Meso Structure Research Articles

Retrospective, Multi-center, Cohort Study Evaluating Clinical, Technical, Biological, and Esthetic Outcomes of Implant Supported Zirconia Single Crowns Cemented on Titanium-base Abutments: 7-year Mean Follow-up.

To retrospectively evaluate the long-term clinical, technical, biological, and esthetic outcomes of implant supported single zirconia crowns (ISCs) intraorally cemented to Ti-base hybrid-abutments up to 16 years after placement. A total of 63 ISCs (Xive S, Camlog Screw Line, Replace Select TC NP, Branemark MK II, and 3i Osseotite) were evaluated in 36 patients at two different centers. Original Ti-bases were selected and zirconia meso structures and zirconia crowns were designed using CAD/CAM software and then milled from partially stabilized zirconia blocks. After the meso structures were cemented extraorally onto the Ti-bases, the ceramic crowns were intraorally luted to the hybrid abutments. The Ti-base ISC restorations were followed up for up to 16 years, and their clinical, biological, and esthetic outcomes were recorded at distinct time points (T1; T2) at three-year intervals. 36 patients (18 men, 18 women) received 32 ISCs in the anterior region and 31 in the posterior region of the maxilla and mandible. The mean follow-up of the Ti-base ISCs was 6.93 ± 2.60 years. The mean follow-up of the implants amounted to 8.11 ± 3.26 years. No implants were lost during follow-up, resulting in a cumulative implant survival rate of 100%. Abutment screw loosening was observed in two ISCs after one year in service. The overall cumulative restorative survival rate of the Ti-base restorations reached thus 96.83%. At T2 follow-up 24% of the ISCs exhibited an increase in PD despite maintaining clinically healthy peri-implant tissue. An 11% increase in BOP and a 3.17% decrease in PI were recorded. Despite spectrophotometrically measured ΔE values indicating visible discoloration of some restorations and their peri-implant soft tissue, a low incidence of esthetic complications was observed with an average PES/WES score of ≥ 12. No correlation was found between PES (R = -0.25; p = 0.27) and WES (R = -0.18; p = 0.43) scores and digital shade determination. The results of the present retrospective, multicenter, cohort study indicate satisfactory clinical outcomes for intraorally cemented single zirconia crowns (ISCs) supported by Ti-base hybrid abutments. An overall esthetic superiority of Ti-base ISCs could not be confirmed.

Mesoscopic simulation of uniaxial compression fracture of concrete via the nonlocal macro–meso-scale consistent damage model

To capture the uniaxial compression fracture of concrete composite is still a great challenging problem. To this end, the newly proposed nonlocal macro–meso-scale consistent damage (NMMD) model is extended to simulate uniaxial compression fracture of concrete composites. In the NMMD model, a mesoscopic structure composed of material point pairs is attached to each material point. A decomposition scheme suitable for masonry-like materials is adopted to decompose the elongation quantity of point pairs. The topologic damage is defined as the weighted summation of mesoscopic damage in neighboring material point pairs driven by the decomposed elongation quantity. The physically-based energetic degradation function is employed to bridge the geometric discontinuity in solids and the energy dissipation, and thus the topologic damage is integrated into the framework of continuum damage mechanics. The Monte-Carlo method and two-phase random field model are employed to generate stochastic circular and irregular aggregates representing the meso structure of concrete, respectively. The interface transition zone is prescribed by reducing the critical value of interface point pairs. Numerical results indicate that both the crack patterns and stress–strain curves of the uniaxial compression experiments on concrete panels can be well captured by the proposed NMMD model without mesh size sensitivity. The influence of horizontal constraints on the top and bottom surfaces is investigated and shown to have an effect on the crack patterns, strength and deformation capability of the specimen. The necessity of decomposition is also illustrated.

Role OF KIT-6 on the fungicide and pesticide activities of zinc, copper and magnesium oxide nanoparticles prepared using Camellia sinensis extract (tea plant) through green synthesis

Nanoparticles have contributed to the society in many ways. They are of great use in various fields, such as semiconductors, medicine, cosmetics, agriculture, electronics, automobiles, catalysis, biosensors, paints etc. Magnesium, copper and zinc oxide nanoparticles have been synthesized from Camellia sinensis (tea) leaf extract in an environmentally friendly way. Surface morphology, phase identification and elemental analysis of the prepared metal oxide nanoparticles were carried out by SEM, powder XRD and EDAX analyses, respectively. The prepared metal oxide nanoparticles were tested for their fungicidal activity against the fungi pestalotiopsis theae, which causes grey blight disease, and pesticide activity against the pest oligonychus coffeae, which causes red spider mites disease in plants, particularly in tea plants. The effect of mesoporous KIT-6 on the pesticide activity of the prepared nanoparticles was also studied. The increased pesticidal property of the nanoparticles is correlated with the meso structures and properties of KIT-6. The bio efficacy of these metal oxide nanoparticles against the selected fungus and pest is discussed and compared in detail.

An extended universal morphological model for concrete mode‐I fracture: Parametric and case studies

AbstractThe purpose of this study is to develop a systematic meso‐level theoretical modeling approach for analyzing the mode‐I fracture failure behaviors of concrete. Firstly, the eXtended Universal Morphological Model (XUMM) is briefly reviewed. Secondly, a normalized analysis method for the evaluation of effects of properties and scales of meso structures on the performance of concrete is proposed based on the XUMM. Afterwards, parametric studies regarding the aggregate strength effect, the aggregate volume effect, the maximum aggregate size (MAS) effect, the tortuosity of mesoscopic crack, the roughness of fracture surface and the characteristic length are conducted. At last, a case study on the MAS effect based on experimental tests is provided to verify the applicability of the XUMM.

Effects of infill orientation and percentage on the magnetoactive properties of 3D printed magnetic elastomer structures

This work investigates how the internal meso structure of fused filament fabrication parts influence the magnetoactive properties of printed magnetic elastomer structures. Elastomers were made by adding 40wt% magnetite (Fe3O4) to a thermoplastic polyurethane (TPU) matrix. Magnetoactive testing was used to investigate how varying the infill structure affected the mechanical response of the structures within an applied magnetic field. Different infill percentages (40%, 60%, and 100%) and infill orientations (0, 45, and 90 degrees) were tested to account for different mechanical stiffnesses and internal geometries. Each sample was magnetoactively tested with three transverse magnetic field orientations (front, back and top). The samples were placed between two electromagnets, and the angle of deflection was recorded as a function of applied field. The maximum angles of deflection for the testing setup were reached when using lower infill percentages and having infill oriented parallel to the long axis of the sample and transverse to the magnetic field. Transverse fields applied parallel to the print plane (front/back sample orientations) demonstrated the most magnetoaction due to easier alignment of the long side of the sample with the field. This coupled with the 0-degree infill orientation having less crosslinking constraining the bending stiffness led to greater deflection. The magnetic anisotropy of the infill structure likely also contributed to the large response from certain samples. It was concluded that for this fixed base material, it is more important to 3D print structures with lower stiffnesses than more net magnetic particulate (more infill) to achieve the most magnetoaction.

Three-Dimensional Modeling of Spun-Bonded Nonwoven Meso-Structures.

As a type of fiber system, nonwoven fabric is ideal for solid-liquid separation and air filtration. With the wide application of nonwoven filter materials, it is crucial to explore the complex relationship between its meso structure and filtration performance. In this paper, we proposed a novel method for constructing the real meso-structure of spun-bonded nonwoven fabric using computer image processing technology based on the idea of a "point-line-body". Furthermore, the finite element method was adopted to predict filtration efficiencies based on the built 3D model. To verify the effectiveness of the constructed meso-structure and simulation model, filtration experiments were carried out on the fabric samples under different pollution particle sizes and inlet velocities. The experimental results show that the trends observed in the simulation results are consistent with those of the experimental results, with a relative error smaller than 10% for any individual datum.

A micro–macro constitutive model for rock considering breakage effects

The paper proposes a three-scale binary medium-based constitutive model on the basis of the meso structures and micro components to describe the elasto-plastic mechanical behavior of mudstone samples. Based on the breakage mechanism of geomaterials, mudstone samples are considered as two different materials (bonded and frictional elements) at mesoscales. From micro to meso scales, given the similar but different mineralogy composition and porosity of the bonded and frictional elements at microscale, as well as their separate mechanical characteristics, different homogenization methods are adopted to obtain their respective meso mechanical properties. At the mesoscale, in view of the unique meso structures and the continuous material transformation, the extended self-consistent scheme (SCS) is improved to be adaptable to elasto-plastic composites with varying meso components. With the consideration of the evolution form of the breakage ratio under the external loading being given based on the assumed strength distribution of the meso bonded elements, the mechanical relations between meso and macro scales are established. Finally, on the basis of the mean-field method and combined with the critical mechanical connections between different scales, the micro-meso-macro constitutive model for mudstone samples are proposed. The model validation shows that, with a few model parameters, the proposed model can well reflect the stress and deformation features of mudstone samples with complex micro-components.

Three-dimensional numerical simulation study of pre-cracked shale based on CT technology

Due to the heterogeneity of rock media, it is difficult to truly reflect its internal three-dimensional microstructure in physical tests or numerical simulation. In this study, CT scanning technology and numerical image processing technology are used, and the finite element software RFPA-3D is used to establish a three-dimensional non-uniform numerical model that can reflect the meso structure of rock mass. In order to study the fracture mechanism of shale with prefabricated fractures, seven groups of three-dimensional numerical models with prefabricated fractures from different angles were constructed, and Brazilian fracturing numerical simulation tests were carried out. The results show that method of reconstructing 3D numerical models by CT scanning is feasible and provides a viable method for in-depth study of the micromechanics of shale. Prefabricated fractures and quartz minerals have significant effects on the tensile strength of shale, and both will weaken the destructive strength of shale specimens. The damage modes of Brazilian disc specimens containing prefabricated fissures can be divided into four categories. The damage process is divided into budding, plateauing and surge periods by acoustic emission. The crack initiation angle of the prefabricated fissure tip increases with increasing fissure angle, and the MTS criterion can be used as a basis for judging prefabricated fissure initiation. The results of the study are important guidance for the fracture initiation mechanism and fracture expansion law of the fractured layer containing natural fractures in the hydraulic fracturing process.

Patriotism Ideology in Anthology 100 Monologues by Putu Wijaya

This study aims to determine: (1) the form of patriotism ideology in Putu Wijaya's 100 Monologues anthology, (2) the meaning of patriotism ideology in Putu Wijaya's 100 Monologues anthology, and (3) representation of patriotism ideology which is realized at the microstructure level, meso, and macro in Putu Wijaya's 100 Monologue anthology. This type of research is descriptive analytical research. The primary data sources in this study were Putu Wijaya's monologues, namely (1) "Apakah Kita sudah Merdeka??” (2) "Demokrasi", and (3) "Nationality". The results of this study are, first, the form of patriotism includes appreciating the services of heroes, and striving to advance Indonesia. The two meanings of the ideology of patriotism are, among others, respect for Indonesian heroes, and being willing to sacrifice. Third, in the micro structure, metaphorical and hyperbolic figure of speech are found, then in the meso structure there is an intertextual element referring to texts such as the text of the proclamation of independence and previous literary works, the interdiscursive element, which refers to the conversation of previous figures represented in the same sentence or in the form of character's attitude. In the ideological macro structure found the ideology of patriotism. The next macro structure is power, in the monologue “Apakah Kita sudah Merdeka?” the element of power lies in the grandfather character, the monologue "Demokrasi" the element of power lies in the factory director, and the monologue "nationality" the element of power lies in the grandmother figure.

Network Society and Enterprise Management Reforms: A Fieldwork Study in Daoxiangcun Group Co. Ltd.

In a network society, the fast-changing economic situation brings about considerable challenges to traditional enterprises, especially for a “time-honored” enterprise like Daoxiangcun Group. It is an interesting academic topic for scholars to portray the ways in which these time-honored enterprises have achieved tradition-modernization transformation via the internet technology. This paper, by taking Daoxiangcun Group as a case study, makes an anthropological fieldwork research and analyzes the changes in the management of Daoxiangcun Group at four levels: network society as the macro structure, the baking industry as the meso structure, the company’s organizational structure and business processes as the micro structure. It is found that the tradition-modernization reforms reflect the pattern of “from outside to inside” to “from inside to outside”, and the pattern of "from top to bottom” to “from bottom to top”.

Youth transition, agricultural education and employment in Uganda: freeing individual agency

ABSTRACT The reality of the troubles young people encounter in navigating confining social and institutional settings to become productive workers and flourishing citizens in sub-Saharan African countries like Uganda continues to attract all sorts of theoretical and social policy assumptions. One such prominent assumption is the idea that increased young people’s participation in agricultural education and work has the potential to stem escalating youth unemployment. The related narrative that young people are less keen to plunge their learning and work life in agriculture owing to its low social status poses a huge education and labour policy dilemma across SSA and similar contexts. Amid this dilemma are narratives, which seem to underplay the influential social arrangements that structure the education–work trajectories of young people and the perceptions and practice of micro-social actors in the agriculture education and labour markets. Questionable narratives that often attempt to frame young people as authors of their own troubled work transitions abound sections of social policy and development discourse. Moreover, mainstream research and evaluative studies in Uganda and similar contexts do have a traditional focus on macro and meso structures with limited methodological interest into the voices and experiences of frontline social actors. Accordingly, this qualitative study is an in-depth examination of personal and contextual influences on young people’s agricultural education-employment transitions; and exploration of how to improve transition processes for optimising learning and labour market outcomes. The findings reveal unprecedented resilience and volitions of young people to advance their education–work trajectories despite the structural barriers. The study showed a reasonable degree of enthusiasm amongst some micro-social actors in supporting young people on their life transitions though often constrained by confining social and institutional arrangements. The study yielded robust evidence into the difficulties to cause AET system improvements for better student outcomes but also delivered incredible insights for making change possible. Freeing and nurturing the individual agency of Ugandan young people to choose and pursue agricultural education and work aspirations along the constricting pathways enacted as part of societal canalisation is among the core elements of this thesis. The agency freedom and professional autonomy of frontline social actors, especially agricultural educators to enable them to practise craftsmanship, democracy and associated transformative approaches for better preparation of young people to navigate their education and career trajectories is equally a core argument of this thesis.

Incremental shear strain chain: a mesoscale concept for slip lines in 2D granular materials

Constitutive behaviors of granular materials are driven by both particle interactions and geometric arrangements of contact network. To bridge the gap between the grain scale and the sample scale, the mesoscale is of great importance as it corresponds to the smallest scale at which geometrical effect can be accounted for. Meso shear structures (sometimes called microbands) have been observed frequently on incremental strain maps in granular materials under shearing, while the Rudnicki and Rice localization criterion for shear band is not fulfilled yet. These meso structures are thin, quasi-linear and they involve a few grains as well as their surrounding voids. This paper introduces the concept of “incremental shear strain chain” (simply called “shear chain”) to provide a specific quantitative definition of such mesostructures. “Shear chains” are defined based on incremental deviatoric strain fields in 2D biaxial simulations. Particular attention is paid to demonstrate that the shear chain orientation is a material scale property, insensitive to boundary conditions, loading paths and sample densities. Since shear chains are shown to be closely related to sliding mechanisms, they can stand for a mesoscale definition of the concept of slip lines as defined in the standard elasto-plasticity theory.

Improvement effect of a double-level phase change material on compressive strengths of Portland cementitious materials after elevated temperatures

In this investigation, a specially prepared double-level phase change material (DL-PCM) was introduced to ordinary Portland cement(OPC) to improve compressive strengths after elevated temperatures. Solid-liquid phase transition characteristics of DL-PCM and changes in compressive strength, water absorption, mass, as well as meso structures and mineral compositions of OPC after elevated temperatures were determined to clarify improvement mechanisms of DL-PCM on compressive strengths of OPC after elevated temperatures. Results show after 500 °C and 600 °C exposures, compressive strengths of OPC added with DL-PCM were basically equal to or a little higher than those at room temperatures. Cracks in DL-PCM introduced OPC matrix and water absorptions were significantly reduced. During the heating and cooling process, DL-PCM experienced solid-liquid-solid phase transitions, forming hard densifed solids to fill cracks and pores, significantly improving integrity of OPC matrix. Consequently, compressive strengths of DL-PCM introduced OPC were significantly increased compared to those without DL-PCM after elevated temperatures.

An FFT‐based Galerkin method for the effective permeability of porous material

AbstractA numerical scheme which is a combination of FFT and Galerkin methods is proposed for calculating the effective permeability of periodic porous material. First, a periodic stress field whose divergence is equal to the subtraction of body force from prescribed pressure gradient is introduced to reformulate the governing equations. Then, an auxiliary problem is established to replace the prescribed pressure gradient with the resulting initial prescribed stress. An FFT‐based Galerkin method of stress control type, the associated projection operator for zero divergence condition and the treatment of composite pixels/voxels are presented for solving the viscous flow in periodic porous material. Finally, numerical examples of viscous flows in 2D parallel fissured medium, 2D medium with regularly packed squares, 2D medium with regularly packed and rotated squares, 3D medium with regularly packed ellipsoids, and 3D medium with randomly packed ellipsoids are implemented. Numerical results calculated by FFT‐based Galerkin method agree well with analytical solutions and finite element results. The proposed FFT‐based Galerkin method is effective for predicting the macro permeability of porous material with complex meso structures.

When Helping Hurts: A Zemiological Analysis of a Child Protection Intervention in Adolescence—Implications for a Critical Child Protection Studies

This paper presents data from a three-year, mixed methods study into the rate and impact of ‘relocation’ as a response to extra-familial harm in adolescence by children’s social care teams. Participatory approaches to research design, data collection and analysis are used to gain insights from young people, parents/carers and professionals about the impact of relocations on safety. Professionals and young people report a range of harms implicated in the use of relocations, whilst sharing that the intervention often increases safety. Data are analysed zemiologically to understand this ambivalence, connecting micro accounts of harm with meso, institutional and macro structures that determine child protection intervention. Zemiology is put forward as a promising approach for a Critical Child Protection Studies.

Micro-CFD modelling of ultrafiltration bio-fouling

ABSTRACT Concentration polarisation on the membrane process is a vast area of interest. The macroscopic characterisation of fouling structure formation occurring during the Ultra-Filtration (UF) of Bovine Serum Albumin (BSA) was studied in this work. A twisted Monte-Carlo (MC)/Computational-Fluid-Dynamic (CFD) approach was developed to calculate macroscopic fluid-dynamic proprieties. Different fluid-dynamic simulations were performed based on the knowledge acquired by an MC analysis that provided boxes of adsorbed molecules (i.e., 3D proteins meso configurations on the UF membranes surface). These represented the deposit layers formed at different distances from the membrane. The 3D meso structure were imported into a bespoke simulation environment, and several meshes were created to perform micro-fluid dynamic calculations (m-FD). From these simulations, a set of macroscopic parameters was calculated. The resistance to the flow of deposit layers accumulated on the membrane surface, , usually estimated by experimental methods, was computed starting from the ab-initio knowledge acquired at sub-nanoscopic scale. Therefore, this work provides a multi-scale description of a complex phenomenon such as that of protein fouling during a UF filtration starting from a sub-nanometric scale.

Influences and Effects on Scaling the Pressure Stiffness of Additively Manufactured Meso Structures

AbstractAM-meso structures offer a high potential for adapted properties combined with lightweight design. To utilize the potential a purposeful design of the meso structures is required. Therefore, this contribution presents an approach for modelling their properties depending on design parameters by scaling relationships. The relationships are investigated based on grey box and axiomatic models of elementary cells. Exemplary the pressure stiffness is determined using FEM in comparison to an analytical approximation. The comparison reveals effects and influences occurring within the elementary cell.

Identification of multi-scale homogeneity of blended cement concrete: macro performance, micro and meso structure

Identification of multi-scale homogeneity of blended cement concrete: macro performance, micro and meso structure

Experimental device to measure the ionic conductivity anisotropy in liquid crystal hydrogel based in [EMIM] alkyl sulfate Ionic Liquids

We have built an experimental device with the aim to measure the expected electrical conductivity anisotropy in a liquid crystal, obtained from the gelation of the ionic liquid 1-ethyl-3-methyl imidazolium decyl sulfate, [EMIM][DSO4]. This ionic liquid has the particularity that it transits to a semi-solid gel state at room temperature when it contains water, naturally adsorbed from the environment until a balance is reached between the concentration of water in the IL and the atmospheric humidity grade. The quantity of water adsorbed to form the hydrogel at room temperature varies from about 5 to 30 wt%, each composition giving place to different smectic phases. In the gel state, the ionic liquid ions and the water molecules self-organize into micro-sized mesophases that resemble the structures of a liquid crystal. Our device is a closed 2D sample holder (with sides 150 times longer than its thickness), with a single narrow window open to the atmosphere, and four copper contacts on the sides. The dried ionic liquid is tempered at 40 °C to increase its fluidity when injected into the cavity, and then, it can only adsorb water through the narrow opening. Thus, water adsorption is unidirectional and slow, so the transition of the IL to the gel phase happens progressively. A metastable giant mesophase appears as an orientated macrodomain in the form of a striped pattern. In this state, we measure the electrical conductivity of the confined film in directions parallel and perpendicular to the observed strips, finding a difference of up to 26% between both values of the conductivity. If the sample freezes (below 10 °C) or it liquefies (above 50 °C) the meso structure is broken and the observed anisotropy destroyed. We can return the sample to gel state by varying the temperature, but the ordered macroscopic state is no longer recovered. This research must give clues to solve the charge transport mechanism quiz in ionic liquids and semi-solid coductors.

A scattering function for correlated lamellae

Melt crystallized polymers display an emergent, multi-hierarchical, ordered structure made up of stacked lamellar single crystals that form fibrous or other meso structures which, in turn, form macroscopic crystallites. A dominant feature of small-angle scattering from these complex assemblies is a correlation peak associated with the stacking period. A new model-based function is proposed for small-angle scattering data from such correlated lamellar multi-hierarchical structures. Generally, routine use of scattering data has been limited to a 1-d analysis to determine the long period from Lorentz corrected data (I(q)q2 versus q). Fourier transforms of the data are sometimes used to determine the 1-d pairwise correlation function for the electron-density distribution which has been further analyzed in terms of the structure of these materials. A simple 1-d fitting model limited to infinite width 2-d sheets was introduced by Hermans (1944; Hosemann, 1950) [1,2] in the 1940s with some success. A new approach, the Unified Born-Green Function (UBG), is proposed that uses the Unified Function as adapted to correlated lamellar structures and incorporates a Born-Green description of one-dimensional correlations. The UBG fit allows quantification of the average lamellar aspect ratio, the local degree of crystallinity within a stack, quantification of the stacking versus non-stacking amorphous, and two types of disorder in addition to the stacking period and lamellar thickness. UBG can account for higher levels of structure such as crystalline domains in block copolymers and convoluted lamellar structure. The UBG fit is compared to the Hermans (1944; Hosemann, 1950) [1,2] and a hybrid-Hermans function. Fits to data sets from a wide range of polyethylene are shown ranging from molecular weight standard samples that are isothermally crystallized, to commercial HDPE quenched from the melt and a metallocene blown film sample. Several other examples from the literature are explored. It is shown that the Unified fit allows for new understanding of the impact of thermal and mechanical history, chain structure, fillers, nucleating agents, and additives on the crystalline structure and the resulting physical properties. Limitations of the UBG approach are noted.