellular target, tubulin. PTX and siRNA strongly affected properties of tubulin and resulted in tumor cell apoptosis. In vitro and in vivo studies demonstrated excellent antitumor effect of the NM@hydrogel. Therefore, we anticipate that the proposed system would provide new insight in the drug delivery for cancer treatment.

Continuous fibre composite 3D printing with pultruded carbon/PA6 commingled fibres: Processing and mechanical properties

Continuous Fibre composite 3D printing (CF-3DP) technology is a newly developed Additive Manufacturing (AM) process. By employing continuous fibre as a reinforcement for the composite, the mechanical properties of the 3D printed part can be significantly improved. However, owing to the process's early stage of development, the mechanical performance of the printed material is still unable to compete with composites produced using conventional manufacturing processes. This can manly be attributed to lower fibre volume fractions and/or higher void content. The grand objective of the research project is to establish a demonstrator of practical applications, and in this paper, preparatory developments were carried out to pave the ground for the subsequent developments, including feedstock materials development, printing process development, and materials properties evaluation. Efforts has been made to increase fibre volume fracture, to reduce voids contents, to evaluate effective properties systematically. The static mechanical test results showed relatively good longitudinal tensile properties while matrix sensitive properties were low, as to be expected in UD composites with a relatively weak matrix material. The advantage of CF-3DP is to achieve fibre steering, and the steered fibre design can be achieved by the current process to realize novel composite structures in future study.

Form factors for the processes Bc+→D0ℓ+νℓ and Bc+→Ds+ℓ+ℓ−(νν¯) from lattice QCD

We present results of the first lattice QCD calculations of the weak matrix elements for the decays $B_c^+ \to D^0 \ell^+ \nu_{\ell}$, $B_c^+ \to D_s^+ \ell^+ \ell^-$ and $B_c^+ \to D_s^+ \nu \overline{\nu}$. Form factors across the entire physical $q^2$ range are then extracted and extrapolated to the continuum limit with physical quark masses. Results are derived from correlation functions computed on MILC Collaboration gauge configurations with three different lattice spacings and including 2+1+1 flavours of sea quarks in the Highly Improved Staggered Quark (HISQ) formalism. HISQ is also used for all of the valence quarks. The uncertainty on the decay widths from our form factors is similar in size to that from the present value for $V_{ub}$. We obtain the ratio $\Gamma (B_{c}^{+} \rightarrow D^0 \mu^{+} \nu_{\mu}) /\left|\eta_{\mathrm{EW}} V_{u b}\right|^{2}=4.43(63) \times 10^{12} \mathrm{~s}^{-1}$. Combining our form factors with those found previously by HPQCD for $B_{c}^{+} \rightarrow J / \psi \mu^{+} \nu_{\mu}$, we find $\left|V_{cb}/V_{ub} \right|^2 \Gamma( B_c^+ \to D^0 \mu^+ \nu_\mu )/\Gamma(B_{c}^{+} \rightarrow J / \psi \mu^{+} \nu_{\mu}) = 0.257(36)_{B_c \to D}(18)_{B_c \to J/\psi}$. We calculate the differential decay widths of $B_c^+ \to D_s^+ \ell^+ \ell^-$ across the full $q^2$ range, and give integrated results in $q^2$ bins that avoid possible effects from charmonium and $u \overline{u}$ resonances. For example, we find that the ratio of differential branching fractions integrated over the range $q^2 = 1 \; \mathrm{GeV}^2 - 6 \; \mathrm{GeV}^2$ for $B_c^+ \to D_s^+ \mu^+ \mu^-$ and $B_{c}^{+} \rightarrow J / \psi \mu^{+} \nu_{\mu}$ is $5.23{\tiny }(73)_{B_c \to D_s}(54)_{B_c \to J/\psi} \times 10^{-6}$. We also give results for the branching fraction of $B_c^+ \to D_s^+ \nu \overline{\nu}$. Prospects for reducing our errors in the future are discussed.

On Consistent and Weak Transitive Intuitionistic Fuzzy Matrices

In this paper, we discuss in detail several properties of two kinds of intuitionistic fuzzy matrices which they are consistent and weak transitive. The nilpotent and transitive intuitionistic fuzzy matrices play an important role in this discussion. We show that our two kinds of matrices are controllable. We give a formula for the canonical form of a weak transitive intuitionistic fuzzy matrix. Our results are completely by counter examples to clarify it.

Further characterizations of the weak core inverse of matrices and the weak core matrix

<abstract><p>The present paper is devoted to characterizing the weak core inverse and the weak core matrix using the core-EP decomposition. Some new characterizations of the weak core inverse are presented by using its range space, null space and matrix equations. Additionally, we give several new representations and properties of the weak core inverse. Finally, we consider several equivalent conditions for a matrix to be a weak core matrix.</p></abstract>

Application of Functional Tests in the Prevention from Musculoskeletal Injuries in Young Classical Style Wrestlers

Backgorund: Wrestling is a contact sport with a high risk of injury occurrence caused by typical motor system dysfunctions. In wrestling training a high value is put on the development of power and muscle strength, however, a program aimed at improving motor control is not introduced. Methods: The study involved 25 men wrestlers from School of Sporting Excellence in Radom Poland. To identify musculoskeletal system weak links low threshold Performance Matrix Tests were used. An analysis of weak links occurrence in biokinematics chain was done using ANalysis Of Variance (ANOVA), location and direction of weak links occurrence was identified. Results: The low threshold tests provide the information that tested athletes (n = 25) have weak links in musculoskeletal system. Players training experience has significant influence on their occurrence Pr (>F) 0.01809. The values p3 = Pr (>F) 0.03215 and p5 = Pr (>F) 0.04042 reflect significant correlation with occurrence of weak links number in various places in wrestlers musculoskeletal system. The results Pr (>F) for training frequency, wrestlers age and sports level indicate no significant effect of these characteristics on weak links location in musculoskeletal system. Conclusions: Obtained results lead to the following conclusions: (1) training loads in wrestling cause weak links occurrence in musculoskeletal system among juniors; (2) wrestlers training in junior category significantly affects weak links occurrence in chain of musculoskeletal system in different locations; (3) wrestlers training frequency does not have a significant impact on weak links location estimated by low threshold tests.

Changes in Gel Structure and Chemical Interactions of Hypophthalmichthys molitrix Surimi Gels: Effect of Setting Process and Different Starch Addition.

The modifications of histological properties and chemical forces on heated surimi gels with starch addition (0–12 g/100 g surimi) were investigated. Two types of heating processes (direct heating and two-step heating) were carried out on surimi gels in order to reveal the effect of setting on mixed matrices. The results of transverse relaxation time showed less immobile water and free water converted into bound water in a matrix subjected to the setting process. Scanning electron microscope and light microscopy images revealed inefficient starch-swelling in two-step heated gels. Chemical interactions and forces in direct cooking gels were more vulnerable to starch addition, resulting in significant decreases in hydrophobic interaction and sulfhydryl content (p < 0.05). With the increment of starch, the disulfide stretching vibrations of the gauche–gauche–gauche conformation were reduced in both gel matrices. The structural variations of different components collectively resulted in changes in texture profile analysis and water holding capacity. Overall, the results demonstrated that starch addition had a great and positive effect on the weak gel matrix by direct heating.

Selection of proper matrix with plasma-treated HTPP fiber reinforced cementitious composites in terms of flexural toughness

In this study the influence of matrix type on plasma-treated high tenacity polypropylene fiber reinforced cementitious composites were investigated. The fibers were subjected to low frequency cold plasma of oxygen gas. Power rate of the generator was 50, 100 and 200 W, and duration was 0.5, 2 and 20 min. 25 × 60 × 300 mm prismatic samples were prepared with two type of matrices, and plasma-treated/untreated fibers. Scanning electron microscope was used to determine physical modifications on the fibre surface. Four point bending tests were conducted on prismatic samples. Matrices with treated and untreated fiber reinforcement were compared by means of flexural properties. Analysis of variences was applied to the plasma treated fiber reinforced groups. Test results showed that the flexural behaviour of composites was affected by plasma power and duration. There was physical modification for each plasma power and duration. The influence of plasma treatment on fiber-matrix bond properties was mainly affected by matrix type: weak matrix showed better flexural properties with low power and short duration plasma-treated fibers, whereas comparatively stronger matrix expressed greater flexural properties at higher power and longer durations when compared to untreated fiber reinforced composites.

Evaluation of mechanical properties of a dense SiC/SiCN composite produced via PIP process

The material behavior of Polymer Infiltration and Pyrolysis based SiC/SiCN composites is studied and the characteristic thermal and mechanical properties in on- (0/90 °) and off-axis (±45 °) direction are summarized. The tensile properties are determined at room temperature and 1300 °C. Based on the ratio of Young’s modulus and strength between on- and off-axis loading, a new approach for the classification of Weak Matrix Composites (WMC) and Weak Interface Composites (WIC) is proposed, which seems to be reasonable for various CMCs. Even without fibre coating mechanical behavior of SiC/SiCN is similar to that of WIC. In order to explain this, a microstructure model is developed and confirmed by analysis of fracture surface. The effect of temperature on the tensile properties is investigated through analysis of residual thermal stresses. Even though at 1300 °C the strength is slightly lower, the fracture strain increased significantly from RT to 1300 °C.

Short fiber‐reinforced oxide fiber composites

AbstractThis paper presents a novel fiber spraying process for the manufacturing of short fiber bundle‐reinforced Nextel™ 610/Al2O3‐ZrO2 oxide fiber composites (SF‐OFC) and its characterization. First, the influence of varying fiber lengths (7, 14, and 28 mm, continuous fibers) and fiber orientations (unidirectional 0°, quasi‐isotropic, ±45°) was investigated using hand‐laid SF‐OFC. Due to the weak matrix, the hand‐laid material exhibited a strongly fiber‐dominated material behavior, that is, variations in fiber length and orientation had a strong influence on the material properties. Second, the automated sprayed SF‐OFC, however, exhibited a random orientation of the fiber bundles, which resulted in in‐plane isotropic material properties. Average bending strengths of up to 177 MPa, strains of .39%, and a quasi‐ductile fracture behavior were achieved. The strain was, therefore, in the range of fabric‐reinforced OFC. While the bending strength of the SF‐OFC was somewhat lower than that of fabric‐reinforced OFC with the fiber orientation parallel to the loading direction, it was more than two times higher than the strength in 45° direction relative to the fabric reinforcement. Combined with good drapability and lower material costs compared to fabric‐reinforced OFC, SF‐OFC is, therefore, a promising material for industrial applications.

ε-Poly-l-lysine as an efficient cartilage penetrating and residing drug carrier with high intraarticular injection safety for treating osteoarthritis

A major reason that hinders the clinical application of disease-modifying osteoarthritis drugs (DMOADs) is the unmet challenges in their effective delivery to cartilage. Cationic macromolecules represent promising carriers to enhance the drug delivery to cartilage through their electrostatic interaction with the negatively charged cartilage matrix. However, current candidate cationic macromolecular carriers (CMCs) must solve the intractable challenges in scalable production and biosafety before they can be used clinically. ε-poly-l-lysine (ε-PLL) is a unique poly (amino acid) that has favorable features to conquer the above issues. In this study, we evaluated the potential of ε-PLL as a cost effectiveness, biosafety, and effective CMC for drug delivery to cartilage. Cartilage explant from pig knee was used as a model for the in vitro analysis of ε-PLL’s interaction with, penetration into, and resident in cartilage tissue. The results showed that ε-PLL had a strong distribution tendency in cartilage with partition coefficient K ∼ 4.3 and weak cartilage matrix binding ability (KD ∼ 310 μM) with abundant intra-cartilage binding sites (N ∼ 9900 μM). Furthermore, ε-PLL could also penetrate full thickness cartilage and showed a long-time retention in cartilage explants and mouse joint cavity. The results of in vitro and in vivo toxicity tests showed nearly no negative impact of ε-PLL (100 μg/mL) on chondrocytes or local tissue. Using kartogenin (KGN, a potential DMOAD) as a model drug, the effectiveness of ε-PLL to improve the drug bioavailability in a mouse OA model was proved. Together, these results suggest that ε-PLL can be used as an effective and safe CMC for effective DMOAD delivery to cartilage.

Aluminum Matrix Composites with Weak Particle Matrix Interfaces: Effective Elastic Properties Investigated Using Micromechanical Modeling.

The impact of weak particle-matrix interfaces in aluminum matrix composites (AMCs) on effective elastic properties was studied using micromechanical finite-element analysis. Both simplified unit cell representations (i.e., representative area or volume elements) and “real” microstructure-based unit cells were considered. It is demonstrated that a 2D unit cell representation provides accurate effective properties only for strong particle-matrix bond conditions, and underpredicts the effective properties (compared to 3D unit cell computations) for weak interfaces. The computations based on real microstructure of an Al–TiB2 composite fabricated using spark plasma sintering (SPS) show that, for weak interfaces, the effective elastic properties under tension are different from those obtained under compression. Computations show that differences are the result of the local stress and strain fields, and contact mechanics between particles and the matrix. Preliminary measurements of the effective elastic properties using the ultrasonic pulse-echo technique and compression experiments support the trends observed in computational analysis.

Bedding Plane Effects on Mechanical Behavior of Surrounding Rock in Mountain Tunneling

The layered rock showed the characteristics in Mountain tunnel, Yunnan. A series of uniaxial compression tests and variable angle shear tests were carried out, and the aim was to investigate the effect of the bedding on its mechanical parameters and failure modes. The test results show that the uniaxial compressive strength, elastic modulus, and Poisson's ratio of layered rock present a U-shaped distribution with the increase in bedding orientation from 0° to 90°. All of them have a maximum when the bedding orientation is 0° and a minimum when the bedding orientation is 45°. The failure modes of layered rock can be summarized into three types: the fracture tensile failure parallel to the weak plane of bedding; the shear slip failure along bedding weak plane; and tension-shear composite failure between bedding weak plane and matrix. Based on the testing data and analysis results, it can be concluded that the layered rock specimen with different bedding orientations is an important reason for the anisotropy of mechanical parameters and failure modes.

Hydrogeochemical facies and pollution status of groundwater resources of Owerri and environs, Southeastern Nigeria.

The aim of the study was to assess the status of groundwater quality of Owerri and environs, for drinking and irrigation purposes. Twenty-two (22) groundwater samples were collected and analyzed for both chemical and physical compositions. The result of the study showed that groundwater in the area is of good quality for drinking purposes, except for pH and Fe, which had higher concentrations in some areas. A weak correlation matrix within the sampled parameters of the groundwater was observed. Hydrogeochemical studies revealed that 91% of the samples are within the geochemical zone of 4 (strong acids (SO4 + Cl) exceed weak acids (CO3 + HCO3)), while 9% are of the geochemical zone of 3 (weak acids (CO3 + HCO3) exceed strong acids (SO4 + Cl)). The study shows an ionic trend of Cl- > Ca2+ > HCO3- > Na+ + K+ > Mg2+ > SO42- and hydrogeochemical facies of Na-Cl, Ca-Cl, Ca-CO3, Mg-Cl, and Mg-HCO3 of 45.5%, 36.4%, 4.5%, 4.5%, and 9.1% respectively. Chloro-alkaline values were negative except for B4 which was positive. The water quality index (WQI) revealed water quality status of excellent (4.5%), good (27.3%), poor (40.9%), and very poor (27.3%). Contamination factor (CF) reveals that the groundwater is slightly polluted while the pollution load index (PLI) revealed no noticeable pollution. Gibbs diagram revealed that the entire samples are within the rock dominance zone. Irrigation suitability studies showed that SAR of the groundwater was of excellent quality; %Na had good quality (27.3%), permissible quality (45.4%), and doubtful quality (27.3%); MH had 86.4% of the groundwater suitable, while 13.6% are not suitable; KR had suitable groundwater (59.1%) and unsuitable (40.9%); while the Wilcox diagram had 72.7% excellent water for irrigation and 27.3% permissible for irrigation. A routine check of groundwater in the study area is recommended.

In-situ shear strength testing of conglomerate formation for a large RCC dam (Koysha, Ethiopia)

Koysha Dam, located in the Southern Nations, Nationalities and Peoples’ Region of Ethiopia, is the fourth plant of the Gibe-Omo cascade comprising Gilgel Gibe (IP=200 MW), Gibe II (IP=420 MW) and Gibe III (1’870 MW) all in operation. The plant includes a 200 m high RCC gravity dam, a gated spillway on the left bank and an open-air powerhouse housing 6 Francis turbines fed by 2 steel penstocks crossing the dam body. The right abutment of the dam is partly founded on conglomerate, composed by a variable proportion of cobble and gravel sized basalt and rhyolite-trachyte sub-rounded elements surrounded by a weak matrix of fine sand and silt particles. The geotechnical characterization of such a complex material resulted in a very challenging task due to the substantial impracticality of collecting high quality, undisturbed and representative samples. Therefore, the mechanical behaviour of the conglomerate has been assessed by means of in-situ large scale shear tests carried out into a 70 m long inspection tunnel. The test results show that in the range of selected confinement pressures (0.3 to 1.0 MPa) the conglomerate exhibits a softening behaviour. Peak friction angle and cohesion are coherent with data and empirical models presented in the literature which indicate a strong correlation between volumetric block proportion and mechanical properties of the Block-In-Matrix (BIM) rock.

RLP-AGMC: Robust label propagation for saliency detection based on an adaptive graph with multiview connections

There have been remarkable improvements in the salient object detection in the recent years. During the past few years, graph-based saliency detection algorithms have been proposed and made advances. Nevertheless, most of the state-of-the-art graph-based approaches are usually designed with low-level features, misleading assumption, fixed predefined graph structure and weak affinity matrix, which determine that they are not robust enough to handle images with complex or cluttered background.In this paper, we propose a robust label propagation-based mechanism for salient object detection throughout an adaptive graph to tackle above issues. Low-level features as well as deep features are integrated into the proposed framework to measure the similarity between different nodes. In addition, a robust mechanism is presented to calculate seeds based on the distribution of salient regions, which can achieve desirable results even if the object is in contact with the image boundary and the image scene is complex. Then, an adaptive graph with multiview connections is constructed based on different cues to learn the graph affinity matrix, which can better capture the characteristics between spatially adjacent and distant regions. Finally, a novel RLP-AGMC model, i.e. robust label propagation throughout an adaptive graph with multiview connections, is put forward to calculate saliency maps in combination with the obtained seed vectors. Comprehensive experiments on six public datasets demonstrate the proposed method outperforms fourteen existing state-of-the-art methods in terms of various evaluation metrics.

Angular vortex phase diagram in YBa2Cu3O7 films with c-axis correlated pinning centers

High temperature superconductors (HTSCs) exhibit rich vortex phases under the influence of nanoscale pinning centers, and complicated configurations and behavior of vortices are realized by anisotropic vortex pinning, vortex interaction, and line tension. To understand the behavior and configurations of vortices, YBa2Cu3O7 films containing self-organized nanorods (BaSnO3, BaZrO3, BaHfO3) were prepared, and the critical current density and the resistivity were measured for varying angles between the nanorods (//c-axis) and the magnetic field (θ) in the temperatures of 65–90 K. The trapping angle of the strong nanorod (θ ts) determines the vortex phase boundary in the magnetic field lower than the matching field (B< B ϕ). While the large c-axis J c peak and the resistivity dip are observed for θ< θ ts due to the vortex accommodation on the nanorods, the vortices for θ> θ ts are pinned by the matrix uncorrelated defects and/or the ab-plane pinning centers. In the magnetic field higher than B ϕ(B> B ϕ), the weak matrix c-axis correlated defects such as twin boundaries accommodate vortices at the angles smaller than the trapping angle of the matrix c-axis correlated defect. Although the matrix c-axis correlated defects do not pin the matrix-vortices for the larger angles, the matrix-vortices are pinned by the vacant nanorod portions that appear due to the magnetic field tilt. This vortex retrapping results in the off-axis J c peak and the off-axis resistivity dip. Thus, the weak pinning by matrix defects, the cage potential, and the vortex retrapping as well as the strong nanorod pinning determine the angular vortex phase of the HTSCs containing c-axis correlated pinning centers.

Determination of 118 pesticide residues in dried wolfberry by gas chromatography-triple quadrupole mass spectrometry in dynamic multiple reaction monitoring mode

枸杞中丰富的营养物质深受广大消费者喜爱,但也极易受到病虫侵害,农药残留问题引起了人们的广泛关注。基质干扰是微量分析的一个难点,高灵敏度和高选择性的色谱-串联质谱技术是复杂基质中微量分析强有力的工具,动态扫描监测模式的优越性逐渐取代传统的多反应监测扫描模式,简便、快速、省时的QuEChERS前处理方法已被广泛应用于食品的农药残留检测中。采用改良QuEChERS法结合动态多反应监测模式(dMRM),建立了同时检测枸杞干果中118种农药残留的气相色谱-三重四极杆质谱分析方法。实验比较了不同加水量、提取溶剂、提取过程中温度提取条件,以及无水硫酸镁吸水剂、乙二胺-N-丙基硅烷化硅胶PSA、十八烷基硅烷键合硅胶C18净化填料添加量时农药的回收率,确定出最优前处理方法。结果表明,5 g样品经10 mL超纯水复水,用10 mL乙腈浸提,于-18 ℃冷冻10 min后,用缓冲体系盐包提取后,经800 mg无水硫酸镁、150 mg PSA、150 mg C18混合填料净化,基质匹配外标法定量。118种农药在一定范围内线性关系良好,相关系数R2≥0.9923,检出限和定量限分别为0.006~28.344 μg/kg和0.021~94.480 μg/kg, 4个添加水平的回收率为64.97%~126.21%, RSDs均小于19%(n=6)。基质效应考察结果表明,82%的农药呈现为基质增强效应,其他为基质抑制效应;9%的农药表现为强基质效应,其他为中等或弱基质效应;采用基质匹配标准曲线校正,可有效降低基质效应的影响。应用建立的方法测定10批枸杞样品,全部样品有农药检出,共检出农药22种。该方法操作简便快速,准确可靠,适用于枸杞干果中农药多残留的日常检测和快速筛查。

Effective rheology of a two-phase subduction shear zone: Insights from numerical simple shear experiments and implications for subduction zone interfaces

Inspired by exhumed subduction shear zones that commonly exhibit block-in-matrix characteristics (mélanges), we create synthetic models with different proportions of strong clasts within a weak matrix and compare them to natural mélange outcrops. Using 2D Finite Element visco-plastic numerical simulations in simple shear kinematic conditions, we determine the effective rheological parameters of such a two-phase medium, comprising blocks of basalt embedded within a wet quartzitic matrix. We treat our models and their structures as scale-independent and self-similar and upscale published field geometries to km-scale models, compatible with large-scale far-field observations. Like in the laboratory deformation experiments, we vary confining pressures, temperatures and strain rates to evaluate effective rheological estimates for a natural subduction interface. As expected, the block-in-matrix ratio affects deformation and strain localization, with the effective dislocation creep parameters (A, n, and Q) varying between the values of the strong and the weak phase, in cases where both materials deform by viscous creep. At conditions where the blocks are frictional and the matrix viscous, the mélange deforms effectively by dislocation creep but the locally frictional deformation of the blocks leads to higher stresses. This results in an effective value of the stress exponent, n, greater than that of both pure phases, as well as an effective rate-dependent viscosity lower than that of the weak phase. In combination with an appropriate evolution law for the block concentration of a mélange, our effective rheology parameters may be used in large scale geodynamic models as a proxy for a heterogeneous subduction interface.