3D Block Research Articles

Numerical study of effective heat conductivities of foams by coupled conduction and radiation

Effective thermal conductivities (ETC) under vacuum were computed numerically on 3D blocks of open-cell foams either obtained by X-ray tomography or generated by Computer-Aided Design (CAD) with ideal geometries. For the first time a Monte-Carlo/Random Walk code accounting for the coupling of conduction in the solid phase and of radiation in the pore space has been used. The whole range of conduction/radiation ratio, parameterized by a Nusselt number, has been scanned; a law relating the ETC to this parameter has been obtained. In all cases the conductive and radiative contributions are additive. The slope of the radiative contribution to the ETC is found to display a distinct behavior, depending on whether radiation or conduction dominates. The low-temperature regime has an emissivity-dependent ETC slope, while the high-temperature regime does not. The critical ratio between both regimes is related to the ratio between cell and strut diameters. In all cases, it is found that the ETC anisotropy decreases with temperature. Closing some windows enhances conduction parallel to the closing walls and reduces radiation perpendicular to them. This effect is shown to influence the ETC eigendirections in actual media.

RASTERIZATION AND VOXELIZATION OF TWO- AND THREE-DIMENSIONAL SPACE PARTITIONINGS

Abstract. The paper presents a very straightforward and effective algorithm to convert a space partitioning, made up of polyhedral objects, into a 3D block of voxels, which is fully occupied, i.e. in which every voxel has a value. In addition to walls, floors, etc. there are 'air' voxels, which in turn may be distinguished as indoor and outdoor air. The method is a 3D extension of a 2D polygon-to-raster conversion algorithm. The input of the algorithm is a set of non-overlapping, closed polyhedra, which can be nested or touching. The air volume is not necessarily represented explicitly as a polyhedron (it can be treated as 'background', leading to the 'default' voxel value). The approach consists of two stages, the first being object (boundary) based, the second scan-line based. In addition to planar faces, other primitives, such as ellipsoids, can be accommodated in the first stage without affecting the second.

RASTERIZATION AND VOXELIZATION OF TWO- AND THREE-DIMENSIONAL SPACE PARTITIONINGS

The paper presents a very straightforward and effective algorithm to convert a space partitioning, made up of polyhedral objects, into a 3D block of voxels, which is fully occupied, i.e. in which every voxel has a value. In addition to walls, floors, etc. there are 'air' voxels, which in turn may be distinguished as indoor and outdoor air. The method is a 3D extension of a 2D polygon-to-raster conversion algorithm. The input of the algorithm is a set of non-overlapping, closed polyhedra, which can be nested or touching. The air volume is not necessarily represented explicitly as a polyhedron (it can be treated as 'background', leading to the 'default' voxel value). The approach consists of two stages, the first being object (boundary) based, the second scan-line based. In addition to planar faces, other primitives, such as ellipsoids, can be accommodated in the first stage without affecting the second.

Interactive virtual try-on based three-dimensional garment block design for disabled people of scoliosis type

This paper introduces a co-design-based method for generating two-dimensional (2D) block patterns for physically disabled people with scoliosis, using three-dimensional (3D) virtual technology. A parameterization process is first performed on a scanned 3D body for creating a digitalized model of the human body, permitting simulation of the consumer's morphological shape with atypical physical deformations. Feature points of the human body for designing a garment block are discussed and classified with wearing ease for obtaining a desired fit effect based on the parameterized model. A basic garment block wire-frame aligned with body features is then established based on the defined feature points of the human body. Based on the deformed wireframe, a 3D expandable garment block is modeled. Customized 2D and 3D virtual garment prototyping tools are applied to create customized garment products based on the general concept of co-design by running the sequence Design–Display–Evaluation–Adjustment using the garment design process and design knowledge, which have already been applied to normal body shapes successfully. Through this process, the classical 2D garment design knowledge, especially 2D pattern design rules, will be modified according to the virtual garment evaluation procedure. The proposed method is validated and compared with the conventional block patternmaking methods in the virtual environment. The experimental results show that the proposed method is easier to implement and can generate garment patterns with satisfactory fit. Furthermore, the method can be used to create fit-ensured mass-customized apparel products (the top body type) for disabled people with scoliosis.

Integrating artificial neural networks and geostatistics for optimum 3D geological block modeling in mineral reserve estimation: A case study

In this research, a method called ANNMG is presented to integrate Artificial Neural Networks and Geostatistics for optimum mineral reserve evaluation. The word ANNMG simply means Artificial Neural Network Model integrated with Geostatiscs. In this procedure, the Artificial Neural Network was trained, tested and validated using assay values obtained from exploratory drillholes. Next, the validated model was used to generalize mineral grades at known and unknown sampled locations inside the drilling region respectively. Finally, the reproduced and generalized assay values were combined and fed to geostatistics in order to develop a geological 3D block model. The regression analysis revealed that the predicted sample grades were in close proximity to the actual sample grades. The generalized grades from the ANNMG show that this process could be used to complement exploration activities thereby reducing drilling requirement. It could also be an effective mineral reserve evaluation method that could produce optimum block model for mine design.

Comparison of multislice breath-hold and 3D respiratory triggered T1 ρ imaging of liver in healthy volunteers and liver cirrhosis patients in 3.0 T MRI.

To compare visual quality and quantitative measurements of multislice (MS) breath-hold and 3D respiratory-triggered T1 ρ sequences. T1 ρ scans including MS BLOCK T1 ρ, MS HS8 T1 ρ, and 3D BLOCK T1 ρ were performed on 40 healthy volunteers and 17 liver cirrhosis patients on 3.0T magnetic resonance imaging (MRI). The MS breath-hold methods scanned three slices while the 3D method covered 26 slices. Visual scores of image quality, T1 ρ measurements of the three sequences, and T1 ρ values of healthy volunteers and cirrhosis patients were compared using parametric tests. Average visual scores for volunteers and patients of the three sequences were 3.19 and 2.82 for MS BLOCK T1 ρ; 3.71 and 3.59 for MS HS8 T1 ρ; 3.29 and 3.59 for 3D BLOCK T1 ρ, respectively. Difference of visual scores among the three groups was significant (P < 0.001). Differences in T1 ρ values among the three methods were significant (P < 0.001). Difference of T1 ρ between MS BLOCK T1 ρ and 3D BLOCK T1 ρ was not significant (volunteer: P = 0.82, patient: 0.92) while the difference of T1 ρ between MS BLOCK T1 ρ and MS HS8 T1 ρ, MS HS8 T1 ρ and 3D BLOCK T1 ρ was significant in both volunteers and patients (P < 0.01). Differences of T1 ρ between healthy volunteers and patients were all significant in three T1 ρ sequences (P = 0.04, 0.004, 0.03). Of the tested sequences, the image quality of MS HS8 T1 ρ was best, but 3D BLOCK T1 ρ with respiratory triggering should also be considered as an alternative sequence for clinical diagnosis of liver cirrhosis due to its superior coverage. J. MAGN. RESON. IMAGING 2016;44:906-913.

Comparative analyzes among electrical resistivity tomography arrays in the characterization of flow structure in free aquifer

This paper makes a comparative analysis between the Dipole-dipole, Wenner and Schlumberger arrays through electric resistivity tomography (ERT), about the sensitivity and resolution in the spatial characterization of infiltrating pollutants in septic tank and cone of depression in supply well, both contained in unconfined aquifer. Data acquisition consisted of electrical resistivity rea-dings using five parallel lines with 105m long, electrode spacing and lines of 5m. The data from each line were subjected to 2D inversion and then interpolated to generate 3D blocks, which were extracted from a fixed resistivity isosurface (620 W.m), which enabled the modeling of volumes related to the flow structures. The results for the Dipole-dipole array allowed the modeling of the cylindrical structure associated to the supply well, and an isosurface deformation associated to the septic tank, but did not allow the modeling of the plume. The data for the Schlumberger array cannot allow for the cone recognition, but resulted in a drop shape model, associated to the septic tank and similar to a contamination plume. The Wenner array resulted in a model with structu-re in elongated keel format associated to the cone of depression, and another that is similar to the drop shape model, also associated to the septic tank. The comparative analysis shows that the Dipole-dipole array is recommended in works of modeling vertically integrated three-dimensional structures of high resistivity in the saturated zone. The Wenner and Schlumberger arrays are recommended for modeling vertically integrated three-dimensional structures of low resistivity in unsaturated zone, with emphasis on the Schlumberger array.

Controlled 3D Carbon Nanotube Structures by Plasma Welding

3D interconnected carbon nanotubes (CNTs) are synthesized using an industrially scalable spark plasma technique. At high electric field and elevated temperature under sufficient stress the nanotubes are welded together to form a solid block. The detailed spectroscopic and microscopic analyses show successful welding of the CNTs and formation of interconnected networks. The mechanical characteristics of the 3D CNT block show a high stiffness and yield strength. A full atomistic molecular dynamics simulation elucidates the CNT welding mechanism. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Competition Between Effects of Pore Sizes and Annealing Solvents on the Morphology Manipulation of 3D Block Copolymer Nanostructures Using Anodic Aluminum Oxide Templates

Competition Between Effects of Pore Sizes and Annealing Solvents on the Morphology Manipulation of 3D Block Copolymer Nanostructures Using Anodic Aluminum Oxide Templates

Anomaly detection based on spatio-temporal sparse representation and visual attention analysis

In this paper, we proposed a unified framework for anomaly detection and localization in crowed scenes. For each video frame, we extract the spatio-temporal sparse features of 3D blocks and generat...

Improving children's cognitive modifiability by dynamic assessment in 3D Immersive Virtual Reality environments

Increasing evidence reveals the efficacy of dynamic assessment (DA) procedure in providing rich and reliable feedback regarding children's cognitive modifiability. The DA procedure included four phases: pre-teaching test, teaching, post-teaching and transfer test two weeks after teaching. The teaching phase includes mediated learning experience strategies. Children's cognitive modifiability was examined by pre- to post-teaching improvement and by the transfer test. Children in Grades 1 and 2 (n = 117) were randomly assigned into three experimental groups and one control group. Each of the experimental groups was given the teaching phase in a different modality: 3D Immersive Virtual Reality (IVR, n = 36), 2D (n = 36), and tangible blocks (TB, n = 24). The control group (n = 21) was not given teaching phase. The teaching phase included strategies of solving problems from the Analogies Subtest of the Cognitive Modifiability Battery (CMB). Pre- and post-teaching CMB Analogies tests were administered to all groups followed by CMB Transfer Analogies two weeks later. The findings indicate that the 2D and TB groups showed higher cognitive modifiability than the control group. Also, the findings indicate that teaching in a 3D IVR environment contributed to the children's cognitive modifiability more than in the other groups in the CMB Transfer Analogies. The findings are discussed in relation to the unique enhancing characteristics of the 3D IVR condition combined with the applied mediation strategies.

3D rigid block micro-modelling of a full-scale unreinforced brick masonry building using mathematical programming

In this paper, we present a three-dimensional limit equilibrium analysis of an unreinforced brick masonry building. The structure under investigation is a one-room one-floor building that has been selected from a full-scale test carried out within the framework of a joint USA-Pakistan research project. The structural model of the building is an assemblage of rigid blocks, which interact through no-tension contact surfaces with Coulomb friction. A micro-modelling approach is adopted where each masonry unit is modelled as a rigid body. The underlying limit analysis formulation is based on the concave contact model, with contact forces located at the vertices of the interfaces. Iterative calculations are carried out to deal with the non-associative friction behaviour. The numerical analysis is carried out with the aid of a computer program that provides as output the failure load and the collapse mechanism. The comparison with experimental outcomes shows that the adopted formulation is capable to predict the actual behaviour of 3D masonry structures with a reasonable computational effort.

3D rigid block micro-modelling of a full-scale unreinforced brick masonry building using mathematical programming

In this paper, we present a three-dimensional limit equilibrium analysis of an unreinforced brick masonry building. The structure under investigation is a one-room one-floor building that has been selected from a full-scale test carried out within the framework of a joint USA-Pakistan research project. The structural model of the building is an assemblage of rigid blocks, which interact through no-tension contact surfaces with Coulomb friction. A micro-modelling approach is adopted where each masonry unit is modelled as a rigid body. The underlying limit analysis formulation is based on the concave contact model, with contact forces located at the vertices of the interfaces. Iterative calculations are carried out to deal with the non-associative friction behaviour. The numerical analysis is carried out with the aid of a computer program that provides as output the failure load and the collapse mechanism. The comparison with experimental outcomes shows that the adopted formulation is capable to predict the actual behaviour of 3D masonry structures with a reasonable computational effort.

Hybrid OpenMP/MPI programs for solving the time-dependent Gross–Pitaevskii equation in a fully anisotropic trap

We present hybrid OpenMP/MPI (Open Multi-Processing/Message Passing Interface) parallelized versions of earlier published C programs (D. Vudragovic et al., Comput. Phys. Commun. 183, 2021 (2012)) for calculating both stationary and non-stationary solutions of the time-dependent Gross-Pitaevskii (GP) equation in three spatial dimensions. The GP equation describes the properties of dilute Bose-Einstein condensates at ultra-cold temperatures. Hybrid versions of programs use the same algorithms as the C ones, involving real- and imaginary-time propagation based on a split-step Crank-Nicolson method, but consider only a fully-anisotropic three-dimensional GP equation, where algorithmic complexity for large grid sizes necessitates parallelization in order to reduce execution time and/or memory requirements per node. Since distributed memory approach is required to address the latter, we combine MPI programing paradigm with existing OpenMP codes, thus creating fully flexible parallelism within a combined distributed/shared memory model, suitable for different modern computer architectures. The two presented C/OpenMP/MPI programs for real- and imaginary-time propagation are optimized and accompanied by a customizable makefile. We present typical scalability results for the provided OpenMP/MPI codes and demonstrate almost linear speedup until inter-process communication time starts to dominate over calculation time per iteration. Such a scalability study is necessary for large grid sizes in order to determine optimal number of MPI nodes and OpenMP threads per node.

Quantification of modification of ground motion due to urbanization in a 3D basin using viscoelastic finite-difference modelling

This paper presents the quantification of modification of ground motion due to urbanization in a 3D basin as compared to the free-field motion. The complex interaction effects of basin and city on the ground motion during an earthquake are termed as site–city interaction (SCI) effect in this paper. The cities were developed using 3D building blocks of sixteen-storey (city 1) and eight-storey (city 2) buildings. The analysis, in terms of ground motion perturbation and % reduction in average spectral amplification (ASA) and kinetic energy (KE) as compared to free-field motion, of the simulated responses of the various 3D basin-city models revealed very large role of basin shape, sediment layering, city shape, building type in the city and city density in the SCI effects on the free-field motion. The first spectral amplification peak frequency at the top of the buildings corroborates with the combined fundamental frequency of the building block and sediment deposit in basin. The obtained very large amplification of the order of 49 at the top of a single B8 building may be due to the closeness of the fundamental frequency of the combined basin-building system with the fundamental frequency of the basin and the dominant frequency in the input signal. This was also responsible for the larger % reduction in ASA and KE in city 2 (B8 buildings) as compared to the city 1 (B16 buildings). Based on the analysis of the obtained results, it is concluded that if a city is developed considering into account the building type, city shape and city density as per the basin shape and sediment parameters can be highly beneficial in reducing the earthquake disaster.

Surface-Confined Supramolecular Self-Assembly of Molecular Nanocranes for Chemically Lifting and Positioning C60 above a Conducting Substrate.

2D supramolecular self-assembly is a good way to form well-defined nanostructures on various substrates. One of the current challenges is to extend this approach to 3D functional building blocks. Here, we address this issue by providing a strategy for the controlled lifting and positioning of functional units above a graphitic substrate. This is the first time that multistory cyclophane-based 3D tectons incorporating C60 units have been designed and synthesized. Molecular modelling provides a description of the 3D geometries and evidences the flexible character of the building blocks. Despite this later feature, the supramolecular self-assembly of Janus tectons on HOPG yields well-ordered adlayers incorporating C60 arrays at well-defined mean distances from the surface. As our approach is not limited to C60 , the results reported here open-up possibilities for applications where the topological and electronic interactions between the substrate and the functional unit are of prime importance.

Empirical Assessment of the Mean Block Volume of Rock Masses Intersected by Four Joint Sets

The estimation of a representative value for the rock block volume (Vb) is of huge interest in rock engineering in regards to rock mass characterization purposes. However, while mathematical relationships to precisely estimate this parameter from the spacing of joints can be found in literature for rock masses intersected by three dominant joint sets, corresponding relationships do not actually exist when more than three sets occur. In these cases, a consistent assessment of Vb can only be achieved by directly measuring the dimensions of several representative natural rock blocks in the field or by means of more sophisticated 3D numerical modeling approaches. However, Palmstrom’s empirical relationship based on the volumetric joint count Jv and on a block shape factor β is commonly used in the practice, although strictly valid only for rock masses intersected by three joint sets. Starting from these considerations, the present paper is primarily intended to investigate the reliability of a set of empirical relationships linking the block volume with the indexes most commonly used to characterize the degree of jointing in a rock mass (i.e. the Jv and the mean value of the joint set spacings) specifically applicable to rock masses intersected by four sets of persistent discontinuities. Based on the analysis of artificial 3D block assemblies generated using the software AutoCAD, the most accurate best-fit regression has been found between the mean block volume (\(V_{{{\text{b}}_{\text{m}} }}\)) of tested rock mass samples and the geometric mean value of the spacings of the joint sets delimiting blocks; thus, indicating this mean value as a promising parameter for the preliminary characterization of the block size. Tests on field outcrops have demonstrated that the proposed empirical methodology has the potential of predicting the mean block volume of multiple-set jointed rock masses with an acceptable accuracy for common uses in most practical rock engineering applications.

Electrical resisitivity to detect zones of biogas accumulation in a landfill

Biogas produced in sanitary landfills consists in a potential source, formed by degradation of organic matter, this gas is constituted by CH 4 , CO 2 and water vapor. Sanitary landfills represent important depository of organic matter with great energetic potential in Brazil, although presently with inexpressive use. Estimates for production or maintenance of productive rates of CH 4 represent one of the main difficulties of technical order to the planning and continuity of collection systems for rational consumption of this resource. Electrical resistivity measurements are routinuously used in profiling oil wells for the determination of levels with accumulations of oil and gas, facing the contrast among fluids and rocks. This paper aims to evaluate eventual relationship among biogas flow quantified in surface drains of a waste cell in landfill, with characteristic patterns of in depth electrical resistivity. The integration of Electrical Resistivity Tomography (ERT) lines allowed for the generation of 3D blocks and a clear distinction among zones of high biogas production, quantified in surface drains, with areas of high resistivity in depth. The results suggest the possibility of use of the method in studies to place drains in areas promising to the collection of biogas for energetic generation in sanitary landfill.

Electrical resisitivity to detect zones of biogas accumulation in a landfill

Biogas produced in sanitary landfills consists in a potential source, formed by degradation of organic matter, this gas is constituted by CH4, CO2 and water vapor. Sanitary landfills represent important depository of organic matter with great energetic potential in Brazil, although presently with inexpressive use. Estimates for production or maintenance of productive rates of CH4 represent one of the main difficulties of technical order to the planning and continuity of collection systems for rational consumption of this resource. Electrical resistivity measurements are routinuously used in profiling oil wells for the determination of levels with accumulations of oil and gas, facing the contrast among fluids and rocks. This paper aims to evaluate eventual relationship among biogas flow quantified in surface drains of a waste cell in landfill, with characteristic patterns of in depth electrical resistivity. The integration of Electrical Resistivity Tomography (ERT) lines allowed for the generation of 3D blocks and a clear distinction among zones of high biogas production, quantified in surface drains, with areas of high resistivity in depth. The results suggest the possibility of use of the method in studies to place drains in areas promising to the collection of biogas for energetic generation in sanitary landfill.

Ring Closure To Form Metal Chelates in 3D Fragment-Based de Novo Design.

We describe a method for the design of multicyclic compounds from three-dimensional (3D) molecular fragments. The 3D building blocks are assembled in a controlled fashion, and closable chains of such fragments are identified. Next, the ring-closing conformations of such formally closable chains are identified, and the 3D model of a cyclic or multicyclic molecule is built. Embedding this method in an evolutionary algorithm results in a de novo design tool capable of altering the number and nature of cycles in species such as transition metal compounds with multidentate ligands in terms of, for example, ligand denticity, type and length of bridges, identity of bridgehead terms, and substitution pattern. An application of the method to the design of multidentate nitrogen-based ligands for Fe(II) spin-crossover (SCO) compounds is presented. The best candidates display multidentate skeletons new to the field of Fe(II) SCO yet resembling ligands deployed in other fields of chemistry, demonstrating the capability of the approach to explore structural variation and to suggest unexpected and realistic molecules, including structures with cycles not found in the building blocks.