Papers by Keyword: Block

Abstract: This research studies the properties of Porous Concrete Paving Blocks (PCPB) with different sizes of coarse aggregate. Coarse aggregate (CA) is the main component in manufacturing PCPB. Three different sizes of coarse aggregate were used; 1) CA 5 – 10 mm as a control, 2) CA 5 – 8 mm and 3) CA 8 – 10 mm. Furthermore, a series of test were conducted such as density, compressive strength, porosity and skid resistance test to determine the properties of the blocks. It was found that the size of coarse aggregate affects the strength and porosity of the blocks. The strength was reduced approximately in the range 5 % to 17 % from the control blocks. However, it is vice versa with porosity result which porosity of the blocks increased in between 5 % to 10 %. This shows that the blocks suitable for use in vehicle area where help in reduce the water ponding on pavement surface and also increased the skid resistance between the vehicle tires and pavement.

Abstract: To improve compression performance, and realize the automatic selection of compression algorithms in processing images without the prior information, the regularity relationship between compression algorithms and image features is studied, and a preprocessing scheme of block and classification based on image features has been proposed in this paper. Compression algorithms pre and post preprocessing scheme are investigated for the same 100 images. Our scheme achieves the larger peak signal to noise ratio (PSNR), which demonstrates the effectiveness of the proposed preprocessing scheme of block and classification in improving compression performance and selecting suitable algorithm to process image without the prior information.

Abstract: In the field of geotechnical engineering, a numerical simulation model is established by meshing a three-dimensional geological model, which is composed of many seamlessly connected blocks. Each block is enclosed with constrained, triangulated boundary surfaces and called as a constrained block. Due to the complexity of geological structures, a three-dimensional geological model is very complicated in most cases, and will be very difficult to decompose this kind of model into hexahedral mesh by those commonly-used methodologies. Thus, we propose a new mesh generation method which is special for blocks with constrained, triangulated boundary surfaces: hexahedron-dominant mesh generation based on templates (HMGT). In this method, several regular blocks including cuboids, prism, pyramid, tetrahedron, cylinder and their combinations, are decomposed into hexahedron-dominant meshes that serve as mesh templates. Then, a constrained block is abstracted into a simple block, and the simple block is divided into two parts by shrinking: the crust and core. Next, a mesh template of regular blocks or their combinations is selected and mapped to the core of the simple block, and the crust of which is filled with pyramids and tetrahedra in order to obtain the subdivision of the simple block. Finally, the mesh of a simple block is directly mapped to the original constrained block to generate target hexahedron-dominant mesh.

Abstract: Taking the block of a diesel engine as example, the entity’s geometric model is constructed according to reasonable simplification of design. Research was made on the effects of the FEM modal analysis results with different meshing densities.The results provide reference for the choice of element in further engine modal analysis. The results also provide basis for further structure dynamic analysis and control of noise of the diesel engine.

Abstract: The current image registration technique based on gray-level information has shortcomings on time and amount of computation brought by the whole image registration, this paper proposes a quick registration method, which makes a combination of image information entropy and cross-correlation matrix: First, segmenting the target image into blocks and calculating to get the maximum entropy image block, then using it as a template to calculate the cross-correlation matrix with floating image; Second, making the point where the maximum cross-correlation value ​​is as the upper left corner, grasping a same-size block with template on floating image; Finally, obtaining registration parameters through calculation for these two blocks to achieve the purpose of registration. Experimental results show that this method has less computational complexity with the similar registration results, and takes less time. It’s effective and feasible.

Abstract: Recycling and reuse of materials is seen as the most evident solution for sustainable development. One aspect relevant to this development refers to integration of engineering to devise ways that enable the reuse of materials considered as waste, but with great potential of applicability in the building industry itself, through the generation of appropriate technologies and products that can be an alternative to social housing. So, this research aims to propose the use of PET bottles incorporated in blocks for the implementation of masonry that provides a thermal insulation in social housing. For the execution of the blocks, the PET bottles were inserted and centered in wooden molds easily made, which were subsequently filled with mortar. Three walls were executed in masonry with conventional ceramic brick, and three walls with blocks of PET for comparison of performance in thermal, acoustic, and mechanical behavior, varying the mix proportion of mortar. The thermal test consisted of preparing panels having a height of 1.20 m and a width of 1.00 m, instrumented with five thermo pair in both sides, measuring the temperatures at the surface of incidence of the heat source and on the opposite side. The acoustic performance test was done in two ways, a pure and a more complex method, using a reverberating chamber, always placing a sound source on one side and measuring the sound pressure after the wave crossed the walls already thermally tested. To obtain the mechanical performance, measurements, the same panels were tested with compression in a structures laboratory. The masonry made with PET blocks showed in thermal tests, performance similar behavior to those obtained in conventional masonry. In the acoustic tests, masonry blocks made with PET were superior to masonry with ceramic blocks. In tests concerning the mechanical performance, all three PET block walls reached greater tensile strength than those with ceramic bricks. Therefore the blocks with PET can be used as sealing bricks. Their manufacturing process is simple and could be applied for use with poor populations with the support of an institution to produce that element of construction, generating employment and income.

Abstract: This study introduces a modified bidimensional empirical mode decomposition method to deal with high resolution images. To avoid solving large linear equations and calculating large matrix, the images are split into several blocks, processed individually, and subsequently joined into one. Thus, the complexity of time and space is lowered efficiently.

Abstract: The task is solved in connection with Ministry of Industry and Trade project which is involved in development of a complex building programme based on high quality gypsum binder from secondary raw materials. Within one of sub-stages a solution of production of small plaster elements is subject of the project which should present a basic unit for construction of interior plaster partition walls. In the framework of the task a cast of plaster shaped block was carried out using a pilot form of own production. A plaster produced in optimised pilot way from the synthetic gypsum modified with plasticizer and retarding additive was used as a filler binder. After demoulding the produced block was exposed in laboratory environment and tested for setting of selected required properties according to standard EN 12859 (dimensions, density, flatness, tensile strength on bend, pH).

Abstract: The massive rock slope is made up of rocks and structural surface. The existence and strength of the structural surface decides the stability of the rock mass. By adopting the lower bound method for the plastic limit analysis of wedge slope, we can easily calculate the stability of the rocky slope under various circumstances. To apply this method, we first took the wedge-shaped slide block as a complex of rigid block and structural surface for the analysis of the slope stress under the function of anchor bolts, the integrated function of rocks and structural surfaces being considered. Then, on the basis of the lower bound theory for the plastic limit analysis, a mathematical programming model which takes safety factor of slope stability as the object function is established. This model has to meet the equilibrium condition of the bolt, the Mohr-Coulomb yield condition and the boundary condition of slope. In the end, a classic model of wedge is analyzed and its lower bound solution is worked out. This result is compared to the result worked out by limiting equilibrium to test the validity of the measure and procedure used in this paper.

Abstract: Based on the lower bound theory for the plastic limit analysis, rock slope is divided into rigid block and structural surface. And the mathematical programming model which takes the safety factor as the objective function is established for the calculation of slope stability. This model has to meet the balance equations of the blocks, the Mohr-Coulomb yield conditions and the boundary conditions of slope. In the end, a classic model of rock slope on consideration of the pore water pressure and earthquake force is analyzed, and its lower bound solution is worked out. This result is compared to the result worked out by limiting equilibrium to test the validity and correctness of the method and procedure used in this paper.